AGRICULTURAL DEVELOPMENT IN TONGAN ......i AGRICULTURAL DEVELOPMENT IN TONGAN PREHISTORY: AN...

i

AGRICULTURAL DEVELOPMENT IN

TONGAN PREHISTORY: AN

ARCHAEOBOTANICAL

PERSPECTIVE

A Dissertation

by

ELLA USSHER

A thesis submitted for the degree of Doctor of Philosophy

at the Australian National University

June 2015

School of Culture, History and Language

Department of Archaeology and Natural History

ii

DECLARATION

The research presented here is based on original fieldwork, as well as analysis of micro-

and macrobotanical assemblages excavated by the author on Tongatapu, Kingdom of

Tonga.

I certify that, except where it is stated otherwise, this dissertation is the result of my own

original investigation.

Ella Ussher

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Acknowledgements

The completion of this thesis would not have been possible without the contribution and support

of a number of people. Firstly, I would like to thank my Chair of Panel Assoc. Prof. Geoff Clark

for proposing this project and supporting my fieldwork in Tonga, as well as guiding the final

shaping of the written component of my research. My other supervisors, especially Janelle

Stevenson and Matiu Prebble, provided me with invaluable technical support over the last four

years in both the construction of my comparative collection and the analysis of archaeological

material. Many other staff and students at the ANU provided me with specialised advice. These

included Dr Jack Fenner (statistics), Dr Frank Brinks (SEM), Dr Anne Prins (histology), Feli

Hopf and Jay Chin (microbotanical labwork), Rose Whitau (macrobotanical labwork) and

Maxine MacArthur (copy editing). To these people, I am very grateful for their time and sharing

of experience and equipment, without which this research could not have been completed.

On a more personal level, I wish to give a massive thank you to my partner Josh for being so

understanding of the time and effort that needed to go into this PhD project. His love and

support ensured that I retained my sanity at the very end and was well looked after as we

prepared to welcome our little girl into the world. Thanks and lots of love also needs to go to my

family back in NZ who encouraged me to go to Canberra and take my academic career further

so that I could follow my passion for archaeobotany. Close friends and colleagues from the

ANU such as Katherine Seikel, Stuart Hawkins, Jay Chin, Rebecca Jones, Mirani Litster, Feli

Hopf, Christian Reepmeyer, Tim Maloney, Rose Whitau, Ben Shaw, Justin Lewis, and Matthieu

Leclerc all helped create a fun and collegial atmosphere both on and off campus. Finally, I

would also like to express my gratitude to those who helped distract me from my thesis when I

really needed a break by allowing me to follow my other passion in horses, and providing

amazing friendships along the way that I will value forever (Maxine, Ann, Wendy, Keryn,

Claire, Cathy, Jeremy, Fia, and Kaaren).

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Abstract

This thesis presents the results of an archaeobotanical study of agricultural development in the

Kingdom of Tonga. Prior to this study, there has been no direct archaeological evidence for

agriculture in Tongan prehistory. Through the implementation of systematic archaeobotanical

techniques, this study aimed to fill this gap and address two key research questions: 1) whether

early colonisers were dependent on introduced crops, or if human dispersal was fuelled

predominantly by the exploitation of natural resources; and 2) whether archaeobotanical data

can provide new evidence to examine the role of agriculture within the development of the

maritime chiefdom in Tonga through agroecological modelling.

This research was divided into two main phases. The first involved the construction of a

comprehensive comparative collection for macrobotanical (vegetative storage and fruit

parenchyma and endocarp), and microbotanical (starch) components of economic and

supplementary plant taxa from Tonga. As part of this, a study of the morphological attributes of

starch and parenchyma was conducted that incorporated multivariate statistical analyses of

diagnostic attributes. Two methods for taxonomic classification were suggested: automated

classification using Discriminant Function Analysis (DFA) of starch, and the use of an

Identification Flowchart Key for parenchyma.

In the second phase of research, archaeobotanical data from three sites on Tongatapu,

representing three different time periods in Tongan prehistory, is presented. Macrobotanical and

microbotanical remains were extracted from these sites using flotation, wet-sieving and bulk

stratigraphic sampling and compared to a comprehensive reference collection using a

combination of SEM and light microscopy. Sampled cultural deposits at Talasiu (2750-2650 cal

BP), Leka (1300-1000 cal BP) and Heketa (800-600 cal BP) present new insights into the role

of plant taxa within late-Lapita, the Formative Period, and early stages of the Classic Tu’i

Tonga chiefdom. Modelling using techniques from Human Ecology, specifically agroecology,

replicated past production systems using measures of system efficiency such as nutritional value

of taxa, labour investment and productivity in terms of yields. These were compared to

expectations based on current literature, and a revised chronology for agricultural development

and links to social complexity is presented.

This study demonstrates that multivariate statistical analysis and identification

flowcharts enable the discrimination of starch and vegetative storage parenchyma from most

Tongan plant taxa based on metric and nominal morphological attributes. When applied to

archaeobotanical data these techniques indicate that most staple cultigens and some

supplementary or famine foods were brought to Tonga within a few hundred years of initial

Lapita colonisation. Late prehistoric introductions likely included the sweet potato (Ipomoea

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batatas) by 600 BP, transported via East Polynesia through the extensive trade networks of the

developing Tongan state. Modelling past production systems linked decreased system

nutritional efficiency over time to horticultural specialisation in primary crops and increasingly

centralised government on Tongatapu. Critically, this analysis modelled the high nutritional

efficiency of Lapita subsistence, and linked this to the division of labour investment between

both economic and supplementary species within a decentralised social hierarchy.

Keywords: archaeobotany, starch, parenchyma, microfossils, Tonga, archaeology, agriculture,

agroecology, production systems, Lapita

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Table of Contents

Acknowledgements iii Abstract iv Table of Contents vi List of Tables ix List of Figures xiii List of Abbreviations xvii Chapter 1 Introduction 1

Research aims and objectives 1 Theoretical framework 5 Thesis organisation 6

Chapter 2 Tongan Agriculture in the Pacific Context 9

Research to date 9 Geographic and climatic limitations to agricultural modelling 10 Ethno-historic accounts of plant cultivation in Tonga: 12 Archaeobotany of cultigens in the Pacific 20 Tonga in the Pacific: A summary 30

PART ONE- AN ARCHAEOBOTANICAL COMPARATIVE COLLECTION FOR

TONGA 32 Chapter 3 Reviewing Microbotanical Analysis 33

Biology of starch and identification potential 33 Starch taphonomy 35 Modern starch contamination 42 Sampling strategies and extraction techniques 44

Chapter 4 Reviewing Parenchyma 48

Fresh and charred parenchyma morphology 48 Taphonomic factors affecting macrobotanical preservation 49 Collection and sampling of parenchyma 52 Parenchyma identification 54

Chapter 5 Comparative Collection and Morphometric Studies of Pacific Cultigens 57

Species selection 57 Field collection 58 Laboratory processing of samples 59

Starch processing 59 Histology 60 Experimental charring 61

Recording 62 Light microscopy 62 Scanning Electron Microscopy 62

Morphology of native starch 63 Starch morphology 64 Multivariate statistical analysis of starch 76

Morphology of vegetative storage parenchyma 82 Morphological analysis of fresh samples 82 Description of charcoal 100 Development of an Identification Flowchart Key 106

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PART TWO- DEVELOPMENT OF PREHISTORIC AGRICULTURE IN TONGA 112 Chapter 6 Sites and Field Sampling Strategy 113

Methodology for field sampling of archaeological sediments 113 Site selection 113 Field methods 114

Site descriptions 116 Talasiu (TO-Mu-2) 116 Leka (J17) 117 Heketa (TO-Nt-2) 118

Stratigraphic descriptions 119 Talasiu (TO-Mu-2) 119 Leka (J17) 120 Heketa (TO-Nt-2) 122

AMS dating of cultural contexts 124

Chapter 7 Laboratory Methods 126

Microbotanical analysis: Starch residues 126 Experimentation with starch extraction techniques 126 Laboratory processing: Revised starch extraction protocol 132 Light Microscopy 134 Archaeological starch classification: Assemblage-typology approach 134 Archaeological starch classification: Multivariate statistical analysis 135

Macrobotanical analysis: Charred parenchyma and endocarp 136 Laboratory analysis 136

Chapter 8 Results 138

Macrobotanical analysis 138 Quantification of charcoal 138 Parenchyma distribution and identification: Talasiu TP2 case study 142

Microbotanical analysis 144 Extraction, quantification and distribution 144 Identification: Assemblage-typology approach 147 Identification: Multivariate statistics—Discriminant Function Analysis 150

Comparison of modern Pacific production systems 160 Nutrition 161 Labour investment 178 Outputs 187 Output to input ratios: Efficiency calculation 194 System efficiency comparison and system classification 202

Comparison of prehistoric production systems 209 Nutritional comparison of archaeological species 209 Efficiency comparison of archaeological species and production systems 215

Chapter 9 Discussion 221

Timing and nature of plant introductions into Tonga 221 Spondias dulcis— Anacardiaceae 222 Alocasia macrorrhiza— Araceae 222 Amorphophallus paeoniifolius— Araceae 223 Colocasia esculenta— Araceae 223 Cyrtosperma merkusii— Araceae 224 Cocos nucifera— Arecaceae 225 Ipomoea batatas— Convolvulaceae 225

viii

Dioscorea spp.— Dioscoreaceae 226 Inocarpus fagifer— Fabaceae 227 Barringtonia asiatica— Lechythidaceae 228 Artocarpus altilis— Moraceae 228 Musa spp.— Musaceae 229 Piper methysticum— Piperaceae 230 Curcuma longa and Zingiber spp.— Zingiberaceae 231

Modelling archaeological production systems 232 Feasibility of modelling 232 Expected modelling outcomes 234 Modelling Talasiu (TO-Mu-2) 240 Modelling Leka (J17) 244 Modelling Heketa (TO-Nt-2) 247 Comparison of expected and modelled outcomes 250 Specialisation and system efficiency 255 Contamination at Leka and Heketa 256

Linking archaeobotanical data to island colonisation and social complexity 257

Chapter 10 Conclusion 260

Meeting research aims and objectives 260 Future recommendations 267

Micro- and macrobotanical techniques 267 Archaeobotanical research in Tonga and the Pacific 269

Bibliography 271 Appendix A- Species in Reference Collection 294 Appendix B- Description of Parenchyma 296 Appendix C- Starch Images 326 Appendix D- Archaeobotanical Research in the Pacific 331

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List of Tables

TABLE 2.1 LIST OF SPECIES RECORDED IN EARLY ETHNO-HISTORIC ACCOUNTS FROM TONGA. ................... 19

TABLE 5.1 HILUM FISSURING OF REFERENCE SPECIES ................................................................................. 66

TABLE 5.2 THREE-DIMENSIONAL SHAPES OF REFERENCE SPECIES ............................................................... 68

TABLE 5.3 SUMMARY OF STARCH MORPHOLOGY WITHIN REFERENCE COLLECTION .................................... 74

TABLE 5.4 DESCRIPTION OF METRIC AND BINARY VARIABLES USED DURING DISCRIMINANT FUNCTION

ANALYSIS........................................................................................................................................... 76

TABLE 5.5 SPECIES INCLUDED IN CENTRIC AND ECCENTRIC DATASETS FOR TONGAN ANALYSIS ................. 78

TABLE 5.6 GROUND TISSUE CELL SHAPES OF TAXA IN REFERENCE COLLECTION ......................................... 84

TABLE 5.7 GROUND TISSUE CELL DIMENSIONS OF TAXA IN THE REFERENCE COLLECTION .......................... 84

TABLE 5.8 VASCULAR TISSUE ARRANGEMENTS OF TAXA IN REFERENCE COLLECTION ................................ 91

TABLE 5.9 SUMMARY OF PARENCHYMA MORPHOLOGY WITHIN REFERENCE COLLECTION .......................... 96

TABLE 5.10 DESCRIPTION OF MORPHOLOGICAL MODIFICATION WITHIN GROUND TISSUE OF CHARRED

SAMPLES IN THE COMPARATIVE COLLECTION ................................................................................... 103

TABLE 5.11 DESCRIPTION OF MORPHOLOGICAL MODIFICATION WITHIN VASCULAR TISSUE OF CHARRED

SAMPLES IN THE COMPARATIVE COLLECTION ................................................................................... 104

TABLE 8.1 SUMMARY OF TOTAL MACROBOTANICAL ASSEMBLAGES FROM ALL SITES AND TEST-PITS ....... 139

TABLE 8.2 QUANTIFICATION OF COCONUT ENDOCARP FROM ALL SITES AND TEST-PITS ............................ 140

TABLE 8.3 QUANTIFICATION OF OTHER ENDOCARP FROM ALL TEST UNITS ............................................... 141

TABLE 8.4 QUANTIFICATION OF WOOD CHARCOAL AND PARENCHYMA FROM ALL TEST UNITS ................. 142

TABLE 8.5 DISTRIBUTION AND IDENTIFICATION OF PARENCHYMA EXTRACTED FROM TALASIU TP2 ........ 144

TABLE 8.6 OVERALL QUANTITIES (COUNTS) OF STARCH EXTRACTED FROM ALL SAMPLED TEST UNITS AT

TALASIU (TO-MU-2) ........................................................................................................................ 145

TABLE 8.7 DISTRIBUTION OF STARCH COUNTS WITHIN TALASIU TP2 ....................................................... 146

TABLE 8.8 DISTRIBUTION OF STARCH COUNTS WITHIN LEKA TP2 ............................................................ 146

TABLE 8.9 DISTRIBUTION OF STARCH COUNTS WITHIN LEKA TP4 ............................................................ 147

TABLE 8.10 DISTRIBUTION OF STARCH COUNTS WITHIN HEKETA TP3 ...................................................... 147

TABLE 8.11 TABLE OUTLINING SUGGESTED FAMILY OF ORIGIN OF ARCHAEOLOGICAL STARCH TYPES FROM

TALASIU TP2. .................................................................................................................................. 149

TABLE 8.12 DISTRIBUTION OF PRELIMINARY IDENTIFICATIONS WITHIN TALASIU TP2 USING THE

ASSEMBLAGE-TYPOLOGY APPROACH ............................................................................................... 150

TABLE 8.13 LEVELS OF CONFIDENCE FROM DFA CLASSIFICATION OF ARCHAEOLOGICAL STARCH FROM

TALASIU TP2. NB HIGH CONFIDENCE (BLACK), MODERATED CONFIDENCE (MEDIUM GREY) AND LOW

CONFIDENCE (LIGHT GREY) .............................................................................................................. 153

TABLE 8.14 FINAL TABLE DOCUMENTING SPECIES REPRESENTED BY ARCHAEOLOGICAL STARCH WITHIN

TALASIU TP2 NB PRESENCE INDICATED BY BLACK SQUARES .......................................................... 155


LEKA TP2. NB HIGH CONFIDENCE (BLACK), MODERATED CONFIDENCE (MEDIUM GREY) AND LOW

CONFIDENCE (LIGHT GREY) .............................................................................................................. 155


LEKA TP2 ........................................................................................................................................ 156

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LEKA TP4. NB HIGH CONFIDENCE (BLACK), MODERATED CONFIDENCE (MEDIUM GREY) AND LOW

CONFIDENCE (LIGHT GREY) ............................................................................................................... 156


LEKA TP4 ......................................................................................................................................... 157


HEKETA TP3. NB HIGH CONFIDENCE (BLACK), MODERATED CONFIDENCE (MEDIUM GREY) AND LOW

CONFIDENCE (LIGHT GREY) ............................................................................................................... 158


HEKETA TP3 ..................................................................................................................................... 158

TABLE 8.21 NUTRITIONAL FIGURES AND RANKINGS FOR SPECIES WITHIN THE GADIO ENGA SYSTEM

ACCORDING TO CALORIES, PROTEIN, FATS, CARBOHYDRATES AND TOTAL NUTRITION FIGURES (DATA

FROM DORNSTREICH 1974, 1978) ..................................................................................................... 163

TABLE 8.22 NUTRITIONAL FIGURES AND RANKINGS FOR SPECIES WITHIN BELLONA ISLAND SYSTEM

ACCORDING TO CALORIES, PROTEIN, FATS, CARBOHYDRATES AND TOTAL NUTRITION FIGURES (DATA

FROM CHRISTIANSEN 1975) .............................................................................................................. 166

TABLE 8.23 NUTRITIONAL FIGURES AND RANKINGS FOR SPECIES WITHIN ANUTAN SYSTEM ACCORDING TO

CALORIES, PROTEIN, FATS, CARBOHYDRATES AND TOTAL NUTRITION FIGURES (DATA FROM YEN

1973B) .............................................................................................................................................. 170

TABLE 8.24 NUTRITIONAL FIGURES AND RANKINGS FOR SPECIES WITHIN TONGAN SYSTEM ACCORDING TO

CALORIES, PROTEIN, FATS, CARBOHYDRATES AND TOTAL NUTRITION FIGURES (DATA FROM MINISTRY

OF AGRICULTURE AND FORESTRY 2001) .......................................................................................... 173

TABLE 8.25 NUTRITIONAL FIGURES AND RANKINGS FOR SPECIES WITHIN ONTONG JAVA SYSTEM

ACCORDING TO CALORIES, PROTEIN, FATS, CARBOHYDRATES AND TOTAL NUTRITION FIGURES SYSTEM

(DATA FROM BAYLISS-SMITH 1973, 1986) ....................................................................................... 176

TABLE 8.26 STATISTICAL COMPARISON OF SPECIES’ GROUPINGS IN EXAMPLE SYSTEMS ACCORDING TO

OVERALL NUTRITION FIGURES/100G ................................................................................................. 178

TABLE 8.27 LABOUR INVESTMENT INTO SPECIES WITHIN THE GADIO ENGA SYSTEM (DATA FROM

DORNSTREICH 1974, 1978) ............................................................................................................... 179

TABLE 8.28 LABOUR INVESTMENT INTO SPECIES WITHIN THE BELLONA IS SYSTEM (DATA FROM

CHRISTIANSEN 1975) ........................................................................................................................ 181

TABLE 8.29 LABOUR INVESTMENT INTO SPECIES WITHIN THE ANUTAN SYSTEM (DATA FROM YEN 1973B)

......................................................................................................................................................... 182

TABLE 8.30 LABOUR INVESTMENT INTO SPECIES WITHIN THE TONGAN SYSTEM (DATA FROM MINISTRY OF

AGRICULTURE AND FORESTRY 2001) ............................................................................................... 184

TABLE 8.31 LABOUR INVESTMENT INTO SPECIES WITHIN THE ONTONG JAVA PLANT PRODUCTION SYSTEM


TABLE 8.32 STATISTICAL COMPARISON OF SPECIES’ GROUPINGS IN EXAMPLE SYSTEMS ACCORDING TO

LABOUR INPUT FIGURES .................................................................................................................... 187

TABLE 8.33 OUTPUT COMPARISON OF SPECIES IN GADIO ENGA PLANT PRODUCTION SYSTEM (DATA FROM

DORNSTREICH 1974, 1978) ............................................................................................................... 188

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TABLE 8.34 OUTPUT COMPARISON OF SPECIES IN BELLONA ISLAND SYSTEM (DATA FROM CHRISTIANSEN

1975) ................................................................................................................................................ 189

TABLE 8.35 OUTPUT COMPARISON OF SPECIES IN ANUTAN SYSTEM (DATA FROM YEN 1973B)................. 191

TABLE 8.36 OUTPUT COMPARISON OF SPECIES IN TONGAN SYSTEM (DATA FROM MINISTRY OF


TABLE 8.37 OUTPUT COMPARISON OF SPECIES IN ONTONG JAVA PRODUCTION SYSTEM (DATA FROM

BAYLISS-SMITH 1973, 1986) ............................................................................................................ 194

TABLE 8.38 YIELD RATIOS FOR ARCHAEOLOGICAL SPECIES IN ALL MODERN PRODUCTION SYSTEMS

(KG/TIME UNIT OF LABOUR) .............................................................................................................. 196

TABLE 8.39 OUTPUT TO INPUT RATIOS FOR ARCHAEOLOGICAL SPECIES USING GADIO ENGA DATA .......... 198

TABLE 8.40 OUTPUT TO INPUT RATIOS FOR ARCHAEOLOGICAL SPECIES USING BELLONA DATA ............... 199

TABLE 8.41 OUTPUT TO INPUT RATIOS FOR ARCHAEOLOGICAL SPECIES USING ANUTAN DATA ................. 200

TABLE 8.42 OUTPUT TO INPUT RATIOS FOR ARCHAEOLOGICAL SPECIES USING TONGAN 2001 DATA ........ 201

TABLE 8.43 OUTPUT TO INPUT RATIOS FOR ARCHAEOLOGICAL SPECIES USING ONTONG JAVAN DATA ..... 202

TABLE 8.44 STATISTICAL COMPARISON OF NUTRITIONAL VALUE OF ARCHAEOLOGICAL AND EXPECTED

ETHNOGRAPHIC SPECIES ................................................................................................................... 215

TABLE 8.45 STATISTICAL COMPARISON OF NUTRITIONAL VALUE OF SPECIES GROUPS WITHIN

ARCHAEOLOGICAL SYSTEMS AT TALASIU, LEKA AND HEKETA ........................................................ 215

TABLE 9.1 LIST OF ALL SPECIES IDENTIFIED ARCHAEOBOTANICALLY WITHIN THIS STUDY ....................... 222

TABLE 9.2 IDENTIFIED FAMILIES AND SPECIES WITHIN ARCHAEOBOTANICAL REMAINS FROM TALASIU (TO-

MU-2) .............................................................................................................................................. 241

TABLE 9.3 YIELD RATIOS FOR SPECIES IDENTIFIED AT TALASIU MODELLED USING COMPARATIVE SYSTEMS

......................................................................................................................................................... 243

TABLE 9.4 LABOUR INPUTS FOR SPECIES IDENTIFIED AT TALASIU MODELLED USING COMPARATIVE SYSTEMS

......................................................................................................................................................... 243

TABLE 9.5 STATISTICAL COMPARISON OF LABOUR INPUTS FOR GROUPINGS AT TALASIU IN TERMS OF MEAN

DIFFERENCE MODELLED USING COMPARATIVE SYSTEMS .................................................................. 243

TABLE 9.6 IDENTIFIED FAMILIES AND SPECIES WITHIN ARCHAEOBOTANICAL REMAINS FROM LEKA (J17) 245

TABLE 9.7 YIELD RATIOS FOR SPECIES IDENTIFIED AT LEKA MODELLED USING COMPARATIVE SYSTEMS . 246

TABLE 9.8 LABOUR INPUTS FOR SPECIES IDENTIFIED AT LEKA MODELLED USING COMPARATIVE SYSTEMS

......................................................................................................................................................... 247

TABLE 9.9 STATISTICAL COMPARISON OF LABOUR INPUTS FOR GROUPINGS AT LEKA IN TERMS OF MEAN


TABLE 9.10 IDENTIFIED FAMILIES AND SPECIES WITHIN ARCHAEOBOTANICAL REMAINS FROM HEKETA (TO-

NT-2) ............................................................................................................................................... 248

TABLE 9.11 YIELD RATIOS FOR SPECIES IDENTIFIED AT HEKETA MODELLED USING COMPARATIVE EXAMPLE

SYSTEMS........................................................................................................................................... 249

TABLE 9.12 LABOUR INPUTS FOR SPECIES IDENTIFIED AT HEKETA MODELLED USING COMPARATIVE

EXAMPLE SYSTEMS ........................................................................................................................... 249

TABLE 9.13 STATISTICAL COMPARISON OF LABOUR INPUTS FOR GROUPINGS AT HEKETA IN TERMS OF MEAN


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TABLE 9.14 COMPARISON OF MODELLED SYSTEM EFFICIENCY WITH RATIOS OF PRIMARY TO

SUPPLEMENTARY SPECIES ................................................................................................................. 255

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List of Figures

FIGURE 5.1 FLOWCHART SHOWING METHODOLOGY FOR THE IMAGING AND RECORDING OF STARCH AND

PARENCHYMA WITHIN THE REFERENCE COLLECTION.......................................................................... 59

FIGURE 5.2 DIAGRAM SHOWING BASIC FEATURES OF STARCH GRANULE MORPHOLOGY ............................. 65

FIGURE 5.3 BOX PLOT OF STARCH GRANULE LENGTHS WITHIN REFERENCE COLLECTION ............................ 72

FIGURE 5.4 BOX PLOT OF STARCH GRANULE WIDTHS WITHIN REFERENCE COLLECTION .............................. 72

FIGURE 5.5 BOX PLOT OF STARCH GRANULE HILUM POSITION TO LENGTH RATIOS WITHIN REFERENCE

COLLECTION ....................................................................................................................................... 73

FIGURE 5.6 PLOT SHOWING DISCRIMINATION OF SPECIES WITHIN CENTRIC DATASET ACCORDING TO FIRST

TWO CANONICAL VARIATES ................................................................................................................ 79

FIGURE 5.7 PLOT SHOWING DISCRIMINATION OF 15 SPECIES WITHIN ECCENTRIC DATASET ACCORDING TO

FIRST TWO CANONICAL VARIATES ...................................................................................................... 79

FIGURE 5.8 CLASSIFICATION MATRIX FOR THE OVERALL CENTRIC DATASET, SHOWING HIGHEST

DISCRIMINATION OF COLOCASIA ESCULENTA, INOCARPUS FAGIFER, MORINDA CITRIFOLIA AND SPONDIAS

DULCIS (SPECIES LISTED VERTICALLY IN THE FIRST COLUMN ARE THE ORIGINAL SPECIES, AND THOSE

LISTED HORIZONTALLY IN THE TOP ROW ARE THE SPECIES TO WHICH DFA CLASSIFIED GRANULES) .. 81

FIGURE 5.9 CLASSIFICATION MATRIX FOR THE OVERALL ECCENTRIC DATASET, SHOWING HIGHEST

DISCRIMINATION OF COLOCASIA ESCULENTA, CURCUMA LONGA, AND DIOSCOREA PENTAPHYLLA

(SPECIES LISTED VERTICALLY IN THE FIRST COLUMN ARE THE ORIGINAL SPECIES, AND THOSE LISTED

HORIZONTALLY IN THE TOP ROW ARE THE SPECIES TO WHICH DFA CLASSIFIED GRANULES) .............. 81

FIGURE 5.10 BOX PLOT OF PARENCHYMA CELL LENGTHS OF TAXA IN THE REFERENCE COLLECTION .......... 87

FIGURE 5.11 BOX PLOT OF PARENCHYMA CELL WIDTHS OF TAXA IN THE REFERENCE COLLECTION ............ 88

FIGURE 5.12 PLOT SHOWING CLASSIFICATION OF PARENCHYMA WITHIN REFERENCE COLLECTION USING

DFA ................................................................................................................................................... 89

FIGURE 5.13 DESCRIPTION OF VASCULAR BUNDLE ARRANGEMENTS WITHIN VEGETATIVE PARENCHYMA

(FROM HATHER 2000) ........................................................................................................................ 90

FIGURE 5.14 BOX PLOT SHOWING VASCULAR BUNDLE LENGTHS WITHIN REFERENCE COLLECTION

ACCORDING TO TISSUE ARRANGEMENT .............................................................................................. 94

FIGURE 5.15 FLOWCHART 1 USED AS AN IDENTIFICATION KEY TO IDENTIFY UNKNOWN PARENCHYMATOUS

SAMPLES WHEN VASCULAR TISSUES ARE VISIBLE ............................................................................. 110

FIGURE 5.16 FLOWCHART 2 USED AS AN IDENTIFICATION KEY TO IDENTIFY UNKNOWN PARENCHYMATOUS

SAMPLES WHEN NO VASCULAR TISSUES ARE VISIBLE........................................................................ 111

FIGURE 6.1 MAP SHOWING LOCATION OF ARCHAEOLOGICAL SITES INCLUDED IN THIS STUDY FROM

TONGATAPU ..................................................................................................................................... 116

FIGURE 6.2 STRATIGRAPHIC DIAGRAM OF CULTURAL DEPOSITS WITHIN TALASIU TP2 ............................. 120

FIGURE 6.3 STRATIGRAPHIC DIAGRAM OF CULTURAL DEPOSITS WITHIN LEKA TP2 .................................. 122

FIGURE 6.4 STRATIGRAPHIC DIAGRAM OF CULTURAL DEPOSITS AT LEKA TP4 ......................................... 122

FIGURE 6.5 STRATIGRAPHIC DIAGRAM OF CULTURAL DEPOSITS WITHIN HEKETA TP3.............................. 124

FIGURE 6.6 CALIBRATION OF RADIOCARBON DATES FROM TALASIU (TO-MU-2), LEKA (J17) AND HEKETA

(TO-NT-2) ....................................................................................................................................... 125

FIGURE 8.1 COMPOSITION OF OVERALL MACROBOTANICAL ASSEMBLAGE IN TERMS OF ABUNDANCE....... 139

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FIGURE 8.2 BOX PLOT DEMONSTRATING MAXIMUM LENGTH COMPARISON OF ARCHAEOLOGICAL STARCH

TYPE 1 WITH DIOSCOREA SPP. .......................................................................................................... 149

FIGURE 8.3 DISCRIMINANT ANALYSIS PLOT FOR CENTRIC DATASET SHOWING ELLIPSES (COLOURED DOTS

REPRESENT REFERENCE SPECIES, BLACK DOTS REPRESENT ARCHAEOLOGICAL GRAINS) ................... 152

FIGURE 8.4 DISCRIMINANT ANALYSIS PLOT FOR ECCENTRIC DATASET SHOWING ELLIPSES (COLOURED DOTS

REPRESENT REFERENCE SPECIES, BLACK DOTS REPRESENT ARCHAEOLOGICAL GRAINS) ................... 153

FIGURE 8.5 ARCHAEOLOGICAL AND REFERENCE STARCH: (A) ARCHAEOLOGICAL STARCH IDENTIFIED AS

ARTOCARPUS ALTILIS, (B) MODERN STARCH OF A.ALTILIS, (C) ARCHAEOLOGICAL STARCH IDENTIFIED

AS ALOCASIA MACRORRHIZA, (D) MODERN STARCH OF A.MACRORRHIZA, (E) ARCHAEOLOGICAL STARCH

IDENTIFIED AS AMORPHOPHALLUS PAEONIIFOLIUS, (F) MODERN STARCH OF A.PAEONIIFOLIUS, (G)

ARCHAEOLOGICAL STARCH IDENTIFIED AS BARRINGTONIA ASIATICA, (H) MODERN STARCH OF

B.ASIATICA, (I) ARCHAEOLOGICAL STARCH IDENTIFIED AS COLOCASIA ESCULENTA, (J) MODERN STARCH

OF C. ESCULENTA, (K) ARCHAEOLOGICAL STARCH IDENTIFIED AS CURCUMA LONGA, (L) MODERN

STARCH OF C.LONGA, (M) ARCHAEOLOGICAL STARCH IDENTIFIED AS CYRTOSPERMA MERKUSII, (N)

MODERN STARCH OF C.MERKUSII, (O) ARCHAEOLOGICAL STARCH IDENTIFIED AS DIOSCOREA ALATA,

(P) MODERN STARCH OF D.ALATA. ..................................................................................................... 159

FIGURE 8.6 ARCHAEOLOGICAL AND REFERENCE STARCH CONT.: (Q) ARCHAEOLOGICAL STARCH IDENTIFIED

AS DIOSCOREA BULBIFERA (R) MODERN STARCH OF D. BULBIFERA, (S) ARCHAEOLOGICAL STARCH

IDENTIFIED AS DIOSCOREA ESCULENTA, (T) MODERN STARCH OF D.ESCULENTA, (U) ARCHAEOLOGICAL

STARCH IDENTIFIED AS DIOSCOREA NUMMULARIA, (V) MODERN STARCH OF D.NUMMULARIA, (W)

ARCHAEOLOGICAL STARCH IDENTIFIED AS INOCARPUS FAGIFER, (X) MODERN STARCH OF I. FAGIFER,

(Y) ARCHAEOLOGICAL STARCH IDENTIFIED AS IPOMOEA BATATAS, (Z) MODERN STARCH OF I.BATATAS,

(AA) ARCHAEOLOGICAL STARCH IDENTIFIED AS MUSA SP., (AB) MODERN STARCH OF MUSA SP., (AC)

ARCHAEOLOGICAL STARCH IDENTIFIED AS PIPER METHYSTICUM, (AD) MODERN STARCH OF

P.METHYSTICUM, (AE) ARCHAEOLOGICAL STARCH (CONTAMINANT) IDENTIFIED AS SOLANUM

TUBEROSUM, (AF) MODERN STARCH OF S.TUBEROSUM, (AG) ARCHAEOLOGICAL STARCH IDENTIFIED

AS SPONDIAS DULCIS, (L) MODERN STARCH OF S. DULCIS. ................................................................. 160

FIGURE 8.7 NUTRITIONAL COMPARISON OF SPECIES WITHIN THE GADIO ENGA PLANT PRODUCTION SYSTEM

(DATA FROM DORNSTREICH 1974, 1978) .......................................................................................... 164

FIGURE 8.8 NUTRITIONAL COMPARISON OF SPECIES WITHIN THE BELLONA ISLAND PLANT PRODUCTION

SYSTEM, SHOWING EXPONENTIAL TREND LINES FOR HORTICULTURAL AND SEMI-CULTIVATED TAXA

(DATA FROM CHRISTIANSEN 1975) ................................................................................................... 167

FIGURE 8.9 NUTRITIONAL COMPARISON OF SPECIES WITHIN THE ANUTAN PLANT PRODUCTION SYSTEM,

SHOWING EXPONENTIAL TREND LINES FOR PRIMARY AND SUPPLEMENTARY TAXA (DATA FROM YEN

1973B) .............................................................................................................................................. 171

FIGURE 8.10 NUTRITIONAL COMPARISON OF SPECIES WITHIN THE TONGAN PLANT PRODUCTION SYSTEM,

SHOWING EXPONENTIAL TREND LINES FOR HORTICULTURAL AND SEMI-CULTIVATED TAXA (DATA

FROM MINISTRY OF AGRICULTURE AND FORESTRY 2001) ................................................................ 174

FIGURE 8.11 NUTRITIONAL COMPARISON OF SPECIES WITHIN THE ONTONG JAVA PLANT PRODUCTION

SYSTEM, SHOWING EXPONENTIAL TREND LINES FOR PRIMARY AND SUPPLEMENTARY TAXA (DATA

FROM BAYLISS-SMITH 1973, 1986) .................................................................................................. 177

xv

FIGURE 8.12 LABOUR COMPARISON OF SPECIES WITHIN THE GADIO ENGA SYSTEM (DATA FROM

DORNSTREICH 1974, 1977) .............................................................................................................. 180

FIGURE 8.13 LABOUR COMPARISON OF SPECIES WITHIN THE BELLONA ISLAND SYSTEM (DATA FROM

CHRISTIANSEN 1975) ....................................................................................................................... 181

FIGURE 8.14 LABOUR COMPARISON OF SPECIES WITHIN THE ANUTAN SYSTEM (DATA FROM YEN 1973B) 183

FIGURE 8.15 LABOUR COMPARISON OF SPECIES WITHIN THE TONGAN SYSTEM (DATA FROM MINISTRY OF


FIGURE 8.16 LABOUR COMPARISON OF SPECIES WITHIN THE ONTONG JAVA PLANT PRODUCTION SYSTEM


FIGURE 8.17 OUTPUT COMPARISON ACCORDING TO YIELD FOR SPECIES WITHIN GADIO ENGA SYSTEM (DATA

FROM DORNSTREICH 1974, 1978) .................................................................................................... 188

FIGURE 8.18 OUTPUT COMPARISON ACCORDING TO YIELD FOR SPECIES WITHIN BELLONA SYSTEM (DATA

FROM CHRISTIANSEN 1975).............................................................................................................. 190

FIGURE 8.19 OUTPUT COMPARISON ACCORDING TO YIELD FOR SPECIES WITHIN THE ANUTAN SYSTEM (DATA

FROM YEN 1973B) ............................................................................................................................ 191

FIGURE 8.20 OUTPUT COMPARISON ACCORDING TO YIELD FOR SPECIES WITHIN THE TONGAN SYSTEM (DATA

FROM MINISTRY OF AGRICULTURE AND FORESTRY 2001) ............................................................... 193

FIGURE 8.21 COMPARISON ACCORDING TO YIELD FOR SPECIES WITHIN THE ONTONG JAVA PRODUCTION

SYSTEM (DATA FROM BAYLISS-SMITH 1973, 1986) .......................................................................... 194

FIGURE 8.22 OUTPUT TO INPUT RATIO COMPARISON FOR ARCHAEOLOGICAL SPECIES WITHIN EACH SYSTEM

IN TERMS OF CALORIES ..................................................................................................................... 206


IN TERMS OF PROTEIN ....................................................................................................................... 207


IN TERMS OF FATS (NOTE VERTICAL SCALE IS LOGARITHMIC) ........................................................... 207


IN TERMS OF CARBOHYDRATES ......................................................................................................... 208

FIGURE 8.26 COMPARISON OF AVERAGE NUTRITIONAL EFFICIENCY RATIOS FOR ALL SYSTEMS (NOTE

VERTICAL SCALE IS LOGARITHMIC) .................................................................................................. 208

FIGURE 8.27 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT TALASIU (TO-MU-2) ...................... 210

FIGURE 8.28 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT TALASIU WITH EXPECTED

ETHNOGRAPHIC SPECIES. .................................................................................................................. 211

FIGURE 8.29 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT LEKA (J17) ..................................... 212

FIGURE 8.30 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT LEKA WITH EXPECTED ETHNOGRAPHIC

SPECIES ............................................................................................................................................ 213

FIGURE 8.31 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT HEKETA (TO-NT-2) ........................ 214

FIGURE 8.32 NUTRITIONAL COMPARISON OF SPECIES IDENTIFIED AT HEKETA WITH EXPECTED

ETHNOGRAPHIC SPECIES ................................................................................................................... 215

FIGURE 8.33 COMPARISON OF CALORIFIC EFFICIENCY OF ARCHAEOLOGICAL SPECIES FROM TALASIU...... 218

FIGURE 8.34 COMPARISON OF CALORIFIC EFFICIENCY OF ARCHAEOLOGICAL SPECIES FROM LEKA ........... 218

FIGURE 8.35 COMPARISON OF CALORIFIC EFFICIENCY OF ARCHAEOLOGICAL SPECIES FROM HEKETA ...... 219

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FIGURE 8.36 MODELLED ARCHAEOLOGICAL SYSTEMS ACCORDING TO CALORIFIC EFFICIENCY VALUES FROM

MODERN SYSTEMS ............................................................................................................................ 220

FIGURE 9.1 TREND TOWARDS DECREASED SYSTEM NUTRITIONAL EFFICIENCY AND INCREASED SOCIAL

COMPLEXITY AFTER LAPITA OCCUPATION AT TALASIU (2750-2650 CAL BP) ................................... 259

xvii

List of Abbreviations

BP years before present

bsl below surface level

bd below datum

ºC degrees centigrade

cal calibrated

cm centimetres

cm³ centimetres cubed

DFA Discriminant Function Analysis

hr hours

ioa instance of activity

km kilometres

m metres

m² metres square

µm micrometre

sg specific gravity

1

Chapter 1 Introduction

Plants have played a critical role throughout history, enabling human migration, colonisation

and the formation of complex societies. Many plant species have been biologically adapted to

human exploitation through genetic manipulations that increase productivity and ease

cultivation and transportation. The production and use of plants through horticultural practices

was a critical stepping stone in the development of complex societies in human history. Plants

enabled nutritionally diverse diets, but also provided useful materials such as cordage, fibre,

thatch, cooking and storage vessels, and medicines to name a few. Plant production systems

within the Pacific region are the result of transportation of plants and of concepts relating to

them, as well as localised adaptation to specific island environments. Understanding the role

that these systems played in stimulating and enabling episodes of human movement into and

within Polynesia is critical for developing models of global migration patterns.

There are two prevailing views on human-environment interactions. The first of these

argues that humans reacted passively to environmental change. This traditional perspective has

been challenged by the view that humans act as agents of change, both reacting to and

transforming the landscapes which they inhabit. Island environments represent microcosms of

this ecosystem manipulation and adaptation, and the islands of the Pacific provide an important

setting to test these views. Natural and cultural factors that affected the timing and speed of

movement, settlement patterns, technological development and the transformation of island

environments within the Pacific can arguably provide insights at a global scale.

This archaeobotanical thesis will focus on the links between plant utilisation and

migration episodes within Western Polynesia as well as on the role of plants within the

evolution of social hierarchy through agricultural development, which form core issues in

debates about Pacific settlement processes. Specifically, this thesis will investigate the

introduction and role of prehistoric crops in Tongan prehistory through a study of ancient plant

remains found in Lapita and post-Lapita archaeological sites around Tongatapu.

Research aims and objectives

A primary question examined in this thesis is whether early colonisers were dependent on

introduced crops, or if human dispersal was fuelled predominantly by the exploitation of natural

resources. On a global scale, human migration has traditionally been viewed as stimulated by

the extraction of floral and faunal food resources within diverse environmental contexts. This

stems from the causality concepts of ‘push’ and ‘pull’ factors at both place of origin and

destination, which have been utilised by demographers, geographers and archaeologists alike for

many decades (Anthony 1990; Lee 1966). The colonisation of diverse island landscapes within

the Pacific Ocean, the largest of the Earth’s oceanic divisions at 165.25 million km², has been

2

recognised as an ideal setting to test this theory. The view that exploitation rather than

adaptation drove episodes of Lapita migration into Remote Oceania was taken by Groube

(1971). His ‘strandlooper’ concept for Lapita subsistence, later adopted by Best (1984),

favoured marine exploitation over the utilisation of transported terrestrial crops and animals.

This contrasts with the ‘transported landscape’ proposed by Kirch (1984) and others (Green

1991), in which a full suite of horticultural crops and techniques was brought by Lapita

populations moving eastwards into Polynesia. These were then cultivated and intensified

through adaptation of traditional practices within the varying high volcanic, limestone and atoll

island settings of this region. The scale of ecosystem manipulation and the economic systems

that fuelled this and later pulses of migration from the Western Polynesian homeland into

Central and East Polynesia after 1500 BP are still contested. Global models such as the Ideal

Free Distribution (IFD) from Human Behavioural Ecology (HBE) have been applied to account

for modes of subsistence, new habitat suitability, and population density in predicting migratory

behaviour (Kennett et al. 2006). Comparisons have also been drawn between the migration of

food-producing people in areas such as the Pacific, Atlantic, Caribbean and the Mediterranean,

suggesting that the insularity of island and coastal landscapes affects the rate and dynamics of

colonising episodes (Dawson 2008; Keegan and Diamond 1987; Leppard 2014).

Disentangling local parameters and rates of change, as well as establishing how early

subsistence evolved as locally-adapted cultures emerged is a crucial issue within Pacific

archaeology that can be applied globally. Other archaeobotanical (Crowther 2005, 2009;

Horrocks and Bedford 2004, 2010; Horrocks and Nunn 2007; Horrocks et al. 2009) and isotopic

studies (Bentley et al. 2007; Field et al. 2009; Shaw et al. 2009; Valentin et al. 2010) have

attempted to provide new proxy evidence on Lapita and post-Lapita subsistence, with research

in Near and Remote Oceania. However, there has been very little direct evidence to corroborate

the picture these data sketch. The analysis of both micro- and macrobotanical remains from

archaeological sites has the potential to provide important new data to resolve the significance

of human-plant production systems in the colonisation of the Pacific islands 3000 years ago.

Second, this study will examine whether archaeobotanical data can provide new

evidence to examine the role of agriculture within the development of the maritime chiefdom in

Tonga. Investigation of social complexity in Tonga has often assumed a causal link between the

intensification of agriculture and the development of a complex chiefdom (Aswani and Graves

1998) or primary state (Clark et al. 2014) based on Tongatapu by 750 BP (Burley 1998). This

approach stems from the foundational work of Childe (1925), Clarke (1952), Binford (1968)

and Flannery (1965, 1968), among others, in Europe and the Americas. Simple environmental

determinism and cultural systems theory have gradually evolved into ecological and

evolutionary approaches that seek to explain the emergence of complex societies and the origins

of agriculture through the dynamic that exists between people and their environment. These

3

approaches have generally moved away from unilinear trajectories for social complexity, and

accept that multiple routes may be taken as a response to the same initial conditions. The

‘advantages’ of the adoption of agriculture did not necessarily ensure that this development

would occur, and adaptive changes that might be viewed as regressive in the direction of less

complex cultural forms also occurred (Binford 1968:331).

The islands of Polynesia present unique opportunities to study the links between

tropical production systems, and agricultural intensification in non-industrialised societies.

Testing of the ‘hydraulic hypothesis’ advanced by Wittfogel (1957), that draws a causal

connection between the managerial requirements of complex irrigation and the development of

complex socio-political structures, has been a dominant theme in Pacific research. Case studies

from locations such as the Australs (Bollt 2012), Hawaii (Earle 1980, 1991, 2012; Ladefoged

and Graves 2008; Lincoln and Ladefoged 2014; McCoy and Graves 2012; Sahlins 1958), the

Marquesas (Addison 2006; Allen 2010; Earle 1993), and Futuna (Kirch 1982, 1994) have

investigated the ties between investment in irrigation for wet taro production as landesque

capital, and the development of political economies. The outcomes of these investigations

challenged the idea of a direct link and demonstrated that territorial expansion was often the

result of increasingly intensified dryland agricultural regimes when shorter-fallow and labor-

intensive methods put pressure on the political elite to source other tracts of arable land. These

more complex chains of causality question the uncritical imposition of generic hierarchical

models of political economy that have often been derived from the largely discredited

assumptions of Boserup (1965), Wittfogel, and the unilinear “Mesopotamian Model” of political

economy, settlement pattern, and cultural evolution. ‘Expansion’, rather than ‘intensification’ of

production to create food surplus therefore represents an alternative pathway to socio-political

development both in the Pacific and elsewhere.

Research into dryland agricultural development on Tongatapu therefore presents an

important case study that can be extrapolated and applied within global models linking

production systems to social complexity. The dynamic relationship between known variables

such as the environmental limitations for irrigation, the adoption of intensive dryland

techniques, territorial expansion and centralised control of production through tributary systems

in Tongan prehistory (Awani and Graves 1998; Burley and Connaughton 2007; Green 1973;

Kirch 1988, 1994; Maude 1965; Spenneman 1986) are further explored in this thesis through a

detailed chronology of plant introduction and cultivation. Specific questions are examined, such

as whether the introduction of crops indicate trade and inter-island contact linked to socio-

political development, and also if the creation of food surplus was likely enabled through

intensification or expansion of production and the horticultural range. Did this process of

agricultural development ultimately lead to changes in social hierarchy or were these variables

inextricably linked? What factors were involved in these decision-making processes (i.e.

4

nutritional value, yield, labour investment)? This study sought to answer these research

questions as well as to challenge existing assumptions which are primarily based on a lack of

direct evidence for horticultural practices in prehistory, through systematic archaeobotanical

analysis.

The two main objectives of this research were to construct a comprehensive reference

collection for both starch and parenchyma from economic and supplementary plant species in

Tonga, and to conduct a broad archaeobotanical survey of sediments from sites on the island of

Tongatapu, from both Lapita-associated and post-Lapita contexts. Archaeobotanical techniques

utilised here focus on the identification of both micro- and macrobotanical remains of plant

storage organs. Plant microfossils such as starches, phytoliths and pollen have the potential to

inform upon human interaction with their surrounding landscapes. In particular, these small

remnants of plants can provide direct evidence for the role of plants within the diet and

subsistence of a population. Starch is produced in the roots, tubers, fruits and seeds of plants,

which are the main organs that are processed and eaten by humans (Torrence and Barton 2006).

Additionally, macro-botanical remains such as charred, desiccated or water-logged vegetative

storage parenchymatous tissue are also often diagnostic to species level (Hather 1991, 1994,

2000). These remains can enter into the archaeological record through either natural processes

or through human intervention, such as intentionally growing or processing crops on site. An

analysis of diagnostic morphological attributes of these remains was a crucial initial step

towards enabling the taxonomic identification of material extracted from archaeological

deposits, and built on the foundational work of others in the Pacific region (Babot 2003;

Crowther 2001, 2005, 2009, 2012; Hather 2000; Horrocks and Barber 2005; Horrocks et al.

2004a, 2008, 2012, 2014; Loy 1994; Oliveira 2008, 2012; Paz 2005; Torrence et al. 2004;

Wilson et al. 2010).

Three sites were targeted for this study: Talasiu (TO-Mu-2) dated to around 2750-2650

cal BP, Leka (J17 dated to 1300-1000 cal BP, and Heketa (TO-Nt-2) dated to 800-600 cal BP.

According to Burley (1998), Tongan prehistory can be divided into four key periods: Lapita

(2850-2650 BP), Plainware (2650-1550 BP), Formative Development (1550-750 BP) and

Classic Tongan Chiefdom (750-150 BP). Archaeobotanical data from these three sites on

Tongatapu has provided the basis for a revised chronology based on agricultural development

rather than material culture, and changes the way that the relationship between subsistence and

socio-political change is currently viewed in Tonga. It will be argued here that the early

colonists of Tonga were primarily foragers, with minor elements of agriculture assisting

subsistence. Agriculture was therefore not a later development in Tongan prehistory. Instead,

reliance on the core cultigens likely grew as population size increased and new crops were

introduced through trade and inter-island contact, ultimately allowing a state-level social

hierarchy to emerge through the establishment and control of surplus resources.

5

Theoretical framework

Basics of agroecology

In order to address the two primary research questions within this study, a Human Ecological

approach was taken to model and interpret the archaeobotanical data from Talasiu (TO-Mu-2),

Leka (J17), and Heketa (TO-Nt-2). More specifically, these archaeological systems were

analysed using techniques deriving from Agricultural Ecology or Agroecology, which aims to

visualise cultivation as the creation of an ecosystem or agro-ecosystem (Tivy 1990). The

management of crops and the environment through cultivation produces a habitat which allows

the crop to realise its productive potential. Within this view, the agent becomes an essential

ecological variable in the system, and the ‘ecosystem’ refers to social, cultural and economic

contexts as well as the properties of the natural environment. It is argued that due to positive and

negative feedback loops, whenever humans intercede they generate basic changes in the

functioning of the system (Cox and Atkins 1979:57). Bayliss-Smith (1977) defines four types of

productive efficiency that are calculated within this approach: indigenous efficiency (perceived

output divided by primary input or cost in human effort to supply a population with goods to

maintain and enrich it), exogenous efficiency (exported de-facto output divided by secondary

input or cost to society as a whole of maintaining and enriching any enclave within it),

technoenvironmental efficiency (Harris’ T) (total de-facto output divided by primary input), and

total efficiency (total de-facto output divided by primary and secondary inputs).

Variables considered in these agro-ecosystems often relate to the mode of subsistence,

labour inputs, yield, productivity, demography, as well as social and political constraints like

surplus requirements. Previous applications of this approach in the Pacific have attempted to

model production systems using ethnographic and historic data, and also island carrying

capacity to refine population estimates (Bartruff et al. 2012; Bayliss-Smith 1977, 1978) and

understand socio-political development (Lincoln and Ladefoged 2014). These studies vary in

detail depending on the nature of data available, but often caution against strictly linking

resource production to environmental restrictions or population pressure, as social factors also

play a significant role in determining both population and modes of subsistence (Bayliss-Smith

1978). The degree of precision required to identify the ecological, economic and social

constraints of agro-ecosystems ensures that archaeologists can only broadly hypothesise upon

the interactions between natural and cultural variables. It is difficult to extrapolate whole

prehistoric production systems from historic and ethnographic data, and how these changed over

time.

Modern comparative systems and modelling archaeological systems

Studies of modern agricultural production on Tongatapu have provided descriptions and data

upon the nature of land ownership, cultivation techniques, cropping systems and fallow periods,

and basic productivity within traditional subsistence subsidised by cash-cropping (Maude 1965;

6

Thaman 1976). This data is important, but cannot be assumed to accurately represent the nature

of production throughout Tongan prehistory. The lack of diversity within modern production on

Tongatapu required data collection from other Pacific dryland systems, to be able to model

potential changes in yield and labour inputs resulting from varying cultivation techniques

targeting different ranges of crops. Five systems from the Western Pacific were chosen, to

provide a range of comparable data. They are the Gadio Enga of the New Guinea Highlands

(Dornstreich 1977), Tongatapu (Ministry of Agriculture and Forestry 2001), Bellona Island

(Christiansen 1975), Ontong Java (Bayliss-Smith 1973, 1977, 1986) and Anuta (Yen 1973b) in

the Solomon Island Outliers. Data was collected on the range of plant species cultivated within

each system, and the labour inputs and yields for each of these. These figures were used to

calculate basic efficiency or rate of return ratios for each of these species in terms of nutritional

and yield outputs to labour investment inputs, and to model archaeologically identified species

within a range of different environmental, social and economic contexts. The geographic scale

of each of these systems varied, but efficiency ratios are used to ensure comparability across all

systems. Each system was characterised according to these variables (species diversity,

nutritional diversity, labour diversity, and yield ratio diversity) rather than using loaded

terminology such as ‘broad spectrum’ or ‘intensive’ that often does not capture the range of

production techniques, decision-making and energy investment within different agro-

ecosystems.

To model agricultural development in Tongan prehistory, it was deemed appropriate to

keep the range of assumptions minimal to reduce the potential for error. Therefore an

assessment of productivity was conducted through characterisation of archaeobotanical datasets

using the ranges of yield and labour figures recorded from modern systems. Productivity is only

one variable within an agroecological approach to production, but it can be placed within the

social, ecological and economic context of each system to discuss how the range compared with

expected outcomes based on previous research. It is clear that demographic, climatic and social

factors would have impacted both the scale and intensity of agricultural production in the past,

but these impacts can only be hypothesised within current research. The approach taken within

this thesis therefore aimed to keep modelled assumptions to a minimum and redirect the focus

of agricultural development away from the scale of production, towards a discussion of

decision-making based on system nutritional efficiency and founded on data highlighting the

timing of crop introductions and their use.

Thesis organisation

This study of agricultural development in Tongan prehistory is broken down into two main

components related to the objectives of this research. After a brief review of Tongan agriculture

within the Pacific context (Chapter 2), the first component will focus on the development of a

comparative collection of micro- and macrobotanical remains for Tonga. Chapters 3 and 4

7

assess the feasibility of applying the analysis of starch and vegetative parenchyma to questions

regarding diet and subsistence. The biology, morphology, taphonomy and contamination

potential of each of these remains was reviewed in order to gauge both the preservation and

identification potential of archaeobotanical material. Chapter 5 outlines the methodology to

create a reference collection for this study including species selection, field collection, and

laboratory processing. Sample preparation for imaging using light microscopy and Scanning

Electron Microscopy (SEM) is described, and the collection of morphometric data through the

use of image analysis software. Finally, tools such as replicable multivariate statistical

classifications and identification keys are provided that characterise the morphology of starch

and vegetative parenchyma and will enable the identification of unknown samples from

archaeological deposits. The development of this comparative collection will enable the key

research questions concerning the role of plants within the colonising process and the

development of social hierarchy in the Tongan archipelago to be addressed.

The second component of this thesis deals with the application of micro- and macro-

botanical techniques within archaeobotanical research on Tongatapu to provide a chronology for

crop introductions and agricultural development. Chapter 6 introduces the three sites selected

for analysis, Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2), and details the methods

employed to excavate and extract archaeobotanical remains from cultural deposits. The

establishment of laboratory protocols for the extraction and analysis of both starch and macro-

botanical remains such as charred endocarp and parenchyma is explored in Chapter 7. This

borrows from and also builds on the range of protocols already used in archaeobotanical studies

in the Pacific region. The results of extraction and identification processes from the three sites

are outlined in Chapter 8, along with the cost-benefit analysis of five comparative plant

production systems from the Western Pacific and the archaeological production systems from

each site. Chapter 9 discusses the characterisation and modelling of data from each of the

archaeological sites included in this study. The feasibility of modelling past production systems

using a Human Ecological and Agroecological approach is discussed, along with a comparison

of the expected and modelled outcomes of analysis and how modelled production can be tied to

social complexity. Chapter 9 also discusses the timing of individual crop introductions into

Tonga using the data provided within this study and a new chronology for agricultural

development in Tongan prehistory is outlined. Chapter 10 concludes this thesis with a summary

of the outputs of this research: the development of a comprehensive comparative collection for

Tonga that has applications for the wider Pacific, and an alternative perspective on agricultural

development in Tonga based on proxy and direct evidence for crop cultivation and use.

Recommendations for future research that will build on these outputs through further

application of archaeobotanical techniques such as starch and charred parenchyma analysis

within research in Tonga and Pacific region is also highlighted and emphasis is placed on the

8

potential contribution these remains can make towards answering questions about diet,

subsistence and social complexity in prehistory.

9

Chapter 2 Tongan Agriculture in the Pacific

Context

Research to date

Research into Tongan prehistory has thus far been oriented towards the study of artefacts and

faunal remains. Although a range of archaeological and ethno-historic research has already been

carried out in Tonga, none of these studies have so far addressed the role of agricultural change

within cultural development in the island group. Early research was directed towards gathering

information about the first colonisers, known as the Lapita culture, who had made their way

from Southeast Asia into Melanesia and finally into Western Polynesia by 2800 BP (Burley

1998:349; Burley and Connaughton 2007; Burley et al. 2001). Very little is known about the

role of horticulture within Lapita subsistence, especially in Western Polynesia. However, there

are numerous studies of the wild food components of colonising diets such as shellfish, birds,

reptiles and fish (Burley 1998; Burley and Connaughton 2007; Burley and Dickinson 2001;

Groube 1971; Kirch and Dye 1979; Poulsen 1987; Spenneman 1986, 1989; Steadman, Pregill

and Burley 2002). Archaeologists have been divided over whether a ‘strandlooper’ economy

was employed that focussed on the collection of these natural coastal resources (Best 1984;

Groube 1971); or a subsistence dominated by well-developed agricultural practices (Green

1979; Kirch 1997). The interpretation of the archaeological record is biased towards marine-

based foraging due to the dominance of midden remains within Lapita cultural deposits

(Davidson 1979:93; Davidson and Leach 2001), and current evidence suggests that agricultural

activities were initially of only secondary importance (Burley 1998:355; Poulsen 1987:253-5;

Spenneman 1989).

The signature dentate-stamped pottery has become the cultural marker for the Lapita, but after

2650 BP a trend of undecorated pottery (Plainware) can be seen in the archaeological record

(Burley 1998:359). This is viewed as part of the development of Western Polynesian culture

within Tonga, and was part of a suite of changes that also included expansion further inland and

into off-shore islands. Kirch (1984) argued that expansion was an indication that population

density also began to increase dramatically. Kirch calculated that roughly all of the arable land

on Tongatapu would have come under agrarian use between one to two millennia after

colonisation (1984:222). These, and earlier calculations were based on agricultural practices

involving shifting cultivation with relatively short fallow periods, as recorded by ethnographers

after European contact (Beaglehole and Beaglehole 1941; Green 1973). During this same

period, after 2650 BP reliance on lagoon-based marine resources such as shellfish also

decreased markedly (Spenneman 1989).

10

Between 1500 BP and around 750 BP, very little is known about Tonga’s past. Oral traditions

and genealogy suggest that the first Tu’i Tonga was appointed at around 1000 BP, although

evidence of a widespread and integrated maritime chiefdom within the archaeological record is

difficult to confirm prior to 500 BP (Burley 1998:375). Janet Davidson coined the term ‘the

Dark Age’ for this gap, citing the lack of archaeological sites until late in the first millennium

AD when monumental architecture associated with the development of a complex chiefdom

emerges (Davidson 1979:94-5). More is known about the Tongan maritime chiefdom after 750

BP and the control of land by this central polity based on Tongatapu (Burley 1998; Clark et al.

2008). A complex social hierarchy existed at European contact, culminating in three paramount

chiefly titles known as the Tu’i Tonga, the Tu’i Ha’a Takalaua, and the Tu’i Kanokupolu lines.

To date, there is currently no direct archaeological evidence for agriculture in Tongan

prehistory. Historical linguistics indicates a Proto-Oceanic lexicon containing the basic suite of

Oceanic cultigens (Kirch 1997:206-207), which is assumed to have been transported throughout

Western Polynesia by the Eastern Lapita cultural complex. Thus it is inferred that the Lapita

colonisers had an economy in which agriculture played some continued role. In the late 18th

century the Tongan language had names for a wide range of root and tree crops, although the

core cultigens grown were yam (Dioscorea alata), giant taro (Alocasia macrorrhiza), taro

(Colocasia esculenta), sweet potato (Ipomoea batatas), coconut (Cocos nucifera), plantain and

bananas (Musa spp.), and breadfruit (Artocarpus altilis) (Burley and Connaughton 2007:182).

Ethno-archaeological observations have been made of multi-cropping using intensive dryland

field systems that are suited to the high limestone islands and lack of streams for irrigation

(Kirch 1984). Agricultural features related to these systems, such as stone structures, can also

still be seen in some locations in the Tongan landscape. Although field systems have been

mapped on the outer islands, such as Niuatoputapu (Kirch 1988), no radiocarbon dates are

associated with these features. Based on this information, it has been assumed that a changing

environment, population increase and subsequently reduced food returns forced post-Lapita

Tongan populations to rely more heavily on horticulturally produced food, eventually

manifesting in an increasingly hierarchical society (Spenneman 1986:3).

Geographic and climatic limitations to agricultural modelling

The Kingdom of Tonga comprises more than 170 islands within the South Pacific Ocean, and is

located from 15°30’ to 22° 20’ S latitude and between 173°00’ and 177° 15’ W longitude. The

islands formed on the crest of the Tongan Ridge, bordering the Tonga Trench at the Pacific

Plate Boundary (Roy 1990). Tongatapu is within the southern block of this ridge and is made up

of Pliocene and Pleistocene limestone that reaches a maximum height of 65-70m above sea

level in the southeast, and is little above sea level in the northwest due to a tilt in topography. As

a result, the southern windward shores are composed of near-vertical cliffs and represent the

most rugged topography on an island that is largely flat to gently undulating (Roy 1990; Maude

11

1965; Thaman 1976). There are no permanent streams on the island; free-draining porous soils

above the limestone geological base which enable water to travel to the sea through

underground channels. The location of the island of Tongatapu near the Tropic of Capricorn

results in a mean annual temperature of around 23°C, humidity of up to 79%, and mean annual

rainfall of 187cm (Thaman 1976). Seasonal variation in temperatures is low, only fluctuating by

4°C, but rainfall varies from around 8.4cm in the driest months to 24cm in wet months;

however, there can be considerable variability in rainfall from year to year. Whilst there are

some seasonal and annual fluctuations in climatic conditions, these do not vary significantly

across Tongatapu due to the absence of significant topographic differences.

The geography and climatic conditions on Tongatapu both aid and hinder the modelling

of past production systems. Unlike the Hawaiian archipelago, where dryland agricultural

systems are often constructed and managed within distinct ecological zones (Lincoln and

Ladefoged 2014), the raised limestone island of Tongatapu has little variety within ecological

niches and so has no distinguishable boundaries for the utilisation of diverse production

techniques (Maude 1965). One of the only observed variables affecting the geographic

distribution of crop production is soil type. Two main soil types are present within the

archipelago, the kelefatu soils which are very friable and fertile volcanic soils and vary in

texture from loamy sand to clay, and the tou’one sandy soil that is present at low elevations

close to the sea (Maude 1965; Thaman 1976). Tongatapu has both of these, but the kelefatu is

the most prevalent- covering 90% of the landmass. Yams (Dioscorea spp.) do not grow well

within small areas of tou’one soils; the sandy fast-draining soils are instead better suited to the

cultivation of sweet potato (Ipomoea batatas). Gibbs (1967) distinguished two sub-categories

between the upland or kelefatu soils. The first of these, ‘Lapaha clays’ are predominant in

Eastern Tongatapu and around the capital Nuku’alofa. The other, ‘Vaini clays’ cover most of

the uplands in the west. The two soils are very similar in texture and composition yet cultivators

in modern times understand the differences in fertility resulting from use and manipulation of

these soils, and the limitations of particular cropping and fallow practices within these (Maude

1965). It is therefore possible that almost all of the available arable land on Tongatapu, around

224.14km² or 55398 acres, could be cultivated using much the same shifting dryland

agricultural techniques, at any point in time. Early censuses estimate that around 7, 308 people

were living on Tongatapu by 1891(Burley 2007), while estimates for pre-contact populations for

the whole archipelago vary from 29700 (Maude 1965) to 40000 (Kirch 1984, 1988).

These two sets of data (geographic variation and historic population figures) have been

used to model carrying capacity during Tongan prehistory by Green (1973; Bayliss-Smith

1978), where populations were supported by per capita acreages of 1.6-2.0 depending on high to

low intensity production. The standard populations were calculated for these intensity levels and

varying proportions of arable land under cultivation, and suggest that under the most intensive

12

system (1.6 acres per person) the entire arable land could have supported 346200 people (Green

1973:70). Based on these figures, and ethnographic descriptions of cultivation systems within

the landscape on Tongatapu, Green argues that the best population estimate for the 18th century

would have been 15000-17000, under conditions of 1.8-2.0 acres per capita in a cultivation

cycle of 8-10 years through bush fallowing agriculture (1973:72). Furthermore, this figure could

easily have been attained up to 1000 years before, but this does not indicate that the population

reached this peak and then stayed at this level. Instead, Green (1973:73) suggests that following

this peak the pressure on land and resources triggered reduction mechanisms such as warfare to

restrain further growth. Green also argues that reduction mechanisms do not necessarily begin

after carrying capacity has been reached, but instead when figures of closer to 60-80% capacity

are attained. These figures set an upper limit on population on Tongatapu of between 18,000 to

24,000 people and suggest population may have been higher in the past than at contact.

More recently, Burley (2007) modelled population estimates for the three key phases in Tongan

prehistory (Lapita, Plainware and Classic Chiefdom). Previous estimates (Green 1973; Kirch

1984; Maude 1965; Walsh 1970), settlement patterns and analysis of material culture (Burley

1999; Spenneman 1987) were utilised to predict the likely rate of population increase over time.

Given a founding population of around 100 people, a conservative population growth rate of

0.003, and a need for approximately 2 acres of productive land per person, the population at the

end of the Lapita period within the archipelago could have been as high as 600-700 people

(Burley 2007). Later during the Plainware and Ancestral Polynesian phases, around half the

projected maximum land could have been under production with agricultural field systems by

AD 400, which may have stimulated long-distance voyaging and exchange networks further

east. Finally late prehistoric populations were predicted to have peaked around 18, 467 on

Tongatapu alone (Burley 2007). The difference between past estimates and these recent figures

indicate that there are varying opinions upon the potential agricultural productivity of land on

Tongatapu, rates of population growth, as well as the acreage needed to support increasing

populations.

Ethno-historic accounts of plant cultivation in Tonga:

Early explorers and missionaries have provided vital details about Tongan subsistence practices

at European contact. Most relevant to this study are descriptions of land tenure, and the

cultivation of crops within the plantations they encountered throughout the archipelago. In

addition, these sources mention the most important economic species including cultigens and

wild species that were made use of in times of famine or hardship. The list of crops witnessed

by Le Maire in 1616 (1967), Abel Tasman in 1643 (1776), Cook in 1773 and 1777 (in

Beaglehole 1969; Cook 1785), La Perouse in 1788 (1799), Labillardiere in 1793 (1800), Wilson

(1799), Mariner in 1791 (Martin 1991), Waldegrave in 1830 (1833), Hemsley (1894), Gifford

(1929), Beaglehole and Beaglehole (1941), and others on Tongatapu, is vital to the development

13

of a comprehensive understanding of late prehistoric and contact period agriculture in Tonga. It

is also possible with such information to assess the temporal changes in reliance on certain

crops. Other researchers have established the value of using ethnographic data as a guide to

understanding the past (David and Kramer 2001, Wylie 1985). Ethnohistoric information is used

in this thesis to create baseline data for the selection and development of a comparative

collection in this study, as well as generating a picture of the environmental and social limits of

production in Tonga under the Tu’i Tonga chiefdom in the historic period.

Plantations

Information can be gathered from these sources on the nature and organisation of agricultural

plantations, within which the majority of cultivated crops were grown. Importantly, early

observers also commented on the division of land and production according to status

differentiation. The first European explorer to reach Tongatapu was Dutch explorer Abel

Tasman in 1643 (1776), followed by Cook in 1773 and again in 1777 (in Beaglehole 1969;

Cook 1785). Tasman (1776), having observed the bounty of Tongatapu through gifts and trade

of pigs, poultry, coconuts, plantains, bananas, yams and other roots, went onshore and noted the

layout of plantations in neat squares within which these crops were cultivated. During his

second voyage in 1773, Cook (in Beaglehole 1969; Cook 1785) explored the islands within the

Vava’u, Ha’apai and Tongatapu groups, and described his encounters with the islanders and

excursions onshore. Cook, his officers, and onboard naturalists commented extensively on the

distribution of plantations across the various islands, and the nature of the crops being cultivated

(Cook in Beaglehole 1969; Cook 1785). On the main island of Tongatapu, Cook (1785)

observed the layout and functional divisions within the individual plantations. The botanical

knowledge of a naturalist on d Entrecasteaux’s voyage to the Vava’u Group, Jacques

Labillardiere (1800), enabled the accurate identification and description of the various crops

within these plantations, along with their domestic or economic purposes. On the larger island

of Tongatapu, multi-cropping seemed to be the common method of cultivation within the

individual plantations, whereby a variety of food plants are grown together within plots.

A surgeon and naturalist on Cook’s second and third voyages, Mr Anderson, travelled more

extensively inland from the coast of Tongatapu and made further notes upon the distribution of

cultivated areas. Eastward of their base near the Fanga ‘Uta lagoon, there was a lack of

uncultivated land for nearly two miles (Anderson in Cook 1785:288). However, further west

most of the country was composed of fenced plantations (1785:314). Johann Reinhold Forster

was another naturalist on Cook’s second voyage whose journals, alongside those of his son

Georg, described the cultivation of fruits and vegetables within organised plantations (Forster

1777, 1778). Georg noted that the coral rock, thin soils and lack of groundwater ensured that

those inhabiting Tongatapu were, in his opinion, forced to labour more greatly than the

Tahitians to produce food (Forster 1777). He argued that this accounted for the regularity of the

14

plantation distribution, and the accurate division of land (Forster 1777). Johann (Forster

1778:223) also observed that the whole of Tongatapu was highly cultivated and seemed to be

private property, the boundaries of which were fenced. Tree crops also commonly bordered or

divided plantations (La Perouse 1799:171).

Cook (in Beaglehole 1969) noted that there were differences between the produce of the

plantations reserved for the chiefly elite or ‘first rank’, and the commoners. Similarly, Captain

Wilson (1799) commented on the links between land tenure arrangements and the layout of

individual plantations. A map was produced from the circumnavigation of Tongatapu,

highlighting the occupied and cultivated areas of the island, and the traditional names for these

locations. Wilson also noted the use of the term ‘abey’ [abi] for these plantations or plots of land

(Wilson 1799:101), which is still in use today but under different tenure conditions.

Land tenure

Complex social hierarchy controlled the division and use of land for agriculture on Tongatapu in

the 18th and 19th Centuries. Accounts from this period describe how this status differentiation

resulted in different conditions for land ownership. These details are essential for reconstructing

the influence that the state-level social hierarchy may have had on crop introductions and

associated horticultural production in the past. Captain Waldegrave (1833) was informed during

his visit in 1830 that the island was divided into 13 portions, with a chief being the proprietor of

each. He was told that chiefs could, and often did, displace residents on the land, and these

chiefs retained a claim to a portion of the agricultural produce (1833:185). This portion was

argued by Waldegrave to be claimed in the absence of an official ‘taxation system’. In addition,

the kings and higher chiefs reserved a portion of the land itself for their own agricultural

production. E. W Gifford spent around nine months in Tonga as a member of the Bayard

Dominick Expedition of Bernice P. Bishop Museum in 1920–21. Gifford noted that in the past

all land and its products were regarded as the property of the Tu’i Tonga (Gifford 1929:102).

Within these lands, those within the domain of the Tu’i Kanokupolu were regarded as his

property, but also subject to the demand of the Tu’i Tonga. Likewise, a similar relationship was

continued between the lesser chiefs and the Tui Kanokupolu. Both Cook (1785) and Mariner (in

Martin 1991) noted similar arrangements. Gifford also argued that there seems to have been no

communal lands in Tongan prehistory, but at the time of his visit there were some clear

examples of modern communal tenancy (1929:176). On Lifuka Island, a particular tract of land

or api belonged to the Queen, but in 1920 it was used as a communal field by the inhabitants of

the village of Pangai, each household having a small section to plant sweet potatoes (1929:176).

During harvesting, a portion was then given in return to the Queen.

All vegetable and animal products within the territory directly controlled by the Tu’i

Kanokupolu were tapu, or off-limits, for anyone but that high chief (Gifford 1929:104). Two

15

petty chiefs were appointed to continuously check that the common people were not utilizing

those products without permission. The titles of these positions were the Tu’i Pangai and the

Tu’i Sinoieiki. During their rounds of the territory, these officers would mark fine bunches of

cooking bananas, breadfruit, yams, sweet potatoes that were suitable for the Tu’i Kanokupolu,

by putting a sharp stick into the base of the tree or hanging coconut leaves from the branches

(1929:104; Mariner in Martin 1991). In the case of yams or sweet potatoes, a stick was placed

into the ground near the crops. These officers also reported to the chief and through him to the

Tui Kanokupolu, upon the amount of crops planted by the farmers, and whether or not they

were sufficient. However, this only applied to the territory of the Haa Ngata Motua lineage. A

range of terms for other roles within Tongan society were also recorded by Gifford. For

example, ‘pule fonua’ was the name for the rulers of the land, or chiefs who control food supply

(1929:104).

Festivals

Related to these intricate systems of land ownership was a yearly pattern of feasting and tributes

based on the produce of plantations. According to early accounts, these were important for the

redistribution of food surpluses and reinforced the ownership and land and production by elites

within Tongan society. The first fruits of the yearly yam harvest or the first of any catch of fish

or other food had to be presented to the chief and to the Tui Tonga before it could be partaken of

by the producers (Gifford 1929:103). Tributes were carried from as far afield as Vava’u. A

select group of people were appointed as petty officers in charge of supplying these food articles

to the Tui Tonga, behind which Gifford believes is a form of religious sanction (1929:103).

These tributes were “virtually made to the gods, but were made to them through the Tui Tonga

who was treated like a god” (1929:103). William Mariner was a resident upon the island of

Tongatapu for several years from 1806 to 1810, and recounted his experiences to John Martin

which were originally published in 1817. During this time, he observed the cultivation of

breadfruit, coconuts and yams on a daily basis, and so could provide detailed descriptions of

horticultural practices throughout the seasons. He witnessed the ‘First fruits’ or ‘inasi ceremony,

and perceived these offerings of the early yam harvest to be a means of insuring the

“…protection of the gods and productions of the earth, of which yams are the most important.”

(Mariner in Martin 1991:381)

In preparation for the ceremony, a particular variety of yams were planted about a month before

the regular crop (Mariner in Martin 1991:381), most likely those described today as the ‘Early

yam’. As soon as this crop arrived at a certain state of maturity, a message was sent to the Tui

Tonga that the yams are fit to be harvested. The Tui Tonga then appointed a day for the

ceremony— usually around 10 days later. The day before the ceremony the yams were dug up

and wrapped in Pandanus leaves, and other provisions such as fish, kava root and mahoa

(arrowroot) are prepared (Mariner in Martin 1991:382). On the day of the ceremony the harvest

16

was brought to the malai or meeting place of the chief of the plantation, and then the procession

carried onto the grave of the last Tui Tonga to receive a ‘blessing’, before returning to the malai.

The yam harvest was then divided into portions. Half was allocated to the king, one quarter was

dedicated to the gods and so appropriated by the priests, and the remainder was given to the Tui

Tonga (Mariner in Martin 1991:382). Mariner thus commented on the generosity of the Tongan

people, particularly those of the lower ranks, whereby it was “…so much the custom of Tonga

to make liberal and profuse presents that the people generally either feast or starve.” (Mariner in

Martin 1991:385)

In addition to the ‘inasi festival, several other ceremonies were carried out during the harvests to

ensure productive success. Mariner describes the ‘tow-tow’ [tau tau] ceremony whereby

offerings of yams, coconuts and other vegetable produce was made to A’lo A’lo, the god of

weather, in particular but also to other gods (Mariner in Martin 1991:385). These concessions

were made for the purpose of ensuring a continuation of favourable weather and soil fertility.

The ceremony was performed initially when the yams were approaching maturity in early

November, and then repeated every ten days seven or eight times. The produce was piled into

three mounds, one of which was given to the gods and the remaining two were given to the

chiefs and their households. After the ceremony, the pile dedicated to the gods was then divided

between the attendees of the festivities. Another form of feasting was the ‘pongipongi’ which

involved the presentation of food and kava to the Tu’i Kanokupolu by chiefs of the Haa Ngata

Motua and Haa Hatea lineages several times a year (Mariner in Martin 1991:99). In general, the

Tu’i Kanokupolu was regarded as the ‘working king’ who oversaw the planting and other

activities for the high king or Tu’i Tonga (Gifford 1929:99). The first Tu’i Kanokupolu Ngata

was sent to Hihifo by the Tu’i Haa Takalaua to supervise agriculture and fishing, passing the

produce to the Tu’i Haa Takalaua, then to the Tu’i Tonga, and the tradition continued until the

independent powerbase in Hihifo eventually overthrew the Tu’i Tonga.

Cropping cycle

Importantly for this study, a small number of European explorers and scientists also commented

on the seasonality and production techniques used to cultivate and harvest crops produced

within these plantations on Tongatapu. These shed light on the restrictions upon production of

annual crops such as taro (Colocasia esculenta) over perennial tree crops such as breadfruit

(Artocarpus spp.) or bananas and plantains (Musa spp.). Anderson (in Cook 1785) argued that

the tropical climate of Tonga would have resulted in a fast turn-over of crops within the

plantations. He commented:

The quick succession of vegetables has been already mentioned; but I am not certain that

the changes of weather, by which it is brought about, are considerable enough to make

them perceptible to the natives as to their method of life, or rather that they should be

17

sensible of the different seasons. This perhaps may be inferred from the state of their

vegetable productions, which are never so much affected, with respect to the foliage, as to

shed that all at once; for every leaf is succeeded by another, as fast as it falls, which causes

that appearance of universal and continual spring round here. (Anderson in Cook

1785:330).

Likewise, Cook himself described the difference in production between his visits. It was noted

that the stocks were replenished despite arriving back again sooner than expected, but the

breadfruits which had been the only original produce available for purchase were replaced with

yams and plantains (1785:272). Large areas that had been fallow previously were transformed

into plantain fields. These observations demonstrate the relatively quick succession of the

seasons, in terms of the vegetables produced on Tongatapu at different times of the year (in

Beaglehole 1969). Seasonal fluctuations were also commented on by La Perouse (1799:171),

who thought that the low islands in this group likely experienced drought at some stage during

the year and commented on the necessity of watering fields. In contrast, on the island of Uoleva

further north in the Ha’apai group, water sources enabled irrigation.

Summary

From these various accounts, it is clear that some crops were used consistently from first

European contact in the mid 18th century, right through until the early 20th century. The staple

cultigens included Elephant ear taro (Alocasia macrorrhiza), breadfruit (Artocarpus altilis),

coconut (Cocos nucifera), taro (Colocasia esculenta), winged yams (Dioscorea alata), the lesser

yam (Dioscorea esculenta), sweet potato (Ipomoea batatas), plantain and bananas (Musa spp.),

and Polynesian arrowroot (Tacca leontopetaloides). Other fruits, nuts and tubers were also

cultivated to some degree and supplemented these crops. These included the shaddock (Citrus

maxima), turmeric (Curcuma longa), melons (Cucumis melo), Tahitian chestnut (Inocarpus

fagifer), Indian mulberry (Morinda citrifolia), pandanus (Pandanus tectorius), kava (Piper

methysticum), sugarcane (Saccharum officinarum), Otaheite apple (Spondias dulcis), Malay

apple (Syzygium malaccense), and the tropical almond (Terminalia catappa). Finally, a small

range of naturalised plants were utilised for their edible fruits and tubers such as bitter yam

(Dioscorea bulbifera), the giant swamp taro (Cyrtosperma merkusii), and the stink lily

(Amorphophallus campanulatus). The majority of these crops in the proto-historic era were

grown in plantations that surrounded small villages. Each household usually had the use of an

individual plantation for their own subsistence needs, however the land itself could be owned by

the chief or higher chiefs such as the Tui Kanokupolu or Tui Tonga (Gifford 1929:102,

Waldegrave 1833:185). The land belonging to these chiefs was monitored by several officers

appointed by the person holding one of these titles, and crops could be allocated to them upon

maturation and harvesting (Gifford 1929:104). Related to these systems of land ownership was a

18

yearly pattern of feasting and tributes that were brought from as far afield as Vava’u (Mariner in

Martin 1991:385).

The internal organisation of plantations varied, depending on the individual tastes and choices

of the households utilising them. However, most households relied heavily on yams, multi-

cropping them with sweet potato and taro in mounds in the centre of plantations (Beaglehole

and Beaglehole 1941:43-44, Gifford 1929, La Billardiere 1800:366). Arboricultural crops such

as plantains, bananas, and breadfruit were grown bordering the outer limits of the plantations

(La Billardiere 1800:378, Wilson 1799:240). These trees were often left to mature and harvested

each season as the fruits ripened, while the tuberous plants were replanted until the soil in the

plot could no longer sustain growth and the plot was abandoned for a time (Cook in Beaglehole

1969; Cook 1785:271-2). After the introduction of new crops by European settlers such as

manioc and corn, agricultural practices were forced to change to suit the requirements of these

cultigens and there was a reduced reliance on traditional cultigens (Beaglehole and Beaglehole

1941). Despite this shift, these crops recorded by European explorers in the 18th and 19th

Centuries mostly continue to be grown today.

These ethnohistoric details provide essential background information to meet the two main

objectives of this thesis. The lists of species recorded within early accounts provided baseline

data for the construction of a comprehensive reference collection of economic and

supplementary plants used in Tongan prehistory. Likewise, the descriptions of production

techniques, plantation layouts, feasting and tribute systems form a picture of agricultural

production in the proto-historic period at the height of the state prior to European influence.

These details enable some insight into the efficiency of this system in both productive and social

terms, and against which past systems can be compared to link production to social complexity.

19

Table 2.1 List of species recorded in early ethno-historic accounts from Tonga.

Species

Tasman

1643

Cook

1773-77

Forster

1773

Perouse

1780s

Labillardiere

1793

Wilson

1797

Mariner

1817

Orlebar

1830

Waldegrave

1833

Gifford

1929

Beaglehole

1938

Alocasia macrorrhiza X X X

Amorphophallus paeoniifolius X

Artocarpus altilis X X X X X X X X X X

Benincasa hispida X

Broussonetia papyrifera X X X X X

Citrus maxima X X X X

Cocos nucifera X X X X X X X X X X X

Colocasia esculenta X X X X X X X

Cordyline fruticosa/terminalis X

Curcuma longa X X

Cucumis melo X

Dioscora alata X X X X X X X X X X

Dioscorea bulbifera ? X ?

Dioscorea esculenta X ? X ? X

Ficus tinctoria X

Hibiscus manihot X

Inocarpus fagifer X X X

Ipomoea batatas X X X X

Morinda citrifolia X

Musa sp. (bananas) X X X X X X X X X X X

Musa sp. (plantains) X X X X X X X

Pandanus tectorius X X X

Piper methysticum X X X X X X X X

Pritchardia pacifica X

Saccharum officinarum X X X X X X

Spondias dulcis X X X

Syzygium malaccense X

Tacca leontopetaloides X X X

20

Archaeobotany of cultigens in the Pacific

The discussion of agricultural change in Tongan prehistory is the product of the direction of past

research, rather than a paucity of evidence for this floral element of subsistence within the

Tongan archaeological record. Microfossil research in other locations has demonstrated the

applicability of this analysis towards identifying the presence of crops and the nature of their

use within archaeological contexts (Fullagar et al. 1998, 2006; Horrocks et al. 2004; Horrocks,

Grant-Mackie and Matissoo-Smith 2008; Loy et al. 1992; Piperno 2009; Summerhayes at al.

2010, among others). Similarly macrobotanical analysis has been used to provide direct

evidence of plant cultivation and domestication in the New and Old Worlds, and the Indo-

Pacific (Fuller 2007; Oliveira 2008; Paz 2001; Thompson 1994; Ugent et al. 1981).

Unlike archaeological investigations in the Old World, archaeobotanical techniques

have not been consistently applied in the Pacific region. This is due to several factors. The first

of these is that the preservation of plant remains in tropical climates is more variable than in the

cooler or arid northern latitudes (Paz 2005). Second, the agricultural practices of most

prehistoric Pacific communities revolved around the production and consumption of starchy tree

nuts, roots and tubers, rather than small seeds such as wheat or rice which have been the

traditional focus of archaeobotany (Hather 1994:51). Finally, many of the main domestic plants

such as taro (Colocasia esculenta), bananas (Musa spp.), and breadfruit (Artocarpus spp.) are

not genetically or phenotypically identifiable from wild populations (Fairburn 2005a).

Consequently, archaeobotanical investigations in the tropics have often been based on chance

finds (Paz 2005; Glover 1979). Recently, rock shelters, caves, and waterlogged sites have

provided new site types for the preservation of plant remains in tropical climates (Glover 1979;

Oliveira 2008; Paz 2001, 2005; Fairburn 2005a). Analysis of those remains that have been

recovered have suggested that many tropical plant production systems are a poor fit within the

traditional typologies of foraging or farming using wild or domestic species, and so the whole

global system of agricultural classification has subsequently come into question (Fairburn

2005a).

These technical and theoretical issues have complicated the interpretation of plant use

within the archaeobotanical record in the Pacific. Here, the goal is to review the antiquity of

plant use within the Pacific economy, through focusing on the identification of macro- and

microbotanical remains of edible root, tuber, and tree crops. Clearly domestication cannot be

sufficiently discriminated from crop use through morphological or genetic variability within

most of these longer-lived taxa, therefore the history of edible plant use from Island Southeast

Asia, through Near Oceania to Remote Oceania will be assessed in terms of the archaeological

contexts from which these plants were identified and the timing of their use. As much as

possible archaeobotanical data, whether chance or systematic finds has been incorporated into

21

the review. Through this, a chronology of plant introductions in the Pacific economy will be

developed.

Pleistocene: Independent origins for cultivation?

Of the suite of crops that now dominate agriculture in Tonga, including a number of aroids and

yams, many have now been proven to have been first adopted for use within the terminal

Pleistocene in Near Oceania, rather than brought during the mid-Holocene by Austronesian

speakers from Island Southeast Asia. This review will therefore begin within New Guinea,

discussing evidence for the incorporation of root, tuber and tree crops into subsistence before

tracing plant use east to Remote Oceania. It will also be acknowledged that this was not a

unilinear movement, and that some of these same crops were also incorporated into pre-

agricultural diets further west, indicating that plants were also being carried in the opposite

direction.

The earliest evidence for the adoption of root, tuber and tree crops that comprised

significant components of the Pacific economy prior to European contact is in the New Guinea

highlands. Dioscorea yam starch residues found on stone artefacts and charred Pandanus have

been recovered from Joes Garden, Kosipe Mission and dated to over 40,000 BP using

Themoluminescence (TL) dating (Summerhayes et al. 2010). Large amounts of

archaeobotanical data have also been collected from years of excavations at Kuk Swamp.

Within the various phases of occupation at the site, microfossils in the forms of phytoliths,

starch and pollen of known edible cultigens have been identified and interpreted as evidence for

the beginning of cultivation and manipulation of these taxa (Denham 2007; Denham et al. 2003,

2004; Donohue and Denham 2009; Golson 2007; Wilson 1985). Whether these starch-rich

plants were incorporated into an existing highland subsistence system or introduced from lower

elevations as part of a new system during the early Holocene remains unproven due to a lack of

contemporary data from the New Guinea lowlands (Golson 2007). The Kuk sequence has been

divided into several phases, the first two of which have been dated to the Pleistocene and early

Holocene.

Phase 1 (10,200-9910 BP) represents the earliest evidence of plant exploitation within

the upper Wahgi Valley at the wetland margin (Denham 2007:79). A palaeosurface consisting

of pits, runnels, stake and post holes arguably representing wetland management for cultivation

of corms and tubers (Denham 2007; Denham et al. 2003, 2004; Hope and Golson 1995) is

contemporaneous with stone flakes and grinding stones that contain starch residues of taro

(Colocasia esculenta) and a variety of yam (Dioscorea sp.) (Fullagar et al. 2006). Additionally,

seed phytoliths of the Eumusa section of bananas, particularly Musa acuminata morphotypes,

were extracted from sediments below Phase 1, suggesting the presence of this wild variety of

Musaceae within the landscape prior to human occupation (Denham 2007; Denham et al. 2003;

22

Wilson 1985). Phase 2 (6950-6440 BP) has been argued to represent the first unequivocal

evidence for deliberate planting at Kuk Swamp. This comprised of multi-cropping mounded

cultivation of Colocasia taro and Dioscorea sp., most likely Dioscorea alata or Dioscorea

pentaphylla, with Musa spp. and was confirmed through further residue analysis of artefacts

combined with locally elevated frequencies of Musa phytoliths in sediments (Denham 2007;

Denham et al. 2003; Fullagar et al. 2006). In total, over 30 edible plants were identified from

archaeobotanical and palaeoecological investigations in the upper Wahgi Valley. The early to

mid Holocene data collected from excavations at Kuk Swamp have since been interpreted to

indicate that Musa acuminata sp. banksii was first domesticated or deliberately cultivated in

New Guinea, along with the independent domestication of Colocasia esculenta and Dioscorea

alata (Denham 2007; Denham et al. 2003, 2004; Donohue and Denham 2009; Golson 1989,

2007).

Other early archaeobotanical data from Island Southeast Asia, New Guinea and Near

Oceania appears to support these arguments for pre-agricultural transport of species, or

alternatively that the natural dispersal of the immediate ancestors of crops such as various aroids

or Canarium predated human settlement of the region (Yen 1993). Haberle (1994, 1995)

identified Colocasia pollen from a sediment core in Lake Wanum in lowland New Guinea at

around 9000 BP, but argues that this only identifies the presence of this species within the

landscape rather than indicating gardening activity. Similarly, Colocasia and possibly Alocasia

taro has been identified within starch, calcium oxylate crystal and cellulosic tissue in residues

on stone tools from Kilu Cave in the Solomon Islands from 28,000 BP (Loy et al. 1992),

indicating exploitation of these taxa in the Pleistocene. Loy and others (1992:910) argue that the

implications of this and other data suggest that the northern Solomons and Australia should be

included within the natural distribution of these aroids. Further west in Malaysia, research at

Niah Cave has demonstrated that Dioscorea alata and cf. Dioscorea hispida were exploited

around c. 40,000 BP through fragments of charred parenchyma and starch granules (Barton and

Paz 2007:60-62). Fragments of charred rhizomes of aroids were also found in sediments dated

to 23,850-23,020 cal BP, along with starch deriving from the Alocasia (Longiloba complex) or

Cyrtosperma merkusii that could also be associated with even older deposits. It is argued that

Niah Cave deposits represent a relatively broad spectrum subsistence base that included some

toxic plants such as taro which required higher energetic costs in food processing, but proving

that people were deliberately manipulating the distribution of favourable plants such as these is

another matter (2007:72). It is still therefore assumed that the archaeobotanical record of Niah

represents evidence for rainforest foraging of naturally distributed plant taxa. Looking beyond

these starch-rich taxa, a large number of other fruit and nut species including candlenut

(Aleurites sp.), coconut (Cocos nucifera), Pacific almond or galip nut (Canarium spp.), island

23

lychee (Pometia pinnata), Pandanus spp., and Pangium sp. have been identified from deposits

within the Sepik-Ramu region of New Guinea at around 5500BP (Swadling et al. 1991).

Lapita colonisers: Innovation and integration

Thus far, this review has been concerned with late-Pleistocene to mid-Holocene plant

exploitation in the Pacific, culminating in the earliest evidence for agricultural and

arboricultural systems which likely integrated endemic cultigens such as bananas, aroids and

yams. During the latter half of the Holocene, it is argued that a new intrusive culture,

linguistically and genetically distinct from the indigenous people of Near Oceania, arrived in the

West Pacific. These people belonged to the Austronesian-speaking Lapita culture, and were the

first to colonise Remote Oceania, bringing with them a number of cultigens that have been

labelled by some as the ‘transported landscape’ (Kirch 1984). Whether the origins of the Lapita

culture can be traced within Island Southeast Asia, or arose after occupation and interaction

within Papua New Guinea is still under debate. The archaeobotanical record indicates that,

within Near Oceania at least, the Lapita culture integrated some of these taxa that had already

been cultivated in New Guinea into broad spectrum subsistence systems (Gosden 1992; Kirch

1987, 1988, 1989; Matthews and Gosden 1997). These cultigens such as aroids and bananas

were then subsequently incorporated these into the suite of crops brought to Remote Oceania

after 3000 BP.

Within Papua New Guinea, a number of Lapita sites contain preserved micro- and

macrobotanical remains of indigenous and introduced taxa. Two sites are water-logged and

anaerobic conditions have preserved macrobotanical remains of fruits and nuts from a range of

tree crops. Remains from a mid- to late-Holocene site on Arawe Island are identified as deriving

from eight genera and six species including Aleurites sp., Cocos sp., Canarium sp., Cordia sp.,

Cycas circinalis, Dracontomelon sp., Pandanus spp., and Terminalia sp. (Mathews and Gosden

1997:124). Matthews and Gosden (1997) concede that the botanical remains could be the result

of natural beach drift, but point out that the best evidence for human involvement is

modification through extraction processes. Extraction can be seen from the fragmentation

patterns of the Canarium sp. and Terminalia sp., and charring of the Cycas remains (1997:128).

Clearly Canarium continued to play an important role as a food source throughout the

Holocene, as further evidence of the exploitation of this genera was found at another water-

logged site on Mussau Island (Kirch 1987, 1988, 1989). Over 5000 anaerobically preserved

seeds and seed cases representing at last 19 taxa, including Canarium sp., were recovered from

Mussau (Kirch 1988:337). These included coconut (Cocos nucifera), Tahitian chestnut

(Inocarpus fagifer), Corynocarpus caribbeanus, Dracontomelon dao, vi apple (Spondias

dulcis), Pometia pinnata, Pangium edule, and tropical almond (Terminalia catappa).

Additionally, a number of Pandanus spp. fruit segments were recovered from contemporaneous

deposits and shell peelers and scrapers that were argued to indicate the preparation of starchy

24

tubers and corms such as those of Dioscorea and Colocasia (Kirch 1987:177, Kirch 1988:338).

Kirch (1987, 1988, 1989) argued that this data represented the first direct evidence that Lapita

communities cultivated a wide variety of tree crops that are still used today in Melanesia,

indicating that Lapita culture possessed a full component of arboricultural species at 3200-2800

BP.

Gosden (1992:63) argues that the nature of almost identical plant remains from sites in

the Arawe and Mussau Islands indicate that these archaeobotanical records are not

representative of formative stages of agricultural development during the Lapita period, but

instead suggest well-developed arboricultural systems. Therefore, the transition to vegeculture

through integration of local and introduced root crop taxa within subsistence still needs to be

pinpointed. More recently, Lentfer and Green (2004) analysed the microbotanical record at the

Reber-Rakival Lapita site on Watom Island in PNG, with a focus on the phytolith assemblages

from three contexts. The presence of both introduced Eumusa and native Australimusa

morphotypes indicate that the Austronesians could have brought bananas with them, and

possibly at this same stage used the newly encountered cultivars in conjunction with their own

varieties, merging these two streams of banana domestication (Lentfer and Green 2004:85).

As Lapita populations expanded into Remote Oceania, further archaeobotanical

evidence indicates the continued integration of roots, tubers and tree crops into colonizing

subsistence regimes. In Vanuatu, microfossil evidence from the Lapita-associated sites of

Teouma, Vao and Urupiv point to the cultivation of aroids such as Cyrtosperma merkusii, a

range of yams including D. esculenta, D. nummularia and D. pentaphylla, and bananas by 3000

BP (Horrocks and Bedford 2004, 2010; Horrocks et al. 2009, 2014). It has been argued by

numerous researchers that the brackish conditions in beach back-swamps near many early

Lapita settlements would have enabled the initial cultivation of saline-resistant crops such as

Cyrtosperma prior to the establishment of more labour-intensive irrigation required for other

aroids such as Colocasia or Alocasia (Kirch and Lepofsky 1993; Kirch and Yen 1982; Yen

1973a, 1993). Contained within this argument is the assumption that Lapita populations did not

have intensive cultivation techniques, beyond an understanding that these aroids grow best in

wet conditions. The late materialization of irrigation within island sequences can be seen to

suggest that this technology was not transferred, but rather reinvented over generations or

millennia (Kirch and Yen 1982:267). Others such as Spriggs (1990, 2002) instead suggest that

the similarities between pond-field, island bed and taro pit wetland cultivation techniques across

the Pacific indicate that these were not independent innovations, and therefore derived from

prior knowledge and experience within founding populations. Moving east to Fiji,

microbotanical data derived from Bourewa on Viti Levu (Horrocks and Nunn 2007) contained

evidence for the starch, calcium oxylate crystals and xylem vessels of taro (Colocasia esculenta)

and the lesser yam (Dioscorea esculenta) at 3000-2500BP. These identifications would

25

therefore appear to support Spriggs’ (1990, 2002) argument but additional work is required to

further establish this link.

Micronesia: A different branch

Archaeobotanical research in Micronesia demonstrates the transfer and utilisation of crops east

of Island Southeast Asia within the late Holocene. On Kosrae, Athens and others (1996) have

collected both macrobotanical and microfossil data upon the antiquity of plant use within

archaeological and palaeoecological sequences. Wood charcoal of breadfruit (Artocarpus spp.),

Thespesia and Cordyline, along with the charred endocarp and seeds of coconut (Cocos

nucifera), Morinda citrifolia, Pandanus, Terminalia and Inocarpus, and storage parenchyma of

Alocasia taro and cf. Dioscoreaceae were recovered from excavations at Katem (1996:843). The

pollen record from Tafunsak contained abundant giant swamp taro (Cyrtosperma merkusii)

pollen coinciding with the earliest period of occupation at 1997-1709 BP, while breadfruit

pollen was only present in the latest interval at 1264-1150 BP (1996:843; Pickersgill 2004).

This information combined with the micro-charcoal record from the same core indicated that a

lowland agroforest was established on the island at a very early date, and further burning was

not needed as this would only damage existing crop trees (Athens et al. 1996:843).

Further south, Di Piazza (1998) identified evidence for introduced taxa on Kiribati

through analysis of wood charcoal and endocarp within an earth oven dated to around 1430 to

1645 AD. A number of species were interpreted as fuel sources including Cocos nucifera,

Cordia subcordata, Pemphis acidula, Guettarda speciosa, and Morinda citrifolia, as well as

edible remains such as Pandanus tectorius that had cooked in the oven. The pounding and

eating of the drupes of Pandanus have been recorded ethnographically (Di Piazza 1998), as well

as the utilization of the uneaten portions as the preferred fuel to ensure fires last long enough to

cook pigs or Cyrtosperma. Ethnographic and historic accounts highlight the importance of the

giant swamp taro within subsistence throughout Micronesia, as this saline-resistant crop can be

grown relatively easily within atoll environments. Although it has recently been discovered that

Cyrtosperma is actually endemic to Micronesia (Athens and Stevenson 2001), pollen of this

species has also been recorded at 4500 BP within the Ngerchau core in Palau (Athens and Ward

2001) but there is no supporting archaeological evidence for occupation.

Island Melanesia and Polynesia: Evidence for extensive and intensive cultivation

It is often assumed that early human arrival and colonisation in Remote Oceania introduced a

number of core cultigens within the taro-yam complex, and arboricultural taxa into a large

variety of island environments. As the socio-politics and material culture of these colonizing

populations evolved into what is sometimes termed Ancestral Polynesian Society (APS) within

Western Polynesia and then expanded east to the Society Islands, Tahiti, Marquesas, Easter

Island, Hawaii and New Zealand, plant cultivation also evolved to suit local growing conditions.

26

The difficulty of transporting crops by canoe over large stretches of ocean and plant

translocation led to the exclusion of some species from localised subsistence strategies. Post-

Lapita archaeobotanical evidence from islands within Remote Oceania has elucidated the timing

of these introductions, as well as the contexts within which these taxa were cultivated or

exploited.

This section of the review begins with an assemblage of microbotanical remains that are

not associated with Ancestral Polynesian Society, but instead with Podtanean post-Lapita

deposits in New Caledonia that are synchronous with this cultural transition in Polynesia.

Horrocks, Grant-Mackie and Matissoo-Smith (2008) identified cultigens including C. esculenta,

D. esculenta and one or more undifferentiated species of Dioscorea from identification of starch

granules and calcium oxylate crystals within archaeological deposits dated to 2700-1800 BP in

Me` Aure` Cave. The presence of these taxa was interpreted to fill a crucial gap in establishing

“a continuous spatio-temporal record of ceramic-age agriculture across the western Pacific

(2008:179). Further to this, Dotte-Sarout (2010; Dotte-Sarout et al. 2013) investigated whether

arboriculture could be identified from the anthracological record at precolonial Kanak sites in

New Caledonia, dated after 1300 AD. Results indicated a continuance of a forest gardening

tradition focusing on Ficus sp., Syzygium malaccense, Aleurites moluccana, Hibiscus tiliaceus,

Cordia subcordata, Calophyllum inophyllum, Artocarpus altilis, Cocos nucifera, Terminalia

catappa among others, originating from the Austronesian/Indo-Pacific sphere of interaction

(2013:133).

The Polynesian triangle is bound by the island groups of Hawaii in the north, New

Zealand in the south, and Rapanui to the east. This boundary defines the culturally and

genetically distinct Polynesians from the Melanesians of Fiji, Vanuatu, New Caledonia and

islands further west. The botanical record of Hawaii is important for investigating the expansion

of cultivars to the northern extreme of Polynesia. Along with Tonga, the Hawaiian archipelago

represents one of only a small number of cases where dryland agriculture was adopted (Yen

1982). It is often presumed that where possible, irrigation for taro will be developed and that

dryland techniques are a secondary choice (Spriggs 1982; Yen 1982). Both macro- and

microbotanical remains demonstrating the nature and extent of dryland crop utilisation have

been recovered from a temporally and geographically diverse range of archaeological sites.

Douglas Yen was the first to apply modern identification techniques to assemblages of plant

remains from dry rockshelters and open sites on Kaho’lawe Island, Molokai, Oahu and Hawaii

Island (Allen 1984). From these sites, a number of primary (Dioscorea alata, Ipomoea batatas,

Cocos nucifera, Musa sp., Lagenaria sp, Saccharum sp., Piper methysticum) and secondary

cultigens (Canarium sp., Pandanus sp., Cordyline sp., Aleurites moluccana) were identified

(1984:22-23). Following this, several projects targeted the recovery of carbonised and

desiccated plant remains using systematic flotation and sieving techniques. Rosendahl and Yen

27

(1971) recovered complete and fragmentary carbonised remains of sweet potato (Ipomoea

batatas) dated to between 1425 and 1725 AD, while Allen (1983, 1984) identified small

fragments of desiccated taro corm along with noni (Morinda citrifolia), coconut and kou

(Cordia cf. subcordata) that were interpreted as evidence for purposeful environmental

modification. Microfossil evidence from phytoliths and starch has thus far lent support to

identification of macrobotanical remains. Musa phytoliths were located within samples taken

from the Kona field system, along with the starch and xylem vessels of a root crop cautiously

identified as Ipomoea batatas, dated to 1300-1625 AD (Horrocks and Rechtman 2009). In an

attempt to combine both macro and microbotanical analyses, Kirch and others (2005) extracted

the charred remains of Cordyline fruticosa and many seeds from an earth oven from Kahikinui

dated to 460-280 cal BP, along with pollen, phytolith and micro-charcoal assemblages from

sediments that were interpreted as evidence for mulching practices consistent with those

techniques recorded ethnographically in Hawaii.

To the east, Rapanui, or Easter Island, has been the focus of archaeological projects

seeking to answer questions surrounding the enigma of the Moai statues and the prehistoric

Polynesian culture that created them. Despite this, very little archaeobotanical research has been

initiated. The question of agricultural development within subsistence practices has been raised,

and most often dealt with through consideration of the context of dryland agricultural features

(Stevenson et al. 1999; Wozniak 1999) and land evaluation (Louwagie and Langohr 2002;

Louwagie et al. 2006). The first to address agricultural change through the implementation of

archaeobotanical techniques was Cummings (1998) at La Perouse Bay. The contents of a

possible lowland garden-pit feature were analysed, and the microbotanical remains of both

sweet potato and taro were recovered in the form of pollen and starch granules, respectively.

Following this, Horrocks and Wozniak (2008) conducted a microfossil survey of sediments

within transects near ahu, house sites and presumed horticultural areas. These deposits were

found to contain pollen deriving from bottle gourd (Lagenaria siceraria), and starch of the

common yam (Dioscorea alata), sweet potato, and taro. The presence and abundance of these

taxa, along with pollen evidence of forest clearance, were interpreted as reflecting the intensive

mixed-crop, dryland production of these cultigens, dominated by yams and sweet potato, and

supplemented by taro and bottle gourd (2008:16). More recently, Horrocks and others (2012)

cored lake sediments in the crater of Rano Kau, and used a combination of light microscopy and

Fourier Transform Infrared Spectroscopy (FTIS) to assess microbotanical evidence for

agricultural practices within the crater. Some starch granules were much degraded, but were

able to be tentatively identified as that of sweet potato, the common yam and taro using FTIS

(Horrocks et al. 2012:195-198). In addition, pollen and phytoliths of other cultigens such as

paper mulberry (Broussonetia papyrifera), bananas, and possibly bottle gourd were also

28

identified and used to argue that the crater was the location for a mixed-crop horticultural

system after 1610-1410 cal BP.

Similar to Rapanui, New Zealand in the southern point of the Polynesian triangle is a

case study for archaeological projects investigating dryland subsistence in the lower latitudes,

specifically the subantarctic convergence zone of the Pacific. A large array of microbotanical

studies have been conducted on Maori gardening soils, gardening features such as stone walls

and mounds, house sites, coprolites, and within lake sediment cores from throughout the North

and South Islands (Horrocks 2004; Horrocks and Barber 2005; Horrocks and Lawlor 2006;

Horrocks, Smith, Nichol, Shane and Jackman 2008; Horrocks, Smith, Nichol and Wallace 2008;

Horrocks et al. 2002, 2003, 2004, 2007, 2011). Within these sediments a number of prehistoric

introductions are identified from diagnostic starch granules, phytoliths, pollen and xylem

vessels. The identified taxa include paper mulberry, sweet potato, Colocasia taro, bottle gourd,

and yams, indicating that multi-cropping of selections of these crops was common in production

systems that utilised lithic mulching and mounding to enable production of tropical cultigens in

a cooler temperate climate. Production was argued to have been supplemented by the

exploitation of native taxa such as bracken (Pteridium spp.). Almost all of this data has been

collected from deposits that have been radiocarbon or AMS dated to post- 1300 AD, or are

above the Kaharoa tephra (dated to 1300 AD). Currently there is no direct evidence for

agricultural practices from first settlement (around 1200-1300 AD) until this period.

On the outer edges of the Polynesian triangle, islands such as Futuna, Pitcairn and the

Marquesas Islands have also received attention from archaeobotanical research. Piazza and

Frimigacci (1991) analysed pollen records from three cores near water sources on Futuna dated

from around 600 BP to the present. Within these cores was direct evidence for the giant taro

(Alocasia), bananas (Musa spp.), and some species within the family Moraceae argued to most

likely be breadfruit (Artocarpus altilis) (Piazza and Frimigacci 1991:131). These crops were

interpreted as evidence for the antiquity of pond-field construction and swiddening practices,

which could be traced back to the Kele Mea period that pre-dated the development of socio-

political stratification, involving the the emergence of strong chiefly titles on the island. Turning

to the southeast, Hather and Weisler (2000) and Horrocks and Weisler (2006) have carried out

micro- and macrobotanical analyses of sites on Pitcairn Island in the Pitcairn Group. Leaf

parenchymatous tissues of Cyrtosperma merkusii were recovered in situ within archaeological

deposits associated with prehistoric earth ovens, dated from 1000-1600 AD (Hather and Weisler

2000) Following this, Horrock and Weisler (2006) analysed deposits within a stratigraphic

profile from a drainage ditch, and found evidence for the cultivation of sweet potato (Ipomoea

batatas) and taro (Colocasia esculenta) through the presence of starch and xylem vessels

consistent with these taxa. Unfortunately, there was limited age control in the disturbed profile,

and there is a possibility that these remains date to the historic period after the Bounty mutineers

29

settled the island. Work by Allen and Ussher (2013) on the island of Nuku Hiva in the

Marquesas has recently identified the presence of sweet potato on shell scrapers dated to 1200-

1400 AD. This represents the earliest direct evidence for the cultivation of sweet potato within

the archipelago. A number of other economic cultigens were also identified from residues on

multi-use shell tools from occupation sites in the Anaho Valley dated to after 1400 AD,

including kava (Piper methysticum), breadfruit, taro and a variety of yam (Allen and Ussher

2013:2810).

So far, this review has investigated archaeobotanical data for plant introductions and

cultivation in the outer limits of Polynesia. It will now turn to the interior of the triangle and

assess the research that has been carried out in the Cook Islands, Samoa and the Society Islands.

Chance finds of macrobotanical remains from Mangaia in the Cook Islands and Upolu in Samoa

have been identified by Hather (1994; Hather and Kirch 1991) using a systematic identification

system that has enabled the classification of parenchymatous fragments of roots and tubers. On

Mangaia, both charred epidermal tissues and unattached epidermal fragments identified as

peelings and the edible root sweet potato were collected from the Tangatatau rock-shelter in

conjunction with wood charcoal and the charred drupes of Pandanus tectorius (Hather and

Kirch 1991). The research was significant as it suggested that the sweet potato was in central

eastern Polynesia by 1000 AD, and was argued by the Hather and Kirch to lend credence to

Yen’s tripartite hypothesis for the distribution of this cultigen in the Pacific (1991:892-3). The

tripartite hypothesis proposes three pathways for sweet potato into Oceania: a prehistoric

transfer from South America to Polynesia, transport by the Spanish from Mexico to the

Philippines, and a later introduction from Europe to the East Indies and New Guinea

(Montenegro et al. 2008).

Further east, parenchymatous remains of Dioscorea spp. were identified using Scanning

Electron Microscopy (SEM) from excavations carried out by Green and Davidson (1969, 1974)

on the island of Upolu in Samoa (Hather 1992, 1994b). The fragments were 2-6mm in size and

were identified to genus from the morphology of vascular tissues, but the state of preservation

and lack of epidermal tissues inhibited classification to species. More recently, Kahn and

Ragone (2013) identified fragments of breadfruit (Artocarpus altilis) exocarp on house

platforms in the ‘Opunohu Valley on Moorea, Society Islands dated to around the middle of the

17th century. This built upon the chronology for the cultivation of breadfruit in Tahiti

established by Orliac (1997) when charred breadfruit wood was recovered an earth oven from

the Papeno’o Valley in rock-shelter deposits dated to the 14th century.

Tonga: The gap in the archaeobotanical record

Within Western Polynesia, the Tongan Archipelago represents an important location for

archaeological research. This island group is acknowledged both as the homeland for the

30

colonisation of East Polynesia, as well as the terminus for Lapita migration. Despite this, only a

very small number of palaeoecological studies have contributed information upon Polynesian

introductions and associated cultivation practices in Tonga. Fall (2005, 2010) and Fall and

Drezner (2011, 2013) document the first evidence of Colocasia in pollen cores taken from the

Avai’o’vuna Swamp and the Ngofe Marsh within the Vava’u group, and on Eua in the

Tongatapu group from 2600 BP. Other introductions at this time included Casuarina

equisetifolia, Cordyline fruticosa, and Pometia pinnata. Indigenous species such as Canarium

harveyi, Cocos nucifera and Pandanus tectorius display an increase in pollen associated with

Lapita settlement (2900-2600 BP) that may indicate their cultivation for food. In addition to

these Lapita-associated introductions, Fall (2010) documents the introduction of the Polynesian

cultigen Ipomoea batatas as a historic introduction into the archipelago. This supports Kirch’s

(1978, 1990) argument that the adoption of this versatile South American cultivar in Tonga

coincided with the arrival of Europeans. However, the cultivation of sweet potato was

documented in Tonga during Cook’s second voyage in 1777, which may in fact suggest

prehistoric rather than historic transfer of this cultigen. No macrobotanical remains have been

recovered from archaeological sites within the archipelago that could corroborate these

identifications, and there is a significant lack of horticultural features in the archaeological

record. The absence of an archaeobotanical record for Tonga is significant due to the

importance of these islands for Pacific migration, and therefore a targeted and systematic regime

of flotation, wet-sieving and bulk soil sampling for macro- and microbotanical remains the

logical approach to address this problem.

Tonga in the Pacific: A summary

Around the Pacific, archaeologists and palaeoecologists have begun to use multi-disciplinary

approaches that combine natural and cultural datasets to enable the development of chronologies

for localised and regional plant introductions and utilization. From the identification of taxa

within the archaeobotanical record, interpretations have been made about the movement of

crops around the Pacific region through island colonisation and trade, as well as the nature of

crop production through localised innovation and adaptation. It appears that the taro-yam

complex was the most extensive horticultural system and was transported from Near Oceania

into Remote Oceania by the Lapita cultural complex to all of the outer limits of East Polynesia.

Current archaeobotanical data reflect the movement of human and plant populations

throughout the Pacific, but also local environmental limitations and cultural practices that

affected the number and types of cultigens that were grown. Further east, islands become higher

and entirely volcanic in origin, making irrigation ineffective in more temperate climates. It is

reasonable to assume that these island populations relied less on those aroids that required some

form of irrigation, such as Alocasia and Cyrtosperma to ‘intensively’ cultivate, and instead

‘extensively’ cultivated dryland crops through mounding such as yams (Dioscorea sp.) and

31

sweet potato (Ipomoea batatas) or the arboricultural production of breadfruit (Artocarpus sp.)

and bananas (Musa sp.). However, questions have been raised regarding how to define intensive

agriculture, and how visible these cultivation techniques are within the archaeological record

(Leach 1999).

The assumption that population growth and social production are the primary drivers for

intensification, begs the question as to how to explain cases such as the Tu’i Tonga chiefdom

under current typologies where intensification in the traditional sense (Boserup 1965) is defined

as increased labour input holding land as a constant. By European arrival, almost all of

Tongatapu was dedicated to agriculture, but to fit this classic definition for intensification this

dryland production would be required to have developed from swidden agriculture with a

shortening of fallow length in plots, followed by permanent plot boundaries and a trend towards

rain water control and soil additives (Yen 1973a). A chronology of horticultural production is

required to identify this process, something currently lacking within archaeological research in

Tonga. In light of this, this thesis investigates the development of production systems over time

using Tongatapu as a case study, and seeks to elaborate upon and test modes of production other

than the classically defined intensive techniques, using archaeobotanical data and

agroecological modelling.

32

PART ONE- AN ARCHAEOBOTANICAL

COMPARATIVE COLLECTION FOR

TONGA

33

Chapter 3 Reviewing Microbotanical

Analysis

This study uses a combination of both micro- and macrobotanical techniques to research

subsistence strategies adopted within the Tongan archipelago in prehistory. Starch analysis and

the study of charred parenchyma are both areas of archaeobotany that have been under-utilised

due to perceived issues with taphonomy, extraction and the diagnostic value of morphological

characteristics of these botanical remains. This chapter explores past research, and demonstrates

that the cumulative data from experimental studies, ethnography and applications of these

findings within archaeological research has enabled a greater understanding of human-plant

interaction. The current study will utilise the results of past research into taphonomy and

identification techniques, and develop these further to enable later classification of these micro-

and macrobotanical remains extracted from sites on Tongatapu within Part Two of this thesis.

Although it is a relatively new area of archaeobotany, starch analysis has been applied

to answer a range of archaeological questions regarding population migration, diet and

subsistence, tool function, and human-environmental interaction. Yet the chemical and

biological properties of starch as a carbohydrate, and how these can change under different

conditions such as heating or cooling, are still mostly not well understood. Reichert (1913)

conducted the first scientific study of starch and its properties, and his seminal guide is often

used in microbotanical research. Variation in starch morphology at different taxonomic levels is

well known, and has been used to identify starch found in sediments (Horrocks et al. 2004,

2008; Horrocks and Lawlor 2006; Horrocks and Rechtman 2009; Lentfer et al. 2002; Therin

1994; Therin et al. 1999) or as residues on stone artefacts (Barton 2007; Field et al. 2009;

Fullagar 1998, 2006; Fullagar et al. 1998, 2006; Loy et al. 1992; Loy 1994; Pearsall et al. 2004),

pottery (Crowther 2001, 2005, 2009), and dental calculus (Boyadjian et al. 2007; Henry and

Piperno 2008; Reinhard et al. 2001).

Biology of starch and identification potential

The biological characteristics of starch grains offer a unique picture of plant use in the past.

Starch is produced as a form of energy storage during photosynthesis and is found in plastids in

every kind of tissue in most green plants. Light energy is converted to potential energy within

the chloroplasts found in leaves through the splitting of water into hydrogen and oxygen (Banks

and Greenwood 1975; Gott et al. 2006). The freed hydrogen combines with carbon dioxide from

the atmosphere to form glucose, which is stored in two forms. It can be hydrolysed, synthesised

and then stored overnight as reserve starch within the amyloplasts in storage organs such as

roots, tubers, fruits and seeds (Cortella and Pochettino 1994:172; Jane et al. 1994), or used

during the day as transitory starch in chloroplasts (Banks and Greenwood 1975:1). Transitory

34

starch is much smaller and less diagnostic than reserve starch and is mostly found in the leaves,

stem and petiole (or leaf stem) (Banks and Greenwood 1975:1; Gott et al. 2006; Messner 2011).

Starch itself is biologically defined as discrete insoluble semi-crystalline polymers

consisting of linear amylase and highly branched amylopectin. The internal structure of these

granules is composed of alternating semi-crystalline and amorphous growth rings, and an

amorphous core (Cai and Wei 2013). Granules are formed within the plastids from a nucleation

point, or hilum, from which these layers of amylose and amylopectin are accreted (Loy

1994:89). The optical pattern created by these layers is called ‘lamellae’, and these increase in

density and insolubility towards the outer margins of the granule. Three different types of

crystalline structures have been identified within starch granules through X-ray diffraction

techniques, designated as A-, B- and C-types (Banks and Greenwood 1975:242; Gott et al.

2006). A-types contain a pattern that is visible in most cereals, while B-types are seen

commonly in tubers and C-types are within most root and seed starches (Cortella and Pochettino

1992:178). Heat and moisture during plant growth dictate the percentages of each type produced

within the plastids.

Partly due to the semi-crystalline structure of starch, granules are also birefringent in

polarised light, displaying a ‘Maltese’ or ‘extinction cross’ pattern. This effect is created by

light passing through the grain which is deflected owing to the differences in density and

structure of the various lamellae. This deflection creates interference which in turn results in the

generation of localised bright and dark regions that extend radially when polarised due to the

spherical shape of granules (Loy 1994:89). These interference patterns are not unique in their

physicochemical structure and can sometimes be confused with synthetic semi-crystalline

polymers which form spherulitic structures that are not unlike starch in the early stages of

growth when viewed in polarised light (Banks and Greenwood 1975:247). However, it is the

combination of attributes that are visible in both polarised and brightfield light that permit the

direct identification of starch grains microscopically.

The growth of starch within the plastids is under genetic control, and size and shape of

granules is determined by the conditions within the cell. The type of starch granule that grows is

also dictated by the plastid, where a single nucleus gives rise to a ‘simple’ starch granule and a

multiplicity of nuclei form ‘compound’ granules (Banks and Greenwood 1975:251; Gott et al.

2006:41; Loy 1994:90). Each granule within a compound granule exhibits its own birefringence

pattern and has the potential to separate and become simple granules. Other traits such as the

morphology of the hilum region including vacuoles and fissuring, and the density,

hydrophobicity (insolubility) and thickness of the accretion layers are also inherited genetic

effects (Loy 1994:91). Because of genetic control over starch morphology, there is the potential

to identify the botanical origin of native starch. Some granules within a population are highly

35

diagnostic, whereas others are less useful for identifying the species of origin due to features

that overlap with other taxa (Gott et al. 2006:40). It is these diagnostic or ‘signature’ types that

are mainly used to identify unknown taxa found in archaeological assemblages.

Many studies of species-specific starch morphology and physicochemistry have been

conducted to assess the range of variation within any given sample at different taxonomic

levels. Initial studies only used light microscopy (Gott et al. 2006; Barton and Fullagar 2006;

Reichert 1913) but more recent use of Scanning Electron Microscopy (SEM) enables high

resolution imaging of the three-dimensional shape of starch (Barton and Fullagar 2006:52; Jane

et al. 1994; Lindeboom et al. 2004). Comprehensive analyses of starch morphology have

demonstrated that attributes such as the presence of lamellae, hilum features, three- and two-

dimensional shape, shape modifiers such as faceting, and overall size, characterise different

biological taxa. Further, there is also evidence that starch can vary morphologically within

different organs of the same plant (Gott et al.2006; Jane et al. 1994:46; Loy 1994; Reichert

1913), which suggests that if these features were also diagnostic, it could be particularly useful

to archaeologists attempting to understand plant exploitation and processing in the past.

Starch taphonomy

Detailed studies in both archaeobotany and the food sciences have emphasised the range of

changes that can occur when native starch is exposed to a range of physical, chemical and

biological environments. A number of methodological studies have focused on these

taphonomic issues, highlighting the changes that can affect native starch biochemistry and

morphology under differing conditions both prior to and after deposition, and how these factors

can influence the identification and quantification process (Babot 2003; Crowther 2009, 2012;

Haslam 2004; Henry et al. 2009; Weston 2009).

Plant processing

Archaeobotanical research targets plant remains that are found within archaeological, and

therefore anthropogenic, contexts. Most starch remains found within domestic deposits such as

occupation floors or middens derive from economic or supplementary plant taxa that have been

processed in some way. Roasting, charring, boiling, milling, pounding, freezing, dehydrating,

and rehydrating are all examples of cultural food processing techniques that can affect the

morphology and chemistry of starch granules (Babot 2003; Crowther 2009; Henry et al. 2009;

Laurence 2013:34-36; Messner and Schindler 2010). The effects of various cooking techniques

on starch have been by far the most researched of these processing techniques. Experiments

have been tailored to assess the range of the conditions under which starch either melts or

gelatinises when exposed to water and/or heat.

The thermal conversion of starch is defined when “…starch is converted from an

ordered, semi-crystalline to a disordered, amorphous state during cooking…” (Crowther 2012,

36

2009:23). Gelatinisation can occur when starch is exposed to both moisture and increased

temperature, causing swelling and a loss of birefringence (Banks and Greenwood 1975:259-67;

Messner and Schindler 2010). Species-specific water-dependent temperature thresholds affect

the nature and timing of starch thermal conversion (Crowther 2009; Henry et al. 2009:917), but

complete and uninhibited gelatinisation of all granules can only occur when more than 60-65%

water is present. Within most Pacific cultigens the temperature range for gelatinisation under

excess moisture is around 60-85˚C (Moorthy 2002). Partial gelatinisation is possible when these

conditions are not met and the amylopectin crystallites only partly melt, resulting in an

incomplete loss of birefringence and limited morphological change. Swelling is also reversible

up to a point when loss of optical properties begins, which occurs within a population of starch

grains over a relatively narrow temperature range of 5-10˚C (Banks and Greenwood 1975:260).

Melting of starch crystallites occurs when granules are dry-heated, through charring or

roasting at temperatures above 220˚C. Starch heated in the absence of moisture will thermally

degrade through breaking down into smaller glucose units and eventually carbonise before

becoming structurally disordered (Crowther 2012, 2009:26). Experimentation has demonstrated

the visible changes that can occur during these types of cooking techniques. Babot (2003)

roasted samples of corn (Zea mays L.) kernels and quinoa (Chenopodium quinoa Willd.),

reporting that these granules displayed various combinations of flat relief, weak birefringence,

deformation of the extinction cross, clumping and slight gelatinisation, but not all grains showed

gelatinisation features. Babot concluded that the water content at time of cooking and the

heating temperature were responsible for the damage (Babot 2003:73). Similarly, the effects of

charring were evident in changes in granule birefringence, swelling and clumping, but were

dependent on grain size (Babot 2003:74). Starch size is related to hydration, where water

molecules inhabit the crystalline regions of the amyolopectin molecules (Torrence and Barton

2006). Smaller starch granules have less capacity for swelling, while gelatinisation occurs more

quickly for larger granules unless these granules have a high ratio of amylase to amylopectin

which buffers gelatinisation (Banks and Greenwood 1975:260; Crowther 2012; Saul et al.

2012:3484).

Studies also demonstrated that gelatinization is not as simple as dry heat versus wet heat

cooking, or charring and roasting versus boiling. Consideration must be given to the role that

heat-transfer mechanisms and micro-climates have in the cooking process (Messner and

Schindler 2010). In earth ovens the thermal agent is heated rock. When these are placed in direct

contact with starchy organs, the oven is instantaneously heated through trapping hot moist air

which emanates from the food and is then vaporised when this comes in contact with the rocks,

resulting in complete breakdown of starch within the oven (2010:334). In contrast, when the

external heat source is in the form of fire on top of the earth oven that increases in temperature

gradually, the moisture is slowly evaporated from the organ and starch is damaged but can still

37

survive cooking. Messner and Schindler (2010) therefore argue that “…the environmental

conditions generated by the heat transfer systems were of greater influence to starch degradation

than temperature alone.” Different water-uptake mechanisms in different wet cooking methods

also affect the rate and nature of gelatinization. For example, boiling increases water absorption

at a faster rate, but steaming allows more uniform absorption over time (Crowther 2009:28-29).

These factors, and the type and order of cooking procedures followed can greatly affect the

archaeological visibility of particular activities. Two of the main methods for cooking starchy

foods in the Pacific throughout prehistory have been by steaming in earth ovens and boiling, so

these studies’ findings are particularly relevant to this study.

Other studies have demonstrated that the temperature during charring can significantly

alter the nature of starch damage. Low temperatures up to 220ºC will not commonly cause any

morphological changes, but higher temperatures up to 350ºC can cause complete loss of

structure or fusion of granules similar to those observed within boiled samples at lower

temperatures (Valamoti 2008). Similarly the location of starch within an organ that has been

cooked whole at any temperature will limit the amount of damage. For example, granules in the

centre of grains are more likely to survive any cooking method as these are protected from the

effects of liquid and heat (2008:269). Some alteration of morphology, such as slight swelling, is

still possible.

Crowther (2012, 2009) reviews the potential for starch survival within charred and

carbonised residues on ceramics, and argues that these are ideal contexts for recovering non-

gelatinised granules as evidence of cooked foods under particular charring conditions. The

temperature must not exceed starch thermal degradation temperature, but this depends on the

intensity of the heat source, the distance of the vessel from that source and the location on the

vessel where the granules are located. Secondly, desiccation and carbonisation must occur

relatively quickly before all starch granules undergo gelatinisation. Starch granules of

underground storage organs (USO) such as roots and tubers are less likely to survive charring

without gelatinisation due to the high water content within these organs, biasing the

archaeological record towards cereals and legumes where these organs are utilised (2012).

Further studies have looked beyond the morphological changes that can occur within

starch granules exposed to charring, and instead attempted to assess whether the survival of

starch granules within charred residues reflect the intensity of plant use. Raviele (2011)

replicated charred maize residue construction under controlled conditions, where the variables

tested were the ratio of plant extract to water and meat, and the type of maize (Zea mays) (whole

green cob, whole green kernel, lightly pounded dried kernel, whole dried kernel and ground

maize flour).The overall results did not demonstrate a trend for increasing abundance with

increasing proportions of maize in residues, suggesting differential survival of starch during

38

charring. Despite this, it was noted that dried kernels and cob had higher abundances of starch

survival, most likely a result of high starch production within maize at this time of organ

development (Raviele 2011:2711). Similarly, Saul and colleagues (2012) experimentally

replicated charring conditions for einkorn (T. monococcum) and acorn (Quercus sp.) in ceramic

pots at more than 100ºC for three hours. These experiments indicated that starch can survive

repeated charring episodes in relatively high quantities (184 granules mg-1 and 608 mg-1

respectively).

Other food processing techniques such as parching, fermentation, freezing and milling

can also cause distinctive damage to native starch granules. Henry and others (2009) tested

different cooking techniques on both ground and whole legumes and grains. One of these tests

involved parching three millilitres of each sample for three minutes in a muffle furnace at

200ºC. The authors noted a significant degree of heterogeneity within the sample, but argued

that parching caused the most distinctive damage to granules (Henry et al. 2009:918). Most

granules appeared encrusted with small particles that were either small starch granules or other

organic material, which does not occur through any other cooking technique. Other common

morphological changes associated with parching were the definition of lamellae and

development of deep radial fissures (Henry et al. 2009:921). Within the same study, starch

granules were exposed to yeast to replicate fermentation. Whole samples displayed surprisingly

little change except for a possible extra ‘arm’ within the extinction cross; however, granules

within the ground samples often displayed signs of ‘hollowing out’ at the hilum. (2009:921).

Effects of freezing on starch granules from several cereals, tubers and legumes has also

been tested, and indicate that this process changes both the chemical properties of the starch

granules, specifically a loss of birefringence, and also the physical appearance of the grains in

terms of flat relief, fragmenting, fissuring, breaking and bursting (Babot in Beck and Torrence

2006:66-67; Babot 2003:74). Milling involves the application of friction to plant parts and their

by-products, and is a technique most commonly used for separating the starchy endosperm of

grains from the pericarp (Henry et al. 2009:916). Experimentation has revealed the extensive

damage that milling can have on starch granules, which includes truncation, incompleteness,

fracturing, collapsing, and bursting (Babot 2003:76). Some damage also can occur at the hila,

with fissuring and large open vacuoles. In contrast, short term pounding using stone implements

has been demonstrated to have very limited affect on starch granules aside from the

disaggregation of compound granules (Robertson, in Beck and Torrence 2006:68-69).

Damage caused by these various food processing techniques can render starch

unrecognisable as such in archaeological contexts. Studies have therefore attempted to use other

chemical tests to identify the presence of cooked starch residues on artefacts or in sediments.

Congo Red (empirical formula C32H22N6O6S2Na2) stain has been used in the agricultural and

39

food sciences as a contrast stain for cellulose, starch and amyloid fibrils, but the potential of this

stain to test for cooked or damaged starch in archaeological contexts has only been recognised

within the last two decades (Cortella and Pochettino 1994; Lamb and Loy 2005; Lamb 2003;

Reichert 1913; Weston 2009). The stain only binds to proteins in alkaline or acid buffer

conditions, so at a neutral pH only starch and cellulose will be stained. Unaltered or undamaged

starch is hydrophobic and so does not take up the stain, but starch that has become disordered

allows Congo Red to react with the amylase content of these granules resulting in a red

discolouration with an orange-red or green-gold glow in cross-polarised light (Lamb and Loy

2005:1434). Trypan blue has been used in much the same way, penetrating the outer layer of

damaged starch granules to stain the exposed interior blue (Barton 2007:1734).

Some researchers have argued that these stains are not reliable indicators of the

presence of starch within archaeological contexts, and have subsequently experimented with

thermally stable α-amylase, an enzyme that degrades the chemical linkages contained within

starch (Hardy et al. 2009). These tests involve exposing a sample of extracted residue to α-

amylase and observing the degradation of objects tentatively identified as starch (2009:251).

Alternatively a sub-sample can be used as a control by adding α-amylase, and comparing this to

the remaining analysed portion of extracted residue (Saul et al. 2012). If starch is thought to be

present in the remaining sample but not visible within the control, then this is a good indication

that the identification of starch within an archaeological sample is correct. However, this can be

problematic as it is not possible to confirm the identification of individual granules.

Starch in sediments

Soil properties such as pH levels, temperature, texture and moisture content, in conjunction with

soil constituents including enzymes, bacteria, fungi and earthworms, play the greatest role in

influencing starch degradation and movement after deposition (Barton and Matthews 2006;

Haslam 2004:1721). These factors are particularly relevant in tropical climates such as Tonga

which generally have low rates of organic preservation (Hather 1994). A large array of studies

has been carried out under varying soil conditions, either as individual variables or in

conjunction with one another. These experimental studies been utilised by archaeologists and

archaeobotanists to further our understanding of the extent to which morphological and

chemical changes can occur after deposition within archaeological contexts.

One of the most common causes of starch degradation within tropical sediments is

through hydrolysis, whereby starch is chemically broken down by polysaccharidases (enzymes)

produced by bacteria and fungi. When plant and animal cellular material decays, these enzymes

are released into the soil in significant quantities and are present in almost every soil type

encountered throughout the world (Cheshire et al. 1974). Two classes of enzyme-producing

bacteria are recognised: autochthonous, which grow slowly and predominate when there is little

40

oxidisable substrate and zymogenous, which respond to substrate addition by rapidly increasing,

with the majority dying out after substrate exhaustion (Burns 1982; Haslam 2004). It is

therefore possible for inactive enzymes and the bacteria that produce them to exist in the soil

prior to starch deposition. The presence of these enzymes, and their potential to remain inactive

in the soil substrate, limits the potential for starch survival in archaeological contexts.

To gauge the extent and rate of starch degradation, several studies have replicated

hydrolysis in vitro (Mellon et al. 2002; Steup et al. 1983). Results indicate that the majority of

both transitory and reserve starch is degraded within the first few days of exposure to enzymatic

digestion, with rates of decomposition after this following an asymptotic curve (Haslam

2004:1720, Barton 2009). Within this generalised trend there are species-specific differences in

enzyme attack patterns and rates, depending upon factors such as granule structure and size,

amylose to amylopectin ratios and crystal types (Haslam 2004: 1720; MacGregor 1980; Zhang

et al. 2005). Haslam (2004) compiled these studies into a table that archaeobotanists can use to

understand and interpret possible biases in the archaeological record. When ranked, taxonomic

patterning suggests that the rate of enzymatic degradation increased when granule size and

amylose content decreased. Some species such as bananas (Musa and Eumusa spp.) are resistant

to enzymatic degradation unless gelatinised (Zhang et al. 2005:144). Once gelatinisation begins

the rate of degradation increases as enzymes have easier access to the more susceptible

amorphous cores of the granules of most taxa. The temperature at which gelatinisation occurs

does not appear to be a significant factor affecting the rate of starch degradation for each taxa.

However, as discussed previously, the amount of moisture in the soil regulates the extent of

swelling and gelatinisation and thus has more impact (Haslam 2004). One variable that does

seem to affect the presence of microbial, enzyme and fungal activity in soils is depth. Enzymatic

degradation of starch is much more likely to occur closer to the surface than at midpoints or

near basal deposits, where activity is correlated with the presence of other organic matter

(Haslam 2004:1721; Taylor and Belton. 2002). The rate of starch degradation is also seen on

artefacts, where starch abundance at 108 weeks is already representative of those in

archaeological contexts (Barton 2009:135).

Other taphonomic factors that affect starch preservation in sediments include

temperature, pH and moisture content of the sedimentary matrix. These variables have the

potential to damage starch through causing gelatinisation or damaging the biochemical

properties of granules; however, these rarely directly affect starch individually, and so should be

considered in conjunction with enzymatic hydrolysis (Haslam 2004). It is the interplay between

these variables and the presence of microbial and enzyme activity that cause starch degradation.

As mentioned earlier, temperature and moisture cause swelling and shrinking of starch, enabling

various enzymes access to the interior of the granule. The same principles described in relation

to heating and cooling within food processing techniques is applicable to soil conditions.

41

Hydrolysis can also occur in both acidic and alkaline soils, but is slower than enzymatic

decomposition (2004:1721). Some enzymes often favour different pH levels, such as invertase

which is more active in more alkaline soils, whereas amylase can affect starch in any conditions

(Dick et al. 2000).

Quantitative studies of starch preservation (Barton 2009; Haslam 2009; Therin 1998)

have made observations of displacement of starch within sediments over time. Therin (1998)

attempted to replicate the downward displacement of starch grains in various sandy matrices

using groundwater. Variables tested included sediment particle size, irrigation rate and starch

grain size, monitored over a two-month period. The results indicated that there is limited

downward movement of starch grains, but within this overall trend patterning related to granule

and particle size. Larger starch grains have less chance of becoming mobile, but if they do

move, these granules move slowly and have less chance of becoming trapped. Smaller sand

particles also correlate with less starch mobility, but an increase in irrigation rate will increase

starch movement. Haslam (2009) attempted to take this experimentation a step further, and

investigate both upward and downward movement of starch, as well as lateral movement. These

parameters mirrored those used by Therin (1998), but only one sand matrix was tested with

larger particles of 250-500µm. The sediment was autoclaved for 30 mins at 120ºC to eliminate

fungi and bacteria then placed into a PVC pipe ‘cross’ with a small amount of starch (0.1g) in

the centre, and placed upright (Haslam 2009:95). The experiment was irrigated at a rate of

160ml twice a day from the top of the set-up for a period of 30 days. The sediment was then

sampled at 27 locations within the cross and processed for starch extraction, revealing that

around 16% of starch moved downward up to 6cm although the highest number of starch was

still found at the centre (2009:98). Very small numbers of starch also moved laterally up to

12cm, and upwards 2cm from the centre. The implications of these experiments are that

researchers need to assess factors such as sediment compaction, particle size and local rainfall

when interpreting the potential movement of starch in sediments, along with other taphonomic

issues such as bioturbation and human activities.

Researchers have sought to provide solutions to taphonomic issues through

investigating the types of conditions that are favourable for starch preservation (Barton 2009;

Haslam 2009, 2004; Laurence 2013). The presence of heavy metals within soils or high clay

content can neutralise enzymes and thus limit the effect that bacteria and fungi can have on

starch granules within these deposits (Haslam 2004). Additionally, soil aggregates, or

Particulate Organic Matters (POMs), and residues on artefacts can form a protective barrier for

starch through limiting surface area accessible for enzyme digestion. Artefact surfaces can also

provide a micro-environment that protects starch from the effects of temperature, moisture and

downward displacement through groundwater. Studies of starch residues on bone, wood, lithic

and ceramic artefacts indicate that the preservation of these residues in soils is possible.

42

However, experiments that attempt to replicate archaeological deposition of tools used for food

processing have produced no conclusive results (Barton 2009; Haslam 2004; Lu 2003). The

results of one study indicate that starch is in fact more likely to survive as residues on artefacts

if the tool remains on the surface for some time, as sunlight can reduce enzymatic degradation

(Barton 2009). Another experiment found that starch residues on buried tools had high survival

rates of around 75% after 71 days (Lu 2003:124), but the highest quantities of starch were found

on tools that were in sheltered conditions on the surface which supports Barton’s (2009)

hypothesis.

Modern starch contamination

Contamination has plagued archaeobotanical studies involving the analysis of microbotanical

remains. Many studies have attempted to understand the nature and sources of contamination

that can occur both in situ and during post-excavation processing in the laboratory.

Contamination is defined here as starch that can be added to samples through aeolian (airborne)

processes or through transmission by direct contact. Laurence (2013; Laurence et al. 2011)

provides an extensive review of modern airborne starch contamination that derives from food

processing factories such as flour and maize mills, as well as starch that is contained in pollen.

Pollen starch is undistinguishable from reserve starch and can be released when pollen ruptures

either on the ground or mid-air (Laurence et al. 2011:215). Both insect and wind-pollinated

species can produce pollen starch which provides energy for the pollen tube (Baker and Baker

1979). Microscopic slides placed close to sites in Texas where earth ovens were being assessed

for ancient starch contained quantities of starch after 96 hours.

Other researchers have recommended that archaeological studies should incorporate an

assessment of environmental airborne starch contamination in the field (Loy and Barton 2006;

Messner 2011). Yet others recommend sampling sediments surrounding artefacts to assess

whether residues on tools are accurate representations of use or contamination (Barton 2007,

Loy et al. 1992; Williamson 2006). This is determined through the taxa and quantities present in

either sample. This is problematic for a number of reasons. Fullagar and others (1998:51) argue

that the: “...difficulty in comparing starch grains on tools with starch grains in sediments is the

arbitrary choice of a quantity of sediment for a comparison with a given quantity of residue”.

Similarly, as pointed out earlier, starches in sediments can be more prone to enzymatic

degradation, so false negative results can be the outcome of these studies (Laurence et al. 2011;

Zarillo and Kooyman 2006). It is also difficult to argue that starch found in sediments is

contamination or vice versa, if consideration is given to the fact that an area may have been used

for food processing and that a tool was left in the same location after use.

Transmission of starch through handling and equipment is another source of

contamination in the field. This has been addressed in a number of studies, particularly those

43

concerned with residues on artefacts. Handling of an artefact both during original use and post-

excavation processes can cause starch to become attached to both working surfaces and other

areas of the tool that are not directly related to use (Barton 2007; Loy et al. 1992). Modern

handling contamination can be avoided by wearing starch-free gloves when bagging artefacts

into new zip lock bags in the field (Barton et al. 1998:1233; Hart 2011), but often analyses

include artefacts that have been excavated without these protocols and so researchers have

sought a means to test for levels of contamination. Suggestions to control for contamination

include testing various locations on the artefact, proposing that use-related starch is

concentrated around working edges (Barton et al. 1998; Loy et al. 1992; Piperno and Holst

1998). Another control is to compare artefact use-wear with the results of starch analysis (Allen

and Ussher 2013; Barton 2007; Ussher 2009). Where these are complementary, this provides

strong support for food processing technology.

Airborne native starch can not only contaminate sediments in situ or during fieldwork,

but also within the laboratory along with starch found in chemicals or through manual

transmission. There have been a number of published studies highlighting potential sources of

starch contamination in laboratory environments (Crowther et al. 2014; Laurence 2013;

Laurence et al. 2011; Loy and Barton 2006; Loy et al. 1992; Messner 2011). The most extensive

of these is that carried out by Crowther and others (2014), where not only the consumables and

equipment in the laboratory were tested for the presence of starch, but also surfaces and air

within various working spaces. This was designed as a comparative study between ancient

starch laboratories at the University of Calgary and Oxford University, and the results strongly

suggest that starch contamination is a major concern that needs to be addressed before

interpreting archaeological material. Consumables were tested by sampling liquids or exterior

swabs, while environmental samples were taken using horizontal ‘passive’ traps, or vertical

stationary or mobile adhesive traps. High numbers of wheat (Triticum sp.), maize (Zea mays)

and potato (Solanum tuberosum) starch were found on particular brands of powder-free gloves,

pipette tips, paper towels, and within Calgon and Sodium polytungstate commonly used for

heavy liquid separation (Crowther et al. 2014:86). Spaces that had significant quantities of

starch included fume hoods, floors and work benches, but these numbers were lessened after

cleaning.

Crowther and others’ (2014) study corroborate data from previous studies. Powder-free

gloves have been also been tested for starch contamination by Laurence (2013; Laurence et al.

2011) and others within the medical sciences (Campbell et al. 1984; Makela et al. 1997;

Newsom and Shaw 1997; Wilson and Garach 1981), and found to have varying quantities of

maize starch. These gloves are manufactured in the same factories as powdered gloves, and

therefore can easily be subjected to contamination by airborne starch if care is not taken.

Similarly, Newsom and Shaw (1997) conducted a survey of airborne starch within a hospital

44

environment and found that an average of 13.8 granules/30L air was present even in areas such

as intensive care units. Many of the starch granules observed within these studies displayed

signs of morphological and physicochemical modification such as cracking and gelatinisation

(Crowther et al. 2014:101; Laurence et al. 2011:228), indicating that the condition of starch

cannot necessarily be taken as an indicator of its age.

Protocols that limit the potential for modern starch contamination in the field and in the

laboratory have been developed in response to these studies. There are no alternatives for

powder-free gloves, but some brands have little or no starch contamination and should be

selected over others (Crowther et al. 2014). It is also possible to limit the amount of contact

gloves have with samples by using equipment such as sterilised forceps. Limiting or excluding

the use of paper products can also reduce the amount of airborne starch within the laboratory

environment. All centrifuge tubes, mixing rods, Petri dishes, sieves and pipette tips should be

treated for decontamination with 5% sodium hydroxide (Crowther et al. 2014:102) or

hypochlorite (Laurence 2013: 52; Laurence et al. 2011) prior to use. These protocols are also

replicable in the field, where particular powder-free gloves should be worn when handling

samples, and contact with the sample should be limited before placing in zip lock bags. All

sampling equipment at the very least should be cleaned with boiling water before use, but

disposable items should be utilised where possible. Food should also not be consumed on site

(Loy and Barton 2006:165).

Spatial differentiation for various tasks within the laboratory is also essential. Any

processing of modern starches for reference collections or experimentation should be carried out

in a different room to that where post-excavation processing of sediments is usually undertaken

(Crowther et al. 2014; Loy et al. 1992). This is especially important if samples are being

dehydrated and then milled or pounded. Consumable and environmental contamination should

be monitored on a regular basis to ensure the risk of contamination is low during different stages

within the working week or seasons. Monitoring of airborne starch in the field is also a useful

measure to at least provide a gauge of the most common modern morphotypes and quantities of

starch within the local environment (Crowther et al. 2014; Laurence et al. 2011; Loy and Barton

2006).

Sampling strategies and extraction techniques

Research on sampling and extraction techniques has continually forced revision of the methods

used to extract starch. These differ technically when researchers are dealing with residues on

artefacts or in sediments, but issues of scale influence both. By nature micro-analyses such as

microbotanical studies represent high resolution palimpsests of events occurring in the past, but

it can be difficult to interpret the spatial and temporal scale of these events. It is therefore

essential that the choice of a sampling strategy is related to a specific research question, and the

45

connection between the microbotanical remains and the processes that created the

archaeological record is made explicit by comparing samples. It is this comparison that ensures

that a sample represents more than just micro-scale data. Here, discussion focuses on the

sampling and extraction of sediments, as this relates to the methodological approach employed

on Tongatapu in the current research.

Many microbotanical studies target multiple microfossils, and an appropriate sampling

strategy incorporates taking samples from a combination of archaeological features and

background environmental deposits in swamps or trenches. Samples need to be of an

appropriate size, or multiple samples should be taken from the same contexts, due to problems

stemming from the use of combined multiple microfossil extraction techniques (Coil et al. 2003;

Korstanje 2003; Torrence 2006b). Pearsall (2000) provides a number of different guidelines for

sampling strategies that target either individual excavated contexts such as house floors, or sub-

sampling multiple contexts from stratigraphic profiles. Often project research questions dictate

the selection of one of these over the other, but an excellent example of integrating both these

techniques was published by Coil (2003) in a study targeting changes in agricultural practices

and ecology as part of the Kahikinui Archaeological Project in Hawaii. The combination of

archaeological and palaeoecological data from individual features, trenches in agricultural

landscapes, and sediment cores enabled discussion of landscape use and change within temporal

and geographic scales.

Where studies focus on site function, sampling tends to target individual features or

contexts of interest within a defined boundary. In the Pacific, Horrocks (and Barber 2005;

Horrocks and Bedford 2005, 2010; Horrocks, Smith, Nichol, Shane and Jackman 2008;

Horrocks, Smith, Nichol and Wallace 2008; Horrocks and Wosniak 2008; Horrocks et al. 2004,

2012) has sampled a range of agricultural features such as ditches, stone walls and terraces for

preserved starch, as well as the surrounding landscape. Balme and Beck (2002) sampled

residues on artefacts and sediments to discuss inter-site activity areas within a rock shelter at

Petzeks Cave in NSW, Australia. Similarly, sampling of sediments from prehistoric features has

been integrated into archaeological projects carried out in Asia and the New World, particularly

in locations where macrobotanical preservation is low. This analysis has led to the identification

of functional variation within and between sites (Laurence 2013; Messner, Dickau and Harbison

2008), which has been extrapolated further to discus mobility, and the nature and chronology of

plant domestication (Barton 2005; Holst, Moreno and Piperno 2007; Messner, Dickau and

Harbison 2008; Perry et al. 2007). These examples demonstrate how well-dated and carefully

sampled individual contexts can provide information upon site function.

Stratigraphic column sampling, often within test pits or excavation trenches, provides a

means of establishing plant use over time. The technique is borrowed from palaeoenvironmental

46

research (Pearsall 2000), and involves evenly spaced or continuous samples taken from the

exposed section of excavation units (Coil 2003; Lentfer and Therin 2006; Therin et al.1999;

Torrence 2006b). Sampling generally proceeds from the base of the freshly scraped section and

works towards the top, with samples carefully placed into labelled zip lock bags using cleaned

sampling tools to avoid cross-contamination (Lentfer and Therin 2006:153). Others prefer to

sample in the laboratory environment and use box monoliths to collect sediments in situ (Reitz

and Shackley 2012). Sampling using paleoenvironmental coring techniques is also common

where information is sought upon background environmental and landscape change (Coil 2003;

Horrocks et al. 2011; Therin et al.1999) and is validated by studies of modern environmental

variation within surface samples (Lentfer et al. 2002; Lenfter and Therin 2006).

Sample sizes often vary as it is difficult to gauge the density of starch preserved within

sediments unless a pilot study has been conducted (Torrence 2006b). Most researchers

recommend that more sediment is taken than the standard 1-5g that will usually be processed in

each batch, with standard sample sizes of up to 100g taken from each context or stratigraphic

level (Fullagar et al. 1998:51-2). This enables replication of extraction and identification

processes to confirm results, as well as multiple samples to be taken for the extraction of other

organic material aside from starch such as phytoliths and pollen.

Once these samples have been collected in the field, they are sub-sampled for starch

extraction in the laboratory using one of a number of methodologies. Steps generally involve

sample preparation, disaggregation and deflocculation to break up sediments, the removal of

unwanted particles, slide mounting and viewing; however, there are a number of ways in which

each of these steps can be carried out (Coil et al. 2003; Torrence 2006b). Experimental studies

have demonstrated that many chemicals used during standard paleoenvironmental laboratory

protocols can damage starch, and therefore alternatives must be sought (Crowther 2009;

Torrence 2006b). Crowther (2009) conducted a range of experiments to test a number of

chemicals and processing techniques that had been used previously to extract starch from

sediments and charred residues. These experiments showed that nitric acid, hydrogen peroxide

and heavy liquid in the form of sodium polytungstate (Na6 (H2W12O40)(SPT) had some

damaging effects on starch granules. Instead, Crowther (2009:82-83) recommended a protocol

using simple chemical disaggregation using weak sodium hydroxide in conjunction with mild

agitation and limited sonication within an ultrasonic bath.

Similarly, Torrence and Therin (in Torrence 2006b) tested the effects of Calgon,

caesium chloride (CsCl), and sodium polytungstate— two chemicals used for heavy liquid

flotation on native starch granules. Samples were monitored at regular intervals up to one week

by sub-sampling. The results of these experiments contrasted with Crowther’s (2009) in that

sodium hydroxide did not have any corrosive effect on granules, nor did this chemical affect

47

starch quantities when sub-samples were compared over time (Torrence and Therin, in Torrence

2006b:156-7). Caesium chloride was found to have a deleterious effect, but this peaked after

five hours of exposure and starch quantities subsequently stabilised. Overall, the 5% dilution of

Calgon was found to be the most damaging chemical, with only 59% of starch remaining after

five hours of exposure. Torrence and Therin (in Torrence 2006b:157) concluded that other

means of deflocculation be explored in the future. The difference between these results for

sodium polytungstate may be explained by another study on taphonomy in the laboratory by

Korstanje (2003), where Zinc Iodide (ZnI2) was assessed as another potential means of heavy

liquid separation. In this experiment, the use of the chemical was constant, while other variables

such as humidity and temperature varied. Korstanje (2003:116) concluded that Zinc Iodide

could only be considered destructive to starch when combined with humidity and heat during

slide preparation and scanning.

Heat is a variable that has been debated by starch analysts with regard to starch

extraction protocols. As discussed earlier, starch gelatinises or melts when exposed to heat and

moisture, and so these environments are mostly avoided in starch extraction protocols.

However, some protocols suggest that sediments are dried prior to processing to ensure that

weights of sediment remain consistent within samples, and also to reduce excessive moisture

that can affect the concentration of chemicals (Lentfer and Therin 2006:160). It is argued that

heat should be kept at a maximum of 40ºC, when a longer period of exposure is required. This

temperature limit also applies to slide drying, where it is recommended that slides are either

dried slowly at very low temperatures on a hotplate (Lentfer, pers comm. 2008), or covered at

room temperature (Coil et al. 2003; Kortanje 2003).

Variation within processing protocols also reflects the type and contents of the

sediments that are being processed. Some chemicals such as hydrogen peroxide are useful

oxidising chemicals to disaggregate sediments high in clay or organic content, or charred

residues (Crowther 2009; Lentfer and Therin 2006). Calgon is also often used as a deflocculant

to separate clay particles. Where these are not required, many protocols simply use heavy liquid

flotation and sieving to separate starch from sediments (Atchison and Fullagar 1998; Barton et

al. 1998; Fullagar et al. 1998; Messner 2011; Therin et al. 1999; Therin 1994). Many

researchers are also quick to point out that techniques are often only in early stages of

development and so protocols are only broad outlines of principles rather than definitive

methodologies (Fullagar et al. 1998; Korstanje 2003; Therin et al. 1999). Protocols for starch

extraction must constantly be updated in light of new data about starch modification that is

produced both in the food sciences and archaeobotany. Microwave extraction is a new technique

that is currently being tested, especially where fast results are required (Parr 2002, 2006), and

involves the pressurization and digestion of organic material within the microwave before

sieving to capture microfossils.

48

Chapter 4 Reviewing Parenchyma

The analysis of archaeological parenchyma (or charred vegetative storage tissues) has been

under-researched within archaeobotany due to a prevailing view that these remains do not

preserve in tropical conditions. Where these remains are preserved in archaeological contexts,

they can be extracted through a combination of excavation and flotation practices. When

analysed, these data can then provide information upon the diet and subsistence practices of

prehistoric cultures that utilise root and tuber crops, such as those in the Pacific. Additionally,

the presence of charred parenchyma can be used to infer inter- and intra-site function involving

food processing and cooking areas, and also the timing and geographic range of crop dispersal

and population migration. Hather (2000) in his seminal guide suggests compiling a comparative

collection of relevant domestic and wild species, in the form of both histological thin sections

and experimentally charred samples that should be analysed using Scanning Electron

Microscopy (SEM).

Fresh and charred parenchyma morphology

Few archaeobotanical studies have sought to establish the range of morphological

characteristics of vegetative storage parenchyma that are distinctive at various taxonomic levels.

Most of what is currently known has been sourced from biology and agricultural sciences.

Histological thin sectioning and Scanning Electron Microscopy (SEM) have enabled gross

morphology and anatomical characteristics of plant roots and tubers to be studied in detail, and

have been replicated by archaeobotanists. Basic anatomical characteristics can be divided into

those observed in root-derived tissues and those from stem-derived tissues (Hather 2000; Lebot

2009). A root is the underground portion of the main axis of the plant or branches of the axis,

while a stem is the portion of the main axis or branch that is leaf and flower-bearing (Pearsall

2010:153). When stems occur underground, such as corms and stem tubers, they retain many of

the anatomical leaf-bearing features including buds and internodes (2010:153; Pate and Dixon

1982:14-21). In contrast, roots lack these gross morphological features. Primary root tissues

within dicotyledons and monocotyledons share many morphological similarities (Barlow 1987;

Hather 2000:61). A central stele contains the vascular tissues of the phloem, xylem and the

vascular cambium surrounded by a layer of endodermis and pericycle enclosed within the outer

cortex and epidermis. Secondary root cellular structure in gymnosperms and dicotyledons

displays secondary growth within the secondary vascular tissues of the phloem and xylem

originating from the vascular cambium, and a periderm originating from an outer cork cambium

(Hather 2000: 61; Pearsall 2010:153). Monocotyledons do not exhibit secondary root growth.

Stem tissues contrast with roots, consisting of a much simpler anatomy. An outer epidermis

surrounds a region of ground tissue or cortical parenchyma, through which runs vascular tissues

and the stele (Hather 2000:49). Within these broad anatomical distinctions, taxa differ

49

morphologically due to the function and growth context of these various tissues. Cell shape,

size, wall characteristics, and arrangement within the ground and vascular tissues vary across

taxonomic levels, along with the arrangement of vascular tissues and cavities within the stele

(Hather 2000; Pearsall 2010:158). Patterns of tertiary growth can also differ, sometimes even at

the level of individual plants due to localised environmental conditions.

Archaeobotanists by necessity must take these morphological analyses a step further to

compare fresh and unaltered parenchymatous tissues with experimentally charred material that

is more likely to resemble the preserved botanical remains found in archaeological contexts. A

small number of studies have attempted to replicate archaeological charring conditions through

the use of muffle furnaces or experimental hearths (Hather 1993, 1994a, 1994b, 2000; Mason et

al. 1994; Oliveira 2008, 2012; Paz 2001; Pryor et al. 2013). Samples of vegetative storage

parenchyma from species that had geographic ranges pertinent to the locations of archaeological

projects were selected, charred under various conditions and then observed using combinations

of light microscopy and SEM. Many distinctive changes in morphology were noted; particularly

where samples were charred from fresh state and so still had high moisture content, as opposed

to being dried prior to exposure to heat (Hather 1994a, 1994b, 2000; Paz 2001).

Alterations of vegetative storage tissues occur during charring or desiccation, but vary

according to charring conditions. Variables such as temperature, period of exposure to heat and

oxidising conditions (such as immersion in substrate) can create further modification of tissue

morphology (Hather 1991:663; Hather 1993; Pearsall 2010). Features such as the creation of

tension fractures and vesicles, the deterioration and subsequent transformation of the phloem

into cavities or solid carbon, and modification of cell characteristics such as wall thickening and

compression can alter the original morphology of roots and tubers (Hather 1991:3-8, Paz

2001:88-105). Tension fractures are caused by the ripping apart of tissues along lines of

weakness, while vesicles are created through the dissipation of steam within the tissue (Hather

1994a:54). Lignified tissues such as the xylem are generally preserved during charring, but the

living tissues within the ground tissue and the phloem are either altered or completely

breakdown. The water content of tissues prior to charring can significantly increase the extent to

which these tissues are altered or damaged (Hather 1993:3). It is important that the nature and

scope of these changes is understood when attempting to identify unknown botanical remains

extracted from archaeological or palaeoenvironmental contexts.

Taphonomic factors affecting macrobotanical preservation

Unlike the analysis of starch granules within archaeological and palaeoenvironmental contexts,

the taphonomy of vegetative storage parenchyma is poorly known. This is a direct result of the

lack of archaeobotanical projects targeting the charred remains of these relatively soft tissues

under the presumption that preservation will be low or non-existent. Conditions for preservation

50

of parenchyma are primarily limited to those that either desiccate, water-log or char these

botanical remains (Hather 1991, 1992, 1994, 2000). Another less common form of preservation

includes mineralised or semi-mineralised remains that are either impregnated or coated by semi-

crystalline minerals that protect the soft tissues from fast decay (Paz 2001:40). While wood

charcoal and seeds may change little on preservation (unless compressed), vegetative storage

tissues tend to undergo a number of physical transformations (Hather 1991:662). This is because

roots and tubers have a higher proportion of parenchyma tissues and a smaller portion of cells

with lignified walls than stem wood (Pearsall 2010:161). Experimental charring has emphasised

the nature of some of these changes which include expansion or shrinkage of tissues, the

deterioration or loss of more fragile regions, and fragmentation (Hather 2000:74, 1991:662-3).

The paucity of root and tuber macro-remains in archaeological sites is often directly

related to how these resources are processed and used. As these are generally sources of food

the only part of the organ that often remains is the peel (Allen 1983; Kahn and Ragone 2013;

Pearsall 2010:154). Some root peelings are tough and fibrous but others have periderms that

decay relatively quickly and are very fragile if charred. Other aspects of the biology of roots and

tubers also make any preservation unlikely. For example, if these organs are dropped or

discarded by humans they are often scavenged by animals or are susceptible to agents of decay

due to the high calorific value and moisture content (Holden et al. 1995:777). High moisture

content also makes these organs prone to distortion and fragmentation if exposed to heat,

especially once charred (Holden et al. 1995:777; Pearsall 2010:157). Those fragments or whole

organs of vegetative storage parenchyma that do preserve are most likely roots and tubers that

have been discarded into the fire as spoiled goods or accidentally charred during roasting

(2010:157). Ethnoarchaeological observation in the Philippines has confirmed these as possible

cultural taphonomic processes that enable charred parenchyma to enter the archaeological

record (Paz 2001:80). Charcoal is formed in the reducing conditions within the ash in the base

of a fire or hearth, rather than the oxidising conditions of the open flame which eventually

reduces tissue to ash. Some small dense fragments of tissue can fall through the structure of the

fire into the ash and transform into preserved charcoal (Hather 1991:663).

Hather warns that quantification of taxa within preserved parenchyma is unlikely to

result in meaningful interpretation because the cultural and taphonomic processes affecting the

conditions of preservation are largely unknown (Hather 2000:74). However, it is possible to

utilise some of the current data about macrobotanical preservation and post-depositional

processes derived from studies of wood charcoal or anthracology. Thery-Parisot and others

(2010) describe the range of ‘filters’ that botanical remains will pass through before being

incorporated into palaeoenvironmental or archaeobotanical reconstructions. These include

societal filters such as selection, hearth maintenance and storage; combustion filters such as

anatomical changes and differential fragmentation; depositional and post-depositional filters

51

include anthropogenic factors, mechanical factors and diagenesis; and archaeological or

anthrocological filters including sampling, identification and quantification (Thery- Parisot et al.

2010:143). Post-depositional filters can be broken down into specific cultural processes such as

trampling, re-working and sweeping, and natural taphonomic agents such as bioturbation,

atmospheric factors, mechanical constraints that cause pressure or friction in the sediments and

can induce chemical alteration, water and the pH of soils (Thery-Parisot et al. 2010:147-150).

Where these process act homogenously within a particular context, they will not affect the

palaeoecological signature, but this is rare and differential preservation can often be observed

within these records.

These post-depositional processes can lead to vertical and horizontal migration of

remains as well as fragmentation and disappearance (Paz 2001, 2005; Oliveira 2008; Hather

1994, 1995). Nelson (1992) and Greenlee (1992) assessed the nature of downward displacement

of macrobotanical remains within shell midden contexts. Each argues that the ratio of shell to

soil matrix will affect the porosity of the midden, and thus also the amount of movement that is

possible (Greenlee 1992:262; Nelson 1992:254). As a general rule, particles smaller than 2mm

are most susceptible to movement through mechanical processes, as well as bioturbation by

roots, earthworms and burrowing animals (Nelson 1992:254; Thery-Parisot et al. 2010:147).

Paz (2001) also explores the role that soil matrix can play in the preservation and movement of

macrobotanical remains. He argues that the compaction of clay soils inhibit matrix mixing

except where bioturbation has occurred, but agrees with Nelson (1992) and Greenlee (1992) that

the porosity of shell midden and also sandy deposits allow greater degrees of turbation and

downward displacement (Paz 2001:40).

Questions of context security can also be addressed through assessment of the forms

and taxa of preserved macrobotanical remains within a given strata. Purely charred remains can

be considered reasonably representative of an in situ deposit, especially where upper layers do

not contain any untransformed or intrusive remains that have not undergone charring,

desiccation, water-logging or mineralisation (Paz 2001:262). Where downward percolation has

occurred, the distribution of seeds and small charcoal should be indicative of this movement,

with greater densities of remains in lower levels of particular deposits or facies within shell

middens (Nelson 1992:243). Post-depositional homogenisation by chemical processes such as

prolonged submersion in brackish groundwater can also occur and mask variability in separate

and disparate depositional events (Nelson 1992:251). These studies argue that by assessing the

context, sedimentary matrix, and nature of botanical remains, some natural and cultural post-

depositional taphonomic processes can be recognised and incorporated into the interpretation of

the archaeobotanical record.

52

Macrobotanical preservation within tropical climates like those in the Pacific is

generally thought to be poor. However, a number of archaeobotanical projects in the Asia-

Pacific region have proven that these conditions do not necessarily inhibit long term

preservation of soft tissues (Allen 1983; Barton and Paz 2007; Hather 1991, 1992, 1994a,

1994b, 1995; Paz 2001, 2005). Desiccated remains are rarely found unless in caves or rock-

shelters. Water-logged remains are a more common form of soft vegetative tissue recovered in

the region (Hather 1992:71). Anaerobic brackish lagoon settings have preserved large

assemblages of botanical remains within modern beach deposits formed by clay erosion. For

example nuts and other large seeds were preserved within these conditions at the site of

Talepakemalai on Eloaua Island in the Mussau Island group (Hather 1992; Kirch 1989). Charred

remains of roots, tubers, wood, seeds and nuts form the majority of preserved plant tissue found

in archaeological and palaeoenvironmental contexts. Within these remains, fruits, roots and

tubers are less common, but have been extracted and identified on a number of occasions within

rock shelter deposits (Hather and Kirch 1991; Oliveira 2008, 2012; Paz 2001), shell middens,

house floors (Coil and Kirch 2005; Kahn and Ragone 2013; Yen 1974) and dry sandy open sites

(Hather 1994).

Collection and sampling of parenchyma

Preserved vegetative storage parenchyma can be extracted from archaeological contexts using

established archaeobotanical methods for collection of macrobotanical remains. These usually

involve flotation, or wet or dry-sieving of excavated material, alongside collection of material in

situ (Hather 1994a; Pearsall 2010; Thompson 1994:14). Sieving involves the manual agitation

of material to loosen sedimentary aggregates and allow smaller particles to fall through the

various sized meshes, retaining a portion that contains botanical material (Hageman and

Goldstein 2009:2846).This separation is more effective and less biased than collection of

botanical material by eye during excavation. Dry-sieving is not always effective when

processing clay or silty sedimentary matrices, and so wet-sieving or flotation is more commonly

used in these circumstances. Wet-sieving utilises water to further breakdown tough aggregates

or sediments that have high clay content. Limiting factors affecting the effectiveness of dry or

wet-sieving techniques are the size of the mesh used which can bias the types of remains

collected, and the amount of force used to push material through the mesh can also damage or

fragment preserved botanical remains (Pearsall 2010:13).

Water flotation utilises differences in density of organic and inorganic material to

separate organic material such as charred botanical remains from the soil matrix. When carried

out on a large scale, this technique can separate much higher quantities and range of botanical

material than sieving alone (Pearsall 2010). Mechanical bulk flotation devices can be employed

to process large amounts of sediment where water is freely available or where equipment is

available for water recycling (Hageman and Goldstein 2009; Pearsall 2010); however, these

53

machines can increase the risk of charcoal fragmentation. These systems use flowing water to

break up sediments and release any charred botanical remains that have a specific gravity or are

less dense than water to float to the surface. The remains are caught in sieves with varying mesh

diameters to create flot fractions of different sizes (Pearsall 2010:50-52). Mechanical systems

are designed to limit the need for extra personnel to operate them, but must be overseen for

maintenance and to collect samples (Hageman and Goldstein 2009:2847-8). Bucket flotation is

often used where equipment and access to water is limited (Fairburn 2005b; Mason et al.1994;

Oliveira 2008; Paz 2001). These tub or bucket systems involve manual agitation of sediments,

with muslin cloth pegged into a bucket replacing sieves to catch botanical remains that are

decanted from the surface of the diluted sediment. Heavy residue remains in the bucket, which

is then either discarded or wet-sieved, to collect any remaining botanical or artefactual material.

Comparisons of the flotation techniques have demonstrated the effectiveness of the mechanical

systems (40-100%) over the bucket systems (6-100%) in terms of recovery rates (Wright 2005).

It has been argued by some archaeobotanists that dry-sieving is the most appropriate

technique for the separation of vegetative storage parenchyma due to the fragility of these soft

tissues when preserved in charred, desiccated or mineralised forms (Hather 2000:74). Other

studies have demonstrated that the utilisation of both sieving and flotation can result in the

recovery of increased quantities and also greater taxonomic diversity (Fairburn 2005b;

Hageman and Goldstein 2009). Both techniques have advantages in the separation of particular

types of botanical remains and specific taxa. Flotation enables the collection of material with

low specific gravities such as many seeds, while sieving can facilitate the collection of endocarp

and wood that is often too dense to be recovered through flotation. A combined approach is

essential when consideration is given to the fact that that different environmental conditions

during carbonisation can cause some botanical remains to vary in density, and thus affect the

odds of recovery through flotation (Wright 2005:24).

The selection of a sampling strategy can also influence the recovery of botanical

remains using techniques highlighted here. It is most often impractical to process all excavated

material from within large-scale projects for all size-classes of preserved botanical remains, and

an appropriate sampling regime must be chosen that enables the particular research questions to

be answered. Lennstrom and Hastorf (1995) caution against taking the ‘feature bias’ approach

that targets only features or areas of concentrated carbon, as it is just as relevant to discover

areas that do not contain botanical material. The most common macrobotanical sampling

techniques are the ‘blanket sampling’ strategy, whereby a sample is taken from every excavated

context and feature (Fairburn 2005b:10; Pearsall 2010:66-68). These include ‘scatter’ or

composite sampling where small amounts of matrix are gathered throughout a context and

combined in the same collection bag, where samples derive from a column or sequence of

deposits, and point bulk sampling of precisely located areas within a context (Pearsall 2010;

54

Wright 2005:20). Comparison of these techniques indicate that composite samples tend to

recover higher quantities and diversity of charred material, but had a smaller range of variability

within the density of material compared to point bulk sampling. Pearsall (2001:71) argues that

this indicates that scatter samples captures a greater range of actions and places within an

occupation level, but may also be a biased approach to sampling.

Sampling strategies involve the collection of a small amount of material considered

representative of a particular context, but the way and form in which the sample is measured can

also vary, and influence archaeobotanical interpretation. Sample size is usually measured by

weight or volume, although these can both be influenced by the amount of moisture within the

sedimentary matrix (Wright 2005:20). Even very small amounts of water can increase the

weight of soil, for example 1ml of water at 4ºC weighs 1g. Volume is often measured using a

calibrated bucket, but wet matrix can be harder to pack into these buckets and thus more

difficult to accurately measure. Wright (2005) demonstrated this difference in volume by also

comparing the types of sediment being measured when wet and dry or partially dried. Clay

sediments had an average increase in volume of 25%, while silty sediment only increased 9%

and sand was almost exactly the same, with an increase of only 1%. These results indicate that

consistency is required to ensure that sample sizes can be considered representative and are

comparable (Lennstrom and Hastorf 1995:705). Despite this, repeated wetting and drying of

samples is not recommended, as this can weaken the cellular structure of charred remains and

increase rates of fragmentation (Greenlee 1992; Hather 2000; Paz 2005).

Parenchyma identification

Researchers, both in the Pacific and elsewhere, targeting the extraction and identification of

vegetative storage tissues have emphasised the need to define the criteria upon which taxonomic

identification is based. At the most basic level, charred vegetative storage parenchymatous

tissues can be distinguished from wood charcoal based on several gross morphological and

anatomical characteristics (Hather 1991:673; 1993:3, 2000; Pearsall 2010). These include:

Fragments are often rounded in shape, unless recently fractured, as corners and

protruding tissues tend to be removed cell by cell.

Cells are mostly rounded in shape and more or less isodiametric in dimension, with very

few highly elongated cells resembling vessels or tracheids in wood.

The texture of parenchymatous tissues is usually dull but some areas will be dense and

reflective where vascular tissues or schlerenchyma has formed solid carbon.

Charred vegetative parenchymatous organs often contain regular or irregular cavities,

caused by the evaporation of moisture, that are identifiable under low power

microscopy.

55

Beyond these basic characteristics of charred vegetative parenchymatous tissues, the

preservation and size of fragments determine the level of taxonomic identification that can be

achieved. Archaeobotanists are currently divided over the diagnostic value of morphological

and anatomical characteristics, and how to define confidence in classifications based on these

attributes. Most agree that by studying the overall form of root and tuber material, external

characteristics, anatomical structure, and alteration of tissues through charring process, it is

often possible to identify archaeological material (Paz 2001; Pearsall 2010), but caution against

attempting precise identification on poorly preserved remains that lack features of diagnostic

value. Hather (2000:72-73) argues that for a character to be diagnostic within the scope of a

comparative collection, it should satisfy four conditions. Firstly, it should be common enough to

be found in all recovered fragments that have this characteristic. Secondly, it should be easily

observable and thus have survived preservation and post-depositional processes. Thirdly, it

should be a stable character that does not vary infraspecifically. Finally, the character should

vary between species or higher level taxonomic groups. High confidence identifications are not

usually based on single diagnostic characters; rather remains are classified using a range of

different attributes.

Pioneering research by Hather (1991, 1993, 2000) established the overall diagnostic

value of the morphological and anatomical components of roots and tubers through analysing

the rate of preservation, frequency of occurrence within an organ, stability and range of

variation of each. In general he argues that characters of the gross morphology and surface

features are rarely found on preserved fragments of parenchymatous tissues from roots and

tuber, unless these organs are small before charring (Hather 2000:73). However, when these are

present these are generally of high diagnostic value. Parenchyma and sclerenchyma cells usually

preserve relatively well, but the range of variation between these is often observed to be quite

low when comparing different taxonomic groups. Vascular tissues also preserve well except

within the secondary growth of roots, but in contrast to ground tissue, mostly varies between

species or higher taxonomic groups.

Paz (2001, 2005) takes these findings further by establishing the range of variation

within the periderm, examples of which have been recovered from several locations around the

Asia-Pacific region (as mentioned earlier), including within his own research. Importantly, Paz

also describes the specific criteria by which remains can be identified to plant taxon, specific

organ or as vegetative storage parenchyma (Paz 2001:82-85). For example, remains can be

identified to a particular taxonomic group if the fragments fit all or most of the features of a

reference species such as cell size, shape, the arrangement of vascular tissues, and crystal or

starch grain morphology (Paz 2001:82). Without preserved cellular structure with observable

shapes, walls, and vascular tissues, remains cannot be identifiable to species or any higher

taxonomic grouping with high confidence. Instead, prefixes such as ‘cf.’ or the suffix ‘type’ can

56

be used to indicate moderate confidence classifications. When these criteria are not met, these

can often still be identified morphologically and artefactually using characters of charring as

root or stem tubers (Paz 2001:83). Aside from morphological and anatomical characters, other

criteria include matching images, illustrations, local or regional flora citations, taxonomic

details of the species, and the geographic distribution of taxa (Paz 2001:71). These criteria

established by Paz for the identification of parenchyma have not been universally adopted by

other researchers, but Oliveira (2008, 2012) has used the same methodology in his research in

East Timor. These criteria were successful in aiding the identification of a number of economic

and supplementary crops within these locations.

57

Chapter 5 Comparative Collection and

Morphometric Studies of Pacific Cultigens

Chapters 3 and 4 of this thesis highlighted the issues and potential applications of starch and

parenchyma within archaeobotany in the Pacific. The biological features of these botanical

remains were outlined, which influence both taxonomic classification and also long term

preservation. Preservation of micro and macrobotanical remains particularly in tropical climates

was discussed, along with other taphonomic factors such as bioturbation and the effects of

cultural processes such as charring and boiling. A number of techniques for the extraction of

starch and parenchyma from sediments were also reviewed. These reviews influenced the

decision to establish a comprehensive reference collection for this study, which incorporated a

detailed morphometric study of both economic and supplementary species from the Kingdom of

Tonga.

Species selection

Ethnobotanical and historical resources were used as guides for the inclusion of species in the

modern comparative collection for this study. The list of crops recorded by early explorers and

missionaries such as Cook (1785), La Perouse (1788), La Billardiere (1793), Wilson (1799),

Mariner (in Martin 1991), Waldegrave (1873), Gifford (1929), Beaglehole and Beaglehole

(1941), and others on Tongatapu, is vital to the development of a comprehensive understanding

of late prehistoric and contact period agriculture in Tonga. Ethnobotanists have attempted to

assess the origins and dispersal of these plants in the Pacific for many years (Whistler 2009,

Yen 1974) and lists of endemic, native, and Polynesian or European introduced species within

Tonga are constantly evolving. An inclusive approach was taken in this study, and so sourced

many economic species that may have reached the Tongan archipelago. Other researchers have

established the value of using ethnographic data as a cautious analogy for the past (David and

Kramer 2001; Wylie 1985), and this information was used to develop an ethnographic baseline

for the development of a comprehensive comparative collection in this study.

Historical and contemporary sources indicate that prehistoric horticulture within the

Tongan archipelago was dominated in late prehistory by a small number of starch-rich crops for

the provision of crucial carbohydrates. The most important of these were a range of yams

(Dioscorea spp.), including D. nummularia, D. esculenta, D. alata, and D. bulbifera. Dryland

production of aroids such as Alocasia macrorrhiza, and Colocasia esculenta were seasonally

alternated with the production of yams within plantations, as was the planting of sweet potato

(Ipomoea batatas) in mounds. Arboricultural production of bananas (Musa spp.), breadfruit

(Artocarpus altilis) and the Tahitian chestnut (Inocarpus fagifer) was also an essential

agricultural component. Supplementary to these core species, was a range of alternative plants

58

that were either cultivated or utilised such as the Ambarella (Spondias dulcis), the elephant foot

yam (Amorphophallus campanulatus) and the Polynesian arrowroot (Tacca leontopetaloides).

These included a number of species that were also part of this transported landscape from

Wallacea and Southeast Asia, but others were native or endemic species that produced roots,

tubers, fruits and seeds that were either edible through processing, or used for other cultural

purposes (such as kava or Piper methysticum, and the fish-poison tree- Barringtonia asiatica).

Plant products fulfilled a number of vital roles within Polynesian society, and so the inclusion of

a range of species within the comparative collection for this study will shed light on the

antiquity of some of these practices with Tongan prehistory.

Field collection

The major portion of the comparative collection used in this study was collected from the island

of Taveuni in Fiji. Approximately 25 species were collected here, with another 15 species

collected in Tonga and Palau. Each vegetative storage organ of the plant was sampled. These

species included a range of both economic and supplementary plants. The comparative

collection built on an earlier range of economic species that had been compiled for the author’s

research in the Marquesas (Ussher 2009). Most islands in Polynesia share the core suite of crops

thought to have either been brought as part of the initial Lapita package (Kirch 1984; Green

1979) or through later migration and interaction, with some environmental restrictions upon

their production capacities. It is therefore relevant to include most of these species from Palau,

Fiji and the Marquesas, in addition to the Tongan specimens, within the comparative collection

for this study.

The major families collected included a range of aroids (Araceae), members of the

Dioscoraceae and Convolvulaceae family, and Moraceae. A survey of Taveuni was carried out

under the guidance of Botanist Bee Gun from the Crisp Lab at the Australian National

University. The help of Botanist and Ecologist, Dr Ann Kitalong, was enlisted in Palau to

survey areas in the Rock Islands and Babeldoab for cultivars. Local names of species were

recorded and used to source plants in communities and plantations. Voucher specimens were

collected for each species included in the reference collection, and are stored either at the

University of Auckland, or the National Herbarium in Canberra. These were air dried quickly

using dry heat in the field, stored within labelled folds of newspaper and compressed using a

wooden plant press (Prebble, pers comm. 2011). The dry heat prevented any mould from

developing upon the specimens from the humid tropical climate.

The organs sampled for starch were stored for transport within alcohol in order to

preserve the original structure (integrity) of the sample, and prevent decay. The samples were

then each labelled and sealed with masking tape to prevent leakage and evaporation during

transportation and storage until laboratory processing commenced back at the Australian

59

National University (ANU). A sample collection sheet was completed for each species,

including details about the geographic location of each plant, a plant morphological description,

and a more specific description of each of the organs sampled using current botanical

terminology. In addition to these specimens collected by the author, a selection of other

economic cultivars was included from a collection housed at the ANU by Douglas Yen.

Samples had been desiccated and powderised before being stored. The desiccated state of these

specimens meant that these could only be included in the starch component of the comparative

collection. Likewise, a number of charred specimens stored at the ANU by Jon Hather were

included in the parenchyma component of the comparative collection.

Laboratory processing of samples

Each of the samples collected in the field was first removed from their original containers and

put into a new sterilised vial with 70% Ethanol and 30% De-ionised water for storage until

further processing began. Each sample was then divided into four sub-samples to allow for

starch extraction, histological thin sectioning and experimental charring for parenchyma from

dried and fresh states.

Figure 5.1 Flowchart showing methodology for the imaging and recording of starch and parenchyma within

the reference collection

Starch processing

The starch samples were processed using a methodology established by Ussher (2009, 2012) in

creating a comparative collection for the Marquesan archipelago, and including methods

suggested in Field (2006). Two methods were used to extract starches from the parenchymatous

tissues of the vegetative organs sampled. The first of these were to simply cut a fresh section

from the organ and press that section onto the slide (Gott in Field 2006). The second was to

gently crush the sample in a mortar and pestle with some distilled water, and then put this

60

extracted residue onto a slide using a pipette (Lentfer, pers.com). The slide was then covered

with a Petri dish until the residue had dried. Glycerol was used as a permanent mountant, due to

the reflective and viscous properties of this compound which allows starch granules to be rolled

and viewed during light microscopy (Field 2006:112). Finally, each sample was covered with a

cover-slip and sealed with nail polish.

Histology

A histological thin section was made from each plant species and organ collected, to

demonstrate parenchymatous cell arrangement, structure and contents. The samples collected

were removed from the 70% Ethanol, and a small 1cm cubed fragment was taken from each

sample and placed into a mixture of 95% (70% dilution) alcohol, 1% glacial acetic acid, and 4%

formaldehyde. This fixative formula was recommended by Hather (2000:78) and is known as

FAA (Formalin-Acetic-Alcohol) (Miksche and Berlyn 1976:30). This fluid is stable, has a good

hardening action and material can be stored in it for years. The samples were left in the FAA

mix fixative for approximately two weeks, by which time the organs had soaked up the mixture

and partially solidified/preserved as dead plant tissue. This solution enabled greater precision

during microtomy to cut thin sections.

Thin sections were made by Anne Prins in the Histology Laboratory at the John Curtin

Medical Research Centre. Several methods for processing samples prior to microtomy were

tested. A white potato (Solanum tuberosum) was also preserved in the fixative formula, and then

used to experiment with microtomy and staining. The Standard Bouins Cycle technique was

applied to prepare the samples after they were placed into small histological baskets. This

technique involves several stages of soaking samples in varying percentages of ethanol warmed

to 40˚C, starting with 70% and finishing in 100%, then baths of chloroform at 40˚C and paraffin

wax at 60˚C. These were then placed in the microtome and cut into 5, 8, 12, 15 and 20µm thin

sections. Experimentation with the white potato indicated that the most appropriate section size

during microtomy was 15µm, as thinner sections tended to rip and thicker sections were

difficult to mount onto the slides. The paraffin embedded thin sections were then mounted on

heated slides and placed in xylol to dissolve the wax, and finally washed with 100%, 90% and

70% ethanol, and tap water prior to staining.

As part of the staining process the sections were treated with 3% glacial acetic acid for

three minutes, and then washed well with running tap water. The slides were then immersed in

Alcian Blue (1%) stain with a pH of 2.5 for 30 minutes, washed in running tap water again, and

finally immersed in a Safranin (0.02%) counter-stain for five minutes and then dehydrated.

After staining, the sections were blotted, allowed to air dry and cover-slipped with Leica

Micromount used as a permanent mountant.

61

The experimental thin sections were observed using light microscopy at x100 and x200

magnification. The cell walls were in good condition, and many starch granules were still

visible and displayed birefringence in some samples. The fact that starch was preserved in these

thin sections was surprising, as starch generally gelatinises at between 30-60˚C (Barton and

Torrence 2006). Here the starch was not only still in native condition, but also abundant within

the cell structures. It was therefore decided that the Paraffin embedded preparation was the most

appropriate for the remainder of the samples within the reference collection. The samples were

prepared in the same way as the experimental white potato and then analysed using light

microscopy in the Microscopy Laboratory in the Department of Archaeology and Natural

History at the ANU.

Experimental charring

To understand the morphological changes that occur during charring, plant materials within the

reference collection were experimentally charred in a muffle furnace. These samples were then

compared with the parenchyma cell organisation and structures observed in the thin sections.

Recommended temperatures and length of time for charring vary according to the type of plant

tissue, i.e. woody or non-woody tissue. Orvis and others (2005) suggest charring woody stem

material, soft-leaf tissue, needle-leaf tissue and monocot tissue at 550˚C for only eight to nine

minutes. Boardman and Jones (1990) tested a range of temperatures, times and atmospheric

conditions (oxidised or reduced). It was discovered that most plant components (granules,

glumes, rachis and straw) will carbonise after 1-2 hours at 300-250˚C, with greater distortion at

higher temperatures even within shorter time periods (1990:5-9). Similarly, Wright (2003)

experimented with charring achenes, kernels, seeds and rind segments of a variety of species.

Variables tested included thermal atmosphere, temperature, duration and moisture content.

Overall, some generalities could be made regarding the carbonisation process including that the

higher the temperature, and longer the exposure, the more likely the specimen will ash rather

than carbonise, and that moist specimens generally survived oxidation better than dry samples.

Finally, a reducing atmosphere was more conducive to preservation by carbonisation than

oxidation (2003:582). The results of these previous studies were used to determine the

techniques used within the current research.

Two small 1cm cubed samples were cut from the remaining plant material for each

sample, and wrapped in tin foil. One sub-sample of each sample was placed into large tin trays,

and then put into an incubator at 60˚C for 48 hours to dry. The second sample was placed into a

pre-heated muffle furnace at 300˚C for 2 hours (Hather 2000:85), or until the samples had

turned to charcoal (Boardman and Jones 1990:3). They were then removed from the furnace and

cooled. Once dried, the remaining samples were also charred in the furnace. All samples were

then fractured to reveal a flat plane that could be viewed using Reflected light microscopy and

Scanning Electron Microscopy (SEM) (Hather 2000:76).

62

Recording

Light microscopy

Starch

Light microscopy was used to view and record attributes of both starch residues and also

parenchymatous plant material in the comparative collection. A Leica DM6000 Compound

Transmitted Light Microscope was utilised to analyse the modern starch samples and record 18

attributes of 50 granules from each slides. Images of each grain were taken, and these were then

analysed using ImageJ software to measure specific attributes. These attributes included

maximum length, width, length of the extinction cross, distance between the hilum and end of

the grain, maximum distance between the arms of the cross, maximum angle of the cross, hilum

location, 3D shape, and presence of lamellae, a small or large vacuole, an equatorial groove,

compressed or discoid structure, multiple facets, flat facets, hilum fissures, raphides (calcium

oxalate crystals), and the style of extinction cross.

The inclusion of metric variables has been recommended by a number of previous

morphological studies including that by Torrence and others (2004), and more recently by

Wilson and colleagues (2010) in their study using image analysis to determine morphological

variety within native reference starch. Metric variables enable much greater differentiation

between taxa, and reduce observer bias during classification. Granules were viewed in both

brightfield and cross-polarised light, so that attributes of the extinction cross could be imaged

and recorded. The data collected during light microscopy was then entered into an Excel

database, with a spreadsheet created for each species and organ sampled.

Parenchyma The histological thin sections were also viewed using light microscopy. Both transverse and

longitudinal sections were imaged and attributes of the cell structure and arrangement were

recorded. These included descriptions of the boundary tissues such as the epidermis, periderm

and cortex, general ground or conjunctive tissues, as well as the vascular tissues. Cell

morphology was recorded through attributes such as cell length, width, shape and dimensions,

as well as cell contents and the presence of inter-cellular spaces. The arrangement and

organisation of vascular bundles were also recorded according to known typologies (Hather

2000). To gain representative samples of tissues, 40 cells from each species and organ, and five

vascular arrangements were measured and described. The images of the thin sections were

viewed and analysed using ImageJ software.

Scanning Electron Microscopy

High resolution, low voltage field emission scanning electron microscopy (HRLVFESEM) was

chosen as one method for the analysis and imaging of the charred parenchyma and starch

samples. This technology provides topographical contrast of small features that are only

63

minimally coated while charging is substantially decreased as a result of lowered beam energy

(Schatten 2008), creating a three-dimensional view of objects. Secondary emission (SE)

signaling was chosen as the amount of SE signal collected from each point is roughly

proportional to the angle between the viewing direction and the normal surface. This type of

image conveys a relatively accurate impression of sample surface topography to the human

brain (Pawley 2008), creating a detailed three-dimensional image of important morphological

features.

Sample preparation

The experimentally charred samples were carefully hand fractured to create a flat plane for

viewing cell structure and arrangement, then attached to an SEM stub using carbon tape. All

starch samples were processed in the following way. A small amount of crushed specimen was

mixed with distilled water onto a small circular glass cover-slip, which was then attached to the

stub using nail polish and left to dry. Carbon tape was placed over the edge of the cover-slip and

the sides of the SEM stub to create a path for the electrons to escape when the sample was

placed in the SEM chamber. All samples were sputter coated with platinum gold at 20

milliamps for 3 minutes to create a relatively even conductive coating for imaging and analysis.

Imaging

The Zeiss UltraPlus FESEM at the Centre for Advanced Microscopy at the ANU was then used

to image each sample at up to 10,000x magnification. A total of nine samples were able to be

placed in the chamber of the SEM at any one time. Each sample was targeted in turn and images

taken of the sample at various magnifications, with appropriate scales embedded. Lower

magnifications of 200-1000x were used to capture images of the cellular tissues and their

arrangements. Higher powered magnification was used to take high-resolution images of

cellular structure, cell contents, and modifications that occur during the charring process.

Imaging was affected by occasionally insufficient or uneven sputter coating of the sample

resulting in the charging of the electron beam which causes images to be blurred in areas. This

could not be avoided in some instances as re-coating with platinum gold would result in further

unevenness and charging. The resulting images of the starch and charred samples of

parenchyma were used to supplement the descriptions of morphology within the comparative

collection, and were vital towards enabling identification of unknown archaeological material in

Part Two of this thesis..

Morphology of native starch

Research within the food sciences has been investigating starch chemistry and physical

morphology for many years. The results of these studies have demonstrated that these aspects of

starch can vary at different taxonomic levels; however it is clear that many species contain a

number of starch morphotypes that are shared with other species (Banks and Greenwood 1975;

Crowther 2012; Henry et al. 2009; Nwokocha and Williams 2011; Parr 2002; Reichert 1913).

64

The compilation of a comprehensive reference collection including both economic and wild

starch-producing species is essential to identify starch preserved within archaeological contexts.

Understanding the characteristics that differentiate between starch morphology at species, genus

or family level, is the only means by which starch extracted from archaeological sediments or as

residues on tools can be securely identified.

Starch morphology

As mentioned previously, a range of starch attributes were analysed for all plant specimens in

the comparative collection. These included a combination of metric, nominal and binary

attributes. It became clear that each specimen (species or organ) contained a range of different

starch morphotypes. Sometimes as many as eight morphotypes were recorded within a single

sample. A signature type was usually present in each specimen and was recognised as being the

most diagnostic morphotype within the random 50 granules recorded. This may not necessarily

be the most commonly represented morphotype. It will be demonstrated here that there is a large

degree of morphological overlap between many specimens within the modern comparative

collection (see Table 5.3). Nonetheless, the identification of these signature types is essential for

establishing an explicit method for the taxonomic classification of unknown archaeological

starch granules.

Hilum features

The hilum is the point from which a starch granule grows and is thus the core of the granule

(Banks and Greenwood 1975). Due to the fact that the hilum is a fixed point on the granule, its

location appears to change as the granule is rolled and viewed from different angles. The hilum

can therefore be used as a point of orientation when describing the three-dimensional shape of

granules. A number of genetic modifications can alter the appearance of the hilum. Hila can

often be observed as a small or large vacuole, or as a fissure or crack on granules. In the

comparative collection developed for use for this study, a large range of specimens contained

starch with a vacuole at the hilum (see Table 5.1, Figure 5.2). Small vacuoles were recorded on

starch morphotypes within 18 specimens, and were commonly seen in 11 of these. All recorded

starch from Piper methysticum had small vacuoles. Conversely, small vacuoles were rare in

most of the Artocarpus and Dioscorea genera, as well as in the seeds of Barringtonia asiatica

and Pteridium sp. Large vacuoles were present in a much smaller number of specimens, and

were common in M. citrifolia and S. dulcis, but rarely observed in B. asiatica, Cyrtosperma

merkusii and Ipomoea polpha. The starch morphotypes of Spondias dulcis all had either a small

or large vacuole, indicating that these are diagnostic traits of starch from this species.

65

Figure 5.2 Diagram showing basic features of starch granule morphology

Fissuring at the hilum was also observed within 18 specimens in the comparative

collection. There are a range of different types of fissuring that can occur within starch (ICSN

2011), and a small number of these were present within the collected specimens. The most

common type was longitudinal fissuring, where the fissure extends along the long axis of the

grain. Nine specimens had granules with longitudinal fissuring, but it was only common in three

species, Amorphophallus paeoniifolius, Dioscorea rotundata and P. methysticum. Radial

fissuring was also identified. This is defined as fissuring that originates at the hilum and spreads

outwards to the margins (ICSN 2011; Reichert 1913), and was commonly recorded within two

species, Ipomoea polpha and Piper methysticum. Transverse fissuring extends at a right angle to

the long axis of the grain (ICSN 2011), and was observed in a total of five specimens (see Table

5.1). Both I. polpha and Spondias dulcis granules commonly feature this hilum type. Stellate

fissuring is another common type recorded within the comparative collection. These star-shaped

fissures were common in three species- I. polpha, P. methysticum and S. dulcis, and rare in

Artocarpus heterophyllus and Inocarpus fagifer.

Several other types of hilum fissuring were identified within a smaller range of species.

Oblique fissures are simple fissures that do not follow any particular axis on the grain (ICSN

2011, Reichert 1913) and were found commonly on granules from Dioscorea rotundata but

only very rarely on Solanum tuberosum. Irregular fissures are those that are uneven in geometry

and were observed on the starch of three specimens; however, this type was only common in I.

polpha and P. methysticum. The presence of a mesial cleft, a large, deep and variably ragged

interior crack that runs parallel to the long axis of the grain (ICSN 2011), was only noted in the

starch of P. methysticum. Likewise, branching fissures were only observed in S. dulcis. These

are fissures that feature subdivisions from the main branch. The final type of fissuring within the

comparative collection is actually classed as an ‘indentation’ at the hilum, and was observed

frequently in A. paeoniifolius but only rarely in I. fagifer.

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Table 5.1 Hilum fissuring of reference species

Lamellae

Lamellae are the growth layers that begin forming at the hilum and disperse towards the

margins of the granule. These were ‘distinct’ in many large starch morphotypes deriving from

the Dioscorea genus including Dioscorea alata, Dioscorea bulbifera, Dioscorea nummularia,

Dioscorea pentaphylla, and Dioscorea rotundata. Distinct lamellae were also visible on all

recorded starch from Curcuma longa and most starch from Musa sp. 1. ‘Indistinct’ or less

prominent lamellae were observed on larger starch morphotypes from the fruit of Artocarpus

altilis, Horsfieldia palauensis, Ipomoea batatas, Ipomoea polpha and Musa sp.2 .Smaller starch

morphotypes, such as those seen within Alocasia macrorrhiza, Colocasia esculenta and

Dioscorea esculenta may have lamellae, but the limitation of light microscopy inhibit the ability

to view these features, and lamellae were also not often visible using SEM.

Three-dimensional shape

Two and three-dimensional shapes are commonly used to describe and discriminate between

starch morphotypes. In this study only three-dimensional (3D) shape was used as the granules

were rolled during light microscopy to optimise visualisation of all planes of the granules.

Fifteen different 3D shapes were observed within the comparative collection. These included a

variety of rounded shapes such as spherical, sub-spherical, ovate, ellipsoidal, sub-ovate,

pyriform (pear-shaped), reniform (kidney-shaped) and shapes with single or multiple facets such

as dome, hemispherical, prismatic, polyhedral, quadrangular, cylindrical, conical, and prismatic.

The nomenclature used to describe these shapes follow the International Code for Starch

Nomenclature (ICSN) compiled in 2011 with some modification.

Rounded granules were observed within 27 of the 29 specimens within the comparative

collection (see Table 5.2). The two species that did not have rounded starch morphotypes were

D. esculenta and C. longa. The most commonly observed shape was spherical or “…a sphere in

Longitudinal Radial Oblique

Amorphophallus paeoniifolius Artocarpus heterophyllus Dioscorea rotundata

Artocarpus altilis seed Barringtonia asiatica fruit Solanumtuberosum

Dioscorea nummularia Cyrtosperma merkusii

Dioscorea rotundata Dioscorea alata Indentation

Inocarpus fagifer seed Dioscorea bulbifera Amorphophallus paeoniifolius

Musa sp. 2 Ipomoea polpha Inocarpus fagifer seed

Piper methysticum Piper methysticum Transverse

Tacca leontopetaloides Barringtonia asiatica fruit

Xanthosoma sagittifolium Stellate Dioscorea rotundata

Irregular Artocarpus heterophyllus Ipomoea batatas

Cyrtosperma merkusii I.fagifer seed Ipomoea polpha

Ipomoea polpha Ipomoea polpha Spondias dulcis

Piper methysticum Piper methysticum Branching

Mesial cleft Spondias dulcis Spondias dulcis

Piper methysticum

67

which all radii are equal length.” (Reichert 1913), with a total of 22 specimens containing

starch that matched this description. Within these specimens were members of a range of

different families, and so there does not appear to be any diagnostic value in this shape for

taxonomic classification. Likewise, sub-spherical granules were present within 15 specimens

from the Anacardiaceae, Araceae, Convolvulaceae, Dioscoreaceae, Lecythidaceae, Moraceae,

Musaceae, and Solanaceae. These are spherical granules with some small degree of curvature or

are scalene, where all three main diameters are of unequal length. Also present in a large

percentage of the reference collection were elongated granules which tend to be high in amylase

(Gott et al. 2006). Ovate (n=16), subovate (n=2), and ellipsoidal (n=9) granules were commonly

observed within members of the Dioscoreaceae and Musaceae families. These are distinguished

from one another based on the diameter of the proximal, mesial and distal ends of the grain.

Ellipsoidal granules have both distal and proximal ends equal in size, while ovate granules tend

to be more egg-shaped with one end wider than the other. Sub-ovate are elongated granules with

the same variation as described for sub-spherical granules. Other variations to these rounded

granules included reniform or kidney-shaped granules, and pyriform or pear-shaped granules.

These differ from the sub-ovate and sub-spherical granules based on a larger degree of curvature

(reniform) and scalar width variation (pyriform). Pyriform granules were only recorded in those

specimens belonging to the genus Musa, while reniform granules were present in five different

specimens representing four different families including Dioscoreacae, Convolvulaceae,

Musaceae, and Solanaceae.

More angular starch shapes were also very common within the comparative collection.

Twenty eight of the 29 specimens had at least one angular morphotype. The only species that

did not was Dioscorea pentaphylla. These shapes vary in the nature and number of straight or

rounded sides (facets) that define the margins and diameters of the granules. Angular granules

have been formed in compound starch granules, where a number of granules are clustered

together within the parenchymatous cells, creating pressure facets. Single faceted 3D shapes

include dome and hemispherical granules, which are differentiated from one another based on

elongation. A domed granule is half an oval, while a hemispherical granule is half a sphere.

Domed granules were present in 12 specimens, while hemispherical granules were slightly more

common, being recorded within 15 specimens. Four of the five aroids, and both members of the

Artocarpus genera within the comparative collection contained hemispherical granules. The

remaining aroid, Xanthosoma sagittifolium, instead had dome-shaped granules. Some specimens

contained both shapes, including Artocarpus heterophyllus, Amorphophallus paeoniifolius, the

seeds of Barringtonia asiatica, Cyrtosperma merkusii, Morinda citrifolia and Piper

methysticum.

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Table 5.2 Three-dimensional shapes of reference species

Multi-faceted angular shapes recorded included conical, cylindrical, polyhedral,

quadrangular, and prismatic. A number of specimens contained starch that could be described as

conical, having a flat circular base and a tapering top. These included Curcuma longa, most of

the members of the Dioscorea genus apart from D. pentaphylla which has more ovate granules,

both Musa spp., and Solanum tuberosum. Cylindrical granules fall part way between rounded

and angular, being described as having “…a circular base and top, both of equivalent size.”

(Reichert 1913). This shape was not commonly observed, and was present only in three

specimens. Four specimens contained granules that had six sides, with four being elongated, and

thus could be described as quadrangular. Within these four specimens, less than five of these

granules were observed. The most common multi-faceted angular shape by a significant margin

was polyhedral. Polyhedral granules are defined as “…having many faces that are not

necessarily of the same two dimensional shape.” (Reichert 1913). These were recorded in all of

the aroids, several members of the Dioscoreaceae family, and a range of other Monocots and

Eudicots totalling 15 specimens.

Dome Reniform

Amorphophallus paeoniifolius Ipomoea batatas Artocarpus heterophyllus Dioscorea nummularia

Artocarpus altilis fruit Inocarpus fagifer seed Amorphophallus paeoniifolius Dioscorea pentaphylla

Artocarpus altilis seed Ipomoea polpha Barringtonia asiatica fruit Ipomoea polpha

Artocarpus heterophyllus Morinda citrifolia fruit Barringtonia asiatica seed Musa sp. 1

Barringtonia asiatica fruit Musa sp. 1 Cyrtosperma merkusii Solanum tuberosum

Barringtonia asiatica seed Piper methysticum Horsfieldia palauensis

Colocasia esculenta Pteridium sp. Ipomoea polpha Sub-ovate

Cyrtosperma merkusii Spondias dulcis Morinda citrifolia fruit Musa sp. 1

Dioscorea nummularia Solanum tuberosum Musa sp. 1 Solanum tuberosum

Dioscorea pentaphylla Tacca leontopetaloides Piper methysticum

Horsfieldia palauensis Xanthosoma sagittifolium Pteridium sp.

Xanthosoma sagittifolium

Alocasia macrorrhiza Dioscorea rotundata Alocasia macrorrhiza Inocarpus fagifer seed

Amorphophallus paeoniifolius Horsfieldia palauensis Artocarpus altilis fruit Ipomoea polpha

Artocarpus altilis fruit Musa sp. 1 Artocarpus heterophyllus Musa sp. 1

Artocarpus altilis seed Musa sp. 2 Barringtonia asiatica fruit Musa sp. 2

Dioscorea alata Piper methysticum Barringtonia asiatica seed Piper methysticum

Dioscorea bulbifera Pteridium sp. Dioscorea bulbifera Spondias dulcis

Dioscorea nummularia Spondias dulcis Dioscorea rotundata Solanum tuberosum

Dioscorea pentaphylla Solanum tuberosum Ipomoea batatas

Alocasia macrorrhiza Dioscorea bulbifera Alocasia macrorrhiza Horsfieldia palauensis

Amorphophallus paeoniifolius Ipomoea batatas Amorphophallus paeoniifolius Ipomoea batatas

Artocarpus altilis fruit Inocarpus fagifer seed Artocarpus altilis fruit Inocarpus fagifer seed

Artocarpus altilis seed Morinda citrifolia fruit Artocarpus altilis seed Morinda citrifolia fruit

Artocarpus heterophyllus Piper methysticum Artocarpus heterophyllus Pteridium sp.

Barringtonia asiatica seed Spondias dulcis Colocasia esculenta Tacca leontopetaloides

Colocasia esculenta Tacca leontopetaloides Cyrtosperma merkusii Xanthosoma sagittifolium

Cyrtosperma merkusii Dioscorea esculenta

Ellipsoidal Conical Quadrangular Pyriform

Barringtonia asiatica fruit Curcuma longa Artocarpus altilis seed Musa sp. 1

Barringtonia asiatica seed Dioscorea alata Artocarpus heterophyllus Musa sp. 2

Dioscorea bulbifera Dioscorea bulbifera Dioscorea esculenta

Dioscorea nummularia Dioscorea nummularia Ipomoea polpha

Ipomoea polpha Dioscorea rotundata Cylindrical Prismatic

Musa sp. 1 Musa sp. 1 Musa sp. 2 Xanthosoma sagittifolium

Musa sp. 2 Musa sp. 2 Spondias dulcis

Pteridium sp. Solanum tuberosum Tacca leontopetaloides

Spherical

Ovate Sub-spherical

Hemispherical Polyhedral

69

Modifiers of shape

These three-dimensional shapes can be altered by several other morphological attributes.

Faceting was discussed above in terms of the development of overall shapes when granules are

formed in compound clusters. Sometimes these ‘pressure facets’ are minimal, and only create

slight impressions on the sides of granules. These granules are usually rounded in shape but

have one or two pressure facets on the margins. Additionally, some dome or hemispherical

granules can have an additional one to two pressure facets where these granules have been

formed in clusters of three granules. They still retain the shape of half a sphere or oval. These

types of pressure faceting are common in Amorphophallus paeoniifolius, Barringtonia asiatica,

Cyrtosperma merkusii, Inocarpus fagifer, Ipomoea batatas, Ipomoea polpha, and Piper

methysticum.

A small number of specimens within the comparative collection contained granules that

were ‘compressed’ so that the granules had a smaller dimension in one plane than the other.

These granules had to be consistently rolled to view this modification of shape in profile. Three

of the yams- Dioscorea alata, Dioscorea bulbifera, and Dioscorea rotundata, and a ginger-

Curcuma longa, all have conical or ovate starch granules that are frequently compressed. In

addition, both Musa spp. within the comparative collection also have compressed forms, but

these are less commonly observed than non-compressed granules. Equitorial grooves often

coincide with compressed granules or those that have uneven dimensions in different planes,

and can be seen as a fold that runs along the long axis of the granules when these are turned on

edge (ICSN 2011). This feature was common in Dioscorea rotundata and noted in Artocarpus

altilis, Amorphophallus paeoniifolius, Dioscorea alata and Piper methysticum.

Several shape modifications were restricted to only one or two particular specimens

within the comparative collection, and so can be considered diagnostic attributes of starch

morphotypes. The first of these were ‘projections’, which were defined as areas that extend

beyond the main surface of the grain (Reichert 1913), and were present on all recorded granules

from C. longa, and a small number of granules of Dioscorea pentaphylla. The conical starch

granules deriving from these specimens also had sharply tapering tips that differentiated these

from granules seen in other specimens. The starch of Morinda citrifolia were often noticeably

‘concave-convex’ where one side curves inward and the other curves outward (ICSN 2011),

creating a hollowed appearance. Finally, the conical starch of Dioscorea bulbifera each had a

distinctive ‘bend’ at the proximal end of the granule just below the hilum. This was sharper than

a ‘curve’ which is defined as a smooth bend in the form of the granule (Reichert 1913).

Granule length and width

The maximum length of starch granules is used by many starch analysts to identify unknown

archaeological starch as a univariate statistical technique within an assemblage-type approach

(Field et al. 2009; Therin et al. 1999). Following these studies, the range of granule lengths

70

within the comparative collection were analysed and compared as assemblages of each species

(see Figure 5.3). Most of the recorded starch within the comparative collection falls into the 8-

25µm range (86% of species), and due to the relatively narrow range there is a significant

amount of overlap between specimens. Only a small number of specimens have ranges that are

larger or smaller than this. Several of the yams, Dioscorea pentaphylla and Dioscorea

rotundata, as well as both Musa spp., Curcuma longa, Ipomoea polpha and Solanum tuberosum

all have maximum lengths that could exceed 40µm. Of these, the Dioscorea spp. are the only

specimens that have an average length above 40µm. Overall, Dioscorea pentaphylla has the

largest starch within the comparative collection, with an average length of 90µm, and a

maximum of 145µm and are therefore taxonomically distinctive. On the smaller end of the

spectrum, several specimens have starch morphotypes that can range below 8µm. These include

Artocarpus altilis seed and fruit, Artocarpus heterophyllus, Alocasia macrorrhiza, Colocasia

esculenta, Cyrtosperma merkusii, Dioscorea bulbifera, Dioscorea esculenta, Horsfieldia

palauensis, Inocarpus fagifer, Ipomoea batatas, Ipomoea polpha, Morinda citrifolia, Pteridium

sp., Tacca leontopetaloides and Xanthosoma sagittifolium. The only specimen to have the entire

range of maximum lengths below 8µm is C. esculenta, which has an average length of 4µm.

Despite this, this species cannot be distinguished from others solely on this attribute, as a

number of other specimens have overall ranges that overlap with Colocasia esculenta such as

Alocasia macrorrhiza and Artocarpus altilis.

A study of granule widths revealed that there is substantial variation in the comparative

collection based on this metric attribute. The starch of most taxa had widths between 7-19µm

(93% of species), which is marginally smaller than the range of starch lengths for most species.

However, unlike starch lengths, there is a greater number of specimens that contain starch

smaller or larger than this range (see Figure 5.4). Sixteen specimens have granules that range in

width above 19µm. Dioscorea pentaphylla is once again distinguishable by having the largest

starch granules in this second dimension. A total of 20 specimens contain starch morphotypes

that can range smaller than 7µm, but only six of these specimens have average widths below

this point. The smallest width range was recorded within the starch of Colocasia esculenta

which has a median of 4µm, and a total range of 2-7µm.

Clearly, there is a significant amount of overlap in these two variables in the

comparative collection. Only one specimen can be confidently distinguished from others based

on either of these variables. Dioscorea pentaphylla has starch that ranges larger in length and

width that any other specimens. On the smaller end of the spectrums for both widths and

lengths, C. esculenta consistently has the lowest medians for these attributes, but this species

still overlaps with the total range of others within the comparative collection. Therefore it is not

able to be distinguished solely on these attributes.

71

Other metric variables

In addition to maximum length and width, a number of other metric variables were measured on

all starch granules sampled from each species within the comparative collection. As mentioned

previously, these included the ‘length of the extinction cross’, ‘maximum distance between the

arms of the cross’, ‘distance between the hilum and the end of the granule’, and the ‘maximum

angle within the arms of the extinction cross’. Most of these measurements are not diagnostic of

species on its own when compared through univariate analyses of the starch assemblages in the

comparative collection. These are more relevant when considered in multivariate statistical

analyses as these dimensions are related to the three-dimensional shape and surface texture of

starch granules. Therefore several of these will not be explored here, but instead will be

compared as variables in the multivariate morphometric analysis later in this chapter.

Hilum position can be compared between specimens but only when this is considered as

a ratio between the ‘length’ and the ‘distance between the hilum and the end of the granule’ (see

Figure 5.5). This ratio enables statistical differentiation between starch that is centric (end-on)

or eccentric (side-on). Centric hila are those that have a ratio that falls between 0.5-0.6, meaning

that the hilum is close to the centre of the granule. These granules have been viewed and

recorded end-on. Eccentric hila are those that have a ratio falling in the range of 0.61-1, and

indicate that the granule has been viewed side-on. This is particularly relevant for granules that

vary in dimension across different planes such as ovate or conical granules. When the

distribution of these ranges is compared between specimens, it is clear that most sampled

granules from each specimen have been recorded in both centric and eccentric views. However

a number of specimens were primarily viewed side-on, including C. longa, D. alata, D.

bulbifera, D. nummularia, D. pentaphylla, D. rotundata, Musa spp., S. tuberosum and S. dulcis.

This is most likely a result of the ovate, sub-ovate or conical shape of these granules which

makes them hard or impossible to view completely end-on. Another 18 specimens were

primarily viewed end-on, and this is similarly a result of shape, but in this case granules are

mostly spherical or polygonal and so are even in length across all dimensions. These hilum

position ratios were used within the following multivariate statistical analysis to divide the

starch within the comparative collection into comparable datasets.

72

Figure 5.3 Box plot of starch granule lengths within reference collection

Figure 5.4 Box plot of starch granule widths within reference collection

73

Figure 5.5 Box plot of starch granule hilum position to length ratios within reference collection

74

Table 5.3 Summary of starch morphology within reference collection

Species Organ

Length

range

(µm)

Width

range

(µm)

Length to

hilum position

ratio range

3D shape Other features

Artocarpus altilis Fruit 5-12 3-12 0.5-0.6Hemispherical, ovate, polygonal,

spherical, sub-spherical

Small vacuole and flat single and multiple faceting common.

Equitorial grooves and lamellae rare.

Artocarpus altilis Seed 3-12 3-9 0.5-0.75Hemispherical, ovate, polygonal,

quadrangular, spherical

Flat and curved single and multiple faceting common. Small vacuoles

and longitudinal fissuring rare

Artocarpus

heterophyllusFruit 4-13 3-13 0.5-0.6

Dome, hemispherical, polygonal,

quadrangular, spherical, sub-

spherical

Flat and curved single and multiple faceting common. Small vacuoles

and stellate or radial fissuring rare

Alocasia macrorrhiza Corm 2-10 2-9 0.5-0.6Hemispherical, ovate, polygonal,

sub-spherical

Flat and curved single and multiple faceting common. Simple and

compound grains.

Amorphophallus

paeoniifoliusCorm 12-36 7-30 0.5-0.71

Dome, hemispherical, ovate,

polygonal, spherical

Flat and curved single and multiple faceting and longitudinal fissuring

or indentation common. Equitorial grooves rare. Simple and

compound grains.

Barringtonia asiatica Fruit 8-20 6-20 0.5-0.73Dome, ell ipsoidal, spherical, sub-

spherical

Flat and curved multiple faceting common. Curved single faceting,

large and small vacuoles and radial or transverse fissuring rare.

Barringtonia asiatica Seed 8-20 6-17 0.5-0.78

Dome, ell ipsoidal,

hemispherical, spherical, sub-

spherical

Small vacuole and flat and curved single and multiple faceting

common. Large vacuole rare.

Colocasia esculenta Corm 3-8 2-7 0.5-0.75Hemispherical, polygonal,


Flat multiple and single faceting common. Simple and compound

grains.

Curcuma longa Rhizome 15-60 14-30 0.8-1 Conical All lenticular, lamellae, proximal protrusion and tapered tip.

Cyrtosperma merkusii Corm 5-26 5-26 0.5-0.6Dome, hemispherical, polygonal,

spherical

Small vacuole and flat and curved single and multiple faceting

common. Radial or irregular fissuring and large vacuole rare. Simple

and compound grains.

Dioscorea alata Root tuber 10-25 5-19 0.62-1 Conical, ovateCommonly lenticular and lamellae present. Equitorial groove, small

vacuole and radial fissuring rare.

Dioscorea bulbifera Aerial bulbil 5-30 4-26 0.62-0.96

Conical, hemispherical,

ell ipsoidal, ovate, sub-spherical,

triangular

Commonly lenticular or wedge-shaped, bent with flat multiple and

single faceting and lamellae present and rare radial fissuring.

Dioscorea esculenta Root tuber 3-13 3-11 0.5-0.75 Polygonal, quadrangularFlat and curved multiple and single faceting common. Simple and

compound grains.

Dioscorea

nummularia Root tuber 11-50 10-39 0.62-0.9

Conical, ell ipsoidal, kidney,

ovate, spherical

Lamellae and single flat faceting common. Multiple flat faceting, small

vacuole and longitudinal fissuring rare.

75

Species Organ

Length

range

(µm)

Width

range

(µm)

Length to

hilum position

ratio range

3D shape Other features

Dioscorea rotundata Root tuber 34-95 15-62 0.62-0.94 Conical, ovate, sub-sphericalLamellae present. Commonly lenticular with equitorial groove and

parallel fissuring. Small vacuole rare.

Horsfieldia

palauensis Nut 5-27 4-24 0.5-0.67

Dome, ovate, polygonal,

spherical

Small vacuole and flat multiple and single faceting common. Lamellae

rare.

Inocarpus fagifer Seed 6-21 6-19 0.5-0.6Hemispherical, polygonal,


Small vacuole and flat multiple and single faceting common.

Longitudinal fissuring or indentation rare.

Ipomoea batatas Root tuber 4-17 4-16 0.5-0.6Hemispherical, polygonal,


Small vacuole and flat and curved multiple and single faceting

common. Lamellae and transverse fissuring rare.

Ipomoea polpha Root tuber 7-51 7-46 0.5-0.73

Dome, ell ipsoidal,

hemispherical, kidney,

polygonal, quadrangular,


Small vacuole and stellate, transverse, radial or irregular fissuring

common. Flat and curved multiple and single faceting, lamellae and

large vacuoles rare.

Morinda citrifolia Fruit 5-15 4-14 0.5-0.6Dome, hemispherical, polygonal,

spherical

Large vacuole, concave-convex and curved multiple and single faceting

common. Flat multiple and single faceting rare.

Musa sp. 1 Fruit 9-53 7-32 0.62-0.95

Conical, dome, ell ipsoidal,

kidney, ovate, pyriform,

spherical, sub-ovate, sub-

spherical

Lamellae, flat single faceting and lenticular shape rare.

Musa sp. 2 Fruit 8-61 6-48 0.62-0.92Conical, cylindrical, ell ipsoidal,

ovate, pyriform, sub-spherical

Lamellae and small vacuole common. Flat single faceting, longitudinal

fissuring and lenticular shape rare.

Piper methysticum Primary root 8-26 4-20 0.5-0.6Dome, hemispherical, ovate,


Small vacuole present. Lamellae and longitudinal, stellate, irregular,

radial or mesial cleft fissuring common. Flat and curved multiple and

single faceting, lenticular shape, and equitorial groove rare.

Pteridium sp. Rhizome 4-13 3-11 0.5-0.6Dome, ell ipsoidal, ovate,

polygonal, spherical

Flat and curved single faceting common. Flat and curved multiple

faceting and small vacuole rare.

Solanum tuberosum Stem tuber 11-62 10-42 0.65-0.89Conical, kidney, ovate, spherical,

sub-ovate, sub-spherical

Lamellae present. Small vacuole common. Flat single faceting and

oblique fissuring rare.

Spondias dulcis Fruit 13-32 8-27 0.5-0.94Cylindrical, hemispherical,

ovate, spherical, subspherical

Small or large vacuole present. Lamellae and stellate, branching or

transverse fissuring common. Flat single faceting rare.

Tacca

leontopetaloides Stem tuber 4-20 3-17 0.5-0.67

Conical, cylindrical,

hemispherical, polygonal,

spherical

Flat and curved multiple and single faceting common. Longitudinal

fissuring rare. Simple and compound grains.

Xanthosoma

sagittifoliumCorm 4-13 3-12 0.5-0.6

Dome, polygonal, prismatic,

spherical

Flat and curved multiple and single faceting common. Longitudinal

fissuring rare. Simple and compound grains.

76

Multivariate statistical analysis of starch

Discriminant Function Analysis

Multivariate statistics in the form of Discriminant Function Analysis (DFA) was used to

discriminate between starch morphotypes observed at various taxonomic levels within the

comparative collection used for this study. DFA is a form of linear discrimination where

classification is based on the probabilities of an individual granule coming from groups with

particular means and variances (Torrence et al. 2004). This method is naturally comparative,

where data regarding modern plant taxa for which the taxonomy is known, provides the basis

for making predictions about unknown or unclassified individuals (Kovarovic et al. 2011),

making this statistical technique ideal for morphometric comparisons here. DFA utilises

predictor variables to determine the linear dimensions along which known groups are best

separated (Tabachnick and Lidell 2007). A new set of variables, known as discriminant

functions, are derived from building linear combinations of the original variables that maximise

between within-group variance. The number of discriminant functions is equal to the number of

groups minus one, and unless there are fewer predictor variables than groups, they only account

for the variance which best discriminates groups according to that model. Other possible options

such as logistical discrimination and nearest neighbour make fewer or no assumptions of the

data, but do not allow ready interpretation of the results in terms of individual variables

(Drennan 1996; Torrence et al. 2004), which is important for this study.

Data was collected during light microscopy and subsequent image analysis, whereby 18

attributes of 50 granules per sample were recorded, formed the dataset for the DFA. Each grain

had been rolled to view the 3D shape, but the metric variables including length and width were

measured off a photograph taken at a particular orientation. The Excel reference database was

therefore divided into two based on the orientation or view (eccentric/side-on or centric/end-on)

through which each grain had been recorded.

Table 5.4 Description of metric and binary variables used during Discriminant Function Analysis

View Metric

Centric Length 3D Shape- dome/hemispherical Small vacuole at hilum

Width 3D Shape- ellipsoidal/ovate Multiple facetting

Length of cross 3D Shape- reniform Flat facetting

Maximum distance between arms of cross3D Shape- angular (polyhedral, prismatic,

quadrangular, hexagonal)Curved/rounded facetting

Maximum distance between hilum and end 3D shape- pyriform/subspherical Fissuring at hilum

Maximum angle of the cross 3D Shape- spherical Concave-convex

Equitorial groove Large vacuole at hilum

Lamellae

Eccentric Length 3D Shape- conical/triangular Lamellae

Width 3D Shape-cylindrical Vacuole at hilum

Length of cross 3D Shape- dome/hemispherical Multiple facetting

Maximum distance between arms of cross 3D Shape- ellipsoidal/ovoidal Flat facetting

Maximum distance between hilum and end 3D Shape- reniform Curved/rounded facetting

Maximum angle of the cross3D Shape- angular (polyhedral, prismatic,

quadrangular, hexagonal)Fissuring at hilum

3D Shape- spherical Large vacuole

3D Shape- subspherical/subovoidal Tapered tip

Compressed Bent

Equitorial groove

Binary (presence or absence)

77

In order to be able to combine the data recorded from the range of ordinal, binary and

nominal variables, the nominal (or discontinuous) variables were converted into a series of

binary attributes. Thus 3D shape was converted into 14 binary variables, and the style of the

extinction cross was converted into three binary variables, each indicating the presence or

absence of that particular shape or style for that grain. After this data manipulation, a total of 34

variables were included in the initial DFA datasets and outputs.

PAST statistical software was used to conduct the multivariate statistical analyses. To

set a baseline for subsequent dataset comparison, both reference databases were initially

combined and entered into the PAST software together. The DFA was run using linear

discrimination and a confusion matrix was constructed based on the ‘classifier’ output from this

function. Essentially the DFA used the attributes included in the dataset as a ‘learning sample’

to predict the classification of each starch grain, and to establish how well each species could be

re-classified back into its own grouping. The confusion matrix gave an overall percentage of

correct re-classifications for the dataset, which when both orientations were combined was

48.3%.

This figure is statistically quite low, and emphasised the need to attempt the division of

the reference collection according to orientation, so that starch would only be compared to other

granules recorded in the same view. Due to the three dimensional nature of starch granules,

granules can be imaged and recorded from many different angles. In order to establish some

consistency within the datasets, the orientation was decided according to an acceptable range of

length to hilum position ratios for eccentric and centric views. As discussed earlier, this ratio

was calculated for each reference starch grain by dividing the maximum distance between the

hilum and the end of the grain, by the total length of the grain. A centric or end-on grain could

have a ratio of 0.5-0.6, and an eccentric or side-on grain could have a ratio of 0.61-1.0. The

database was thus divided according to these ratio ranges. Each reference database was entered

into the software separately, and outputs created in the same manner as the combined dataset.

Within the eccentric (side-on) view, the confusion matrix calculated that the total percentage of

correct re-classifications for that view was 53.6%. The centric dataset had a total percentage of

34%.

Clearly, the starch morphotypes in the eccentric dataset are more easily discriminated

from each other than those in the centric dataset. To increase the percentage of correct re-

classifications within the centric dataset and thus ensure that the archaeological starch can be

more confidently classified using DFA, some changes were made to the variables included in

the datasets. The ‘loadings’ which outline the role of each variable towards discrimination

within the DFA for each dataset were reviewed, and decisions were made to remove or re-

arrange some binary categories. The DFA was run with these new datasets, and higher

78

percentages of successful reclassification of species were achieved within both the eccentric and

centric views. The final DFA were run based on these revised datasets. Overall, the percentage

of starch granules within the eccentric dataset that were correctly reclassified to species was

72.98%. Understanding these values was vital towards characterizing starch morphology at

species level. Plots were then created that visually demonstrated the ability to discriminate

between each of the species in each of the datasets (see Figure 5.6and Figure 5.7). . These also

indicated the amount of discrimination due to each of the first two canonical variates, which

form the axis for the plot.

Table 5.5 Species included in centric and eccentric datasets for Tongan analysis

The reference collection up until this point had included a number of species that have never

been recorded in Tonga, such as Ipomoea polpha and Dioscorea rotundata but which had been

included to further our understanding of starch morphology at genus level within the larger

comparative collection. Ultimately the point of this analysis is to classify archaeological starch

with a high degree of confidence, and the inclusion of these species was making the

discrimination between species in both views more difficult due to similarities between their

recorded starch morphology. Species were therefore restricted to those found in Tonga in late

prehistory and also common contaminants. The final species list to be used in Part Two of this

thesis for the identification of archaeological starch included fourteen species within the

eccentric dataset, and fifteen species in the centric dataset, but again these were not necessarily

the same species within both datasets. The overall success rates of correct reclassifications

within these new datasets were 68.4% for eccentric, and 56.7% for centric.

Eccentric Centric

Amorphophallus paeoniifolius Alocasia macrorrhiza

Artocarpus altilis Amorphophallus paeoniifolius

Barringtonia asiatica Artocarpus altilis

Colocasia esculenta Barringtonia asiatica

Curcuma longa Colocasia esculenta

Dioscorea alata Cytrosperma merkusii

Dioscorea bulbifera Dioscorea esculenta

Dioscorea esculenta Inocarpus fagifer

Dioscorea nummularia Ipomoea batatas

Dioscorea pentaphylla Morinda citrifolia

Musa spp. Piper methysticum

Solanum tuberosum Pteridium sp.

Spondias dulcis Spondias dulcis

Tacca leontopetaloides Tacca leontopetaloides


79

Figure 5.6 Plot showing discrimination of species within centric dataset according to first two canonical

variates

Figure 5.7 Plot showing discrimination of 15 species within eccentric dataset according to first two canonical

variates

Classification matrices

When the confusion matrices for each of the datasets are analysed, it becomes apparent that

some species contain starch morphotypes that are more distinctive than others. In the centric

dataset only eight of the 20 specimens had over 60% of granules correctly re-assigned. The

80

specimen with the highest percentage of correct re-assignments were Colocasia esculenta with

77%, followed closely by Inocarpus fagifer with 76%, Morinda citrifolia and Spondias dulcis

with 74%, Amorphophallus paeoniifolius with 72%, and Pteridium sp. with 71%. The

specimens that were the least able to be differentiated within the eccentric view (i.e. under 30%)

include Barringtonia asiatica seed (11%), Xanthosoma sagittifolium (24%), Artocarpus

heterophyllus (25%), and Artocarpus altilis seed (26%). As discussed previously, starch from

several species was more easily distinguished within the eccentric view, and 12 of the 19

specimens included in this dataset had over 60% of granules correctly re-assigned. Of these, two

specimens, C. esculenta and S. dulcis, had all recorded starch re-assigned to the original

specimens. Only slightly less successful than these was Curcuma longa with 98% and

Dioscorea rotundata with 94%. The specimens with the lowest percentages of correct re-

assignment within the eccentric dataset, and thus the least able to be differentiated using

attributes within the dataset are Dioscorea esculenta (24%) and Ipomoea polpha (30%).

Automated classification of granules of unknown origin

The multivariate statistical analysis fulfilled several goals within the morphological analysis of

the comparative collection. Firstly, the analysis emphasised those attributes that were most

useful towards discriminating between the starch morphotypes found in specimens included in

the comparative collection. Of the 21 variables compared within the centric dataset, and the 25

variables in the eccentric dataset, the metric variables consistently had the highest loadings. This

suggests that these attributes are an important source of morphological variation. Of these,

starch ‘length’ had the highest loading in the centric dataset, while ‘length of cross’ and

‘maximum distance between the arms of the cross’ had higher loadings within the first two

canonical variates in the eccentric dataset. Surprisingly all other attributes, such as categories of

three-dimensional shapes, contributed minimally to the differentiation of species within the

comparative collection which implies that these should not be heavily relied on for

identification of unknown granules. The automated classification of unknown granules using

DFA is a useful first step, but should be expressed with varying levels of confidence and

visually cross-checked before final confirmation of taxonomic identifications, as will be

explored in Part Two of this thesis.

81

Figure 5.8 Classification matrix for the overall centric dataset, showing highest discrimination of Colocasia

esculenta, Inocarpus fagifer, Morinda citrifolia and Spondias dulcis (species listed vertically in the first column

are the original species, and those listed horizontally in the top row are the species to which DFA classified

granules)

Figure 5.9 Classification matrix for the overall eccentric dataset, showing highest discrimination of Colocasia

esculenta, Curcuma longa, and Dioscorea pentaphylla (species listed vertically in the first column are the

original species, and those listed horizontally in the top row are the species to which DFA classified granules)

82

Morphology of vegetative storage parenchyma

Morphological analysis of fresh samples

Hather (1991, 2000) discriminates between the vegetative storage parenchyma that is found in

roots and tubers, and all other parenchymatous organs such as fruits, seeds, and nuts. He makes

this distinction because the function of these organs is to store reserve starch and carbohydrates

during photosynthesis for plants, and thus these organs share many similar morphological traits.

It is this storage function, and subsequent calorific and nutritional value, that led to the

development of many prehistoric subsistence strategies based upon the collection or cultivation

of these starchy organs (Barton and Paz 2007; Denham 2007b; Golson 2007; Holden, Hather

and Watson 1995).

In the comparative collection of modern parenchyma developed for this study, a number

of fruits and seeds were also included. The justification for these inclusions was that these

organs also often produce starch and other vitamins and minerals, and have been recorded in the

ethnographic record for Tonga (Beaglehole and Beaglehole 1941; Gifford 1929; Whistler 2009)

to supplement diets either on a regular basis or during times of famine. Fruits such as breadfruit

(Artocarpus altilis), the tropical almond (Inocarpus fagifer), and bananas (Musa spp.) were

grown bordering plantations of yams (Dioscorea spp.), aroids (Colocasia esculenta, Alocasia

macrorrhiza, Cyrtosperma merkusii), sweet potato (Ipomoea batatas), kava (Piper

methysticum) and arrowroot (Tacca leontopetaloides). Under the premise that these crops were

being processed and cooked in the same areas as the roots and tubers, it is possible that some

macro-remains of these organs may end up charred in hearths and were preserved in

archaeological contexts. This has been documented elsewhere in Polynesia by the recent find of

breadfruit in Tahiti (Kahn and Ragone 2013).

The organisation of tissues within fruits does differ from that of stem and root-derived

organs, and therefore they were described separately. The basic cell morphology and types of

boundary, ground and some vascular tissues were recorded for each sample of non-vegetative

storage parenchyma. Some similarities emerged such as the nature of the ground tissues and the

arrangement of vascular bundles where these were present within the organ. Most of the fruits

included in this study are Dicotyledons or Eudicotyledons, and thus have different anatomical

features from Monocotyledons which form the bulk of the species within the comparative

collection. This data thus provided a means of comparison with the stem and root-derived

organs. Here, fresh samples will be analysed using univariate and multivariate statistical

analyses to study parenchyma morphology, with a small study upon the changes that occur

during charring. These studies summarise the descriptions provided in Appendix A.

83

Ground tissue morphology

Some of the distinguishing features of parenchyma ground tissue are best described through

comparison of these tissues with hardwood. Some differences to wood charcoal include

consistent cell shapes that are usually rounded or angular; the presence of distinctive vascular

bundles or tissues, and there are usually very few rays dividing these tissues. When comparing

vegetative and non-vegetative storage parenchyma from within roots, tubers, fruits and seeds

with each other these morphological features need to be teased apart to allow identification of

charred material where possible.

As described above, 40 cells from each specimen were recorded to assess the

morphology of parenchymatous ground tissues within roots, tubers, fruits and seeds. The length

and width of each cell was recorded, along with cell shape (rounded, angular or rounded-

irregular), and cell dimensions (isodiametric or elongated). On top of these attributes of the

individual cells, some overall descriptions were made about the ground tissue. These included

the overall presence or absence of inter-cellular spaces, and the variety of cell contents that had

been preserved in the histological thin sections.

Most species contained ground tissue that were consistently either rounded (60%,

n=26), rounded-irregular (12%, n=5), or angular (21%, n=9); however a small percentage (7%,

n=3) had both rounded and angular cell shapes within the same specimen. These included

Artocarpus altilis, Colocasia esculenta, and Dioscorea alata, and interestingly these species do

not share any phenotypical or genotypical traits with one another aside from the fact that all

three specimens are types of starchy organs. These specimens represent a range of different

storage organs including a fruit (A. altilis), a corm (C. esculenta) and a tuber (D. alata). The

yams (Dioscoreaceae) are traditionally classified as root tubers; however the anatomy of these

organs is much closer to stem-derived tissue than true roots. Onwueme (1978) argues that the

yam tuber is “probably neither a root nor a stem structure. Rather it is a structure that

originates from the hypocotyls- the transition zone between the stem and the root”. With this in

mind, the attributes for describing stem anatomy have been used here for yams rather than root

anatomy, especially with regard to the arrangement of vascular tissues and overall tissue

organisation.

The ground tissues of the remaining yams (Dioscorea bulbifera, Dioscorea esculenta,

and Dioscorea nummularia) and the Polynesian arrowroot (Tacca leontopetaloides), which also

belongs to the Dioscoreaceae family, are all rounded in shape. Similarly, the remaining aroids

(Alocasia macrorrhiza, Cyrtosperma merkusii, and Xanthosoma sagittifolium) have rounded

cells within the ground tissues. Other starchy crops such as the bananas (Musa spp.), kava (P.

methysticum) and a type of ginger (Zingiberaceae sp.) contain more irregularly rounded cells

within the ground tissue. The majority of the Pteriodophytes or ferns have more angular shaped

cells, including Asplenium sp., Pteridium sp., and Todea sp. Similarly many of the fruits such as

84

Barringtonia asiatica, Barringtonia racemosa, Ficus tinctorius, Spondias dulcis, and Syzygium

malaccense have angular ground tissue cells.

Table 5.6 Ground tissue cell shapes of taxa in reference collection

The majority of specimens included in this analysis had ground tissue parenchyma cells

that were a mixture of elongated (greater in length than width) and broadly isodiametric

(roughly even in length and width) in dimension. These specimens with mixed dimensions

totalled 37 out of the full 43 specimens, equating to 86%. The remaining 14% (n=6) of

specimens had consistently broadly isodiametric cell dimensions. These included Barringtonia

asiatica fruit, Barringtonia racemosa seed, Dioscorea nummularia, Ficus copiosa, Saccharum

officinarum, and Xanthosoma sagittifolium, and represent a range of different plant families and

organ types. There does not appear to be any patterning that may suggest why this particular

range of specimens has solely isodiametric cells within the recorded random sample of ground

tissue recorded.

Table 5.7 Ground tissue cell dimensions of taxa in the reference collection

Rounded- irregular Angular

Artocarpus altilis seed Epipremnum pinnatum Musa sp. 1 Asplenium sp.

Alocasia macrorrhiza Ficus copiosa Musa sp. 2 Barringtonia asiatica fruit

Angiopteris sp. Inocarpus fagifer Piper methysticum Barringtonia racemosa seed

Asplenium sp. Morinda citrifolia Solanum tuberosum Ficus tinctorius

Araceae sp. Pangium edule Zingiberaceae sp. Ipomoea batatas

Barringtonia asiatica

seedPueraria lobata Pteridium sp.

Barringtonia racemosa

fruitSaccharum officinarum Spondias dulcis

Cordyline fruiticosa Pandanus tectorius Mixed Syzygium malaccense

Cyrtosperma merkusiiTabernaemontana

aurantiacaArtocarpus altilis fruit Todea sp.

Dioscorea bulbifera Tacca leontopetaloides Colocasia esculenta

Dioscorea esculenta Xanthosoma sagittifolium Dioscorea alata

Dioscorea nummularia Zingiberaceae sp.

Rounded

Isodiametric

Barringtonia asiatica fruit Artocarpus altilis seed Ipomoea batatas

Barringtonia racemosa seed Artocarpus altilis fruit Inocarpus fagifer

Dioscorea nummularia Alocasia macrorrhiza Morinda citrifolia

Ficus copiosa Angiopteris sp. Musa sp. 1

Saccharum officinarum Asplenium sp. Musa sp. 2

Xanthosoma sagittifolium Araceae sp. Pangium edule

Barringtonia asiatica seed Pueraria lobata

Barringtonia racemosa fruit Piper methysticum

Colocasia esculenta Pandanus tectorius

Cordyline fruiticosa Pteridium sp.

Cyrtosperma merkusii Spondias dulcis

Dioscorea alata Syzygium malaccense

Dioscorea bulbifera Solanum tuberosum

Dioscorea esculenta Tabernaemontana aurantiaca

Dioscorea nummularia Tacca leontopetaloides

Epipremnum pinnatum Todea sp.

Ficus tinctorius Zingiberaceae sp.

Mixed

85

The statistical analysis of cell lengths and widths points to a large degree of overlap in

these particular attributes of ground tissue morphology. Box plots were created using the PAST

statistical software to visually display the range of cell lengths and widths for each of the

specimens included in the modern comparative collection. Outliers were indicated within the

ranges of almost every species and organ, indicating that the random sample of 40 cells

recorded in this study may not fully represent the degree of variation within the ground tissue of

each specimen.

Despite this, the box plots demonstrate that most cell lengths within the comparative

collection fall into a range larger than 40µm and smaller than 160µm. A number of species have

cell lengths that could exceed 160µm, including Alocasia macrorrhiza, Angiopteris sp.,

Asplenium sp., Dioscorea alata, Dioscorea esculenta, Dioscorea nummularia, Ficus copiosa,

Ficus tinctorius, Ipomoea batatas, Musa sp. 2, Spondias dulcis, Solanum tuberosum, Tacca

leontopetaloides and Todea sp. The overall ranges of many of these species are very similar,

and therefore the diagnostic value of this attribute of ground tissue morphology is reduced. To

narrow this down further it may be more useful to consider the smaller number of species that

have cell lengths that can exceed 240µm. These include Angiopteris sp., Asplenium sp., D.

esculenta, D. nummularia and S. dulcis. The largest cells recorded within the comparative

collection are in the ground tissues of Asplenium sp. and D. esculenta, which both can exceed

320µm in length. On the smaller end of the spectrum, some specimens have cell lengths that can

range below 40µm such as the fruit of Artocarpus altilis and the stem of Saccharum

officinarum. The two samples of the fruit phalange of Pandanus tectorius, and the root tuber of

D. nummularia indicate that there can be some intra-species diversity in cell lengths, and

therefore this attribute of ground tissue morphology should be considered mostly undiagnostic

on its own.

All taxa within the reference collection have cell widths within the ground tissues that

can range between 30-120µm. However, just over a third of the specimens have cell width

ranges where the minimum widths are smaller than 30µm (37%, n=16). These include A. altilis

fruit, Araceae sp., B. asiatica fruit, B. racemosa seed, C. merkusii, F. copiosa, F. tinctorius, I.

fagifer, M. citrifolia, Musa sp. 1., Pangium edule, S. dulcis, Syzygium malaccense, S.

officinarum, and both Zingiber spp. The specimens that have ground tissue cell widths that

range above 120µm (35%, n=15) include Alocasia macrorrhiza, Angiopteris sp., Asplenium sp.,

D. alata, D. bulbifera, D. esculenta, D. nummularia, F. tinctorius, Musa sp.2, S. dulcis, S.

malaccense, S. tuberosum, T. leontopetaloides and Todea sp.. The largest cell widths by quite a

significant margin are those of D. esculenta, which range up to 230µm and so is a diagnostic

attribute of parenchyma from this species.

86

Considering the degree of overlap between specimens in the univariate analysis of each

of the recorded metric attributes, it was prudent to carry out a multivariate statistical study that

could assess the relationships between sets of attributes in the modern comparative collection. A

dataset was created in the PAST program that included the data of four attributes: cell lengths,

widths, shapes and dimension of 40 recorded ground tissue cells from each specimen. Cell

shape and dimensions were turned into nominal variables, with a number from 1-3 representing

each shape (rounded, rounded-irregular or angular) and 1-2 representing each type of dimension

(isodiametric or elongate).

DFA of the parenchyma attributes was carried out in the same way that the starch

samples were analysed. A confusion matrix was created, with a total of only 21.8% of the

recorded cells being correctly re-classified back into the original species. This figure is

statistically very low, indicating that the majority of modern specimens could not be easily

disciminated from one another based on these four attributes. Despite this, a small number of

specimens were able to be separated from the remaining groupings reasonably well. The most

easily discriminated was Musa sp. 1,which had a total of 78% correct reclassifications into

original species. Closely following this was Dioscorea esculenta with 73%. Several species

including the seed of Barringtonia racemosa (60%), and the fruit of Ficus copiosa (58%) had

over half of all the cells correctly reclassified. The outputs of the DFA complemented the

outcome of the univariate analysis, suggesting that there is substantial overlap within the

morphology of ground tissues of many of the specimens in the modern comparative collection.

Clearly some species will be more easily identified during the sorting of archaeological samples

based on the morphology of ground tissue, such as those that have cells larger than 160µm or

smaller than 40µm, those that have mixed cell shapes or consistently isodiametric cell

dimensions. The majority of cells do not fall within these ranges, and so other non-metric

attributes need to also be considered.

87

Figure 5.10 Box plot of parenchyma cell lengths of taxa in the reference collection

88

Figure 5.11 Box plot of parenchyma cell widths of taxa in the reference collection

89

Figure 5.12 Plot showing classification of parenchyma within reference collection using DFA

Other features of the ground tissue can include the presence of inter-cellular spaces,

sclerenchyma, collenchyma, fibre bundles, duct cavities and cell contents. These can also be

used to differentiate some species from one another. For example, both Musa sp. 1 and Musa sp

2. have duct cavities three to four cells long throughout the ground tissue that separate rows of

parenchymatous cells. These species also contain fibre bundles which are also common

throughout Zingiber spp., Asplenium sp., Cordyline fruticosa, Epipremnum pinnatum, and

Pandanus tectorius. Regions of sclerenchyma can be observed within the pith of the fruit of

Artocarpus altilis, Pangium edule, and Piper methysticum; while collenchmya forms the pith of

Angiopteris sp. Inter-cellular spaces are present in most ground tissues; however it is absent in

Dioscorea bulbifera, Pteridium sp., Spondias dulcis, Saccharum officinarum, and Solanum

tuberosum. Cell contents can include also raphides, starch granules, druses and other types of

crystals. Raphides are most commonly seen in aroids, but are also noticeable in the ground

tissue of Tacca leontopetaloides.

Vascular tissue morphology

The overall tissue organisation within the parenchyma of the modern specimens varies between

the root and stem-derived organs, and the fruits and seeds, alongside the typical anatomical

differences between Monocots and Dicots. The vascular tissues within these types of organs

therefore also vary. Bundles of vascular tissues are present in stem-derived organs, where the

phloem and xylem are either encircling or abutting one another. These bundles can be organised

within the organ in one of three ways: 1) Dictyostele, where the bundle is formed as a chamber

surrounding the pith and can be broken into segments; 2) Eustele, where bundles are arranged

concentrically as either primary or secondary tissues radiating from the pith; or 3) Atactostele,

where the bundles are organised seemingly haphazardly within the ground tissue of the organ.

90

The arrangement of the xylem and the phloem within the bundles can also be categorised into

morphological types. These include:

Amphivasal concentric— xylem completely encircles the phloem;

Amphivasal open ends— xylem almost completely encircles phloem apart from each

end of the bundle;

Amphivasal u-shaped-—xylem partially surrounds the phloem in a u-shape formation;

Amphicribal concentric— phloem completely encircles the xylem;

Amphicribal open ends— phloem almost completely encircles xylem apart from each

end of the bundle;

Amphicribal u-shaped— phloem partially surrounds the xylem in a u-shape formation

Open collateral- bundles of phloem and xylem abut one another with a region of

cambium between the two types of tissue;

Closed collateral- bundles of phloem and xylem abut one another with no region of

cambium between the two types of tissue;

Bicollateral—bundles of phloem and xylem abut one another with a region of cambium

between the two types of tissue, and another additional bundle of phloem or xylem is

present below this arrangement.

Figure 5.13 Description of vascular bundle arrangements within vegetative parenchyma (from Hather 2000)

When considering the stem-derived organs such as corms, rhizomes and stem tubers, it

is clear that the majority of vascular tissues are organised within an atactotstele morphology

(58%, n=11). Much smaller numbers are organised within a eustele (16%, n=3), or dictyostele

arrangement (26%, n=5). Those specimens that contain an atactostele arrangement of vascular

tissues tend to be corms and stem tubers of Monocots, while the dictyostele arrangement is most

91

common in the Pteriodophytes or fern rhizomes, and the eustele arrangement is commonly seen

in Dicots. When the arrangements of vascular tissues within these bundles are broken down into

their respective categories, further patterning becomes apparent. Some specimens did not have

visible or clear vascular tissues and so were not included in the below table (see Table 5.8).

All of the aroids (Araceae) assessed within this study have vascular bundles within an

atactostele pattern of stele organisation (as these are Monocots), and the vascular tissues are of

an amphivasal arrangement where the phloem is surrounded by the xylem. Colocasia esculenta

is the only aroid to contain two different types of amphivasal bundling, having both amphivasal

concentric and u-shaped. Both Alocasia macrorrhiza and Cyrtosperma merkusii have

amphivasal open-ended bundles, while Xanthosoma sagittifolium has bundles of amphivasal

concentric arrangement. Another family belonging to the Monocots are the yams

(Dioscoreaceae) and therefore have vascular bundles within an atactostele organisation;

however these tissues differ from those belonging to the aroids as they are all of collateral

bundling arrangement. Dioscorea alata and both samples of Dioscorea nummularia have

bundles of open collateral arrangement with a region of cambium between the vascular tissues,

while Dioscorea esculenta has closed collateral bundles without the layer of cambium. The only

species from Dioscoreaceae to have a bicollateral arrangement is Tacca leontopetaloides, but

outside this family Solanum tuberosum and Saccharum officinarum also contain bundles of this

arrangement. The two specimens belonging to the Zingiberaceae family both have vascular

tissues of amphicribal concentric arrangement where the xylem is surrounded the phloem.

Table 5.8 Vascular tissue arrangements of taxa in reference collection

Collateral Amphivasal Amphicribal

Dioscorea alata Alocasia macrorrhiza Zingiberaceae sp.

Dioscorea bulbifera Colocasia esculenta

Dioscorea esculenta Cordyline fruticosa Stem- Dictyostele

Dioscorea nummularia Cyrtosperma merkusii Angiopteris sp.

Tacca leontopetaloides Xanthosoma sagittifolium Asplenium sp.

Solanum tuberosum Epipremnum pinnatum Pteridium sp.

Saccharum officinarum Todea sp.

Collateral Amphicribal Unknown

Ficus copiosa Artocarpus altilis Pangium edule

Ficus copiosa Morinda citrifolia

Amphivasal Inocarpus fagifer Ficus tinctorius

Barringtonia asiatica Musa sp. 1

Barringtonia racemosa Musa sp. 2 Root

Pandanus tectorius Spondias dulcis Ipomoea batatas

Syzygium malaccense Pueraria lobata

Tabernaemontana aurantiaca Piper methysticum

Stem- Atactostele

Fruit

92

The arrangement of vascular tissues within the fruits can vary significantly between

samples. Where vascular bundles are present, these are not organised within an atactostele,

eustele or dictyostele arrangements, but depend on other anatomical features of the organs. The

arrangement of the tissues in the bundles is described, but not the overall organisation within the

fruit as these do not fit any of the morphological categories used previously. The main purpose

of including these samples is the description of basic cell and vascular morphology, in order to

explore some differences between these organs and vegetative storage parenchyma. Almost half

of the fruit specimens included within the comparative collection have vascular bundles of

amphicribal arrangement (47%, n=8). Within these are a number of specimens with amphicribal

concentric bundles including both Musa spp. and Tabernaemontana aurantiaca, and one

example of a specimen with amphicribal u-shaped in Artocarpus altilis. A different version of

amphicribal arrangement is seen in Syzygium malaccense where a stellate pattern of the xylem is

present. Both fruits of Barringtonia spp. and Pandanus tectorius contained amphivasal

concentric bundles. Finally, there is one specimen that contains vascular tissues with more than

one type of arrangement. Ficus copiosa has amphicribal concentric and u-shaped alongside

closed collateral bundles.

The true roots have vascular tissues that are regions of parenchyma within the stele and

cortex of the organs, and there is very little variation between Monocotyledons and

Dicotyledons. In primary root tissues, the cortex is often wide and the stele is central with very

little pith (Hather 2000:61). A region of endodermis and pericycle separate the cortex from the

stele, within which are alternate regions of phloem, xylem and cambium. The number of regions

of vascular tissues within the stele can be as few as two (diarch), three (triarch), four (tetrarch),

five (pentarch) or many (polyarch). Secondary root tissues have a different organisation of the

vascular tissues, where the cortex is shed and the stele expands to replace the ground tissue by

expanding centripetally to produce xylem and centrifugally to produce phloem and parenchyma.

The centre of the organ is therefore composed of xylem and the outer region is composed of

phloem and pericyclic parenchyma with a cambium separating these, and a periderm on the

external surface.

The root samples within the modern comparative collection have some variation within

the vascular tissues. The specimen of Pueraria lobata or Kudzu is a primary root tissue and has

a polyarch xylem organisation within the stele with many vessels. Kava (Piper methysticum)

root is a secondary structure that has many arms of fibre and xylem radiating from the pith, and

bundles of phloem in between these. Sweet potato or Ipomoea batatas has a typical vesicular

xylem that shows signs of anomalous tertiary growth next to vessels, surrounded by

parenchymatous phloem outside the cambium.

93

Having considered the nature of bundle arrangements, it became clear that a level of

overlap within the morphology of these vascular tissues exists. A univariate study of bundle

lengths was carried out to assess the potential role of this attribute in distinguishing between

species within the comparative collection. As demonstrated in the box and whisker plot (below,

see Figure 5.14), there is again significant overlap in the measured specimens, with the majority

of specimens falling into the 150-600µm range. However a number of species are smaller or

larger than this. Rather than comparing this attribute across the whole comparative collection, it

is more useful to consider each of the typologies for bundling morphology. When the range of

specimens containing each type of bundling arrangement is compared with one another, bundle

length becomes an important attribute in differentiating between them.

Within the atactostele collateral typology Dioscorea alata has statistically larger

bundles than the other five specimens. Where the other specimens have bundle lengths that

range between approximately 150-550µm, D. alata has a range from 250-890µm. On the

opposite end of the spectrum, Saccharum officinarum is the only specimen with this bundle

typology that also has bundles smaller than 150µm. It is harder to differentiate between the

specimens with atactostele amphivasal arrangement. There is overlap between the bundle length

ranges of all specimens apart from Xanthosoma sagittifolium which has the bundles that can be

smaller than 150µm, with a minimum size of 100µm. Both Zingiber spp. within the atactostele

amphicribal bundle typology have statistically different bundle length ranges. Zingiber sp.

(BG957) has a range from 300-450µm, while Zingiber sp. (EU008) has a range smaller than this

between 160-300µm.

The fruit specimens can also be differentiated based on the ranges of bundle lengths

within the bundle typologies. The specimens with amphivasal bundles have some overlap

between 210-750µm, but the box plot shows that there some specimens with smaller bundles

that can be differentiated from the others. Barringtonia asiatica has very little overlap with any

other species, with a range of 85-160µm which represents the smallest bundles in this

typological category. Slightly larger than this is Barringtonia racemosa, which has a range of

150-410µm and therefore can be identified based on bundle lengths from 160-210µm. The

remaining Pandanus spp. specimens within this bundle typology cannot be differentiated based

on bundle length. Amphicribal specimens have a much larger amount of overlap between the

bundle length ranges of specimens. At the smaller end of the spectrum, bundles smaller than

170µm can belong to either Artocarpus altilis or Musa sp. 1. Bundles larger than 620µm can

only belong to Musa sp. 2 according to these statistical ranges.

94

Figure 5.14 Box plot showing vascular bundle lengths within reference collection according to tissue

arrangement

Combining these two morphological attributes allows more accurate differentiation of

parenchyma in the comparative collection. For those specimens that had similar bundle lengths

to others with the same bundle typology, a multivariate approach was needed to further test

whether classification of unidentified samples is possible based on bundle morphology. This

multivariate statistical approach included an additional variable- bundle width- within a PAST

dataset and used the same DFA approach as that used to explore starch and parenchyma cell

morphology. First, individual datasets were created for the atactostele (stem-derived roots and

tubers) and the fruits so that these could be analysed separately. Two ordinal variables were

included- bundle length and width, and one nominal- bundle morphology.

The specimens within the atactostele bundle typology dataset had an overall correct

reclassification rate of 74.7%. A number of specimens had all five recorded bundles correctly

re-classified into the same specimen. These included Araceae (EU2012-08), Cordyline

fruticosa, Dioscorea esculenta, Saccharum officinarum, Tacca leontopetaloides, Xanthosoma

sagittifolium and Zingiber sp. Several others only had one bundle incorrectly classified, such as

Dioscorea nummularia, Epipremnum pinnatum and another Zingiber sp. Alocasia macrorrhiza,

Cyrtosperma merkusii, Dioscorea alata and X. sagittifolium all had 60% (n=3) of the five

bundles reclassified correctly, while the remaining two specimens had less than half of the

bundles correctly assigned and were not easily discriminated from the other specimens based on

95

these three attributes. The overall loadings from this analysis indicated that bundle length was

consistently the most diagnostic variable included in the dataset.

The confusion matrix constructed indicated that the specimens in fruit bundle

typologies were less able to be distinguished from one another based on bundle length, width

and arrangement, than the atactostele specimens. Overall, 70.2% of the bundles included in this

dataset were correctly reclassified to specimen of origin. As with the atactostele dataset, there

were a number of specimens that had all of the included bundles correctly re-assigned. These

specimens included Artocarpus altilis, Barringtonia asiatica, Musa sp.1, and Syzygium

malaccense. Several others had over half of the bundles correctly reclassified to original

species, including Musa sp. 2 and Pandanus tectorius with 80% correct. The outputs of using

DFA on this dataset indicate that these particular specimens are able to be differentiated from

the others within the dataset based on the three attributes for bundle morphology used here.

Bundle length was again shown to be the most diagnostic variable within the loadings for the

fruit dataset.

Consideration of the diagnostic value of these attributes within the atactostele and fruit

datasets separately is useful for discrimination when the arrangement of vascular bundles is

known; however when attempting to identify a fragment of archaeological parenchyma, the

overall arrangement is not always visible within that particular fragment. Considering this, the

value of bundle morphology in the dataset as a whole was assessed. The atactostele and fruit

datasets were combined and the DFA run again with the same three variables of bundle length,

width and arrangement. Overall, the percentage of correct re-classifications within this dataset

was 62.3%. Eight specimens had all five recorded bundles correctly re-assigned, including

Artocarpus altilis, Araceae sp., Barringtonia asiatica, Dioscorea esculenta, Musa sp. Syzygium

malaccense, Saccharum officinarum, and Tacca leontopetaloides. These were all specimens that

had 100% correct re-classifications within the separated datasets and so are easier to classify

when compared to the whole range of specimens with vascular bundling in the comparative

collection. Another five specimens had four out of the five bundles re-classified to the correct

specimen of origin. These included Cordyline fruticosa, Epipremnum pinnatum, Musa sp.2,

Pandanus tectorius and Zingiber sp. These and a further five specimens, Alocasia macrorrhiza,

Cyrtosperma merkusii, Xanthosoma sagittifolium, Zingiber sp. had over half of the included

vascular bundles allocated to the original specimen and could therefore be identified based on

these three attributes with a moderate level of confidence. The remaining seven species could

not be confidently differentiated from the other specimens included in the analysis. These

specimens include Barringtonia racemosa, Colocasia esculenta, Dioscorea alata, Dioscorea

nummularia, Ficus copiosa, Pandanus tectorius and Tabernaemontana aurantiaca.

96

Table 5.9 Summary of parenchyma morphology within reference collection

Species Organ Boundary tissue description

Cell

length

range

(µm)

Cell

width

range

(µm)

Ground tissue description

Vascular

bundle length

range (µm)

Vascular bundle

width range (µm)Vascular tissue description

Artocarpus altilis Fruit

Outer epidermis of 2-3 layers of thickened

radially organised rounded and isodiametric

cells.

40-60 30-40

Rounded and isodiametric, angular and

elongate, rounded and elongate. Inter-

cellular spaces.

100-600 70-280 Atactostele and amphicribal u-shaped.

Artocarpus altilis Seed

Outer thin epidermis composed of 1 layer of


cells with thickened cell walls.

60-80 50-65

Mostly rounded and isodiametric, some

elongate. Inter-cellular spaces. Pith of

sclerenchyma.

80-900 75-360 Atactostele and amphicribal concentric.

Alocasia macrorrhiza Corm

A layer of thick periderm. Cortex of c.20 rows

of angular and elongated cells with very thin

cell walls. Vascular cambium of 2 rows of

similar cells with thicker walls.

80-130 70-100Mostly rounded and isodiametric, some

elongate. Inter-cellular spaces. 300-560 200-450 Atactostele and amphicribal open-ended.

Angiopteris sp. Rhizome

Outer epidermis of 3 layers of radially

organised rounded and elongated cells with

thickened cell walls.

100-150 85-100Rounded and elongate, some

isodiametric. Inter-cellular spaces.Unmeasured Unmeasured Dictyostele.

Asplenium sp. 1 Rhizome

Outer epidermis of one layers of radially

organised angular and isodiametric cells with

thickened cell walls. Below this a broad region

of 7-8 rows of fibres.

55-80 45-70Rounded and isodiametric, some

elongate. Inter-cellular spaces.770-960 390-810 Dictyostele and amphicribal concentric.

Asplenium sp. 2 Rhizome

Outer epidermis of one layers of radially

organised angular and isodiametric cells with

thickened cell walls. Below this a broad region

of 7-8 rows of fibres.

115-175 90-130Angular and isodiametric or elongate.

Inter-cellular spaces.160-950 110-570 Dictyostele and amphicribal concentric.

Barringtonia asiatica Fruit

Outer epidermis of one layer of very small


cells with a thick outer cell wall. Below this a

row of palisade mesophyll cells.

55-105 40-75Angular and isodiametric. Inter-cellular

spaces.85-160 85-150 Eustele and amphivasal concentric.

Barringtonia asiatica Seed

Outer epidermis of one layers of very small


cells with thick cell walls. Two rows of

vascular cambium separates the cortex and

pith.


elongate. Inter-cellular spacesNot observed Not observed Not observed

Barringtonia racemosa Fruit

Thin epidermis of a single layer of angular

and elongated cells with thick cell walls.

Another possible 10 rows of rounded and

elongated cortical parenchyma below the

epidermis.


elongate. Inter-cellular spaces.150-400 110-300 Eustele and amphivasal concentric.

Barringtonia racemosa Seed

Outer epidermis of one layers of rounded and

isodiametric cells with a thick outer cell wall.

Two rows of very small angular and elongated

cells make up the vascular cambium which

separates the cortex and pith.

60-85 50-70Angular and isodiametric. Inter-cellular

spaces.Not observed Not observed Not observed

Colocasia esculenta Corm

Outer thickened epidermis composed of 3

layers. 20 rows of cortical parenchyma

angular and elongated with thin cell walls.

Two rows of angular and isodiametric cells

with thick cell walls make up the vascular

cambium.

70-100 50-75Rounded or angular and isodiametric or

elongate. Inter-cellular spaces.230-580 160-400

Atactostele and amphivasal concentric or

u-shaped.

97


Cell

length

range

(µm)

Cell

width

range

(µm)


Vascular

bundle length

range (µm)

Vascular bundle


Cordyline fruticosa Root

Outer thickened epidermis and below this a

region of cortical parenchyma which is

rounded and isodiametric with thin cell walls.

55-75 40-55Angular and isodiametric or elongate.

Inter-cellular spaces.200-300 100-200

Atactostele and amphivasal concentric.

Fibre sheath.

Cyrtosperma merkusii Corm Not observed 40-80 30-50Rounded and elongate, some

isodiametric. Inter-cellular spaces.300-500 200-300µm Atactostele and amphivasal open-ended.

Dioscorea alata Root tuberEpidermis consisting of 4 layers of angular

and elongated cells with thick cell walls.80-110 50-75

Rounded and elongate or isodiametric,

some irregularly rounded and elongate.

Inter-cellular spaces.

230-880 85-340 Atactostele and closed collateral.

Dioscorea bulbiferaAerial

bulbil

One layer of thickened epidermis. A region of

vascular cambium of five rows of angular and

elongated cells.


elongate.Not observed Not observed Not observed

Dioscorea esculenta Root tuberEpidermal region of 3 layers of angular and

elongated cells.150-235 100-160

Rounded and isodiametric, some

elongate. Some inter-cellular spaces.150-380 80-240 Atactostele and closed collateral.

Dioscorea nummularia Root tuberThickened epidermis outside 5 rows of

angular and elongated cortical parenchyma.75-115 60-100

Rounded and isodiametric, some

elongate. Inter-cellular spaces.155-435 100-250 Atactostele and open or closed collateral.

Epipremnum pinnatum Corm

Thickened single-layer periderm above 5 rows

of angular and elongated primary cortical

parenchyma cells with thin cell walls. Another

five rows of similarly shaped cells compose a

region of secondary cortex. A row of vascular

cambium of one layer of rounded and

elongated cells.


elongate. Inter-cellular spaces.220-375 180-300 Eustele and amphivasal u-shaped.

Ficus copiosa Fruit Not observed 40-60 30-45Rounded and isodiametric. Inter-

cellular spaces.70-380 60-150

Eustele and closed collateral or

amphicribal u-shaped or concentric.

Ficus tinctorius Fruit Not observed 55-90 25-70Angular and isodiametric or elongate.

Inter-cellular spaces.Not observed Not observed Not observed

Ipomoea batatas Root tuber

A region of periderm of about 4 rows of

radially-orientated angular and isodiametric

cells with thin cell walls.

80-115 60-90

Region of parenchymous secondary

phloem outside the cambium. Angular

and isodiametric, some elongate.

Not applicable Not applicable

The parenchyma within the secondary

xylem same as phloem, regions of

anomalous tertiary growth adjacent to

individual vessels. Divide both

periclinally and tangentially to produce

concentric radiating rings of tertiary

xylem.

Inocarpus fagifer Seed

A layer of endocarp consists of a row of

angular and isodiametric cells with very thick

cell walls.


elongate.Unmeasured Unmeasured Atactostele and amphicribal u-shaped.

Morinda citrifolia Fruit Not observed 40-60 30-50Rounded and isodiametric, some

elongate.Not applicable Not applicable Not applicable

Musa sp. 1 Fruit Not observed 60-90 50-70

Irregularly rounded and isodiametric,

some elongate. Inter-cellular spaces and

duct cavities.

80-115 70-100 Eustele and amphicribal concentric.

Musa sp. 2 Fruit Not observed 73-215 46-170

Irregularly rounded and isodiametric,

some elongate. Inter-cellular spaces,

duct cavities and fibre bundles.

220-680 180-370 Eustele and amphicribal concentric.

98


Cell

length

range

(µm)

Cell

width

range

(µm)


Vascular

bundle length

range (µm)

Vascular bundle


Pandanus tectorius Fruit

phalange

Epidermis of one row of thickened, rounded

and isodiametric cells. Below is one row of

similarly rounded and isodiametric cells with

slightly thinner cell walls.



Atactostele and amphicribal concentric.

Concentrated near pith. Fibre sheath.

Pangium edule Fruit

Periderm made up of around 6 rows of

angular and elongated cells. Below is a region

of parenchyma interspersed with

sclerenchyma.


elongate. Inter-cellular spaces.Not applicable Not applicable

Xylem vessels are present near the pith of

the fruit.

Pueraria lobata Primary

root

Region of periderm of about 5 rows of angular

and isodiametric cells with thin cell walls. The

cambium separates the cortex from the stele,

and is composed of an endodermis and

pericyle of one row.


elongate. Inter-cellular spaces.Not applicable Not applicable

Secondary xylem same as those within the

phloem, however there are regions of

anomalous tertiary growth adjacent to

individual vessels. Polyarch xylem. Many

areas of tertiary xylem and phloem are

also present and are dissected by

medullary rays.

Piper methysticum Primary

root

Region of periderm of 3 rows of angular and

isodiametric cells that are thick walled.45-75 35-60

Rounded and isodiametric. Inter-

cellular spaces (pith).Not applicable Not applicable

Primary tissues made up of angular and

isodiametric cells with very few inter-

cellular spaces. Within this, wide

medullary rays made up of l igneous

fibres and also xylem vessels. Scanty

paratrachial to vasicentric layers of

xylem cells abut these rays and are

differentiated by thinner walls and more

angular shape. Bundles of phloem are

contained within these areas of xylem.

Exterior to the cambium are further

bundles of xylem within the

parenchymous tissues.

Pteridium sp. Rhizome Outer epidermis of around 3 layers of rounded

and elongated cells with thickened cell walls.80-115 65-90

Angular and elongate, some

isodiametric.Unmeasured Unmeasured Dictyostele.

Solanum tuberosum Stem tuber

Outer thickened epidermis, cortex consists of

about 4-5 rows of angular and elongate cells

with thinner walls. The vascular cambium is

two layers of angular cells.

90-130 70-100Irregularly rounded and elongate or

isodiametric.Unmeasured Unmeasured Atactostele and bicollateral.

Spondias dulcis Fruit

Outer thickened periderm, and a cortical

region of approximately 5-10 rows of rounded

and isodiametric cells with thick cell walls.

85-160 55-95Angular and elongate, some

isodiametric. Thin cell walls.280-400 140-240

Eustele and closed collateral or

amphicribal concentric.

Syzygium malaccense Fruit

Thin epidermis of a single row of angular and

elongated cells, with a thicker exterior wall.

Several rows of small cells that are angular in

shape and more isodiametric in dimension

are below this within the cortex

75-120 45-85Angular and elongate, some

isodiametric. Few inter-cellular spaces.250-620 150-330

Eustele and amphicribal stellate with

polyarch xylem inside bundle.

Tabernaemontana

aurantiaca Fruit

Epidermis a single row of tangentially

flattened angular and elongated cells35-60 25-40

Rounded and elongate or isodiametric.

Inter-cellular spaces.175-370 100-230 Eustele and amphicribal concentric.

99


Cell

length

range

(µm)

Cell

width

range

(µm)


Vascular

bundle length

range (µm)

Vascular bundle


Tacca leontopetaloides Stem tuber

Periderm of 3 rows of r angular and elongated

cells with thin cell walls, with the outermost

row having a thicker external wall


elongate. Inter-cellular spaces250-530 100-270 Atactostele and bicollateral.

Todea sp. Rhizome

Outer epidermis of one layers of angular and

isodiametric cells with thickened cell walls.

Below is a broad region of fibres.

75-135 60-105Angular and isodiametric, some

elongate.Unmeasured Unmeasured Dictyostele.

Xanthosoma

sagittifolium Corm

Periderm of 4 rows of angular and

isodiametric cells with thin cell walls, with

the outermost row having a thicker external

wall.

55-80 50-60Rounded and isodiametric. Inter-

cellular spaces.90-270 80-230

Atactostele and amphivasal concentric.

Fibre sheath.

Zingiberaceae sp. 1Primary

root

Thickened periderm with around 10 rows of

thick walled cells that are rounded and

broadly isodiametric in dimension.

55-80 50-60Irregularly rounded and isodiametric or


Eustele and closed collateral. Fibre

sheath.

Zingiberaceae sp. 2Primary

root

Periderm of around 10 rows of rounded and

elongated thick walled cells. Thicker exterior

wall of the outermost layer. Vascular

cambium that is a single layer of more

angular and elongated cells.


elongate.160-309 112-240

Eustele and amphicribal concentric. Fibre

sheath.

100

Description of charcoal

Each of the specimens in the modern comparative collection was experimentally charred from

both dried and fresh state to assess the nature of morphological changes in the boundary, ground

and vascular tissues. SEM images provided high resolution records of the results of the charring

process. These morphological changes were described at an individual level for each specimen

in Appendix A, and are summarised briefly here. The conditions of charring were described

earlier within this chapter (see section ‘Experimental charring’), but it is important to note that

the temperature, time and access to oxygen were kept consistent for all of the specimens. The

charred specimens represent only one experiment in charring conditions, and morphological

changes may be different under alternative charring conditions of different temperatures, length

of exposure to heat, and oxidising conditions.

Boundary tissues

A small number of changes can occur in boundary tissues during charring. The epidermis or

periderm often becomes compressed or alternatively transforms into a region of solid carbon.

The carbonisation of the boundary tissues occurs in stem and root-derived tissues, as well as

fruits primarily within the samples charred from fresh state. There are also examples of this

carbonisation occurring in the samples that were dried prior to charring such as that within

Asplenium sp., Cordyline fruticosa, Dioscorea bulbifera, Inocarpus fagifer, Morinda citrifolia,

Spondias dulcis and Tabernaemontana aurantiaca. The remaining samples charred from a dried

state had epidermal or peridermal tissues that were either compressed or retained their original

morphology. Similarly, those tissues within samples charred from a fresh state were either

turned to solid carbon or were observed to be in the same condition as the uncharred sample.

These observations indicate that the samples charred from a dry state were more consistent in

terms of morphological changes than those charred from fresh state.

Ground tissues

Ground or conjunctive tissues can undergo a range of different morphological changes when

charred from fresh and dried states. First, the shape of the cells can change. Seven specimens in

the comparative collection evidenced cell shape change. One specimen, Barringtonia asiatica,

had more rounded cells rather than angular when dry-charred. The cells of another specimen,

Asplenium sp. became more angular in both samples. The remaining specimens had either partly

or wholly cells in the ground tissue that were originally rounded and had become more

irregularly rounded. These included Alocasia macrorrhiza, Dioscorea alata, Dioscorea

nummularia, Pandanus tectorius and Zingiber sp. in the dry-charred samples, but only A.

macrorrhiza, and another sample of Pandanus tectorius and Zingiber sp. in the wet-charred

samples.

Many specimens also had either inter-cellular spaces or whole regions of ground tissue

transform to solid carbon. This change was only slightly more common in the wet-charred

101

samples, which is an unexpected observation. The wet samples are more hydrated when

exposed to the high temperature during charring, and so greater modification is usually observed

in the form of carbonisation and tension fractures as the liquid evaporates. Carbonisation of

inter-cellular spaces was observed within six dry and wet-charred specimens, but these were not

the same specimens in both instances. Within the dry-charred samples, these included Alocasia

macrorrhiza, Artocarpus altilis seed, Barringtonia racemosa seed, Dioscorea bulbifera, Ficus

copiosa and Musa sp.2. The specimens with this variety of carbonisation in the wet-charred

samples included A. macrorrhiza, Colocasia esculenta, Dioscorea alata, .D. bulbifera, F.

copiosa and Musa sp.2. Almost half of the modern reference collection also had regions or

complete carbonisation of the ground tissue. Of the total 36 specimens, 15 specimens had

carbonisation in the dry-charred samples (42%), and 16 specimens had carbonisation in the wet-

charred samples (44%).

Cavities, tension fractures and vesicularisation also often occurred within both the wet and dry-

charred samples from the evaporation of water within the samples. The process of cavity

formation and fracturing is called rhexigeny (Hather 2000:41, 1993:4) and involves the

mechanical tearing of tissues under tension. The location of these tears in the ground tissue can

vary. Some were observed within the cambium, separating the cortex from the pith, while others

were near vascular tissues or were randomly located throughout the pith. Cavities formed within

12 of the dry-charred specimens, but were much more common in the wet-charred samples.

Over half of the specimens in the comparative collection had cavities form in the wet-charred

samples. This modification was observed in a total of 18 specimens. These included A. altilis

seed, Angiopteris sp., Barringtonia asiatica seed, B. racemosa seed, C. esculenta, Musa sp

1.and Xanthosoma sagittifolium, which only form cavities when charred from fresh state.

Alternately, Cyrtosperma merkusii only formed cavities within the dry-charred sample. Tension

fractures were also very common, forming in eight dry and wet-charred samples, but again these

were not the same specimens in both types of samples. Only Musa sp. 2., Pueraria lobata,

Pteridium sp., Spondias dulcis and X. sagittifolium had cavities form in both wet and dry-

charred samples.

Vesicularisation is the formation of air spaces by the explosion of cells under pressure.

Hather (2000:45) describes this process as occurring when “...the water content of cells heats up

and eventually boils, resulting in the rupture of the cell and a release of water vapour under

pressure. The escaping water vapour bubbles through the tissue, compressing cells and causing

the formation of vesicles.” The vesicular appearance is a by-product of the fact that some of the

cells are still visible as such but become much smaller and the cell walls are smooth with the

outline of cells on the internal surface. This form of cellular modification was observed in nine

dry-charred specimens and eight dry-charred specimens. These were mostly the same specimens

in both, with the exception of Angiopteris sp., Colocasia esculenta, and Cyrtosperma merkusii

102

which were only vesicular in the dry-charred samples and Dioscorea nummularia, which only

had vesicles in the wet-charred samples.

A number of changes can also directly occur within the ground tissue cells and affect

the appearance of these cells. Roughly one third of the reference collection had samples that

exhibited cell compression either regionally or throughout the ground tissue in the dry-charred

samples (n=12), and half of the collection had this modification within the wet-charred samples.

This was usually a by-product of the formation of cavities and tension fractures within these

tissues. Those specimens that only had cell compression within the wet-charred samples

included Angiopteris sp., Asplenium sp., C. esculenta, Ipomoea batatas, Musa sp.1, Tacca

leontopetaloides, and Todea sp. A smaller number of samples only had compression in the

samples charred from dried state, including Dioscorea esculenta, Inocarpus fagifer, Pueraria

lobata and Xanthosoma sagittifolium.

103

Table 5.10 Description of morphological modification within ground tissue of charred samples in the comparative collection

Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh

Alocasia macrorrhiza X X X X X X X X

Artocarpus altilis fruit X

Artocarpus altilis seed X X X

Angiopteris sp. X X X X X

Asplenium sp. 1 X X X X X

Asplenium sp. 2 X X X X

Barringtonia asiatica seed X X X

Barringtonia racemosa seed X X X X X

Colocasia esculenta X X X X X

Cordyline fruticosa X X X X X X

Cyrtosperma merkusii X X

Dioscorea alata X X X X X

Dioscorea bulbifera X X X X X X X X X X

Dioscorea esculenta X X X X

Dioscorea nummularia X X X

Epipremnum pinnatum X X X X

Ficus copiosa X X X X X

Ficus tinctorius X X X X

Ipomoea batatas X X X X

Inocarpus fagifer X X X X X X

Morinda citrifolia X X x X X X

Musa sp. 1 X X X X X

Musa sp. 2 X X X X X X

Pandanus tectorius X X X X

Pangium edule X X

Pueraria lobata X X X X

Piper methysticum X X

Pteridium sp. X X X X X X

Spondias dulcis X X X X X X X X

Syzygium malaccense X X X X X X X X

Tabernaemontana aurantiaca X X X X X X

Tacca leontopetaloides X X X X X

Todea sp. X X

Xanthosoma sagittifolium X X X X X X X

Zingiberaceae sp. 1 X X X X X X

Zingiberaceae sp. 2 X X X X X X

Carbonisation

Fractured/collapsed

cells Shallower cells

Inter-cellular

spaces carbonise Cavities

Tension

fractures

Compression of

cells

Thicker cell

walls

Thinner cell

wallsSpeciesCells

rounded

Cells

angular

Cells

irregular Vesicularisation

104

Table 5.11 Description of morphological modification within vascular tissue of charred samples in the comparative collection

Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh Dried Fresh

Alocasia macrorrhiza X

Artocarpus altilis fruit X X

Artocarpus altilis seed X X

Angiopteris sp. X X

Asplenium sp. 1 X X X

Asplenium sp. 2 X X X X

Barringtonia asiatica seed

Barringtonia racemosa seed

Colocasia esculenta X X

Cordyline fruticosa X X X

Cyrtosperma merkusii X X X

Dioscorea alata X X

Dioscorea bulbifera

Dioscorea esculenta X X X

Dioscorea nummularia X X

Epipremnum pinnatum X X

Ficus copiosa X X

Ficus tinctorius

Ipomoea batatas

Inocarpus fagifer X X

Morinda citrifolia X X

Musa sp. 1 X X

Musa sp. 2 X X

Pandanus tectorius X X

Pangium edule X X

Pueraria lobata X X X

Piper methysticum

Pteridium sp.

Spondias dulcis X X

Syzygium malaccense X X

Tabernaemontana aurantiaca

Tacca leontopetaloides X X

Todea sp. X X


Zingiberaceae sp. 1 X X X

Zingiberaceae sp. 2 X X

Cambium fractureSpecies

Phloem- cavity Phloem- carbon Bundle separates Cambium- carbon Fibre sheath-carbon Phloem compressed

105

Cells were also often fractured or collapsed in many of the wet and dry-charred

samples. This process often rendered regions of the ground tissue unrecognisable. Many of the

fruits exhibited this change, including Ficus tinctoria, Morinda citrifolia, Musa sp. 1, Pangium

edule, Pandanus tectorius, Spondias dulcis, Syzygium malaccense and Tabernaemontana

aurantiaca within either the wet or dry-charred samples. A small number of stem and root-

derived specimens had large areas of collapsed cells with exposed cell contents such as starch,

crystals and druses. These included Cordyline fruticosa, Epipremnum pinnatum, Ipomoea

batatas and Zingiber sp. In addition, a very small number of specimens exhibited signs that cells

became shallower during dry-charring, indicating a change in cell dimension. These included

Dioscorea esculenta and I. batatas.

Where specimens did not show signs of cell compression or collapse, many instead had

thickening or thinning of the cell walls. This can result from cells swelling and solidifying

during intense heating of liquids within the tissues. Within the dry-charred samples, Alocasia

macrorrhiza, Artocarpus altilis seed, Barringtonia asiatica seed, Colocasia esculenta, and

Dioscorea bulbifera all had cell walls that were thicker than those observed within the

histological thin sections. Only A. macrorrhiza and D. bulbifera had this occur within the

samples charred from fresh state. Conversely, a small number of samples had thinning of the

cell walls after charring. These included D. alata and Zingiber sp. in the dry-charred samples,

and D. esculenta and Zingiber sp. within the wet-charred samples. The sample of C. fruticosa

that was charred from dried state did not show signs of thickening or thinning of cell walls, but

instead had a pitted texture on the interior of the cell lining.

Vascular tissues

A smaller array of changes occurred in the vascular tissues during the charring process. The

root-derived specimens experienced less modification in parenchyma morphology. Only

Pueraria lobata had some rhexigenous tension fractures and carbonisation occur within the

vascular cambium, separating the secondary xylem from the phloem. This occurred in both the

wet and dry-charred samples of the species. The vascular bundles of the stem-derived specimens

and fruits often had significant morphological changes occur through charring. The thick non-

living lignified walls of the xylem are able to withstand the intense heat of the charring process

much better than the more fragile thin living tissues of the phloem that often contains sugars and

nutrients. The xylem was therefore consistently preserved in original condition, but the phloem

either turned to solid carbon or became a cavity.

The phloem became a cavity within 11 of the dry-charred specimens and 12 of the wet-

charred specimens, which represents just over a third of the 33 fruits and stem-derived charred

specimens. These included most of the yams (Dioscorea spp.) including Tacca leontopetaloides

and both Musa spp. Another 14 specimens exhibited the fusion of tissues within the phloem in

the dry-charred samples, consequently transforming these tissues into solid carbon. These

106

included both the fruit and seed of Artocarpus altilis, several of the Pteriodophytes, and three of

the aroids. Colocasia esculenta, Cyrtosperma merkusii and Xanthosoma sagittifolium had this

change occur within the phloem, but interestingly the only other aroid in the comparative

collection, Alocasia macrorrhiza, did not exhibit any changes in the dry-charred samples made

from the corm. However, change did occur within the wet-charred sample of A. macrorrhiza. It

is also interesting to note that the phloem within the corm of C. merkusii did not exclusively

turn to solid carbon in the dry-charred samples; some regions of the phloem were instead

compressed. This could indicate differential charring within the sample. Some specimens such

as Dioscorea bulbifera did not have recognisable vascular bundles within the charred samples

(this could be result of the sample selection and fracturing process) and thus could not be

described here. It is important to note that the arrangement of vascular tissues within the root

and stem-derived tissues and fruits did not change under charring. The xylem is still identifiable

as such, and the presence of the phloem as either carbon or a cavity enables description of the

arrangement of vascular tissues, and also the organisation of these tissues within the organ

where the fragment is large enough.

Other changes that could occur within the vascular bundles included the formation of a

cavity abutting the bundles, where these tissues have broken away from the surrounding

conjunctive tissue. This was only noted in a small number of specimens of the dry-charred

samples, which included Cordyline fruticosa, C. merkusii and Dioscorea esculenta. The fibre

sheaths surrounding the vascular bundles of the rhizomes of Asplenium spp. and Zingiber sp.

also turned to solid carbon within the dry-charred samples. Only one Asplenium species

exhibited this variation of tissue carbonisation within the wet-charred samples.

In summary, the morphological changes that can occur during charring need to be

considered during the identification process. Some significant changes to cell and tissue

morphology can occur when plant specimens are charred either from dried or fresh states and

these changes will inhibit any identification that is based solely on morphological patterning in

fresh samples. However, these changes described here are based upon particular charring

conditions, and so it is hard to gauge how these might differ under alternative conditions such as

different temperatures, length of exposure and oxidising conditions. An awareness of the nature

of these changes and an understanding of why these might occur are essential components of a

methodology that will aid classification of unknown archaeological parenchyma to a taxonomic

level with confidence.

Development of an Identification Flowchart Key

Through exploration of the morphology of ground tissues and vascular tissues separately, it

becomes clear that many taxa in the comparative collection are able to be differentiated from

one another. These tissues are the components of parenchyma most likely to be observed and

107

preserved within the archaeological record, and therefore the attributes analysed above can aid

identification of these specimens with a moderate-to-high level of confidence. Where taxa could

not be differentiated based on the morphology of one of these tissues, an identification

flowchart key is useful that combines all of the known diagnostic features of parenchyma within

the reference collection. Depending upon the presence or absence of vascular tissues, the

flowchart can guide identification of an unknown sample to various taxonomic levels based

firstly upon the arrangement of vascular tissues, then bundle morphology, and finally

considering cell morphology. If one attribute cannot be observed, another avenue allows

identification using other attributes. Sometimes it is only possible to narrow the list of potential

classifications, and the key is the first step in identifying unknown parenchyma. Further

examination of SEM and light microscopic imagery, along with consideration of geographic and

environmental boundaries for plant distribution can aid final identification.

Essentially, two flowcharts were created based on the morphological data collected

from the thin sections made from each specimen in the comparative collection. The first key is

the primary flowchart, and is usable if some vascular tissues are visible within an unidentified

fragment of desiccated or charred parenchyma. This chart starts by considering the arrangement

of vascular tissues, then the morphology of bundling, and finally the cell morphology is used to

differentiate between taxa. If particular attributes are not able to be observed, the key can at

least facilitate classification to the type of organ from which it derived (fruit, stem-derived or

root-derived), or to family level in some cases. There is more morphological patterning within

the vascular tissues of stem-derived tissues at family level, and particular vascular arrangements

can be seen throughout the specimens of a family. For example, collateral vascular bundles are

present in the members of the Dioscoreaceae family within the comparative collection, while

amphivasal bundles are present in all members of the Araceae family. The specimens of fruits

included in the comparative collection also have these types of bundles, but other aspects of

cellular morphology and charring characteristics differentiate these at family level.

The second key is usable if vascular tissues cannot be observed within the sample and

only uses attributes of cell morphology such as shape and cell lengths. Attributes such as the

presence of fibres, vessels, duct cavities and inter-cellular spaces were also used when possible.

Clearly some changes to boundary, ground and vascular tissues occur during charring and those

observed changes were incorporated into this key. This key may only be able to provide a list of

tentative classifications that are not usually from the same genus or family. This is because there

is a lot less morphological patterning within the ground tissue at these taxonomic levels. There

is significant overlap between fresh specimens, but particular characteristics of charring can be

used to differentiate these to some degree.

108

Sometimes several directions within the flow charts could be taken to arrive at the same

classification. This is because some species have several cell shapes or bundle arrangements, or

charring could affect cell shape or dimensions. If a junction is reached where the particular

attributes to further narrow down the list of possible classifications are not visible, then the data

in Appendix A containing detailed descriptions of the fresh and charred samples can be

examined. Where boundary tissues are present, these descriptions can be used instead to

differentiate between this list. Photographs and SEM images of the reference collection then

needed to be considered along with geographical data for the distribution of each of the species.

It was deemed useful here to adopt the determination system using identification criteria and

associated levels of confidence compiled by Paz (2001) and later used by Oliveira (2008). This

determination system has been used successfully by these researchers in the past to analyse

macrobotanical plant remains from a range of archaeological contexts in the Asia-Pacific region

(Barker et al. 2011; Barton and Paz 2007; Oliveira 2008; Paz 2001, 2005). Plant samples are

determined to taxa using the following criteria:

Non prefixed: Photographic reference(s) and/or illustration reference(s); reference material not

essential; exact fit of the taxonomic features, geographic distribution, and species citation in the

local flora;

Prob.: Flora citation, geographic area compatibility, an agreement with taxonomic details;

image OR illustration OR reference material (not necessarily an exact or good fit);

Cf.: All six categories may or may not exist; archaeological specimen resembles image OR

illustration OR reference material OR previous identification; flora, taxonomic details and

geographic area but with doubts;

Elim.: Lowest level of confidence for a binominal determination to species level, but with no

access to image, illustration or reference material; taxonomic description, geographic area and

other species of same genus were eliminated from local/regional flora (= likely candidate);

Suffix 'type': Very low level of confidence, used only at family and genus level of

determination; shape of specimen fits the geographic distribution, some morphological

characters, and may be in the local flora;

Form shape description: None of the six types of information exist (image, illustration,

reference collection, flora, taxonomic details and geographic area), but the specimen is

distinctly a seed, nut fragment or a certain plant part.

The identification process for archaeological parenchyma incorporated a large amount

of data derived from the modern comparative collection to provide classifications with varying

levels of confidence, expressed using the determination system of Paz (2001). The two

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identification flowchart keys enable the classification of unknown plant samples that have

varying levels of tissue preservation to at least the type of organ from which fragments have

derived. This information is crucial to the interpretation of plant use within a site or landscape.

The presence of crops is a good indicator of at least low-level agricultural practices. Here, this

information will be used as stand-alone data and to corroborate the data collected from the

analysis of soil samples for ancient starch residues. The presence of starch and parenchyma

from a particular family, genus or species will provide complementary records for the presence

of economic and famine species within the sites of Talasiu, Leka and Heketa on Tongatapu in

the Kingdom of Tonga.

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Figure 5.15 Flowchart 1 used as an identification key to identify unknown parenchymatous samples when vascular tissues are visible

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Figure 5.16 Flowchart 2 used as an identification key to identify unknown parenchymatous samples when no vascular tissues are visible

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PART TWO- DEVELOPMENT OF

PREHISTORIC AGRICULTURE IN

TONGA

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Chapter 6 Sites and Field Sampling Strategy

This chapter outlines the methods used to extract botanical remains from three archaeological

sites on Tongatapu of varying antiquity. The archaeobotanical program builds upon the work

carried out to date within Polynesia (Chapter 2) and attempts to answer the key research

questions regarding the role of plants within colonising subsistence and migration episodes in

Western Polynesia and the later development of social complexity through the establishment of

the maritime Tu’i Tonga chiefdom. Revised protocols are established for both field and

laboratory methods, building on those currently used both in the Pacific and elsewhere

(Chapters 3-4) through new experimentation. Experiments were conducted in reaction to

problems highlighted within previous studies in terms of the success of extractions within

differing deposits, and the risk of contamination from laboratory equipment. The results of these

experiments were used to provide data on the presence of plant taxa within well-dated cultural

deposits that are presented and discussed in Chapters 8 and 9.

Methodology for field sampling of archaeological sediments

Site selection

During fieldwork in November 2011, sediments were sampled from open archaeological sites

using flotation and bulk sampling for microbotanical analyses. Comparisons of identified taxa

within sediments were made on a spatial scale across north-eastern Tongatapu, to provide a

scope for the chronology of the introduction of crops and development of production systems.

This incorporated test-pitting at two known sites on the south-eastern edge of the Fanga’Uta

Lagoon, and one site at Heketa on the northern coast underneath the ‘esi or chiefly back-rest

monolith. Talasiu (TO-Mu-2) and Leka (J17) are both located in the Mua region within the

village of Lapaha and are now inland although Talasiu is located on the edge of an old

palaeoshore (Dickinson 2007). The ‘esi (TO-Nt-2) is attributed to the construction phase at

Heketa initiated by the 11th Tui Tonga within local traditions, and is considered contemporary

with the Ha’amonga trilithon of the same complex.

These sites had already been located, surveyed and sampled for archaeological material

by Clark and others (2008), Golson (1957), McKern (1929), Poulsen (1987), and Spenneman

(1986, 1989) in archaeological projects on Tongatapu. McKern (1929) carried out the first

major archaeological survey of the Tongan archipelago as part of the Bayard Dominick

Expedition of the Bernice P. Bishop Museum in 1920-21. Mapping and excavation of the tombs

and enclosing ditch at Lapaha and Heketa was a particular focus of his work, and his labelling

of the tombs has been used in all subsequent archaeological research. Langi Leka (J17) and the

‘esi at Heketa (TO-Nt-2) were among the monuments mapped by McKern. Golson (1957)

carried out a limited survey of Tongatapu and offshore islets, exploring the potential for using

ceramics as cultural markers. During this survey Golson excavated a section of a site named by

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Spenneman TO-Mu-2 near the village of Talasiu, and reported on the potential of the pottery-

bearing midden. Golson encouraged one of his students, Jens Poulsen, to further explore the

ceramic typological sequence within Tongatapu. Poulsen (1964, 1967, 1987) subsequently spent

a year carrying out a detailed program of excavation around the Fanga’Uta lagoon.

Following extensive archaeological research in the late 1960s by Davidson (1969,

1971), Groube (1971) and others that focused on late prehistoric sites and the construction of a

Tongan culture history, Spenneman (1986) spent some months in Tonga attempting to locate

post-Lapita sites in accordance with the research prerogatives of the Tongan Dark Age Project

initiated at the ANU. He returned to the site at Talasiu (TO-Mu-2) and sampled the midden for

ceramic and organic material for radiocarbon dating, reporting on the presence of decorated and

plainware pottery within the same context. Most recently, Geoff Clark returned to Tongatapu in

2006–2008 to assess the construction sequences of the monumental sites of Heketa and Lapaha

as part of two Australian Research Council (ARC) grants exploring the development of social

hierarchy in Tongan prehistory.

These surveys of the archaeological landscape on Tongatapu and subsequent

excavations have provided valuable insights into the nature and timing of cultural deposits. The

sites were all noted to have intact deposits with little disturbance related to subsequent

occupation. The morphology of the material culture and age ranges of dating material (shell and

charcoal) also indicated that each of these sites represented a different chronological period

within Tongan prehistory spanning over 2000 years. The presence of refuse such as shell,

fishbone and charcoal within the deposits at the sites also pointed to the likelihood that the sites

were where domestic practices such as cooking and rubbish disposal took place. These three

sites were selected for my PhD research based on site preservation and the reasonable

possibility that macrobotanical remains might be recovered that would allow archaeobotanical

exploration of plant use in Tongan prehistory.

Field methods

High-resolution excavation techniques were employed at Talasiu, Leka and Heketa to gain

information about subsistence practices and vegetation history at the three sites. Botanical,

faunal and artefactual remains were collected from test-pits of around 50x50cm using simple

bucket flotation and wet sieving. These techniques are recommended for use in tropical climates

(Fairburn 2005b; Pearsall 2010), where access to water and technical equipment can be limited.

Some further revision of these techniques was required due to issues that were encountered

during fieldwork, and therefore a revised protocol was established that suited the conditions

specific to Tongatapu during the 2011 season. The methodology can thus be broken down into

four sequential activities:

1. Excavation and bulk sampling

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2. Bucket flotation

3. Wet sieving

4. Sorting, identification and quantification

Excavation:

Test pits of 50x50cm were marked out using string and excavated in 5cm arbitrary levels,

referred to as ‘spits’. There was slight variation in the size of the test-pits where contemporary

cultural deposits had been already sampled in previous test-pits at particular sites. If a change in

stratigraphy was noticed during excavation, a new level was begun. All excavated material was

placed into buckets for flotation with a water-proof label. Any observed charcoal concentrations

were sampled in situ and wrapped in aluminium foil. The charcoal locations were then recorded

on datasheets for each spit. The datasheets also included detailed information upon the soil

texture, colour, sorting, and inclusions. Bulk soil samples of around 100g were retained from a

10cm-wide bulk soil sampling column that was measured out and marked on the test pit wall,

with samples reserved for microbotanical analysis.

Bucket Flotation:

The excavated material from each level was weighed using a spring balance, and the volume

was calculated by pouring the sediment into a bucket with volume marks (litres). This

measurement was then recorded in a flotation logbook. The material was then divided into

buckets, so that each bucket was filled to one-third (33%) of its volume. Water was added until

the bucket was nine-tenths (90%) full, and the material was gently stirred by hand. This mixture

was left to settle and deflocculate for around 5-10 minutes (after Fairburn 2005b).

A flotation sieve was set up by pegging muslin mesh into a bucket with large holes cut into the

base. To recycle water, this rested on two cut branches that sat atop a plastic washing tub. The

excavated material was then decanted into the muslin, allowing any material that was floating

on the surface of the water to be separated from the heavy residue that had sunk to the bottom of

the bucket. More water was then added to the heavy residue, and the process of settling and

decanting was repeated at least twice until no more material was visible floating on the surface.

The muslin was then unpegged from the lip of the bucket and tied to create a sack that held the

‘flot’ sample with a waterproof label showing the site, test-unit number, level number and date.

Finally, these flot samples were placed onto a string line to dry in the sun, and then put into

labelled aluminium foil envelopes in zip-lock bags.

Wet sieving:

The remaining heavy residue was taken to a new station for wet sieving through a 3mm mesh

sieve. Again water recycling techniques were employed by keeping water in two large plastic

washing tubs. The sieves were immersed in these tubs to just below the rim and agitated.

Keeping the rim out of the water ensured that no larger material floating on the surface (such as

leaves) could enter the sieve while being agitated. Once all dirt was removed from the sample,

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the remaining material was placed onto a plastic rice sack with a water-proof label to dry in the

sun.

Sorting, identification and quantification:

Some basic sorting of the dried material was carried out in the field. Heavy residue from each

level was dry-sieved using a 6mm mesh sieve to create a large (>6mm) and small (<6mm)

fraction. Each fraction was sorted and recorded separately. These fractions were placed onto

trays and sorted using tweezers into basic material types: ceramics, lithic material, other

artefacts, bone, shell, charcoal, seeds and other organics. The sorted fraction were then bagged

and labelled. After being returned to the ANH laboratories at the Australian National

University, further sorting and quantification of both the heavy residue and the flot samples was

carried out. The heavy residue was sorted in much the same way as that in the field, and weights

of the various artefacts and material types were recorded. The flot samples were also sorted into

material types such as seeds, wood charcoal, charred root and tuber parenchyma, land snails,

bone and insect remains. The weights and counts of these were then recorded on datasheets

which were then digitised.

Figure 6.1 Map showing location of archaeological sites included in this study from Tongatapu

Site descriptions

Talasiu (TO-Mu-2)

All three sites were cultural midden deposits of varying sizes and concentrations. Talasiu (TO-

Mu-2) in the Mua region is a late Lapita-associated site which was first excavated by Golson

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(1957). Golson’s field-notes (1957) describe the density of shell and pottery within his

excavation units, causing his team to halve the size of the original unit from 10ft² to 10x5ft.

During survey, Spenneman (1986:38) noted that the midden site extended as far south as the

Langi or monumental stone tombs (J18-J19) but was distinct from another nearby midden (TO-

Mu-67). Spenneman sampled the midden and recorded a mix of decorated and undecorated

pottery, stone flakes, adzes and adze fragments, and a coral abrader alongside some fragmented

human remains.

Evaluation of the topography and geology of the Mua region indicates that the midden

was originally deposited on the shore of the Fanga’Uta lagoon; however, later extensive land

reclamation using coral rubble, limestone and soil in-filled the inter-tidal lagoon flats, and the

site is now approximately 200m inland from the current lagoon shore, except to the north where

an inlet cuts close to the site (Dickinson 2007). The midden stretches approximately 100m along

the old palaeoshore (Spenneman 1986). The site could have been an attractive location for

settlement in prehistory, with a small limestone solution channel and spring located near the site

that provides a source of fresh water and feeds into the lagoon (Spenneman 1986; Valentin and

Clark 2013). Several cultural strata are present at the site, the earliest of which is composed of

many cooking and other domestic features cut or embedded into the reddish sterile clay. Above

this is the deposition of a dense midden of near shore and inter-tidal shellfish and fish from the

lagoon. Cut into this midden and the earlier domestic features are a number of complete and

incomplete burials, believed to be mostly contemporary with the deposition of the midden from

2700-2500 cal BP (Valentin and Clark 2013).

The only test pit excavated at Talasiu (TP2) for this project was a 50x50cm test-unit

that sampled the cultural midden, and cut into the sterile basal clay by 5cm. The whole unit was

a total of 100cm in depth, with every 5cm of deposit excavated, processed and described as a

separate level or spit. All excavated material from these spits was processed using flotation and

wet-sieving to isolate botanical, faunal and cultural material. A total of 19 spits were excavated

and processed for botanical remains. 100gm bulk samples were taken from each level within a

10cm sampling column marked out on the north-facing profile of TP2, where stratigraphic

levels were most distinctive, for starch analysis.

Leka (J17)

Langi Leka (also known as Lekamakatuituioha or ‘Puipui’) is a four-tier monumental tomb or

langi (J17) built during the classic Tu’i Tonga chiefdom phase of Tongan prehistory, and is said

to be associated with Tu’i Tonga Tulunga (McKern 1929:41). The langi is located about 400m

inland from the Fanga’Uta lagoon in the community known today as Lapaha, within the Mua

region of Tongatapu. Geophysical survey at Langi Leka indicates that the langi had been built

on top of an older cultural deposit. Initial excavations were carried out in 2008 to assess the

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nature and timing of this older occupation through test-pitting. These prior excavations also

shed light on the construction sequence for the langi. Attempts were made to relocate TP1which

had been abutting Langi Leka. It was believed that TP1 had been found, and TP2 was

subsequently excavated parallel to this location further west. A 2x1m test pit was measured out

and extended north from the base of the first tier of the langi. The red clay and coral

construction rubble debris was recorded and then removed in bulk, so that the darker cultural

material below could be excavated and processed in a 100x50cm test pit in the northern end of

the excavation. It turned out this unit missed the more dense shell midden that pre-dated Langi

Leka by about 5m. Despite this, seven 5cm levels were processed for botanical remains below

90cmbd through flotation and wet-sieving.

In a second attempt, another test 2x1m unit (TP3) was opened up approximately 2m to

the east of TP2. TP3 also abutted the langi, and was sampled from 90cmbd within the cultural

material using the same techniques employed for TP2, but this time from within a 100x50cm

test pit in the southern end of the excavation. Cultural deposits were encountered in both TP2

and TP1, although these were not of the same density noted during previous excavations. TP3

was abandoned and back-filled after excavating to 110cmbd. TP1 was finally located after a

system of shovel-test pitting along the base of Langi Leka was employed and the modern fill

was quickly removed. The northern baulk was cleaned and chosen for sampling the cultural

deposit observed at 95cmbd. A 25x50cm test unit was cut into the baulk, and material above

95cm was discarded. Sampling began below this in the dense cultural midden with every 5cm

level excavated, processed and recorded in the same manner as other test pits made at Talasiu

and Leka.

Heketa (TO-Nt-2)

The final site chosen for excavation and botanical sampling was located in the north-east at

Heketa near the ‘esi’ or chiefly backrest known as Makafakinanga (TO-Nt-2) situated close to

the Ha’amonga a Maui trilithon (TO-Nt-1). This complex is composed of nine stone structures

(Nt-1 to 9) that represent a short period of monumental stone architecture construction, forming

an early centre of the classic Tu’i Tonga chiefdom (Clark and Reepmeyer 2014) or state (Kirch

1994). Tongan traditions associate most of the structures with the 11th Tu’i Tonga, Tuitatui,

while an earth mound is tied to the 10th Tu’i Tonga, Momo (McKern 1929). Dates for the

construction of the stone architecture all fall within the 14th century (Clark and Reepmeyer

2014; Spenneman 2002), but several earlier deposits have been located underneath these

structures dating to the 12th-14th century AD, indicating that the site may have also been a

significant place associated with early Tu’i Tonga Hikuleo for several centuries before this. In

traditions the centre of the chiefdom was moved south to Lapaha by the 12th Tu’i Tonga

Talatama.

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This original test pit (TP1) had been excavated in order to assess the construction

sequence for the ‘esi or backrest monolith. The aim was to cut into the baulk of this original test

pit to sample a cultural midden and charcoal deposit that predates the erection of the ‘esi which

had been recorded and dated previously. With this in mind, a 50x50cm test pit (TP2) was

marked out about 1.5m away from the ‘esi. The first test pit was excavated to 90cm below

datum (bd), when the sterile clay was encountered. Each 5cm level was sampled for botanical,

faunal and artefactual material through flotation and wet-sieving. Assessment of the profile and

excavated material suggested that this test pit had only sampled the edge of the feature exposed

in the original test pit.

Further test pits were then used to locate the looser and more mixed backfill of TP1, and

then this backfill was removed to expose the original walls of the test pit. The final unit, TP3,

was excavated into the cleaned face of the baulk between TP1 and TP2. TP3 was a 50x30cm

test unit that was excavated to 105cmbd below datum, where the sterile clay was again

encountered. All material from each 5cm level after 40cmbd was processed using flotation and

wet-sieving. The material above this point was all sterile red clay which capped the cultural

deposits and topsoil, and had already been sampled within TP2. This strategy allowed specific

targeting of the cultural deposit within this test unit.

Stratigraphic descriptions

Talasiu (TO-Mu-2)

The whole test unit consisted of very compact shell midden with limited sediment matrix. There

was very little if any topsoil, and below this some distinctions can be made within the midden

deposit. The top 20cm (Layer 1) below the current surface level contained a disturbed and

highly fragmented shell deposit with a light grey brown silty matrix. Charcoal, coral and

limestone inclusions were very common. The presence of many small rootlets combined with a

lack of protective topsoil contributed to the disturbed nature of this uppermost deposit. Below

this was a region of more compact shells to a depth of around 35cmbd (Layer 2) that were also

highly fragmented within a coarse yellow brown silty clay matrix. Higher concentrations of

charcoal were noted throughout the deposit and possible volcanic ash lenses. The transition

between Layer 2 and 3 is not level, indicating that the surface of Layer 3 was undulating.

Layer 3 was a thick (35-60cmbd) deposit of loose large shell fragments with a friable

yellow red clay matrix and large amounts of charcoal throughout. More pottery was located

between 50-60cmbd, and large fragments of Tridacna were found at the base of this deposit. A

small feature (Feature 1) was cut into Layer 3 from above and had more compact shell. It is

possible that this was a disturbance from a tree root observed within this deposit. Layer 4 was

another undulating layer below this with very compact large shell fragments, charcoal

fragments, and a red clay matrix that extends to 80cmbd. At the base of this layer was another

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possible feature (Feature 2) which was rounded with a diameter of 8cm, and cut into Layer 5. A

higher density of shell was noted in the north-west corner of the test unit. The final and bottom

layer (Layer 5) of midden was a reddish clay sediment with small crushed shell and charcoal at

the base of the midden. The base of the layer slopes towards the north-west corner, and so this

was recorded as Feature 3, however this may just reflect the undulating nature of the original

ground surface. Importantly, there were also small fragments of dentate-stamped and plainware

pottery found inter-mixed throughout the lower half of this assemblage, and near the base of the

test unit at 85-90cmbd in the south-west corner. Sterile orange brown clay was encountered at

95cmbd.

Figure 6.2 Stratigraphic diagram of cultural deposits within Talasiu TP2

Leka (J17)

All three test pits at Leka revealed an interesting construction sequence for the langi or tomb,

with features that were associated with the ditch for slotting the stone facing of the first tier of

the tomb into place, and limestone cobbles providing support for these. Below these

construction features were cultural deposits associated with occupation at the site prior to the

development of monumental architecture at Lapaha. This occupation seemed to be centred near

the location of TP4, where the deposit was deepest and contained the highest concentration of

archaeological material.

The stratigraphy observed within TP2 represents a range of deposits associated with the

construction of the langi, and the older cultural surface upon which the langi was built. The

uppermost layer below the surface, Layer 1 was a coral gravel deposit with red brown clay

matrix that was more concentrated near the surface and more diffuse towards the base. This

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layer is most likely construction debris from the langi. Below this was deposit of reddish brown

clay (Layer 2) with dispersed charcoal that capped an older cultural deposit (Layer 3). Layer 3

was a medium brown silty clay cultural deposit with many charcoal inclusions. Some red clay

from the base of this layer was inter-mixed with the cultural material from 105-125cmbd. This

layer sat upon the surface of the sterile red brown clay at 125cmbd.

In TP3 a shallow topsoil deposit (Layer 1) was visible below this surface from 5-15cm

below the datum. Layers 2-5 were various coral gravel fill deposits within the ditch cut to allow

the placement of the limestone tomb stones. At the base of this ditch was a surface of large

limestone cobbles up to 20cm in diameter that were used to hold the beachrock slabs in place.

Layer 2 also appeared to extend out to be a coral gravel path that surrounded the base of the

langi. Layer 6 was a sterile red brown mixed clay in which was a tephra ash lens (Layer 7). It is

believed that the large amount of sediment that created this layer was the result of ongoing

tephra ash falls after 1000 BP. These deposits capped the mid-brown silty clay cultural layer

(Layer 8) with small dispersed shell fragments and charcoal. This deposit was the only layer

sampled for flotation and microbotanical analysis.

The stratigraphy of TP4 resembled that seen within TP2 and TP3, although the cultural

deposit below 95cmbd contained a more dense concentration of shell, bone and charcoal.

Similar to TP2, this cultural deposit was located below various mid-reddish brown clay deposits

(Layers 1-3). The top of the cultural deposit was a mid-brown silty clay layer (Layer 4) from

95cmbd, with some dispersed shell, charcoal, fishbone, fire-cracked rocks and small limestone

cobbles. Shell midden composed the lower half of the cultural deposit (Layers 5-6) from

125cmbd, and had internal stratigraphic differences. A mid-brown silty matrix was observed at

the top (Layer 5), above a more red clay matrix at the base (Layer 6). The frequency of charcoal

within the deposit increased between 135-140cmbd. By 140-145cmbd the cultural deposit began

gradually transitioning into red clay with fewer shells and charcoal. The base of the excavation

was sterile orange brown clay (Layer 7).

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Figure 6.3 Stratigraphic diagram of cultural deposits within Leka TP2

Figure 6.4 Stratigraphic diagram of cultural deposits at Leka TP4

Heketa (TO-Nt-2)

The initial test pit at TO-Nt-2 (TP2) revealed the edge of two deposits, one possibly related to

the construction of the ‘Esi, and the other deriving from a pre-stonework phase of occupation at

the site. Below the topsoil within this unit was a layer of red brown volcanic clay to a depth of

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around 20-25cm below datum (bd) (Layer 1). Below this was a layer of beach-rock sand debris

inter-mixed with some of this red brown clay to 25-30cmbd (Layer 2). A dark brown clay

deposit with some humic material was beneath this to 30-35cmbd (Layer 3), and capped the

cultural material. Layer 4 was a deposit of cultural material with dark brown clay matrix and

charcoal fragments which was observed below these surfaces. The density of cultural material in

this deposit was sparse. The base of this feature was sloping towards the south, and so the

deepest point of the cut was at 70cmbd in the western-facing profile at the south-east corner.

The shallowest point of the base of the deposit was at 53cmbd. A small pocket of shells

followed the contour of the base of this deposit, about 3cm above the sterile clay. This deposit

was possibly cut into another older occupation layer that had higher concentrations of shell,

coral and charcoal and thus appeared darker from 70-93cmbd within the profile (Layer 5). The

base of this deposit grades to less shell and more charcoal at the base. Both cultural deposits sat

on top of a surface of sterile orange brown clay (Layer 6). This test pit was dug to

approximately 99cmbd when the sterile clay was encountered.

The profile of stratigraphy within TP3 mostly resembled that of TP2. Red brown

volcanic clay below the topsoil extended to a depth of 25cmbd (Layer 1). Below this was the

same beach-rock sand inter-mixed with this clay (Layer 2), most likely related to the shaping of

the limestone slab for the ‘esi. This layer of debris capped a cultural deposit (Layer 3) at 30-

35cmbd. The cultural deposit consisted of dense large shell and charcoal fragments with a dark

silty loose clay matrix. There was some tree root disturbance within the deposit in the south-

west corner, from 45-60cmbd. Near the base at 85cmbd was a white ashy lens (Layer 5) within

a deposit of concentrated burnt crushed shell, charcoal, large whole shells, and many diodont or

puffer fish spines (Layer 4) from 80cmbd to the base of the feature. Very high densities of

mussel shell and a whole Lambis was located directly underneath Layer 5, grading to higher

concentrations of Diodontidae spines in with medium orange brown clay from the base of the

layer. The base of the deposit was encountered at 95cmbd, where the feature was cut into the

orange brown sterile clay seen in TP2 (Layer 6).

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Figure 6.5 Stratigraphic diagram of cultural deposits within Heketa TP3

AMS dating of cultural contexts

In order to identify samples for dating, the wet-sieved, flotation, and in-situ charcoal samples

were sorted into those that could be identified as coconut, other endocarp or nuts, and other

charcoal (wood and parenchyma). Coconut endocarp was identified based on the surface

texture, which consists of a ‘cross-hatched’ type of pattern where clusters of three or four

elongated parenchymatous cells are orientated at 45 degree angles to each other, as well as the

thickness and density of the cross-section. Coconut is also very difficult to fracture, due to the

density of the endocarp, but when it does fracture it does so relatively evenly and cleanly. The

methods employed to extract macrobotanical remains from these sites were successful in

producing small amounts of coconut from the wet-sieved material and in situ samples at all

three sites. In order to develop a chronology for these sites, three samples of charred coconut

endocarp were selected from spits (levels) located near the top, middle and bottom of one test-

pit from each site for dating at the Waikato Radiocarbon Dating Laboratory (WRDL).

The results of AMS dating indicate that all three sites are from separate and relatively discrete

time periods within Tongan prehistory. The midden at Talasiu (TO-Mu-2) can be dated to

around 2750-2650 cal BP, and appears to have accumulated over a period of around 100 or less

years. All three radiocarbon samples had narrow age ranges that overlapped very closely with

one another, indicating a relatively short depositional period. This site therefore represents

refuse from a settlement that is on the cusp of late-Lapita and Ancestral Polynesian Society

(APS). These dates are supported by the ceramic assemblage from Talasiu, which is composed

primarily of plain ware with a few dentate-stamped sherds in lower levels of the midden (Clark

et al. In press; Golson 1957; Spenneman 1986).

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Figure 6.6 Calibration of radiocarbon dates from Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2)

Occupation underneath Langi Leka (J17) can be dated to around 1300-1000 cal BP, and

so falls within the Formative Period (1550-750 BP) in Tongan prehistory (see Chapter 1), of

which little is known (Burley 1998:365-8; Davidson 1979). The abandonment of pottery

traditions around this time leaves an impoverished archaeological record, with a total of only 16

sites on Tongatapu representing these 800 years of occupation. The cultural deposit sampled for

radiocarbon dating represents another relatively short period of deposition, with all three date

ranges overlapping within a 100-200 year period.

Finally, the sampled Heketa (TO-Nt-2) material was from two deposits. One is around

800-600 cal BP and at the end of the Formative Period, while the other is a later deposit that is

related to the development of early monumental architecture in Tonga during the Classic Tu’i

Tonga chiefdom after 600BP (Burley 1998:368-79; Clark and Reepmeyer 2014). Two

radiocarbon samples were from this lower and earlier deposit, and the remaining sample

originates from the more recent feature and fill that caps this older pre-stonework architecture

surface.

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Chapter 7 Laboratory Methods

A combination of micro- and macrobotanical techniques was implemented to research and

identify plant use at three stages in Tongan prehistory. Sites were selected based on the results

of previous archaeological investigations on Tongatapu and sampled for botanical remains using

current archaeobotanical methods, modified for tropical environments. A combination of

flotation, wet-sieving and bulk stratigraphic sampling was used to extract all micro- and

macrobotanical material from each test-pit. Laboratory processing of these botanical remains

built on current techniques after experimentation revealed issues with contamination in the

laboratory environment and also methods for the dispersal of microcharcoal concentrations

within archaeological sediments, and the isolation of starch during heavy liquid separation. A

revised protocol for starch extraction is published here for future use in microbotanical analysis.

The extracted starch and parenchyma was analysed using both light microscopy and SEM, but

was then classified to taxa using a combination of multivariate statistical analysis in the form of

Discriminant Function Analysis, identification flowchart keys and visual checking of matches

that is outlined in Chapter 8

Microbotanical analysis: Starch residues

Experimentation with starch extraction techniques

As emphasised within Chapter 3, a number of previous technical studies of starch residue

extraction and processing from sediments have highlighted issues with current protocols, such

as sampling strategies, contamination and the use of destructive chemicals (Barton et al. 1998;

Coil 2003; Crowther 2009; Korstanje 2003; Parr 2002; Therin and Lentfer, in Torrence 2006b;

Torrence 2006b; Torrence and Therin, in Torrence 2006b). New protocols are constantly

developed to address the effects of different taphonomic, environmental and laboratory

conditions. In the current study, several experiments were designed to solve issues that arose

during the first round of laboratory processing, especially potential contamination from the

chemicals and equipment used. This experimentation sought to deal with this potential

contamination in the laboratory setting, as well as issues with the removal of micro-charcoal

that can inhibit viewing of starch granules on glass slides and the recycling of heavy liquid. The

results of these experiments enabled the development of a revised protocol that suited the nature

of the archaeological deposits being sampled and the laboratory equipment available at the

ANU.

Experiment One: Potential for starch contamination from Calgon, de-ionised water, filter mesh,

LST and Glycerol

The risk of contamination during post-excavation processing has been outlined in previous

research by Loy and Barton (in Torrence 2006b), Laurence (2013) and most recently Crowther

(2014). Experiments were designed to investigate the potential for contamination from materials

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used to process the archaeological sediments. To do this, each material was independently tested

for the presence of starch, and any observed starch was recorded and counted.

Calgon

Firstly, powdered Calgon or sodium hexametaphosphate was tested by mixing the powder with

de-ionised water to produce four 500ml samples of 5% Calgon. A magnetic mixer was added to

each of the samples, and these were then placed on a hotplate set to 20˚C to allow the Calgon to

dissolve into the de-ionised water. Once this had occurred, the samples were each filtered

through a 10µm laboratory-grade-filtration mesh. The mesh was then cut into three parts,

mounted onto slides, and covered with a cover-slip. Mountant was not added to the samples, as

these were constructed only as temporary slide mounts. The slides were then viewed using light

microscopy in both brightfield and polarised light.

The results of this experiment suggested relatively high numbers of starch contaminants

from powdered Calgon. Sample 1 had a total of 35 grains, Sample 2 contained 12 grains,

Sample 3 had 69 grains, and Sample 4 had 37 grains. The predominant starch types encountered

were taxonomically identified as wheat (Triticum spp.), and maize (Zea mays). It is possible that

contamination of the Calgon occurred in the laboratory storage for the Department of

Archaeology and Natural History, as the bag had been left open for a time. It is also plausible

that some contamination can occur even within laboratory-grade Calgon during manufacture, as

many companies produce both Calgon and powdered maize (along with other dehydrated or

milled plant products).

To resolve this issue and enable Calgon to be used as a deflocculant during processing

of the archaeological samples, the 5% Calgon/de-ionised water mix was filtered through a 5µm

laboratory filtration mesh to remove any potential starch contaminants. The filtered mix was

then always covered unless being added to soil samples in starch extraction processes to break

down clay particles.

De-ionised water

Four 500ml samples of de-ionised water were processed in a similar manner to the Calgon. The

beakers were poured through a circle of 10µm filtration mesh and the filter paper was then cut

into three parts and mounted on slides as temporary mounts. No starch was observed within

these samples during light microscopy, and so it was concluded that de-ionised water could not

be a source of starch contamination when used in extracting starch from archaeological

sediments.

Filtration mesh

Four circles of 10µm mesh laboratory-grade filtration mesh were dampened with de-ionised

water, after previous experimentation revealed that this was not a potential source of starch

contamination. These circles were then each cut into three parts, placed onto slides, and then

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covered with a coverslip. Light microscopy revealed that very little starch can be found on

filtration paper, with only one to two grains observed on any of the samples (Sample 2), and

therefore these are also not a significant source of contamination during processing of

archaeological sediments.

Lithium hexametaphosphate (LST)

Two samples of unused and two samples of recycled LST heavy liquid at 2.0sg were also tested

for starch contamination. These were filtered through individual rounds of 10µm filtration

mesh, and cut into strips before being placed on slides as temporary mounts. These slides were

then observed using light microscopy and any observed starch morphotypes were recorded. No

starch was observed within any of these samples, indicating that these are not sources of starch

contamination during processing.

Glycerol

Glycerol was the mountant chosen to create permanently mounted slides for both the

comparative collection and the starch extracted from archaeological sediments. It has a high

refractive index and ensures starch is preserved and protected from enzymatic attack, while also

allowing starch granules to be rolled. To test whether the Glycerol used in the Palynological

Laboratory in the Department of Archaeology and Natural History could be a potential source of

starch contamination, four slides were produced with 100µl of Glycerol on each. These slides

were covered with a cover-slip, and then observed using light microscopy. Three wheat starch

granules were found in total on these four slides, and so this material is a potential source of

starch contamination, but the contamination is very small.

Conclusions

These experiments assessed the amount and types of starch within a number of standard or

regularly employed chemicals and materials used to extract starch residues. Of the five materials

tested, only three contained any visible starch. Glycerol and filtration paper had very small

amounts of starch, with less than three granules observed in any one sample. Based on these

results it was decided that the use of glycerol and filtration paper within the current protocol was

acceptable and required no further processing. In contrast, the test involving unfiltered Calgon

highlighted that this material could be a significant source of contamination from modern wheat

and maize starch. Up to 69 starch grains were observed in each of the four samples. These

findings indicate that a major revision of the deflocculation process was required to enable

archaeological sediments to be processed without the risk of contamination. In light of this, it

was decided that the pre-mixed Calgon needed to be filtered through a 5µm filtration mesh prior

to use. All other materials were acceptable for use within the revised laboratory protocol.

Experiment Two: Removal of charcoal from samples

The soil samples collected from Talasiu, Leka and Heketa were taken from shell middens of

various densities, and it was noted that there were high concentrations of microcharcoal present

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in the soil matrix. Microcharcoal can make light microscopy difficult by obscuring the visibility

of any potential starch grains, and so needs to be either removed or dispersed in starch

extraction. Several experiments were carried out to establish whether particular methods were

effective in this, and also to gauge the effect these methods had on starch residues. These

replicated and built on experiments carried out by Crowther (2009:62-82).

Lithium hexametaphosphate (LST)

One method tested for the removal of charcoal was to use Heavy Liquid to remove light

fractions of material from soil samples. Wood charcoal has a specific gravity (sg) or ratio of

density of 0.4sg, which enables it to float on water during archaeobotanical flotation techniques.

However, the microcharcoal observed in this experiment has instead settled in water during Step

Two of the methodology outlined here. It was hypothesised that this microcharcoal may be able

to be removed using a heavy liquid with a specific gravity heavier than water (1.0sg), but lighter

than the specific gravity of starch (1.7sg).

One archaeological sediment sample (Talasiu Spit 18) was selected to be sub-sampled

and processed to the point where Heavy Liquid in the form of lithium heteropolytungstate (LST)

was added using the methodology outlined below. Thirty millilitres of LST at 2.0sg was added

to the sample, and centrifuged at 1500rpm for 30mins. This was decanted through a 5µm

filtration mesh, enabling the LST to be separated from the extracted material and thus easily

recycled. The mesh was then placed in the top of a Falcon tube and de-ionised water was used

to wash the material caught on the mesh into the tube. All material lighter than 2.0sg and larger

than 5µm was therefore retained. Another LST solution at 1.2sg was then added, and the

process repeated so that a fraction that was lighter than 1.2sg was separated. The heavy fraction

was also retained as this should contain any starch residues.

The results of this experiment indicate that microcharcoal cannot be separated using

LST set at 1.2sg. Most of the charcoal examined tended to become waterlogged when exposed

to liquid over a sustained period of time, and became too dense to float. The differential specific

gravities of microcharcoals are probably a result of differing wood densities before charring,

particle size, and density as a result of water absorption. These changes probably occur either in

the soil or during Step One and Step Two.

Hydrogen peroxide (H2O2)

The second method tested in an attempt to remove charcoal from the archaeological sediments

was the addition of hydrogen peroxide or H2O2. Talasiu Spit 18 was again selected to be sub-

sampled for this experiment. The sample was processed until the point where it was reduced to

allow slide preparation. The sample was placed into a thin glass centrifuge tube under the fume

hood, and 10% hydrogen peroxide was added to the sample one drop at a time to gauge any

chemical reaction. There was no immediate reaction, nor to a higher percentage dilution of 30%

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added in the same manner. There was only a very small reduction in the amount of charcoal

observed within the sample.

The final test in this experiment involved the application of 30% hydrogen peroxide and

then the sample was placed in a beaker of water on a hotplate to stimulate a stronger chemical

reaction. The water was warmed to 30˚C, and the sample was observed for 1.5 hours within

which time there was still no reaction. A slide was prepared after the final test in this experiment

to observe any effects of these chemicals on starch morphology. It was clear that most starch

had either gelatinised or dissolved. Very low numbers of starch in native condition were

observed in this test sample.

Simple dispersal

The final method tested in this experiment was not to remove the charcoal, but to allow simple

dispersal within the sample. Rather than preparing only one or two slides from the reduced

samples after processing, three to four slides were constructed. This allowed any micro-charcoal

present in the samples to be dispersed over a larger number of slides, reducing the possibility of

these charcoal particles obscuring any starch granules present in the samples.

Conclusions

The use of chemical agents to remove microcharcoal from archaeological sediments was not

successful for a variety of reasons. Heavy Liquid separation using LST at 1.2sg was not able to

float off micro-charcoal, due to the varying densities of wood charcoal. Some microcharcoal

was removed during this process, but high concentrations remained in the heavy fraction that

also contained the extracted starch grains. Similarly, 10% and 30% hydrogen peroxide proved to

be ineffective in dissolving charcoal, even when heat was added in an attempt to produce a

stronger reaction. In addition, such concentrations of hydrogen peroxide affected starch

morphology and preservation, rendering the use of these chemicals unacceptable.

Experiment Three: Removal of supernatant and recycling of heavy liquid

A simple experiment was carried out during the first phase of laboratory processing of the

archaeological soil samples to allow the separation of the supernatant after heavy liquid in the

form of lithium heteropolytungstate (LST) was added. Current methodologies (Horrocks 2004;

Therin and Lentfer, in Torrence 2006b) either pipette or decant the supernatant into a separate

tube, leaving the heavy residue behind in the original centrifuge tube to either be kept for a

second phase of heavy liquid separation or to be discarded. Experimentation was conducted to

ease recycling of heavy liquid for use within other samples and reduce inter-sample

contamination.

During this experiment six samples from one spit (level) at Talasiu (TO-Mu-2) were

processed up to the stage prior to heavy liquid separation. Exactly 30ml of LST at 2.0sg was

added to all four of these samples within centrifuge tubes which were then placed into the

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centrifuge and spun at 1500rpm for 15mins. At this point two samples were chosen to attempt

pipetting off the supernatant, two samples were selected for decanting, and two samples were

chosen to test a new method which involved decanting the supernatant through a 5µm mesh

(Janelle Stevenson, pers.com). The reason for attempting this new method was to reduce the

amount of non-starch material within the sample after heavy liquid processing and to ease the

process of recycling the heavy liquid through separating the starch from the LST immediately.

Each set of samples were then processed accordingly. Individual techniques for separating the

supernatant were assessed for ease of use in terms of the time it took to carry out the separation,

the efficiency of the separation in terms of the amount of heavy residue within the supernatant,

and the subsequent steps needed to remove and recycle the heavy liquid.

Pipette Technique

Pipetting the supernatant off the top of the heavy residue which had sunk to the bottom of the

centrifuge tube proved to be a very efficient technique for separating the light and heavy

fractions. Very little of the heavy residue was accidentally added to the light fraction. However,

the method was also very time-consuming as only small amounts of the supernatant could be

removed at a time, taking around 5 minutes. The heavy liquid then needed to be removed from

the light fraction through various steps involving the dilution of the sample to wash the heavy

liquid and retain starch residues. The heavy liquid then needed to be passed through a glass

mesh to remove any contaminants. To increase the specific gravity of the heavy liquid, it was

put inside a glass beaker on a magnetic stirrer at low heat and monitored until enough water had

evaporated to return the LST to 2.0sg. This was again a time-consuming process, taking around

eight hours to enable the heavy liquid to be reused.

Decanting Technique

Decanting the supernatant into a new centrifuge tube took less time to separate the heavy and

light fractions—approximately 1 minute— but was less effective. There was some mixing of the

two fractions as the last of the supernatant was carefully poured into the second tube. This

meant that the final slides had more organic material than those made from the pipette samples.

The same process was then used to recycle the heavy liquid through dilution, sieving and

evaporating water to return the LST to 2.0sg.

Sieving Technique

Pouring the supernatant through the 5µm mesh was a time-consuming process as small amounts

of organic residue from the top of the heavy fraction was inter-mixed with the light fraction, as

seen within the decanting technique, and combined with charcoal to clog the mesh. A pump had

to be used to slowly allow the supernatant to pass through the mesh, taking around 10 minutes.

The light fraction remained on the 5µm mesh, and was then put into the top of a centrifuge tube

and washed off into the tube using de-ionised water. Only one wash was required to remove any

residual LST from the sample before the sample could be reduced for slide construction.

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Despite being more time-consuming in terms of separating the supernatant from the heavy

fraction, the technique was very effective at separating the heavy liquid from the light fraction

quickly without any dilution, enabling the LST to be used immediately after only one further

step of sieving through a glass filter paper.

Conclusions

Both pipetting and decanting the supernatant off from above the heavy fraction were more time-

effective methods than the sieving technique in terms of separating the light fraction for further

processing. Of these, pipetting was the most effective technique to reduce the amount of heavy

residue accidentally entering the light fraction during separation. Once these samples were

separated, both the pipette and decanted samples required further processing to remove the

heavy liquid and enable it to be re-used for subsequent samples. This processing added

approximately eight hours (dependent on the amount of heavy liquid being recycled) to the

laboratory protocol. In contrast, the sieved samples only involved one step of centrifuging and

decanting that took around four minutes, before the sample was ready to be reduced and placed

on a slide. The process of removing contaminants from the heavy liquid by filtering through a

glass mesh, and repeating this step added another five minutes to the protocol before the heavy

liquid was ready to be reused. Therefore, despite the initial processing time, the sieving

technique is the most time effective and efficient overall method for separating the supernatant

and recycling the heavy liquid.

Laboratory processing: Revised starch extraction protocol

After experimentation highlighted potential sources of starch contamination within the materials

used during standard starch extraction processes, a method for dispersing charcoal and a new

technique for removing the supernatant after density separation and recycling heavy liquid were

incorporated into a final extraction protocol. This protocol was based on modification of

techniques published by Horrocks (2004), Torrence (2006a, b) and Field (pers. comm. 2012). It

involved steps to sub-sample, deflocculate, settling, sieving, centrifuging, density separation,

and reduction of samples for slide construction.

Note on sub-sampling and site variation

Talasiu was the first site to be analysed for the presence of starch residues. A 3gm sub-sample

was taken from each 5cm spit excavated from the test-pit, and processed to extract preserved

starch residues. After radiocarbon dating revealed that all three sites represent relatively discrete

time periods, it became clear that there was little intra-site age variation and so few

chronological differences would be observed within each of these sites. A decision was made,

therefore, to sub-sample every second 5cm spit to gain a representative distribution of starch

preservation within the deposits sampled at Leka and Heketa.

Heketa had very low quantities of starch during the first round of analysis. As a result, a

decision was made to re-process four spits from the site with new sub-samples. A few changes

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were made in the processing technique to assess the potential of different variables in methods

for starch extraction. The samples were sieved through a 250µm filtration mesh, rather than

125µm. Secondly, the samples were placed in the centrifuge for 30 minutes rather than 15

minutes during heavy liquid separation. This gave a larger window of time for starch to release

from the heavy fraction and become part of the supernatant.

Laboratory protocol for starch extraction from archaeological sediments

Step 1: A 3gm representative sub-sample of each archaeological sample was measured

out and placed into a 50ml capacity Falcon centrifuge tube. Ten millilitres of filtered

5% Calgon mix was then added as a deflocculant to each of the tubes before the tubes

were capped and individually vortexed for 30 seconds.

Step 2: The samples in the tubes were poured into a glass beaker with 500ml of de-

ionised water and covered. Stokes Law was employed to calculate the amount of time

that the samples should be left to allow organic particles to settle. It was established that

samples should be left for at least three hours to allow the clay particles to separate, and

organic spherical particles larger than 5µm to settle 10cm at terminal velocity in water

at temperatures of 17-21˚C. After three hours each sample was decanted, refilled with

500ml de-ionised water and covered. These processes were repeated at least twice or

until the supernatant was clear.

Step 3: The sample was then poured through a 125µm sieve to remove the larger

organic fraction.

Step 4: The remaining sample was poured into a Falcon tube and capped, before being

centrifuged at 2000rpm for four minutes and then decanted. This process was repeated

until the supernatant was visibly clear.

Step 5: As much liquid was removed at this point and then 30ml of heavy liquid in the

form of lithium heteropolytungstate (LST) at 2.0sg was added to each sample. The

samples were then again put back into the centrifuge and spun at 1500rpm for 15

minutes.

Step 6: Each sample was decanted through a new 5µm mesh circle, enabling the LST to

be separated from the extracted material and thus easily recycled. The mesh was then

placed in the top of a Falcon tube and de-ionised water was used to wash the material

caught on the mesh into the tube. All material larger than 5µm was therefore retained.

Step 7: The samples were then centrifuged at 2000rpm for four minutes and decanted.

This process was repeated twice to wash and dispose of any remaining LST.

Step 8: The final step involved reducing the samples to less than 5ml by allowing the

samples to settle overnight and then pipetting off the supernatant. This remaining

material was placed onto slides and allowed to dry before Glycerol was added. The

material on the slide was gently agitated to release the dried starch residues from the

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glass, and then a cover-slip was placed over it and sealed with nail polish to ensure that

the slide was protected from contamination.

Light Microscopy

All samples of extracted starch residues from Talasiu, Heketa and Leka were observed and

imaged using light microscopy. A Leica DM6000 Compound Transmitted Light Microscope

within the Centre for Advanced Microscopy at the ANU was used to view starch in both

brightfield and cross-polarised light. Each slide was viewed in horizontal transects, enabling all

starch to be observed and eliminating the prospect of accidentally recording the same grain

twice. Images were taken of every starch grain encountered, with quantification capped at 100

grains per sample. These 100 grains were usually counted over several slides from a particular

sample, meaning no sampling technique was employed. Often the samples contained less than

100 grains in which case absolute counts were recorded. Images were taken in both brightfield

and cross-polarised light to enable recording of attributes related to the size and shape of the

grain, and also the extinction cross which can only be viewed in cross-polarised light. Each

imaged grain was given a number which correlated with the file names for any digital

photographs taken of that grain. The grains were rolled by tapping the top of the cover-slip

gently to enable accurate description of the three dimensional shape. This technique also

allowed the observer to note if the grain was lenticular or biconvex in one plane of view.

Archaeological starch classification: Assemblage-typology approach

To explore morphological patterning in the archaeological starch assemblage, a number of

starch morphotypes were created based on a combination of the nominal and metric attributes.

This analytical technique has been used elsewhere as a means of gauging morphological

variation within archaeological assemblages (Barton 2005; Crowther 2009:150-2; Lentfer et al.

2002; Mercader et al. 2008). The technique is most often used where a comprehensive

comparative collection is not available and therefore the ‘rules’ of group membership are not

clear (Crowther 2009:150). Breaking down the archaeological assemblage into ‘types’ enabled

the range of morphological diversity within each context to be studied, and provide an estimate

of the number of taxa present. This approach was also useful to identify starch that had been

modified through various cultural and natural taphonomic processes, using the work of Barton

(2009), del. P. Babot (2003:69-82) and Crowther (2009:19-61, 2012). The primary

morphological variable used in this study was three-dimensional shape, followed by shape

modifiers such as the number and type of pressure faceting, and the presence and type of

fissuring at the hilum.

Pinpointing the species from which these starch types could have originated was a

critical next step. To do this the morphotypes were compared to those observed within the

comparative collection. This was done by analysis of the morphological patterning recorded

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within the Excel database, and images taken during light microscopy and SEM. Most often, a

number of matches were possible. To narrow this list down further, the archaeological starch

types were then compared to the length and width ranges of the matches. This assemblage-based

approach can also highlight the possibility that archaeological starch does not originate from

any taxa in the comparative collection, and therefore may only be identified to genus or family

level, or remain as an unknown morphotype.

Archaeological starch classification: Multivariate statistical analysis

After the assemblage typologies had been created and some basic taxonomic identifications

were given to the extracted archaeological starch based on visual or size characteristics,

multivariate statistical analysis was carried out to further extrapolate or confirm these

identifications. The extracted archaeological starch was classified using multivariate statistical

analysis in the form of Linear Discriminant Function Analysis (DFA). The statistical analysis

was based on the analysis of the reference material, and was used to classify archaeological

starch using the same variables. These were classified in the same manner as the reference

starch, but as ‘ungrouped specimens’ that were not included in the learning parameters for the

DFA.

The database for each test-pit from each site was divided into two based on the

orientation ratios, and the range of variables altered according to those assessed and deemed to

be significant from the analysis of the comparative collection. Instead of being given a

‘grouping’ as within the datasets from the comparative collection, a ‘?’ was entered into this

column for each archaeological starch grain. Each archaeological starch grain was named in the

‘point’ column according to the spit from which they were extracted, and the grain number

given to them during recording. In this way, each archaeological dataset could be individually

compared to one of the two datasets (side-on or end-on) from the comparative collection, and

each starch grain given a predicted classification alongside the reference starch. These were

given through the ‘classifier’ output for each dataset, and each starch grain could be traced back

to the sample from which it was extracted through the name it was given in the point column.

Quantification of the classifications was carried out so that the number of starch grains

matched to each species within a particular sample could be calculated. These figures gave an

overview of the range of species potentially present within each sample and the quantities of

starch classified within these groupings. During this phase, the results of classifications from

both datasets were combined; however, it became clear that in order to do this some system was

needed to filter the classifications, creating a statistical gauge for the level of confidence in the

presence of any species within a sample.

Confidence in these classifications in a particular sample was made by fulfilling a

number of criteria. High confidence classifications had to have a successful reclassification rate

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within DFA for that species of over 60%, and more than five grains had been matched to that

species within that sample. Moderate confidence classifications had to either have over 60%

correct reclassification but less than five grains matched, or less than 60% correct

reclassification and over five grains matched to that species within that sample. Low confidence

classifications were given when the reclassification for that species was less than 60%, and less

than five grains were matched to that species. In this way, each classification made using DFA

was acknowledged, but a means of gauging the actual likelihood of that species being present in

a particular spit was also provided. The identifications were then confirmed using visual

checking of the images of the archaeological starch. These were compared with the images of

the species taken using light microscopy and SEM to which the DFA had classified each grain,

confirming or eliminating these as possible taxonomic classifications.

Macrobotanical analysis: Charred parenchyma and endocarp

Laboratory analysis

Macrobotanical remains were collected using three different methods during the excavation

process. Any large charcoal fragments above 1cm in diameter observed during excavation of the

test units were collected and placed in aluminium foil envelopes. These samples were labelled

according to the site, test unit and spit from which they derived. Charcoal and seeds were also

collected within both the light and heavy fractions during flotation. The light fraction floated

during bucket flotation when water was added to the soil, and the heavy fraction remained in the

bottom of the bucket to be wet-sieved. Some charcoal can become water-logged and therefore

sinks during this process. This depends on the degree of charring within the fragments, and

porosity of the material.

In the quarantine laboratory at the ANU, the heavy fraction was sieved through a 3mm

mesh to create two size fractions, smaller and larger than 3mm. These fractions were then sorted

into material and artefact types including shell, ceramics, land snails, seeds, and charcoal. These

were bagged separately and labelled according to the site, test pit, spit and sample type (in situ,

flot or wet-sieved). The flot (light fraction) was likewise sorted into material types such as

charcoal, seeds, insect remains, pumice, small bone and landsnails. The charcoal from each of

these sources, including in-situ, was then further sorted into parenchyma, wood charcoal and

endocarp.

Charred endocarp

Where possible the endocarp was identified to genus or species level. This taxonomic

identification was carried out first through the observation of surface morphology and features,

and second through fracturing endocarp fragments down the radial section, and viewing the cell

arrangement. Coconut (Cocos nucifera) has a distinctive surface texture on both the exterior and

interior surfaces of the endocarp. This texture is created by a cell arrangement that creates a

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‘cross-hatched’ effect through long, thin parenchyma cells that stack horizontally and vertically

alternately. Candlenut (Aleurites moluccana) is identifiable through distinctive surface

morphology. The exterior surface of the endocarp has a bumpy and slightly warped texture

similar to a walnut, and a high degree of curvature relative to fragment size.

Parenchyma

Parenchyma was identified to taxonomic level using the range of morphological features

recorded within the comparative collection. Each fragment tentatively identified as

parenchymatous was firstly described in terms of general and surface morphology (Hather

2000), and then fractured along the transverse and longitudinal planes to record cell

arrangement and bundling features. The fractured parenchyma was placed into a small Petri dish

and nestled in a bed of salt, and an Olympus Compound light microscope was used to view and

image the fragments in reflected light. These fragments were confirmed as parenchyma based

on morphology which differs from wood charcoal. These morphological traits include a more

rounded surface due to the exposure and erosion of cells; surface features such as buds,

detachment scars and spines; few visible rays and thus a more uneven fracture; consistent cell

shapes that are usually rounded or angular; and the presence of distinctive vascular bundles or

tissues.

Each fragment was identified as either stem or root-derived vegetative parenchyma, and

then to species of origin where possible. The identification flowchart key was utilised to provide

either a single identification or a list of possible identifications where no further breakdown of

the taxa is possible due to morphological overlap, or other features of the archaeological

parenchyma are not visible. These taxonomic identifications were then confirmed using images

from both light microscopy and SEM. The images could also be utilised to eliminate or confirm

taxa where a list of possible identifications is provided.

Classifications were then given based on the determination system outlined in Chapter 5

using identification criteria and associated levels of confidence compiled by Paz (2001) and by

Oliveira (2008). This determination system has been used successfully by these researchers in

the past to analyse macrobotanical plant remains from a range of archaeological contexts in the

Asia-Pacific region (Barker et al. 2011; Barton and Paz 2007; Oliveira 2008; Paz 2001, 2005).

The identification key is useful as a means of breaking down the morphology in the comparative

collection. However, there was a reasonable likelihood that some samples would not match any

of the specimens within the comparative collection due to both the condition of fragments and

also the fact that the reference collection is not exhaustive. The reference collection also has a

general focus on economic and non-economic plant taxa from Western Polynesia, and so would

require the inclusion of additional specimens for use in other geographic locations.

138

Chapter 8 Results

Presentation of results is divided into four main sections. The first section considers the

quantification and identification of macrobotanical remains from all test units and sites. The

various extraction techniques utilised in the field is also compared in terms of the effectiveness

of the recovery of charred endocarp, wood charcoal and parenchyma. Each site will also be

compared in terms of the quantities of identified material, the distribution of these in test units

and the results of a case study presented for the identification of parenchyma at Talasiu. The

second section focuses on the quantification and identification of microbotanical remains in the

form of starch grains. Once again each site is compared in terms of starch preservation, the

numbers of identified species and the distribution of starch within test units according to dated

cultural deposits. The third section analyses a number of Western Pacific plant production

systems using theoretical insights from Evolutionary and Human Ecology for assessing

efficiency of yield and associated nutritional returns. These modern examples provide a useful

range of models within which the past systems, represented by archaeobotanical remains, can be

assessed and placed in the final section of this chapter.

Macrobotanical analysis

Quantification of charcoal

Macrobotanical assemblage breakdown

Overall, macrobotanical preservation within all of the sites and test units was relatively good,

with small quantities of a range of plant material recovered. However, these remains only

composed up to 0.46% of the total pre-processing material weights removed from these units

(including soil, shell and other matrices). Within these assemblages, the largest quantities of

macrobotanical material were recovered from Talasiu TP2, with a total weight of 60.8g. The

smallest assemblage was recovered from Leka TP3, however only three spits were processed

from this test unit.

The quantification of the macrobotanical assemblage was primarily based on the

separation and analysis of three main components: coconut, other endocarp, and wood charcoal,

from which vegetative storage parenchyma was separated later. Wood charcoal composed the

bulk of the macrobotanical assemblages from almost all the test units at Talasiu (TO-Mu-2),

Leka (J17) and the Heketa (TO-Nt-2), making up around 78% of the collective weight (see

Table 8.1 and Figure 8.1). Only Leka TP4 varied from this trend, with wood charcoal making up

only 26% of the macrobotanical assemblage from this test unit. In particular, Talasiu TP2 had

the greatest amount and distribution of non-endocarp charcoal (53.4g). For this reason, this test

unit was selected as a case study for the separation and identification of vegetative storage

parenchyma. Only very small quantities of parenchyma (<1g) were found in any given sampled

deposit. Aside from wood charcoal, non-coconut endocarp was the second most common

139

macrobotanical material recovered and quantified, composing around 17% of the total

assemblage. Coconut endocarp was recovered from every test unit, but only in small quantities

and so made up only 5.8% of the overall assemblage.

The quantification of macrobotanical materials is analysed here in terms of the rates of

recovery from flotation, wet-sieving and in situ collection, and the overall quantities, as well as

the distribution of these quantities within each test unit. This quantification indicated both the

success of various methods for extraction of particular plant remains, as well as the effects of

site taphonomy and formation processes upon archaeobotanical assemblage composition.

Table 8.1 Summary of total macrobotanical assemblages from all sites and test-pits

Figure 8.1 Composition of overall macrobotanical assemblage in terms of abundance

Coconut endocarp

Basic sorting processes highlighted an interesting pattern in the macrobotanical extraction

process. Coconut endocarp was extracted exclusively during the wet-sieving stage of

archaeobotanical processing in the field. This is most likely because of the higher density of

coconut endocarp, which does not float as well as wood charcoal, or other varieties of endocarp.

Another possibility is that coconut endocarp does not disaggregate easily from clay soils during

the initial deflocculation process before flotation. No experimental tests were carried out to test

either of these ideas. These coconut endocarp fractions were separated primarily to enable

selection of samples for AMS dating.

When all of the test units are compared directly, the highest quantities of coconut

endocarp were observed within Talasiu TP2 and Heketa TP3 with a total of 1.6g in each test

unit. However, when these quantities are considered as a fraction of the total macrobotanical

weight for each test unit, the highest percentages were extracted from Leka TP3 (10.7%) and

TP4 (19.5%) (see Table 8.2). The remaining test units contained coconut endocarp fractions that

Botanical material Talasiu Leka TP2 Leka TP3 Leka TP4 Heketa TP2 Heketa TP3 Total (g) % of assemblage

Coconut (g) 1.6 0.6 0.1 0.7 1.6 1.2 5.8 4.832125302

Endocarp (g) 5.8 0.3 2.3 4.1 2.6 5.1 20.2 16.82912605

Wood charcoal/parenchyma (g) 53.37 8.47 2.4 1.72 4 24.07 94.03 78.33874865

Total (g) 60.77 9.37 4.8 6.52 8.2 30.37 120.03

% of total material weight 0.0219 0.0064 0.0065 0.0696 0.1708 0.4658

140

were less than 10% of the entire macrobotanical weight, with Leka TP3 containing the smallest

percentage.

Recovered coconut endocarp was distributed throughout the test unit from Talasiu, with

quantities found in every stratigraphic layer, aside from the sterile clay at the base, and almost

every spit. Only one stratigraphic layer was processed in TP2 from Leka. This layer was Layer

8, which was a mid-brown silty clay cultural layer with charcoal, and this contained coconut

endocarp in the bottom 20cm (105-125cm below surface) before sterile clay was encountered.

Leka TP3 only contained coconut endocarp in this same cultural layer in the top 5cm (90-

95cmbs). In contrast, coconut endocarp was extracted from all sampled stratigraphic layers in

Leka TP4 (Layers 4-6), but not every spit in these. Small quantities were recovered from the

lower 15cm (110-125cmbs) of Layer 4, a mid-brown silty clay layer similar to that observed in

TP2 and TP3, and the top 5cm (125-130cmbs) and middle (134-140cmbs) of Layer 5 in a more

dense shell deposit. Coconut endocarp was also recovered from the bottom 10cm (155-

170cmbs) of this test unit in the mixed clay and shell deposit of Layer 6. At Heketa, coconut

was extracted from all stratigraphic layers in TP2, but was not observed within the bottom 10cm

of this test unit (90-100cmbs). Coconut endocarp extracted from TP3 was mostly concentrated

in the lower 35cm (70-105cmbs) of this test unit, in the base of Layer 3 and throughout Layers

4-5.

Table 8.2 Quantification of coconut endocarp from all sites and test-pits

Other endocarp

Both wood charcoal and non-coconut endocarp composed a large percentage of the

macrobotanical remains from all sites and test units. Endocarp was successfully extracted using

all three archaeobotanical techniques employed during fieldwork. Wet-sieving and in situ

collection resulted in the extraction of endocarp from all test-units, whilst flotation had more

variable rates of recovery. This could be the result of issues with the flotation of endocarp

already highlighted with regard to coconut endocarp extraction. This fraction was separated as a

preliminary step towards the selection of samples for AMS dating. These endocarp fractions

remain unidentified because of the lack of a comprehensive comparative collection. Some

Aleurites moluccana was observed but was not separated from other endocarp due to a focus

within this study on the identification of parenchyma within the macrobotanical remains.

Site TP Wet-sieved (g) In-situ (g) Flot (g) Total % of total macrobotanical weight

Talasiu 2 1.6 0 0 1.6 2.6

Leka 2 0.6 0 0 0.6 6.4

Leka 3 0.1 0 0 0.1 2.1

Leka 4 0.7 0 0 0.7 10.7

Heketa 2 1.6 0 0 1.6 19.5

Heketa 3 1.2 0 0 1.2 4.0

Total 5.8 0 0 5.8 45.3

141

The quantification of other endocarp followed the same pattern as coconut endocarp,

whereby the highest quantities were extracted from Talasiu TP2 (5.8g) and Heketa TP3 (5.1g)

(see Table 8.3). When quantities of endocarp are considered as percentages of the total weight

of macrobotanical material extracted from these test units, Leka TP4 clearly has the highest

percentage of other endocarp (62.9%), while Leka TP2 has the lowest (3.2%) by a significant

margin.

Talasiu test unit TP2 again has recovered endocarp distributed throughout all strata.

Only two spits did not contain any non-coconut endocarp, at 0-5cmbs and 80-85cmbs. The three

test units at Leka have variable distributions of endocarp throughout the observed stratigraphic

layers. Endocarp was recovered from the top (90-95cmbs), middle (105-110cmbs) and bottom

(120-125cmbs) spits of Layer 5 in TP2. In contrast, TP3 had non-coconut endocarp in all three

sampled spits of the same stratigraphic layer, while TP4 had small quantities of endocarp

throughout the test unit apart from the top 5cm (95-100cmbs). Non-coconut endocarp was found

throughout all strata within TP2 and TP3 at Heketa, but was absent from the bottom 5cm (100-

105cmbs) of TP3.

Table 8.3 Quantification of other endocarp from all test units

Wood charcoal and parenchyma

The separation of monocot and dicot wood and parenchymatous charcoal from coconut and

other endocarp was the final stage in the quantification of macrobotanical material. Because of

the similarity of vegetative storage parenchyma to wood charcoal, any plant-derived charred

material that was not endocarp was separated first and weighed as a single fraction. Because of

the abundance of charcoal from Talasiu TP2, this unit was used as a test for identifiable

parenchymatous material. Wet-sieving and flotation techniques were by far the most successful

method for recovering both wood charcoal and parenchyma. The vesicular cellular structure and

specific gravity of wood charcoal enables this material to float relatively easily in water, a fact

which has been utilised by archaeobotanists for many years. The success of wet-sieving, as a

follow-up to flotation steps, is most likely the result of the inability of technicians to easily

deflocculate clay sediments to release wood charcoal in the field using bucket flotation methods.

The highest quantities of wood charcoal (including parenchyma) were recovered from

test unit TP2 at Talasiu with a total of 53.4g (see Table 8.4). TP3 at Heketa had the second

greatest quantity (24.1g) of wood charcoal, while the remaining test units all had less than 10g.

Spit TP Wet-sieved (g) In-situ (g) Flot (g) Total % of total macrobotanical weight

Talasiu 2 3.6 0.9 1.3 5.8 9.5

Leka 2 0.2 0.1 0 0.3 3.2

Leka 3 0.6 1.4 0.3 2.3 47.9

Leka 4 2.4 1.7 0 4.1 62.9

Heketa 2 1.6 0.3 0.7 2.6 31.7

Heketa 3 3.9 0.7 0.5 5.1 16.8

Total 12.3 5.1 2.8 20.2 172.0

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Despite these figures, when these quantities are viewed as percentages of the whole

macrobotanical assemblages from each of these test units, Leka TP2 has the highest percentage

of wood charcoal, with 90.4%. These statistics indicate that the assemblages from Talasiu TP2,

Leka TP2 and TP3, and Heketa TP3 are all dominated by wood charcoal. In contrast only 26.4%

of recovered charcoal is represented by wood charcoal in Leka TP4, while Heketa TP3 has just

under half (48.8%).

The distribution of these quantities within the test units from the sites of Talasiu, Leka

and Heketa are variable; however, at least small amounts of wood charcoal were present in

every spit and stratigraphic layer sampled. In Talasiu TP2, most charcoal was concentrated

around Layer 3 (40-75cm) where it is likely that larger fragments were preserved in the matrix

of loose shell and yellow red clay. Very little charcoal was recovered from Layers 1, 2 and 5 in

the more compact shell midden deposits. Leka TP2, TP3 and TP4, and Heketa TP2 had

relatively even distribution of wood charcoal in the test units, with small amounts (<2g) in every

spit and stratigraphic layer. In contrast, Heketa TP3 had the largest concentration of charcoal

within Layer 4 (80-90cmbs) with 12.5g, while the remaining strata had less than 5g.

Table 8.4 Quantification of wood charcoal and parenchyma from all test units

Parenchyma distribution and identification: Talasiu TP2 case study

Within this section the macrobotanical assemblage from test unit TP2 at Talasiu (TO-Mu-2) was

chosen to conduct a case study for the separation and identification of vegetative storage

parenchyma. Due to the documented difficulty of separating these charred remains from wood

charcoal (Hather 2000), it was decided to analyse only one of the six test units excavated during

the 2011 field season. Talasiu TP2 was chosen for the abundance of charcoal in the

macrobotanical assemblage of this unit, on the assumption that the preservation of any

vegetative storage parenchyma was likely to be the greatest.

Parenchyma was first separated from wood charcoal based on ground tissue

morphology, such as consistent cell shapes that are usually rounded or angular; the presence of

distinctive vascular bundles or tissues, usually with very few rays dividing these tissues. This

initial step enabled the presence of vegetative and non-vegetative parenchyma (i.e. fruits) in

samples to be recorded. The distribution of these remains in the test unit varied, although at least

one fragment of charred parenchyma was extracted from each stratigraphic layer. The disturbed

Spit TP Wet-sieved (g) In-situ (g) Flot (g) Total % of total macrobotanical weight

Talasiu 2 23.7 17.9 11.8 53.4 87.8

Leka 2 3.5 4.5 0.5 8.5 90.4

Leka 3 0.8 1.6 0.0 2.4 50.0

Leka 4 1.0 0.3 0.5 1.7 26.4

Heketa 2 2.0 1.1 0.9 4.0 48.8

Heketa 3 22.4 1.2 0.5 24.1 79.3

Total 53.4 26.6 14.1 94.0 382.6

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midden within Layer 1, and very compact shell midden deposit in Layer 2 both contained three

fragments. The largest overall quantity of parenchyma was recovered from the loose large shell

matrix composing Layer 3 (see Table 8.5), with a total of five fragments. Layer 4 below this

contained another two fragments, while the basal cultural layer of reddish clay and small

crushed shell only contained one fragment.

Each fragment was identified to species where possible, using a range of attributes of

ground tissue and vascular tissue morphology, and the identification flowchart key created for

the reference collection (Chapter 5). Most fragments could be identified with a moderate degree

of confidence, and were therefore labelled with the prefix ‘cf.’, indicating that most

morphological features matched the written descriptions and resembled the reference SEM

images.

A number of different families are represented within the identified parenchyma

assemblage. These included Araceae, Dioscoreaceae, Moraceae, Musaceae, and Zingiberaceae.

Four fragments were identified as cf. Colocasia esculenta, or the common taro and were

extracted from Layers 2 and 3 to a maximum depth of 65cmbs. Two species belonging to the

Dioscorea or yam genus, Dioscorea alata and Dioscorea nummularia, were found in Layers 3

and 4, with a total of four identified fragments. A single fragment identified as cf. Artocarpus

altilis (breadfruit) fruit/flesh was found in Layer 2 between 25-30cmbs. Interestingly, a single

fragment of parenchyma from Layer 3 was identified as belonging to the Musaceae family,

indicating that the flesh of this fruit was either intentionally cooked or discarded into a fire and

incorporated into the ash. Members of the Ginger family Zingiberaceae, such as Zingiber

zerumbet or Curcuma longa were often cultivated and eaten in Tonga or used for medicinal and

ornamental purposes. The antiquity of this use is demonstrated by the recovery of parenchyma

identified confidently to this family within the archaeobotanical record at Talasiu. The

remaining fragments could only be identified as ‘root-derived’ (Layer 3), or were left classified

as ‘unidentifiable’ (Layers 1 and 5).

144

Table 8.5 Distribution and identification of parenchyma extracted from Talasiu TP2

Microbotanical analysis

Extraction, quantification and distribution

Microbotanical assemblage breakdown

Starch was successfully extracted from all test units sampled for microbotanical remains from

Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2). Due to time constraints, only four of the

six excavated test units were sampled, with a total of 39 bulk soil samples processed. These test

units included Talasiu TP2, Leka TP2 and TP4, and Heketa TP3, and were chosen based on site

taphonomy and the likelihood of microbotanical preservation. Of these, Talasiu TP2 contained

the largest quantity (count) of starch grains, but this is biased by the large number of samples

analysed from this site. Every spit or level was sampled from Talasiu TP2, whilst every second

spit was sampled from the remaining test units. This alteration of the microbotanical

subsampling procedure was made after Talasiu TP2 was completely processed, and counts

revealed that there was very little variation in starch distribution within the test unit apart from a

spike at the very base of the cultural deposits. Due to time constraints, it was deemed

appropriate to process every second sample and halve the overall processing time.

With this in mind, it may be appropriate to compare the quantities of starch from each

of the test units as an average based on the number of processed samples (see Table 8.6). When

these figures are calculated, it becomes clear that Leka TP2 had the highest quantity of starch

per sample, with an average of 93 grains. Leka TP3 followed with an average of 31.4 grains per

Depth Spit Layer Parenchyma Identification

0-5 1 1

5-10 2 1

10-15 3 1 x

Unidentifiable

Zingiberaceae

15-20 4 1 x Zingiberaceae

20-25 5 2 x cf. Colocasia esculenta

25-30 6 2 x cf. Artocarpus altilis fruit


35-40 8 3

40-45 9 3 x

cf. Dioscorea alata

cf. Musaceae


50-55 11 3 x cf. Dioscorea alata

55-60 12 3 x Root-derived


65-70 14 4

70-75 15 4 x cf. Dioscorea alata

75-80 16 4 x cf. Dioscorea nummularia

80-85 17 5

85-90 18 5 x Unidentifiable

90-95 19 5

95-100 Control 6

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sample, just slightly higher than Talasiu TP2 which contained an average of 22.5 grains per

sample. The lowest average derived from TP3 at Heketa (9 grains). Considering that AMS

dating indicates that this site was the most recently occupied, these figures would indicate that

either plant food was not being processed or discarded in these cultural deposits at Heketa, or

that taphonomic factors such as soil pH levels or enzymatic activity heavily impacted starch

preservation. These quantities from each test unit will be briefly discussed with regard to the

distribution of starch throughout the sampled cultural deposits below.

Table 8.6 Overall quantities (counts) of starch extracted from all sampled test units at Talasiu (TO-Mu-2)

Talasiu (TO-Mu-2)

Test unit TP2 from Talasiu contained a total of 449 starch grains, extracted from 20 processed

3gm bulk soil samples (see Table 8.7). When this quantity is broken down into the distribution

of starch grains within each recorded stratigraphic layer, some patterning emerges. The

disturbed midden at the top of the test unit (0-20cmbs) which composes Layer 1 has a total of

107 starch grains from four samples. Layer 2 below this has the smallest quantity of starch

grains, with a total of 47 grains from three samples. Layer 3 has the largest number of samples

(n=6), however this deposit has a quantity of starch (96 grains) that falls in the middle of the

range when compared to the other strata. Layer 4 had the second smallest quantity of starch with

64 grains from three samples. Finally, Layer 5 at the base of the cultural deposits had the largest

quantity, with a total of 128 grains extracted from three samples. The control sample taken from

the sterile clay below the shell midden had seven starch grains, which most likely derived from

the transition between these two deposits.

Site Total samples analysed Total count Average/sample

Talasiu TP2 20 449 22.5

Leka TP2 4 372 93.0

Leka TP4 8 251 31.4

Heketa TP3 7 63 9.0

Totals 39 1135 29.1

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Table 8.7 Distribution of starch counts within Talasiu TP2

Leka (J17)

Two test units were sampled from excavations at Leka, TP2 and TP4. Leka TP3 was excluded

from this analysis as stratigraphic comparisons revealed that the cultural deposit sampled within

this test unit was already sampled in TP2. TP2 had a total starch count of 372 starch grains

extracted from four 3gm bulk soil samples. These were distributed relatively evenly throughout

the test unit, which seems reasonable considering these four samples were taken from the same

stratigraphic layer (Layer 7) (see Table 8.8). Slightly fewer starch grains were recovered in the

lower 10cm of the unit, above the sterile clay. This is most likely a result of sampling as these

figures are not significantly different from the samples above, especially when considered in

comparison with other samples from other test units.

Table 8.8 Distribution of starch counts within Leka TP2

Leka TP4 had a different starch distribution pattern. Most starch was located in Layer 4

in two samples from 95-110cmbs, where the 100 grain maximum count was reached for both

samples. Layer 4 is possibly the same as Layer 7 in TP2, but the distance between these two

units makes this correlation difficult to prove. However, this would explain the high quantity of

Depth Spit Layer Starch count

0-5 1 1 11

5-10 2 1 19

10-15 3 1 34

15-20 4 1 43

20-25 5 2 11

25-30 6 2 11

30-35 7 2 25

35-40 8 3 14

40-45 9 3 5

45-50 10 3 20

50-55 11 3 6

55-60 12 3 46

60-65 13 3 5

65-70 14 4 16

70-75 15 4 10

75-80 16 4 38

80-85 17 5 18

85-90 18 5 24

90-95 19 5 86

95-100 Control 6 7

Totals 449


90-95 1 7 102

100-105 3 7 100

110-115 5 7 82

120-125 7 7 88

Totals 372

147

starch extracted from these deposits, especially in comparison with other deposits in TP4.

Below Layer 4, starch quantities drop off significantly in Layers 5-6. Layer 5 has a total of 30

starch grains from three samples, while Layer 6 only has five grains from two samples.

Table 8.9 Distribution of starch counts within Leka TP4

Heketa (TO-Nt-2)

Only one test unit from Heketa was sampled for microbotanical remains. A decision was made

to sample TP3, and leave TP2 due to both time constraints, and the fact that stratigraphic

comparison indicated that the deposit sampled in TP2 (Layer 4) was most likely the same as

Layer 3 in TP3. As mentioned earlier, TP3 had the smallest amount of extracted starch with a

total of 63 starch grains from seven samples. Similar to Leka TP3, the highest quantity of starch

was extracted from the uppermost layer, Layer 3, with 43 grains recorded (see Table 8.10).

Below this, Layer 4 had 11 grains extracted from two samples, while Layer 5 had only seven

grains. Layer 5 is an ash lens within Layer 4, and this could explain the low quantity in this

sample.

Table 8.10 Distribution of starch counts within Heketa TP3

Identification: Assemblage-typology approach

As Talasiu TP2 was the first test unit to be processed for starch and classified using multivariate

statistics in the form of Linear Discriminant Function Analysis, this unit was utilised as a case

study. The assemblage-typology approach was compared with the DFA classifications, followed

by visual checking of starch grains. All of the extracted archaeological starch was recorded

using the same morphological attributes as the comparative collection and entered into an Excel


95-100 1 4 100

105-110 3 4 100

115-120 5 4 16

125-130 7 5 9

135-140 9 5 16

145-150 11 5 5

155-160 13 6 5

165-170 15 6 0

Totals 251


40-45 1 3 25

50-55 3 3 9

60-65 5 3 2

70-75 7 3 7

80-85 9 4 9

90-95 11 5 7

100-105 13 4 4

Totals 63

148

database. Once this was complete, it was important to establish what morphological patterning

could be seen within the assemblage. Therefore, a number of starch types were created that were

based on a combination of the recorded nominal attributes. The primary variable used was

shape, and then further attributes such as the number and type of pressure faceting, and the

presence and type of fissuring at the hilum. The abundance of these starch types in the

assemblage from Talasiu TP2 was calculated. However, as we still do not fully understand

factors affecting starch production with plant organs and starch preservation in sediments,

quantification may not be the best analytical technique to use here. Simple presence or absence

was deemed to be more appropriate and was used for further analysis.

In order to establish the identity of starch types they were compared to those grains in

the comparative collection. Most often, a number of possible matches were made. To narrow

this down further, the archaeological starch types were compared to the length range of the

matches. For example, Type 1 or cone-shaped grains, were present in the yams Dioscorea alata,

Dioscorea bulbifera, Dioscorea rotundata and Dioscorea nummularia. It is possible to rule out

D. rotundata based on length, and probably also D. nummularia (see Figure 8.2). Therefore this

starch type most likely originated from D. alata or D. bulbifera, but it is probably most

appropriate to keep this identification at family level at this stage (see Table 8.11).

149

Figure 8.2 Box plot demonstrating maximum length comparison of archaeological starch Type 1 with

Dioscorea spp.

Table 8.11 Table outlining suggested family of origin of archaeological starch types from Talasiu TP2.

This preliminary starch identification suggests that the Talasiu assemblage contains

starch from Dioscoreaceae, Musaceae and from the Araceae or aroid family, in this case most

likely originates from Cyrtosperma merkusii or the giant swamp taro, and Amorphophallus

paeoniifolius, the giant stink lily, rather than Colocasia esculenta or the common taro.

Interestingly, comparison of these archaeological starch grains with reference specimens not

150

expected to be present within the time period represented by the deposits at Talasiu tentatively

identified some of the starch as possibly originating from the Convolvulaceae family to which

Ipomoea batatas or sweet potato belongs. Clearly, this species should not be in the assemblage

as I. batatas is thought to be a late prehistoric or historic introduction into Tonga (Fall 2010;

Kirch 1978, 1990), and so is either contamination or a misidentification. Later multivariate

statistics and visual checking ruled out the identification of I. batatas for Talasiu TP2. The

distribution of identifications suggested by the assemblage- typology approach is outlined in

Table 8.12.

The assemblage-typology approach suggests some basic family-level identifications of

archaeological starch from Talasiu TP2. However, the use of multivariate statistics in the form

of Discriminant Function Analysis enabled these identifications to be more confidently

narrowed to species for a larger number of extracted grains. In light of the more accurate

species-level data provided by multivariate statistical analysis, assemblage-typology analysis

was not applied to the rest of the sites and test units from Leka (J17) and Heketa (TO-Nt-2). For

the multivariate statistics, a comprehensive reference collection was available containing both

nominal and metric data with light microscope and SEM imagery, enabling the comparison of

reference material data with that from extracted archaeological starch.

Table 8.12 Distribution of preliminary identifications within Talasiu TP2 using the assemblage-typology

approach

Identification: Multivariate statistics—Discriminant Function Analysis

Linear Discriminant Function Analysis (DFA) within the PAST statistical software package was

utilised as part of a multivariate statistical approach to the identification of archaeological starch

Layer Spit Depth Dioscorea sp. Musaceae Araceae

1 1 0-5cm •

1 2 5-10cm •

1 3 10-15cm •

1 4 15-20cm • •

2 5 20-25cm • •

2 6 25-30cm •

2 7 30-35cm • •

3 8 35-40cm •

3 9 40-45cm

3 10 45-50cm • •

3 11 50-55cm

3 12 55-60cm •

3 13 60-65cm

4 14 65-70cm •

4 15 70-75cm •

4 16 75-80cm •

5 17 80-85cm •

5 18 85-90cm • •

5 19 90-95cm • • •

6 Control 95-100cm

151

grains. The methods for applying this technique within the reference collection to assess the

morphological diversity of Pacific cultigens (Chapters 3-5), and how this statistical analysis

would enable the classification of archaeological starch with varying degrees of confidence

(Chapter 8) have already been explained. The results of this analysis will be presented here,

along with the steps taken to create a species list of high confidence for each of the three sites

under analysis.

Starch classifications were made using the same algorithms developed for the reference

collection, and were assessed with varying degrees of confidence based on the species-level

data. In order to interpret archaeological classifications each sample was analysed according to

the number of starch grains classified to each species, and the percentage of correct

reclassifications of that species when the reference collection comparison stage had been carried

out (Chapter 5). To reiterate, these criteria were:

High confidence classifications had to have a successful reclassification rate within

DFA for that species of over 60%, and more than five grains had been matched to that

species within that sample.

Moderate confidence classifications had to either have over 60% correct reclassification

but less than five grains matched, or less than 60% correct reclassification and over five

grains matched to that species within that sample.

Low confidence classifications were given when the reclassification for that species was

less than 60%, and less than five grains were matched to that species.

The database of archaeological starch extracted from each sample (spit) was divided

into two based on the orientation of each starch grain (eccentric/side on or centric/end-on).

These were compared to the two datasets created for the reference collection. The outputs of the

DFA produced a list of classifications, as well as Discriminant Analysis plots showing the

distribution of archaeological grains according to the first two canonical variates (see Figure 8.3

and Figure 8.4). These act as visual guides for inspection of Mahalanobis distances from group

centroids and ellipses (Baxter 2003) and Figure 8.3suggests that many of the archaeological

grains classified in the centric dataset may in fact belong to none of these groups. In contrast, in

Figure 8.4 the distribution of archaeological grains within the eccentric reference dataset more

often falls within the ellipses of these species, in some species more commonly than others.

Talasiu (TO-Mu-2)

All of the 449 starch grains extracted from 3g soil sub-samples from TP2 at Talasiu were

assigned to a species using DFA. When these classifications were tabulated according to sample

(spit) and level of confidence, it became clear that the archaeological starch grains were

assigned to most of the species within the reference collection with at least low level

confidence. The only species not apparently represented by archaeological starch were

152

Xanthosoma sagittifolium (modern taro introduction), Curcuma longa (turmeric) and Dioscorea

pentaphylla (five-leaved yam). Several species could be classified with high confidence within

the test unit. These included Colocasia esculenta (common taro), Inocarpus fagifer (Tahitian

chestnut), Musa sp.2 (banana), Piper methysticum (kava) although this could be considered a

contaminant, and Spondias dulcis (Otaheite apple). Some starch was also classified with low

level confidence to suspected historic or modern contaminants, including Ipomoea batatas

(sweet potato), which was probably a late prehistoric introduction and Solanum tuberosum

(white/Irish potato), which is a modern contaminant. These present problems for the dataset, but

visual checking of the starch classifications within the next stage of the analysis proved

successful in eliminating misclassifications from the final species lists.

Figure 8.3 Discriminant analysis plot for centric dataset showing ellipses (coloured dots represent reference

species, black dots represent archaeological grains)

153

Figure 8.4 Discriminant analysis plot for eccentric dataset showing ellipses (coloured dots represent reference

species, black dots represent archaeological grains)

Table 8.13 Levels of confidence from DFA classification of archaeological starch from Talasiu TP2. NB High

confidence (black), moderated confidence (medium grey) and low confidence (light grey)

Using visual checking techniques, many classifications were rejected, leaving a much

smaller final species list for Talasiu TP2. Some obvious misclassifications were also able to be

corrected using this step, and new classifications provided. Three aroids were represented after

visual assessment in this final list, including Amorphophallus paeoniifolius (elephant foot yam),

Colocasia esculenta, and Cyrtosperma merkusii (giant swamp taro), along with two yams—

Dioscorea alata and Dioscorea bulbifera, two bananas, Piper methysticum (kava), and several

arboreal species including Artocarpus altilis (breadfruit), Barringtonia asiatica (fish poison

Depth Layer Spit Alo

casi

a m

acro

rrh

iza

(G

ian

t Ta

ro)

Aro

id

Am

orp

ho

ph

allu

s p

aeo

niif

oliu

s

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tilis

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cu

rcu

ma

lon

ga

(Tu

rme

ric)

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

alat

a

(C

om

mo

n Y

am)

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Dio

sco

rea

nu

mm

ula

ria

(Sp

iny

Yam

)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Ipo

mo

ea

bat

atas

(Sw

ee

t P

ota

to)

CO

NTA

MIN

ATI

ON

Mo

rin

da

citr

ifo

lia

(In

dia

n m

ulb

err

y)

Mu

sa s

p.

1

(Ban

ana)

Mu

sa s

p.

2

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Pte

rid

ium

sp

.

(Bra

cke

n)

Sola

nu

m t

ub

ero

sum

(Wh

ite

Po

tato

) C

ON

TAM

INA

TIO

N

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ella

)

Tacc

a le

on

top

eta

loid

es

(Po

lyn

esi

an A

rro

wro

ot)

Xan

tho

som

a sa

gitt

ifo

lium

(Arr

ow

leaf

Ele

ph

ant

Ear

Taro

)

Aro

id C

ON

TAM

INA

TIO

N

0-5 1 1

5-10 1 2

10-15 1 3

15-20 1 4

20-25 2 5

25-30 2 6

30-35 2 7

35-40 3 8

40-45 3 9

45-50 3 10

50-55 3 11

55-60 3 12

60-65 3 13

65-70 4 14

70-75 4 15

75-80 4 16

80-85 5 17

85-90 5 18

90-95 5 19

95-100 6 Control

154

tree), Inocarpus fagifer, and Spondias dulcis. These were tabulated according to the presence of

these species, as quantification of classifications at this final stage was not made due to starch

preservation and taphonomy. The distribution of these species in the test unit may also be

subject to these same issues of taphonomy and preservation.

Despite this, some general patterning noted during analysis will be discussed here. Of

particular interest was the observation that several species were present throughout most

stratigraphic layers within the test unit, notably A. paeoniifolius and I. fagifer present in every

layer. These are not primary crops, but are instead recorded ethnographically and through oral

traditions as supplementary or famine foods. Only one species, Musa sp. 1, was present in only

a single deposit (Layer 5). Some interesting stratigraphic patterning emerges in the range of

species recorded within each deposit. Layer 1 (0-20cmbs) contains starch from all three aroids,

both yams, I. fagifer, P. methysticum and S. dulcis. Layer 2 (20-35cmbs) also contains starch

from three aroids, but only one of the yams— D. alata, along with several arboreal species

including B. asiatica, I. fagifer and S. dulcis. Layer 3 is the largest (in terms of thickness) of all

of the deposits recorded within TP2, and has the largest number of species, including all the

previously mentioned species apart from D. bulbifera and Musa sp.1. Layer 4 contains two of

the aroids, A. paeoniifolius and C. merkusii, a single yam species— D. alata, P. methysticum,

and a number of arboreal species including A. altilis, B. asiatica, and I. fagifer. The lowermost

cultural deposit, Layer 5, contained a fairly comprehensive species list, which included all three

aroids, D. bulbifera, both Musa sp., A. altilis, B. asiatica, I. fagifer, P. methysticum and S.

dulcis.

Depth Layer Spit Am

orp

ho

ph

allu

s p

aeo

nii

foli

us

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

alat

a

(C

om

mo

n Y

am)

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Mu

sa s

p. 1

(Ban

ana)

Mu

sa s

p. 2

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ell

a)

0-5 1 1

5-10 1 2

10-15 1 3

15-20 1 4

20-25 2 5

25-30 2 6

30-35 2 7

35-40 3 8

40-45 3 9

45-50 3 10

50-55 3 11

55-60 3 12

60-65 3 13

65-70 4 14

70-75 4 15

75-80 4 16

80-85 5 17

85-90 5 18

90-95 5 19

95-100 6 Control

155

Table 8.14 Final table documenting species represented by archaeological starch within Talasiu TP2 NB

Presence indicated by black squares

Leka (J17)

In total, 623 starch grains were extracted from 12 bulk soil samples taken from the two

excavated test units at Leka (J17), and each of these grains were again classified using DFA to a

suggested species based on the statistical data collected for the reference collection. Each of

these two test units will be analysed separately first, and then the two sets of final classifications

will be discussed together.

The first of these units, TP2, had four soil samples processed for starch extraction. From

these samples, a large list of possible classifications was produced using DFA, and interpreted

with varying levels of confidence. As with the classifications provided for Talasiu TP2, most

species in the reference collection were represented in the list of assignments for the

archaeological starch from Leka TP2. Only four species- Alocasia macrorrhiza, Curcuma

longa, Morinda citrifolia (Indian mulberry), and Pteridium sp. (bracken fern) were not included

in the preliminary list of assignments. Also similar to Talasiu TP2, several of the same species

at Leka TP2 were often classified with high confidence throughout the test unit, including A.

paeoniifolius, I. fagifer and S. dulcis. This is most likely a direct result of the high re-

classification rate of these species within the multivariate analysis of starch morphological

attributes within the reference collection, which created the algorithm for the classification of

archaeological starch. Many other species were classified with moderate confidence, and very

few with low confidence. Some potential contaminants were identified within this test unit,

including I. batatas and S. tuberosum distributed throughout the unit, with low or moderate

confidence.

Table 8.15 Levels of confidence from DFA classification of archaeological starch from Leka TP2. NB High


Once these classifications were assessed using visual checking, a final smaller list of

species was made for the archaeological starch from Leka TP2. These species were all from the

same cultural deposit (Layer 7), as this was the only stratigraphic layer sampled from this test

unit, but there is some variation in the distribution of these species at different depths within this

layer. Several species are present throughout the deposit, including Amorphophallus

Depth Layer Spit Am

orp

ho

ph

allu

s p

aeo

nn

iifo

liu

s

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

alat

a

(C

om

mo

n Y

am)

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Dio

sco

rea

nu

mm

ula

ria

(Sp

iny

Yam

)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Ipo

mo

ea

bat

atas

(Sw

ee

t P

ota

to)

CO

NTA

MIN

ATI

ON

Mu

sa s

p. 1

(Ban

ana)

Mu

sa s

p. 2

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Sola

nu

m t

ub

ero

sum

(Wh

ite

Po

tato

) C

ON

TAM

INA

TIO

N

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ell

a)

Tacc

a le

on

top

eta

loid

es

(Po

lyn

esi

an A

rro

wro

ot)

90-95 7 1

100-105 7 3

110-115 7 5

120-125 7 7

156

paeoniifolius, Cyrtosperma merkusii and Inocarpus fagifer. Artocarpus altilis is identified in all

spits apart from Spit 5 (110-115cmbs), while Spondias dulcis is present in all but Spit 1 (90-

95cmbs). A number of species are present in only one sample, including Colocasia esculenta,

Barringtonia asiatica, Curcuma longa (identified only using visual checking), Dioscorea

esculenta, Musa sp.1, and Piper methysticum. The significance of these identifications will be

discussed later in this section.

Table 8.16 Final table documenting species represented by archaeological starch within Leka TP2

A larger number of samples were processed for Leka TP4 (n=7), although this did not

result in greater quantities of extracted starch. The preliminary classifications of this starch

produced a list of low-to-high confidence assignments that was quite different to that of TP2,

although again four species from the reference collection were not included in this list—

Alocasia macrorrhiza, Xanthosoma sagittifolium, Curcuma longa and Dioscorea pentaphylla.

Very few species were classified with high confidence in any sample. Those species that were

classified with high confidence included Barringtonia asiatica, Inocarpus fagifer, and Musa sp.

2, and represented a mix of cultivated and semi-cultivated species. A number of other species

could primarily be classified with only low level confidence, including Cyrtosperma merkusii,

Artocarpus altilis, Dioscorea esculenta, Dioscorea nummularia, Ipomoea batatas and Tacca

leontopetaloides. The remaining species were mostly classified with moderate level confidence

due to low numbers or low re-classification rates in the reference collection.

Table 8.17 Levels of confidence from DFA classification of archaeological starch from Leka TP4. NB High


Depth Layer Spit Am

orp

ho

ph

allu

s p

aeo

nii

foli

us

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cu

rcu

ma

lon

ga

(Tu

rme

ric)

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Mu

sa s

p. 1

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ell

a)

90-95 7 1

100-105 7 3

110-115 7 5

120-125 7 7

Depth Layer Spit Am

orp

ho

ph

allu

s p

aeo

nn

iifo

liu

s

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

alat

a

(C

om

mo

n Y

am)

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Dio

sco

rea

nu

mm

ula

ria

(Sp

iny

Yam

)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Ipo

mo

ea

bat

atas

(Sw

ee

t P

ota

to)

CO

NTA

MIN

ATI

ON

Mo

rin

da

citr

ifo

lia

(In

dia

n m

ulb

err

y)

Mu

sa s

p. 1

(Ban

ana)

Mu

sa s

p. 2

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Pte

rid

ium

sp

.

(Bra

cke

n)

Sola

nu

m t

ub

ero

sum

(Wh

ite

Po

tato

) C

ON

TAM

INA

TIO

N

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ell

a)

Tacc

a le

on

top

eta

loid

es

(Po

lyn

esi

an A

rro

wro

ot)

95-100 4 1

105-110 4 3

115-120 4 5

125-130 5 7

135-140 5 9

145-150 5 11

155-160 6 13

157

The final analysis of these classifications produced a list of species containing a range

of both primary cultivated and supplementary species. As observed in TP2, the presence of

Solanum tuberosum indicates some contamination within these samples (likely from the

laboratory environment). Layer 4 (95-120cmbs) contained the largest number of species to

which the extracted archaeological starch could be confidently assigned. From within this layer

of mixed shell and clay matrix, starch deriving from three aroids— Amorphophallus

paeoniifolius, Cyrtosperma merkusii and Colocasia esculenta, four yams— Dioscorea alata,

Dioscorea bulbifera, Dioscorea esculenta and Dioscorea nummularia, and a number of tree

crops and supplementary species such as Artocarpus altilis, Barringtonia asiatica, Inocarpus

fagifer, one Musa sp. and Spondias dulcis were extracted. Layer 5 (125-150cmbs) had a much

smaller list of species present, including one aroid— C. merkusii, one yam— D. alata, P.

methysticum (which again may also be a contaminant and will be discussed in Chapter 9), S.

tuberosum, and arboreal species such as A. altilis, I. fagifer and S. dulcis. Layer 6 (155-

160cmbs) had only one species that could be confirmed using visual checking, being S. dulcis.

Table 8.18 Final table documenting species represented by archaeological starch within Leka TP4

When the classifications from these two test units from Leka (J17) are combined, a

much larger overall list of species identified as being utilised from 1300 to 1000 cal BP. This

list includes three aroids— A. paeoniifolius, C. merkusii and C. esculenta, four yams— D. alata,

D. bulbifera, D. esculenta and D. nummularia, P. methysticum, a number of tree crops and

supplementary species such as A. altilis, B. asiatica, I. fagifer, two Musa spp., and S. dulcis.

Heketa (TO-Nt-2)

The single test unit processed for starch at Heketa, TP3, contained a total of 63 starch grains

extracted from seven samples, indicating a very low level of starch preservation compared to

that observed within all of the other test units. Despite this, a number of low-to-high level

confidence classifications were assigned to these grains using DFA. Only two species could be

assigned to starch with high confidence in any of the samples, and these were Inocarpus fagifer

and Spondias dulcis within Spit 1 (40-45cmbs) from Layer 3. These were also classified with

Depth Layer Spit Am

orp

ho

ph

allu

s p

aeo

nii

foli

us

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Co

loca

sia

esc

ule

nta

(C

om

mo

n T

aro

) A

roid

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

alat

a

(C

om

mo

n Y

am)

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Dio

sco

rea

nu

mm

ula

ria

(Sp

iny

Yam

)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Mu

sa s

p. 2

(Ban

ana)

Pip

er

me

thys

ticu

m

(Kav

a)

Sola

nu

m t

ub

ero

sum

(Wh

ite

Po

tato

) C

ON

TAM

INA

TIO

N

Spo

nd

ias

du

lcis

(Ota

he

ite

Ap

ple

or

Am

bar

ell

a)

95-100 4 1

105-110 4 3

115-120 4 5

125-130 5 7

135-140 5 9

145-150 5 11

155-160 6 13

158

moderate confidence in other samples. Another seven species were identified with

predominantly moderate levels of confidence, and this list includes Amorphophallus

paeoniifolius, Barringtonia asiatica, Dioscorea bulbifera, Musa sp. 2, Piper methysticum,

Pteridium sp., and Solanum tuberosum (contaminant). Six remaining species could only be

classified with low confidence, including Alocasia macrorrhiza, Cyrtosperma merkusii,

Artocarpus altilis, Dioscorea esculenta, and Ipomoea batatas. The remaining species from the

reference collection were not represented by any archaeological starch from TP3.

Table 8.19 Levels of confidence from DFA classification of archaeological starch from Heketa TP3. NB High


Table 8.20 Final table documenting species represented by archaeological starch within Heketa TP3

From this list of classifications, a final table of species identified in Heketa TP3 was

produced. The distribution of these classifications within the three sampled cultural deposits

indicates some variation among the types of species present, but very little variation in the

number of species. Layer 3 (40-75cmbs) contains all four of the aroids— A. macrorrhiza, A.

paeoniifolius, C. esculenta and C. merkusii, P. methysticum, several arboreal species including


casi

a m

acro

rrh

iza

(G

ian

t Ta

ro)

Aro

id

Am

orp

ho

ph

allu

s p

aeo

nii

foli

us

(El

ep

han

t Fo

ot

Yam

) A

roid

Art

oca

rpu

s al

tili

s

(B

read

fru

it)

Bar

rin

gto

nia

asi

atic

a

(Fi

sh P

ois

on

Tre

e)

Cyr

tosp

erm

a m

erk

usi

i

(G

ian

t Sw

amp

Tar

o)

Aro

id

Dio

sco

rea

bu

lbif

era

(B

itte

r Y

am)

Dio

sco

rea

esc

ule

nta

(Le

sse

r Y

am)

Ino

carp

us

fagi

fer

(Tah

itia

n c

he

stn

ut)

Ipo

mo

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159

A. altilis, I. fagifer, S. dulcis, and one probable contaminant- I. batatas. Layer 4 (80-90, and

100-105cmbs) contains all of the aroids apart from C.merkusii, a range of arboreal species

including A. altilis, I. fagifer, and Musa sp. 2, and also I. batatas. Layer 5 represents an ash lens

within Layer 4, and therefore was expected to contain very little, if any starch. During

processing only a few grains were extracted from this deposit, and only one confident

classification could be assigned to these grains during this final stage of analysis, being I.

fagifer.

Figure 8.5 Archaeological and reference starch: (A) archaeological starch identified as Artocarpus altilis, (B)

modern starch of A. altilis, (C) archaeological starch identified as Alocasia macrorrhiza, (D) modern starch of

A. macrorrhiza, (E) archaeological starch identified as Amorphophallus paeoniifolius, (F) modern starch of A.

paeoniifolius, (G) archaeological starch identified as Barringtonia asiatica, (H) modern starch of B. asiatica, (I)

archaeological starch identified as Colocasia esculenta, (J) modern starch of C. esculenta, (K) archaeological

starch identified as Curcuma longa, (L) modern starch of C. longa, (M) archaeological starch identified as

Cyrtosperma merkusii, (N) modern starch of C. merkusii, (O) archaeological starch identified as Dioscorea

alata, (P) modern starch of D. alata.

160

Figure 8.6 Archaeological and reference starch cont.: (Q) archaeological starch identified as Dioscorea

bulbifera (R) modern starch of D. bulbifera, (S) archaeological starch identified as Dioscorea esculenta, (T)

modern starch of D. esculenta, (U) archaeological starch identified as Dioscorea nummularia, (V) modern

starch of D. nummularia, (W) archaeological starch identified as Inocarpus fagifer, (X) modern starch of I.

fagifer, (Y) archaeological starch identified as Ipomoea batatas, (Z) modern starch of I. batatas, (AA)

archaeological starch identified as Musa sp., (AB) modern starch of Musa sp., (AC) archaeological starch

identified as Piper methysticum, (AD) modern starch of P. methysticum, (AE) archaeological starch

(contaminant) identified as Solanum tuberosum, (AF) modern starch of S. tuberosum, (AG) archaeological

starch identified as Spondias dulcis, (L) modern starch of S. dulcis.

Comparison of modern Pacific production systems

Comparative ethnographic examples from the Western Pacific region were analysed to establish

the range of plant species exploited through production or collection techniques. Nutritional,

labour, and productivity data were collated from published examples, to assess and compare the

nature of decision-making in a variety of production systems. These variables will be compared

and contrasted to discuss decision-making and crop selection. Five systems from the Western

Pacific were chosen due to the nature of comparable data available from modern ethnographic

studies. These included the Gadio Enga of the New Guinea Highlands (Dornstreich 1977),

161

Tongatapu (Ministry of Agriculture and Forestry 2001), Bellona Island (Christiansen 1975),

Ontong Java (Bayliss-Smith 1973, 1977, 1986) and Anuta (Yen 1973b) in the Solomon Island

Outliers. These systems were chosen based on the quality and consistency (in terms of time

frame for data collection) of data available within each ethnographic study, and to represent a

variety of environmental contexts (atoll, high island, raised limestone islands). Several systems

also involved some use of cash-cropping (Bellona, Ontong Java and Tongatapu), but it will be

argued here that these cannot be easily separated from subsistence production as these

contribute to total efficiency (total de-facto output divided by primary and secondary inputs)

(Bayliss-Smith 1977) within these systems.

Data was collated on the range of plant species cultivated within each system, and the

labour inputs and yields for each of these. Units of labour inputs were recorded as hours

invested in agricultural production and collection of gathered species, specifically those invested

in garden preparation, maintenance and harvesting of crops. These were compared to outputs in

terms of yield in kilos and nutritional benefits over the same time frame. These figures were

used to calculate basic efficiency or rate of return ratios for each of these species in terms of

nutritional and yield outputs to labour investment inputs. Understanding the basic energetic

inputs to output ratios of these systems, without consideration of variables such as social values,

acreage planted or harvested, seasonal variation and single or multi-cropping techniques is an

important first step towards detailing the nutritional costs and benefits each system within an

Human Ecological framework. While it is important to acknowledge the role that other variables

play in decision-making, it is not possible to create a model that incorporates all of them. These

variables cannot be determined archaeologically, and so providing basic quantifiable nutritional,

labour and productivity data may at least allow interpretation of the past through modelling

hypothetical and testable production systems.

Nutrition

The exploited plant species listed within each of the ethnographic examples, many of which

feature in the archaeobotanical record from of Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-

Nt-2), were assessed for their calorific, protein, fat and carbohydrate values for 100g of edible

plant material. Some spices and ceremonial or medicinal plants such as kava (Piper

methysticum) and betel nut (Areca catechu) were also included in this analysis, primarily

because these were cultivated and could have contributed to dietary needs, even if that was not

their primary purpose. Nutritional data was collected and collated for these species, allowing

comparisons to be made across each system. A total nutritional figure per 100g for each species

was created that added all of the values together. These species were considered separately, and

then as groups described by their authors as horticultural, semi-cultivated, or gathered (or close

synonyms of these such as gardening). These nutritional values are heavily relied upon in the

literature on Evolutionary Ecology and Human Ecology to predict subsistence choices, and

162

provide interesting comparison with ethnographically recorded cases of labour and energy

investment.

Gadio Enga, New Guinea

Of the modern systems analysed, the largest range of utilised plant species was present within

the Gadio Enga system observed by Dornstreich (1973, 1977) in Highland New Guinea. A total

of 35 species was recorded over an entire subsistence season (one year). Animal foods were

included in this dataset and contributed to 25% of dietary protein and 75% of fats, but were not

included in this modelling exercise which targets the role of plants within diet. A range of

nutritional data was collated for species, and the mean of these ranges was used as a final figure

for comparison. The species were broken down into groups including horticulture, gathered,

sago and silviculture—which involves controlling the establishment, growth, composition,

health and quality of forests to meet cultural needs. Interestingly, those species with the highest

calorific value for 100g of edible plant were many of the arboreal species that were either

managed through silviculture or gathered (see Table 8.21). These included semi-cultivated

Pandanus spp., and gathered Canarium spp., Macaranga spp., and Elaeocarpus sp. Root crops

grown through horticulture such as Colocasia esculenta, Dioscorea spp. and Ipomoea batatas

were ranked 11th, 12th and 15th according to calorific value within this system, where highest

calorific value ranked 1 and lowest value ranked 35. In terms of protein value within the same

quantity of edible plant, a similar pattern within the Gadio Enga system is evident, although the

top ranked species for protein is the introduced Abelmoschus manihot, a horticulturally

produced plant. Aside from this cultigen and Phaseolus vulgaris, the horticultural species

generally rank very low compared to the silvicultural and gathered arboreal species.

Arboreal species also rank very highly in fat content, comprising the top eight-ranked

species within the system. The highest ranked horticultural species is P. vulgaris which was

ranked 9th, followed by A. manihot at 10th. The primary root crops are scattered throughout the

rankings below these, with Colocasia esculenta ranked 16th, Dioscorea spp. ranked 26th and

Ipomoea batatas ranked 28th. Patterning within the ranking of species for carbohydrate value

differs from those seen within the other nutritional values. Metroxylon spp. (sago) pith has the

highest amount of carbohydrates per 100g within the Gadio Enga system. Several arboreal fruits

rank just below this crop, but root crops such as C. esculenta (ranked 4th) rank higher than that

seen within the other values.

163

Table 8.21 Nutritional figures and rankings for species within the Gadio Enga system according to calories, protein, fats, carbohydrates and total nutrition figures (data from Dornstreich

1974, 1978)

Species Mean kcal Rank kcal Protein mean Rank protein Fat mean Rank Fat Carbohydrates mean Rank carbohydrates Total figures Overall rank nutrition

Abelmoschus manihot 369.6 5 21.1 1 2.8 10 15.002 14 408.5 5

Areca catechu 249.0 8 5.0 10 4.0 7 47 2 305.0 8

Artocarpus altilis flesh 82.5 16 2.6 16 0.9 11 19.0 12 105.0 17

Artocarpus altilis seeds 150.0 9 6.0 9 0.5 14 30.0 5 186.5 10

Canarium spp. 644.0 2 14.2 5 68.5 1 5.5 27 732.2 2

Carica papaya 43.0 22 0.5 32 0.3 18 11.0 18 54.8 23

Colocasia esculenta 132.5 11 1.7 21 0.4 16 31.6 4 166.2 11

Cucumis sativa 16.0 29 0.6 30 0.1 28 3.6 29 20.3 33

Curcubita moschata 45.0 20 1.0 26 0.1 28 11.7 17 57.8 22

Cympobogon citratus 25.0 27 2.5 17 0.1 28 0.0 33 27.6 31

Dioscorea spp 128.0 12 1.8 20 0.1 26 26.9 7 156.7 13

Diplazium sp. 341.0 6 14.3 4 0.1 26 8.3 21 363.7 7

Edible ferns 50.0 18 0.3 34 3.2 8 6.0 24 59.5 21

Elaeocarpus sp. 375.0 4 15.0 3 30.0 4 16.0 13 436.0 4

Ficus sp. 13.0 32 7.6 8 9.0 5 5.3 28 34.9 28

Gnetum gnemon 28.0 26 5.0 10 0.2 24 11.0 18 44.2 27

Inocarpus fagifer 240.0 9 4.5 12 4.5 6 40.0 3 289.0 9

Ipomoea batatas 95.0 15 1.6 22 0.1 28 20.1 10 116.8 15

Lagenaria siceraria 14.0 30 0.6 30 0.0 33 3.4 30 18.0 34

Luffa sp. 13.0 32 0.7 29 0.3 17 14.34 15 28.3 30

Macaranga spp. 601.0 3 18.9 2 60.4 3 7.4 22 687.7 3

Manihot esculenta 135.0 10 0.9 28 0.0 33 24.0 8 159.9 12

Metroxylon spp. 323.5 7 0.3 34 0.3 18 79.0 1 403.1 6

Musa spp. 113.5 13 1.2 25 0.3 18 27.3 6 142.3 14

Oenanthe javanica 40.0 23 3.6 15 0.3 18 6.0 24 49.9 25

Pandanus spp. 683.0 1 11.9 6 66.0 2 22.0 9 782.9 1

Pangium edule 40.0 23 1.0 26 0.1 28 20.0 11 61.1 19

Phaseolus vulgaris 97.0 14 8.1 7 3.0 9 0.0 33 108.1 16

Piper betel 44.0 21 4.0 14 0.4 15 6.0 24 54.4 24

Rorippa sp. 17.0 28 2.0 19 0.3 23 3.0 31 22.3 32

Rungia sp. 14.0 30 2.4 18 0.3 18 0.1 32 16.8 35

Saccharum edule 38.0 25 4.1 13 0.2 24 5.5 27 47.8 26

Saccharum officinarum 58.0 17 0.5 32 0.0 33 14.0 16 72.5 18

Setaria palmifolia 22.0 27 1.4 24 0.6 13 6.5 23 30.5 29

Zingiber zerumbet 48.0 19 1.5 23 0.9 11 9.5 20 59.9 20

164

A total nutritional figure was created by combining the values for calories, protein, fat

and carbohydrates for each species from 100g of edible material (see Figure 8.7). This enabled

an overall comparison of all species within the system. According to this value, Pandanus spp.

had the highest nutritional value with a total figure of 782.9/100g, followed by a number of

gathered arboreal species. The highest ranked horticulturally produced crop is again A. manihot,

with a figure of 408.5/100g, while root crops such as C. esculenta rank 11th with a figure of

166.2/100g, and Dioscorea spp. rank 13th with a figure of 156.7/100g. When the averages of

each of the production groups are compared, sago production ranks the highest; however, this is

biased by this group containing only this single species. When the remaining groups are

compared, those species grown using silviculture appear to have the highest total nutrition

figures with an average of 246.4/100g, followed closely by gathered species which have an

average of 225.9/100g. Surprisingly, horticulturally produced species have the lowest average—

99.4/100g within the Gadio Enga system.

Figure 8.7 Nutritional comparison of species within the Gadio Enga plant production system (data from

Dornstreich 1974, 1978)

Bellona, Solomon Islands

The plant production system on Bellona was recorded by Christiansen (1975) between the years

1965-66, describing a total of 29 plant species utilised within this system. Species within this

system were categorised by the author into two groups: horticulture and semi-cultivated. The

latter group includes plants which require some anthropogenic manipulation for initial growth

but are mostly untended after this time apart from harvesting on a regular basis or

opportunistically. This semi-cultivated category includes many arboreal species from which

fruits are harvested and mostly eaten raw, or through some processing to remove toxins

165

(Christiansen 1975:36-7). Gathering or hunting of plant, animals and fish is described by

Christiansen as a means of filling the temporal gap in food supplies during different seasons,

during which the bulk of available foods are sourced from outside horticultural practices for at

least a month or more.

Firstly, in terms of calories, the highest ranked species are again the arboreal semi-

cultivated species such as Pandanus spp. and Canarium spp., which is similar to the rankings

seen in the Gadio Enga system (see Table 8.22). Here though, the highest ranked horticultural

species is Cocos nucifera (coconut), ranked 3rd with a calorific value of 425.5/100g for the

mature meat of the fruit. This is followed by the horticulturally produced root crop Pueraria

lobate (kudzu vine), the rhizome of which has a calorific value of 382/100g. Kudzu is not often

cultivated today, but instead is naturalised on many Pacific Islands. The common root crops

such as Colocasia esculenta (12th) and Dioscorea spp.(14-15th, 17-18th, 23rd) appear within the

middle of the spread of calorific rankings along with Musa spp. (16th). Many of the arboreal

species of which fruits are eaten raw, such as Spondias dulcis and Syzygium spp., rank the

lowest of all the utilised species.

Comparison of protein values reveals a similar pattern to calories. Semi-cultivated

arboreal species dominate the highest rankings based on protein content, with the highest

ranking horticultural species, Artocarpus altilis (seeds) being ranked 6th. Root crops generally

rank very low (>15th), apart from Tacca leontopetaloides (Polynesian arrowroot), which ranks

7th with a protein value of 5.1/100g. The fat content of these species again follows a similar

pattern to calories and protein, with C. nucifera ranking the highest of the horticultural species

with 34-43/100g (ranked 3-4th), followed by T. leontopetaloides ranked at 8th with 2.6/100g. The

remaining root crops all have less than 0.4/100g and rank lower than 15th. Similar to the

patterning observed within the Gadio Enga system, the carbohydrate values of these species

provides a different distribution of rankings compared to the other nutritional figures.

Saccharum officinarum (sugarcane) ranks the highest, with a total value of 100/100g— meaning

that this species is entirely composed of carbohydrates. Root crops such as Alocasia

macrorrhiza, Colocasia esculenta, Tacca leontopetaloides, Ipomoea batatas and Dioscorea spp.

also rank very highly according to carbohydrate value, along with some semi-cultivated arboreal

species. These figures are not all that surprising, considering that the carbohydrate value of

these species is generally argued to be the reason that they were initially domesticated.

166

Table 8.22 Nutritional figures and rankings for species within Bellona Island system according to calories, protein, fats, carbohydrates and total nutrition figures (data from Christiansen

1975)


Alocasia macrorrhiza 106.0 18 2.0 17 0.2 22 22 10 130.1 18

Amorphophallus paeoniifolius 135.0 10 2.2 14 0.1 27 18.19 18 155.5 13

Artocarpus altilis flesh 82.5 22 2.6 12 0.9 12 19.0 17 105.0 22

Artocarpus altilis seeds 150.0 9 6.0 6 0.5 13 30.0 5 186.5 10

Burckella sp. 56.0 25 1.1 25 1.3 11 20.1 12 78.5 24

Canarium spp. 644.0 2 14.2 2 68.5 1 5.5 27 732.2 2

Canavalia sp. 372.0 6 34.8 1 1.5 10 51.7 3 460.0 5

Cocos nucifera immature meat 105.0 20 2.4 13 8.0 7 7.0 26 122.4 19

Cocos nucifera mature meat 425.5 3 4.4 9 43.2 3 10.5 23 483.6 3

Cocos nucifera mature milk 328.5 7 3.4 10 34.5 4 5.5 27 371.9 7


Cucumis melo 34.0 28 0.8 27 0.2 18 8.0 25 43.0 29

Dioscorea alata 119.7 15 2.1 16 0.1 25 19.6 16 141.5 16

Dioscorea bulbifera 106.0 18 1.9 18 0.1 27 25.3 8 133.3 17

Dioscorea esculenta 120.3 14 1.8 19 0.2 21 20.05 14 142.3 14

Dioscorea nummularia 106.7 17 1.7 22 0.1 29 13.3 20 121.7 20

Dioscorea pentaphylla 82.0 23 1.7 20 0.1 25 20.0 15 103.8 23

Ficus sp. 13.0 31 7.6 5 9.0 6 5.3 29 34.9 30

Gnetum sp. 28.0 29 5.0 8 0.2 18 11.0 22 44.2 28

Ipomoea batatas 95.0 21 1.6 23 0.1 23 20.1 12 116.8 21

Mangifera sp. 60.0 24 0.8 27 0.4 14 15.0 19 76.2 25


Morinda citrifolia 38.0 27 2.7 11 1.8 9 12.0 21 54.5 26

Musa spp. 113.5 16 1.2 24 0.3 16 27.3 6 142.3 15

Pandanus spp. 683.0 1 11.9 3 66.0 2 22.0 10 782.9 1

Pueraria lobata 382.0 4 2.1 15 0.1 23 27.1 7 411.3 6

Saccharum officinarium 375.0 5 0.0 31 0.0 30 100.0 1 475.0 4

Spondias dulcis 43.7 26 0.8 27 0.3 16 3.65 31 48.5 27

Syzygium spp. 21.0 30 0.7 30 0.2 18 5.3 29 27.2 31

Tacca leontopetaloides 122.0 13 5.1 7 2.6 8 89.4 2 219.1 9

Terminalia sp. 258.0 8 9.6 4 24.0 5 8.3 24 299.9 8

167

Finally, the total nutritional figures for all 29 plant species within the Bellona Island

system were compared (see Figure 8.8). From these, Pandanus spp. again ranks the highest,

followed by Canarium spp., another group of semi-cultivated arboreal species. The highest

value of the horticulturally produced species was recorded in C. nucifera mature meat with a

total nutritional figure of 483.5/100g. A mixture of cultivated grasses (sugarcane), fruits

(Canavalia spp. and C. nucifera mature milk), and root crops (Pueraria lobata) all had total

figures greater than 300/100g, and thus were ranked higher than the next highest ranked semi-

cultivated species— Terminalia spp. When the two groups are compared, the averages of each

are essentially very similar. Horticulturally produced species have an average total nutritional

figure of 215.8/100g, while semi-cultivated species have an average of 205.9/100g.

Figure 8.8 Nutritional comparison of species within the Bellona Island plant production system, showing

exponential trend lines for horticultural and semi-cultivated taxa (data from Christiansen 1975)

Anuta, Solomon Islands

An ethnographic, ecological and archaeological survey of Anuta was carried out by Yen and

others (1973b) over several field seasons in 1970-71. Details of Anutan subsistence were

recorded over a period of 37 days, with the aim of investigating the reputed intensity of

agricultural practice on the island (Yen and Gordon 1973). The use of 19 plant species was

recorded within this survey. When the nutritional values of these species are compared, some

very different patterning can be observed from both the Gadio Enga and Bellona Island systems,

primarily due to the reduced number of exploited arboreal species (see Table 8.23). Unlike the

other modern systems, the Anutan plant species were not divided by the authors into any

groups. However, since labour and productivity data were recorded for only a few of these, this

was taken to indicate that these were primary crops, while all others were most likely

168

supplementary species. This assumption may not be correct, and so the interpretation of these

categories within the nutritional figures will not carry the same weight as those used in the other

systems.

The archaeology and ecology of Anuta and nearby Tikopia have been compared by researchers

in the past (Firth 1939; Kirch 1995; Kirch and Yen 1982). Agricultural production on Tikopia

was similar to Anuta in a number of ways including major crop dominance, the use of some tree

species as well as root crops, and the mulching of taro and manioc with coconut fronds (Yen

and Gordon 1973). Some important differences also existed in the past between these two

locations. Sweet potato is significantly more important in Tikopia than Anuta, but is produced

alongside other root crops using less intensive agricultural techniques within the mountainous

areas where dryland terracing is absent (Firth 1939; Yen and Gordon 1973). Tikopian

agriculture was instead more intensive in flat corraline areas where rotational practices with

crop successions of taro, manioc or sweet potato predominate. These factors were taken into

consideration alongside the availability of labour and yield data when deciding to use data from

Anuta, rather than Tikopia. It was decided that, as described by Yen (1973), Anuta represented a

highly intensive agricultural system, possibly the most intensive within the Pacific and

presented a unique case study for this modelling exercise.

Calorific comparison indicates that the highest ranked species are the few arboreal

species within this system, including Canarium spp. with a value of 644/100g, followed by

mature meat of Cocos nucifera with a value of 425.5/100g. Those species with little other data

recorded, being supplementary species such as Curcuma longa (turmeric), Metroxylon

salomonense (sago), and Inocarpus fagifer, are often ranked higher than ‘primary crops’ such as

Colocasia esculenta, Manihot esculenta (cassava), and Cyrtosperma merkusii (giant swamp

taro). A slightly different range of supplementary crops dominate the highest rankings according

to protein content. Canarium spp. again takes out the top rank with a value of 14.2/100g,

followed by another fruit tree, Barringtonia procera, with a value of 9.7/100g. These arboreal

species are then followed in ranking by a number of root crops (Curcuma longa and Tacca

leontopetaloides). The highest ranked ‘primary crop’ is Cocos nucifera with a protein value of

4.35/100g within mature meat. All primary root crops have a protein value of less than 2/100g.

Comparison of the fat content of these plant species indicates that both primary and

supplementary arboreal species generally have higher values than root crops. Those that differ

from this trend include C. longa with a ranking of 3rd, and T. leontopetaloides with a ranking of

9th out of the 21 total species. Carbohydrate values provide a different trend, but both of these

root crops again rank very highly. In fact, T. leontopetaloides has the highest carbohydrate

content with a value of 89.4/100g. Primary root crops such as Colocasia esculenta, Dioscorea

169

spp. and Manihot esculenta all range from 20-30/100g and rank in the top ten of the 19 species.

Again, this trend was expected.

The overall nutrition figures suggest that in general, those species grouped here as

supplementary have higher nutritional value than those grouped as primary crops (Figure 8.9),

as expected if production costs are lower for certain crops with low-to-medium nutritional

value. The averages of these groups confirm this trend, where supplementary species have an

average of 310.5/100g, while primary species only have an average of 190.3/100g. Within this

pattern it was also observed that arboreal species tend to have higher values than root crops. The

highest overall ranked species was Canarium spp. with a value of 732.2/100g, followed by C.

nucifera mature meat with 483.5/100g. The highest ranked root crop was C.longa with a value

of 437/100g, and the next was T. leontopetaloides with 219.1/100g. The highest ranked primary

root crop was C. esculenta, followed closely by M. esculenta.

170

Table 8.23 Nutritional figures and rankings for species within Anutan system according to calories, protein, fats, carbohydrates and total nutrition figures (data from Yen 1973b)



Areca catechu 249.0 7 5.0 5 4.0 8 47 4 305.0 7

Artocarpus altilis 82.5 19 2.6 10 0.9 11 19.0 15 105.0 19

Barringtonia procera 243.0 8 9.7 2 11.8 4 35.3 6 299.8 8

Burckella obovata 56.0 20 1.1 17 1.3 10 20.1 12 78.5 20

Canarium sp. 644.0 1 14.2 1 68.5 1 5.5 20 732.2 1





Curcuma longa 354.0 4 8.0 3 10.0 5 65.0 3 437.0 3

Cyrtosperma merkusii 122.0 13 0.5 19 0.2 16 19.91 14 142.6 14

Dioscorea spp. 128.0 12 1.8 13 0.1 18 26.9 9 156.7 13


Ipomoea batatas 95.0 18 1.6 15 0.1 19 20.1 12 116.8 18


Metroxylon salomonense 323.5 6 0.3 21 0.3 14 79.0 2 403.1 4

Musa spp. 113.5 15 1.2 16 0.3 14 27.3 8 142.3 15

Piper betel 44.0 21 4.0 8 0.4 12 6.0 19 54.4 21



171

Figure 8.9 Nutritional comparison of species within the Anutan plant production system, showing exponential

trend lines for primary and supplementary taxa (data from Yen 1973b)

Tongatapu, Tonga Archipelago

In 2001, an agricultural census was conducted by the Tongan Ministry of Agriculture and

Forestry. This included a survey of agricultural holdings, productivity and labour investment,

from which a list was provided of all plant species utilised on Tongatapu. This list contains 22

plant species, and was again broken down for comparative purposes into two groups,

horticultural and semi-cultivated based on ethnographic data from European Contact-era

recordings of subsistence strategies (Beaglehole and Beaglehole 1941; Cook in Beaglehole

1969; Cook 1875; Gifford 1929; La Perouse 1799; La Billardiere 1800; Mariner in Martin 1991;

Maude 1965; Wilson 1799; Waldegrave 1873). This census was chosen over Maude’s (1965)

research based on the geographic scope (all of Tongatapu) and consistency of labour investment

with yield data in terms of the time period of data collection (one year).

The distribution of calorific values of these crops follows a similar trend to most of the

other modern systems. Arboreal species including Pandanus spp., Canarium spp. and Cocos

nucifera have the highest rankings, while the root crops are ranked below these at 7th (Colocasia

esculenta), 8th-11th (Dioscorea spp.) and 10th (Xanthosoma sagittifolium) (see Table 8.24). All

three varieties of Musa spp. rank just below these with calorific values ranking from 11th to 13th.

Comparison of protein content indicates that arboreal species again take out the top 9 rankings,

but within these are a number of horticulturally produced crops such as A. altilis with a protein

value of 2.55/100g, and C. nucifera. The highest ranked root crop is A. macrorrhiza with a

value of 1.95/100g, followed by C. esculenta with a value of 1.7/100g. The lowest ranked

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species are semi-cultivated fruit crop S. dulcis and horticulturally produced Piper methysticum

(kava), which is cultivated as a sedative for medicinal and recreational consumption, and is

therefore not consumed to meet daily nutritional requirements.

The fat content of these 20 species included in this nutritional comparison demonstrate

a very similar pattern to that observed within both other systems, and also within the previously

described values. Many arboreal species are ranked highest, with fat content values greater than

1/100g. The highest ranked root crop is X. sagittifolium (elephant ear taro) with a value of

0.4/100g, followed by C. esculenta. All three Musa spp. have values from 0.3-0.4/100g and so

rank closely with these root crops. Ipomoea batatas, on the other hand, is ranked very low with

a value of only 0.1/100g. The ranking of carbohydrate values again demonstrate the high values

of horticulturally produced crops such as C. esculenta (31.6/100g), Musa spp. (27.3-32/100g),

Dioscorea spp. (19-26.85/100g), and X. sagittifolium (23.63/100g).

When these nutritional figures are combined, it would appear that arboreal species again

rank much higher than root crops (see Figure 8.10). Once again Pandanus spp. is ranked the

highest, followed by Canarium spp. and C. nucifera. The highest ranked root crop is also C.

esculenta, followed by one of the recorded Dioscorea sp. This reflects the overall similarities in

the species composition of the Tongan system with the others. When the averages of the two

horticultural and semi-cultivated groups are compared, it becomes clear that the semi-cultivated

species have greater overall nutritional value than the horticultural species. The average for the

semi-cultivated group is 337.9/100g, while that for the horticultural species is much lower at

183.8/100g.

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Table 8.24 Nutritional figures and rankings for species within Tongan system according to calories, protein, fats, carbohydrates and total nutrition figures (data from Ministry of Agriculture

and Forestry 2001)

Species Mean kcal Rank kcal Mean protein Rank protein Fat mean Rank Fat Carbohydrates mean Rank carbohydrates Total figures Overall rank nutrition



Artocarpus heterophyllus 95.0 17 1.7 13 0.6 9 23.0 9 120.3 17

Canarium sp. 644.0 2 14.2 1 68.5 1 5.5 19 732.2 2





Dioscorea sp. 1 128.0 8 1.8 11 0.1 18 26.9 6 156.7 8

Dioscorea sp. 2 122.0 11 2.1 9 0.1 21 19.6 13 143.8 13

Disocorea sp. 3 128.0 8 1.8 11 0.1 18 26.9 6 156.7 8


Ipomoea batatas 95.0 17 1.6 15 0.1 20 20.1 12 116.8 18

Morinda citrifolia 38.0 21 2.7 6 1.8 7 12.0 16 54.5 20

Musa sp. 1 122.0 11 1.3 17 0.4 11 32.0 2 155.7 10

Musa sp. 2 113.5 13 1.2 18 0.3 14 27.3 4 142.3 14

Musa sp. 3 113.5 13 1.2 18 0.3 14 27.3 4 142.3 14

Pandanus sp. 683.0 1 11.9 2 66.0 2 22.0 10 782.9 1

Piper methysticum 6.0 22 0.2 22 0.5 10 0.2 22 6.9 22


Spondias dulcis 43.7 20 0.8 20 0.3 14 3.65 21 48.5 21

Xanthosoma sagittifolium 125.0 10 1.5 16 0.4 11 23.6 8 150.5 11

174

Figure 8.10 Nutritional comparison of species within the Tongan plant production system, showing

exponential trend lines for horticultural and semi-cultivated taxa (data from Ministry of Agriculture and

Forestry 2001)

Ontong Java Atoll, Solomon Islands

The atoll of Ontong Java was surveyed by Bayliss-Smith (1973, 1977, 1986) from 1970-1971 as

a component of his doctoral research and part of the South Pacific Smallholder Project. This

survey targeted agricultural production and associated ecosystem manipulation over time, with a

focus on the limits of island carrying capacity. Through this, a total of 13 utilised plant species

were recorded, including a range of tree crops from which fruits were harvested and also a

number of traditional and recently introduced root crops. Most of the atoll is divided into

specific ecosystems or vegetation units from which particular food products are extracted. Cash-

cropping involving copra production and exports also have enabled other subsistence products

to be imported back into the island. These plant species can be roughly divided into two groups,

primary and supplementary based on Bayliss-Smith’s (1977) description of production

techniques and energy investment. For example, Curcuma longa is grown extensively on the

island and is cultivated as a form of social production rather than subsistence. This species is

still therefore grouped here as primary rather than a supplementary subsistence crop.

A calorific comparison of species within the Ontong Java system ranks Pandanus

tectorius highest, with a value of 683/100g (see Table 8.25). Within this system, Pandanus is

cultivated within coconut woodland and is considered a primary crop. Following this in the

calorific ranking is Cocos nucifera, and then Saccharum officinarum (sugarcane) which are both

primary cultigens. Other arboreal species such as Carica papaya (papaya) and Artocarpus altilis

175

(breadfruit) rank at the bottom of the system, while Musa sp. also ranks relatively low at 10th.

The highest ranked primary root crop is C. longa, followed closely by C. esculenta and X.

sagittifolium. In terms of protein, Pandanus also ranks the highest, and is followed by one

primary and one supplementary root crop, C. longa and Tacca leontopetaloides. Interestingly,

the next highest ranked primary root crop according to protein value is Alocasia macrorrhiza.

Patterning of fat content follows very closely that of protein values, with some minor

reshuffling within the rankings. The same four species have the highest rankings— a

combination of both arboreal and root crops, and supplementary and primary crops. The lowest

ranked species is S. officinarum with a fat value of 0/100g, ranked just below Ipomoea batatas

which has a fat value of 0.1/100g. The ranking of these species according to carbohydrate

values follows a now well-established pattern, dominated by high-ranked primary and

supplementary root crops such as T. leontopetaloides (1st), C. longa (2nd), and C. esculenta (3rd).

The overall nutritional figures reflect the consistently high rankings of arboreal species

such as P. tectorius and C. nucifera, as well as supplementary root crops including C. longa and

T. leontopetaloides (see Figure 8.11). The primary root crops were ranked 7th and below. When

the averages of the two groupings are compared, there is only a slight difference between them.

Primary crops have a slightly higher average (265.8/100g) than those species categorised as

supplementary (222.8/100g).

176

Table 8.25 Nutritional figures and rankings for species within Ontong Java system according to calories, protein, fats, carbohydrates and total nutrition figures system (data from Bayliss-

Smith 1973, 1986)




Carica papaya 43.0 15 0.5 14 0.3 11 11.0 12 54.8 15





Curcuma longa 354.0 4 8.0 2 10.0 4 65.0 2 437.0 3

Cyrtosperma merkusii 122.0 8 0.5 13 0.2 12 19.91 9 142.6 10

Ipomoea batatas 95.0 13 1.6 10 0.1 14 20.1 8 116.8 13

Musa sp. 113.5 10 1.2 12 0.3 10 27.3 4 142.3 11

Pandanus tectorius 683.0 1 11.9 1 66.0 1 22.0 6 782.9 1



Xanthosoma sagittifolium 125.0 7 1.5 11 0.4 8 23.6 5 150.5 8

177

Figure 8.11 Nutritional comparison of species within the Ontong Java plant production system, showing

exponential trend lines for primary and supplementary taxa (data from Bayliss-Smith 1973, 1986)

Nutritional comparisons of groupings

Some basic statistical analyses were carried out to test whether the overall nutritional figures of

species in each grouping or category in each modern system were statistically different. These

categories were compared using Student’s two-sample t-test, to evaluate the difference in means

between the two categories in light of the pooled standard deviations from both categories

(Drennan 1996). The null hypothesis is that the difference between means of the two

populations is not greater than 0, while the alternative hypothesis argues that the mean

difference is greater than 0. A simple mean comparison may suggest that two groups (or

populations) are different, but the t-test indicates how significant that difference actually is.

Firstly, the pooled standard deviation and pooled standard error for each system were calculated

and then a final figure that indicates the difference between these categories according to

standard errors. This figure was then used to explain the probability that the two categories are

in fact statistically different using the t test distribution table. Within archaeology the generally

accepted probabilty and associated confidence level is 95% or over to statistically reject the

null-hypothesis.

Within the Gadio Enga system the horticulture and gathered categories were compared

nutritionally (see Table 8.26). The overall nutritional figures of these two categories were

shown through Student’s two-sample t-test to have a difference of 1.76 standard errors, arguing

that the probability of these groups being from the same population is 20%. Therefore, despite a

178

difference in mean of 126.4, these are not significantly different. The comparison of categories

within Bellona Island, Tonga, and Ontong Java all proved that these systems were not

statistically different based on the number of species being compared and the associated

confidence in statistical differences between nutritional values. The only system that was close

to having two statistically different categories was that from Anuta. The comparison of means

from primary and supplementary species on Anuta proved that these were nutritionally different

with 90% confidence by 1.93 standard errors, but not enough to reject the null hypothesis that

these are from the same population.

Table 8.26 Statistical comparison of species’ groupings in example systems according to overall nutrition

figures/100g

Labour investment

Looking beyond the nutritional value of species within each of the example systems, the amount

of labour invested in the cultivation, maintenance, harvesting and storage provides a significant

insight into the nature of decision-making within these systems. Energy invested into food

production can be used as a gauge of where subsistence preferences lie in terms of nutritional

outputs, or other social or environmental factors. These labour values will be compared with a

variety of these nutritional outputs to discuss diet and productivity within plant food production

system.


Labour investment in this system was recorded by Dornstreich (1973) as instances of activity

rather than as accumulated hours or energy spent cultivating and processing plant species.

Although an ‘instance of activity’ could equate to any number of man-hours, these data enables

at least some basic comparison of labour investment and therefore inputs into the Gadio Enga

plant production system. When these figures are compared and then ranked, it becomes clear

that labour is directed towards some species and plant categories far more than others.

The highest ranked species by a significant margin is Metroxylon spp., or sago, with a

total of 148 recorded instances of activity over the observed subsistence season (see Table 8.27,

Figure 8.12). Sago production was noted by Dornstreich (1973, 1977) to provide a significant

component of the Gadio Enga diet. Many lower ranked horticultural species share similar values

for labour investment, due to the fact that recorded instances of activity were divided between

Example system Pooled standard deviation Pooled standard error Difference Confidence Mean difference

Gadio Enga (horticulture vs

gathered) 188.7 71.6 1.8 90% 126.5

Bellona Island (horticulture vs

semi-cultivated) 201.5 74.8 0.3 <50% 10.0

Tonga 2001 Agricultural Survey (primary vs

supplementary crops) 197.6 94.7 1.6 80% 154.1

Ontong Java (primary vs

supplementary crops) 203.6 118.9 0.4 <50% 43.0

Anuta Atoll (primary vs


Nutrition (total figures/100g)

179

particular resource areas at various altitudes and distances from the village. For this reason,

Dioscorea spp. is ranked 2nd with 39.5 instances of activity, followed by a number of cultivated

crops such as Abelmoschus manihot, Colocasia esculenta, Cucumis sativa (cucumber), Ipomoea

batatas and Manihot esculenta (cassava or tapioca). Many gathered arboreal species such as

Ficus sp. (fig), Elaeocarpus sp., Artocarpus altilis and the herb Oenanthe javanica (Japanese

parsley) are ranked the lowest within this system according to labour. Most surprising in this

data is the very low ranking of A. altilis, as breadfruit is usually cultivated in most Pacific

production systems for seeds or flesh and therefore time is invested in initial planting, weeding,

harvesting and storage. This ranking may reflect overall or situational subsistence decision-

making. For example, that year breadfruit may not have grown well due to environmental

factors and so labour was invested elsewhere, or that once breadfruit was established trees

required little labour investment.

Table 8.27 Labour investment into species within the Gadio Enga system (data from Dornstreich 1974, 1978)

Species Labour inputs- instances of activity Rank inputs

Abelmoschus manihot 30.1 3

Areca catechu 20.7 21

Artocarpus altilis flesh 10.3 26

Artocarpus altilis seeds 10.3 26

Colocasia esculenta 30.1 3

Cucumis sativa 30.1 3

Curcubita moschata 30.1 3

Cympobogon citratus 30.1 3

Dioscorea spp 39.5 2

Edible ferns 28.8 18

Elaeocarpus sp. 11.8 23

Ficus sp. 28.8 18

Ipomoea batatas 30.1 3

Manihot esculenta 30.1 3

Metroxylon spp 148.0 1

Musa spp. 30.1 3

Oenanthe javanica 11.8 23

Pandanus spp. 20.7 21

Pangium edule 11.8 23

Phaseolus vulgaris 30.1 3

Piper betel 30.1 3

Rorippa sp. 30.1 3

Rungia sp. 28.8 18

Saccharum edule 30.1 3

Saccharum officinarum 30.1 3

Setaria palmifolia 30.1 3

Zingiber zerumbet 30.1 3

180

Figure 8.12 Labour comparison of species within the Gadio Enga system (data from Dornstreich 1974, 1977)


Christiansen (1975) recorded hours of labour over a year, according to the types of gardens and

species within them. Therefore, many species within the Bellona Island system share the same

figures for labour investment, and so also have the same rankings when all species are compared

(see Table 8.28, Figure 8.13). Despite this, some species stood out within the system. One

example of this is the case of Ipomoea batatas which ranked the highest in the system, with

around 33,000 hours of labour invested in this crop in a year. Either the cultivation of this

species is labour intensive to maintain productive yields, or sweet potato is regarded as a

nutritionally or socially important cultigen and therefore time is invested accordingly to increase

cultivation more than other horticulturally produced species. Such considerations will be

discussed later in the chapter when output to input ratios are calculated. Three Dioscorea spp.

are ranked below this, with labour investment values of 16,683 hours/year. Two of the aroids,

Alocasia macrorrhiza and Colocasia esculenta rank 5th due to a total of 11,872 hours/year being

dedicated to the production of these two cultigens. Horticulturally produced or semi-cultivated

arboreal species such as Cocos nucifera, Burckella sp. and Canarium spp. generally rank below

these root crops. Artocarpus altilis again ranks the lowest according to labour investment, a

trend which requires comparison across these systems.

181

Table 8.28 Labour investment into species within the Bellona Is system (data from Christiansen 1975)

Figure 8.13 Labour comparison of species within the Bellona Island system (data from Christiansen 1975)

Species Labour hrs/yr Rank inputs

Alocasia macrorrhiza 11872.0 5

Amorphophallus paeoniifolius 854.1 11

Artocarpus altilis flesh 60.0 27

Artocarpus altilis seeds 60.0 27

Burckella sp. 854.1 11

Canarium spp. 854.1 11

Canavalia sp. 854.1 11

Cocos nucifera immature meat 3333.3 8

Cocos nucifera mature meat 3333.3 8

Cocos nucifera mature milk 3333.3 8


Cucumis melo 854.1 11

Dioscorea alata 16683.0 2

Dioscorea bulbifera 854.1 11

Dioscorea esculenta 16683.0 2

Dioscorea nummularia 16683.0 2

Dioscorea pentaphylla 854.1 11

Ficus sp. 854.1 11

Gnetum sp. 854.1 11


Mangifera sp. 60.0 27


Morinda citrifolia 854.1 11

Musa spp. 9425.0 7

Pandanus spp. 100.0 26

Pueraria lobata 854.1 11

Saccharum officinarium 854.1 11

Spondias dulcis 60.0 27

Syzygium spp. 60.0 27

Tacca leontopetaloides 854.1 11

Terminalia sp. 854.1 11

182


Labour investment on Anuta was recorded by Yen (1973b) over a 37 day period for a family

group. These figures are compared here according to both species and also grouping (Table 8.29

and Figure 8.14). The highest intensity of labour investment was directed towards horticultural

species, with very little investment in supplementary species. This is an expected trend

according to the nature and definition of the groupings used within this example system. The

highest ranked species according to labour investment is Manihot esculenta with a total of 125.6

recorded hours, followed closely by Colocasia esculenta with 108.6 hours. These two crops

have the highest labour investment by a significant margin, with the next ranked species,

Artocarpus altilis, having only 62.6 hours dedicated to production. The highest ranked

supplementary species are Areca catechu (betel palm) and Piper betel (betel leaf), which are

cultivated together for betelnut consumption, each had only 2.2 hours of labour invested over

the recorded period. The lower ranked species are all those grouped as supplementary aside

from Ipomoea batatas which only had 0.7 hours spent on cultivation and processing.

Table 8.29 Labour investment into species within the Anutan system (data from Yen 1973b)

Species Labour inputs (hrs/37 days) Rank inputs


Areca catechu 2.2 10

Artocarpus altilis 62.6 3

Barringtonia procera 0.7 12

Burckella obovata 24.3 4

Canarium sp. 0.7 12





Curcuma longa 0.7 12

Cyrtosperma merkusii 18.3 6

Dioscorea spp. 0.7 12

Inocarpus fagifer 0.7 12



Metroxylon salomonense 0.7 12

Musa spp. 20.3 5

Piper betel 2.2 10


Tacca leontopetaloides 0.7 12

183

Figure 8.14 Labour comparison of species within the Anutan system (data from Yen 1973b)

Tongatapu, Tonga Archipelago

During the 2001 agricultural census conducted in Tonga, some data was collected on the

amount of labour invested into agricultural production by gender and relationship to the land

(owner, family or worker) per week. These labour figures were used to estimate yearly labour

investment into agriculture. These total figures were further broken down into estimated

species-specific figures through the use of acreage data detailing land dedicated to specific crop

production within the same census (see Table 8.30 and Figure 8.15). This avoided dealing with

the amount of labour dedicated to most European export crops. The patterning in these figures

closely matches that expected based on early historic and ethnographic recordings of Tongan

subsistence production. Most labour in the census was invested in the production of the Early

yam (Dioscorea sp.2, presumably Dioscorea alata) which is known to be a very important

cultigen within Tongan culture and related to surplus production for tributes and festivals.

Around 1,122,947.3 hours of labour were directed towards the production of this crop in the

census year. Ranked just below this species is another horticulturally produced cultigen,

Xanthosoma sagittifolium, which is also a historic introduction into Tonga that is now favoured

over the common taro because large quantities of this species can be grown using established

dryland production techniques. Due to the popularity of this introduction the common taro ranks

3rd, with 1,015,599.1 hours/year of labour investment. Other root crops also rank highly,

including Piper methysticum which ranks 7th with a total of 131,428.5 hours/year of labour

investment. Most semi-cultivated species rank below the horticultural crops, aside from

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184

Pandanus sp., which ranks above one Dioscorea sp., Saccharum officinarum and A. altilis, with

a total of 10,706.9 hours/year investment. It is interesting that Artocarpus altilis once again

ranks low within this system.

Table 8.30 Labour investment into species within the Tongan system (data from Ministry of Agriculture and

Forestry 2001)

Species Labour (hrs/yr) Rank inputs


Artocarpus altilis 5991.6 16





Dioscorea sp. 1 10450.4 14

Dioscorea sp. 2 1122947.3 1

Disocorea sp. 3 461086.1 4

Inocarpus fagifer 3002.1 17


Morinda citrifolia 2942.0 18

Musa sp. 1 73029.6 11

Musa sp. 2 56565.4 12

Pandanus sp. 10707.0 13

Piper methysticum 131428.5 7


Spondias dulcis 259.7 19

Xanthosoma sagittifolium 1069745.0 2

185

Figure 8.15 Labour comparison of species within the Tongan system (data from Ministry of Agriculture and

Forestry 2001)

Ontong Java, Solomon Islands

Energy use and investment of labour within the Ontong Java plant production system over a

year was directed primarily towards the cash-cropping and export of copra from Cocos nucifera.

This species therefore dominates the man-hours dedicated to agriculture on the island, with a

total of 202,960 hours spent cultivating, harvesting and processing this export item over the year

recorded by Bayliss-Smith (1973) (see Table 8.31 and Figure 8.16). Within the ethnographic

study from which this data was extracted, it is argued that the energy investment into export

items rather than subsistence species directly should not be discounted completely as time

wasted. The currency generated from these exports enabled other subsistence items to be

brought into the Ontong Java system that might not be grown or accessed any other way, and

thus still contribute to diet and system outputs, if not directly through a nutritional contribution.

Subsistence items that were grouped as primary crops, such as Colocasia esculenta and

Cyrtosperma merkusii, are ranked just below C. nucifera, with around 43,830 hours/year

dedicated to each of these species. There is an important tradition of turmeric (Curcuma longa)

cultivation on Ontong Java for cultural as well as subsistence reasons, and therefore 9,200

hours/year was spent on the production of this species. Labour investment in all other species

was simply described as dedicated toward village crop cultivation or gathering wild fruits, with

very low time investment in comparison with the aforementioned major horticultural cultigens.

Table 8.31 Labour investment into species within the Ontong Java plant production system (data from Bayliss-

Smith 1973, 1986)

Species Labour inputs (hrs/yr) Rank inputs

Alocasia macrorrhiza 183 7

Artocarpus altilis 183 7

Carica papaya 183 7

Cocos nucifera immature meat 202960 1

Cocos nucifera mature meat 202960 1

Cocos nucifera mature milk 202960 1

Colocasia esculenta 43830 4

Curcuma longa 9200 6

Cyrtosperma merkusii 43830 4

Ipomoea batatas 183 7

Musa sp. 183 7

Pandanus tectorius 183 7

Saccharum officinarum 183 7

Tacca leontopetaloides 183 7

Xanthosoma sagittifolium 183 7

186

Figure 8.16 Labour comparison of species within the Ontong Java plant production system (data from Bayliss-

Smith 1973, 1986)

Labour input comparison of groupings

Student’s t-test and associated confidence distribution tables were again used to calculate

whether the groupings of species for each modern system used in this study were significantly

different according to mean (see Table 8.32). Compared to the levels of confidence in

differences generated for the nutritional data, those established for the labour inputs in each

system were generally much higher. The groupings or categories within three systems were

shown to be statistically different with acceptable confidence. The comparison of labour

investment into horticultural and gathered species in the Gadio Enga plant production system

was shown to be different by 5.8 standard errors with 99.9% confidence. From this, the absolute

means of these groups were shown to be different by a value of 19 hours. Similarly, a

comparison of horticultural and semi-cultivated species within the Bellona Island system

calculated that these two groupings were different by 2.6 standard errors, the probability of

these being different is 98% according to the number of species in each category. Finally, the

difference between primary and supplementary species within the Anutan system was shown to

be 4.6 standard errors, and so can be argued to be different with 100% confidence. The means of

these two categories were different by 14.5 hours. The remaining two systems could not be

shown to be statistically different with high probability in labour investment.

187

Table 8.32 Statistical comparison of species’ groupings in example systems according to labour input figures

Outputs

The nutritional and energy outputs from each of the example systems provide essential data

about the costs and benefits of labour investment into each plant species within production

systems. These figures were calculated based on the productivity or yield for each species

within the time period for which ethnographic data was collected. Because these time periods

vary, these figures cannot be compared directly across the different systems. Here, yield and

associated outputs will be outlined for each species within each Pacific production system.

Because of biases in the data for recorded outputs, the groupings in each example system will

not be statistically compared. The section following this discussion on system outputs will focus

on patterning in the output to input ratios for each species in each of the example systems. These

ratios can be used as a gauge for ‘system efficiency’ according to energy returns.


System output data for the Gadio Enga was recorded over one subsistence season, or a full year.

When the yields for species within this system are directly compared, it becomes clear that the

horticulturally produced species have the greatest productivity (see Table 8.33, Figure 8.17).

The highest yielding species within this season was Colocasia esculenta, from which 1987.4 kg

of edible material was harvested. Ranked just below this was another staple crop, Metroxylon

spp., with a total yield of 1117.4kg. Other arboreal species generally ranked low within the

system, aside from Musa spp. (although these are technically herbs not trees) which rank 4th as

this genus is more like root crops in terms of growth and yields. The highest supplementary

arboreal species was Pandanus spp. which was ranked 13th with a total yield of 28.5kg. Root

crops such as C. esculenta, Ipomoea batatas, and Manihot esculenta, on the other hand,

generally rank relatively high. Dioscorea spp. are the only taxa to differ from this trend, with a

ranking of 14th due to a yield of 13.3kg. It is interesting to note the high yield and associated

rank of edible ferns, which comes in at 7th with a yield of 60.7kg. From these data, the total

yields from each of the groupings revealed an expected pattern. Horticultural production had a

total yield of 2935.1kg, while sago had 1117.4kg, gathering had 220.88kg, and finally

silviculture had only 50kg.


Gadio Enga (horticulture vs

gathered) 8.5 3.3 5.8 99.90% 19.0

Bellona Island (horticulture vs

semi-cultivated) 649.6 243.1 2.6 98% 619.0

Tonga 2001 Agricultural Survey (primary vs


Ontong Java (primary vs


Anuta Atoll (primary vs


Labour Inputs (hours or instances of activity)

188

Table 8.33 Output comparison of species in Gadio Enga plant production system (data from Dornstreich 1974,

1978)

Figure 8.17 Output comparison according to yield for species within Gadio Enga system (data from

Dornstreich 1974, 1978)

Species Yield (kg) Rank Kcal Protein Fats Carbohydrates

Abelmoschus manihot 50.0 9 184.8 10558.8 1395.7 7499.4

Areca catechu 0.7 24 1.8 36.2 29.0 340.7

Artocarpus altilis flesh 10.3 17 8.5 263.9 93.1 1966.3

Artocarpus altilis seeds 10.3 17 15.5 620.9 51.7 3104.6

Colocasia esculenta 1987.4 1 2633.4 33786.5 6956.0 628030.7

Cucumis sativa 4.1 21 0.7 24.7 4.1 148.2

Curcubita moschata 84.0 5 37.8 839.9 84.0 9818.0

Cympobogon citratus 0.4 25 0.1 9.1 0.4 0.0

Dioscorea spp 13.4 14 17.1 234.0 16.7 3589.9

Edible ferns 60.7 7 30.3 182.1 1942.3 3641.8

Elaeocarpus sp. 12.1 16 45.5 1821.9 3643.8 1943.4

Ficus sp. 7.0 19 0.9 532.4 628.5 371.8

Ipomoea batatas 498.2 3 473.3 7971.4 498.2 100140.1

Manihot esculenta 62.5 6 84.4 562.6 0.0 15003.4

Metroxylon spp 1117.4 2 3614.9 3352.3 3352.3 882217.1

Musa spp. 172.3 4 195.6 1981.9 517.0 47049.3

Oenanthe javanica 12.5 15 5.0 449.3 37.4 748.8

Pandanus spp. 28.5 13 194.8 3394.2 18825.1 6275.0

Pangium edule 59.0 8 23.6 590.1 59.0 11802.3

Phaseolus vulgaris 0.2 26 0.2 17.4 6.5 0.0

Piper betel 3.1 22 1.4 124.9 12.5 187.4

Rorippa sp. 44.2 11 7.5 883.4 110.4 1325.2

Rungia sp. 7.0 19 1.0 168.3 21.0 3.5

Saccharum edule 0.1 27 0.0 2.3 0.1 3.1

Saccharum officinarum 29.2 12 16.9 145.9 0.0 4085.8

Setaria palmifolia 47.7 10 10.5 668.1 286.3 3102.0

Zingiber zerumbet 0.8 23 0.4 12.1 7.3 76.8

189


The yield (mT) for each species within the Bellona system was recorded over a single year. The

highest ranked amongst these were three of the yam species— D. alata, D. esculenta and D.

nummularia— each with yields of around 211.7mT over the recorded year (see Table 8.34,

Figure 8.18). Musa spp. ranked 4th with a yield just below these species. This genus represented

the highest ranked arboreal taxa within the system, followed by Cocos nucifera with a yield of

100mT. A number of horticultural root crops such as Ipomoea batatas. Colocasia esculenta, and

Alocasia macrorrhiza rank 8-9th with yields from 65-98mT. Some semi-cultivated arboreal

species exploited for fruits, including Mangifera sp., Spondias dulcis and Syzygium sp., are

ranked 11th with yields of 5mT. The remaining taxa within the system had low yields, and

included a range of both horticultural and semi-cultivated species. Overall, the horticultural

species collectively had a much higher yield than the range of semi-cultivated species, with a

total of 1387.6mT compared to 37.5mT.

Table 8.34 Output comparison of species in Bellona Island system (data from Christiansen 1975)

Species Yield (mT) Rank Kcal Protein Fat Carbohydrates

Alocasia macrorrhiza 65 9 68.9 1267.5 97.5 14300.0

Amorphophallus paeoniifolius 2.5 14 3.4 56.0 1.5 454.8

Artocarpus altilis flesh 2.5 14 2.1 63.8 22.5 475.0

Artocarpus altilis seeds 2.5 14 3.8 150.0 12.5 750.0

Burckella sp. 2.5 14 1.4 27.5 32.5 502.5

Canarium spp. 2.5 14 16.1 355.0 1712.5 137.5

Canavalia sp. 2.5 14 9.3 870.0 37.5 1291.3

Cocos nucifera immature meat 100 5 105.0 2350.0 8000.0 7000.0

Cocos nucifera mature meat 100 5 425.5 4350.0 43200.0 10500.0

Cocos nucifera mature milk 100 5 328.5 3400.0 34500.0 5500.0

Colocasia esculenta 65 9 86.1 1105.0 227.5 20540.0

Cucumis melo 2.5 14 0.9 20.0 5.0 200.0

Dioscorea alata 211.7 1 253.4 4361.0 169.4 41514.4

Dioscorea bulbifera 2.5 14 2.7 48.5 1.5 631.5

Dioscorea esculenta 211.7 1 254.7 3747.1 381.1 42445.9

Dioscorea nummularia 211.7 1 225.9 3493.1 105.9 28198.4

Dioscorea pentaphylla 2.5 14 2.1 43.3 2.0 500.0

Ficus sp. 2.5 14 0.3 189.8 224.0 132.5

Gnetum sp. 2.5 14 0.7 125.0 5.0 275.0

Ipomoea batatas 98 8 93.1 1568.0 98.0 19698.0

Mangifera sp. 5 11 3.0 40.0 20.0 750.0


Morinda citrifolia 2.5 14 1.0 67.5 45.0 300.0

Musa spp. 202 4 229.3 2323.0 606.0 55146.0

Pandanus spp. 2.5 14 17.1 297.5 1650.0 550.0

Pueraria lobata 2.5 14 9.6 52.5 2.5 677.5

Saccharum officinarium 2.5 14 9.4 0.0 0.0 2500.0

Spondias dulcis 5 11 2.2 40.0 15.0 182.5

Syzygium spp. 5 11 1.1 35.0 10.0 265.0

Tacca leontopetaloides 2.5 14 3.1 127.5 64.5 2235.0

Terminalia sp. 2.5 14 6.5 240.0 600.0 207.5

190

Figure 8.18 Output comparison according to yield for species within Bellona system (data from Christiansen

1975)


The outputs of the family garden within the Anutan production system, as recorded by Yen

(1973b) over a 37 day period, were solely derived from primary species. Clearly there is a bias

within the nature of recorded outputs in terms of yield over this time period. Perhaps the season

within which these outputs were recorded was that when only a small number of species were

being harvested. Another option is that the recorders were only given access to data from

particular species. No explanation of the data is given by the authors. In any case, outputs in

terms of yield were recorded for only six of the total 19 species. Highest ranked amongst these

species is Manihot esculenta, with a total yield of 254.7kg over the recorded period (see Table

8.35, Figure 8.19). There is a significant difference between this crop and the yield of the next

highest ranked species, Colocasia esculenta, which had 163.3kg. The remaining taxa all had

yields of less than 50kg. Based on these data, the recorders were able to make estimates for the

expected annual yield of these species from the number of plants or trees within the plantation.

Manioc or Manihot esculenta was expected to have the highest yield of around 2,511kg,

followed by C. esculenta with 1610kg. Breadfruit (Artocarpus altilis) was expected to yield

around 326kg, while Musa spp., was expected to yield only 127kg over a year. Lowest expected

annual yield was from Burckella sp. with only 41kg.

191

Table 8.35 Output comparison of species in Anutan system (data from Yen 1973b)

Figure 8.19 Output comparison according to yield for species within the Anutan system (data from Yen 1973b)

Species Yield (kg) Rank Kcal Protein Fat Carbohydrates

Alocasia macrorrhiza 0.0 0 0.0 0.0 0.0 0.0

Areca catechu 0.0 0 0.0 0.0 0.0 0.0

Artocarpus altilis 33.1 3 27276.9 843.1 297.6 6281.9

Barringtonia procera 0.0 0 0.0 0.0 0.0 0.0

Burckella obovata 4.2 6 2328.6 45.7 54.1 835.8

Canarium sp. 0.0 0 0.0 0.0 0.0 0.0

Cocos nucifera immature meat 0.0 0 0.0 0.0 0.0 0.0

Cocos nucifera mature meat 0.0 0 0.0 0.0 0.0 0.0

Cocos nucifera mature milk 0.0 0 0.0 0.0 0.0 0.0


Curcuma longa 0.0 0 0.0 0.0 0.0 0.0

Cyrtosperma merkusii 20.5 4 24993.9 104.5 32.8 4078.9

Dioscorea spp. 0.0 0 0.0 0.0 0.0 0.0

Inocarpus fagifer 0.0 0 0.0 0.0 0.0 0.0

Ipomoea batatas 0.0 0 0.0 0.0 0.0 0.0


Metroxylon salomonense 0.0 0 0.0 0.0 0.0 0.0

Musa spp. 12.9 5 14619.2 148.1 38.6 3516.3

Piper betel 0.0 0 0.0 0.0 0.0 0.0



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Anuta Output Comparison

Primary crops

Supplementary

192

Tongatapu, Tongan Archipelago

The output data within the 2001 Agricultural Census in Tonga had similar biases to that

observed of the Anutan system. Data from Tongatapu only included yields of the core cultigens,

which have been grouped here as horticultural species. There is therefore a recording bias

towards this category. Aside from these core cultigens, many other horticultural and all

supplementary species were excluded from the ranking based on outputs. It is not likely that

these species had no yield over this time period on Tongatapu, and so to rank these species as

‘0’ for yield would skew the comparisons.

Of those taxa for which there are data, Xanthosoma sagittifolium is ranked the highest

with an annual yield of 13,677.5mT on Tongatapu (see Table 8.36, Figure 8.20). This is not

unexpected due to the popularity in Tonga of this introduced dryland taro from South America.

Ranked just below this with a yield of 13,637.9mT, is the ‘Early yam’ or Dioscorea sp. 2. Again

the high yield of this species is not unexpected due to the cultural significance of this cultigen in

Tonga. The common taro, Colocasia esculenta, had a recorded annual yield of 9,088.7mT, and

was ranked 3rd. Root crops dominate the remaining rankings according to yield, although some

arboreal species are interspersed amongst these, including Musa spp. ranked 7-8th and Pandanus

sp. ranked 9th with a total annual yield of 1,394.5mT.

Table 8.36 Output comparison of species in Tongan system (data from Ministry of Agriculture and Forestry

2001)

Species Yield (mt) Rank Kcal Protein Fat Carbohydrates



Artocarpus heterophyllus 0.0 0 0.0 0.0 0.0 0.0

Canarium sp. 0.0 0 0.0 0.0 0.0 0.0





Dioscorea sp. 1 126.9 10 162.5 2221.1 158.6 34077.5

Dioscorea sp. 2 13637.9 2 16638.3 280941.1 10910.3 2674395.3

Disocorea sp. 3 5599.8 4 7167.7 97996.1 6999.7 1503539.9

Inocarpus fagifer 0.0 0 0.0 0.0 0.0 0.0

Ipomoea batatas 5100.9 5 4845.9 81614.4 5100.9 1025280.9

Morinda citrifolia 0.0 0 0.0 0.0 0.0 0.0

Musa sp. 1 1833.8 7 2237.2 23839.5 7335.2 586819.4

Musa sp. 2 1632.2 8 1852.6 18770.6 4896.7 445598.7

Musa sp. 3 0.0 0 0.0 0.0 0.0 0.0

Pandanus sp. 1394.5 9 9524.2 165941.6 920348.4 306782.8

Piper methysticum 0.0 0 0.0 0.0 0.0 0.0


Spondias dulcis 0.0 0 0.0 0.0 0.0 0.0

Xanthosoma sagittifolium 13677.5 1 17096.9 199691.8 54710.1 3231998.4

193

Figure 8.20 Output comparison according to yield for species within the Tongan system (data from Ministry of

Agriculture and Forestry 2001)


Data recording caused some issues with the comparison of outputs from species within the

Ontong Java plant production system. Four species had no yield data recorded, including all

three of the species classified as supplementary. This biases the grouping comparison towards

the primary species, but it is not likely that this reflects the actual yield data for the recorded

time period. One reason is because of the social importance of turmeric (Curcuma longa)

production mentioned by Bayliss-Smith (1973). Despite this, no yield data are given. Perhaps

environmental limitations affected production that year.

For those species for which yield data is available, Cocos nucifera, ranks the highest

with a total annual yield of 110,700kg (see Table 8.37, Figure 8.21). Of the purely subsistence

crops, Cyrtosperma merkusii ranks the highest with an annual yield of 69,230kg. This is

followed by another aroid, Colocasia esculenta, with a yield of 40,180kg. These two species are

described as core cultigens within the Ontong Java system, grown using wetland techniques that

make the most of the island’s geographic and environmental constraints. Several arboreal

species such as Carica papaya, Musa spp. and Pandanus tectorius all rank above the lowest

ranked root crop, Xanthosoma sagittifolium, which had an annual yield of only 250kg. Perhaps

this dryland species of taro is not as viable as wetland varieties within the atoll environment.

194

Table 8.37 Output comparison of species in Ontong Java production system (data from Bayliss-Smith 1973,

1986)

Figure 8.21 Output comparison according to yield for species within the Ontong Java production system (data

from Bayliss-Smith 1973, 1986)

Output to input ratios: Efficiency calculation

Once the figures for nutritional values, labour inputs, outputs in terms of yield and associated

nutritional returns have been calculated for each species within each system, the ‘efficiency’ of

energy returns can then be calculated. In this study, it was deemed appropriate to focus on the

species that have been identified archaeobotanically at Talasiu (TO-Mu-2), Leka (J17) and the

Heketa (TO-Nt-2) through extracted starch grains and charred macrobotanical remains. This

Species Yield (mT) Rank Kcal Protein Fat Carbohydrates



Carica papaya 9.6 6 4.1 47.9 28.7 1052.7





Curcuma longa 0.0 0 0.0 0.0 0.0 0.0

Cyrtosperma merkusii 69.2 4 84.5 353.1 110.8 13783.7

Ipomoea batatas 4.7 7 4.5 75.2 4.7 944.7

Musa sp. 1.8 8 2.0 20.2 5.3 480.5

Pandanus tectorius 1.3 9 8.9 155.9 864.6 288.2



Xanthosoma sagittifolium 0.3 11 0.3 3.7 1.0 59.1

195

decision was made firstly due to the large range of species within each system, and secondly as

the ultimate aim of this analysis is to assess the variation of outputs to inputs within a range of

production systems, in order to model archaeological systems. Each of the archaeological

species was therefore compared across each of the example systems according to energy and

nutritional outputs per time unit. Firstly, a ratio is created for each species that compares the

outputs to inputs in terms of yield in kilos, calories, protein, fats, and carbohydrates separately.

These are then combined to assess efficiency in terms of the nutritional value of yield per time

unit of labour invested. Efficiency is calculated here as:

𝑌𝑖𝑒𝑙𝑑 (𝑘𝑔) × 𝑛𝑢𝑡𝑟𝑖𝑡𝑖𝑜𝑛𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 (𝑐𝑎𝑙𝑜𝑟𝑖𝑒𝑠, 𝑝𝑟𝑜𝑡𝑒𝑖𝑛, 𝑓𝑎𝑡𝑠 𝑜𝑟 𝑐𝑎𝑟𝑏𝑜𝑦ℎ𝑦𝑑𝑟𝑎𝑡𝑒𝑠/𝑘𝑔)

𝐿𝑎𝑏𝑜𝑢𝑟 (ℎ𝑟𝑠 𝑜𝑟 𝑖𝑛𝑠𝑡𝑎𝑛𝑐𝑒 𝑜𝑓 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦)

It is important to point out that the scale of production across each of the example

systems is different, but the creation of a simple ratio is argued here to be one technique that

diminishes this problem. A larger scale system such as that recorded for Tongatapu requires

more hours of labour to gain more outputs, while a smaller scale system such as that on Anuta,

which is that of a single family, requires fewer hours for fewer outputs. The calculated ratio is

assumed to be the same if production techniques and environmental limitations are the same.

One factor that does have to be considered is that the time unit for the Gadio Enga system was

recorded as ‘instances of activity’ rather than hours, and so the ratios are going to be skewed

towards an over-representation of outputs to inputs. Unfortunately, this cannot be avoided

within these comparisons. The results of ratio comparisons within each system will be noted

here, and overall patterning between systems discussed within the following section. The ratios

for species in each system is compared to gauge the source of highest energy and nutritional

returns from labour investment in terms of calories, proteins, fats and carbohydrates. These will

also be considered in comparison to the direct yield ratios.

Yield ratio comparison across systems

The yield for each species varied dramatically across the different modern systems (see Table

8.38). Some systems such as Anuta and Ontong Java were consistently low-yielding in relation

to time invested, thus creating greater disparity across the systems for all species apart from

Cyrtosperma merkusii and Ipomoea batatas. The overall greatest difference in yield was that

observed for Colocasia esculenta. The highest yielding system for this species was the Gadio

Enga, producing an output ratio of 66.1kg per instance of activity, while the lowest yielding

system, Ontong Java, produced only 900g per hour. Similarly, Artocarpus altilis yielded

41.7kg/hr within the Bellona system, but only 1kg/instance of activity within the Gadio Enga

and 500g/hr within the Anutan production system. Likewise, in assessing the yield ratios for

Cocos nucifera, there is a big contrast between the high ratio observed within the Bellona

system (30kg/hr) and the low ratio within the Ontong Java example. Many species only had one

196

yield ratio due to the lack of data from other systems. These include: Amorphophallus

paeoniifolius, Spondias dulcis and Zingiber zerumbet.

The Bellonan and Tongan systems often had similar high yield ratios as both are raised

limestone islands. All of the main Dioscorea yams were relatively high yielding in comparison

to labour inputs in the Bellona and Tongan production systems, ranging from 12.14-12.69kg/hr,

but had very low ratios in the Gadio Enga system. Similarly, both Musa sp. had yield ratios of

21-25kg/hr, compared to 9.6kg/h in Ontong Java, 5.7kg/instance of activity in Gadio Enga, and

only 0.6kg/hr in the Anutan system. Alocasia macrorrhiza was only present in the Bellona and

Tongan systems, and had similar yield ratios, 5.48kg/hr in the Bellona system and 6.3kg/hr in

the Tongan system. One of the only species for which these systems had radically different

ratios, was Ipomoea batatas. The Tongan system produced a yield ratio of 15.3kg/hr, while the

Bellona system only produced 3kg/hr. Similarly, Dioscorea bulbifera, commonly a naturalised

yam species, was produced in the Tongan system at 12.1kg/hr, while in the Bellona system only

3kg/hr was produced. It should be noted that the ratio within the Tongan system was calculated

based on the same yields for all yam varieties, while the Bellona system has specific figures for

each Dioscorea species.

Table 8.38 Yield ratios for archaeological species in all modern production systems (kg/time unit of labour)


In the Gadio Enga production system, the species providing the highest output to input return

ratio in terms of calories was Colocasia esculenta or the common taro (see Table 8.39). This

cultigen had a ratio of 87,609.2kcal/instance of activity (ioa), while the next highest ratio was

Species Gadio Enga Bellona Is Anuta Tongatapu Ontong Java

Alocasia macrorrhiza 0.0 5.5 0.0 6.3 0.0

Amorphophallus paeoniifolius 0.0 2.9 0.0 0.0 0.0

Artocarpus altilis 1.0 41.7 0.5 0.0 0.0

Cocos nucifera 0.0 30.0 0.0 0.0 0.5

Colocasia esculenta 66.1 5.5 1.5 8.9 0.9

Curcuma longa 0.0 0.0 0.0 0.0 0.0

Cyrtosperma merkusii 0.0 0.0 1.1 0.0 1.6

Dioscorea alata 0.3 12.7 0.0 12.1 0.0

Dioscorea bulbifera 0.3 2.9 0.0 12.1 0.0

Dioscorea esculenta 0.3 12.7 0.0 12.1 0.0

Dioscorea nummularia 0.3 12.7 0.0 12.1 0.0

Inocarpus fagifer 0.0 0.0 0.0 0.0 0.0

Ipomoea batatas 16.6 3.0 0.0 15.3 25.7

Musa sp.1 5.7 21.4 0.6 25.1 9.6

Musa sp.2 5.7 21.4 0.6 25.1 9.6

Piper methysticum 0.0 0.0 0.0 0.0 0.0

Solanum tuberosum 0.0 0.0 0.0 0.0 0.0

Spondias dulcis 0.0 83.3 0.0 0.0 0.0

Zingiber zerumbet 0.0 0.0 0.0 0.0 0.0

Average 5.1 13.5 0.2 6.8 2.5

197

that from Ipomoea batatas with 15,746.2kcal/ioa. Musa spp. had the highest ratios for arboreal

species within the system, with 6507.7kcal/ioa. Another arboreal tree crop, Breadfruit or

Artocarpus altilis had a ratio of 826.5kcal/ioa. Most of the Dioscorea yams ranked relatively

low in comparison to these other cultigens, with ratios of 433.7kcal/ioa. The lowest overall

calorific gain compared to labour investment was Zingiber zerumbet, which had a ratio of only

12.9kcal/ioa. These ratios also closely match the highest yield ratios for the Gadio Enga system.

The ratios for proteins, fats and carbohydrates follow much the same patterning and

distribution as those for calories and overall yield. Clearly, the varying nutritional values for any

of these species were insufficient to change the high-low distribution of ratios within the

system. The distributions of values were largely dictated by the large differences between the

yield and yield ratios for each species. Low ratios indicate that the production of species such as

Dioscorea yams and Z. zerumbet is relatively inefficient, with low returns for time invested.

These are gathered species and most likely require time for searching and harvesting that does

not provide efficient returns compared to that produced from horticulture or even ‘silviculture’.

In contrast the production techniques for species such as Colocasia esculenta and Ipomoea

batatas within the Gadio Enga system are highly efficient, as significantly greater gains are

made in terms of yield and associated nutritional values, for less time invested.

It is interesting to note that when these figures are compared with some other Highland

PNG ethnographic datasets, the efficiency of some crop production is almost reversed. For

example, within the Modopa (Waddell 1972) sweet potato (Ipomoea batatas) production has an

output to input ratio of 8,075kcal/hr, while Dioscorea alata yams have a ratio of 10,258kcal/hr.

These figures are lower and higher (respectively) than those calculated for the Gadio Enga, and

reflect a primary focus on sweet potato production using large plano-convex mounding within

open fields that are very rarely fallowed. Less time is invested in yam production within similar

mounds in mixed gardens, but the calculated yield per hour is higher than that for sweet

potatoes. In a Lowland PNG example, the Oriomo (Ohtsuka 1983) focus on sago production

(2,000kcal/hr), with the horticultural production of other crops (980kcal/hr) primarily

maintained to provide stability to the seasonal food supply. Chance shortages of sago was

compensated by other staples from the gardens, both enriching diet and stabilising supply

(Ohtsuka 1983:121). Wild plants only contributed seasonally to diet and in small amounts. Meat

from hunted animals contributed around 67.1% of protein and 4.3% of energy, with an average

of 25 minutes per day per capita dedicated to hunting compared to 118.8 mins for sago and 92.1

mins for horticulture (Ohtsuka 1983:119-18).

198

Table 8.39 Output to input ratios for archaeological species using Gadio Enga data


The highest yielding species for time invested in production in the Bellona system was Spondias

dulcis (see Table 8.40). However, the nutritional output ratios suggest that this species would

not necessarily have been preferentially cultivated or harvested over others within the system.

This yield ratio is most likely the result of seasonal harvesting of this species from areas close to

the village, so only a small amount of time is invested in searching, but high yields are gained

for the time that is invested (Christensen 1975). While still high compared to many other species

in the Bellona system, S. dulcis did not have the highest ratios for calories, proteins, fats or

carbohydrates. The species with the highest ratio for calorific gain over time invested was in

fact Cocos nucifera, with a ratio of 127,651.3kcal/hr, followed by S. dulcis with a ratio of

36,416.7kcal/hr. Artocarpus altilis also ranked relatively high with a ratio of 34,375kcal/hr. The

lowest ranked species was Ipomoea batatas, which is interesting as this is a horticulturally

produced cultigen. This species had a ratio of only 2,821.2kcal/hr— lower than the lowest

ranked semi-cultivated species, Dioscorea bulbifera, which had a ratio of 3,102.7kcal/hr.

The ratios for protein follow much the same pattern as that observed within the

distribution of calorific gain with the Bellona system. When the ratios according to fats are

assessed, there are some slight differences. Cocos nucifera remains the highest yielding species

with a ratio of 12960g/hr, followed by Spondias dulcis and Artocarpus altilis. However, within

the lower ratios there are some changes. The two species with the lowest fat ratios are

Amorphophallus paeoniifolius and D. bulbifera, two semi-cultivated species with ratios of only

Species Kcal/ioa Protein/ioa (g) Fat/ioa (g) Carbohydates/ioa (g)

Alocasia macrorrhiza 0.0 0.0 0.0 0.0

Amorphophallus paeoniifolius 0.0 0.0 0.0 0.0

Artocarpus altilis 826.5 25.5 9.0 190.3

Colocasia esculenta 87609.2 1124.0 231.4 20894.0

Curcuma longa 0.0 0.0 0.0 0.0

Cyrtosperma merkusii 0.0 0.0 0.0 0.0

Dioscorea alata 433.7 5.9 0.4 91.0

Dioscorea bulbifera 433.7 5.9 0.4 91.0

Dioscorea esculenta 433.7 5.9 0.4 91.0

Dioscorea nummularia 433.7 5.9 0.4 91.0

Inocarpus fagifer 0.0 0.0 0.0 0.0

Ipomoea batatas 15746.2 265.2 16.6 3331.6

Musa sp.1 6507.7 65.9 17.2 1565.3

Musa sp.2 6507.7 65.9 17.2 1565.3

Piper methysticum 0.0 0.0 0.0 0.0

Solanum tuberosum 0.0 0.0 0.0 0.0

Spondias dulcis 0.0 0.0 0.0 0.0

Zingiber zerumbet 12.9 0.4 0.2 2.6

199

1.8g/hr. Ipomoea batatas has a ratio of 3g/hr, which is just marginally greater than these two

species.

Ratios according to carbohydrates produce further changes in the distribution of low-to-

high ratios in the Bellona system. The highest gain in terms of carbohydrates is provided by A.

altilis, with a ratio of 7916g/hr. Despite having an average carbohydrate content of 5-10/100g in

comparison to other species within the system, C. nucifera still has the second highest ratio.

This indicates that the techniques used for the subsistence production as well as export of this

species were highly efficient, along with environmental suitability on the atoll (Christensen

1975). This species is followed by a number of horticultural root and tree crops that have high

carbohydrate content, such as most Dioscorea yams, Musa spp., Colocasia esculenta and

Alocasia macrorrrhiza. Ipomoea batatas had the lowest ratio of 596g/hr. When this figure is

compared to the high carbohydrate content of this species (20.1/100g), it could be argued that

the production of I. batatas within the Bellona system is not efficient in comparison with other

horticultural crops. In other words, to gain calories, fats, protein and carbohydrates to contribute

to daily diet with least time investment, I. batatas would not be the best selection in the

recorded Bellona system. A more obvious choice would be either C. nucifera or A. altilis.

Table 8.40 Output to input ratios for archaeological species using Bellona data


The recorded inputs and outputs for species in the Anutan system did not include many of the

archaeologically identified species from Tongatapu. Therefore, there are fewer species to

compare in terms of output to input ratios, with data available for only five crops (see Table

Species Kcal/hr Protein/hr (g) Fat/hr (g) Kg carbohydates/hr (g)




Cocos nucifera 127651.3 1305.0 12960.1 3150.0




Dioscorea alata 15189.4 261.4 10.2 2488.4





Ipomoea batatas 2821.2 47.5 3.0 596.9

Musa sp.1 24325.7 246.5 64.3 5851.0

Musa sp.2 24325.7 246.5 64.3 5851.0



Spondias dulcis 36416.7 666.7 250.0 3041.7


200

8.41). Of these, C. esculenta produced the highest ratios for most nutritional outputs, as well as

yield. This indicates that of these species, C. esculenta. was produced with the highest

efficiency in terms of returns for labour investment. This species had ratios of 1992.2kcal/hr,

8.5g/hr for protein, 5.3g/hr for fats, and 475.1g/hr in terms of carbohydrates. Likewise,

Cyrtosperma merkusii, another aroid, had relatively high ratios of outputs to inputs with 1365

kcal/hr and 222.9g/hr of carbohydrates.

On Anuta, Yen (1973b) notes that the trees and perennial species within the agricultural system

required the least attention during the cropping cycle, and in particular that bananas needed only

limited weeding, thinning and the creation of windbreaks. It is then interesting to note that Musa

spp. and Artocarpus altilis have lower yield and overall nutritional values than other staples.

There are some subtle differences in the efficiency of labour investment between two of

these core staple aroids, Colocasia esculenta and Cyrtosperma merkusii. Cyrtosperma merkusii

had relatively high ratios in terms of nutritional value apart from fats and protein, while C.

esculenta had the lowest ratios for all nutritional values. This may be because Cyrtosperma is

cultivated as a perennial species on Anuta, while a strict cycle of crop rotation is maintained for

common taro and manioc (Manihot esculenta) which also involves harvesting for storage. The

production of common taro is therefore more labour intensive, but apparently more efficient in

terms of yield and nutritional returns.

Table 8.41 Output to input ratios for archaeological species using Anutan data

Species Kcal/hr Protein/hr (g) Fat/hr (g) Carbohydates/hr (g)




Cocos nucifera 0.0 0.0 0.0 0.0









Ipomoea batatas 0.0 0.0 0.0 0.0

Musa sp.1 720.2 7.3 1.9 173.2

Musa sp.2 720.2 7.3 1.9 173.2





201

Tongatapu, Tongan Archipelago

The most efficient horticultural species within the Tongan system in terms of yield and

nutritional returns were Musa spp. (see Table 8.42). The production of these crops produced a

yield to time investment ratio of 25.11kg/hr, and the difference in yield ratios compared to other

species along with generally high nutritional values ensured that these crops also had high

nutritional ratios. The calorific gain for labour investment for both Musa spp. was

32,751.1kcal/hr, while protein was 331.8g/hr, fats were 86.5g/hr and carbohydrates were

7,877g/hr. There is a significant difference between these species and those with the next

highest ratios. Below Musa spp., the next highest ratios for calories, and carbohydrates were

those from all yam species. In terms of fats Colocasia esculenta and Ipomoea batatas had

higher ratios, while I. batatas also had a greater ratio for protein.

The least efficient species was consistently Alocasia macrorrhiza, which is not

cultivated as commonly as other aroids such as C. esculenta or Xanthosoma sagittifolium on

Tongatapu, according to the Agricultural Census (2001). Despite the size of the corms of this

taro species, the flavour is considered less palatable, processing time is longer, and this species

cannot be harvested as often as other varieties. It may also be the case that this aroid cannot be

grown as efficiently as other aroids using dryland techniques. Depending upon the nutritional

contribution needed by those cultivating and consuming these species, these differences in

efficiency could impact the decision to cultivate more or less of a particular crop, or changes in

the nature of labour investment through alterations to production techniques.

Table 8.42 Output to input ratios for archaeological species using Tongan 2001 data





Cocos nucifera 0.0 0.0 0.0 0.0




Dioscorea alata 15545.3 212.5 15.2 3260.9





Ipomoea batatas 14573.4 245.4 15.3 3083.4

Musa sp.1 32751.1 331.8 86.6 7877.6

Musa sp.2 32751.1 331.8 86.6 7877.6





202


Similar to the Anutan system, Ontong Java had very little data for most of the species identified

archaeologically on Tongatapu and therefore for this comparative exercise (see Table 8.43).

Despite this, some assessment can be made from the existing data upon the efficiency of these

crops in the Ontong Java production system. The species with the highest ratio for yield in terms

of time investment was I. batatas, and this species also had the highest ratios for calories,

protein, and carbohydrates. In terms of fats, the highest ratio was that from Cocos nucifera

(78.5g/hr), which was significantly higher than the next highest ratio, derived from both Musa

spp. (28.8g/hr). Both Colocasia esculenta and Cyrtosperma merkusii had roughly similar ratios

when compared to other species. This is because these two crops are often grown together in

freshwater swamps using similar techniques (Bayliss-Smith 1977:336). Although more land is

dedicated to the production of Cyrtosperma, the yield ratios are similar and Colocasia has

higher nutritional content in all values.

Table 8.43 Output to input ratios for archaeological species using Ontong Javan data

System efficiency comparison and system classification

When each of the archaeologically identified species are compared according to the ratio of

outputs to inputs in terms of calories, proteins, fats and carbohydrates across each of the modern

systems, it becomes clear that there are often significant differences (see Figures 8.22-8.25). As

highlighted earlier in the analysis of these efficiency ratios within these systems individually,

often the same patterning can be seen within all of the nutritional values. This patterning

indicates that there are no significant differences in the ranking of various nutritional values for





Cocos nucifera 773.6 7.9 78.5 19.1









Ipomoea batatas 24398.9 410.9 25.7 5162.3

Musa sp.1 10915.8 110.6 28.9 2625.6

Musa sp.2 10915.8 110.6 28.9 2625.6





203

species within these systems, and where there are changes in the ranking, the variances in values

are not significant enough to overcome the difference in overall yield ratios between species.

The consistency in patterning within output to input ratios can be seen within (Figures 8.22-

8.25).

Cocos nucifera or coconut provides an extreme example of these statistical differences

in efficiency of production at species level. Within the Bellona system C. nucifera has a ratio of

12.7kcal per hour, while within the Ontong Javan production system it has 0.7kcal per hour.

These differences are also reflected within other nutritional efficiency ratios for this species

within these systems. Clearly there is difference in the production techniques used by these two

systems. Ontong Java and Bellona both invested extra time into C. nucifera as part of a cash-

cropping initiative to supplement subsistence (Bayliss-Smith 1977; Christensen 1975), but this

labour input produced a much lower annual yield and associated calorific gain in the Ontong

Java system.

In another example, Artocarpus altilis or breadfruit produced much higher yield and

nutritional gain to lower labour inputs within the Bellona system (34,375kcal/hr, 1,062.5g/hr

protein, 375g/hr fat, 7,916g/hr carbohydrates) than either the Gadio Enga (826.5kcal/instance of

activity, 25.5g/ioa protein, 9g/ioa fat, 190.3g/ioa carbohydrates) or Anutan systems

(435.7kcal/hr, 13.5g/hr protein, 4.8g/hr fat, 100.4g/hr carbohydrates). These three systems are

based within very different environmental contexts. Bellona mostly consists of raised limestone,

while Anuta is a small volcanic island and the Gadio live in the New Guinea highlands. These

differing settings might partially explain the subsistence variation in nutritional efficiency ratios.

Similarly, Colocasia esculenta or the common taro produced a significantly higher yield

within the Gadio Enga system (87,609.2kcal/instance of activity) using dryland techniques than

any of the other systems, although this high ratio may be a result of the time unit used.

Interestingly, the dryland production of taro on Tongatapu and Bellona also resulted in the

generally higher output to input ratios of 11.827.6kcal/hr and 7,254.5kcal/hr, while wet

techniques on Ontong Java and Anuta resulted in much lower ratios of 1214.7kcal/hr and

1992.2kcal/hr. In support of this trend, while only two dryland systems had recorded outputs for

Alocasia macrorrhiza or the giant taro, the ratios from these were very similar. Within the

Bellona system the ratio for this species was 5,803.6kcal/hr (106.7g/hr protein, 8.2g/hr fats,

1,204.5g/hr carbohydrates), while that in the Tongan system was 6,674.4kcal/hr (122.7g/hr

protein, 9.4g/hr fats, 1,385.2g/hr carbohydrates) which is only marginally higher. Bayliss-Smith

(1977) argues that the Ontong Java subsistence prior to the cash-cropping of copra was based on

the production of taro, but the income generated by copra enabled the incorporation of new

imported goods into production and consumption patterns. This change may have heavily

impacted the efficiency of taro production on Ontong Java at the time this system was recorded.

204

Again, there are also differences in the environmental contexts within which these systems are

based, such as rainfall and geology, that will impact the efficiency of taro crop production.

The output to input ratios of these species were generally more similar across the

different systems. This was often the case for many of the aroids other than C. esculenta,

Dioscorea yams, Ipomoea batatas or sweet potato, and Musa spp. bananas or plantains. For

example, I. batatas had output to input ratios of 15,746.2kcal/instance of activity (265.2g/ioa

protein, 16.6g/ioa fat, 3331g/ioa carbohydrates) within the Gadio Enga system, 2,821.2kcal/hr

(47g/hr protein, 2.96g/hr fats, 596.9g/hr carbohydrates) within Bellona, 14,573.4kcal/hr

(245.5g/hr protein, 15.3g/hr fats, 3,063.4g/hr carbohydrates) within the Tongan system, and

24,398.9kcal/hr (410.9g/hr protein, 25.7g/hr fats, 5,162.3g/hr carbohydrates) within the Ontong

Java system. The highest of these ratios were recorded within the Ontong Java system, and in

this case I. batatas was grown within the village environs on a small scale along with several

tree crops. The overall similarities in ratios, compared to others within these systems, could

indicate that production techniques for sweet potato such as mounding, planting, harvesting and

storage are relatively equal in terms of efficiency across different settings and scales. In another

example, only two systems had recorded outputs for A. macrorrrhiza or the giant taro, but the

ratios from these were very similar. Within the Bellona system the ratio for this species was

5,803.6kcal/hr while that in the Tongan system was 6,674.4kcal/hr— only marginally higher.

Overall, the greatest similarity among the ratios was between the Bellona and Tongan

systems. These systems had ratios that varied only by 1000-3000kcal/hr for A. macrorrhiza, C.

esculenta, Dioscorea alata, Dioscorea esculenta, and Dioscorea nummularia, and varied by

8000kcal for both Musa spp. These systems share a number of environmental similarities, such

as a geological setting on a limestone raised island, and relatively consistent rainfall throughout

the year, allowing the utilisation of dry production of taro. Both cultures also attach high social

importance to the production of yams, and use similar propagation, planting and plant

maintenance techniques such as trellising (Christensen 1975; Ministry of Agriculture and

Forestry 2001).

The greatest difference in ratios was that between the Bellona and Anutan systems (see

Figure 8.26). While the species within the Bellona system had an average ratio of

24,155.6kcal/hr (353.2g/hr protein, 1,060.5g/hr fats, 2872.1g/hr carbohydrates), the Anutan

average was only 1,046.8kcal/hr (8.46g/hr protein, 3.14g/hr fats, 229g/hr carbohydrates). The

Anutan system consistently had the lowest ratios for each species within this system, indicating

that production techniques used within the mountain setting were generally inefficient in

comparison with those used within other systems. The highest ratios of outputs to inputs within

this system were those from Colocasia esculenta (taro) of 1992.2kcal/hr (8.5g/hr protein,

5.3g/hr fats, 475.1g/hr carbohydrates), suggesting that this was the crop that provided the

205

highest rate of return for lowest labour inputs. It is interesting that Yen (1973b: 139) asserts that

the Anutan system was in his subjective opinion, “…one of the most intensive extant in the

Pacific, despite the shortage of land and water, which could have conferred the potentiality for

the well-known form of intensive agricultural production, irrigation farming of taro.” Yen

(1973b) argued that the intensity of labour dedicated to agricultural production per hectare of

land on Anuta in comparison to the swidden horticulture of the Hanunoo of Mindoro in the

Philippines (3000/hectare versus 7000/hectare) supported this claim.

Based on the recorders’ own descriptions, these systems were classified as ranging from

mixed to shifting or intensive agriculture. However, as argued by Dornestreich (1977:247-8),

these terms are superficial and do not do justice to the full range of people’s actual subsistence

behaviour. Instead, a subsistence typology should include information upon a) the

environmental factors which substantially affect food getting, b) all the food-getting activities

which compose the people’s subsistence system, and c) all the foods obtained by these activities

in the form of a quantified account of food returns throughout an entire subsistence cycle

(197:248). This comparative study has attempted to assess these Western Pacific example

systems using these criteria, in order to provide a range of production systems within which the

potential systems archaeobotanically identified on Tongatapu can be considered.

The intensity of labour investment in particular crops, using various production

techniques that vary from cultivation through semi-cultivation to pure gathering of wild

resources, has been compared to the overall yield and nutritional returns. There are of course

limits to these data because of differences in what was deemed valuable by the recorders. Also,

comparison of the intensity of labour between systems is problematic as each example varies in

both scale and recorded time periods. Despite this, some descriptions can be made upon the

efficiency of these systems in relation to the diversity of species exploited. Overall system

efficiency was measured by dividing the total system efficiency by the number of species

utilised within each system to create an average ratio of outputs to inputs. Patterning according

to almost all nutritional values was the same, aside from carbohydrates (see Figure 8.26).

Diversity of species is categorised as low (0-14 species), moderate (15-19 species), and high

(20+ species). Yield ratio diversity is described as the difference between the average and

highest value for all species, and categorised as low (0-10), moderate (16-30), high (31+). These

systems can then be ranked in order of overall system efficiency and described as follows:

1. Bellona— high species diversity, insignificant nutritional diversity between groupings,

significant labour diversity between groupings, high yield ratio diversity.

2. Tongatapu— moderate species diversity, insignificant nutritional diversity between

groupings, insignificant labour diversity between groupings, moderate yield ratio

diversity.

206

3. Gadio Enga— high species diversity, insignificant nutritional diversity between

groupings, significant labour diversity between groupings, high yield ratio diversity.

4. Ontong Java— low species diversity, insignificant nutritional diversity between

groupings, insignificant labour diversity between groupings, moderate yield ratio

diversity.

5. Anuta— moderate species diversity, insignificant nutritional diversity between

groupings, significant labour diversity between groupings, low yield ratio diversity.

Figure 8.22 Output to input ratio comparison for archaeological species within each system in terms of calories

207

Figure 8.23 Output to input ratio comparison for archaeological species within each system in terms of protein

Figure 8.24 Output to input ratio comparison for archaeological species within each system in terms of fats

(note vertical scale is logarithmic)

208

Figure 8.25 Output to input ratio comparison for archaeological species within each system in terms of

carbohydrates

Figure 8.26 Comparison of average nutritional efficiency ratios for all systems (note vertical scale is

logarithmic)

209

Comparison of prehistoric production systems

The analysis of ethnographic examples from the Western Pacific has enabled the efficiency of

crop production in different environmental settings to be assessed and discussed. These systems

were ranked and described in terms of species and diversity of production technique

(horticultural, semi-cultivated, gathered), as well as the efficiency of labour investment in terms

of yield and nutritional returns. In this section the species identified within each of the

archaeological sites of Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2) will be firstly

compared to those species that have been ethnographically recorded within accounts of Tongan

agriculture at the point of European contact, and are expected to be able to be identified

archaeobotanically, in terms of overall nutritional value, labour and productivity. It was

expected that these comparisons could facilitate discussion of the completeness of these

systems, as well as system characterisation, when these are later compared to the Western

Pacific example production systems during the second component of analysis.

Nutritional comparison of archaeological species

Talasiu (TO-Mu-2)

All of the species identified in the microbotanical and macrobotanical remains from Talasiu

were compared and then ranked according to the same nutritional values discussed within the

modern production systems (see Figure 8.27). The calories, protein, fats and carbohydrates

within 100g of edible plant material from each archaeologically identified species were

compared, and an overall rank given out of 14, where a low number equalled a high nutritional

value. These species were then grouped into primary and supplementary species based on

ethnographic data and the most common categorisation of these species within the example

production systems.

Overall, Cocos nucifera and Inocarpus fagifer were ranked the highest and Piper

methysticum was consistently ranked the lowest. Aroids such as Colocasia esculenta tended to

be ranked high for overall nutrition figures (3rd), but varied from low to moderate ranking in

terms of individual nutritional figures. Artocarpus altilis had very similar rankings to C.

esculenta. The two remaining aroids, Cyrtosperma merkusii and Amorphophallus paeoniifolius,

both ranked relatively high according to calories (5th and 4rd), and A. paeoniifolius also ranked

high for protein (4th). With regard to fats, carbohydrates and overall nutritional figures these two

species tended to rank low or moderately. Of the two yam species, Dioscorea alata generally

ranks higher in all values than Dioscorea nummularia, which ranks very low (12th) according to

overall nutrition. Both Musa spp. were ranked high for overall nutrition (5th) and carbohydrates

(3rd), but ranked moderately according to calories, protein and fat. The two remaining

supplementary species, Spondias dulcis and Zingiber sp., both ranked low for overall nutrition

(13th and 12th) and most other values. The two exceptions to this pattern were that Zingiber sp.

ranked high (4th) and S. dulcis ranked moderately (7th) for fats.

210

When these rankings are compared according to the groupings of primary and

supplementary crops, some basic patterning can be determined. According to calories, the

primary crops rank slightly higher, with an average ranking of 5.7 over the supplementary

average of 8.3. The average rankings according to overall nutrition were almost exactly the

same, with 5.9 for primary crops and 8.6 for supplementary. Comparison of protein rankings

revealed that these two groups had almost equal averages of 7.4 within primary crops and 7.3 in

the supplementary. In terms of rankings for fat content, the supplementary species actually tend

to rank higher. These had an average of 6.3, while primary crops had an average of 7.6. Finally,

according to carbohydrates the primary crops again rank higher with an average of 6, compared

to 9.1 within the supplementary species. Overall these figures suggest that the primary crops

tend to rank higher than supplementary, which confirms the fact that these species would have

been given preference for cultivation.

Figure 8.27 Nutritional comparison of species identified at Talasiu (TO-Mu-2)

To gauge whether Talasiu could represent a complete system, a list of species was

developed from the ethnographic record of Tongan agriculture. This list was narrowed to

include only those species that contained starch, endocarp, fruit or vegetative storage

parenchyma that was likely to be processed and therefore enter the archaeological record at

Talasiu (TO-Mu-2). The species that were identified in the archaeobotanical record at Talasiu

were then compared nutritionally to these ethnographic species. When these two groups are

graphed, the exponential trend lines for both archaeological and ethnographic species follow

exactly the same curve (see Figure 8.28). When these two groups are compared statistically

Primary crops Supplementary

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Talasiu Nutritional Rankings

Rank kcalories

Rank protein

Rank Fat

Rank carbohydrates

Rank nutrition

Primary crops

Supplementary

Expon. (Rank nutrition)

211

using Student’s t-test, they cannot be differentiated, although the difference in averages is 43.06

(see Table 8.44). As to whether the species identified at Talasiu could represent a complete

agricultural system, the question needs to be posed: do these archaeological species represent

the best choices in terms of overall nutrition, and are they therefore more likely to be included in

the diet at Talasiu? This comparison would suggest that they are generally equal to the

ethnographic species in nutrition and so the results are inconclusive.

Figure 8.28 Nutritional comparison of species identified at Talasiu with expected ethnographic species.

Leka (J17)

The ranking of species identified at Leka within both microbotanical and macrobotanical

remains is compared in order to make suggestions about possible decision-making in terms of

preferential cultivation and consumption. Leka has some additional species added to the

provisions list compared to that of Talasiu, altering the rankings (see Figure 8.29). The highest

ranked species in most values was Cocos nucifera, followed by Curcuma longa or turmeric,

which is grouped here as a supplementary species according to ethnographic accounts of the use

of this crop. Following these was Inocarpus fagifer, another supplementary crop, which ranked

3rd in all categories apart from protein and carbohydrates, for which this species ranked 2nd.

Piper methysticum again ranked the lowest, followed closely by Spondias dulcis and Dioscorea

nummularia. In most cases the rankings closely resemble those seen in the archaeological

species identified at Talasiu, but would have lowered rank due to the high rank of C. longa. Of

the yams, Dioscorea alata no longer ranks the highest due to the inclusion of D. esculenta

which has higher nutritional rankings in all values apart from protein. A clear source of

contamination was Solanum tuberosum, which was identified in the microbotanical remains.

This species also ranks very low, aside from relatively high rank according to protein content

(7th).

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300

400

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Talasiu and Expected Ethnographic Economic Species Nutritional Comparison

Archaeological

Ethnographic

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Expon. (Ethnographic)

212

When these nutritional rankings are compared for the groupings of primary,

supplementary and contamination species for Leka, some patterning can be discerned. In terms

of calorific ranking, the primary crops rank slightly higher with an average of 7.8, while

supplementary crops have an average of 8.3. Primary crops also rank slightly higher than

supplementary species according to carbohydrates and overall nutrition, with average rankings

of 7.7 and 7.8 over 8.6 and 8.5, accordingly. Interestingly, the supplementary crops rank higher

than primary crops when the rankings for protein and fats are compared. In terms of protein,

supplementary crops have an average ranking of 7.3, while primary crops have an average of

9.4. Similarly, the supplementary crops have an average fat ranking of 7, while primary crops

have an average of 8.7. The contamination group ranks low compared to both groups in all

categories apart from protein, for which this group has a rank of 6th.

Figure 8.29 Nutritional comparison of species identified at Leka (J17)

As was the case with data from Talasiu, these species identified archaeologically at

Leka were then compared nutritionally to those species that would be expected to be identified

within the archaeobotanical record based on ethnographic accounts of Tongan agriculture (see

Figure 8.30). These two groups were compared using the overall nutritional figures from 100g

of edible plant material and graphed accordingly. The exponential trend lines for each were very

similar, although there was some divergence, suggesting that archaeological species may have

slightly lower overall nutritional value. However, when these two groups were compared

statistically using Student’s t-test distribution, they could not be differentiated with any

confidence (<50%). In fact, a comparison of the averages of these two groups provided a

difference in mean of only 5.47. This comparison would suggest that the archaeological species

Primary crops Supplementary Contamination

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Leka Nutritional Rankings

Rank kcalories

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Supplementary

Contamination


213

are almost exactly equal to the ethnographic species in nutrition and so the results are again

inconclusive.

Figure 8.30 Nutritional comparison of species identified at Leka with expected ethnographic species

Heketa (TO-Nt-2)

The species identified using archaeobotanical techniques at Heketa were compared using the

same nutritional values as those explored amongst species within the example production

systems (see Figure 8.31). This list of species was markedly smaller than those from Talasiu or

Leka, and so the rankings of species found at this site is different. As at Talasiu, the highest

ranking species was Inocarpus fagifer, which ranked first according to all nutritional values,

including overall nutritional figures. Piper methysticum also again ranked the lowest in all

values apart from fat, which is ranked 3rd. Similarly, Spondias dulcis ranked very low in all

values apart from fat, ranking 5th in this category. Of the aroids, Colocasia esculenta generally

ranked the highest, with high to moderate rankings according to all values. The remaining aroids

ranged from moderate to low ranking in all values, with a few exceptions. Alocasia macrorrhiza

ranked high according to protein value (5th), while Cyrtosperma merkusii ranked high in calories

(5th), and A. paeoniifolius ranked high in both calories and protein (4th). Ipomoea batatas is a

possible modern or historic contaminant, but was included within the primary species for

comparison, and ranks moderately according to protein (7th) and low in all other values. Only

one Musa sp. was identified at the Heketa, and this ranked low according to carbohydrates (3rd),

but moderately for calories, protein, fats and overall nutrition.

When these rankings are considered according to the grouping of species into primary,

supplementary or contamination species, the nutritional value of core cultivated crops in

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Species

Leka and Expected Ethnographic Economic Species Nutritional Comparison

Archaeological

Ethnographic



214

comparison with those that were most likely used on a more arbitrary basis can be assessed. In

most cases, the difference in average rankings between these two groups is minimal. Primary

crops were marginally higher ranked according to calories, with an average of 5.3 compared to

the supplementary average of 5.75. The average rankings for protein were exactly the same for

each group. Supplementary species ranked higher on average according to fat, with an average

of 4.7 over an average of 5.6 in the primary crops. This was the only category in which

supplementary species ranked higher than primary crops. The greatest difference between these

two groups was observed within the rankings of carbohydrate content. Primary crops had an

average ranking of 4.5, compared to an average of 7 within the supplementary species.

Contamination species were not included in this comparison as it was deemed unnecessary.

Figure 8.31 Nutritional comparison of species identified at Heketa (TO-Nt-2)

As a follow up to this nutritional analysis of archaeological species, these were then

compared to species that could possibly also have contributed to Tongan diet and subsistence

when Heketa was occupied (see Figure 8.32). The two groups again appeared to differ slightly

according to overall nutritional figures for 100g of edible plant material, when the exponential

trends are plotted on a bar graph distributing these species from highest value to lowest.

However, a statistical comparison of these groups using Student’s t-test revealed that these

groups cannot be differentiated according to nutrition (see Table 8.44, Table 8.45), despite an

overall difference in values of 0.82 pooled standard deviations and a difference of 55.21

according to mean. These results have once again proven inconclusive in discerning whether the

archaeological species could represent a complete system of nutritionally preferred species.

Primary crops Supplementary

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Figure 8.32 Nutritional comparison of species identified at Heketa with expected ethnographic species

Table 8.44 Statistical comparison of nutritional value of archaeological and expected ethnographic species

Table 8.45 Statistical comparison of nutritional value of species groups within archaeological systems at

Talasiu, Leka and Heketa

Efficiency comparison of archaeological species and production systems

The individual archaeological species from each of the sites of Talasiu (TO-Mu-2), Leka (J17)

and Heketa (TO-Nt-2) were combined into a list for each site, and then compared to the

efficiency ratios provided by each of the modern Western Pacific systems. The comparisons

enabled consideration of the efficiency (nutritional value of yield per time unit of labour

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Species

Heketa and Expected Ethnographic Economic Species Nutritional Comparison

Archaeological

Ethnographic



Archaeological site Pooled standard deviation Pooled standard error Difference Confidence Mean difference

Talasiu (archaeological vs

ethnographic) 175.0 67.8 0.6 <50% 43.1

Leka (archaeological vs

ethnographic) 173.7 67.3 0.1 <50% 5.5

Heketa (archaeological vs

ethnographic) 180.1 67.4 0.8 50% 55.2

Nutrition (total figures/100g)

Archaeological system Pooled standard deviation Pooled standard error Difference Confidence Mean difference

Talasiu (primary crops vs

supplementary species) 65.9 35.6 1.9 90% 68.9

Leka (primary crops vs

supplementary species) 61.4 32.3 0.1 <50% 3.9

Heketa (primary crops vs

supplementary species) 77.2 46.7 1.6 80% 73.2

All sites (primary crops vs

supplementary species) 41.1 19.9 0.3 <50% 5.9

Total nutritional figures (per 100g)

216

invested) of archaeological species in each site, and then an overall comparison of efficiency

that may reflect the level of labour intensity within each time period represented by these sites.

The species list from each site is here treated as a complete system, but as earlier data suggests,

this is unlikely to be the case. Nevertheless, this analysis will speculate about the categorisation

of these archaeological systems according to the spectrum provided within the modern

production systems. These past systems will be placed in the context of current hypotheses upon

the development of agriculture within Tongan prehistory in Chapter 9.

Inter-site comparison of species

Each species in each of the Tongatapu sites has already been assessed according to output to

input ratios that describe the efficiency of production techniques according to calories, protein,

fats and carbohydrates. In this section, the combined species list from each site will be broken

into the three groupings of primary crops, supplementary and contamination species and an

efficiency comparison conducted according to calorific gain for time invested. The intention

here is to model how these production systems may have functioned in the past, facilitating later

discussion of preferences for cultivation. Clearly all of these species were utilised in some form,

but which would have been staples? And how did these species enable the intensification of

production to create surplus for the development of social hierarchy? To answer these questions,

it is important to consider the ecology of agricultural systems in terms of context, inputs and

feedbacks, and how these systems evolved over time.

When the species identified archaeobotanically in test units from Talasiu (TO-Mu-2),

Leka (J17) and Heketa (TO-Nt-2) are compared in terms of calorific efficiency, some

suggestions can be made about crop preference (see Figures 8.33-8.35). Calorific efficiency

ratios were selected as a focus; as previous assessments have suggested that most other

nutritional value output to input ratios follow similar patterning. Of the 8 primary species and 6

supplementary species at Talasiu, Cocos nucifera has the highest average calorific efficiency

ratio (64,210kcal/time unit) from all of the systems. This was followed by Spondias dulcis,

primarily due to a lack of data from systems other than Bellona. Colocasia esculenta followed

these species, with an average ratio of 21,500kcal/time unit and had the highest ratios of the

aroids. Both Musa spp. had average ratios of 15,500kcal/time unit, just above Artocarpus altilis

with an average of 11,700kcal/time. Of the yams, Dioscorea alata has the highest ratio average

of 10,400kcal/time unit, marginally higher than Dioscorea nummularia which had an average of

9,800kcal/time unit. The only supplementary yam species, Dioscorea bulbifera, had a lower

average of 6300kcal/time unit. The two remaining aroids, Amorphophallus paeoniifolius

(3,900kcal/time unit) and Cyrtosperma merkusii (1.2kcal/time unit) both have very low

averages compared to C. esculenta. Zingiber zerumbet had the lowest average compared to all

other species, based on a single ratio of 1.3kcal/time unit from the Gadio Enga system. Two

species, I. fagifer and P. methysticum had no data available and so were not included.

217

Comparison of species at Leka revealed mostly similar distributions of average calorific

efficiency ratios. These species included ten primary crops, five supplementary species, and one

contaminant. Due to the inclusion of a few new species, some small ranking changes were

observed. For example, D. alata does not have the highest average ratio amongst the Dioscorea

yam species identified at Leka. Instead, D. esculenta, with a ratio of 10,400kcal/time unit has

the highest average. This mirrors the nutritional figures discussed earlier in this section. Several

species have no data from any of the systems, or are not particularly relevant as contaminants,

and therefore were not compared. These include Curcuma longa, Inocarpus fagifer, Piper

methysticum and Solanum tuberosum.

The list of species identified at Heketa is smaller than those from Talasiu and Leka,

with only seven primary crops, six supplementary and no contamination species. Of these the

top seven average ratios belong to species categorised here as primary crops. As at Talasiu and

Leka, Cocos nucifera has the highest average ratio at Heketa. The inclusion of another aroid

within this comparison changes the distribution amongst these taro species. Alocasia

macrorrhiza had a higher average than both A. paeoniifolius and C. merkusii, with a ratio of

6,200kcal/time unit. Ipomoea batatas is possibly contamination within this site, but as explained

earlier has not been classified as such here. This species has an average ratio that ranks between

Musa sp.2 and A. altilis. Zingiber zerumbet again has the lowest average ratio of all species

identified at Heketa. Three species had no data from any of the example systems and so could

not be included in this comparison, including Curcuma longa, Inocarpus fagifer and Piper

methysticum.

Statistically, the groupings of primary, supplementary and contamination species at

Talasiu, Leka and Heketa were not markedly different according to calorific efficiency ratings.

There was a difference in average of 7,100kcal/time unit at Talasiu between primary and

supplementary groups, 1,900kcal/time unit at Leka, and 5,800kcal/time unit at Heketa.

However, these groups could not be differentiated using Student’s t-test with any confidence

above 50% based on the average ratios from all of the example production systems, which is

unexpected considering the generally high averages of primary crops. When these ratios are

then averaged themselves, these higher figures tend to become smoothed out over the number of

species included in the comparison.

In light of this, it was deemed worthwhile to simply consider the ratios of primary to

supplementary crops within each of these archaeobotanical assemblages. Talasiu has a ratio of

1.3:1, while Leka has a ratio of 2:1 and Heketa is 1.4:1. These indicate exploitation of a closer

to equal range of economic and supplementary plant taxa at Talasiu, increased specialisation in

primary crops at Leka, and some diversification again at Heketa.

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Figure 8.33 Comparison of calorific efficiency of archaeological species from Talasiu

Figure 8.34 Comparison of calorific efficiency of archaeological species from Leka

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Figure 8.35 Comparison of calorific efficiency of archaeological species from Heketa

Efficiency comparison of past production systems

The overall system efficiency (in terms of calories) of these archaeological production systems

was calculated in the same manner as for the modern systems and compared. Species from each

of the sites of Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2) were combined into

individual site lists, and then averaged according to the calorific efficiency values of each of the

example production systems from Gadio Enga, Bellona, Tongatapu, Ontong Java and Anuta.

This comparison enabled some overall comparison of the efficiency of the archaeological

production systems from available data, if these systems are considered complete and resembled

modern systems (see Figure 8.36). Clearly, the ratios for species within the Bellona production

system were the most efficient in terms of calorific gain for time investment, while those from

Anuta were the lowest. Therefore, if any of the three archaeological systems represented by

archaeobotanical data at Talasiu, Leka or Heketa resembled the Bellona system, these would be

more efficient in terms of calorific gain than if they were similar to the Anutan system.

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Figure 8.36 Modelled archaeological systems according to calorific efficiency values from modern systems

In light of these comparisons, Chapter 9 will consider the descriptions of each of the

modern production systems in terms of species, nutritional, labour and yield diversity, as well as

the environmental context and production techniques utilised. These descriptions will be used to

predict the most appropriate models for archaeological production systems within this modern

range. These models will also be considered in the context of current hypotheses about the

antiquity of crop introductions and the subsequent development of agriculture in Tonga. It will

be argued that, due to the lack of data available upon variables such as acreage dedicated to

particular crops, scale of production, true labour investment, and dietary requirements of

individuals, modelling archaeological systems against a range of known examples using

Evolutionary and Human Ecological techniques can at least create new hypotheses upon the

nature of agricultural systems in the past. It is important to note that social production will not

be excluded from these models, as although this form of production is considered inefficient in

terms of basic nutritional returns, this is still visible within this analysis and can be used to

explain differences in productive efficiency between some species.

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Chapter 9 Discussion

This thesis sought to investigate the role of crops within colonising subsistence, as well as the

links between the production systems in which these crops are cultivated and the development

of social complexity in Tongan prehistory. With these aims in mind, the results of

archaeobotanical investigations at Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2) are

discussed here, focussing on modelling archaeological production systems. An agroecological

approach to the analysis of agricultural systems was made in Chapter 8, weighing the nutritional

costs and benefits of utilising particular plants in different environmental contexts. A scale was

created for species diversity, nutritional value, labour investment and intensity, and yield

diversity. Through this scale, the efficiency of both individual species and the system as a whole

could be assessed to provide known parameters to model archaeological production systems.

Chapter 8 provided the data and summarised patterning needed to be able to consider the most

appropriate descriptions of systems in the past, as well as highlighting limitations. These models

are placed in this chapter in the context of current hypotheses for Tongan and Western

Polynesian agricultural development. Further, the antiquity of crop use will be considered in

terms of the movement of people throughout the Western Pacific and also how crop use is tied

to the development of social complexity in Tonga, culminating in the emergence of the state-

level Tu’i Tonga paramount chiefdom.

Timing and nature of plant introductions into Tonga

The chronology of crop introductions into Tonga and the development of production systems

have been inferred through data from palaeoenvironmental research, linguistics and

ethnographic studies (Burley and Connaughton 2007; Fall 2005, 2010; Fall and Drezner 2011,

2013; Kirch 1997; Maude 1965; Thaman 1976). In terms of economic species, there has been

some conflict over the nature and timing of introductions due to differences in the information

derived from oral traditions and that from scientific botanical, linguistic, genetic and

archaeological research. Previous data and debates within Tonga and also the wider Pacific

region will be considered here to address the first of the research questions of this thesis

regarding the role of crops in the colonisation of the Pacific, alongside new data from the

current research at Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2) (see Table 9.1). These

data will be used to construct a new chronology for the timing of crop introductions into Tonga.

222

Table 9.1 List of all species identified archaeobotanically within this study

Spondias dulcis— Anacardiaceae

Botanical research has suggested that Spondias dulcis, known commonly as Otaheite apple or

vī, is probably native to the Indo-Malayan region, but was an ancient introduction in the Pacific

as far east as the Marquesas (Whistler 2009). This species has not been recorded in any previous

palaeoenvironmental research conducted in the Tongan archipelago (Fall 2005, 2010; Fall and

Drezner 2011, 2013), or archaeobotanical research elsewhere in the Pacific, and therefore the

relative timing of introduction to Tonga was not known. The presence of microbotanical

remains of the species in the form of unmodified starch residues within well-dated deposits at

Talasiu suggest that Spondias was introduced prior to 2750-2650 cal BP during the Lapita era.

Spondias is not completely naturalised within island landscapes, arguably due to the large fruit

which have no natural dispersers (Whistler 2009), and so would likely have been introduced as a

cultivated supplementary fruit which was a source of food and medicine. Its use was historically

documented by Cook (1785), La Billiardere (1793) and Waldegrave (1833). This species was

also present throughout at Leka and Heketa.

Alocasia macrorrhiza— Araceae

The giant taro or kape, is presumed to have been a prehistoric introduction into Tonga. This

species is probably native to tropical Asia or New Guinea based on current distributions of wild

species and subsequent cultivars which spread as far north as Hawaii and east to the Marquesas

(Matthews 2014; Purseglove 1972; Whistler 2009). There is currently no palaeobotanical

evidence for the introduction of A. macrorrhiza to any of the islands of Tonga. The earliest

evidence from other locations within the Pacific document this aroid in the Solomon Islands at

Family Species

Anacardiaceae Spondias dulcis

Araceae

Alocasia macrorrhiza

Amorphophallus paeoniifolius

Colocasia esculenta

Cyrtosperma merkusii

Arecaceae Cocos nucifera

Convolvulaceae Ipomoea batatas

Dioscoreaceae

Dioscorea alata

Dioscorea bulbifera

Dioscorea esculenta

Dioscorea nummularia

Fabaceae Inocarpus fagifer

Lecythidaceae Barringtonia asiatica

Moraceae Artocarpus altilis

Musaceae Musa spp.

Piperaceae Piper methysticum

Solanaceae Solanum tuberosum

ZingiberaceaeCurcuma longa

Unknown

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Kilu Cave by 28,000 BP (Loy et al. 1992), and north at Kosrae in Micronesia by around 1900

BP (Athens et al. 1996). Further east on Futuna, Piazza and Frimigacci (1991) documented the

presence of pollen deriving from A. macrorrhiza at around 600 BP. The earliest evidence for the

use of this cultigen in Tonga is dated to 800-600 cal BP from deposits within TP4 at Heketa.

Ethnographic descriptions of the cultivation of this species in plantations at the time of

European contact describe dryland production alongside yams, bananas, sweet potato and

coconut (Cook in Beaglehole 1969; Cook 1785; Mariner 1817). Around eight varieties are

recorded within Tonga that can be differentiated based on appearance (Maude 1965).

Consumption of the stem was preferential to the root and leaves, which were often used to

propagate new plants (Maude 1965).

Amorphophallus paeoniifolius— Araceae

Amorphophallus paeoniifolius is one of the least commonly cultivated aroids in the Pacific and

is known as elephant foot yam or more affectionately as the giant stink lily. The Tongan name

for this species is teve. Literature describes a larger reliance upon this species in the recent past,

but it is now utilised primarily as a famine food and is largely semi-cultivated or naturalised in

secondary forest and plantations (Purseglove 1972; Whistler 2009). Records of this species

within Tongan history are limited to one possible mention by Cook (1785:332), where he

describes “…a large root called ‘kape’, one not unlike our white potatoes called ‘mawhawha’;

the taro, or coccos of other places, and another called ‘jeejee’”. This could refer to the teve. A

later study noted the presence of Amorphophallus in bush allotments, but described these plants

as uncultivated and, according to informants, eaten only in times of famine (Thaman 1976).

Archaeobotanical investigations in this study have identified the presence of A. paeoniifolius at

all three sites, indicating that this species was introduced early by 2750-2650 cal BP during the

later stages of Lapita settlement on Tongatapu.

Colocasia esculenta— Araceae

The common taro is arguably one of the most versatile cultigens incorporated into the

production systems of the Pacific region. It can be grown in a variety of different climatic and

geological contexts, using wet irrigation or dryland shifting cultivation techniques (Kirch 1994;

Leach 1999; Spriggs 1996, 2002; Yen 1973a). It was thought native to Southeast Asia (Whistler

2009), but has been found within archaeological deposits in the Solomon Islands dated to

28,000 cal BP (Loy et al. 1992), at Niah Cave in Malaysia by 23,850-23,020 cal BP (Paz and

Barton 2007) and in Papua New Guinea by 10,220-6440 cal BP at Kuk Swamp (Denham et al.

2003), indicating that the wild progenitor of this species may have had a wider distribution than

was thought (Matthews 2014). The taxonomy and domestication of this species is also

complicated by the distribution of Colocasia formosana in Southeast Asia, a wild naturally

dispersed taro that is phenotypically close to C. esculenta (Matthews et al. 2015). Prehistoric

movement of C. esculenta into Remote Oceania is attributed to the Lapita Cultural Complex as

224

far eastwards as Western Polynesia and Polynesians are most likely responsible for initial

migration and subsequent adaptation of this crop to the diverse island landscapes of Central and

Eastern Polynesia.

The earliest evidence of Colocasia near Western Polynesia is at Bourewa in Fiji at

3050-2500 BP through starch grain, raphide and xylem tissue identification (Horrocks and Nunn

2007). Starch residues on pottery from Upolu, Samoa have been confirmed as common taro

within deposits dated to the Late Lapita occupation of the region by 2750 BP (Crowther 2009).

Starch, pollen and parenchyma of taro has been identified in many post-Lapita or late Holocene

deposits in Rapanui (Cummings 1998; Horrocks and Wozniak 2008; Horrocks et al. 2012 ),

New Caledonia (Horrocks, Grant-Mackie and Matissoo-Smith 2008), Kosrae (Athens et al.

1996), Mangaia (Kirch et al. 1995), Hawaii (Allen 1981, 1984), the Marquesas (Allen and

Ussher 2013), Pitcairn (Horrocks and Weisler 2006) and New Zealand (Horrocks and Barber

2005; Horrocks and Lawlor 2006; Horrocks, Smith, Nichol, Shane and Jackman 2008;

Horrocks, Smith, Nichol and Wallace 2008; Horrocks et al. 2004, 2007). Previous

palaeoenvironmental research in Tonga has identified pollen from Colocasia within swamp

cores from Vava’u and Eua dated to around 2600 BP (Fall 2005, 2010).In the current research

parenchyma and starch grains of Colocasia esculenta were identified in deposits from Talasiu,

Leka and Heketa. Results indicate that this crop was at least introduced into the Tongan

archipelago by 2750-2650 cal BP through Late Lapita migration and was utilised throughout

Tongan prehistory.

Cyrtosperma merkusii— Araceae

Native to Melanesia, it has been argued that Cyrtosperma merkusii or the giant swamp taro may

have been one of the first species cultivated in Remote Oceania by the Lapita settlers of the

region. The brackish conditions in beach back-swamps near many early Lapita settlements

would have enabled the initial cultivation of saline-resistant crops such as Cyrtosperma prior to

the establishment of more labour-intensive irrigation required for other aroids such as Colocasia

or Alocasia (Kirch and Lepofsky 1993; Yen 1973a, 1982, 1993). On atolls Cyrtosperma is

grown within various sized pits dug to access the freshwater aquifer (Weisler 1999), and so this

is another possible cultivation technique that would have enabled early settlers to survive on

raised limestone islands such as Tongatapu where traditional irrigation of common taro

(Colocasia) was impossible. The earliest evidence of Cyrtosperma within the Pacific is from

pollen dated to around 4500 BP in mangrove cores taken from Ngerchau region of Palau

(Athens and Ward 2001), although this may be due to natural distribution (Athens and

Stevenson 2012). Within Remote Oceania, starch, raphides and xylem tissues of giant swamp

taro was identified within Late Lapita-associated deposits from Urupiv in Vanuatu, dated to

around 2700 BP (Horrocks and Bedford 2004; Horrocks et al. 2014). Other evidence of

cultivation has been found in more recent deposits on Kosrae dated to 1997-1350 BP (Athens et

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al. 1996), the Pitcairn Group after 950 BP (Hather and Weisler 2000), and parenchyma on

Mangaia from 788-331 BP (Kirch et al. 1995). Microbotanical evidence for Cyrtosperma at

Talasiu, Leka and Heketa, represents the first recorded identifications of this species in the

Tonga. The presence of this taxa within deposits at Talasiu, a late Lapita-associated site,

indicate that this cultigen may indeed have been grown using the same pit agricultural

techniques observed in Micronesia until more intensive dryland techniques for other aroids and

yams were fully developed and this became a minor staple.

Cocos nucifera— Arecaceae

Cocos nucifera, known commonly as coconut or niu in Tonga, was often present prior to human

arrival due to dispersal of the large floating fruit on ocean currents, surviving up to 110 days

before husks become waterlogged (Gunn et al. 2011;Whistler 2009). It is undoubtedly one of

the most important cultivated species in the Pacific region, providing a source of water, food,

fuel, and numerous household items such as food storage vessels and thatch (Gunn et al. 2011).

The nutritional analysis of Cocos within this study points to the high calorific, protein, and fat

content of the mature meat, especially compared to other common cultigens. The only core

nutrient that this species lacks is carbohydrates, which is often provided by multi-cropping

cultivation with starchy root, tuber and tree crops in plantations. There have been some attempts

to associate the cultivation of coconut with Lapita settlement in Island Melanesia at Arawe

(Matthews and Gosden 1997), which may have actually been the result of beach drift, and more

confidently on Mussau from 3200-2000 BP (Kirch 1987, 1988, 1989). In Tonga, this species is

documented within pollen records prior to Lapita arrival but an increase in pollen quantities

around 2600 BP could indicate the cultivation of Cocos for food after this time (Fall 2005,

2010; Fall and Drezner 2011, 2013). The identification of charred endocarp deriving from

Cocos nucifera at Talasiu confirms this association, and continued cultivation is proven by the

presence of macrobotanical remains in deposits at Leka and Heketa, and also through many

ethnographic records (Beaglehole and Beaglehole 1941; Cook 1785; Gifford 1929; Orlebar

1830; La Billardiere 1800; La Perouse 1799; Mariner in Martin 1991; Waldegrave 1833; Wilson

1797).

Ipomoea batatas— Convolvulaceae

The cultivation of sweet potato (Ipomoea batatas), or kumala, is an important dryland crop in

Tonga. Ipomoea was listed as a major crop by Maude (1965), and was recorded within several

agricultural censuses (Ministry of Agriculture and Forestry 1985, 1994, 2001). The timing for

the introduction of this South American cultivar into Tonga is disputed. Two possibilities are

enabled within the ‘tripartite hypothesis’ proposed by Barrau (1957) and developed by Yen

(1974), Green (2005) and Clarke (2009). The first is that this species was an early Polynesian

introduction of plants within the ‘Kumara’ line from Central and Eastern Polynesia (Roullier et

al. 2013). The second possibility is that Ipomoea was a later introduction during the 18th or 19th

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Centuries by either Polynesians or Europeans, supported by Kirch’s research on Niuatoputapu

(1978, 1990). Genetic research does not provide much clarity in Western Polynesia (Denham

2013; Roullier et al. 2013). Early historic accounts clearly document the presence of this

cultigen as early as the late 18th century (La Billardiere 1793) and into the 19th century onwards

(Gifford 1929; Beaglehole and Beaglehole 1941; Waldegrave 1833). It is therefore most likely

that it was in fact a Polynesian import, and is supported by archaeobotanical evidence from

Eastern and Central Polynesia which documents the cultivation of Ipomoea on Mangaia from

around 950 BP (Hather and Kirch 1991), in the Marquesas by 750-350 BP (Allen and Ussher

2013), Hawaii at 650-325 BP (Horrocks and Rechtman 2009), Rapanui by 650-150 BP

(Cummings 1998; Horrocks and Wozniak 2008) and in New Zealand to the south by 704-550

cal BP (Horrocks et al. 2007). Considering these dates and the maritime connections of the

Tongan state, it is not unlikely then that Ipomoea batatas was present within the archaeological

system at Heketa from at least 600 cal BP, and is not a modern contaminant. Further, the

archaeological starch was also compared to that of beach morning glory (Ipomoea pes-caprae)

which grows near the sea, but did not match the morphology of that species.

Dioscorea spp.— Dioscoreaceae

Yams have played a very important role in Tongan agricultural and cultural practices

throughout prehistory. Three main named types are recognised ‘ufi tokamu’a (early yam), ‘ufi

tokamu’i (late yam) and ‘ufi lei (sweet yam), but there are many variants within each type. The

early yam and late yam have been botanically identified both as Dioscorea alata, while the

sweet yam is Dioscorea esculenta. During his third voyage Cook described these two species as

“The roots are yams of which are two sorts, one black, and so large, that it often weighs 20 to

30 pounds; the other white, and long, seldom weighing a pound” (1785:331-2). In 1643 Tasman

traded European goods for provisions for the ship from Tongatapu that included yams (Tasman

1776). Other species that have been ethnographically recorded are Dioscorea bulbifera which is

naturalised and the aerial bulbils are often used as a famine food (Waldegrave 1833; Whistler

2009), Dioscorea nummularia and Dioscorea pentaphylla, although these are less commonly

cultivated. Early ethnographers and missionaries commented on the importance of yams within

Tongan festivals such as the ‘inasi or first fruits festival, the tau tau ceremony, and pongipongi

feasting (Cook in Beaglehole 1969; Cook 1785; Gifford 1929; Mariner in Martin 1991). Others

noted the arrangement of yam crops within plantations, methods for cultivation, and annual crop

cycling. Cook (1785) specifically commented on the distinct layout and functional divisions

within individual plantations, as well as the differences between the produce reserved for the

chiefly elite and the commoners.

None of these Dioscorea spp. have been identified within palaeoenvironmental or

archaeological deposits within the Tongan archipelago prior to this study. The recovery of D.

alata, D. nummularia and D. bulbifera at Talasiu therefore provides the earliest evidence for the

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introduction of this genus into Tonga, and data from Leka indicates continued cultivation into

the Formative Period. The presence of D. esculenta in deposits dated to 800-600 cal BP at Leka

suggests that this may have been a later introduction, or is perhaps due to preservation bias. In

any case, the arrival of yams can only be securely dated to after this time within the Formative

Period. Elsewhere in the Pacific, the use of Dioscorea yams has been documented as early as

around 40,000 BP at Niah Cave in Malaysia (Paz and Barton 2007), and 10,220-9100 BP at Kuk

Swamp in PNG (Denham 2007). Lapita-associated use has been indicated by the recovery of

microbotanical remains identified as D. esculenta from Fiji and Vanuatu (Horrocks and Nunn

2007; Horrocks et al. 2013), and D. nummularia and D. pentaphylla also from Vanuatu

(Horrocks and Bedford 2010). Other evidence from Central and Eastern Polynesia support the

early transportation of these crops further into Remote Oceania. In fact, yams were transported

to each corner of the Polynesian Triangle as far as Hawaii in the north (Allen 1984), Rapanui to

the east (Horrocks and Wozniak 2008; Horrocks et al. 2012), and New Zealand in the south

(Horrocks and Barber 2005; Horrocks, Smith, Nichol, Shane and Jackman 2008; Horrocks,

Smith, Nichol and Wallace 2008). These place the findings of this study within the broader

Western Pacific context, and indicate that yams played an important role in Lapita and post-

Lapita subsistence.

Inocarpus fagifer— Fabaceae

The Tahitian chestnut or ifi, is cultivated as a supplementary species in plantations or found

naturalised in secondary forest. It is believed to have originated in the Indo-Malayan region and

has a current distribution as far east as the Marquesas (Walter and Sam 2002; Whistler 2009).

Early explorers and ethnographers recorded the presence of ifi in Tongan subsistence. One of

the earliest was La Billardiere who described the placement of and consumption of this species.

He wrote: “The sugar canes we saw there, were planted at a pretty considerable distance from

each other, under the shade of inocarpus edulis [polynesian chestnut], the fruit of which these

people roast and eat, its flavour much resembling that of the chestnut.”(La Billardiere

1793:366). Two other early ethnographers who recorded the cultivation of this species were

Gifford (1929) and Waldegrave (1833).

The earliest recorded evidence for the consumption of Inocarpus within the Pacific

region is from the Lapita-associated site of Mussau, where pericarp dated to 3200-2000 BP was

recovered (Kirch 1987, 1988, 1989). Very little further evidence for the prehistoric use of this

species has been found in archaeobotanical studies. Huebert (2014) recovered small quantities

of Inocarpus wood charcoal on Nuku Hiva in the Marquesas, associated with deposits dated

after the 17th century. In Micronesia, Inocarpus was identified on Kosrae by Athens and others

(1996) through parenchyma relatively dated to around 1900 BP. The identification of starch

from Inocarpus fagifer within this study is the first microbotanical evidence for the cultivation

of this food, and the first evidence for the introduction of this species into Tonga by 2750-2650

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cal BP. This species was present throughout the strata at Talasiu, Leka and Heketa indicating

that the nature of starch morphology and chemistry for this species facilitates high rates of

preservation. It is also possible that this supplementary species was more heavily relied upon in

the past.

Barringtonia asiatica— Lechythidaceae

The fish-poison tree or futu is not an introduced species to Tonga, having a native distribution

from Madagascar through to the Marquesas in the east in coastal stands of vegetation (Walter

and Sam 2002; Whistler 2009). It is not consumed, but rather the seed within the endocarp is

removed and grated to produce a pulp. The pulp is then mixed with sand and wrapped in leaves

before being placed in shallow areas of lagoons where there is little water circulation and fish

are forced to breach the surface to escape the effects of the poison. Fish are then caught easily in

nets (Whistler 2009). The species has only been recorded rarely in archaeobotanical

assemblages in the Pacific, and mostly within relatively recent deposits after 500 BP (Huebert

2014). Pollen records from Vava’u in Tonga have confirmed the presence of this species from

around 2600 BP in sampled marine clays along with Rhizophora mangroves, Thespesia

populnea, Guettarda, Cocos nucifera and Pandanus tectorius (Fall 2005). This

palaeoenvironmental evidence supports the identification of Barringtonia asiatica within

deposits at Talasiu and Leka from 2750-2650 cal BP. It is unlikely that starch grains of the seed

of Barringtonia entered the archaeological record at Talasiu through natural aeolian or hydraulic

processes, as the seed would need to somehow be exposed, dehydrate and then be abraded

enough to release reserve starch grains that were blown or washed into deposits. This suggests

that the species was being used for cultural and subsistence purposes (fishing) during late Lapita

occupation at least through to the Formative Period.

Artocarpus altilis— Moraceae

Artocarpus altilis is a domesticated variety of breadfruit or mei deriving from A. camansi

(breadnut) which is both wild and cultivated in New Guinea (Jones et al. 2012; Kennedy and

Clarke 2004). There is also hybridisation with Artocarpus mariennensis, endemic within

Micronesia (Ragone and Raynor 2009), cultivars from which may have also been distributed

across the Micronesian-Polynesian divide. Domestication processes, timing and spread of these

varieties is complex, and not yet fully understood. In Remote Oceania, Artocarpus altilis and A.

altilis X A. mariennensis hybrids are divided into two types, seeded and seedless cultivars.

Seedless varieties are taxonomically identified as A. altilis, and tend to be cultivated for

carbohydrates contained within the starchy fruit. Seeded varieties are either identified as A.

altilis or hybrids of A. altilis and A. mariennensis, and are often cultivated for both the flesh and

the seeds that are also a source of starch. Despite some varieties producing seeds, A. altilis is not

propagated through seeds, but rather from root and shoot cuttings from which seedlings are

produced (Ragone 2006). The geographic and chronological details of the development and

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spread of breadfruit remain to be fully investigated. (Jones et al. 2012; Kennedy and Clarke

2002)

Although the species does not play a prominent role within subsistence today on

Tongatapu, early ethnographic evidence suggests that this crop may have been much more

popular within plantations in the past (Beaglehole and Beaglehole 1941; Cook 1785; Gifford

1929; Orlebar 1830; La Billardiere 1800; La Perouse 1799; Mariner in Martin 1991; Tasman

1776; Waldegrave 1833; Wilson 1797). Dutch explorers La Maire in 1616 (1967 reprint) and

Tasman in 1643 (1776) observed that provisions they traded for included breadfruit, however it

was not as commonly grown as in the Society Islands. Cook (1785:272) describes the breadfruit

as the first food articles that his crew could purchase when they first arrived, and the trees

themselves were interspersed with little order alongside coconut and close to villages. La

Perouse in the 1780’s (1799:170) also described Tongatapu as having “…no trees; but such as

like the cocoa, breadfruit, that affords them subsistence”. Archaeobotanical evidence for the

cultivation of breadfruit has been found within a number of post-Lapita sites in Polynesia and

Micronesia. The starch, pollen, wood or exocarp parenchyma of this crop has been identified in

Kosrae (Athens et al. 1996), Society Islands (Kahn and Ragone 2013; Orliac 1997), Marquesas

(Allen and Ussher 2013; Huebert 2014), and possibly on Futuna (Piazza and Frimigacci 1991).

Prior to this study, there had been no palaeoenvironmental or archaeological evidence for the

cultivation of breadfruit in Fiji-West Polynesian prehistory. The recovery of starch and possibly

the storage parenchyma of the fruit of A. altilis at Talasiu indicate the species may have been

one of the initial Lapita crop introductions to Tonga. Further, the species was likely cultivated

throughout prehistory, as evidenced by small numbers of preserved starch grains at both Leka

and Heketa.

Musa spp.— Musaceae

Cultivated forms of the genus Musa are a complex, confused and confusing group, of great

importance in the Pacific and elsewhere. At least three distinctive lineages of cultivated bananas

have been described for Oceania, all of them with at least partial New Guinea ancestry.

Although biomolecular evidence has shown the complexities of these lineages, they are yet to

be distinguished in the archaeobotany of Remote Oceania (Kennedy 2008). They can be

difficult to differentiate taxonomically, and have therefore been simply classified as Musa spp.

within the reference collection and archaeobotanical identifications. The first domestication of

the Musa genus probably occurred within the Pacific region. The earliest evidence for possible

cultivation derives from Kuk Swamp in Papua New Guinea where phytoliths extracted from

archaeological deposits date to 10,200-6400 cal BP (Denham et al. 2003, 2004; Fullagar et al.

2006; Wilson 1985). There is also convincing evidence that Musa spp. were transported into

Remote Oceania by Lapita times. Starch and phytoliths from these crops have been identified

within Lapita associated deposits in the Reef Islands of the Solomons (Crowther 2009), and on

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Urupiv and Matilau in Vanuatu (Horrocks and Bedford 2010; Horrocks et al. 2009).

Furthermore, Musa phytoliths, pollen, endocarp and vegetative storage parenchyma have been

recovered in Eastern and Central Polynesia from a number of locations (Allen 1984; Horrocks

and Rechtman 2009; Horrocks et al. 2012; Kirch et al. 1995; McAllister 1933; Piazza and

Frimigacci 1991). The data from Talasiu, Leka and Heketa on Tongatapu fits well within this

chronology and distribution. But which particular lineages within the Musa genus were

cultivated by the Lapita settlers of Tongatapu and the Western Pacific, and transported

throughout the rest of Remote Oceania, remain to be established. Given the great diversity of

Oceanian cultivated bananas, it is quite likely that multiple movements , replacements and

accretions have contributed to this set of vital arboreal crops that are low maintenance but also

high yielding and are still cultivated today.

Piper methysticum— Piperaceae

The kava root is used throughout Polynesia and Micronesia as a relaxant often during traditional

festivals and rituals, and for medicinal purposes. It is thought to be native to Vanuatu where it

was first utilised and domesticated as a male clone of the endemic species Piper wichmannii

(Whistler 2009) before being transported east to West Polynesia and north to Micronesia. It is

solely propagated by hand through root and stem cuttings as populations outside of Vanuatu are

all male, which gives strength to the hypothesis that this species was anthropogenically-

introduced to all other islands in the Pacific where it is currently grown (Balick and Lee 2009).

Currently, there is no direct evidence for the timing of the domestication of kava within

Vanuatu, and the movement east. However, a number of studies support the hypothesis that this

may have occurred during Lapita settlement and interaction through analysis of ceramics that

resemble kava bowls and cups (Green 1974; Palmer 1968), linguistics (Geraghty 1983),

chemistry and biology of kava varieties (Lebot et al. 1997), and skeletal analysis of

temporomandibular joint (TMJ) degeneration that can be tied to kava preparation (Visser 1994).

Archaeobotanical evidence for kava cultivation and consumption has been recovered from late

prehistoric deposits in the Marquesas from 550-350 BP (Allen and Ussher 2013), and Hawaii

(Allen 1984) although a fossilised stem fragment belonging to a member of the Piperaceae

family has been identified in deposits associated with Lapita artefacts and dates to 3600-2400

BP (Kirch 1989).

Evidence from early ethnographic accounts point to the prominent role that this sedative

played in Tongan culture. Cook’s (1785) surgeon, Mr Anderson, commented that kava was

commonly planted about their houses, and that the root was the only part dug up for ceremonies.

Servants were observed breaking the roots into pieces, scraping the dirt off with a shell, and

preparing the mix (1785:318). Cook (1785:282) himself noted that on Tongatapu there was

“…hardly anywhere without the kava plant, from which they make their favourite liquor.” La

Billardiere’s crew (1793:339) were treated to a dinner of yams roasted in the fire embers and

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plantains, which La Billardiere assumed were to take the heat from the stomach produced by the

‘intoxicating liquor’ of kava. Furthermore, he describes “...its stalk, frequently bigger than the

thumb, is tolerably straight, and requires no support. They cut off several pieces in the spaces

between the knots, and they made us a present of them, informing us, that they set them in the

ground, in order to propagate the plant.” During the 1920’s Gifford (1929) observed that most

festivals and ceremonies involved the presentation of both food and kava to higher chiefs such

as the Tu’i Tonga or Tu’i Kanokupolu. One of the most detailed accounts of kava consumption

was published by Collocott (1927), where he describes the etiquette and placement of titled

individuals during kava ceremonies within a ‘kava-ring’. The careful distribution of roots is also

described in detail along with the methods for preparing the brew, with some comments on

modern adaptations of traditional practices. At least seven different types of kava are described

in terms of root size and how these are brought to these ceremonies.

Accounts and archaeological evidence from elsewhere in the Pacific are important for

assessing the nature of kava consumption in the past, and the timing of its introduction and

cultivation in Tonga. The microbotanical evidence from Talasiu (TO-Mu-2) suggests that this

crop was probably imported to Tonga during initial colonisation, but possibly in the latter part

of this period. This data ties in with current evidence suggesting late Lapita transportation of

kava out of northern Vanuatu during a period of interaction that facilitated the development of

the Proto-Polynesian language (Green 1966; Kirch 1989; Lebot et al. 1997; Visser 1994). The

presence of starch deriving from Piper methysticum within well-dated deposits at Leka (J17)

and Heketa (TO-NT-2), indicates the continued cultivation and incremental inclusion of this

crop within Tongan social practices. It is likely that the use of kava became tied to the

development of social hierarchy within Tongan prehistory, and was used to validate positions

within this hierarchy, as observed by Collocott (1927) and Gifford (1929) even after European

contact.

Curcuma longa and Zingiber spp.— Zingiberaceae

Members of the ginger family have played important roles in Tonga and the wider Pacific as

food items, but also for medicinal and domestic purposes. Most are thought to have been first

cultivated in Southeast Asia, but are now widely distributed throughout Melanesia, Polynesia

and Micronesia (Purseglove 1972; Whistler 2009). Curcuma longa or turmeric (ango) is

cultivated primarily as a dye for colouring tapa cloth or for body decoration. The methods for

processing the harvested roots varies throughout the Pacific, but generally involves some

washing, grating, straining, cooking and drying (Whistler 2009). There are only a small number

of ethnographic accounts that note the cultivation of turmeric in Tonga, including Cook (1785),

and Gifford (1929). Recent studies of Tongan agricultural production have noted the rare

presence of turmeric within allotments, often in a wild state, but protected due to the value of

the rhizome for the preparation of dye (Thaman 1976). It may be that this crop is preferentially

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cultivated closer to the village or within house gardens, rather than bush allotments. Other

varieties of ginger are not mentioned within early ethnographic accounts pertinent to Tonga, but

Zingiber zerumbet was recorded by Whistler (2009) during botanical survey. This particular

species of Zingiber was used as a shampoo, to add scent to tapa, and the sap could also be

drunk. There have been no recovered archaeobotanical remains of any plants belonging to

Zingiberaceae in the Pacific prior to this study. Here the vegetative storage parenchyma of the

rhizome of an unknown species within the Zingiberaceae family was identified in late Lapita-

associated deposits at Talasiu, and the starch of Curcuma longa was extracted from sediments at

Leka that can be dated to within the Formative Period of Tongan prehistory from 1300-1000 cal

BP. This evidence points to the use of members of this family within Tongan subsistence from

at least 2750-2650 cal BP, and continued archaeobotanical investigations on Tongatapu may

further elucidate the chronology of use for gingers in Tonga.

Modelling archaeological production systems

Each of these plant introductions in Tongan prehistory were either cultivated or utilised as

supplementary species in tropical production systems. The nutritional values and efficiency

(inputs vs. outputs) of each of these taxa extracted from the archaeological sites included in this

research (Talasiu, Leka and Heketa) were compared in Chapter 8. Here, these were combined to

characterise and discuss each of the archaeological production systems. These modelled systems

were used to address each of the two key research questions regarding the role of plants in the

subsistence of colonising populations in Tonga, and within the development of the social

complexity seen through evolution of the maritime chiefdom or state. Critically, it would appear

that modelled decreased system nutritional efficiency is linked to increased specialisation in

primary crops, observed through the ratios of numbers of primary to supplementary crops within

each of these archaeobotanical assemblages. Discussion will focus on how people may have

been cultivating or exploiting plants found in the archaeobotanical record, based on the context

of modern production systems, and also how changing system efficiency over time can be

linked to species diversification or specialisation.

Feasibility of modelling

Two main issues concern the feasibility of modelling archaeological systems, based on both the

data available and the approach used in this thesis research. It is important to address whether

the list of species identified in various micro- and macrobotanical remains at each site included

in this study might represent a ‘complete’ production system. Due to limitations in the faunal

data at all three sites, a full comparison with the protein dietary components was deemed

inappropriate. Further, without knowing the specific dietary requirements of the populations

occupying each of these sites in the past and the contribution of other food sources, it cannot be

calculated whether plant or animal species could have provided sufficient nutritional and

energetic benefits. These dietary requirements depend on the age, gender, and lifestyle of each

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member of the population, and therefore cannot be gauged from the limited data available at

Talasiu, Leka and Heketa. When these archaeological plant species are compared with other

ethnographically recorded species in accounts of Tongan agriculture, there is no statistical

difference in overall nutrition between the groups. This remains the case even when the list

restricted to only those species that are likely to be processed during food preparation and then

preserved in these archaeological deposits. Future analysis of modern soil samples from

agricultural systems to gauge the presence and quantity of plant microfossil and macrobotanical

material would enable greater accuracy in the analysis of plant inputs to outputs from

archaeological samples.

For each of the archaeological sites, statistical comparisons were made using overall

nutritional figures (combination of calories, fat, protein and carbohydrates within 100g of edible

material), and compared using Student’s two-sided t test and distributions. None of these were

statistically different with over 95% confidence and so the null hypothesis that these could have

been from the same population was unable to be rejected. These results are interpreted here to

suggest that there was no major nutritional advantage to be gained by choosing any of the

ethnographic species in addition to those found within the archaeological assemblages. So it is

plausible that these archaeological species could be viewed as composing ‘complete’ systems,

based purely on overall nutrition. Comparison of yield ratios may reveal a different patterning,

but this data is variable and is not available for all species. It would also be unlikely that all of

the ethnographically recorded species were introduced during initial settlement and were

therefore present throughout the Tongan sequence. The implication of this being that species

were most likely introduced gradually over time, and could feasibly be represented by the

ranges of species found archaeobotanically.

The second issue concerns the approach taken to modelling the archaeological systems.

It is argued here that an agroecological approach allows alternative hypotheses to be explored

through basic comparison of nutritional ranking, with overall system efficiency measured in

terms of the nutritional or energetic value of estimated yield (outputs) per unit of time invested

in labour (inputs). Using criteria that have been developed to describe a modern range of

ethnographic production systems from the Western Pacific, these archaeological systems were

characterised and modelled in terms of overall calorific efficiency (as assessment of individual

nutritional values revealed that patterning of system efficiency was generally equal) according

to predicted labour investment. This overall system nutritional efficiency was based on the

labour and yield data from the modern system that most closely resembled each archaeological

system, based on these characterisations.

The specific features of modern and archaeological systems explore a range of options

for labour investment and associated yield and nutritional return ratios that attempt to avoid the

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issues of geographic and temporal scale, breaking overall efficiency down into outputs per man-

hour for ease of comparison. Of course, this analysis does not provide any measure of social or

cultural benefits that require consideration of efficiency at the level of individuals. It is a purely

nutritional and energetic approach to productivity that explores decision-making through the

cultivation capacity of plants identified archaeologically based on a range of recorded and

described Pacific production systems.

Expected modelling outcomes

Based on current hypotheses for island colonisation and settlement, it was expected that this

modelling would indicate a pattern of developing complexity and intensity within production

systems over time from Talasiu (TO-Mu-2) (2750-2650 cal BP) through to Heketa (TO-Nt-2)

(800-600 cal BP). After weighing the arguments for Lapita subsistence, it is clear that the

‘strandlooper’ or solely marine-based forager-type hypothesis (Best 1984; Groube 1971) is

unlikely in light of current isotopic, faunal, and botanical evidence (Horrocks and Bedford 2004,

2010; Horrocks and Nunn 2007; Horrocks et al. 2009, 2014; Kinaston et al. 2013; Kinaston,

Bedford, Richards, Hawkins, Gray, Jaouen, Valentin and Buckley 2014; Kinaston, Buckley,

Valentin, Bedford, Spriggs, Hawkins and Herrscher 2014; Valentin et al. 2010). Initial dispersal

of populations may not have involved the introduction of plants, but this quickly changed within

one or two generations. If Lapita subsistence strategies did involve some element of terrestrial

production, the question remains as to the degree of reliance on imported plants over any

endemic or native species, and how these plants were cultivated. The argument over mental

templates within colonising populations involving knowledge of wet taro production using

pondfield construction and irrigation has been discussed partly in Chapter 2 (Bellwood 2005,

2011; Kirch and Lepofsky 1993; Spriggs 1990, 1996, 2003; Yen 1973a). These arguments for

and against independent development of pondfield irrigation are mostly irrelevant when

discussing horticultural systems on Tongatapu. This raised limestone island is not suitable for

wet taro production and extensive dryland techniques were utilised instead. However, this

argument is worth considering in relation to the types of crops that may have been brought to

the archipelago and experimented with. These agricultural techniques may also have been

brought to Tonga and Samoa before moving out into Central and Eastern Polynesia after a

1500-year pause that saw the transition to Ancestral Polynesian Society. It seems unlikely that

independent innovation of pondfield irrigation occurred over and over throughout the Pacific,

and yet current archaeobotanical and archaeological evidence does not suggest that colonising

populations utilised these techniques until much later in historical sequences. Instead it has been

argued that early Lapita migration into Western Polynesia was initially supported by ‘broad-

spectrum’ subsistence strategies, as defined by Ingold (2000) and Kennedy and Clark (2004)

utilising both cultivation systems and marine-based technology (Hunt 1980; Kirch 1978:12).

With regard to Tonga specifically, Burley (1998; Burley and Dickinson 2001) agrees, promoting

Kirch’s (1994) refined definition of a middle ground position, whereby agricultural activities

235

were initially of secondary importance and possibly limited to low energy swidden-type

cultivation.

The arguments generally depend on the timing and speed of the migration from Near

Oceania into Remote Oceania. New data from Bayesian analysis of radiocarbon dates from the

Bismarcks, Fiji and Vanuatu suggests that there was only a pause of around 130-290 years from

3360 to 3240BP in this eastern end of Near Oceania before colonisation began in Island

Melanesia and Western Polynesia by 3250-2900 BP (Denham et al 2012:44; Sheppard 2011).

New data from Tonga indicates the archipelago was also first colonised relatively quickly

around 2900-2800 (Burley et al. 2015). This relatively fast migration might suggest that

agricultural techniques such as pondfield irrigation would not necessarily provide an advantage

within subsistence practices at this early stage of colonisation. Causal factors such as population

growth and environmental change are unlikely to have forced the adoption of labor-intensive

techniques within such a short time frame.

One ecological approach attempted to operationalise migration episodes through the

Ideal Free Distribution (IFD) concept. Kennett, Anderson and Winterhalder (2006) used this

technique to account for modes of subsistence, new habitat suitability, and population density in

predicting migratory behaviour in the colonisation of East Polynesia. The concept predicted a

‘leap-frogging’ type of behaviour, with periodic episodes of migration followed by population

growth. Modes of subsistence are seen as the key variable influencing population growth and

environmental or habitat variability. For example, low level and later intensive food production

contributed to faster decreases in habitat suitability through environmental degradation, but

concurrently increased the overall carrying capacity of many remote island habitats (Kennett et

al. 2006:268). Overall the archaeological data from Oceania is argued to be consistent with the

predictions of the IFD model, with the long interval between the initial settlement of Near

Oceania at around 35,000 BP and movement in to Remote Oceania at around 3300 BP matching

the curve for foragers living on large islands (Kennett et al. 2006:285). Further, the rapid

migration into Remote Oceania after the colonisation of Western Polynesia is consistent with

the predicted curves for food production on small islands, while the intensification of these

systems can be viewed as an implication of the 1500-year pause here before later migration into

East Polynesia.

Considering these arguments, it was hypothesised that the Late Lapita production

system at Talasiu, several hundred years after initial settlement, would most likely have

resembled ‘broad-spectrum’ subsistence. This system would be characterised by high species

diversity including a number of both supplementary native and introduced species as well as

known Lapita cultivated cultigens such as a range of aroids, yams and tree crops. Production

techniques would focus predominantly on multi-cropping annual and perennial species that

236

would provide short-term returns for labour investment. Arboriculture would probably still play

a small role in this system and would have low efficiency in terms of yield and nutritional

benefits from labour investment. The comparative ethnographic system that best matches this

description would be the Gadio Enga production system, which utilises plants within a number

of agro-ecosystems that range from fully cultivated or managed to just simply gathered native or

naturalised species.

Looking beyond Late Lapita subsistence at Talasiu, the timing of occupation at Leka

(J17) represents settlement of the area during the Formative Period from around 1300-1000 cal

BP. Due to a lack of archaeological or archaeobotanical data, nothing is known about the role of

plants within subsistence strategies at this time. There is no evidence that the integrated

maritime Tu’i Tonga chiefdom had yet emerged, and the monumental architecture associated

with this chiefdom had not yet been constructed. The use of the phrase ‘the Dark Age’ for this

period by Janet Davidson (1979:94-5) is still relatively accurate, as the disappearance of pottery

after 1500 BP has meant that little is known about the nature of local cultural developments

until around 1000 BP (Burley 1998). Sites become both difficult to find and define. Limited

material remains from excavated sites suggest relative continuity between the Plainware and

Formative Periods; however, faunal data from Niuatoputapu indicate less reliance on marine

resources and increased production of pig (Kirch 1988). Data that has been correlated to the end

of the Formative Period point to an expansion of earthen burial mound construction, probably

associated with population growth (Burley 1998; Spenneman 1989).

Archaeobotanical remains from occupation at Leka reflect subsistence technology

influenced by concepts brought with the Lapita colonisers or through later migration and

interaction, and also by local development. It is clear that the fragile ecological composition of

islands, in conjunction with their insularity, makes them environmentally dynamic and

susceptible to any change. In an ongoing dialectic between environmental-human-climatic

factors, modes of subsistence are both created and restricted by environmental and social factors

within this dynamic ecological setting. Leppard (2014:10) has argued, however, that

environmental thresholds may not be the most valuable concept for visualising carrying capacity

early on in island sequences, but rather culturally-created thresholds that may have been

crossed. Pressure on food resources required innovative ways of alleviation, such as expansion

to new niches, intensification of food production systems or new modes of distributing

resources (Leppard 2014:10). Modes of distribution are argued by many Pacific researchers to

also include exchange networks within and between island groups (Green 1987; Kirch 1987,

1997; Summerhayes 2000; Terrell 1989). Unfortunately limited archaeological evidence during

this post-Lapita period in Tonga makes the association of subsistence practices with cultural

development difficult. Interaction was frequent in early and late phases of Tongan prehistory,

suggesting that this also the case in the ‘Dark Age’. It can only be assumed that any changes

237

that occurred paved the way for the subsequent development of the classic Tu’i Tonga

chiefdom, and multi-tiered social hierarchy (Davidson 1979). All of these environmental and

cultural factors, as well as those transported mental templates for production strategies already

discussed, would have characterised the form and flexibility of production at Leka.

With these factors in mind, it is likely that subsistence during the post-Lapita Formative

Period was characterised by continued experimentation with introduced cultigens, some

intensification of production to cope with environmental, social or demographic factors, and

further exploitation of natural resources. Studies of environmental change on Tongatapu have

pointed to a gradual drawdown of sea level from the mid-Holocene hydro-isostatic highstand

that would have drastically changed the shoreline of the Fanga’ Uta Lagoon (Dickinson 2001,

2007). The changing lagoon environment impacted the extraction of resources from this inshore

ecosystem, and is argued to have resulted in a significant decrease in the size and variability of

faunal marine species, particularly shellfish, through over-exploitation (Grono 2012). This

change was particularly clear in cultural deposits from Leka TP4 (Grono 2012). Clearly, there

was a change in the focus of subsistence from the marine to the terrestrial environment based on

previous evidence from occupation at Leka and other sites dated to the Formative era in the

Tongan archipelago.

The background to subsistence and cultural development at Leka would suggest that the

production system represented by archaeobotanical data from this site would have high species

diversity through continued periods of interaction and migration. This expansion of the

economic plant repertoire on Tongatapu should also correlate with significant nutritional

diversity between primary and supplementary crops. Continued experimentation with

production techniques suitable for the Tongan environment involving both new and established

cultigens would have resulted in increased overall efficiency in terms of energy and nutritional

returns, but would also have increased labour diversity between staple and other crops. For these

reasons, it was expected within this study that the archaeological production system evidenced

by cultural deposits at Leka would most likely resemble the Bellona system. This system was

characterised by shifting dryland cultivation with some intensive production for the cash-

cropping of copra, supplemented by the exploitation of supplementary species.

The final phase of Tongan prehistory, represented by archaeobotanical data from this

research, is the transition to a centralised maritime chiefdom which integrated the entirety of the

Tongan archipelago by at least 500 BP. Two deposits from test units at Heketa dated to around

800-600 cal BP and 600 cal BP, and fall into a period characterised by the development of

monumental architecture at Heketa as an early centre for chiefly political control (Clark and

Reepmeyer 2014; Spenneman 2002). At this later end of the Tongan sequence, subsistence is

argued elsewhere to have become more intensive or extensive to develop surplus to support the

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increasing socio-political complexity of the Tongan chiefdom (Aswani and Graves 1998; Clark

et al. 2008; Poulsen 1983, 1987; Spenneman 1989). Other proximal causes have also been

emphasised, such as environmental and demographic factors and warfare, but primacy has been

given to extensive and labour-intensive dryland food production strategies (Kirch 1984).

Modelling of agricultural dryland production and increasing population by both Green

(1973:69-73) and Kirch (1984:222) indicates that all of the arable land on Tongatapu could have

come under production by AD 1000 or possibly earlier. The timing of this ceiling on the

availability of land is argued to coincide with the amalgamation of local control into a central

polity on Tongatapu, and the beginning of a period of maritime expansion that extended Tongan

influence as far afield as Fiji, Samoa, Niue and Futuna (Aswani and Graves 1998:144). In his

interpretive model, Kirch (1984) elaborated on Green’s (1973) initial hypothesis of land

pressure triggering population control measures, arguing that population growth and

competition for land resulted in a series of regional chiefdoms that constantly assimilated

smaller groups to increase overall control and ended with the formation of a central polity on

Tongatapu. This was based on Carneiro’s (1970) hypothesis for state formation.

Correlation between the development of monumental architecture on Tonga and

emerging social complexity has also been drawn by a number of researchers. McKern (1929)

was the first to study this evolutionary confluence, and argued that the organisation of

manpower required to construct these stone platforms was the logical result of centralised

political and social power held by the Tu’i Tonga. Others have since expanded this hypothesis.

For example, Clark and others (2008) have argued that the change in form from non-sepulchral

architecture to large burial platforms at around AD 1450 coincided with the political integration

of the chiefdom under the 24th Tu’i Tonga, Kau’ulufonua 1, and reorganisation of titles into the

sacred (Tu’i Tonga) and the secular (Tu’i Ha’atakalaua). The transition to sacred chief began

with the move of power from Heketa to Lapaha by the 12th Tui Tonga, Talatama, but was

intensified by this further stratification. Oral traditions also link the 24th Tu’i Tonga to an

increase in territorial expansion to Uvea, Futuna and Samoa. Clark and others (2008) speculate

that at this crucial stage in the Tongan chronology an emphasis on the semi-divine status of the

chiefly lineages resulted in an increase in social complexity through further stratification of the

political hierarchy, but also increased the risk of chiefs distancing themselves from practical

government and control. It can be postulated that the segment of the population providing the

manpower required for construction may have been unable to produce their own food, and so

surplus would also have been needed to feed these workers. Redistribution of food for this

purpose may have resulted in the emergence of the tribute system, although this is difficult to

prove.

More recently, discussion has centred on the nature and scale of interaction within

Western Polynesia and how this influenced developing social complexity. There is some

239

evidence for early interaction within this region during Lapita settlement and the development

of Ancestral Polynesian Society or more classic Western Polynesian culture (Best 1984; Burley

et al. 2011; Clark et al. 2014). Later in Tongan prehistory, further development of trade

networks may have both extended and reinforced Tongan influence within Fiji and Samoa

during the development of the maritime state (Clark et al. 2014). These long-distance political

and economic exchanges within the second millennium AD have been traced through the

sourcing of lithic material from state and pre-state contexts on Tongatapu, and post-ceramic

contexts from Samoa. Results indicated a non-local long-distance source for 66% of analysed

stone artefacts from Tongatapu, but predominantly local sources for the Samoan material.

Interarchipelago interaction was clearly a feature of early occupation on Tongatapu that

intensified with the development of stratified society. It was argued from this data that an

important consequence of social complexity was the establishment of new types of specialised

sites for the transmission of people, plants and materials (Clark et al. 2014).

The connection between expansion of horticultural production and social complexity is

supported by early ethnographic accounts of intensive cultivation practices and tribute systems

evident during the yearly pattern of festivals such as the ‘inasi or first fruits festival (Gifford

1929; Mariner in Martin 1991). Intensification of production arguably enabled the development

of political economies within other islands and archipelagos, such as Hawaii (Earle 1980, 1991,

2012; Graves et al. 2011; Kirch et al. 2012; Kirch 1994; Ladefoged and Graves 2008, 2011;

McCoy and Graves 2012), Futuna (Kirch 1976, 1984, 1994), and the Marquesas (Addison 2006;

Allen and Addison 2002; Allen 2010; Earle 1993; Rolett 1998). The transition from broad-

spectrum subsistence strategies to more labor-intensive dryland agriculture was not a simple

process. It required decisions and political control of land to change cultivation and processing

techniques which increase the availability of essentially lower-ranked and less efficient

resources. This was likely to be a response to the decreased availability of higher-ranked

resources in terms of nutrition and energy efficiency, sourced through hunting or gathering.

However, the pathway to agricultural development through agroforestry, arboriculture, irrigated

vegeculture, or rain-fed vegeculture depends on both environmental constraints and cultural

factors. Understanding the mechanisms of change during this transition through the

intentionality within varying levels of decision-making is critical, and is the means by which

these can be linked to the current chronology of migration and socio-political development.

With these discussions in mind, it is expected that the archaeological production system

at Heketa, if complete, would most closely resemble the analysed Anutan production system. It

is likely that plant production at this point focussed primarily on dryland crops such as taro and

yams that would produce the largest yields within short periods of time, but not necessarily the

greatest nutritional returns. Overall system efficiency would be lower due to the decrease in

species diversity, and the utilisation of labour-intensive methods for crop production through

240

shortening of fallow lengths and reduction of production areas, after an initial period of

expansion. Labour diversity between groupings of plants (primary or supplementary) would

therefore also have become significant.

In summary, the archaeological plant production systems represented by

archaeobotanical remains from Talasiu (TO-Mu-2), Leka (J17), and the Heketa (TO-Nt-2) are

expected to have been similar to those from Gadio Enga, Bellona and Anuta respectively. These

expectations were based purely on weighing current arguments of the nature and role of

subsistence within Late Lapita, Formative Period, and the monumental state. The expectations

are compared with the outcomes of modelling archaeological systems using an agroecological

approach to view these systems in terms of species, nutritional and possible yield diversity, as

well as labour efficiency considering outputs for crops, groups (primary or supplementary) and

the overall system.

Modelling Talasiu (TO-Mu-2)

The dense and expansive midden at the site of Talasiu (TO-Mu-2) represents a well-dated

snapshot of subsistence in the Late Lapita period through faunal, floral and artefactual material.

AMS dates from test unit TP2 have pinned the occupation of Talasiu to around 2750-2650 cal

BP based on short-lived charred endocarp extracted from throughout the unit. The narrow range

of all dates from these deposits suggests that the midden at Talasiu represents settlement on the

shoreline of the Fanga ‘Uta Lagoon for around 100 years or less. Talasiu is therefore not the

earliest dated site on Tongatapu, as the site of Nukuleka closer to the entrance of the lagoon has

been U/th dated to 2838±8 cal BP (Burley 2001a,b; Burley et al. 2015), but archaeobotanical

data from Talasiu can provide information about the early post-settlement phase of Tongan

prehistory. As the Lapita cultural complex evolved into Polynesian society, whose descendents

would later colonise Central and Eastern Polynesia, production systems played a major role in

facilitating this process. This vital transitional phase is reflected within the data from Talasiu,

and can be modelled using an ecological approach to production systems that considers the

range of utilised species, and the nutritional efficiency of these that would influence decision-

making regarding the types of production techniques engaged in cultivation, management or

opportunistic gathering practices.

The range of species identified within archaeobotanical remains from Talasiu TP2

represents a mix of arboreal species and root and tuber crops from a number of different

families (see Table 9.2). Only one of these taxa is considered endemic or native to Tongatapu,

and the remainder must therefore have been introduced by Lapita colonisers or their

descendents. Cocos nucifera has been found within pre-human deposits in pollen cores from

Avai’o’vuna Swamp on Vavau during a marine high-stand dated to 4500-2600BP (Fall 2010),

and likely arrived through the flotation of fruit upon marine currents. All but two of the

241

identified taxa are generally accepted to have been early prehistoric introductions into Tonga.

One exception is Ipomoea batatas, known more commonly as the sweet potato, which is a

known later introduction from South America via Eastern Polynesia that is suspected by some

researchers to even be a historic introduction (Kirch 1978, 1990), and was therefore classified as

modern contamination within this assemblage. The other is Piper methysticum or kava, which

some oral traditions in Tonga suggest was a late prehistoric export from Vanuatu, but has not so

far been corroborated with linguistic or genetic data. Considering this it has been included

within the list of species, primarily to keep an open mind about this crop in terms of the timing

of its introduction and the role this species may have played within production systems in the

past. There are also a number of species that have not previously been identified within Lapita-

associated deposits in Melanesia or Western Polynesia. These include the aroid Amorphophallus

paeoniifolius, the yam Dioscorea bulbifera, Inocarpus fagifer (Tahitian chestnut), Barringtonia

asiatica (Fish-poison tree), Artocarpus altilis (breadfruit), and Piper methysticum or kava.

Table 9.2 Identified families and species within archaeobotanical remains from Talasiu (TO-Mu-2)

Using the criteria derived from the analysis of production systems from the Western

Pacific, the archaeological production system at Talasiu (at least that based on those species

identified archaeologically) can be described and compared to this range of ethnographic

examples. Compared to this range of systems, Talasiu has moderate species diversity (15

species), and has insignificant nutritional diversity between groupings of ‘primary crops’ and

‘supplementary species’ (90% confidence). The labour and yield diversity of species within the

Talasiu system cannot be known. However, when these species are compared using the figures

from all of the example systems, a range of possibilities can be gauged. In the case of Talasiu,

the average yield ratios (see Table 9.3) within the archaeological system can range from low (0-

10) to high (31+) diversity, depending on the figures used. Despite large differences between

the average labour inputs for each grouping when these are modelled using the figures from the

Family Species


Araceae


Colocasia esculenta



Dioscoreaceae

Dioscorea alata

Dioscorea bulbifera





Musaceae Musa spp.


Zingiberaceae Unknown

242

example systems (see Table 9.4), these are not deemed to be statistically significant differences

when calculated using Student’s t-test (95% confidence or over based on the number of

compared samples). When modelled on the Bellona Island data, labour investment between the

two groups could be differentiated by 2.04 standard errors, but based on the number of samples

(degrees of freedom) the probability of samples or species being from the same group is 20%.

This probability does not allow rejection of the null hypothesis that these two groups could

belong to the same population based on mean difference (see Table 9.5). Under these conditions

the Talasiu system could be characterised as:

Talasiu— moderate species diversity, insignificant nutritional diversity between

groupings, insignificant labour diversity according to groupings, low-to-high yield ratio

diversity.

Based on this, the Talasiu system most likely resembled the production system recorded

on Tongatapu in 2001 in the Agricultural Census of that year. If this is the case then the average

calorific efficiency of this system is around 20666kcal/hr, with a total calorific efficiency of

123996kcal/hr (see Figure 8.36). When it is considered that the data from the 2001 Tongatapu

system was based on an intensive cash-cropping economy, this characterisation is unexpected. It

was expected that the Talasiu system would more closely resemble the Gadio Enga production

system, which was described as ‘mixed’ or ‘diverse’ by Dornstreich (1977) involving similar

labour investment into each species within a range of exploited agro-ecosystems, if late Lapita

subsistence fell somewhere between a ‘strandlooper’ and ‘transported landscape’ economy.

Using the comparative analysis carried out during this study, the Gadio Enga system was

characterised as having high species diversity, insignificant nutritional diversity between

groupings, significant labour diversity between groupings and moderate yield ratio diversity.

Clearly these do not match the description of Talasiu outlined here, and this discrepancy will be

discussed at the end of this section.

243

Table 9.3 Yield ratios for species identified at Talasiu modelled using comparative systems

Table 9.4 Labour inputs for species identified at Talasiu modelled using comparative systems

Table 9.5 Statistical comparison of labour inputs for groupings at Talasiu in terms of mean difference

modelled using comparative systems




Cocos nucifera 0.0 30.0 0.0 0.0 0.5



Dioscorea alata 0.3 12.7 0.0 12.1 0.0




Musa sp.1 5.7 21.4 2.5 25.1 9.6

Musa sp.2 5.7 21.4 2.5 25.1 9.6


Spondias dulcis 0.0 83.3 0.0 0.0 0.0

Zingiber zerumbet 0.0 0.0 0.0 0.0 0.0

Average 5.7 16.8 0.4 6.8 1.6

Grouping Species

Gadio Enga

(instances of activity)

Bellona Is

(hours/yr)

Anuta

(hrs/37 days)

Tongatapu

(hrs/yr)

Ontong Java

(hrs/yr)

Primary crops Artocarpus altilis 10.3 60.0 62.6 115.2 183.0

Cocos nucifera nd 3333.3 30.3 2317.4 202960.0


Cyrtosperma merkusii nd nd 18.3 nd 43830.0

Dioscorea alata 39.5 16683.0 0.7 21595.1 nd

Dioscorea nummularia 39.5 16683.0 0.7 8867.0 nd

Musa sp.1 30.1 9425.0 20.3 1404.4 183.0

Musa sp.2 30.1 9425.0 20.3 1404.4 183.0

Supplementary Amorphophallus paeoniifolius nd 854.1 nd nd nd

Dioscorea bulbifera 39.5 854.1 0.7 201.0 nd

Inocarpus fagifer nd nd 0.7 57.7 nd

Piper methysticum nd nd nd 2527.5 nd

Spondias dulcis nd 60.0 nd 5.0 nd

Zingiber zerumbet 30.1 nd nd nd nd

Average 31.1 6925.0 26.3 5275.0 48528.2


Gadio Enga (primary crops vs

supplementary) 9.3 7.6 0.6 <50% 4.9

Bellona Island (primary crops vs

supplementary) 5424.6 4429.2 2.4 95% 9050.8

Anuta Atoll (primary crops vs

supplementary) 13.4 10.6 0.9 60% 9.8

Tongatapu (primary crops vs

supplementary) 7192.8 4650.4 1.6 80% 7192.8

Ontong Java (primary crops vs

supplementary) 87899.2 0.0 0.0 0 0.0


244

Modelling Leka (J17)

The Formative Period (1500-1000 BP) led to the later development of a complex social

hierarchy in Tongan prehistory but the archaeological record is characterised currently by a

general lack of evidence for any cultural, political or technological change. With regard to

changes in subsistence strategies, few sites have been dated to this period, and fewer still have

been excavated to collect data on both faunal and floral components of diet. Occupation at Leka

(J17) is an important site to assess both these components in terms of the expansion of territorial

resource use, due to the decline in available near-shore marine species through overuse and

environmental change. The faunal remains from Leka have been analysed by Grono (2012) and

confirm that the hydro-isostatic drawdown of sea level after the mid-Holocene reduced the

availability of many larger shellfish species, prompting a gradual focus inland that is also

reflected within settlement patterns during this time (Poulsen 1967; Spenneman 1986, 1989).

The debate surrounding post-Lapita plant production systems, which has focussed on factors

such as mental templates, continued interaction and migration, environmental thresholds and

change, culturally-created thresholds, and demographic change, has already been outlined. It is

important to discuss early production at Leka, and how this compares with expectations based

on this contextual background.

The list of identified species in the micro- and macrobotanical remains from Leka again

includes a number of arboreal, root and tuber crops, as well as supplementary species that would

have been semi-cultivated or gathered from native or naturalised plants. As was the case with

species identified in deposits at Talasiu, these are mostly prehistorically introduced plants apart

from Cocos nucifera, and all but the White potato (Solanum tuberosum) are considered to have

been introduced prior to European contact. This species has been labelled as a contaminant in

samples from Leka that probably occurred during laboratory processing but this will be

discussed later in this chapter. Piper methysticum is thought to be a late prehistoric introduction,

and so is also possibly a contaminant within these samples, but as was the case for Talasiu, this

species will be incorporated as a supplementary species as it may be an early introduction.

Because so little is known about the Formative Period in Tongan prehistory, none of these

species have previously been identified within palaeoenvironmental or archaeological deposits

from this time, and therefore these contribute greatly to knowledge upon subsistence and the

role plants played in the evolution of social hierarchy and political economy.

245

Table 9.6 Identified families and species within archaeobotanical remains from Leka (J17)

The combined list of species from Leka was modelled as a complete plant production

system and compared with the range of modern production systems The same criteria used to

characterise modern systems were applied to the data from Leka, and used to gauge the extent

of species and overall system diversity and efficiency in terms of nutrition, yield and labour

inputs. There are limitations to this, as some plant data is not available for all modern systems,

but when these species are treated as a system, patterning emerges that at least eliminates some

modern systems and pinpoints others that are more likely similar to that at Leka. This system

has moderate species diversity in all primary and supplementary species (16 species in total),

but insignificant nutritional diversity between these groupings (<50% confidence). The labour

and yield diversity of species in the Leka system cannot be known. However, when these

species are compared using the figures from all of the example systems, a range of possibilities

can be gauged. The average yield ratios for species within the Leka system can vary from low-

to-high diversity (see Table 9.7), when modelled using figures from all of the comparative

systems. Average labour input figures for each grouping varied markedly between these

example systems (see Table 9.8), but most were not able to be shown to be statistically different

using Student’s t test and associated two-sided distribution. Labour diversity between the

groupings was only significant when modelled using data from the Bellona system (2.64

standard deviations and 95% confidence), but was followed closely by Anuta (0.86 standard

deviations and 90% confidence). From these descriptions the Leka system can be characterised

as:

Leka— moderate species diversity, insignificant nutritional diversity between

groupings, significant labour diversity, low-to-high yield ratio diversity.

Family Species


Araceae


Colocasia esculenta



Dioscoreaceae

Dioscorea alata

Dioscorea bulbifera

Dioscorea esculenta





Musaceae Musa spp.


Solanaceae Solanum tuberosum

Zingiberaceae Curcuma longa

246

The description of the Leka system, if the list of species identified archaeobotanically

within test units at this site are considered to represent a complete system, most closely

resembles the Anutan system. The data recorded and compared for the Anutan system suggested

that the utilisation of plants on this small high island involved a moderate number of species,

but when these were grouped into primary or supplementary species according to the nature of

their use and production there was no significant nutritional diversity between these groups.

However, there was significant diversity within labour inputs for each of these groups, which

differed by 3.17 standard deviations with 100% confidence. Overall yield ratio diversity was

low between species within the Anutan system. If this model is correct, then the overall

efficiency of the Leka system was 1268kcal/hr, which is the least efficient of all of the

simulated systems for Leka, and is significantly lower than Talasiu. This exercise in modelling

the archaeological production system at Leka does not meet the original expectations, which

suggested that this system would most closely resemble the Bellona system based on current

hypotheses for island colonisation and the role of agriculture in the development of social

hierarchy. If this model is correct, then the Leka system was probably more labour intensive

than originally presumed, and focussed on the cultivation of a narrow range of primary crops,

with little labour invested in the exploitation of supplementary species. The implications of

these findings will be discussed later in further detail.

Table 9.7 Yield ratios for species identified at Leka modelled using comparative systems




Cocos nucifera 0.0 30.0 0.0 0.0 0.5


Curcuma longa 0.0 0.0 0.0 0.0 0.0


Dioscorea alata 0.3 12.7 0.0 12.1 0.0


Dioscorea esculenta 0.3 12.7 0.0 12.1 0.0



Musa sp.1 5.7 21.4 2.5 25.1 9.6

Musa sp.2 5.7 21.4 2.5 25.1 9.6


Solanum tuberosum 0.0 0.0 0.0 0.0 0.0

Spondias dulcis 0.0 83.3 0.0 0.0 0.0

Average 5.0 15.5 0.3 6.7 1.4

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Table 9.8 Labour inputs for species identified at Leka modelled using comparative systems

Table 9.9 Statistical comparison of labour inputs for groupings at Leka in terms of mean difference modelled

using comparative systems

Modelling Heketa (TO-Nt-2)

The cultural deposits at Heketa have radiocarbon ages which place occupation at this site to the

Formative Period, and transitioning to the early stages of the Classic Tu’i Tonga chiefdom

initially based at Heketa before moving to south to Lapaha after the 14th century AD. Two

distinct cultural deposits were dated using AMS. Charred coconut endocarp from Layer 3 dated

to around 600 cal BP, while endocarp from Layers 4-5 produced a calibrated range of 800-600

cal BP. There is some overlap between these ranges, and so it is possible that these represent

either two discreet systems or events, or a continuity of site occupation and associated plant

production. When the ranges of identified species within these deposits are compared, there are

differences in the number and type of species present. Layer 3 has ten species including six

primary and four supplementary species. Layers 4-5 have seven species, which includes five

primary and only two supplementary species. Due to the possible overlap in dates and low

overall preservation of microbotanical remains within these deposits from Heketa TP4 that may

have biased the distribution of these identifications, it was decided to treat the list of species

identified within TP4 at Heketa as a single system for modelling. The data provides an

interesting insight into the type of production system that may have enabled the creation of

Grouping Species

Gadio Enga


Bellona Is

(hours/yr)

Anuta

(hrs/37 days)

Tongatapu

(hrs/yr)

Ontong Java

(hrs/yr)

Primary crops Artocarpus altilis 10.3 60.0 62.6 115.2 183.0




Dioscorea alata 39.5 16683.0 0.7 21595.1 nd

Dioscorea esculenta 39.5 16683.0 0.7 8867.0 nd

Dioscorea nummularia 39.5 16683.0 0.7 8867.0 nd

Musa sp.1 30.1 9425.0 20.3 1404.4 183.0

Musa sp.2 30.1 9425.0 20.3 1404.4 183.0


Curcuma longa nd nd nd nd 9200.0

Dioscorea bulbifera 39.5 854.1 0.7 201.0 nd




Zingiber zerumbet 30.1 nd nd nd nd

Contamination Solanum tuberosum nd nd nd nd nd

Average 32.0 7812.0 24.0 5574.4 42909.9



supplementary) 9.3 7.4 0.5 <50% 3.5


supplementary) 5565.9 3768.1 2.6 95% 9931.1


supplementary) 13.0 10.2 0.9 50% 8.7


supplementary) 7044.6 4313.9 1.7 80% 7314.9


supplementary) 78619.5 0.0 0.0 0 48528.2


248

surplus for tributes that supported a centralised political system and an archaic state evolving at

this time.

A number of arboreal, root and tuber species composed this archaeological production

system at Heketa. As was the case for Talasiu and Leka, these species represent a mix of both

primary crops and supplementary species. However, the number of species identified within

micro- and macrobotanical remains is much smaller compared to the two other sites, with only

seven primary crops and four supplementary species. This could suggest a preservation bias.

These taxa are primarily prehistoric introductions, aside from Cocos nucifera. Ipomoea batatas

is either a prehistoric or historic import to Tonga, but is treated as part of the primary crops

within the assemblage from Heketa due to the late prehistoric date ranges for these deposits.

This decision was made to at least attempt to model a system that includes I. batatas as this is a

dryland crop that currently grows well in Tonga, and if it was introduced earlier than expected,

would have played an important role in plant production and overall system efficiency. This will

be discussed in greater detail later in this chapter.

Table 9.10 Identified families and species within archaeobotanical remains from Heketa (TO-Nt-2)

Species diversity at Heketa is very low, with only 11 species in total, again possibly

indicating preservation bias. When the taxa are grouped into primary and supplementary

species, there is no significant nutritional diversity between these two groups. The averages of

these groups differ by 1.56 standard deviations, but based on the number of samples being

compared this figure equates to an 80% probability that these samples are different, which is not

high enough to reject the null hypothesis that these groups share similar nutritional values. The

average yield ratios indicate low-to-high diversity within these species (see Table 9.11), based

on the possible range provided by the example systems. Finally, a statistical comparison of

labour invested into the primary and supplementary species using Student’s t test, based on the

range of data from modern systems, indicates that there is insignificant labour diversity between

these groups (see Table 9.12 and Table 9.13). The highest probability of difference was seen

within the data from the Bellona system, which differed by 1.3 standard deviations and 70%

Family Species


Araceae

Alocasia macrorrhiza


Colocasia esculenta



Convolvulaceae Ipomoea batatas



Musaceae Musa spp.


249

confidence in mean difference, but again this was not enough to reject the null hypothesis. From

these criteria, the archaeological system represented by archaeobotanical data from Heketa can

be characterised as:

Heketa— low species diversity, insignificant nutritional diversity between groupings,

insignificant labour diversity between groupings, low-to-high yield ratio diversity.

It was expected that an archaeological plant production system dated to around 800-600

BP in Tonga would most closely resemble the Anutan system, based on current ideas upon the

links between intensive systems and the development of social hierarchy. The modelled

characterisation of the system at the Heketa site would suggest that this system probably was

more like that recorded on Ontong Java by Bayliss-Smith (1973, 1977). If this is true, then the

overall efficiency of the Heketa system in terms of outputs to inputs would be higher than if this

system had been more similar to Anuta. The result of this is a modelled overall nutritional

efficiency of 7846kcal/hr (Ontong Java), rather than 881kcal/hr (Anuta). This characterisation

suggests that the Heketa system could have been less labour intensive than originally thought. It

is also possible that increased trade networks during this time had enabled the economy to

incorporate the export of some higher yielding but lower labour investment crops in exchange

for the import of other subsistence items, as seen in the Ontong Java economy.

Table 9.11 Yield ratios for species identified at Heketa modelled using comparative example systems

Table 9.12 Labour inputs for species identified at Heketa modelled using comparative example systems


Alocasia macrorrhiza 0.0 5.5 0.0 6.3 0.0



Cocos nucifera 0.0 30.0 0.0 0.0 0.5




Ipomoea batatas 16.6 3.0 0.0 15.3 25.7

Musa sp.2 5.7 21.4 2.5 25.1 9.6


Spondias dulcis 0.0 83.3 0.0 0.0 0.0

Average 8.1 17.6 0.3 5.1 3.5

Grouping Species

Gadio Enga


Bellona Is

(hours/yr)

Anuta

(hrs/37 days)

Tongatapu

(hrs/yr)

Ontong Java

(hrs/yr)

Primary crops Alocasia macrorrhiza nd 11872.0 0.7 296824.2 183.0





Ipomoea batatas 30.1 33000.0 0.7 6394.5 183.0

Musa sp.2 30.1 9425.0 20.3 1404.4 183.0





Average 25.1 8809.6 30.9 36575.2 41621.7

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Table 9.13 Statistical comparison of labour inputs for groupings at Heketa in terms of mean difference

modelled using comparative systems

Comparison of expected and modelled outcomes

There are some significant discrepancies between the expected and modelled characterisations

of the archaeological production systems. Based on previous data and hypotheses, it was

expected that the late Lapita site of Talasiu would resemble the ‘broad-spectrum’ subsistence

system of the Gadio Enga, the Formative Period site at Leka would have been similar to the

mixed shifting cultivation of the Bellona system, and the late Formative and early Classic Tu’i

Tonga chiefdom site of Heketa would resemble the more intensive Anutan system. However,

modelling these archaeological systems based on the criteria for productivity and diversity used

to describe modern systems indicated similarities to different systems within this range. The

modelling exercise suggested that Talasiu could have instead resembled the Tongatapu 2001

system, while Leka was modelled to have been more labour intensive and less efficient than

previously assumed and so closer to the Anutan system. Interestingly, Heketa was suggested to

be closer in similarity to the production system of Ontong Java, which features land and labour

intensive subsistence and cash-cropping techniques with little investment in gathering of semi-

cultivated, naturalised or native species.

Unfortunately, there was no descriptive context provided in the Tongan Agricultural

Census (Ministry of Agriculture and Forestry 2001). Therefore, it may be useful to consider the

context of the Bellonan system, based on already established similarities between the

environmental context, shifting cultivation practices and productivity of these two systems. The

Bellona system was based on ‘manipulated and natural ecosystems’ (Christiansen 1975:29).

Gardening was conducted alongside gathering, collecting and fishing. The term ‘gardening’ was

used by Christiansen for these reasons: “...tilling is not practised, plants are individually placed

in individually treated sites, the areas planted are usually small, and generally the plants used in

these areas are annuals, vegetatively propagated (corms, tubers, bulbils, cuttings) and are thus

not sown, but laid/planted.” (Christiansen 1975:30) Local gardening was described as a

rejuvenation of a natural juvenile ecosystem after initial clearing, with high biomass production

and relatively low species diversity. Soil fertility was maintained through long fallow periods

enabling wild plant regeneration and nutrient cycling. This characterises shifting cultivation and

thus the Bellonan system is described as such by Christiansen (1975:31).



supplementary) 12.1 0.0 0.0 0% 0.0


supplementary) 10520.1 8589.6 1.3 70% 11136.7


supplementary) 15.2 16.2 0.7 50% 10.8


supplementary) 100536.9 71090.3 0.8 50% 53567.7


supplementary) 878.899.24 0.0 0.0 0 0.0


251

The exploitation of a number of niches in these manipulated and natural ecosystems

was enabled through the application of simple technology that involves low and ‘rational’ inputs

of labour to achieve subsistence sufficient only for local needs (1975:30). Christiansen ascribes

lower efficiency, but greater stability to the utilisation of natural potential on the island.

Analysis of output to input ratios within this study indicated that this was not always the case.

For example, Spondias dulcis or Otaheite apple, which is a semi-cultivated species, was shown

to have the highest nutritional return ratios of all of the species in the Bellonan system, due to

very low labour investment for a high yield. These differences in views on efficiency could be

due to the types of outputs measured, seasonal variation or the nature of data included in the

original study which also made use of fishing records.

The techniques described for cultivation through shifting cultivation, combined with the

exploitation of natural resources on this raised limestone island, makes sense when compared

with the Talasiu data. Although it was expected that the balance of labour invested in cultivated

to supplementary-type species exploited would be more similar to the Gadio Enga ‘mixed’

subsistence, by 2650 BP the island may have been settled for several hundred years. It is

possible that this later stage of island colonisation was already characterised by greater

emphasis on multi-cropping in vertically stratified gardens of crop storeys starting with

vegeculture interspersed with tree crops such as bananas and breadfruit (Addison 2006) using

shifting cultivation.

A more surprising outcome of modelling was the suggestion that the archaeological

production system represented by botanical remains extracted from Leka was most similar to

the Anutan system. The use and cultivation of plants on Anuta was described by Yen (1973b) as

“...one of the most intensive extant in the Pacific, despite the shortage of land and water, which

could have conferred the potentiality for the well-known forms of intensive agricultural

production, irrigation farming of taro.” Yen (1973b:139) clarifies that this system is a mixed

agricultural form of both high and low labour requirements which together indicates a highly

intensive system. Technologically, agriculture was seen as intensive due to the construction of

structures such as dry terraces or permanent fields, also in terms of land use within agronomy

through crop rotation, mulching, and finally labour expenditure. The intensity of this system

was such that Yen (1973b:148) also argues that the attainment of carrying capacity would span

a shorter period on Anuta than in many other island settings, and in fact the island was close to

this point when the original study was conducted. Forms of storage were utilised for many of

the root, tuber and tree crops that are high in starch content. This involved the fermentation of

processed taro, manioc, breadfruit, banana, Cyrtosperma taro, and Burckella fruits, and sealing

within lined pits for periods of time that are crop-specific. Yen describes storage as a possible

means of dealing with population increase, and indicates the emergence of more formalised

agricultural organisation in Anutan prehistory (1973b:147). Anuta was completely self-

252

sufficient at the time that this system was recorded, without any real cash objectives in

agriculture such as those seen elsewhere on the production and export of copra. This presented

Yen (1973b) with a unique opportunity to study traditional subsistence without any modern

industrial influences, and is one of only two systems analysed within this study that had no

cash-cropping.

Several key concepts within Yen’s description of the Anutan system offer possible

explanations for the similarities between this and the archaeological system at Leka. At first

glance, it is surprising that agriculture in Tonga may have intensified to the point of

comparatively low system efficiency in terms of nutritional returns already by 1300-1000 cal

BP. However, when this is considered in terms of the modelled carrying capacity of Tongatapu

in terms of agricultural acreage required to support an increasing population, argued to have

been reached as early as 800 BP (Kirch 1994) or 1000 BP (Green 1973), some contextual

similarities emerge. The described self-sufficiency of the Anutan system may have also

characterised agricultural production on Tongatapu during dates represented within deposits at

Leka, as the extensive networks of trade and interaction associated with the maritime chiefdom

were established at this time but later intensified (Clark et al. 2014). It is therefore possible that

Tongatapu had been nearing the attainment of carrying capacity at this time, and therefore

agricultural production was reducing in system nutritional efficiency during the Formative

Period.

This assumption ties into Kirch’s (1994) argument that the stimulus for warfare and

conquest was often the need to expand agricultural production in dryland systems such as that

seen on Tongatapu and in the Hawaiian archipelago. Expansion of political control acquired

greater land under one centralised polity, and relieved pressure on existing land currently under

production. The development of political economies, especially within primary and secondary

states, is therefore generally seen as directly related to the emergence of intensive and expansive

agricultural systems. Kirch (1994:27-244) drew on the ethnographic as well as archaeological

record of the two chiefdoms of Sigave and Alo-Alofi from Futuna, which indicated that

agricultural practices in wet and dry environments responded to identical underlying pressures

of population increase and of the societal demands for surplus to fuel the competitive

exchange/feasting cycle. Whereas Sigave (wet) could utilise opportunities for pondfield

irrigation of taro, the opposing chiefdom of Alo-Alofi (dry) was forced to adopt more labor-

intensive short-fallow shifting cultivation, closer to Boserup’s model of intensification

(1994:244). In an extension upon this model, McCoy and Graves (2012) suggest that the limited

potential for surplus production from small valley irrigated fields on the island of Hawaii could

place these systems in the same category as rain-fed dryland farming, influencing decisions to

engage in expansionist warfare by chiefs seeking to expand their power base. The Hawaiian

data is further supported by archaeological and ethnographic research conducted within the

253

Austral archipelago (Bollt 2012), where chronologies of inter- and intra-island warfare were

stimulated by the limited potential for irrigation of taro due to island size and environmental

constraints.

It is possible that greater investment of labour into primary crops may have reduced

overall system efficiency in the past, but energy storage through in-ground surplus accumulation

(Bayliss-Smith and Hviding 2014) may have instead increased the efficiency of particular taxa

in terms of social returns. These social returns would have both stimulated and been created by

the increasing socio-political complexity of the Tongan cultural system. Elites mobilised

subsistence goods from commoners by asserting ownership over agricultural land, thus enabling

the supply of food to specialists such as warriors and priests who validate the authority of those

elites. This Formative Period has been pinpointed as a critical stage in Tongan prehistory that

likely lead to the development of the classic Tu’i Tonga chiefdom after 1000 BP, or possibly

later. The modelled changes in agricultural production and associated environmental constraints

described here could go some way towards explaining why these socio-political developments

occurred later.

This hypothesis is further supported by the modelled similarities between the Ontong

Java and the archaeological plant production system at Heketa from 800-600 cal BP. It was

expected that this archaeological system would most likely resemble the Anutan system due to

increasing system intensity over time as a result of the need for surplus production facilitating

socio-political developments. However, modelling suggested that in fact the earlier system at

Leka was more similar to the Anutan system, and that Heketa most likely resembled the slightly

more nutritionally efficient Ontong Java system. Considering this and earlier discussion upon

the limits of carrying capacity on Tongatapu, it is possible that by 800-600 cal BP

archaeological production had increased in efficiency through the introduction of export items

from trade within the increasing network of islands under the control or influence of the

maritime chiefdom. Primary crops that were more nutritionally efficient in terms of labour

investment could have been incorporated into the diet on Tongatapu, not necessarily through

production but through importation and redistribution. This was documented ethnographically

as part of the festival and tribute system, where yam production in particular was monitored by

chiefly-appointed petty officers and brought to Tongatapu from as far afield as Vavau as part of

the first fruits or ‘inasi festival (Cook in Beaglehole 1969; Gifford 1929; Mariner in Martin

1991). A crop of yams was planted around one month before the regular crop, and was

harvested early in time to be given as tribute for the festival (Mariner in Martin 1991). Other

festivals were also conducted throughout the year to ensure the productive success of

cultivation, with gifts of yams, coconuts, kava root, fish and arrowroot given to the gods, the

chiefs and their households (Mariner in Martin 1991).

254

If this hypothesis is accepted, there are three explanations as to why the system at

Heketa may have been similar to the Ontong Java production system, and appears to have

increased in overall nutritional efficiency since the Formative Period. The first possibility is that

the low preservation of microbotanical remains at Heketa led to the exclusion of some species

from the system modelling exercise. The second option is that the incorporation of tributes from

other islands, as well as traded goods, allowed renewed investment of labour into more

nutritionally efficient but lower yielding species. Tied to this is a third explanation— that the

archaeobotanical record at Heketa may not in fact reflect only those species that were produced

or utilised from Tongatapu, but also these other islands and so appear greater in overall

nutritional efficiency. Each of these will be explored here to further understand and explain the

modelling of this archaeological system.

The comparatively low quantities of starch and also the number of species present

within the archaeobotanical remains at Heketa suggest that the microbotanical preservation at

this site was not good. Most surprising was the absence of any starch identified as belonging to

the Dioscorea or yam family. Clearly these were heavily relied upon at the point of European

contact, and evidence from Talasiu and Leka indicate that these crops had been cultivated in the

past. This suggests that there are certainly some species missing from the production system at

Heketa. As yams are not as nutritionally efficient as many other staple crops such as bananas

(Musa spp.) or sweet potato (Ipomoea batatas), but are generally more efficient than the aroids,

it is possible that the actual production system at Heketa may have been less efficient than that

from Ontong Java. Interestingly, yams were not cultivated within the Ontong Java system,

which instead focussed primarily on the subsistence production of aroids such as Colocasia

esculenta and Cyrtosperma merkusii, sweet potato (Ipomoea batatas) and the cash-cropping of

Cocos nucifera. This omission may have biased the model towards characterising the Heketa

system as most similar to that from Ontong Java but also may point to the increasingly

important role of sweet potato in the Tongan economy.

Overall the two key differences between the Anutan and the Ontong Java system are

that there is more labour invested in supplementary species and greater diversity within yield

ratio in the latter example system. As has been demonstrated within this study, the investment of

some labour into non- or semi-cultivated species often results in high nutritional returns due to

high nutritional rankings, especially arboreal species. By specialising in the cultivation of

primary crops such as yams and aroids which have moderate yield ratios but low overall

nutrition, the Anutan's decrease the overall nutritional efficiency of the system. The type of

‘technoenvironmental efficiency’ which has been measured within this study applies

specifically to the Ontong Javan, Bellonan and Tongan ethnographic systems due to the

inclusion of de facto outputs. These are the surplus outputs or yields that are created to facilitate

the exportation of goods for cash-cropping, but do not include the cash or traded goods that

255

come back into the system. It is therefore possible to measure the role that the creation of

surplus would have played, but difficult to accurately assess how the incorporation of any

tributes that fed back into the system would have benefitted the efficiency of the production

system at Heketa.

It seems likely that the introduction of alternative sources of nutrition without any

primary labour inputs would have increased overall efficiency, but this cannot be modelled here

without knowing the exact labour investment data. In any case, it is unlikely that goods were

only moving in one direction— into Tongatapu—after the Fiji-Western Polynesian interaction

sphere was established. The incorporation of tributes into diet and the economy on Tongatapu

may have enabled the renewed investment of labour into more nutritionally efficient

supplementary species and therefore may explain the increase in system efficiency after the

Formative Period (Leka). We cannot know for sure whether species present at Heketa were

grown nearby but, as explored here, this may explain the similarities to Ontong Java along with

the changes in decision-making in production resulting from the tribute system.

Specialisation and system efficiency

Patterning between modelled system efficiency and ratios of numbers of primary to

supplementary systems indicates a link between these two variables. Modelled system

nutritional efficiency was based on figures derived from the characterisation of past systems and

similarities to modern production systems (see Figure 8.36). Talasiu most closely resembled the

system on Tongatapu in 2001, while Leka resembled Anuta and Heketa probably resembled the

Ontong Java system (see Table 9.14). The modelled efficiency of these systems therefore

decreases between Talasiu (2750–2650 cal BP) and Leka (1300-1000 cal BP), before increasing

slightly again at Heketa (800-600 cal BP). The numbers of primary and supplementary species

within these systems vary over time. The highest ratio of primary to supplementary species was

observed at Leka (2:1), while the lowest was at Talasiu (1.3:1). Considering this, a link can be

drawn between specialisation in primary crops, seen through this high ratio at Leka, and

decreased system nutritional efficiency. Similarly, diversification through exploitation of a

number of supplementary taxa alongside primary crops, can be linked to increased system

efficiency at Talasiu, with Heketa falling somewhere between these two systems.

Table 9.14 Comparison of modelled system efficiency with ratios of primary to supplementary species

Archaeological

system

Ratio of primary to

supplementary species

Modelled system Nutritional efficiency

(kcal/hr)

Talasiu (2750-2650 cal BP) 1.3:1 Tongatapu 123996

Leka (1300-1000 cal BP) 2:1 Anuta 1268

Heketa (800-600 cal BP) 1.4:1 Ontong Java 7846

256

Contamination at Leka and Heketa

The issue of contamination from white potato (Solanum tuberosum) and also possibly sweet

potato within archaeological deposits at Leka and Heketa needs to be addressed. Contamination

is most likely to have occurred during field collection, or laboratory processing for starch

extraction. Modern starch contamination during collection and handling of samples in the field

has been discussed within a number of studies. These have indicated that modern starch can

enter archaeological soil samples during sampling from aeolian (wind) sources (Laurence

(2013; Laurence et al. 2011; Loy and Barton 2006; Messner 2011), although this is unlikely in

Tonga as starch tends to only becomes airborne when dried, or from handling of samples

(Barton et al. 1998:1233; Hart 2011) Through experimentation with laboratory processing and

also assessment of current literature, it was discovered that some laboratory grade chemicals and

equipment contained modern native starch. Previous studies had recorded high numbers of

starch from wheat (Triticum sp.), white potato (Solanum tuberosum), and maize (Zea mays) on

powder-free gloves, pipette tips, paper towels, and within Calgon and Sodium polytungstate

commonly used for heavy liquid separation (Campbell et al. 1984; Crowther et al. 2014;

Laurence 2013; Laurence et al. 2011; Makela et al. 1997; Newsom and Shaw 1997; Wilson and

Garach 1981). This was confirmed by testing lab materials used in this study, with Calgon

providing the greatest source of contamination. Airborne starch was also found in laboratory

spaces in low numbers in native and modified condition (Crowther et al. 2014; Laurence et al.

2011; Newsom and Shaw 1997).

Appropriate protocols to limit starch contamination have been suggested by previous

studies, and were built on here. These involved using starch-free gloves and zip lock bags both

in the field and in the laboratory, cleaning the face of the baulk before sampling in the field,

cleaning sampling equipment or using individual sampling equipment for each stratigraphic

unit, sterilising all laboratory equipment and workspaces, and filtering 5% Calgon solutions to

remove any modern starch before use. Unfortunately, these techniques can only limit

contamination and it is always possible that some modern starch has entered archaeological

samples. However, the common types of contaminants, namely wheat, maize and white potato,

would be easily identified within samples from Tongatapu as these are unlikely to have been

grown at any time on the island. The presence of the white potato or Solanum tuberosum at

Leka is most likely explained as a contaminant from pre- or post-excavation handling or

processing.

The historical integrity of samples is therefore presumed to be intact and all other

species present are assumed to be of prehistoric age. This is supported by the co-occurrence of

parenchyma at Talasiu identified as C. esculenta, A. altilis fruit, D. alata, D. nummularia, Musa

spp., and Zingiber spp. It is also assumed here that the presence of sweet potato at Heketa is not

a modern contaminant as the dating of other archaeobotanical remains of this species within

257

deposits from Eastern and Central Polynesia coincide with the later deposits from TP4. There

are also numerous instances of early historic and ethnographic documentation of extensive

sweet potato cultivation on Tongatapu. This evidence will be discussed in detail within the next

section of this chapter, dealing with the timing of crop introductions into Tonga.

Linking archaeobotanical data to island colonisation and

social complexity

The archaeobotanical identifications from Talasiu (TO-Mu-2), Leka (J17), and Heketa (TO-Nt-

2) were discussed in this section, in terms of agricultural production systems at various points in

Tongan prehistory, and the broader context of these species-level identifications. Modelling

archaeological production systems based on characteristics defined for modern systems in the

west Pacific, such as species diversity and nutritional efficiency in terms of outputs to labour

inputs, enabled a basic analysis of crop production in the past. Some variables were unknown

and so the full possible range for each species, based on the figures from modern systems, was

assumed in each archaeological system in terms of yield and labour inputs. Species in each

system were defined as primary crops or supplementary based on ethnographic and agricultural

studies from Tonga, in order to assess the statistical differences between these two groups in

terms of yield, nutritional efficiency and labour inputs.

Comparison of modern systems revealed that overall system efficiency was often tied to

the inclusion of a number of supplementary species within subsistence systems, rather than a

heavy reliance on primary crops. Specialisation in primary crops can therefore be linked to

decreased overall system nutritional efficiency. Supplementary species, especially arboreal,

tended to have higher nutritional value than most primary crops, but had lower yield ratios in

terms of productivity from labour investment. Some balance between the two groups resulted in

higher system nutritional efficiency, such as that seen in the Bellona system in the Solomon

Islands (Christiansen 1975). Less efficient systems such as that observed by Yen (1973b) on

Anuta invested more labour into a narrow range of primary crops, resulting in lower ratios of

nutritional returns to labour inputs than that recorded in other systems. This trend was

reinforced through the links between ratios of primary to supplementary species, and modelled

system efficiency within the archaeological systems. This patterning was critical towards

linking decreased system efficiency to the formation of centralised government on Tongatapu.

The results of this study suggest that plant production strategies after initial settlement

on Tongatapu by the eastern Lapita Cultural Complex, under a decentralised social hierarchy,

may have involved a greater diversity of species than originally presumed. Many of the core

traditional cultigens were present within archaeological deposits at Talasiu from 2750-2650 cal

BP, including a number of root crops from the aroids (Araceae), and yams (Dioscorea spp), as

well as arboreal crops such as bananas (Musaceae) and breadfruit (Artocarpus altilis).

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Alongside these were a number of supplementary crops such as kava (Piper methysticum),

ginger (Zingiberaceae), and arboreal fruits including the Otaheite apple (Spondias dulcis) and

the Tahitian chestnut (Inocarpus fagifer). This range of both primary and supplementary species

most likely resulted in a relatively efficient system in terms of nutritional returns through

diversification of labour investment, and would have been utilised alongside hunting and

gathering of marine resources. The hydro-isostatic drawdown affecting sea levels within the

Fanga’Uta Lagoon during the mid-Holocene (Dickinson 2001, 2007) appear to have gradually

impacted this harvesting of marine species in terms of lower species diversity and size (Grono

2012). Overall subsistence strategies at this time appear to have turned towards the exploitation

of terrestrial resources in the archaeobotanical record at Leka from 1300-1000 cal BP. The

number of species present within test units at this site increase slightly from that observed at

Talasiu to include a number of highly ranked crops such as Dioscorea esculenta and Curcuma

longa in terms of nutritional value but low in terms of yield to labour investment. These species

served to increase the diversity of labour investment between primary and supplementary

species (suggesting specialisation), and decrease the overall efficiency of the system. Finally, a

much smaller list of species was recovered from archaeological deposits under the Heketa (TO-

Nt-2) in the north east of Tongatapu. This is thought to be due in part to taphonomic factors

affecting microbotanical preservation, but also could reflect subsistence changes resulting from

the development of social hierarchy in Tongan. Overall, modelled system efficiency increased

slightly from that seen at Leka, owing to less labour diversity within primary and supplementary

crops (diversification) and higher overall yield to labour input ratios. It has been suggested that

the networks established through the maritime chiefdom would have increased trade and tributes

coming into Tongatapu, alleviating pressure on subsistence when carrying capacity was

approached.

These plant production systems were clearly engaged in a cyclical system of

involvement with the evolution of social hierarchy and associated socio-political development

in Tonga over time. They both facilitated and encouraged change through cultural reactions to

decreasing system nutritional efficiency, and were impacted by these changes through the

introduction of new species or changing species diversity (diversification vs. specialisation).

The assessment of individual species introductions into Tonga further expands the context of

these changes. Most species were introduced into Tonga within the first few hundred years of

settlement, relied on as supplementary or primary cultigens that complemented the exploitation

of marine resources. Demographic and environmental factors such as soil geology and climatic

limitations are thought to have pushed Tongatapu to reach carrying capacity by as early as 1000

BP, necessitating expansion of political control to alleviate pressure on local subsistence

systems. Clearly, there is an overall decrease in system nutritional efficiency and increase in

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social complexity after 2750-2650 cal BP, linked to increased specialisation in the production of

primary crops over supplementary crops (see Figure 9.1).

Figure 9.1 Trend towards decreased system nutritional efficiency and increased social complexity after Lapita

occupation at Talasiu (2750-2650 cal BP)

Modelling archaeological production systems and the introduction and utilisation of

individual species into Tongatapu was carefully assessed with relation to current debates and

evidence from both Tonga and the wider Pacific. Attempts were made to model how and why

plant production systems were utilised on Tongatapu, using high resolution techniques to extract

archaeobotanical data from three well-dated sites. The data from Talasiu (TO-Mu-2), Leka (J17)

and Heketa (TO-Nt-2) was interpreted within a Human Ecological framework to model

agricultural systems, and sought to validate or provide alternatives to current hypotheses and

expectations. The implementation of further archaeobotanical research will either support or

disprove the narrative for the development of agricultural systems in Tongan prehistory

presented here, but at least a new baseline has been provided against which new data can be

applied.

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Chapter 10 Conclusion

Meeting research aims and objectives

This thesis had two main objectives. The first of these was to construct a comprehensive

comparative collection of both starch grains and vegetative storage parenchyma from economic

and supplementary plant species in Tonga. A detailed morphological study was carried out on

these micro- and macrobotanical remains to discern how taxa could be differentiated.

Morphological analysis also enabled the development of tools (multivariate statistics and

identification flowchart keys) to identify samples of unknown origin to taxonomic levels. The

second objective of this research was to utilise the comparative collection to identify

archaeobotanical remains from three sites on Tongatapu dated from 2750-2650 cal BP (Talasiu),

1300-1000 cal BP (Leka), and 800-600 cal BP (Heketa). Cultural deposits at these sites contain

archaeological data from three time periods within Tongan prehistory, ranging from late Lapita

through to the early stages of state formation in Tonga.

Several key research questions were asked of the archaeobotanical data from Talasiu

(TO-Mu-2), and deposits underneath Langi leka (J17) and Heketa (TO-Nt-2). One primary

question examined was whether early colonisers in West Polynesia were dependent on

introduced crops, or if human dispersal was fuelled predominantly by the exploitation of natural

resources. A further research question sought to establish whether archaeobotanical data can

provide new evidence to examine the role of agriculture within the development of the maritime

chiefdom in Tonga. After conducting this archaeobotanical research, several important

conclusions were drawn about the comparative collection and the role of plants in Tongan

prehistory. These are summarised here and will be explored in further detail within this chapter:

Multivariate statistical analysis and identification flowcharts can enable the

discrimination of starch and vegetative storage parenchyma from most Tongan

economic and supplementary taxa based on metric and nominal morphological

attributes.

A detailed chronology of plant introductions from three sites on Tongatapu indicate that

most staple cultigens and some supplementary or famine foods were brought to Tonga

within a few hundred years or less of initial Lapita colonisation. Late prehistoric

introductions likely included the sweet potato (Ipomoea batatas) by 600 BP, transported

from South America via East Polynesia through the extensive trade networks of the

developing Tongan state.

Production systems involving the cultivation of these core cultigens alongside a number

of semi-cultivated taxa, changed over time in terms of species diversity through

diversification of labour or specialisation in primary crops, and overall system

efficiency based on modelled nutritional value, yields and labour investment. Modelled

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production systems here links decreased system efficiency to increased horticultural

specialisation. This trend can be linked to a contemporary increase in social complexity

through development of centralised government and control of resources that enabled a

slight increase of system nutritional efficiency by 800-600 cal BP through minor

diversification (either through production on Tongatapu or de-facto outputs). This

supports the view that expansion of Tongan control within Fiji-West Polynesia was

likely stimulated by extensive dryland agricultural production on Tongatapu, population

increase and environmental limitations to production.

One of the primary aims of this thesis research was to develop a comprehensive

reference collection of starch and vegetative storage parenchyma from economic plants in

Tonga. This was a crucial step towards identifying archaeobotanical remains from the three sites

of Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2) on Tongatapu. Around 40 plant

species were collected during surveys of plantations in Tonga, Fiji and Palau. Of these, 35

species were able to be sampled and analysed for parenchyma, and 27 contained significant

quantities of starch to enable statistical sampling of granule morphology. A number of species

had several organs sampled, as more than one organ could be consumed or otherwise utilised

according to ethnographic and ethnobotanical records of plant use. To enable accurate

identification of these micro- and macrobotanical remains, detailed morphological studies were

carried out that assessed a range of both metric and nominal attributes. The use of high

resolution imagery with Scanning Electron Microscopy (SEM) enabled greater accuracy of

measurement and more detailed description of morphological variables than with standard light

microscopy. Morphological studies facilitated differentiation of the species within the reference

collection through characterisation of the full range of morphological variation in each sample.

There was considerable overlap within the distribution of many of these attributes within both

starch and parenchyma in the reference collection, but multivariate statistical comparison of

metric variables highlighted attributes where these species varied.

Both starch granules and vegetative storage parenchyma form and compose the

structure of plant organs that are most commonly consumed within the traditional subsistence

strategies of the Pacific region and represent crucial direct evidence for the cultivation and

dietary contribution of Pacific cultigens. It is essential that the morphological characteristics of

each species is imaged and described accurately to identify these micro and macrobotanical

remains. A combination of light microscopy and SEM were used to image and measure the

variables described here, and this data was assessed using a combination of identification

flowcharts and multivariate statistics in the form of Discriminant Function Analysis (DFA). All

summed data and imagery was entered into a Filemaker database that will be made available

online for public access.

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Identification flowcharts are more basic forms of morphological descriptions and were

used to distinguish the range of characteristics present within each species or plant organ

sampled in the reference collection for parenchyma. Due to the range of characteristics within

different tissue types in the samples of parenchyma, it was decided that multivariate statistical

analysis of the full range of attributes for each species would not be useful. Tables were created

in this study for both starch and parenchyma that summarised a number of key characteristics

and will facilitate the identification of unknown archaeological material. From this, two

flowcharts were used (with vascular tissues and without) that broke down these attributes of

parenchyma within the reference collection. These incorporated both fresh and charred

morphological characteristics of the various boundary, ground and vascular tissues. Sometimes

it was not possible to distinguish samples beyond family or genus level due to very similar

characteristics or a large amount of overlap. Overall, these identification flowchart keys allowed

a number of key taxa to be identified with moderate confidence and prefixed with ‘C.f’, as

samples both resembled images and matched geographic range of species.

Multivariate statistics enabled a full comparison of all metric and nominal variables

within starch granule morphology, and was also utilised to discriminate between the

distributions of individual attributes of parenchyma within species in the reference collection.

Nominal (discontinuous) variables were converted into binary (presence or absence) variables to

facilitate the comparison of these non-metric attributes. A comparison of the full range of

morphological variables in starch granules was conducted by dividing the main dataset into two

smaller datasets, according to the angle at which granules were viewed and recorded. This

created an eccentric (side-on) and a centric (end-on) dataset. Confusion matrices were created

that indicated how well each species or plant organ could be distinguished from all other species

included within each dataset. These showed the distribution of classifications when linear

discrimination is used to assess morphological variance for each species, in essence these

highlight the percentage of starch granules that were correctly re-assigned to the species of

origin based on the characteristics recorded. Higher percentages of correct re-assignments

indicated that a species or organ contains starch that is less similar to other species and can

therefore be more easily distinguished morphologically from others within the dataset. These

matrices also indicated the species that morphologically overlap and therefore tended be

misclassified as one another. The overall results of this analysis produced 67.61% correct re-

assignments within the eccentric (side-on) view and 46.78% within the centric (end-on) view.

This technique has both strengths and weaknesses, resulting from inherent statistical

assumptions. A number of parameters have an effect on the accuracy rate of DFA classification,

including the number of groups, the number of predictor variables, and sample sizes in each

group. A primary weakness of the automated classifications generated by DFA is that this

technique must provide a group assignment. These assignments are therefore exclusive and so

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restrict identification of unknown samples only to those groups or species included in the

analysis. If archaeological (unknown) starch derives from taxa that are not in the comparative

collection, DFA will still attempt to classify granules to taxa or groups that are included.

However, a review of the scores of the first two canonical variates for each unknown granule

can indicate how close the match is to the range for reference species. DFA is also designed to

maximise the differences between groups. This results in an overall tendency to correctly assign

individual granules at a higher rate than that expected by chance alone, even if the dataset is

comprised of predictor variables (attributes) that in fact bear no real relationship to group

membership. Unless each of the outputs for predictor variables are assessed (in this case

attributes) the results of DFA can be mistakenly interpreted as representing the successful

attribution of individuals to their groups on the basis of meaningful functions, when instead

these are the result of the inherent property of the analysis. With this in mind, it is important that

the discriminatory values of attributes are assessed before the classification of unknown

granules is attempted. This check provides an indication of the probability of failing to

distinguish between two plant taxa. Another benefit of this step is that this provides an

assessment of all morphological variables and identifies which are most important for

discrimination between taxa, and classification. Overall, multivariate statistical analysis created

a useful automated classification system for archaeological starch that could be interpreted with

low-to-high confidence, and confirmed using visual checking of images from both light

microscopy and SEM. Observer bias is not removed from this process but further highlights the

importance of using a population rather than a single case approach to identification. Not all

granule morphologies are characteristic and the presence or absence of a nondiagnostic form in

association with a more generic type could be definitive of a particular species (Torrence et al.

2004), a relationship that only multivariate statistical analysis considers.

This archaeobotanical study is the first to combine two detailed complementary records

of micro- and macrobotanical remains from the same organs of economic plant species in the

Pacific region. A stringent sampling strategy and consistent recording techniques, particularly in

the case of starch, enabled the accurate recording of a number of variables deemed useful within

current literature (Crowther 2009; Hather 1991, 1994, 2000; ICSN 2011; Torrence, Wright and

Conway 2004; Wilson et al. 2010). This process resulted in the identification of many

diagnostic attributes at various taxonomic levels. Further, the incorporation of multivariate

statistical analysis highlighted the amount of morphological overlap between these species, and

pinpointed those species that could be identified with greater confidence than others within the

reference collection. It is intended that one major output of this research will be to make the

recorded data and images from both light microscopy and SEM available online, using the

Filemaker database that was created during this first component of this PhD project. There are

no online databases currently available for the Pacific region, and so this will be a major step

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towards encouraging more accurate and consistent identifications for preserved starch and

parenchymatous material found in palaeoecological and archaeological deposits.

Prior to this thesis research, little was known about the antiquity of crop introductions

into Tonga and their use in plant production systems in the past. A small number of

palaeoenvironmental studies (Fall 2005, 2010; Fall and Drezner 2011, 2013; Flenley et al. 1999)

have painted a picture of vegetation change from pollen and spores within swamp cores, and

also explored the timing and mechanisms for plant dispersal. The impact of human arrival in

Vava’u, Tonga was demonstrated through an increase in micro-charcoal after 2600 BP

suggesting the burning of tropical hardwood, and possible increases in soil erosion from

increased clay deposition between 2400 and 800 14C yr BP (Fall 2005, 2010). Lowered

numbers of native birds and bats (Steadman 2002) also probably led to the loss of rainforest

trees through disrupting seed dispersal mechanisms The introduction of a number of species

after 2600 BP, or an increase in pollen concentrations, is thought to be associated with Lapita

arrival and later Polynesian occupation (2010). New species introductions around 2600-2500 BP

included Casuarina equisetifolia, Colocasia esculenta, Cordyline fruticosa, Ludwigia octovalis,

Poaceae spp., and Pometia pinnata (Fall 2005; Flenley et al. 1999). Those species for which

pollen increased after this time, suggesting cultivation or expansion of habitat, included

Canarium harveyi, Cocos nucifera, and Pandanus tectorius (Fall 2005; Flenley et al. 1999). The

first appearance of a number of other species was documented within these studies from 2400-

1100 BP, including Erythrina variegata, Gardenia tannaensis and Stenochlaena palustris (Fall

2005; Flenley et al. 1999).

It is clear that there was a significant gap in terms of data regarding most species that

featured within ethnographic recordings of the traditional Tongan economy. Research as part of

this project sought to fill this gap through the application of high-resolution archaeobotanical

techniques upon well-dated archaeological deposits from throughout Tongan prehistory.

Through these methods, a chronology for the introduction and cultivation of many new plant

species was developed and can now be added to the existing data. From the site of Talasiu (TO-

Mu-2), dated to around 2750-2650 cal BP and therefore associated with late Lapita occupation

on Tongatapu, the first recorded evidence for a number of new economic species was

documented. These species included the root and tuber crops Amorphophallus paeoniifolius

(elephant foot yam or stink lily), Cyrtosperma merkusii (giant swamp taro), Dioscorea alata

(common yam), Dioscorea bulbifera (bitter yam), Dioscorea nummularia (spiny yam), Piper

methysticum (kava), and several members of the Zingiberaceae family (gingers). Introduced

alongside these were a number of arboreal or tree crops including Artocarpus altilis (breadfruit),

Inocarpus fagifer (Tahitian chestnut), Musa spp. (banana and plantains), and Spondias dulcis

(Otaheite apple). The presence of starch and charred endocarp of both Cocos nucifera (coconut)

and Barringtonia asiatica (fish-poison tree) within these deposits indicate that these species

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were utilised by those populations occupying Talasiu. Only two new species were recorded

from deposits at Leka (J17) dated to 1300-1000 cal BP. These included another species of yam,

Dioscorea esculenta (lesser yam), and another ginger, Curcuma longa (turmeric). Finally, the

introduction of Ipomoea batatas (sweet potato) and Alocasia macrorrhiza (giant taro) can be

documented from identified starch granules within deposits dated to 800-600 cal BP under the

Heketa (TO-Nt-2).

To understand the development of production systems that featured the cultivation and

consumption of these species, and how these linked to social complexity, a Human Ecological

approach to modelling archaeological systems was taken. A simple cost-benefit assessment of

system efficiency was carried out in terms of work inputs to yield and nutritional outputs, as

properties of systems within agricultural ecology (agroecology). Characterisation of these

systems were according to criteria roughly based on those suggested by Dornstreich (1977) and

included species diversity (number of species utilised), nutritional diversity between groupings

(e.g. primary or supplementary species), labour investment diversity between groupings, and

yield ratio diversity between all species. System ‘completeness’ was assessed through

nutritional comparisons with traditional economic species that were ethnographically recorded

at the time of European contact. It was concluded that there was no statistical differences in

terms of nutrition between those recorded ethnographically and archaeobotanically, even when

these were narrowed to those that produce starch or need to be processed or cooked before

consumption, and therefore more likely to be included in midden deposits. The only exception

to this is possibly Heketa, where starch quantities were very low compared to the other two

sites, and the absence of any yam species at this later stage in Tongan prehistory could suggest

that preservation of micro-remains at this site was not good and therefore the record is biased in

some way.

These archaeological systems were compared to a small number of published

ethnographic examples of systems from locations in the Western Pacific. These included that of

the Gadio Enga in the Highlands of Papua New Guinea (Dornstreich 1977), three Solomon

outliers including Bellona Island (Christiansen 1975), Ontong Java (Bayliss-Smith 1973, 1977,

1986) and Anuta (Yen 1973b), and Tongatapu (Ministry of Agriculture and Forestry 2001).This

exercise suggested that the late-Lapita production system at Talasiu (2750-2650 cal BP) most

closely resembled that recorded in the 2001 Tongan Agricultural Census, and therefore had an

overall modelled system efficiency of around 124kcal/hr. Plant production during the Formative

Period, as represented by identified species at Leka (1300-1000 cal BP) most closely resembled

the Anutan production system, and as such had a much lower modelled overall efficiency of

1.3kcal/hr. Finally production at the site of Heketa (800-600 cal BP) during the late

Formative/early Classic Tu’i Tonga Chiefdom period could have most closely resembled the

Ontong Javan system with an overall system efficiency of 7.8kcal/hr. This indicated that

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productive and nutritional efficiency decreased between Talasiu and Leka, but increased again

between Leka and Heketa, and emphasised the need to assess these systems in historical

context.

It is argued here that Lapita colonising populations on Tongatapu likely invested in the

production of a more diverse range of traditional core cultigens and supplementary species than

originally presumed. The nutritional value of these species and the implied nature of their

cultivation using a system of aroid pits (Cyrtosperma) and dryland multi-cropping techniques

with elements of arboriculture would have resulted in a relatively efficient system that was used

alongside marine-based and terrestrial foraging. Data from Leka suggest that plant utilisation

during the Formative Period reflected an increased interest in the exploitation of terrestrial

resources. This was due to marine resource over-exploitation and changes in the marine

ecosystem within the Fanga’Uta Lagoon resulting from hydro-isostatic drawdown of sea level

after the mid-Holocene marine high-stand. Specialisation in primary crops within the production

system at this time subsequently increased diversity within labour investment in primary and

supplementary crops and decreased overall system efficiency due to the limited nutritional

efficiency of new species. Soon after, Tongatapu may have been close to reaching carrying

capacity based on modelled population figures and acreages of cultivated land required to feed

them (Green 1973; Kirch 1984, 1988). One reaction to this situation would have been the

beginning of expansionist strategies that enabled the eventual development of the classic Tu’i

Tonga maritime chiefdom or state. The trade networks and control of agricultural resources

established by the central polity on Tongatapu after around 750 BP (Clark et al. 2014) created

an interaction sphere that may have served to relieve pressure on local production. This could

explain the modelled increase in overall system efficiency in the system at Heketa from 800-600

cal BP, owing to less labour diversity within primary and supplementary crops through minor

diversification into nutritionally efficient supplementary taxa, and higher overall yield to labour

input ratios.

A simple unilinear trajectory towards increasing labour inputs into dryland techniques

through fallow reduction and expansion of production, and decreasing overall system efficiency,

is not supported by the modelled data from this study. Instead evidence points towards a system

of causation and reaction to social, environmental and economic factors that enabled

populations to not only survive but also thrive on a raised limestone island such as Tongatapu

where a variety of ecological niches for diverse wetland cultivation techniques, such as those

observed on high islands, did not exist. The socio-political climate on the island evolved to cope

with environmental and climatic limitations on production, through expansion of control and

influence.

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Palaeonvironmental and ethnobotanical studies point to the almost complete removal of

primary forest on Tongatapu, replaced with plantations in various states of cultivation or bush

fallow, or areas of now permanent secondary forest (Ellison 1989; Fall 2005, 2010; Fall and

Drezner 2011, 2013. The geology and rich volcanic soils of the island lent themselves to the

gradual transformation of the landscape to full scale extensive multi-cropping and shifting

dryland production. This process inevitably led to demographic pressure on production, and

island carrying capacity being reached earlier than on many other Pacific islands (e.g. Vanuatu,

Fiji and New Caledonia). The system could not be further intensified in terms of further fallow

reduction or increased cultivation, and so expansion of political control to other islands in the

archipelago and the greater Western Pacific region would have been necessary. New interaction

spheres and control of resources could have enabled a change in the focus of vegeculture away

from some less efficient primary crops towards new species such as Ipomoea batatas (sweet

potato) (Allen and Ballard 2001; Ballard 2005; Green 2005; Leach 2005). All producers

participated in ethnographically recorded tribute systems (Cook in Beaglehole 1969; Gifford

1929; Mariner in Martin 1991) which created alternative systems of food redistribution. This

would have almost certainly nutritionally as well as socially benefitted most elements of society,

from the chiefs to the matapules and commoners in different ways. Ultimately, the adaptation of

production systems within an evolving social and political climate was a continuing process that

did not halt after European contact. The continued ability of those on Tongatapu to adopt new

crops such as Xanthosoma sagittifolium (tannia or talo futuna) and increase production of

traditional cultigens for export outside Tonga is evidence of a resilient relationship between the

people and the land.

Future recommendations

Micro- and macrobotanical techniques

A number of techniques were utilised in this study that are currently relatively underemployed

in the Pacific. Very few archaeological studies incorporate any archaeobotanical techniques

within research strategies, and those that do have tended to be without any strict sampling

regimes to ensure consistency and enable replication. Within those studies that have been

conducted, there have been numerous studies involving the identification and quantification of

pollen, phytoliths and wood charcoal due to high rates of preservation, while very few have

targeted starch and even fewer have analysed charred, water-logged or desiccated vegetative

storage parenchyma. Background research as part of this study has shown that this bias has been

the result of an unfounded belief that these remains do not preserve in tropical climates, and that

these remains cannot be confidently identified.

Starch is often analysed only as chance finds as residues on artefacts or soil samples

from archaeological features, and parenchyma has similarly been primarily collected as random

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finds that were often identified based on surface morphology rather than internal cellular

structure. These chance finds in the broader Pacific region, and preservation of starch and

parenchyma within deposits at Talasiu (TO-Mu-2), Leka (J17) and Heketa (TO-Nt-2), validate

the need to incorporate flotation or sieving within excavation techniques in projects that are

assessing subsistence and lifeways of people in the past. At the very least, bulk soil samples

should be collected to process and analyse later in a laboratory environment where less

contamination can occur. This study has demonstrated that these micro- and macrobotanical

remains can be extracted from a variety of archaeological deposits, and that these often preserve

relatively well in order to facilitate identification using techniques established here. Some

consideration does need to be given to sources of contamination within the field and laboratory

environment, and taphonomic processes, to ensure the antiquity of identified specimens.

It was foreseen that the development of a comprehensive reference collection would be

the best way to understand morphological variation at various taxonomic levels in starch and

charred parenchyma, and thus to identify archaeobotanical remains. The analysis of the

reference collection built upon the previous work of others (Allen and Ussher 2013; Babot

2001; Barton 2005; Barton et al. 1993,1998; Crowther 2009; Field 2006; Fullagar 2006;

Fullagar et al. 1996, 1998; Hather 1991, 1994, 2000; Horrocks 2004;; Horrocks and Barber

2005; Horrocks and Bedford 2010; Horrocks and Rechtman 2009; Horrocks and Weisler 2006;

Horrocks et al. 2004, 2012; Lentfer 2009; Loy 1994; Loy et al. 1992; Torrence, Wright and

Conway 2004; Ussher 2009) with regard to starch and parenchyma within the Pacific. The

analysis of a range of metric and descriptive nominal variables using light microscopy,

Scanning Electron Microscopy (SEM), charting and multivariate statistics enabled a greater

understanding of morphology, and therefore confidence in the identification of unknown

archaeological samples. The multivariate statistical analysis identified those plant species or

families that could be more easily discriminated from others, and highlighted where extra steps

of visual checking would be required. There is still room for improvement, especially regarding

the development of an automated system for starch classification with greater accuracy,

measured through lowered rates of misclassification from multivariate statistical analysis. The

introduction of new attributes and improved image analysis software may contribute to this

(Coster and Field 2015).

It is hoped that these approaches to the extraction and identification of starch and

vegetative storage parenchyma in this thesis will enable others engaged in the field of

archaeobotany to collect and analyse these micro- and macrobotanical remains. This analysis is

crucial towards elucidating the history of plant use in the Pacific region, where subsistence was

and still is focussed primarily on the cultivation of starchy root, tuber and arboreal species.

Starch and parenchyma derive directly from these organs which have been consumed in the

past, and are still staple dietary components today. These provide clear evidence for diet and

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subsistence, and therefore need to be further studied in terms of more detailed morphological

and also biochemical analysis, as well as archaeobotanical applications. Each new piece of

published research has built on the foundation of others, and this study is no exception.

However, more work is yet to be done to understand starch preservation, contamination and

biases that impact the interpretation of the archaeological record (Barton and Torrence 2015).

This study has provided a baseline for the identification of assemblages from Tongatapu and

these now need to be expanded to other locations in the Pacific through further research,

transparency and consistent application of techniques.

Archaeobotanical research in Tonga and the Pacific

The archaeobotanical analysis in this study was the first to have been conducted in the Tongan

archipelago. However, the limited geographical and temporal scope of this analysis has meant

that a chronology has been created from modelling high-resolution data from narrow time

periods on one small area of an island within the archipelago. Time was a factor in the decision

to restrict analysis to six small test units from three sites, but the primary focus of this project

was to scale back analysis from large horizontal excavations that require coarse-grained

analysis, instead utilising fine-grained archaeobotanical techniques that target extraction of large

quantities of micro- and macrobotanical remains alongside faunal and artefactual material.

The successful recovery of these remains highlights the potential for further

incorporation of these techniques within archaeological research strategies in tropical climates

such as those on Tonga. A range of archaeological deposits were sampled, from dense midden

to buried cultural deposits, and both starch and charred seeds, wood charcoal and endocarp were

recovered from them all. The case study of charred parenchyma from Talasiu especially

emphasises the nature of preservation of these fragile remains and points to the benefits of

analysing them as a record of prehistoric plant use, or to complement microbotanical studies.

The identification of charred remains was used in this study to both confirm and add to the lists

of species cultivated and used within early production systems on Tongatapu. The parenchyma

data added weight to the identification of some controversial or unexpected species at the late-

Lapita site of Talasiu. This study has shown that it is crucial that this relatively unknown type of

macro-remains be incorporated into future archaeobotanical studies that target diet and

subsistence in the Pacific.

The three sites, from which archaeobotanical data was collected within this study, are

well-dated and narrow in time depth, each representing only 100-200 years of occupation. This

was seen as an advantage, enabling detailed data to be collected about subsistence within

‘snapshots’ of Tongan prehistory. Major inter-site variation was not expected, and was not

observed, enabling initial modelling of singular archaeological production systems at each site.

Inter-site variation, on the other hand, provided the basis for temporal comparison of these

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systems and the timing of plant introductions into Tonga. These ‘snapshots’ of plant production

and use from 2750-2650 cal BP, 1300-1000 cal BP, and 800-600 cal BP indicated the rate of

change and interaction occurring during crucial periods in Tongan prehistory. Clearly, more

research is required to fill the gaps, and elucidate in greater detail the role of plants in Tongan

subsistence, and to test the hypothesis for agricultural development proposed here. Would the

modelled systems, the basis for an alternative chronology, hold up under further testing using

newly collected archaeobotanical data? There is only one way to find out and that is through

further and more detailed archaeobotanical studies in the Tongan archipelago, especially at sites

dated to early Lapita occupation and the later end of the Tongan sequence.

271

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294

Appendix A- Species in Reference Collection

Family

Spe

cies

Co

mm

on

nam

eLo

cal nam

e (To

nga)

Origin

sU

tilisation

Ach

ariaceae

Pa

ng

ium

edu

le R

ein

w.

Foo

tball fru

itn

on

eSo

uth

east A

siaA

ltern

ative fo

od

An

acardiace

aeSp

on

dia

s du

lcis P

arkinso

nO

tahe

ite ap

ple

viIn

do

-Malaya

Alte

rnative

foo

d

Ap

ocyn

aceae

Tab

erna

emo

nta

na

au

ran

tiaca

Gau

dich

.n

on

en

on

eTro

pical A

sia/Pacific

Me

dicin

al

Arace

aeA

loca

sia m

acro

rrhiza

(L.) Scho

tt G

iant taro

kap

eTro

pical A

sia or N

ew

Gu

ine

aStap

le fo

od

Am

orp

ho

ph

allu

s pa

eon

iifoliu

s (D

en

st.) Nico

lson

Stink lily

teveM

adagascar to

Ind

o-M

alayaA

ltern

ative fo

od

Co

loca

sia escu

lenta

(L.) Scho

ttTaro

talo

Sou

the

ast Asia

Staple

foo

d

Cyrto

sperm

a m

erkusii (H

assk.) Scho

ttG

iant sw

amp

tarovia

or via

kan

aIn

do

-Malaya

Staple

foo

d

Epip

remn

um

pin

na

tum

(L.) Engl.

Drago

ntail p

lant

no

ne

Old

Wo

rld Tro

pics

Alte

rnative

foo

d

Xa

nth

oso

ma

sag

ittifoliu

m (L.) Sch

ott

Tann

iata

lo fu

tun

aTro

pical A

me

ricaStap

le fo

od

Are

caceae

Co

cos n

ucifera L.

Co

con

ut

niu

Old

Wo

rld Tro

pics

Staple

foo

d, d

rink

Do

me

stic- fibre

, thatch

, vesse

ls, timb

er

Me

dicin

al

Asp

aragaceae

Co

rdylin

e frutico

sa (L.) C

he

v.Ti

siH

imalayas to

No

rthe

rn A

ustralia

Alte

rnative

foo

d

Do

me

stic-fibe

r, thatch

Asp

len

iaceae

Asp

leniu

m sp

. Sp

lee

nw

orts

no

ne

Ind

ian/P

acific Oce

ans

Alte

rnative

foo

d

Co

nvo

lvulace

aeIp

om

oea

ba

tata

s L.

Swe

et p

otato

kum

ala

Ne

w W

orld

Staple

foo

d

Co

nvo

lvulace

aeIp

om

oea

po

lph

a (P

.K. Latz.)

Gian

t swe

et p

otato

no

ne

Au

straliaA

ltern

ative fo

od

De

nn

staed

tiales

Pterid

ium

sp.

Bracke

na

ruh

eG

lob

alA

ltern

ative fo

od

Dio

score

aceae

Dio

scorea

ala

ta (L.)

Gre

ater yam

ufi

Sou

the

ast Asia

Me

dicin

al

Dio

scorea

bu

lbifera

(L.)B

itter yam

ho

iO

ld W

orld

Trop

icsA

ltern

ative fo

od

Dio

scorea

esculen

ta (L.)

Lesse

r yamu

fileiSo

uth

east A

siaStap

le fo

od

Dio

scorea

nu

mm

ula

ria Lam

.Sp

iny yam

pa

lai

Sou

the

ast Asia

Staple

foo

d

Dio

scorea

pen

tap

hylla

(L.)Five

-finge

red

yamlen

aSo

uth

east A

siaStap

le fo

od

Dio

scorea

rotu

nd

ata

Po

ir.W

hite

Gu

ine

a yamn

on

eW

est A

fricaStap

le fo

od

Tacca

leon

top

etalo

ide

s (L.) Ku

ntze

Po

lyne

sian arro

wro

ot

ma

ho

a'a

Trop

ical Asia

Staple

foo

d

Fabace

aeIn

oca

rpu

s fag

ifer (Parkin

son

ex Zo

llinge

r) Fosb

erg

Tahitian

che

stnu

tifi

Ind

o-M

alaya/Me

lane

siaA

ltern

ative fo

od

Pu

eraria

lob

ata

(Willd

.) Oh

wi

Ku

dzu

aka

Eastern

/Sou

the

rn A

siaA

ltern

ative fo

od

Lecyth

idace

aeB

arrin

gto

nia

asia

tica (L.) K

urz

Fish-p

oiso

n tre

efu

tuIn

dian

/Pacific O

cean

sFo

raging/h

un

ting

Ba

rring

ton

ia ra

cemo

sa (L.) Sp

ren

gP

ow

de

r-pu

ff tree

no

ne

Ph

illipin

es

Do

me

stic- soap

Marattiace

aeA

ng

iop

teris sp

.G

iant fe

rns

ha

lufe

Mad

agascar to So

uth

Pacific

Alte

rnative

foo

d

295

Family

Spe

cies

Co

mm

on

nam

eLo

cal nam

e (To

nga)

Origin

sU

tilisation

Mo

raceae

Arto

carp

us a

ltilis (Parkin

son

) Fosb

erg

Bre

adfru

itm

eiN

ew

Gu

ine

aStap

le fo

od

Arto

carp

us h

eterop

hyllu

s Lam

. Jackfru

itn

on

eM

alaysiaStap

le fo

od

Ficus co

pio

sa Ste

ud

.Fig

no

ne

Sou

the

ast Asia/P

acificA

ltern

ative fo

od

Ficus tin

ctoriu

s G

.Forst

Dye

r's figm

asi'a

taIn

dia/P

acific

Alte

rnative

foo

d

Do

me

stic-fibe

r, dye

Mu

saceae

Mu

sa sp

p. (h

ybrid

s)B

anan

as/Plan

tains

fusi

Ind

o-M

alaya/Ne

w G

uin

ea

Staple

foo

d

Myristicace

aeH

orsfield

ia p

ala

uen

sis K

ane

h.

no

ne

no

ne

Palau

Alte

rnative

foo

d

Osm

un

diace

aeTo

dea

sp.

Kin

g fern

no

ne

Sou

th A

frica to N

ew

Zealan

dA

ltern

ative fo

od

Pan

dan

aceae

Pa

nd

an

us tecto

rius

Parkin

son

Screw

pin

efa

/hin

ga

no

Trop

ical Asia to

East Po

lyne

sia

Alte

rnative

foo

d

Do

me

stic- fibre

, thatch

Me

dicin

al

Pip

erace

aeP

iper m

ethysticu

m Fo

rst. f.K

avaka

vaV

anu

atu

Alte

rnative

foo

d/d

rug

Me

dicin

al

Po

aceae

Sacch

aru

m o

fficina

rum

L.Su

garcane

toTro

pical A

siaStap

le fo

od

Ru

biace

aeM

orin

da

citrifolia

L.In

dian

mu

lbe

rryn

on

uSo

uth

east A

sia

Alte

rnative

foo

d

Me

dicin

al

Solan

aceae

Sola

nu

m tu

bero

sum

L.P

otato

no

ne

Ne

w W

orld

Staple

foo

d

Zingib

erace

aeC

urcu

ma

lon

ga

L.Tu

rme

rica

ng

oSo

uth

east A

siaD

om

estic-d

ye

Zing

iber zeru

mb

et (L.) Ro

scoe

ex Sm

.Sh

amp

oo

ginge

ra

ng

oa

ng

oIn

do

-Malaya/So

uth

ern

Asia

Do

me

stic-sham

po

o

Me

dicin

al

296

Appendix B- Description of Parenchyma

Alocasia macrorrhiza (L.) G. Don: Corm (BG948)

Thin sections

Epidermis- A layer of thick periderm protects a cortical region of around 20 radially organised

rows of angular and elongated cells with very thin cell walls. Below this are two rows of

similarly shaped cells with thicker walls that make up the vascular cambium.

Ground tissue- Interior to this is a wide region of amyliferous parenchymatous tissue through

which run vascular bundles. The parenchyma cells tend to be between 80-130µm in length, and

70-100µm in width. Cells are mostly rounded and isodiametric in dimension (60%), however

around 40% are elongated. Inter-cellular spaces are present but no cell contents were observed

aside from cell nuclei. This was most likely a result of the process of the construction of the

histological thin sections.

Vascular tissues- Vascular bundles are atactostele and so are widely separated and run

apparently randomly through the organ. They are amphicribal concentric in arrangement with

open ends (phloem surrounding the xylem apart from at each end of the bundle). The bundles

range in length from 300-560µm, and 200-450µm in width.

Charred samples

Charred dried- Within the cortex the vascular tissues preserve quite well. The cells within the

conjunctive tissue become more irregularly rounded in shape but the dimensions are much the

same as within the thin section. Cell walls become thicker and the inter-cellular spaces turn to

solid charcoal. The tissues within the pith are altered by the formation of large cavities that

compress the surrounding cells. Some starch granules preserve.

Charred fresh- The tissues are much the same as the sample charred from dried state, apart from

the phloem which has become solid carbon within the cortex.

297

Artocarpus altilis (Parkinson) Fosberg: Fruit (BG947)

(Not vegetative storage parenchyma)

Thin sections

Basic cell morphology and tissue arrangement- An outer epidermis composed of two to three

layers of thickened radially organized rounded and isodiametric cells. Below this is a wide

region of amyliferous parenchymatous tissue through which run vascular bundles. These

parenchyma cells tend to be between 40-60µm in length, and 30-40µm in width. Cell shape and

dimensions are relatively diverse, but the most common cell combination is rounded and

isodiametric in dimension (40%), however a small number are angular and elongate (25%), or

rounded and elongate (28%). Inter-cellular spaces are present and starch granules and druses

were also observed within cells. Vascular bundles are atactostele and so are widely separated

and run apparently randomly through the organ. The bundles are amphicribal u-shaped in

arrangement (phloem surrounding the xylem in a u-shaped formation), and range in length from

100-600µm, and 70-280µm in width.

Charred samples

Charred dried- Within the vascular tissues, the xylem preserved quite well but the phloem

turned to solid carbon. The epidermis also becomes solid carbon along with many rows of cells

within the ground tissue. The remaining cells within the conjunctive tissue are much the same as

within the thin section.

Charred fresh- The tissues are generally preserved better within the freshly charred sample. The

phloem has turned to solid carbon surrounding the xylem, but the ground and boundary tissues

are still relatively the same morphologically.

Artocarpus altilis (Parkinson) Fosberg: Seed (BG947)


Thin sections

Basic cell morphology and tissue arrangement- An outer thin epidermis composed of only one

layer of radially organised rounded and isodiametric cells with thickened cell walls. Interior to

this is a wide region of amyliferous parenchymatous tissue through which run vascular bundles

of varying sizes. The parenchyma cells tend to be between 60-80µm in length, and 50-65µm in

298

width. Cells are mostly rounded and isodiametric in dimension, however roughly 25% are

elongated. Inter-cellular spaces are present and starch granules and druses were also observed

within cells. The pith is composed of sclerenchyma. Vascular bundles are atactostele and so are

widely separated and run apparently randomly through the organ. They are amphicribal

concentric in arrangement (phloem surrounding the xylem). The bundles range in length from

80-900µm, and 75-360µm in width.

Charred samples

Charred dried- Within the cortex the cells forming the conjunctive tissues have thicker cell walls

and inter-cellular spaces become solid carbon. The cells within the pith are much the same as

within the thin section. The xylem preserved well but the phloem turned to solid carbon during

charring.

Charred fresh-Within the vascular tissues, the xylem preserved quite well but the phloem turned

to solid carbon. The epidermis also becomes solid carbon and large cavities formed in the pith

that compresses the surrounding cells. The remaining cells within the conjunctive tissue are

much the same as within the fresh sample.

Angiopteris sp. :Rhizome (MP1152-005)

Thin sections

Epidermis- An outer epidermis composed of around three layers of radially organised rounded

and elongated cells with thickened cell walls.

Ground tissue- Interior to this is a region of cortical parenchymatous tissue. The parenchyma

cells tend to be between 100-150µm in length, and 85-100µm in width. Cells are a combination

of rounded and elongate in dimension (53%), and isodiametric (47%). Inter-cellular spaces are

present and starch granules were also observed within cells. Within the parenchyma is a wide

region of collenchyma with smaller rounded isodiametric cells and large inter-cellular spaces.

Vascular tissues- A dictyostele arrangement is present, however the vascular bundles could not

be clearly observed within the histological thin sections.

299

Charred samples

Charred dried- The xylem preserves relatively well, but the surrounding phloem turns to solid

carbon along with the fiber sheath. Most conjunctive parenchyma cells become solid carbon, but

some small vessels survive within these. Some starch granules preserve.

Charred fresh-The vascular tissues are much the same as the dried charred sample. Many cells

within the ground tissue flatten and compress, and large cavities forms within the pith. The

epidermis becomes mostly solid carbon.

Asplenium sp.:Rhizome (EU003)

Thin sections

Epidermis- An outer epidermis composed of one layers of radially organised angular and

isodiametric cells with thickened cell walls. Below this is a broad region of approximately seven

to eight rows of fibres that separate the epidermis and the conjuctive tissue within the pith.


cells tend to be between 55-80µm in length, and 45-70µm in width. Cells are rounded in shape

and predominantly isodiametric in dimension (77%), with a smaller percentage being elongate

(23%). Inter-cellular spaces are present within this conjunctive tissue. Starch granules and

druses were also observed within the cell contents.

Vascular tissues- A dictyostele overall arrangement is present, where the vascular chamber is

broken into segments. The segments are amphicribal concentric in arrangement, where the

xylem vessels are surrounded by the phloem. The sizes of these segments differ, with an total

length range of 770-960µm and width range of 390-810µm.

Charred samples

Charred dried and fresh- The xylem preserves relatively well, but the surrounding phloem turns

to solid carbon along with the fiber sheath. Most conjunctive parenchyma cells become

compressed and more angular, especially longitudinally, and some become solid carbon. Many

very small starch grains survived the charring process.

300

Asplenium sp. :Rhizome (MP1152-009)

Thin sections


isodiametric cells with thickened cell walls. Below this is a broad region of fibres that separate

the epidermis and the conjuctive tissue within the pith

Ground tissue- Interior to this is a region of amyliferous cortical parenchymatous tissue. The

conjunctive parenchyma cells are relatively large compared to other ground tissue observed

within the comparative collection. They range from 115-175µm in length, and 90-130µm in

width. Cells are consistently angular in shape but range markedly in dimension. Around 53%

are isodiametric and 47% are elongated. Inter-cellular spaces are present and starch granules

were also observed within cells.

Vascular tissues- A dictyostele arrangement is present, where the vascular chamber is broken

into segments. The segments are amphicribal concentric in arrangement, whereby the xylem is

surrounded by the phloem, and range in length from 160-950µm and width from 110-570µm.

Charred samples

Charred dried- The xylem preserves relatively well, but the surrounding phloem turns to solid

carbon along with the fiber sheath. Tension fractures divide the conjunctive parenchyma cells

which mostly turns to solid carbon, especially within the periderm.

Charred fresh- The vascular tissues are much the same as for the dried charred sample, however

the ground tissue preserves much better in the fresh sample. The morphology of the cells is

angular and broadly isodiametric. Some compression of cells is visible, and the periderm

becomes mostly solid carbon. Fibre bundles also preserve.

301

Barringtonia asiatica (L.) Kurz: Fruit (EU2012-06)


Thin sections

Basic cell morphology and tissue arrangement- An outer epidermis composed of one layer of

very small radially organised rounded and isodiametric cells with a thick outer cell wall. Below

this is a row of palisade mesophyll cells. Interior to this is a wide region of amyliferous

parenchymatous tissue. The parenchyma cells tend to be between 55-105µm in length, and 40-

75µm in width. Cells are consistently angular and isodiametric in dimension. Inter-cellular

spaces are present but no cell contents were observable within the thin sections. Vascular

bundles are of the eustele type, and amphivasal concentric in arrangement (xylem surrounding

the phloem) with a fiber sheath. Bundles range in length from 85-160µm, and 85-150µm in

width.

Barringtonia asiatica (L.) Kurz: Seed (EU2012-06)


Thin sections

Basic cell morphology and tissue arrangement- An outer epidermis composed of one layers of


this is a region of cortical parenchyma, roughly the same size and shape as the ground tissue

within the pith. Two rows of vascular cambium separates the cortex and pith. Within the cortical

and conjunctive tissue within the pith, the parenchyma cells tend to be between 50-70µm in

length, and 35-50µm in width. Cells are consistently mostly rounded and isodiametric in

dimension, with roughly 33% being rounded and elongated. Inter-cellular spaces are present and

starch was observable within the cells. Vascular bundles were not observed within the

histological thin sections for this specimen.

Charred samples

Charred dried- Cells within the epidermis, cortex and conjunctive tissue at the pith all survive

charring with very little modification of morphology.

302

Charred fresh- These tissues do not preserve so well when charred from fresh state. The cells

become mostly solid carbon within the cortex and pith, with a few small surviving cells

interspersed throughout. Large cavities form within these regions. The epidermis becomes solid

carbon with cell wall casts.

Barringtonia racemosa (L.) Spreng: Fruit (EU2012-12)


Thin sections

Basic cell morphology and tissue arrangement- A thin epidermis is composed of a single layer

of angular and elongated cells with thick cell walls. Another possible ten rows of rounded and

elongated cortical parenchyma below the epidermis. Within the conjunctive tissue within the

pith, the parenchyma cells tend to be between 45-65µm in length, and 35-50µm in width. Cells

are consistently mostly rounded and isodiametric in dimension, with roughly 28% being

rounded and elongated. Inter-cellular spaces are present but no cell contents were observed.

Vascular bundling is within a eustele arrangement typical of dicotyledons, and is of amphivasal

concentric arrangement. The length range of the bundles is between 150-400µm, and the width

is 110-300µm.

Barringtonia racemosa (L.) Spreng: Seed (EU2012-12)


Thin sections

Basic cell morphology and tissue arrangement- An outer epidermis composed of one layers of


this is a region of cortical parenchyma which is angular and elongated with thick cell walls.

303

Two rows of very small angular and elongated cells make up the vascular cambium which

separates the cortex and pith. Within the conjunctive tissue within the pith, the parenchyma cells

tend to be between 60-85µm in length, and 50-70µm in width. Cells are consistently angular

and broadly isodiametric. Inter-cellular spaces are present and starch was observed within the

parenchymatous cells. No vascular bundles were able to be observed within the histological thin

sections.

Charred samples

Charred dried- The parenchymous cells within the cortex and pith generally remain in good

condition throughout the charring process. However the cells become more rounded, with

thicker cell walls, and inter-cellular spaces become solid carbon. The epidermal cells become

more compressed. Tension fractures form in the pith.


become mostly solid carbon within the cortex and pith, with a few small surviving cells

interspersed throughout. Large cavities form within these regions. The epidermis becomes solid

carbon with cell wall casts.

Colocasia esculenta (L.) Schott: Corm (BG1013)

Thin sections

Epidermis-- An outer thickened epidermis composed of three layers. Below this is a region of

around 20 rows of cortical parenchyma which is angular and elongated with thin cell walls. Two

rows of angular and isodiametric cells with thick cell walls make up the vascular cambium

which separates the cortex and pith.

Ground tissue- Within the conjunctive tissue within the pith, the amyliferous parenchyma cells

are between 70-100µm in length, and 50-75µm in width. Cells are very inconsistent in shape

and dimension. Around 33% of cells are rounded and isodiametric, 28% are rounded and

elongated, 20% are angular and isodiametric, and another 20% are angular and elongated.. Inter-

cellular spaces are present, and starch and raphides (calcium oxylate crystals) were observed

within the cells contents.

304

Vascular tissues- Vascular bundles of both amphivasal concentric and u-shaped arrangement are

present within an atactostele type of overall arrangement within the organ. The length range of

the bundles is 230-580µm, and the width is 160-400µm.

Charred samples

Charred dried- Within the vascular tissues, the xylem preserves very well but the phloem turns

to solid carbon within the surrounding xylem. The cells walls within the conjunctive tissues of

the pith become much thicker and the tissues become more vesicular. The epidermis is mostly

turned to ash and shed. Where these cells do survive the preservation is very good and

morphology does not differ much from the thin sections.

Charred fresh- The tissues charred from fresh state becomes more compressed, with inter-

cellular spaces becoming solid carbon. Large cavities form within the pith. The vascular tissues

survive in much the same form as for the dry charred sample.

Cordyline fruticosa (L.) A.Chev: Stem (EU006)

Thin sections

Epidermis-- An outer thickened epidermis and below this is a region of cortical parenchyma

which is rounded and isodiametric with thin cell walls. There is no obvious vascular cambium

which separates the cortex and pith.

Ground tissue- Within the pith, the parenchyma cells are between 55-75µm in length, and 40-

55µm in width. Cells are consistently angular in shape but vary in dimension. Around 55% of

cells are isodiametric and the remaining 45% are elongated. Inter-cellular spaces are present, but

no cell contents were observed apart from the cell nuclei.

Vascular tissues- Vascular bundles of amphivasal concentric arrangement are present within an

atactostele type of overall arrangement within the organ. The length range of the bundles is 200-

300µm, and the widths are between 100-200µm. Fibres also sheath each of the vascular

bundles.

Charred samples

Charred dried- The phloem within the vascular bundles becomes a cavity surrounded by xylem

and fibres. Large cavities also form between these bundles in many places. Elsewhere the cells

305

become more compressed. The epidermis turns to solid carbon with casts of cell walls on the

exterior surface.


become compressed, folded and flattened within the cortex and pith, with a few small surviving

cells interspersed throughout. Pitting is visible on the inside of the cells. Large cavities form

within these regions of conjunctive tissue. The epidermis becomes solid carbon with cell wall

casts.

Cyrtosperma merkusii (Hassk.) Schott: Corm (EU2012-

09)

Thin sections

Epidermis- Could not be viewed within the histological thin sections.

Ground tissue- The amyliferous parenchyma cells that form the conjunctive tissue are between

40-80µm in length, and 30-50µm in width. Cells are consistently rounded in shape but vary in

dimension. Around 65% of cells are elongated and the remaining 35% are isodiametric. Inter-

cellular spaces are present, and starch granules were observed within the cell contents.

Vascular tissues- Vascular bundles of amphivasal arrangement with open ends are present

within an atactostele type of overall arrangement within the organ and so being present at

random intervals and locations within the organ. The length range of the bundles is 300-500µm,

and the widths are between 200-300µm.

Charred samples

Charred dried- The phloem within the vascular bundles becomes compressed and solid carbon is

some places, surrounded by xylem. The vascular bundles tend to break away from the

surrounding tissue leaving a large cavity. Large cavities also form between the conjunctive

tissues in many places. Elsewhere the cells are preserved well but the tissue becomes more

vesicular overall.

Charred fresh- The fresh charred sample turned to ash.

306

Dioscorea alata (L.): Tuber (EU0013)

Thin sections

Epidermis- An epidermis consisting of four layers of angular and elongated cells with thick cell

walls.

Ground tissue- Below this is a region of amyliferous parenchyma cells that form the conjunctive

tissue. These are between 80-110µm in length, and 50-75µm in width. Cells are consistently

rounded in shape but vary in the regularity of shape and dimension. Approximately 28% of cells

are irregularly rounded in shape and elongated in dimension. The remainder are rounded and

elongated (45%) or isodiametric (29%). Inter-cellular spaces are present, and many starch

granules were observed within the cell contents.

Vascular tissues- Vascular bundles are of closed collateral arrangement and are present within

an atactostele type of overall arrangement within the organ and so being present at random

intervals and locations within the organ. The length range of the bundles is 230-880µm, and the

widths are between 85-340µm.

Charred samples

Charred dried- The phloem within the vascular bundles becomes a cavity abutting the xylem

within the collateral bundle. Large cavities also form within the pith. Elsewhere the cells

become more irregularly shaped with thin walls. Many large starch granules are preserved

within the cells.

Charred fresh- The cells within the cortex become mostly solid carbon that have amalgamated

with inter-cellular spaces, with a few small cells interspersed. Large cavities form within these

regions of conjunctive tissue. Starch is preserved with the cells. Vascular bundles are preserved

in much the same form as for the sample that was dry charred.

307

Dioscorea bulbifera (L.): Aerial bulbil (BG942)

Thin sections

Epidermis- One layer of thickened epidermis. Below this is a region of cortical parenchyma

cells that are rounded and broadly isodiametric with thick cell walls. Many intercellular spaces

are also present between cells. A region of vascular cambium separates the parenchyma within

the cortex and the pith. This is made up of five rows of angular and elongated cells.

Ground tissue- The amyliferous parenchyma within the pith are between 95-130µm in length,

and 75-100µm in width. Cells are consistently rounded in shape but vary in dimension.

Approximately 62% of cells are rounded in shape and isodiametric in dimension. The remainder

are rounded and elongated. Inter-cellular spaces are not present within the conjunctive tissue,

but many starch granules were observed within the cell contents.

Vascular tissues- Vascular bundles could not be observed within the histological thin sections.

Charred samples

Charred dried- The epidermis becomes solid carbon during charring. Cells within the

conjunctive tissues of the pith remain rounded and isodiametric but the walls thicken and inter-

cellular spaces become solid carbon. Large cavities form throughout the ground tissue.

Charred fresh- The boundary and ground tissues are mostly the same as for the sample charred

from dried state, however tension fractures and larger cavities form.

Dioscorea esculenta (L.): Tuber (EU020)

Thin sections

Epidermis- The epidermal region consists of three layers of angular and elongated cells.

Ground tissue- Below this is a region of amyliferous parenchyma which are between 150-

235µm in length, and 100-160µm in width. Cells are consistently rounded in shape but vary in

dimension. Approximately 62% of cells are rounded in shape and isodiametric in dimension.

The remainder are rounded and elongated. Inter-cellular spaces are sometimes present within

the conjunctive tissue but are rare. Many compound starch granules were observed within the

cell contents.

308

Vascular tissues- Vascular bundles are within an atactostele arrangement and so randomly run

throughout the organ. The bundles themselves are of closed collateral arrangement, with no

cambium between the vascular tissues. The length range of the bundles is 150-380µm, and the

widths are between 80-240µm.

Charred samples

Charred dried- The phloem within the vascular bundles becomes a cavity abutting the xylem

within the collateral bundles. Large cavities also form between these bundles within the

conjunctive tissue. Elsewhere the cells become shallower, and the epidermal cells become more

compressed.


become more fragile with thinner cell walls. There is also carbonization of cell walls within

large cavities that form in the ground tissue.

Dioscorea nummularia Lam.: Tuber (EU012)

Thin sections

Epidermis- A thickened epidermis with a layer of five rows of angular and elongated cortical

parenchyma cells.

Ground tissue- Below this is a region of amyliferous parenchyma which are between 75-115µm

in length, and 60-100µm in width. Cells are consistently rounded in shape but vary slightly in

dimension. Approximately 82% of cells are rounded in shape and isodiametric in dimension.

The remainder are rounded and elongated. Inter-cellular spaces are present within the

conjunctive tissue and starch granules were observed within the cell contents.

Vascular tissues- Vascular bundles are within an atactostele arrangement and so randomly run

throughout the organ. The bundles themselves are of closed or open collateral arrangement, with

a cambium separating the vascular tissues. The length range of the bundles is 155-435µm, and

the widths are between 100-250µm.

Charred samples

Charred dried- The parenchyma cells within the cortex become more irregularly shaped, while

those in the pith mostly retain the original morphology. The vascular cambium becomes a

309

tension fracture and separates the cortex from the pith. Within the vascular tissues, the phloem

either becomes a cavity or survives in original condition.

Charred fresh- The vascular and conjunctive tissues become more vesicular when charred from

fresh state. The cell walls merge in places and become areas of solid carbon.

Epipremnum pinnatum (L.) Engl.: Corm (EU011)

Thin sections

Epidermis- A thickened single-layer peridermis lies above a region consisting of around five

rows of angular and elongated primary cortical parenchyma cells with thin cell walls. Another

five rows of similarly shaped cells compose a region of secondary cortex. A row of vascular

cambium that consists of one layer of rounded and elongated cells.

Ground tissue- Below this is a region of conjunctive tissue within the pith, consisting of

amyliferous parenchyma cells which are between 70-95µm in length, and 50-70µm in width.

Cells are consistently rounded in shape but vary slightly in dimension. Approximately 72% of

cells are rounded in shape and isodiametric in dimension. The remainder are rounded and

elongated. Inter-cellular spaces are present within this conjunctive tissue and small sparsely

distributed starch granules were observed within the cell contents.

Vascular tissues- Vascular bundles are within a eustele arrangement. The bundles themselves

are of amphivasal arrangement (phloem surrounded by xylem) in a u-shape pattern. The length

range of the bundles is 220-375µm, and the widths are between 180-300µm.

Charred samples

Charred dried and fresh- Cells within the boundary and conjunctive tissues become compressed

and collapsed around the vascular bundles. Many crystals survive and can be seen within the

cell contents. The xylem and fibre sheaths maintain their original morphology, but the phloem

becomes a cavity within the surrounding xylem vessels.

310

Ficus copiosa Steud.: Fruit (EU-2012-13)


Thin sections

Basic cell morphology and tissue arrangement- Parenchyma cells are consistently rounded in

shape and isodiametric in dimension. Inter-cellular spaces are visible between these. The length

range of these cells is between 40-60µm, and the width range is between 30-45µm. Vascular

bundles of closed collateral and amphicribal u-shaped or concentric form were observed within

a eustele-type arrangement in the fruit. The bundles ranged in length from 70-380µm, and in

width from 60-150µm.

Charred samples

Charred dried and fresh- The parenchyma cells in the cortex of both the fresh and dry-charred

samples become compressed and inter-cellular spaces become solid carbon. Seeds in the pith of

the fruit survive charring and maintain original morphology. The surface morphology also

retains the original ‘peaked’ texture. The ground tissues also become more vesicular overall.

The vascular bundles retain the xylem but the phloem turns to solid carbon.

Ficus tinctoria G.Forst.: Fruit (MP1152-004)


Thin sections

Basic cell morphology and tissue arrangement- Parenchyma cells are consistently angular in

shape but vary in dimension. The majority of cells are elongated in dimension (57%), with just

under half being isodiametric (43%). Inter-cellular spaces are visible between these but no cell

contents were recorded in this particular sample. The length range of these cells is between 55-

90µm, and the width range is between 25-70µm. No vascular bundles were recorded.

311

Charred samples

Charred dried and fresh- The cells in the cortex become solid carbon within the wet-charred

sample, but those in the dry-charred sample are still visible but have become compressed. The

conjunctive tissues closer to the pith collapses during charring from both fresh and dried state.

The seeds survive the charring process. Some original surface texture is also retained in parts.

Ipomoea batatas (L.) Lam.: Tuber (EU023)

Thin sections

Epidermis- A region of periderm consisting of about four rows of radially-orientated angular

and isodiametric cells with thin cell walls.

Vascular Tissues- Below this is a region of parenchymous secondary phloem outside the

cambium consisting of angular cells that range from elongated (28%) to isodiametric (72%) in

dimension. The length range of these cells is 80-115µm, and the widths vary from 60-90µm.

The cambium consists of two rows of angular and elongated cells with slightly thicker walls,

and separates the secondary phloem and xylem. The parenchyma within the secondary xylem

themselves are the same as those within the phloem, however there are regions of anomalous

tertiary growth adjacent to individual vessels. These parenchyma divide both periclinally and

tangentially to produce concentric radiating rings of tertiary xylem.

Charred samples

Charred dried- Parenchyma cells retain much of the original fresh morphology, but become

possibly slightly shallower. Some tension fractures within the conjunctive tissues. The vascular

tissues survive the charring process with no noticeable modification.

Charred fresh- The cells within the cortex become more compressed and often appear fractured

and condensed. The epidermal cells retain original condition, but tension fractures separate

these boundary tissues from the conjunctive tissues in places. Vascular tissues are much the

same as within the dry-charred sample.

312

Inocarpus fagifer (Parkinson ex Zollinger) Fosberg:

Seed (BG955)


Thin sections

Basic cell morphology and tissue arrangement- A layer of endocarp protects the internal region

of amyliferous parenchyma cells. This consists of a row of radially-orientated angular and

isodiametric cells with very thick cell walls. The endocarp also divides the internal

parenchymous tissue through the centre longitudinally. Contained within the bounds of the

endocarp is a region of parenchymous tissue that consists of rounded and predominantly

isodiametric cells (75%), with a length range of 45-100µm and width range of 35-75µm. The

bundling arrangements of vascular tissues are amphicribal u-shaped and are within an

atactostele arrangement whereby the tissues run seemingly randomly throughout the organ.

Charred samples

Charred dried and fresh- The epidermal cells become solid carbon, and the cells within the

conjunctive tissue become more condensed and compressed. Within the vascular bundles, the

xylem preserves well but the phloem becomes solid carbon surrounding these tissues. Large

vessels form in the pith of the organ.

Morinda citrifolia L.: Fruit (BG941)


Thin sections

Basic cell morphology and tissue arrangement- Parenchyma cells are consistently rounded in

shape but vary in dimension. The majority of cells are isodiametric (85%), with a smaller

percentage being elongated (15%). Inter-cellular spaces are visible between these but no cell

313

contents were recorded in this particular sample. The length range of these cells is between 40-

60µm, and the width range is between 30-50µm. Vascular tissues were visible but as this is not

a sample of vegetative parenchyma these bundles did not match any of the typologies used for

root or stem-derived tissues.

Charred samples

Charred dried and fresh- Epidermal cells turn to solid carbon after charring from both dried and

fresh states. The cells within the conjunctive tissues become compressed and cell walls can

collapse. The xylem retains original condition, but the phloem becomes a cavity.

Musa sp.1: Fruit (BG1014)


Thin sections

Basic cell morphology and tissue arrangement- Within the conjunctive tissue, the cells are

irregularly rounded in shape but vary in dimensions. The majority of cells are isodiametric

(85%), with the remainder being more elongated (15%). Inter-cellular spaces are visible, as are

large numbers of duct cavities located between the cells closer to the pith of the organ. The

length range of these cells is 60-90µm, and the widths range from 50-70µm. Small vascular

bundles are present in a eustele overall arrangement and are of amphicribal concentric

arrangement. These bundles range in length from 80-115µm, and in width from 70-100µm.

Many large starch granules are visible within the cell contents.

Charred samples

Charred dried- Many large starch granules survive the charring process. Cells within the

boundary tissues, cortex and pith all mostly collapse. The xylem and fibre bundles retain

original morphology but phloem becomes a cavity.

Charred fresh- The parenchyma cells in the pith retain original condition in terms of shape and

dimensions, but the inter-cellular spaces become cavities alongside the duct cavities. Tension

fractures also form. The cortical region is more collapsed than the pith, with compressed and

fractured cells walls.

314



Thin sections

Basic cell morphology and tissue arrangement- The overall morphology of this sample is very

similar to Musa sp.1 (BG1014) above, however there are several difference in cell size and

shape that can allow differentiation between these two species. Cell lengths range from 73-

215µm, and widths range from 46-170µm. Within the conjunctive tissue, the cells are

irregularly rounded in shape but vary in dimensions. The majority of cells are isodiametric

(75%), with the remainder being more elongated (25%). Inter-cellular spaces are visible, as are

large numbers of duct cavities located between the cells closer to the pith of the organ. Large

vascular bundles are present in a eustele overall arrangement and are of amphicribal concentric

arrangement. These bundles range in length from 220-680µm, and in width from 180-370µm.

Bundles of fibres are disparately located within the organ. Many large starch granules are

visible within the cell contents.

Charred samples

Charred dried and fresh- Within both the samples wet and dry-charred the cell morphology

retains original condition, however inter-cellular spaces become solid carbon. The duct cavities

are also preserved. Some tension fractures form within the pith, and fractures also form along

the vascular cambium. Overall the tissues become more vesicular. Within the vascular tissues,

the phloem becomes a cavity.

Pandanus tectorius Parkinson: Fruit phalange

(EU2011-03)


315

Thin sections

Basic cell morphology and tissue arrangement- The epidermis is composed of one row of

thickened, rounded and isodiametric cells. Below the epidermis is one row of similarly rounded

and isodiametric cells with slightly thinner cell walls. This borders a region of parenchyma

interspersed with vascular bundles surrounded by fibre sheaths. The vascular bundles are more

highly concentrated towards the centre of the phalange and tend to be of amphicribal

arrangement. The length range of these bundles is 260-750µm, and the width range is from 210-

430µm. The amyliferous parenchyma cells form the conjunctive tissue for the organ and are

composed of rounded cells that are mostly isodiametric in dimension (63%). These cells range

in length from 60-100µm and in width from 40-70µm. Inter-cellular spaces are often present

between the cells.

Charred samples

Charred dried and fresh- When charred, cell morphology becomes more irregularly rounded and

slightly collapsed. The fibre sheaths surrounding the vascular bundles retain their original

morphology along with the xylem, but the phloem becomes a cavity in the centre of the bundle.

Pangium edule Reinw.: Fruit (EU2012-02)


Thin sections

Basic cell morphology and tissue arrangement- A periderm forms the outer surface of the organ

and this boundary tissue is made up of around six rows of angular and elongated cells. Below

the periderm is a region of parenchyma interspersed with sclerenchyma. These cells have

relatively thick cell walls. The conjunctive tissue is composed of rounded cells that are mostly

isodiametric in dimension (75%). These cells range in length from 40-80µm and in width from

30-60µm. Inter-cellular spaces are often present between the cells. Xylem vessels are present

near the pith of the fruit.

Charred samples

Charred dried and fresh- The parenchmous cells within the ground and boundary tissues

collapsed in many regions, especially closer to the pith. Other regions have retained the original

316

cell morphology. Within the vascular tissues the xylem vessels have also retained the condition

of the fresh samples, but the phloem has become solid carbon.

Pueraria lobata (Willd): Root (BG974)

Thin sections

Epidermis- A region of periderm consisting of about five rows of radially-orientated angular

and isodiametric cells with thin cell walls.

Vascular tissues- Below this is a region of parenchymous cortex outside the cambium consisting

of rounded cells that range from elongated (35%) to isodiametric (65%) in dimension. The

length range of these cells is 25-45µm, and the widths vary from 20-30µm. The cambium

separates the cortex from the stele, and is composed of an endodermis and pericyle of one row

each. The parenchyma within the secondary xylem themselves are the same as those within the

phloem, however there are regions of anomalous tertiary growth adjacent to individual vessels.

There are many vessels within the xylem which is polyarch in arrangement. Many areas of

tertiary xylem and phloem are also present and are dissected by medullary rays.

Charred samples

Charred dried- Cells in all tissues become compressed, including the secondary xylem which

also becomes fractured and compacted. However, the vessels within the xylem survive charring

very well. Areas of solid carbon form around the stele and tension fractures separate the

vascular tissues along the phloem in places.

Charred fresh- Within the sample charred from fresh state, the preservation of cell morphology

within the stele was much greater. Large xylem vessels also maintain original condition and

structure. The cambium split after a large tension fracture formed along this boundary,

separating the secondary vascular tissues. Some starch granules also survived the charring

process.

317

Piper methysticum G.Forst: Root (EU-2011-02)

Thin sections

Epidermis- A region of periderm consisting of three rows of angular and isodiametric cells that

are thick walled and radially orientated.

Vascular tissues- Below this is cortical amyliferous parenchymous tissue within the primary

tissues, made up of angular and isodiametric cells with very few inter-cellular spaces. Within

this region are wide medullary ray sections made up of ligneous fibres which are thick walled

cells rounded in shape in transverse section, and also xylem vessels. Scanty paratrachial to

vasicentric layers of xylem cells abut these rays and are differentiated by thinner walls and more

angular shape. Bundles of phloem are contained within these areas of xylem. Exterior to the

cambium are further bundles of xylem within the parenchymous tissues. At the centre of the

root is a region of pith. The cells within the pith have a length range of 45-75 µm and a width

range of 35-60µm, and are rounded and isodiametric in dimension with many inter-cellular

spaces.

Charred samples

Charred dried and fresh- When charred from both fresh and dried state, the root of the kava

plant retains much of the original ground and vascular tissue morphology. Cell shape and

dimensions do not change drastically, however some small cavities can form within the

medullary rays of fibres alongside the xylem vessels. Large amounts of starch survive the

charring process within the ground tissues between the rays of fibres, in fact these cells are jam-

packed full of starch.

318

Pteridium sp.: Rhizome (EU002)

Thin sections

Epidermis- An outer epidermis composed of around three layers of radially organised rounded

and elongated cells with thickened cell walls.


cells tend to be between 80-115µm in length, and 65-90µm in width. Cells are a combination of

angular in shape and elongate in dimension (60%), and isodiametric (40%). Inter-cellular spaces

are not present and starch granules were also observed within cells.

Vascular tissues- A dictyostele arrangement is present, however the vascular bundles could not

be clearly observed within the histological thin sections.

Charred samples

Charred dried and fresh- Most tissues become either very compacted or turn to solid carbon

when charred from either fresh or dried state. Large cavities and tension fractures form

throughout the ground and vascular tissues. This species within the genus Pteridium would be

very hard to identify as charcoal.

Solanum tuberosum (L.): Stem tuber

Thin sections

Epidermis- An outer thickened epidermis outside a region of cortical parenchyma. The cortex

consists of about four to five rows of angular and elongate cells with thinner walls. The vascular

cambium is also two layers of angular cells that are slightly more isodiametric

Ground tissue- Interior to this is a region of amyliferous parenchymatous tissue. The

parenchyma cells tend to be between 90-130µm in length, and 70-100µm in width. Cells are

irregularly rounded in shape and elongated in dimension (53%), and isodiametric (47%). Inter-

cellular spaces are not present but many large starch granules were observed within cells.

Vascular tissues- Vascular bundles are bicollateral in arrangement and tend to be long and thin

in overall dimensions. The bundles themselves are arranged within an atactostele orientation,

and so appear to be randomly located within the organ.

319

Spondias dulcis (L.): Fruit (BG981)


Thin sections

Basic cell morphology and tissue arrangement- A region of periderm forms the boundary tissue

for this fruit, composed of an outer thickened periderm, and a cortical region of approximately

five to ten rows of rounded and isodiametric cells with thick cell walls. The thickness of the

periderm varies around the circumference of the organ. The ground tissue within the pith has

thinner cell walls and is angular in shape and primarily elongated in dimension (75%). These

cells within the conjunctive tissue range in length from 85-160µm , and in width from 55-95µm.

There are no inter-cellular spaces visible within the cells, but many starch granules can be seen

within the cell contents. Vascular bundles vary between closed collateral and amphicribal

concentric arrangement within an overall eustele arrangement of these tissues within the organ.

These bundles range in length from 280-400µm, and in width from 140-240µm.

Charred samples

Charred dried- The tissues within the periderm and cortex becomes solid carbon with small

vessels interspersed throughout these regions. Other ground tissues generally maintain the

original cell shape but these can also appear fractured. Within the vascular tissues, the xylem

preserves well but is surrounded by a band of phloem that has turned to solid carbon. Large

cavities form in the pith.

Charred fresh-The tissues within the fresh-charred sample have many of the same modifications

as within the sample dried prior to charring. The periderm and cortex becomes a region of solid

carbon, and some ground tissues within the pith retain the original morphology with angular and

elongated cells. However aside from these areas of cells, the pith mostly becomes highly

vesicular with large cavities and tension fractures.

320

Syzygium malaccense (L.)Merr.: Fruit (EU2012-01)


Thin sections

Basic cell morphology and tissue arrangement- A thin epidermis composed of a single row of

angular and elongated cells, with a thicker exterior wall. Several rows of small cells that are

angular in shape and more isodiametric in dimension are below this within the cortex, followed

by a region of parenchmous ground tissues. The ground tissue is composed of larger angular and

mostly elongated cells (55%), and very few inter-cellular spaces. The length range of these cells

is from 75-120µm, and the width range is from 45-85µm. Vascular bundles are dispersed

throughout the cortex and pith within a eustele arrangement, and are of amphicribal ‘stellate’

arrangement themselves. Within these bundles the xylem forms a stellate polyarch pattern with

the many steles, surrounded by the phloem. These bundles range is length from 250-620µm, and

width from 150-330µm.

Charred samples

Charred dried and fresh- All ground tissues collapse and become fractured, or meld into solid

carbon during the charring process. Within the vascular tissues, the phloem surrounding the

xylem with the stele turns to solid carbon but the xylem maintains its original morphology.

Large cavities form within the ground tissue and tension fractures separate the areas of solid

carbon from each other, creating a highly vesicular overall appearance.

Tabernaemontana aurantiaca Gaudich.: Fruit

(EU2012-05)


321

Thin sections

Basic cell morphology and tissue arrangement- The epidermis a single row of tangentially

flattened angular and elongated cells. Interior to this is a region of amyliferous parenchymatous

tissue. These conjunctive parenchyma cells tend to be between 35-60µm in length, and 25-

40µm in width. Cells are rounded in shape and elongated in dimension (53%), and isodiametric

(47%). Inter-cellular spaces are present but no cell contents were visible within the cell walls.

Vascular bundles are within an eustele arrangement and tend to be amphicribal concentric in

arrangement. The length range of the bundles is 175-370µm, and the range of widths is between

100-230µm.

Charred samples

Charred dried and fresh- The epidermal cells become solid carbon during the charring process

from both dry and fresh states. Fibre bundles survive in original condition. The ground tissues

become collapsed, solid carbon in places and generally more vesicular in appearance. Vascular

tissues were not visible as such within charcoal.

Tacca leontopetaloides (L.) Kuntz: Root tuber

(EU2015)

Thin sections

Epidermis- The periderm consists of three rows of radially orientated angular and elongated

cells with thin cell walls, with the outermost row having a thicker external wall.

Ground tissue- Below this is a region of conjunctive tissue within the pith, consisting of

amyliferous parenchyma cells which are between 70-100µm in length, and 60-80µm in width.

Cells are consistently rounded in shape but vary slightly in dimension. Approximately 83% of

cells are rounded in shape and isodiametric in dimension. The remainder are rounded and

elongated. Many inter-cellular spaces are present within this conjunctive tissue and numerous

starch granules, druses and calcium oxylate crystals are visible within the cell contents.

Vascular tissues- Vascular bundles are within an atactostele arrangement and tend to be

bicollateral in arrangement. The length range of the bundles is 250-530µm, and the range of

widths is between 100-270µm.

322

Charred samples

Charred dried- In general cell morphology is preserved in original condition within the ground

and boundary tissues. Some small cavities form within the pith and cortex, along with a small

number of tension fractures nearer the pith. Bundles of raphides survive the charring process.

Within the vascular tissues the phloem becomes a cavity, but the xylem preserves well.

Charred fresh- Many large cavities form within the pith of the sample charred from fresh state.

The interior of these cavities have the outline of cell walls on the surface. Ground tissues

become more vesicular overall, and the epidermal cells become compressed in shape. Again

small bundles of raphides survive within cells in the ground tissues.

Todea sp.: Rhizome (EU004)

Thin sections


isodiametric cells with thickened cell walls. Below this is a broad region of fibres that separate

the epidermis and the conjuctive tissue within the pith


cells tend to be between 75-135µm in length, and 60-105µm in width. Cells are angular in shape

and predominantly isodiametric in dimension (65%), with a smaller percentage being elongate

(35%). Inter-cellular spaces are not present and starch granules were also observed within cells.

Vascular tissues- A dictyostele arrangement is present, where the vascular chamber is broken

into segments.

Charred samples

Charred dried- The ground tissue preserves the charring process in original condition, but the

boundary tissue becomes solid carbon. Within the dictyostele vascular bundles, the xylem

survives however the surrounding phloem becomes solid carbon.

Charred fresh- The charred ground tissue within the fresh-charred sample are similarly in good

original condition. The epidermis and regions of sclerenchyma also mostly retain their

morphology, with some areas of more compressed cells. Bundles of fibres also preserve. The

323

phloem becomes a large cavity within the vascular bundles, leaving only some areas of xylem

cells within the vascular chamber.

Xanthosoma sagittifolium (L.) Schott.: Corm (EU-2012-

10)

Thin sections

Epidermis- The periderm consists of four rows of radially orientated angular and isodiametric

cells with thin cell walls, with the outermost row having a thicker external wall.

Ground tissue-. The amyliferous parenchyma cells that form the conjunctive tissue are between

55-80µm in length, and 50-60µm in width. Cells are consistently rounded in shape and

isodiametric in dimension. Inter-cellular spaces are present, and many compound starch

granules were observed within the cell contents.

Vascular tissues- Vascular bundles are within an atactostele arrangement and tend to be

amphivasal concentric in arrangement (phloem surrounded by xylem). The length range of the

bundles is 90-270µm, and the range of widths is between 80-230µm.

Charred samples

Charred dried- Ground tissues survive mostly in original condition, however these become more

vesicular. Bundles of raphides are present within cavities between cells. Tension fractures form

along the vascular cambium, separating the boundary tissues from the ground tissues. The

peridem becomes compressed.

Charred fresh- There is much greater modification of tissues within the sample charred from

fresh state. Areas of ground tissue have survived in original condition, but the majority of these

tissues become solid carbon with many small vesicles along with the periderm. Large tension

fractures and cavities form withi the pith with the outlines of cell walls on the interior surfaces.

Within the vascular bundles, the xylem survives but the phloem becomes solid carbon.

324

Zingiber sp.: Rhizome (BG957)

Thin sections

Epidermis- A thickened periderm composes the surface of the rhizome, with around ten rows of

thick walled cells that are rounded and broadly isodiametric in dimension.

Ground tissue-. The amyliferous parenchyma cells that form the conjunctive tissue below the

periderm are between 55-80µm in length, and 50-60µm in width. Cells are consistently

irregularly rounded in shape but vary in dimension. The majority of cells are elongated in

dimension (60%) but a small number are broadly isodiametric (40%). Inter-cellular spaces are

present, but no cell contents were visible during light microscopy of the histological thin

sections.

Vascular tissues- Vascular bundles are within an eustele arrangement and tend to be closed

collateral in arrangement, with a fibre sheath surrounding the bundles. The bundles are more

concentrated in the pith of the rhizome, and more disparate towards the periderm. These range

in length from 296-447µm and width from 240-352µm.

Charred samples

Charred dried and fresh- The vascular bundles are easily identifiable as such within the charred

samples, with the fibre sheath and xylem tissues surviving the charring process in good original

condition. The phloem does not survive and becomes a cavity within these bundles. The

surrounding conjunctive tissue collapses and becomes more irregularly shaped with thin cells

walls. Cells within the periderm also become more compressed.

325

Zingiber sp.: Rhizome (EU007)

Thin sections

Epidermis- The periderm consists of around ten rows of rounded and elongated thick walled

cells that are radially orientated. The exterior wall of the outermost layer is thicker than the

other cell walls. There is a vascular cambium below this that is a single layer of more angular

and elongated cells.

Ground tissue-. The pith of the organ is composed of conjunctive amyliferous parenchyma cells

that are consistently rounded in shape, and predominantly isodiametric in dimension (60%).

This differs from another unidentified species from the Zingiberaceae family that has been

included within the comparative collection and is described above, where a smaller percentage

of cells are isodiametric. The cells range in length from 75-105µm, and 50-85µm in width.

Inter-cellular spaces are present.

Vascular tissues- Vascular bundles are within a eustele arrangement and tend to be amphicribal

concentric in arrangement, with a fibre sheath surrounding the bundles. The bundles are more

concentrated in the pith of the rhizome, and more disparate towards the periderm. These range

in length from 160-309µm and width from 112-240µm.

Charred samples

Charred dried and fresh- The xylem within the vascular bundles survive the charring process in

good original condition, however the phloem and fibre sheath does not survive and become

solid carbon surrounding these bundles. The surrounding conjunctive tissue mostly becomes

compressed but there are regions of surviving cells with original morphology between these

bands of compressed cells. Cells within the periderm become solid carbon with small vesicles.

326

Appendix C- Starch Images

Alocasia macrorrhiza (L.) G.Don: Corm (BG948)

Amorphophallus paeoniifolius (Dennst) Nicolson: Corm (YEN)

Artocarpus altilis (Parkinson) Fosberg: Fruit (BG947)

Barringtonia asiatica (L.) Kurz: Fruit (EU2012-06)

327

Colocasia esculenta (L.) Schott: Corm (BG1013)

Curcuma longa L.: Rhizome (EU-2008-01)

Cyrtosperma merkusii (Hassk.) Schott: Corm (EU2012-09)

Dioscorea alata (L.): Tuber (EU0013)

Dioscorea bulbifera (L.): Aerial bulbil (BG942)

328

Dioscorea esculenta (L.): Tuber (EU020)

Dioscorea nummularia Lam.: Tuber (EU012)

Dioscorea pentaphylla (L.): Tuber (YEN)

Inocarpus fagifer (Parkinson ex Zollinger) Fosberg: Seed (BG955)

Ipomoea batatas (L.) Lam.: Tuber (EU023)

329

Ipomoea polpha R.W Johnson: Tuber (YEN)

Morinda citrifolia L.: Fruit (BG941)



Piper methysticum G.Forst: Root (EU-2011-02)

330

Solanum tuberosum (L.): Stem tuber

Spondias dulcis (L.): Fruit (BG981)

Tacca leontopetaloides (L.) Kuntz: Root tuber (EU2015)

Xanthosoma sagittifolium (L.) Schott.: Corm (EU-2012-10)

331

Appendix D- Archaeobotanical Research in

the Pacific

Pe

riod

Family

TaxaLo

cation

Bo

tanical re

main

sP

ub

lication

Date

s

Ple

istoce

ne

/Early Ho

loce

ne

Ach

ariaceae

Pa

ng

ium

edu

leD

on

gan C

ave, Se

pik-R

amu

, PN

GSe

ed

Swad

ling e

t al. 1991>5,500 B

P

Arace

aeA

loca

sia lo

ng

ilob

a/C

yrtosp

erma

merku

siiN

iah C

ave, M

alaysiaStarch

Paz an

d B

arton

2007<40,000 B

P

Alo

casia

ma

crorrh

izaK

ilu C

ave,B

uka Islan

d, So

lom

on

Is.Starch

Loy e

t al. 199228,000 cal. B

P

Co

loca

sia escu

lenta

Kilu

Cave

,Bu

ka Island

, Solo

mo

n Is.

StarchLo

y et al. 1992

28,000 cal. BP

Niah

Cave

, Malaysia

Pare

nch

yma

Paz an

d B

arton

200723,850-23,020 cal. B

P

Ku

k Swam

p, P

NG

StarchD

en

ham

et al. 2003

10,220-6440 cal. BP

Lake W

anu

m, P

NG

Po

llen

Hab

erle

1995~ 9,000 B

P

Bu

rserace

aeC

an

ariu

m sp

p.

Do

ngan

Cave

, Sep

ik-Ram

u, P

NG

See

dSw

adlin

g et al. 1991

>5,500 BP

Eup

ho

rbiace

aeA

leurites m

olu

ccan

aD

on

gan C

ave, Se

pik-R

amu

, PN

GSe

ed

Swad

ling e

t al. 1991>5,500 B

P

Dio

score

aceae

Dio

scorea

ala

ta

Niah

Cave

, Malaysia

StarchP

az and

Barto

n 2007

<40,000 BP

Dio

scorea

cf.hisp

ida

Niah

Cave

, Malaysia

Pare

nch

yma

Paz an

d B

arton

200721,130 cal. B

P

Dio

scorea

sp.

Ku

k Swam

p, P

NG

StarchD

en

ham

200710,220- 9910 cal. B

P

Mu

saceae

Mu

sa sp

. (Eum

usa

/Au

stralim

usa

)

Ku

k Swam

p, P

NG

Ph

ytolith

s

De

nh

am e

t al. 2003, 2004;

Fullagar e

t al. 2006;

Wilso

n 1985

10,220-6440 cal. BP

Pan

dan

aceae

Pa

nd

an

us sp

.D

on

gan C

ave, Se

pik-R

amu

, PN

GD

rup

es

Swad

ling e

t al. 1991>5,500 B

P

Sapin

dace

aeP

om

etia p

inn

ata

Do

ngan

Cave

, Sep

ik-Ram

u, P

NG

See

dSw

adlin

g et al. 1991

>5,500 BP

Mid

Ho

loce

ne

- Lapita

Ach

ariaceae

Pa

ng

ium

edu

leM

ussau

Is, PN

GP

ericarp

Kirch

1987,1988, 19893200-200 0 B

P

An

acardiace

aeD

raco

nto

melo

n sp

.A

rawe

Is, PN

GSe

ed

Matth

ew

s and

Go

sde

n 1997

3840-1580 BP

Mu

ssau Is, P

NG

See

dK

irch 1987,1988, 1989

3200-200 0 BP

Spo

nd

ias d

ulcis

Mu

ssau Is, P

NG

End

ocarp

Kirch

1987,1988, 19893200-200 0 B

P

Arace

aeC

olo

casia

esculen

taB

ou

rew

a, FijiStarch

, raph

ide

s, xylem

Ho

rrocks an

d N

un

n 2007

3050-2500 BP

An

ir Island

s, PN

GStarch

Cro

wth

er 2001, 205, 2009

c.3300 BP

Re

ef Islan

ds, So

lom

on

sStarch

Cro

wth

er 2009

c. 3100 BP

Mu

lifanu

a, Samo

aStarch

Cro

wth

er 2009

c. 2750 BP

Cyrto

sperm

a m

erkusii

Uru

piv, V

anu

atuStarch

, raph

ide

s, xylem

Ho

rrocks an

d B

ed

ford

2004;

Ho

rrocks e

t al. 20132700 B

P

Nge

rchau

, Palau

Po

llen

Ath

en

s and

Ward

20014500 B

P

Are

caceae

Co

cos n

ucifera

Araw

e Is, P

NG

End

ocarp

Matth

ew

s and

Go

sde

n 1997

3840-1580 BP

Mu

ssau Is, P

NG

End

ocarp

Kirch

1987,1988, 19893200-2000 B

P

Bo

raginace

aeC

ord

ia sp

.A

rawe

Is, PN

GSe

ed

Matth

ew

s and

Go

sde

n 1997

3840-1580 BP

Mu

ssau Is, P

NG

See

dK

irch 1987,1988, 1989

3200-200 0 BP

Bu

rserace

aeC

an

ariu

m sp

p.

Araw

e Is, P

NG

End

ocarp

Matth

ew

s and

Go

sde

n 1997

3840-1580 BP

Mu

ssau Is, P

NG

End

ocarp

Kirch

1987,1988, 19893200-200 0 B

P

Calo

ph

yllaceae

Ca

lop

hyllu

m in

op

hyllu

mM

ussau

Is, PN

GSe

ed

Kirch

1987,1988, 19893200-200 0 B

P

Co

mb

retace

aeTerm

ina

lia ca

tap

pa

Araw

e Is, P

NG

See

dM

atthe

ws an

d G

osd

en

19973840-1580 B

P

Mu

ssau Is, P

NG

See

dK

irch 1987,1988, 1989

3200-200 0 BP

Cycad

aceae

Cyca

s circina

lisA

rawe

Is, PN

GSe

ed

Matth

ew

s and

Go

sde

n 1997

3840-1580 BP

332

Period Family Taxa Location Botanical remains Publication Dates

Mussau Is, PNG Seed Kirch 1987,1988, 1989 3200-200 0 BP

Dioscoreaceae Dioscorea esculenta Bourewa, Fiji Starch, raphides, xylem Horrocks and Nunn 2007 3050-2500 BP

Vao and Urupiv, Vanuatu Starch Horrocks et al. 2013 3000-2600 BP

Dioscorea nummularia Vao, Vanuatu Starch Horrocks and Bedford 2010 3100-2800 BP

Dioscorea pentaphylla Vao, Vanuatu Starch Horrocks and Bedford 2010 3100-2800 BP

Euphorbiaceae Aleurites moluccana Arawe Is, PNG Seed Matthews and Gosden 1997 3840-1580 BP

Fabaceae Inocarpus fagifer Mussau Is, PNG Pericarp Kirch 1987,1988, 1989 3200-2000 BP

Musaceae Musa sp. Reef Islands, Solomons Starch, phytoliths Crowther 2009 c.3100 BP

Urupiv, Vanuatu Phytoliths Horrocks and Bedford 2011 3000-2700 BP

Matilau, Vanuatu Phytoliths Horrocks et al. 2009 2800-2500 BP

Pandanaceae Pandanus spp. Arawe Is, PNG Drupes Matthews and Gosden 1997 3840-1580 BP

Mussau Is, PNG Drupes Kirch 1987,1988, 1989 3200-200 0 BP

Sapindaceae Pometia pinnata Mussau Is, PNG Seed Kirch 1987,1988, 1989 3200-200 0 BP

Late Holocene Araceae Alocasia macrorrhiza Katem compound, Kosrae Parenchyma Athens et al. 1996 c.1900 BP

Futuna Pollen Piazza and Frimigacci 1991 ~600 BP

Colocasia esculenta Me Aure Cave, New Caledonia Starch Horrocks et al. 2008 2700-1800 BP

Avai'o'vuna Swamp, Vavau, Tonga Pollen Fall 2005; Fall 2010 ca. 2600 BP

Ngofe Marsh, Vavau, Tonga Pollen Fall 2010 ca. 2000 BP

Finpea, Kosrae Pollen Athens et al. 1996 1523-1350 BP

Tangatatau, Mangaia Parenchyma Kirch et al. 1995 788-331 BP

Mauna Kea Adze Quarry, Hawaii Parenchyma Allen 1981, 1984 ~775 BP

La Perouse Bay, Rapanui Starch Cummings 1998 650-150 BP

Te Niu, Rapanui Starch Horrocks and Wozniak 2008 650-150 BP

Stonefields, Auckland Starch, xylem Horrocks and Lawlor 2006 550-380 cal. BP

Nuku Hiva, Marquesas Starch Allen and Ussher 2013 550-350 BP

Rangihoua Bay, NZ Starch Horrocks et al. 2004 ~500 BP

Triangle Flat, NZ Starch Horrocks et al. 2004 430-260 BP

Rano Kau, Rapanui Starch Horrocks et al. 2012 post. 1605-1414 cal. BP

Aspouri Peninsula, NZ Starch, xylem Horrocks et al. 2007 Undated

Motutangi, NZ Starch Horrocks and Barber 2005 Undated

Anaura Bay, NZ Starch Horrocks et al. 2008b Undated

Pitcairn Island Starch, xylem Horrocks and Weisler 2006 Undated

Cyrtosperma merkusii Tafunsak, Kosrae Pollen Athens et al. 1996 1997-1709 BP


Henderson Island, Pitcairn Group Leaf parenchyma Hather and Weisler 2000 post. 950 BP

Tangatatau, Mangaia Parenchyma Kirch et al. 1995 788-331 BP

Arecaceae Cocos nucifera Katem compound, Kosrae Endocarp Athens et al. 1996 c.1900 BP

Tangatatau, Mangaia Endocarp/mesocarp Kirch et al. 1995 788-331 BP

Mauna Kea Adze Quarry, Hawaii Endocarp Allen 1981, 1984 ~775 BP

Nikunau, Kiribati Endocarp Piazza 1998 520-305 BP

Tiwaka Valley, New Caledonia Wood Dotte-Sarout et al. 2013 post. 650 BP

Kaho'olawe/Kuli'ou'ou/Lapakahi/

Anaeho'omalu/Kane'ohe/Kalahuipua'a/

Ka'ahumanu, Hawaii Endocarp, husk Allen 1984 Varied

333


Asparagaceae Cordyline fruticosa Avai'o'vuna Swamp, Vavau, Tonga Pollen Fall 2005; Fall 2010 ca. 2600 BP

Ngofe Marsh, Vavau, Tonga Pollen Fall 2010 ca. 2200 BP

Katem compound, Kosrae Wood Athens et al. 1996 c.1900 BP

Tangarutu, Rapa Wood Prebble and Anderson 2012 900-320 BP

Tangatatau, Mangaia Wood Kirch et al. 1995 788-331 BP

Kahikinui, Hawaii Wood Kirch et al. 2005 460-285 cal. BP

Kaho'olawe/Kuli'ou'ou/Kalahuipua'a, Hawaii Wood Allen 1984 Varied

Boraginaceae Cordia subcordata. Mauna Kea Adze Quarry, Hawaii Wood Allen 1981, 1984 ~775 BP

Nikunau, Kiribati Wood Piazza 1998 520-305 BP


Nuku Hiva, Marquesas Wood Huebert et al. 2010 500-300 BP

Burseraceae Canarium spp. Kalahuipua'a, Hawaii Endocarp Allen 1984 700-200 BP

Calophyllaceae Calophyllum inophyllum Tiwaka Valley, New Caledonia Wood Dotte-Sarout et al. 2013 post. 650 BP

Combretaceae Terminalia catappa Katem compound, Kosrae Parenchyma Athens et al. 1996 c.1900 BP


Convovulaceae Ipomoea batatas Tangatatau, Mangaia Parenchyma Hather and Kirch 1991 ~950 BP


Whangapoua, NZ Starch Horrocks et al. 2007 704-550 cal. BP

Kona, Hawaii Starch, xylem Horrocks and Rechtman 2009 650-325 BP

La Perouse Bay, Rapanui Pollen Cummings 1998 650-150 BP


Stonefields, Auckland Starch Horrocks and Lawlor 2006 550-380 cal. BP

Lapakahi, Hawaii Parenchyma Allen 1984; Rosendahl 1972 525-225 BP

Harataonga Bay, NZ Starch Horrocks et al. 2002 562-386 cal. BP

Rangihoua Bay, NZ Starch Horrocks et al. 2004 ~500 BP

Triangle Flat, NZ Starch Horrocks et al. 2004 430-260 BP


Hamurana Rd, Bay of Plenty, NZ Starch Horrocks et al. 2003 260-160 BP

Pouerua/Puketona, NZ Starch, xylem Horrocks et al. 2004 pre. 150 BP

Avai'o'vuna Swamp, Vavau, Tonga Pollen Fall 2005; Fall 2010 Historic



Pitcairn Island Starch, xylem Horrocks and Weisler 2006 Undated

Cucurbitaceae Lagenaria siceraria Rano Kau, Rapanui Pollen Horrocks et al. 2012 post. 1605-1414 cal. BP

Tangarutu, Rapa Pericarp Prebble and Anderson 2012 900-320 BP

Te Niu, Rapanui Pollen Horrocks and Wozniak 2008 650-150 BP

Harataonga Bay, NZ Pollen Horrocks et al. 2002 562-386 cal. BP

Pouerua/Puketona, NZ Pollen Horrocks et al. 2004 pre. 150 BP

Kaho'olawe/Kuli'ou'ou/

Anaeho'omalu/Kane'ohe/Kalahuipua'a/

Ka'ahumanu, Hawaii Endocarp Allen 1984 Varied

334


Dioscoreaceae Dioscorea alata Halawa, Hawaii Parenchyma Allen 1984 750-450 BP



Dioscorea esculenta Me Aure Cave, New Caledonia Starch Horrocks et al. 2008 2700-1800 BP

Dioscorea sp. Me Aure Cave, New Caledonia Starch Horrocks et al. 2008 2700-1800 BP




Upolu, Samoa Parenchyma

Hather 1994b; Green and

Davidson 1969, 1974 900-540 BP

Euphorbiaceae Aleurites moluccana Kaho'olawe/Kuli'ou'ou/Lapakahi/

Kane'ohe/Halawa/Kalahuipua'a/Anahulu/Ka'ahumanu,

Hawaii Endocarp, seed Allen 1984 Varied

Tangarutu, Rapa Endocarp Prebble and Anderson 2012 900-320 BP

Tangatatau, Mangaia Endocarp Kirch et al. 1995 788-331 BP

Fabaceae Inocarpus fagifer Katem compound, Kosrae Parenchyma Athens et al. 1996 c.1900 BP

Nuku Hiva, Marquesas Wood Huebert 2014 post. 1700

Moraceae Artocarpus altilis Katem compound, Kosrae Parenchyma Athens et al. 1996 c.1900 BP


Malsu, Kosrae Pollen Athens et al. 1996 1264-1150 BP

Papeno'o Valley, Society Islands Wood Orliac 1997 ~650



Nuku Hiva, Marquesas Wood Huebert 2014 682 BP-present

Opunohu Valley, Society Islands Exocarp Kahn and Ragone 2013 ~250 BP

cf. Artocarpus altilis Futuna Pollen Piazza and Frimigacci 1991 ~600 BP

Broussonetia papyrifera Rangihoua Bay, NZ Pollen, phytoliths Horrocks et al. 2004 ~500 BP

Rano Kau, Rapanui Pollen Horrocks et al. 2012 post. 1605-1414 cal. BP

Ficus sp. Tiwaka Valley, New Caledonia Wood Dotte-Sarout et al. 2013 post. 650 BP

Musaceae Musa sp. Rano Kau, Rapanui Phytoliths Horrocks et al. 2012 post. 1605-1414 cal. BP

Tangatatau, Mangaia Leaf parenchyma Kirch et al. 1995 788-331 BP

Kona, Hawaii Phytoliths Horrocks and Rechtman 2009 650-325 BP

Futuna Pollen Piazza and Frimigacci 1991 ~600 BP

Kaho'olawe, Hawaii Wood Allen 1984; McAllister 1933 Unknown

Myrtaceae Syzygium malaccense Tiwaka Valley, New Caledonia Wood Dotte-Sarout et al. 2013 post. 650 BP

Pandanaceae Pandanus tectorius Tangatatau, Mangaia Drupes Hather and Kirch 1991 ~950 BP

Tangarutu, Rapa Drupes/leaf Prebble and Anderson 2012 900-320 BP

Pandanus sp. Katem compound, Kosrae Parenchyma Athens et al. 1996 c.1900 BP

Nikunau, Kiribati Drupes Piazza 1998 520-305 BP

Kaho'olawe/Kuli'ou'ou/Anaeho'omalu

Kane'ohe/Halawa/Kalahuipua'a/

Ka'ahumanu, Hawaii Drupes Allen 1984 Varied

335


Piperaceae Piper methysticum Nuku Hiva, Marquesas Starch Allen and Ussher 2013 550-350 BP

Kaho'olawe/Kuli'ou'ou/Anaeho'omalu/

Kane'ohe/Ka'ahumanu, Hawaii Wood Allen 1984 Varied

Poaceae Saccharum officinarum Kaho'olawe/Kuli'ou'ou/Kalahuipua'a, Hawaii Wood Allen 1984 Varied

Rubiaceae Morinda citrifolia Katem compound, Kosrae Wood Athens et al. 1996 c.1900 BP

Nikunau, Kiribati Wood Piazza 1998 520-305 BP

Mauna Kea Adze Quarry, Hawaii Wood Allen 1981, 1984 ~775 BP

Sapindaceae Pometia pinnata Ngofe Marsh, Vavau, Tonga Pollen Fall 2010 ca. 2500 BP

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