A summary of research publications from the ICFR for 2016 01... · Institute for Commercial...

All ICFR Bulletins have been peer-reviewed.

The recommendations contained in the ICFR Bulletin Series are based on the results of research conducted at the ICFR and reflect our current understanding of the complex inter-relationships involved. The ICFR reserves the right to subsequently modify recommendations in the light of new evidence from ongoing research and no guarantees are provided, either explicitly or by implication. The ICFR must be acknowledged whenever information contained in this document is reproduced or used in any form.

© ICFR 2017

ICFR Bulletin 01/2017

A summary of research publications from the

ICFR for 2016

Compiled by: Sidhika Naidoo and Sally Upfold

ICFR Bulletin Series 01/2017

© ICFR 2017

Table of Contents

ICFR Technical Reports ...............................................................................................................................................................................4

Peer reviewed Papers ..............................................................................................................................................................................14

Other Publications .....................................................................................................................................................................................24

Lectures and Courses ...............................................................................................................................................................................25

Conferences and Symposia ....................................................................................................................................................................33

ICFR Author Index......................................................................................................................................................................................70


© ICFR 2017

A summary of research publications from the ICFR for 2016

Sidhika Naidoo* and Sally Upfold*[email protected]

Institute for Commercial Forestry Research, P O Box 100281, Scottsville 3209

Summary

The following is a summary of publications produced by the Institute for Commercial

Forestry Research (ICFR) including bulletins, technical notes, papers and conference

proceedings during 2016.

Abstracts are presented in the five publication categories; Technical Reports (Bulletins

and Technical Notes), Peer-review Papers, Other Publications, Lectures and Courses,

and Conferences and Symposia, in alphabetical order according to senior author

surname, and are also indexed according to author.


© ICFR 2017

Keywords: 1-Naphthaleneacetic acid (NAA)

Hedge plants

Indole-3-butyric acid (IBA)

Rooting black wattle cuttings

ICFR TECHNICAL REPORTS

The effect of plant hormones and rooting products on rooting success of black wattle (Acacia mearnsii)

hedge plant cuttingsSascha Beck-Pay* and Michael Bairu

*[email protected]


Published as: ICFR Technical Note 07/2016

SUMMARY

This report presents results of an evaluation of seven rooting products for the

improvement of rooting success with Acacia mearnsii. Two products, containing Indole-

3-butyric acid alone or together with 1-Napthaleneacetic acid, statistically significantly

improved rooting of cuttings set relative to the control increasing success from 10% to

25-27%. This experiment must be repeated to confirm benefits are reproducible and

to establish any clone specific effects.


© ICFR 2017

Keywords:Male and female flowers

Reproductive biology

Seed orchard

Flower head composition of black wattle (Acacia mearnsii) inflorescences from selections in a breeding population; the incidence of andromonecy

Sascha Beck-Pay*, Kerry Koen and Michelle Tedder*[email protected]



SUMMARY

There are a number of factors within a seed orchard system that can influence the

level of genetic gain and diversity within the produced seed. Flowering intensity,

flowering patterns and pollinator activity within an orchard are all inter-related and

will determine the potential outcrossing, genetic diversity and level of genetic gain

within the progeny derived from that orchard. This report focusses on an occurrence

observed where some trees within the Acacia mearnsii breeding population produced

predominantly male flowers, commonly known as andromonecy. This occurrence

can contribute to good outcrossing within the orchard but, conversely, may lower

the potential seed yield.


© ICFR 2017

Keywords:E. badjensis

Heritabilities

Provenances

Selection

Eucalyptus badjensis; a potential alternative to temperate commercial eucalypts with

selection and breedingJoel Cele* and Tammy Swain

*[email protected]


Published as: ICFR Bulletin Series 02/2016

SUMMARY

Eucalyptus badjensis was identified in ICFR site-species trials as one of the few species

with commercial potential in the temperate summer rainfall regions of South Africa.

This is because the species has an optimum Mean Annual Temperature (MAT) range

between 14.5 °C and 17 °C and is considered as cold tolerant as E. nitens and

moderately snow hardy. Eucalyptus badjensis is only slightly less frost hardy than

E. macarthurii and E. benthamii, and is as hardy as E. nitens. A breeding programme

to investigate provenance and family differences in the species was initiated in

1993 with the establishment of a 1st series of trials (E93/01) at Woodstock, Lothair and

Geluk, Paulpietersburg. The breeding population was expanded in 2000 with the

establishment of a 2nd E. badjensis trial series (E93/02) planted across three sites, Hlelo

and Blesbokspruit in Piet Retief and Claimont, Bulwer, in year 2000.

There were significant growth differences between the five provenances at full

rotation; with the Cathcart and Glenbog provenances being the top performing

provenances, with Badja being the worst performing provenance at all three sites.

Significant differences exist between the best and below average families at all sites.

Blesbokspruit and Hlelo showed moderate to high heritabilities for dbh (h2 = 0.29 and

0.46, respectively). Several unimproved E. badjensis families performed better than,

or equal to, external controls in this trial series. Results from ICFR site-species trials

indicated that E. badjensis has promising pulp properties, being second to E. smithii

for mean dissolving pulp yield.

Growth and wood property results from the 1st and 2nd trial series confirmed the potential

of E. badjensis as a viable alternative to the commercial species currently grown

at these sites. The range in variation for growth, basic density, pulp and stem form

coupled with moderate to high heritabilities in E. badjensis, indicates that significant

gains can be expected from selection and breeding of superior trees in this species.


© ICFR 2017

Keywords:High density biomass

Nutrient depletion thresholds

Soil nutrient indicator

Inducing soil nutrient decline in a sandstone-derived soil with densely planted Eucalyptus trees

Steven [email protected]



SUMMARY

This report describes first results from a research trial that, as part of a multi-site series,

aims to understand the risk of nutrient depletion in key plantation soils. Soils in the trial

were derived from the Natal Group sandstone. Soil nutrient removal was achieved

by harvest residue removal, followed by annual removal and coppicing of densely

planted trees (10 000 stems ha-1). Tree growth (biomass), foliar nutrient levels, and

soil chemical properties were compared between replicated treatments of nutrient

removal, nutrient retention (as biomass) and nutrient replacement after removal

(fertiliser addition). Estimated nutrient loss after three crops was equivalent to harvesting

between 2 and 12 rotations of stem wood. Cumulative tree biomass growth after three

crops was 25% less after nutrient removal than after nutrient retention or replacement,

but growth differences between nutrient retention and replacement treatments

were not significant. Foliar nitrogen (N), phosphorous (P), potassium (K) and Zinc (Zn)

concentrations declined to below optimal levels across all treatments over the three

crops. Foliar calcium (Ca) concentrations remained constant over the three crops,

while magnesium (Mg) and the remaining micro-nutrients increased. Significantly

lower foliar concentrations of P, K and Zn in the second crop, and K in the third crop

occurred in the nutrient removal treatment. Nutrient retention and replacement

treatments were statistically similar. Total soil N and extractable P in all treatments

were significantly less after three crops than at the start. Soil P and extractable K

was significantly less in the nutrient removal treatment after three crops. These early

results suggest tree growth was limited by a decline in soil nutrient levels due to the soil

being unable to maintain the major cations N, P, K and the micro-nutrient Zn supply,

irrespective of nutrient retention or replacement. Readily extractable soil reserves of

these nutrients are approaching depletion thresholds at this site. It is anticipated that

tree growth will continue at a slower rate in equilibrium with replenishment of readily

available soil nutrients from atmospheric inputs, microbial decomposition and mineral

weathering. Further work will utilise soils from the full trial series with the aim of improving

laboratory-based diagnostic tools to detect nutrient depletion thresholds in the key

plantation forestry soils.


© ICFR 2017

Keywords: Eucalypt

Manual pitting

Mechanisation

Minimal soil tillage

Motor-manual pitting

Manual and mechanical pitting methods compared in eucalypt regeneration in Mpumalanga and the

KwaZulu-Natal MidlandsSteven Dovey

[email protected]



SUMMARY

Soil preparation prior to planting is commonly done by manually digging shallow

pits using a general minimum depth of 25 cm and width of 25 cm. Intensive labour

requirements, inconsistent pit preparation and rising costs of manual pitting operations

have necessitated investigation into more efficient and cost effective pitting methods.

Three trials were established on two sites; one in the KwaZulu-Natal Midlands and

two near Piet Retief in Mpumalanga (comparing summer and winter pitting), to test

the effects of four manual and three motor-manual pitting methods on tree survival,

growth and uniformity. Pitting method had no significant effect on re-establishment

success and subsequent tree performance across all trial sites at 2.5 years after

planting or thereafter. This implies the soil type tested and eucalypt species planted

were resilient to any possible negative tillage effects induced by these implements. No

differences were found between methods for soils pitted during winter and planted the

following summer compared to pitting and planting in summer. Factors other than tree

performance can be considered in choosing pitting methods. Testing a range of soil

textural classes and carbon and moisture contents is required to enable extrapolation

and recommendations for broader soil types and conditions.


© ICFR 2017

Keywords:High density biomass

Nutrient depletion thresholds

Nutrient removal

Soil nutrient indicator

Nutrient supply potential of South African forestry sites: A conceptual framework and novel

experimental approachSteven Dovey

[email protected]



SUMMARY

Past research (local and international) has demonstrated large losses of nutrients from

plantation sites during and after harvesting. A lack of evidence for nutrient-related

growth decline in local plantations, despite evidence in agricultural field crops, implies

that plantation soils are resilient to nutrient loss. Evidence of soil productivity decline

linked with tree productivity is lacking, as soil-based indicators of nutrient supply

potential under plantation forests are inadequate for describing short, medium or

long-term nutrient availability. This report describes a conceptual approach to better

understand these concerns. A novel set of field trials associated with pot experiments

and laboratory-based methods are described, which aim to understand risk of nutrient

depletion in key plantation soils. The field experimental approach uses frequent and

intensive biomass removal, to rapidly deplete soil nutrients (litter and harvest residues

removal) with an annual harvest of trees grown and coppiced at a high planting

density (10 000 stems ha-1). A nutrient exclusion pot study is underway to test single

element depletion, by growing trees in pots filled with soil taken from the field trial

sites. Pots will receive all nutrients required for tree growth, excluding one element

per treatment (minus-one design). Two additional treatments are fully fertilised and

unfertilised controls. Foliar diagnostics will be used to indicate threshold levels of soil

depletion against which laboratory data will be calibrated. The study will compare

tree growth, foliar nutrient levels and soil chemical properties for treatments subjected

to nutrient removal, nutrient retention and replacement after removal through fertiliser

addition. The study aims to provide insight into soil nutrient depletion and develop

laboratory based thresholds as diagnostic tools to detect the onset of nutrient depletion

in key soils. Field trials have been initiated on five contrasting sites with associated pot

trial studies. First cross-site comparisons are expected in 2017.


© ICFR 2017

Keywords: Corymbia henryi

Corymbia hybrids

Drought resistance

Leptocybe invasa

Site-species matching

South Africa

Early performance of Corymbia hybrids in northern, coastal Zululand

Robin [email protected]



SUMMARY

The early results of the first Corymbia hybrid x site interaction trial series conducted in

South Africa are presented on within this document. The seedlots, comprising a range

of hybrids between C. torelliana and C. citriodora subsp citriodora, C. citriodora subsp

variegata and C. henryi, are being tested over two sites contrasting in mean annual

precipitation and productivity potential in northern, coastal Zululand. At 24 months

after planting, based on tree growth and insect pest and disease tolerance, compared

to the industry controls (eucalypt seedlots and inter-specific hybrid clones), many of

the Corymbia hybrid families are showing excellent adaptation to the environmental

conditions. Further regular measurement and assessment of the trials, through to

rotation end, is necessary to determine the true potential of the different Corymbia

hybrid treatments in the trials for commercial forestry in the region.


© ICFR 2017

Keywords: Eucalypt

Pulpwood yield

Regeneration

Wind damage

Planting stock type influences final yield of Eucalyptus smithii pulpwood crop

Andrew [email protected]



SUMMARY

This report presents the final assessment, at age 9 years, for a Eucalyptus smithii trial

measuring the effect of planting stock characteristics on the incidence of wind

damage. Seedlings raised in two container cavity sizes (‘72’ tray or shallow ‘128’

tray type) and two different ages in each tray were compared. Butt sweep was

slightly but measurably greater using shallow ‘128’ trays compared to ‘72’ trays. The

main influence of planting stock was on final yield. Seedlings raised in ‘128’ trays for

4½ months produced significantly less yield (equivalent to 6 wwt ha-1 yr-1 less MAI)

than 3-month-old seedlings raised in the same tray type, or either 4½ or 5½ month

old seedlings raised in ‘72’ trays. This trial illustrates the importance of planting stock

characteristics in realising potential pulpwood yields from a site.


© ICFR 2017

Keywords: Institute for Commercial Forestry Research

Research outputs

Technical reports

A summary of research publications from the ICFR for 2015

Sidhika Naidoo* and Sally Upfold*[email protected]


Published as: ICFR Bulletin Series 01/2016

SUMMARY

This is a summary of publications produced by the Institute for Commercial Forestry

Research (ICFR) including bulletins, technical notes, papers and conference

proceedings during 2015.

Abstracts are presented in the five publication categories; Technical Reports (Bulletins,

Technical Notes and Internal Reports), Peer-review Papers, Other Publications,

Lectures, Seminars and Courses, and Conferences and Symposia, in alphabetical

order according to senior author surname, and are also indexed according to author.


© ICFR 2017

Keywords:Broadleaf selective

Clopyralid

Drift

Grass selective

Herbicide

Lontrel

Non-selective

Overspray

Pantera

Quizalofop-p-tefuryl

RoundUp

The impact of a non-selective and selective herbicides on six-month old Eucalyptus grandis x E. nitens growth

in the KwaZulu-Natal MidlandsLouis Titshall

[email protected]



SUMMARY

Glyphosate is a non-selective systemic herbicide commonly used to control weeds

in forestry re-establishment. Overspray or drift onto trees can lead to reduced growth

and even mortality. This study quantified suppression in growth of a six-month old

clonal Eucalyptus grandis x E. nitens stand in the KwaZulu-Natal Midlands (Ixopo)

when treated with either glyphosate at rates simulating drift or overspray and two

selective herbicides. Three rates of glyphosate were tested (equivalent of 50, 100 and

200 g active ingredient (ai) ha-1) against an untreated control (no herbicide) and two

systemic herbicides; clopyralid (broadleaf selective, equivalent of 250 g ai ha-1) and

quizalofop-p-tefuryl (grass selective, equivalent of 100 g ai ha-1) were applied either

singly or sequentially to the tree canopies. Two weed control treatment factors were

included consisting of full manual weed removal (weedfree) or no weed control

(weedy). The main effect of herbicide application showed that the glyphosate

treatments resulted in significantly reduced growth relative to the other treatments

at 13 months after application, with higher mortality at the two highest glyphosate

rates. The broadleaf and grass selective herbicides were not significantly different to

the untreated control treatment. It is recommended that overspray and drift should

be eliminated when using glyphosate for post-establishment weed control, while

clopyralid and quizalofop-p-tefuryl show potential for overhead full-cover spraying.


© ICFR 2017

Keywords: Harvesting

Simulation

Thinning

Planting geometry

Productivity

System costing

Optimisation

PEER REVIEWED PAPERS

Mechanical pine thinning harvesting simulation: productivity and cost improvements as a result of

changes in planting geometrySimon Ackerman*, Stefan Seifert, Pierre Ackerman and Thomas Seifert

*[email protected]


Published in: Croatian Journal of Forest Engineering: Journal for Theory and Application of Forestry Engineering 37(1): 1-12

ABSTRACT

Traditionally, the removal of entire rows at regular intervals through thinning

compartments has been applied to facilitate access to mechanised timber harvesting

operations in South Africa. These row thinnings have essentially involved the removal

of every 7th row in a standard 2.7×2.7 m planting regime, resulting in a machine trail

width of 5.4 m and a theoretical distance to the furthest tree of 8.1 m.

A simulation study, based on alternative planting geometries, investigated the effect

on harvesting in terms of harvesting productivity, system costs and impact on stand

structure.

Compartments of different planting geometries ranging from 2.7×2.7 m to 2.5×2.9 m,

2.4×3 m and 2.3×3.1 m at two thinning reference ages were simulator generated.

These compartments were then simulator thinned and harvested in the simulation.

Results showed that the boom reach of the harvester is optimised by extending row

removal from the 7th to the 9th row. At the same time, machine trail length per hectare

was reduced by 20%. This creates more productive area for tree growth, potentially

reduced residual stand impacts, and increases the proportion of selectively harvested

trees per hectare. The increased distance between row thinning removals enhanced

the potential volume harvested trail length (m3/m) and in turn led up to a 8% increase in

harvesting productivity, up to a 21% increase in forwarding productivity and a reduction

in total costs of up to 7% when changing planting geometry from 2.7×2.7 m to 2.3×3.1 m

and 2.4×3.0 m, for first and second thinning.


© ICFR 2017

Keywords: Chill unit

Climate modelling

Eucalyptus nitens

Flowering

Remote weather station

Temperature logger

Thermocouple

Monitoring eucalypt bud temperature using mobile temperature loggers

Robin Gardner*, Michael J Savage and Isa Bertling*[email protected]


Published in: Southern Forests: A Journal of Forest Science 78(2): 105-113

ABSTRACT

Winter chilling is a key environmental trigger of floral induction in temperate Eucalyptus.

Over the past two decades, considerable site × eucalypt flowering interaction research

has been undertaken over a range of high elevation (>1 100 m asl) forestry sites in

the South African summer rainfall area. A practical method of accurately monitoring

eucalypt bud temperature at remote sites in these areas was needed for this research.

Utilisation of traditional methods of air and bud temperature measurement were not

viable, due to significant risks of data and meteorological equipment loss posed by

severe weather, vandalism and theft. Between 1996 and 2004, a robust structure for

housing the miniature Hobo® temperature logger (hereafter termed ‘Hobo pole’) was

designed and utilised for in-field monitoring of air temperature in the research trials.

During 2009 and 2010, an experiment was conducted to investigate the relationship

between E. nitens bud temperature (BudT), Hobo pole air temperature (HoboAT)

and radiation screen air temperature (ScrnAT), and develop appropriate calibration

models. Attempts to develop a single model for predicting hourly BudT from hourly

HoboAT over the entire annual period yielded unsatisfactory results (maximum R 2 value

0.49). Separate winter and summer regression models were subsequently developed

for predicting BudT from HoboAT, ScrnAT from HoboAT, and BudT from ScrnAT. In these

regressions, R 2 values were generally slightly higher, and SE values lower, for mid-winter

data than for mid-summer data. In mid-winter, BudT on HoboAT gave the highest R 2

value (0.99) and lowest SE value (0.49 °C) of all regressions. The Hobo logger/Hobo pole

combination, together with developed regression models (presented in this paper),

offers one practical, cost-effective solution for accurately monitoring eucalypt bud

temperature at remote, high-elevation forestry sites in South Africa.


© ICFR 2017

Keywords:Chilling requirement

Cold tolerance

Eucalypt

Eucalyptus smithii

Flower induction

Flowering

Seed orchards

Site-species matching

Investigating optimal site conditions for flower bud production in Eucalyptus smithii orchards

in South AfricaRobin Gardner*, Isa Bertling, Michael Savage and Sidhika Naidoo

*[email protected]


Published in: Australian Forestry 79(2): 137-146

ABSTRACT

Eucalyptus smithii is an important commercial forestry species in South Africa. The

species’ shy and erratic flowering tendencies hinder its genetic improvement and seed

production. Breeders and seed producers are highly dependent on paclobutrazol

(PBZ) applications for encouraging flower and seed production in E. smithii orchards.

During the summer of 2003/04, an E. smithii flowering field trial series was established

across a range of high elevation (1568–1828 m asl), cool temperate (13.8–15.5°C

mean annual temperature (MAT)) commercial forestry sites in South Africa. The main

objective was to investigate the interaction between PBZ and a range of climatic and

landscape factors on E. smithii floral bud (umbel) production. The main aim was to

define optimum environmental conditions for E. smithii umbel production and potential

orchard establishment. In the fifth and sixth years after planting, 64% and 83% of the

control (nil PBZ) grafted trees and 94% and 94% of PBZ-treated trees produced umbels.

In the fifth year, PBZ application increased mean (across-site) umbel production per

tree by 132%. Regardless of whether PBZ was applied or not, mean umbel production

varied markedly across sites. In the absence of PBZ application, E. smithii test orchards

located on south-west facing slopes in high elevation (>1550 m asl) areas at the lower

end of the applied MAT range were generally the most productive on the basis of

umbel crop. The study demonstrated that, through careful site selection, dependency

on PBZ to achieve satisfactory umbel production in reproductively mature E. smithii trees

may be substantially reduced. Within the elevation and MAT ranges applied in the

trial series, E. smithii orchards situated in low positions in the landscape were at high

risk of being severely damaged by frosts.


© ICFR 2017

Keywords: Cationic bridging

Humid subtropical

Management practices

Mean weight diameter

Soil carbon saturation

Soil fertilizer

The effect of 72 years of sugarcane residues and fertilizer management on soil physico-chemical

propertiesSandile Mthimkhulu, Pascal Podwojewski, Jeffrey Hughes, Louis Titshall*

and Rianto Van Antwerpen*[email protected]


Published in: Agriculture, Ecosystems and Environment 225: 54-61

ABSTRACT

This study, carried-out in KwaZulu-Natal, South Africa, investigated changes in selected

soil properties and their effect on aggregation induced by 72 years of residue burning

or mulching, with and without fertilizer application on a sugarcane trial arranged in a

split-plot design with four replications. The main plot treatments were a) green cane

harvesting with all residues mulched, b) cane burnt prior to harvest with cane-tops left

scattered evenly over the plots and c) cane burnt prior to harvest with all the residues

removed from the plots. Split-plot treatments consisted of fertilized and unfertilized plots.

Soil samples for physico-chemical and aggregate stability analysis were collected at

depths of 0–10 and 10–20 cm from 24 plots. In comparison with burning, significant

effects of mulching were only observed on total nitrogen and exchangeable potassium

and sodium, mainly at 0–10 cm. Aggregate stability estimated by mean weight

diameter (MWD), exchangeable cations (especially calcium and magnesium) and

pH were significantly affected by fertilizer application. An increase in acidity and a

decrease in MWD and exchangeable calcium and magnesium on fertilized plots were

attributed to mining of nutrients by sugarcane, nitrification and subsequent base cation

leaching. The significant positive correlation between calcium and magnesium and

MWD, and the lack of correlation between organic carbon (OC) and MWD, indicated

that bases contributed more to soil aggregation than OC. Total carbon and OC

showed no differences across all treatments. It was concluded that (i) annual fertilizer

applications may lead to soil structure deterioration under sugarcane regardless of the

harvesting method practiced and (ii) increasing additions of organic matter (through

mulching) do not always correspond to an improvement of soil aggregate stability

and related soil properties.


© ICFR 2017

Keywords: Poverty

Rural access

Road authorities

Rural road conditions

Socioeconomic impacts

Assessing the conditions of rural road networks in South Africa using visual observations and field-based

manual measurements: a case study of four rural communities in Kwa-Zulu Natal

S’phumelele Lucky Nkomo, Sumaiya Desai and Kabir Peerbhay**[email protected]


Published in: Review of Social Sciences 1(2): 42-55

ABSTRACT

The prioritization and improvement of rural road networks is important in developing

countries in order to uplift the socioeconomic conditions experienced by communities.

So far, limited information exists on the conditions of unpaved or gravels roads,

particularly in rural areas and the associated implications to rural economies. The

present study therefore used visual observations and field-based measurements

to assess the physical, environmental and anthropogenic factors affecting Minor

roads (R3), Collector roads (R4) and Local roads (R5) in four rural communities in

the KwaZulu-Natal Province, South Africa. The function of these road classes is to

provide access from homesteads to main roads that connect rural areas to towns.

In this study, two classification methods were used to rate the severity and extent of

each surface distress on each road class. Results indicate that there was more than

one surface distresses identified and assessed on each road class within the selected

communities. It was noted that all the road classes had moderate to severe surface

distress, except for the R3 road class in Emazabekweni community, reflecting problems

associated with poor drainage systems and maintenance. Visual observation and

field-based methods are useful tools that can aid in identifying and assessing the

physical conditions of unpaved roads, as well as possible environmental, physical

and anthropogenic factors at interplay, especially in resource limited regions. This

study recommended that road authorities should ensure that proper drainage systems

should be well designed; constructed and maintained on all gravel roads in order to

reduce surface deterioration associated with runoff.


© ICFR 2017

Keywords: Eigenvector analysis

Plant invasions

Proximity analysis

Unsupervised random forest

WorldView-2

Mapping Solanum mauritianum plant invasions using WorldView-2 imagery and unsupervised random forests

Kabir Peerbhay*, Onisimo Mutanga, Romano Lottering and Riyad Ismail*[email protected]


Published in: Remote Sensing of Environment 182: 39-48

ABSTRACT

The accurate detection and mapping of plant invasions is important for an

effective weed management strategy in forest plantations. In this study, the utility

of WorldView-2 was investigated to automatically map the occurrence of Solanum

mauritianum (bugweed) found as an anomaly in forest margins, open areas and

riparian zones. The unsupervised methodology developed, proved to be an effective

and an accurate framework in detecting and mapping the invasive alien plant (IAP).

Using the random forest (RF) proximity matrix, similarity measures between pixels were

successfully transformed into scores (Eigen weights) for each pixel using eigenvector

analysis. Neighbourhood windows with minimum variance revealed the most

important information from localized surrounding pixels to detect potential anomalous

pixels. Bugweed occurrence in forest margins, open areas and riparian zones were

successfully mapped at accuracies of 91.33%, 85.08%, and 67.90%, respectively. This

research has demonstrated the unique capability of using an automated unsupervised

RF approach for mapping IAPs using new generation multispectral remotely sensed

data.


© ICFR 2017

Keywords: Feature selection

Fusarium circinatum

Pinus

RF

Random forest

The identification and remote detection of alien invasive plants in commercial forests: An overview

Kabir Peerbhay*, Onisimo Mutanga and Riyad Ismail*[email protected]


Published in: South African Journal of Geomatics 5(1): 49-67

ABSTRACT

Invasive alien plants are responsible for extensive economic and ecological damage in

forest plantations. They have the ability to aggressively manipulate essential ecosystem

structural and functional processes. Alterations in these processes can have detrimental

effects on the growth and productivity of forest species and ultimately impact on

the quality and quantity of forest wood material. Using direct sampling field-based

methods or visual estimations have generally expressed moderate success owing to the

logistical and timely impracticalities. Alternatively, remote sensing techniques offer a

synoptic rapid approach for detecting and mapping weeds affecting plantation forest

environments. This paper reviews remote sensing techniques that have been used in

detecting the occurrence of weeds and the implications for detecting S. mauritianum

(bugweed); one of the most notorious alien plant invaders to affect southern Africa.

Gaining early control of these alien plant invasions would reduce the impacts that may

permanently alter our forested ecosystems, contributing to its successful eradication

and promoting sustainable forest management practices. Furthermore, the review

highlights the difficulties and opportunities that are associated with weed identification

using remote sensing and future directions of research are also proposed.


© ICFR 2017

Keywords: Coppice reduction

Eucalypt

Herbicide application

Reduction operations

Secondary coppice control

The use of glyphosate for the management of secondary coppice regrowth in a Eucalyptus grandis x

E. urophylla coppice stand in Zululand, South AfricaJonathan Roberts, Keith Little and Marnie Light

[email protected]


Published in: Southern Forests: A Journal of Forest Science 78(3): 217-223

ABSTRACT

In South Africa, commercial eucalypt stands may be regenerated through the stepwise

reduction of coppice shoots following felling. The development of secondary coppice

regrowth following these reduction operations results in competition with the remaining

stems, possibly resulting in a reduction in growth. Currently, secondary coppice regrowth

is controlled manually, or through spraying with glyphosate at 0.6% when ca. 0.75 m in

height. No research has been conducted to determine whether alternative rates and/

or timing of application are possible or cost-effective. In 2006 a trial was implemented in

Zululand, South Africa on a recently coppiced stand of Eucalyptus grandis × Eucalyptus

urophylla so as to optimise rates of glyphosate application (0.6%, 1.2% and 1.8%) for

the control of secondary coppice regrowth at various heights (0.5, 1.0 and 1.5 m). Tree

and secondary coppice regrowth variates were measured annually until rotation-end

(9 years, 3 months). The volume of herbicide used, the number of occasions each

treatment was sprayed and associated costs were combined to provide an indication

of the most cost-effective treatment. Although there were no significant differences

in final coppice yield for the various rates of glyphosate and timing of application (as

assessed by the size of the secondary coppice regrowth) tested, treatment efficacy in

terms of treating secondary coppice regrowth increased with an increase in the rate of

glyphosate applied (0% < 0.6% < 1.2% < 1.8%), especially when treated at either 1.0 or

1.5 m in height. The use of glyphosate, irrespective of rate and/or timing of application

(as assessed by secondary coppice regrowth height), proved to be more cost-effective

compared with manual control or the spraying of the secondary coppice regrowth

at 0.75 m height with 0.6% glyphosate. The most cost-effective treatment was 1.2%

glyphosate applied when the secondary coppice regrowth was 1.5 m. If reduced

herbicide use is a major criterion within a company portfolio, then the secondary coppice

regrowth can be manually removed when 1.5 m.


© ICFR 2017

Keywords: Allophane

Halloysite

High-defect kaolinite

Sanidine

Specific surface area

Mineralogy of volcanically-derived, alluvial soils at Moshi, Tanzania

Terri Taylor, Jeffery Hughes and Louis Titshall**[email protected]


Published in: Soil Research 54(8): 926-936

ABSTRACT

Despite intensive commercial agriculture in the rift zone of Tanzania, mineralogical

studies on the soils influenced by volcanic parent materials are scarce. A mineralogical

investigation of the soils and two buried ash layers from an irrigated sugar estate

was undertaken using X-ray diffraction, transmission electron microscopy and

measurements of extractable iron, aluminium and silicon and the specific surface

area (SSA) of the clay fraction. The dominant mineral in the sand and silt fractions was

sanidine. The clay fractions contained mainly high-defect kaolin, illite and K-feldspar,

with small amounts of calcite, talc and gibbsite in some samples. Electron microscopy

revealed the presence of tubular and spheroidal halloysite and <0.5 µm kaolinite

crystals, as well as nanocrystalline material, probably allophane, and volcanic glass.

The amounts of ferrihydrite (0.34–1.84%) and allophane (0.52–6.84%) were low in the

soils but higher in the buried ash layers. The surface areas of the clay fractions were

high (up to 145 m2 g–1) and it was calculated that 5% allophane constituted 22% of the

total SSA. Although all soils were dominated by halloysite and small kaolinite particles,

it is likely that the small amounts of allophane with high SSA has a strong effect on their

physical and chemical properties.


© ICFR 2017

Monitoring the chemistry and monosaccharide ratio of Eucalyptus dunnii wood by near infrared spectroscopy

Chengfeng Zhou, Wei Jiang, Brian Via, Michael Chetty and Tammy Swain**[email protected]


Published in: Journal of Near Infrared Spectroscopy 24: 537-548

ABSTRACT

Determination of wood chemical components such as extractives, lignin and

carbohydrate content by conventional wet chemistry is time consuming and

sometimes hazardous. Near infrared reflectance (NIR) spectroscopy coupled with

multivariate calibration was utilised to offer a fast alternative to wet chemistry methods.

In this study, 70 Eucalyptus dunnii wood samples were collected to investigate the

correlation and modelling potential of using NIR spectra to predict extractives, lignin,

carbohydrate content and ash which were determined with classical methods

(extractives, ash and lignin) and high-performance liquid chromatography (sugars).

Partial least squares regression was used for multivariate calibration. An evaluation

of the results found that ash, extractives and lignin could be predicted with the

strongest prediction diagnostics while mannose and glucose-to-mannose ratio models

exhibited the lowest performance. The robust ability to predict glucose-to-xylose ratio

(r2 = 0.87) provided a unique way to utilise NIR to monitor biomass quality and could

be helpful for the improvement of ethanol and other forest products. The large range

in glucose-to-xylose ratio (2.0 to 4.0), as determined through NIR, suggests that using

xylose content to estimate total hemicellulose content may be unsuitable, though

this type of ratio assumption and analysis is common for softwoods.

Keywords: Calibration

Eucalyptus

Monosaccharide ratio

Near infrared spectroscopy

Prediction


© ICFR 2017

OTHER PUBLICATIONS

A trip to Brazil, and a walk down the memory lanes of forest history

Sidhika [email protected]


Article in Wood Southern Africa & Timber Times magazine: September 2016

ICFR seminars held in October – “Sharing knowledge and expertise across the sector”

Sidhika [email protected]


Article on Forestry South Africa website

New staff at the ICFRSidhika Naidoo

[email protected]


Article in SA Forestry magazine: December 2016


© ICFR 2017

LECTURES AND COURSES

South African Sirex control programme: Biological control agents and progress to date

Philip [email protected]


Lecture at: Nelson Mandela Metropolitan University, BTech Forestry, 2nd year

SUMMARY

The students were lectured on the South African Sirex Control Programme. Philip

Croft explained the cost implications of Sirex tree mortality in terms of the related

increased silviculture expenditure in harvest slash disposal and land preparation for

the future crop.

The solution to the problem was dealt with under five headings, Chemical control,

Biological control, Monitoring, Awareness and Research. Each heading was expanded

to explain how biological control, both nematodes and Ibalia wasps, had been

deployed and the results that had been achieved at Provincial levels. Monitoring

included the use of traps to detect the movement of Sirex, and emergence cages in

the process of determining parasitism.

Examples of the developments within the programme such as risk mapping and

National monitoring were discussed, and the results, at Provincial level were compared.

The classroom discussion then moved to Bergplaas plantation, belonging to MTO,

where the students could see the Sirex and Ibalia wasps in emergence cages at the

emergence depot. A walk into the plantation highlighted the tell-tale signs indicating

the presence of Sirex larvae in affected trees. The tree inoculation process was

demonstrated. The students had the opportunity to release 50 Ibalia leucospoides

wasps in the compartment.


© ICFR 2017

Spatial technologies and forestry case study: Climate change

Ilaria [email protected]


Lecture at: Nelson Mandela Metropolitan University, BTech Silviculture, 4th year

SUMMARY

Mid-term (2050-2080) climate change predictions for Southern Africa indicate an

increase in temperature, regional increase or decrease in rainfall, and an increase

in the intensity and frequency of extreme events such as heat waves, cold spells

and floods. Spatial technologies supply the necessary tools for the development of

scenarios that are particularly important for the understanding of the potential impact

of climate change on forestry. This concept was illustrated through some examples

particularly focused on potential shifts in optimal forestry sites and potential commercial

forestry species distribution.


© ICFR 2017

Spatial technologies and forestry: An introductionIlaria Germishuizen

[email protected]



SUMMARY

This lecture provided the students with a basic understanding of spatial technologies.

The main components of spatial technologies (GPS, GIS and remote sensing) were

described, and examples of their application to forest management were provided,

particularly with regard to data collection and maintenance, map production, data

viewing and querying. GIS based decision support systems (DSS), an integral part of

forest management, were described, with practical examples in the area of silviculture,

site-species matching, environmental management and forest health.


© ICFR 2017

Spatial technologies and forestry case study: Pest and disease risk modelling




SUMMARY

Spatial technologies play a dual role in terms of tree protection, namely monitoring

and mapping of forest biotic and abiotic threats as well as developing models and

forecasts to estimate their potential impact on the forestry landscape.

Monitoring and mapping is carried out by using a combination of remote sensing

(satellite and airborne imagery), GIS and GPS technologies with the aim of producing

maps showing the current spatial distribution and severity of the impact of threats.

Time series change detection methods applied to remotely sensed imagery are widely

used for screening forest health, mapping damage (e.g. fire), and for highlighting

areas that require in-field reconnaissance.

The upkeep of databases recording the occurrence of biotic and abiotic threats is

an essential component of an effective tree protection strategy. This information,

imported into a GIS environment and coupled with the associated contextual data,

provides the basis for the understanding of the factors associated with the occurrence

of threats and for the development of risk models and forecasts.

These concepts were illustrated through Sirex noctilio and other examples.


© ICFR 2017

Spatial technologies and forestry case study: Site classification




SUMMARY

This lecture focused on site classification systems as a platform for management,

research and technology uptake. Site classifications are based on the stratification

of the landscape into relatively homogeneous units with regard to climate, geology

and topography. They provide a framework for the upscaling and downscaling of

information from site to site type/landscape and vice-versa. The ICFR site classification

was described and an example of its application as a research and technology uptake

and decision support system was provided.


© ICFR 2017

Geographic Information Systems: CartographyKabir Peerbhay

[email protected]


Lecture at: University of KwaZulu-Natal, BSc, 2nd year

SUMMARY

This lecture provided the students with an introduction to spatial cartography and

representation. Map projections and measurement of geographical variables was

discussed. The lecture also covered how to interpret topographical maps, orthophotos

and aerial photographs.


© ICFR 2017

Pests and PathogensThobile Nxumalo

[email protected]


Lecture at: Nelson Mandela Metropolitan University, BTech Forestry, 2nd year

SUMMARY

A lecture was given to address the issues on pests and diseases in South African forestry

industry. A brief overview of the south African forest industry and products produced

was given to the students. The challenge is growing exotic species outside their natural

environment which poses a huge threat to the increase of pests and diseases. The

concept of integrated pest management (IPM) was explained to the students and

its application in dealing with ever increasing forest pests and diseases. They were

taken through some of the challenges in dealing with pests and diseases, specifically

environmental issues relating to chemical control for pests which is highly regulated

by Forest Stewardship Council (FSC). Consequently, the development of the National

Forest Protection Strategy whereby IPM is a key component to it. Pest management

tactics were discussed as part of IPM. Important forest pests and pathogens were

discussed as part of the lecture, highlighting some of the successes and application of

IPM, such as the Sirex Project, Wattle Rust Project and Whitegrubs Project at the ICFR.

The lecture also acknowledged collaboration with our industry partners, especially

FABI who focus on the biology of the pests and pathogens. The lecture ended by

using wattle rust project as an example of IPM application and a success story from

the Sirex Control Programme. Students had an opportunity to further discuss the wattle

disease symptoms in Bergplaas farm.


© ICFR 2017

Professional Communication CourseSally Upfold

[email protected]


Presented at: Institute for Commercial Forestry Research, ICFR postgraduate students

SUMMARY

This is an interactive and informal course run informally, with a maximum of 10-15

people per session over 4.5 – 5 hours, where the aim is to elevate the importance of

communication and communication skills. The objective is to help participants become

more professional, confident and competent with respect to their communication

skills, and is customised, working around individual personalities, enhancing strengths

and addressing weaknesses. The course is also focussed on aspects of science and

scientific communication and the importance and relevance of these.

Course content includes:

1. An Introduction to Communication

• The Communication Process

• Planning your Communication

• 7C’s of Communication

• Scientific Communication

• How to Communicate better

• Effective Communication

• Barriers to Effective Communication

2. Verbal and Non-verbal Communication

• Aspects of Voice, Volume & Tone

• Looking at Posture & Movement, Gestures & Body Language

• Establishing Eye contact

• Active Listening

3. Preparing your Presentation

• Planning Methods

• Using Stories to Inspire

• Other Factors

• Using Visual Aids

4. Handling Questions & Answers


© ICFR 2017

CONFERENCES AND SYMPOSIA

Mechanised pine thinning harvesting simulation: Productivity and cost improvements as a result of

changes in planting geometrySimon Ackerman*, Stefan Seifert, Pierre Ackerman and Thomas Seifert

*[email protected]


Presented at: DEMO International and COFE conference, Vancouver Canada, 19-21 September

ABSTRACT

Mechanised harvesting for thinning has traditionally involved the use of row thinning

to provide access into the compartment by heavy machinery and the inter-row area

subsequently receiving a selective thinning. These row thinning have, in most cases,

been applied on the 7th row to a standard 2.7 m x 2.7 m planting geometry.

A simulation study, based on changing the planting geometry in order to investigate

the effect on harvesting in terms of stand impact, simulated harvesting productivity

and harvesting system costs was done. This involved creating sample compartments

of different planting geometries, from the standard 2.7 m x 2.7 m to 2.5 m x 2.9 m,

2.3 m x 3.1 m and 2.4 m x 3 m at thinning reference ages for South Africa. These

compartments were ‘virtually’ thinned and harvested by means of a simulator.

Results showed that the boom reach of the harvester is optimised by extending

row removal from the 7th to the 9th row. At the same time, machine trail length per

hectare was reduced by 20%. This creates more productive area for tree growth,

potentially reduced residual stand impacts, and increases the proportion of selectively

harvested trees per hectare. The increased distance between row thinning removals

enhanced the potential volume harvested trail length (m3/m) and in turn led up to a

8% increase in harvesting productivity, up to a 21% increase in forwarding productivity

and a reduction in total costs of up to 7% when changing planting geometry from

2.7 m × 2.7 m to 2.3 m × 3.1 m and 2.4 m × 3.0 m, for first and second thinning.


© ICFR 2017

Forest operations research at the ICFR: The development of a research strategy

Simon [email protected]


Presented at: ICFR 2nd Annual Research Meeting, Cedara, Pietermaritzburg, 2-3 March

ABSTRACT

The recent dissolution of Forest Engineering Southern Africa (FESA) resulted in the

repositioning of the capacity into the ICFR under the newly established Forest

operations Research project. While many of the components from the FESA activities

have been carried-over in order to run them to completion, there was a need to

identify and develop the focus of this new project area at the ICFR. This presentation

outlines the steps and progress that has been made thus far.

The initial focus of the project is to understand the scope of Forest Operations

Research which will be used to develop the focus for the project at the ICFR, as

well as contribute to a national view that aims to promote wider collaboration and

development within the industry. Developing a broad understanding of the research

at the local and international scale is a key first step to establish the basis for further

strategic developments. This is being done through literature assessments as well as

through consultative stakeholder engagement. Based on the outcomes of this process,

a more detailed strategy will be developed. It aims show how the ICFR can position

the new project area with the available capacity as well as develop the capacity

and the project over time. The goal of this project is to support a sustainable and cost

effective supply of wood through integrated production from nursery to wood yard.


© ICFR 2017

Small grower winch: Steep slope timber extraction tool for small scale timber harvesting



Presented at: Forestry DST-SIF Symposium, Pretoria, 18 November

ABSTRACT

A great deal of potential wood fibre for pulp production is sourced from timber

farmers and small scale or emerging growers. These growers include both farmers

and rural community growers. Rural communities rely heavily on planted woodlots

and harvesting of exotic tree-infested riverine areas for income into the community.

One of the main issues faced by rural timber farmers is harvesting and extraction

of the timber to a point of sale, often the most expensive component of the whole

forestry operation. This is particularly true for subsistence growers where machinery is

not maintained or new enough to operate efficiently. Of all the potential inefficiencies

faced by these rural communities, timber extraction is perhaps most in need of

improvement.

Since 2015, the ICFR and the University of KwaZulu-Natal Bioresources Engineering have

partnered in an academic project for final year agricultural engineering students to

design, build and test small grower winch prototypes, with the ultimate goal being

commercial development. Recently, this project has also attracted funding support

from the DST Forest Sector Innovation Fund.

Objectives of the project are to design, build and test a prototype timber winch for

small scale growers that is:

• Lightweight and easy to use;

• Cheap to purchase, maintain and operate;

• Productive enough to improve the work situation of rural based harvesting

contractors and labour.

The project is in its second year of development and much of the success to date

is due to the support from sponsors and collaborators; NCT, Stihl, UKZN Bioresources

Engineering, Sappi and PEMSA.


© ICFR 2017

The development of a low cost timber winch for small growers




ABSTRACT

The South African forestry industry is entering into a new phase where business units and

land areas are becoming increasingly fragmented. Through this process, operations

and responsibilities may be transferred to the new and emerging land owners and

small growers who may not necessarily have the financial resources and technical

knowledge to effectively manage (grow, harvest and transport) the timber resource

to market.

FESA’s small growers working group was established to assist in the upliftment of small

and subsistence timber growers and contractors through simple and cost-effective

interventions and product development. One of these is the development of a

cost-effective timber winch that was proposed as a production tool to assist small

scale growers and contractors to productively extract timber grown on steep terrain.

The development and prototyping of the winch was established as a collaborative

project with UKZN’s Agricultural Engineering Department forming part of their final

year student training undergraduate curriculum. The design specifications required

of the winch were that it:

• Be lightweight and portable (< 50 kg);

• Have sufficient cable length (at least 60 meters long);

• Have a working extraction productivity rate greater than 3 tons/day;

• Be able to pull in the region of 120 kg (standard pulp logs) simultaneously;

• Cost under R6 000 (excluding drive system); and

• Be driven by a chainsaw.

The test results of this prototype show that it has the potential to increase the average

productivity of manual (labour) extraction by up to three times. Although the final

design did not meet all the design specifications and was not tested infield, the

prototype shows great promise and will be further developed during 2016.


© ICFR 2017

Quantifying genetic variation of the black wattle breeding populations

Michael [email protected]



ABSTRACT

Forest tree improvement heavily relies on systematic selection for desirable traits

based on calculated breeding values and lab-based phytochemical analysis. During

selection-based breeding, emphasis is placed on family origin and pedigree of

individual trees to maintain acceptable levels of genetic diversity within the breeding

populations. However, in open pollinated species such as wattle, the genetic purity

of subsequent generations of trees cannot be accurately established using family

and pedigree information per se, which incurs the risk of relatedness being built within

the breeding material. One of the greatest applications of molecular markers is in

overcoming this problem.

The ICFR black wattle tree improvement programme has a long history of organised

and systematic selection-based breeding. The study populations (SP1, SP2, SP4, SP5,

and SP6) are the result of several cycles of selection and progeny testing. In such

operations, the following questions arise; what is the degree of genetic differentiation,

inbreeding and relatedness in the current breeding population? What does the genetic

structure of these populations look like? Is there enough gene diversity in the current

population such that they can be used for further selection and progeny testing?

In support of the black wattle operational breeding programme, this study attempted

to answer some of these important questions using an SSR-based molecular marker

system. The results of the study indicate the following:

• There is statistically significant but weak genetic differentiation among the

current breeding sub-populations; SP4 highly and SP6 least differentiated;

• There is statistically significant inbreeding within the current breeding

populations; SP5 with the most and SP6 with the least inbreeding;

• The narrow Nei’s genetic distance between individual trees and the mixed

(non-clustered) phylogenetic tree indicates relatedness;

• The populations belonged to two genetic clusters; cluster one comprising

SP1, 2, 5 and 6, and cluster two, SP4

• There is a need to infuse/introduce new genetic material to the current

breeding sub-populations to increase heterozygosity and broaden the genetic

base of the next generation breeding populations.


© ICFR 2017

The quest for rootstocks to improve seed productionSascha Beck-Pay* and Robin Gardner

*[email protected]



ABSTRACT

For several of the temperate eucalypts important to commercial plantation forestry in

South Africa, production of sufficient seed from improved orchards is a major constraint

to deploying genetic gain. An improved understanding of reproductive biology and

how this can be managed in seed orchards is required to improve the consistency,

quantity and quality of the forestry seed produced for the Sector.

Within the Enabling Technologies Project at the ICFR, the objective is to develop

elite clonal seed orchard management protocols that will increase the quantity and

genetic quality of temperate eucalypt seed production from orchards in South Africa.

A number of research focus areas have been identified, with the current focus being

the identification of rootstocks that will improve clonal seed orchard production.

The use of prolific flowering, precocious, inductive or low-chill-requiring rootstocks

could offer numerous advantages to eucalypt breeders and seed producers, with

the ultimate goal of increasing seed yield per unit orchard area.


© ICFR 2017

Investigation into the physical properties of growing media in relation to rooting of cuttings

Sascha [email protected]



ABSTRACT

The primary focus of the vegetative propagation research within the Acacia Tree

Improvement breeding programme at the ICFR, is to develop and optimise rooted

cutting protocols and establish hedge management practices for black wattle (Acacia

mearnsii). In 2015 an experiment was conducted to investigate different rooting media

in order identify problems inhibiting rooting and thus to further optimise rooting take.

Seven different media combinations of coir to perlite were investigated and cuttings

were set from four selections, already established in hedges. Results were recorded

weekly over an eight-week period, where physical properties of the rooting medium

(mass moisture content %, pH, electrical conductivity, air-filled porosity, total porosity,

water holding capacity, container capacity and bulk density) were then compared

against rooting percentages for each of the growing media under investigation. The

results from this investigation will be discussed in the presentation.


© ICFR 2017

Five-year growth performance and wood properties of E. grandis x E. macarthurii hybrids in the summer rainfall

regions of South Africa and SwazilandJoel Cele

[email protected]


Presented at: 11th SAPBA Symposium, Stellenbosch, 8-10 March

ABSTRACT

Global predictions for the next 50-100 years foresee an increase in temperature,

increase or decrease in rainfall, and increase in frequency and intensity of extreme

events. Therefore the development of Eucalypt hybrids that can tolerate these events

is a priority. Eucalyptus grandis is a species of major importance for plantations with

approximately 340 000 ha grown in South Africa. The species has vigorous growth,

and has good rooting ability, and pulping properties, but average to low wood

density and is highly prone to frost damage. Eucalyptus macarthurii is one of the

few cold and frost tolerant eucalypt species commercially planted on colder, high

altitude and low productivity sites in South Africa. Hybrids were developed by crossing

E. macarthurii pollen (ex ICFR) onto E. grandis selections (ex CSIR), and hedges were

established in White River. Growth characteristics (diameter at breast height and

height) were evaluated in the E. grandis x E. macarthurii clones and controls, and

basal area calculated. The top performing clones were sampled for pulp yield and

basic density. Results showed that there were clones that performed better than, or

equal to, the pure species controls for diameter, basal area and height at the sites.

The basic density of the top E. grandis x E. macarthurii clones was higher than that of

the E. grandis control, at sites where it was planted. The pulp yield of the selected top

clones was higher than that of both E. grandis and E. macarthurii, but comparable

to that of E. nitens and E. dunnii. Twenty clones were selected, based on diameter at

breast height, height and pulp yield, for further testing as having commercial potential

for growth on the more temperate sites of the summer rainfall regions of South Africa.


© ICFR 2017

Eucalyptus grandis x Eucalyptus macarthurii hybrids – options for deployment

Joel [email protected]



ABSTRACT

Eucalyptus grandis is historically a very important pulpwood and pole species due to

its rapid growth and well-studied wood properties, and it roots well for production of

cuttings. Unfortunately, this species is highly susceptible to pests such as Leptocybe

invasa, and susceptible to frost and snow damage. In contrast, E. macarthurii, which

exhibits excellent frost tolerance and can be planted on low productivity sites in the

summer rainfall areas of South Africa, has poor pulping properties and very poor

rooting. Therefore, a number of new hybrids were produced using controlled pollination

of E. grandis with E. macarthurii, to try and optimise some of these properties. In the first

phase of the project, the resultant hybrids (Gxmac) were planted across five different

sites in the Cool and Warm Temperate Forestry Regions, and 20 hybrids were selected

based on growth data, pulping properties and basic density.

However, no matter how good the growth and wood properties of a clone are, the

clone cannot be deployed operationally unless it can be propagated economically.

Therefore, rooting studies were done on the selected clones at nurseries in Piet Retief

and Pietermaritzburg. Several factors have been identified as key factors in rooting

Gxmac hybrids and they are as follows: air temperature, root zone temperature,

light levels, planting media, season of cutting, cutting length, condition of hedges

and fertiliser. The period of transition from a completely rootless stem to an actively

growing cutting is critical and needs to be managed and monitored, and the

optimum period for placing Gxmac cuttings is between August and December

because hedge material is actively growing, air temperature is warm and high light

intensity. Leptocybe invasa had a negative impact on the hedges at both nurseries

and a large variation was observed between the clones with regards to tolerance

and susceptibility to this pest. This variation was linked to the different parents used in

the crosses of these hybrids.

Many of the developed Gxmac clones showed good growth, pulping properties and

frost tolerance, as well as acceptable basic density and rooting percentages. Together

with tolerance to L. invasa, this suggests that there is potential to deploy these hybrids

over a range of selected sites in the summer rainfall region in South Africa.


© ICFR 2017

When Sirex larvae and nematodes meet in a conducive fungus zone, the process of

parasitism may occurPhilip Croft

[email protected]



ABSTRACT

My title uses the word “may” occur and that is deliberate. I hope to answer the

following question that has been asked so many times, but has a complicated answer.

How many times must I inoculate an area? The simple answer is “Until parasitism is

reached and maintained”, but when is that step achieved? The parasitism verification

process is done through dissections which results in a parasitism percentage.

The life cycle of the wasp is the starting point with the introduction of nematodes,

either by artificial inoculation or natural distribution through parasitised female

Sirex noctilio wasps.

The nematode, Deladenus siricidicola, has a two phase life cycle, and this is important

to maintain. If it is not maintained then the nematodes can become ineffective at

four different opportunities, namely:

1. The nematode is effective in entering the larvae of the S. noctilio but along the

line they fail to enter the ovaries and enter the eggs, resulting in S. noctilio viable

eggs being produced

2. If the fungus placed in the tree by the female S. noctilio finds the tree environment

unconducive to good growth due to either resin, temperature, moisture etc, then

the poor fungus growth results in small S. noctilio wasps being produced. These

do not fly far, are more than likely poorly parasitised, lazy to oviposit, and create

a poor nematode transport system

3. Artificial inoculations can introduce too many nematodes into the tree, which

impacts on the fungus supply. Each S. noctilio larvae may be too heavily

parasitised and die prematurely in the tree. Under these conditions, the highly

virulent nematodes die in the larvae and the virulent poor nematodes may be

successful in spreading through successfully pupated and emerged wasps.

4. The D. siricidicola within the tree remain fungus feeders and do not enter the

parasitic phase. These nematodes do not parasitise the S. noctilio males and

females and remain in the tree and eventually die with the tree.

To overcome these pitfalls in parasitism, the SASCP have a system to ensure that we do

not intentionally fall into one of these categories. But here we need industry assistance

in keeping the nematode virulence high by supplying sample logs to the emergence

cages. Here the following is checked:

• Emergence cages test for virulence and parasitism

• Log collection sites and parasitism data is collected and given to FABI, annually

• Sites where high parasitism occurs the D. siricidicola are kept and used in new

cultures to breed new stocks of D. siricidicola for inoculation

• Scenario 1, 3 and 4 are prevented from occurring while scenario 2 is climate

and tree dependant


© ICFR 2017

Rotation end effects of large nutrient losses in the Dukuduku process trial

Steven [email protected]



ABSTRACT

Site nutrient supply must be maintained if the productivity of successive rotations is

to be sustained. Nutrients are supplied to trees from soil reserves that are at risk of

becoming depleted through continuous nutrient removals associated with harvesting

and residue management. The risk of nutrient depletion and yield decline of successive

rotations was assessed on the low carbon, dystrophic sandy soil in the subtropical

environment of the Zululand coastal ecosystem. The effects of harvesting intensity,

residue management and fertilisation on nutrient pools and fluxes in the residues, soil

and in a new crop were measured. Residue management included single and double

residue retention, burning, whole tree removal and nutrient replacement (fertiliser

addition). There were substantial nutrient and biomass losses that occurred during

harvesting and residue removal or burning.

Growth was not altered by harvesting intensity and residue management, but was

enhanced in the first two years by fertiliser addition. Soil nutrient levels were not altered

by residue retention, burning, removal or fertiliser addition at six years after planting

or seven years after treatment implementation. Litter layer mass was not significantly

affected any of the treatments from canopy closure onwards.

The apparent lack of a decline in soil nutritional status due to intensive residue

management was partially attributed to atmospheric inputs that added large amounts

of N, K, and Ca. Further soil surface replenishment may have occurred through bio-

geochemical cycling of nutrients from deeper within the regolith through nutrient

uplift by the deeply rooted trees.


© ICFR 2017

The risk of nutrient depletion measured experimentally: Pot trialSteven Dovey

[email protected]



ABSTRACT

The ability of forestry soils to sustain growth and recover from nutrient loss is poorly

understood. There is no link between laboratory-determined nutrient pool size estimates

(diagnostic measures), soil supply potential and the ability of trees to take up and

efficiently utilise nutrients. These knowledge gaps are currently being investigated

through a series of soil nutrient depletion studies that aim to develop an understanding

of soil nutrient supply thresholds that can be related to tree growth responses. The

purpose of this research is developing and providing clearer diagnostic indicators and

measures of changes in site nutritional sustainability. This is currently being tested in

both field and pot experiments. This presentation highlights the findings to-date of the

pot experiment carried-out on a range of soil types that are derived from contrasting

lithology types found in commercial forestry plantations of South Africa.

Soils derived from five major parent materials were chosen for their hypothesised range

in risk of soil fertility decline and subjected to extreme nutrient loss in field trials and a

pot study. The pot study used nutrient exclusion to induce single element depletion

by growing trees in pots filled with soil taken from the five sites. The treatments consist

of fully fertilised pots with all nutrients required for tree growth, unfertilised control (no

nutrients added) and a series of fertilised treatments where a single nutrient element

was excluded while all other nutrient were added. Depletion of various nutrients has

occurred to varying extents in all the soils tested. This has been evident as a reduction

in tree growth and confirmed through visual foliar deficiency symptoms and laboratory

analyses. All soils have depleted nitrogen (N) and to varying degrees, phosphorus (P)

and potassium (K). Low clay soils (Aeolian and Sandstone) are showing visual signs of

zinc depletion. This trial will continue and enable improved interpretation of laboratory

soil data once each element reaches its depletion threshold. Findings from this study

will also be related to the longer term field studies to help develop more rapid site

nutrient risk assessment tools.


© ICFR 2017

Corymbia hybrids – viable alternatives to pest-plagued eucalypt hybrid clones in Zululand?

Robin [email protected]



ABSTRACT

The ICFR has carried out considerable site-taxa interaction research in Zululand/

Maputaland over the past three decades, aimed at identifying alternative eucalypts

for pulpwood production on the coastal plain. The main thrust of the investigations

was to identify suitably adapted alternative taxa for pulpwood production on “dry”

sites in the region. Approximately 20% of the total managed coastal Zululand timber

production area can be classed as dry (mean annual precipitation (MAP) < 900 mm)

and of low productivity potential. Operational planting choices for these sites were

limited. Highly promising taxa emerged from these trials, including Corymbia henryi

(CH), C. citriodora subsp citriodora (CCC), C. citriodora subsp variegata (CCV),

E. longirostrata and E. argophloia. Subsequently, provenance/progeny (F1) trials

and breeding seed orchards of C. henryi and E. longirostrata were established by

the ICFR, and first generation improved seed of either species has recently become

available to the industry.

Coastal Zululand continues to provide challenges to foresters, particularly in the form

of new pest and pathogen arrivals in the region. The damage to the commercial

Eucalyptus hybrids in Zululand, caused by pests such as Leptocybe invasa (Bluegum

chalcid) and Glycaspis brimblecombei (Red gum lerp psyllid), elevated the importance

of the Corymbia taxa (CH, CCC and CCV) and E. argophloia. All latter eucalypt

taxa have to date demonstrated high resistance to L. invasa and G. brimblecombei.

Recently, an opportunity arose to test a range of Corymbia hybrid material, together

with relevant industry controls, in Zululand in collaboration with Queensland DAFF

(Australia). The Corymbia hybrid material had demonstrated excellent commercial

forestry potential in drought-prone areas of tropical and sub-tropical south-eastern

Queensland. In August 2013, the ICFR established two “new generation” site x eucalypt

taxa interaction trials in northern, coastal Zululand on two sites contrasting strongly in

MAP and productivity potential. The Corymbia hybrid material was based on hybrids

between C. torelliana (CT) and CH, CCC and CCV. A limited number of novel, locally-

developed Eucalyptus clones, i.e. hybrids between E. longirostrata and E. grandis and

E. urophylla, were included in the trials. The latter material remains largely untested

within the Zululand coastal plantation forestry environment.

During September 2015, the trials were measured and assessed comprehensively. Since

trial establishment, both sites have recorded annual total rainfall figures well below

MAP. Regardless of the tough growing conditions, several of the Corymbia hybrid

seedlots were performing exceptionally well. Based on these early (2 y) results, the

commercial potential of the Corymbia, in particular that of the inter-specific hybrids,

relative to that of current industry norms for the region is discussed.


© ICFR 2017

Mapping the risk of Leptocybe invasa in South African plantation forests under current and future climate

Ilaria Germishuizen* and Brett Hurley*[email protected]


Presented at: IUFRO Congress for Asia and Oceania, Beijing, China, 14-27 October

ABSTRACT

Since its arrival in 2007, the Blue Gum Chalcid wasp Leptocybe invasa has been

a cause of serious concern for eucalypt growers in South Africa. Outbreaks are

thought to be temperature driven, and occur during the warmer months in the

warm-temperate areas and throughout the year in the warmer, sub-tropical areas. A

potential distribution model was developed using the Maximum Entropy niche-based

modeling (Maxent) technique. The model was also applied to future climate change

scenarios to evaluate the wasp’s potential distribution under future climatic conditions.

Accuracy of prediction was evaluated using the area under the receiver-operating

characteristic curve (AUC). Differences in the AUC between the test and training

areas were used to assess the potential for model overfitting. MaxEnt generated

high accuracy of prediction for L. invasa potential distribution. The small difference

between test and training AUC values (AUCtraining = 0.93; AUCtest = 0.84) indicated

that the model is robust. Higher probability of occurrence was observed in geographic

areas with mild winters and warm springs. When applying the model to future climate

change scenarios, there was a noticeable expansion of climatically optimal areas,

suggesting a potential increase of the threat posed by this pest to South African

eucalypt plantation forests into the future.


© ICFR 2017

Modelling the risk of bark stripping by Chacma baboons (Papio ursinus) in the pine plantations of the

Mpumalanga province, South AfricaIlaria Germishuizen*, Kabir Peerbhay and Riyad Ismail

*[email protected]


Presented at: IUFRO All Division 8 Conference: Forest environment under changing climates and societies, Beijing, China, 24-28 October

ABSTRACT

Conflict between humans and primates is globally on the increase due to the ability

of certain primate species to adapt to transformed environments, often resulting

in damage to agricultural crops and planted forests. Bark stripping of pine trees by

baboons (Papio ursinus) in commercial plantations is challenging the sustainability of

the forestry industry in the Mpumalanga Province of South Africa. Several studies have

investigated the drivers of this behaviour, however, a variety of factors appears to be

linked to this activity. This study applies a machine learning technique, random forests

(RF), to develop a baboon damage risk model by relating environmental predictors to

the presence and absence of baboon damage caused by bark stripping. The random

forests classifier was successful in predicting damage occurrence (F1 score = 0.801;

AUC=0.945). Baboons seem to generally cause more damage in pine stands located

on high productivity sites, where food resources are more abundant and less time

is spent foraging. The model was applied to the pine plantation landscape of the

Mpumalanga province for risk evaluation in support of management decisions and

long term strategy development for the sustainability of the forestry industry in the future.


© ICFR 2017

Risk modelling of pests and pathogens: Why it matters to the forestry sector




ABSTRACT

Productivity losses due to pests and pathogens are one of the main challenges to the

sustainability of the forestry sector, and a wealth of resources are invested towards

their management. During the last decades, the exponential intensification of global

trade and movements has resulted in a drastic increase of new colonisations by pests

and pathogens. Climate change trends for the southern African region indicate a

shift towards warmer temperatures and generally climatic conditions favouring the

spread particularly of insect pests. Hence, the timeous development of integrated

pest and disease management strategies is essential for the sustainability of the sector

into the future. Models evaluating the potential risk posed by a pest or pathogen to

the environment, being transformed or natural, are key components of an integrated

management approach. Apart from serving as a practical tool for decision making,

these models also contribute towards the understanding of the ecology of pests

and pathogens. Moreover, models can be spatially interpreted and have scenario

capability and are able to account for a dynamic environment. The presentation

focuses on two case studies of particular relevance to the forestry sector in South

Africa, the Eucalypt gall wasp Leptocybe invasa and bark stripping by baboons. A risk

model for L. invasa was developed using the Maximum Entropy (MaxEnt) approach.

This method is particularly useful as it requires presence data only, reducing the

classification error due to pseudo-absence. The model is based on 456 points of

presence distributed throughout the current L. invasa distribution range and is adjusted

to account for varying sampling effort within the landscape. Predictors consist in 19

bioclimatic variables. The model outcome is a pixel based percentage risk of L. invasa’s

presence. MaxEnt predicted the risk of L. invasa within the forestry areas adequately

(Area Under Curve (AUC): Training data 0.87, Test data 0.83). The model confirmed

that areas at higher risk are characterized by high temperatures and high levels of

moisture. Plantations located in sub-tropical climates are at higher risk due to suitable

climatic conditions persisting throughout the year, while warm-temperate areas are

more likely to experience seasonal outbreaks.

The second case study illustrates how a similar modelling approach can be adapted to

evaluate the risk of baboon-related damage in the Mpumalanga pine plantations. Bark

stripping by primates is a complex matter occurring in both natural and transformed

environments and the practice, which is in some instances troop specific, has been

attributed to many different and concurring reasons. The purpose of this specific

study was to simply relate the presence and absence of baboon-related damage

to compartment attributes. The model was developed in randomForests, using over

10,000 points of damage presence and absence as training and test dataset and 38

variable predictors. The model predicted the risk of baboon damage with an error of

10.8% (Out Of Bag; CI 95%: 0.88, 0.89) and a Kappa coefficient of 0.74, indicating a

good level of homogeneity between classification results and reference data. Stand

age was the most important variable in predicting vulnerability to baboon damage,

followed by altitude, rain seasonality and Site Index (SI). Interestingly, the habitat

composition surrounding a compartment did not appear to be linked to the presence

of baboon related damage.


© ICFR 2017

Although the model was able to predict with a good level of accuracy the risk of

baboon damage, primates behaviour is very complex and cannot be explained

entirely in terms of resource availability without taking into account factors such

as inter- and intra- troop social dynamics, population structure and other external

pressures that may influence their behaviour.

The two examples illustrated how risk modelling techniques can be successfully used

in very different contexts and for different purposes. They contribute towards the

understanding of a species ecology by evaluating the environmental drivers and

constraints determining the likelihood of a species’ presence and absence or the

occurrence of a specific behaviour. Nevertheless, risk maps are in itself a key tool for

strategic planning. Risk modelling of pests and pathogens is a growing area of research

at the ICFR in collaboration with TPCP-FABI, the industry and government partners.


© ICFR 2017

Forestry Enterprise Simulator Cori Ham and Simon Ackerman*

*[email protected]



ABSTRACT

Smaller growers and non-traditional forestry owners and contractors make up

a significant part of the forestry landscape and are important to the long-term

sustainability of the industry. Profitability and enterprise sustainability of new entrants into

the industry as well as those of medium growers have necessitated a focus on providing

tools and measures to test the viability of forestry operations before investments are

made and to manage the efficiency and production from available forestry land. The

aim of the “Forestry Enterprise Simulator” (ForEntSim) project is to provide a tool with

which the feasibility and profitability of forestry enterprises and the efficiency of value

chains can be tested through value chain simulations. The simulator will encompass

the entire value chain to the point of sale of the end product and is based on the

premise that profitability is dictated by income and costs and that income is a function

of market price and volume. The ForEntSim will address the following objectives i) ex-

ante simulation of new enterprise ventures to test viability and capital requirements; ii)

simulation of existing forestry value chains to identify potential improvements that will

increase profitability and iii) the simulation of the effect of research results on forestry

value chains to define return on research investment.


© ICFR 2017

Frost tolerance and acclimation in woody plants – A review

Mayuri [email protected]



ABSTRACT

The ability of plants to adapt to low temperatures has a major impact on their

distribution and survival. Response to abiotic stress involves changes in a plant’s

transcriptome, proteome, metabolome and lipidome. The process of cold acclimation

has been established as one of the main mechanisms used by plants to achieve

freezing tolerance. Although much research has been conducted in this field, it is still

not fully understood. In this review, the various aspects of how woody plants respond

to low temperatures is discussed with emphasis on their physiological and biochemical

changes; as a background to understanding cold tolerance in Acacia mearnsii (black

wattle). Extreme low temperatures, which often bring about frost damage in trees

such as black wattle, have a major impact on their survival, successful breeding and

commercial deployment. To assist the operational breeding of black wattle for frost

prone areas, advanced screening methods are needed. These include developing

quick and efficient biochemical screening methods such as the use of proteomics.

The objective of this review is therefore two-fold; firstly to understand the mechanisms

by which woody plants achieve frost tolerance and cold acclimation, and secondly

to identify target proteins, which may be developed as markers to screen for frost

tolerance in black wattle.


© ICFR 2017

Gene conservation – status and proposal for the South African plantation forest industry

Arnulf Kanzler, Tammy Swain*, Steve Verryn, Francois van Deventer, Wayne Jones and Zander Myburg

*[email protected]


Presented at: 11th South African Plant Breeding Symposium – ‘Back to the Phenotype’, Stellenbosch, South Africa, 8-10 March

ABSTRACT

Fast-growing tree plantations are cultivated on around 1.2 million hectares and

contribute significantly to the South African economy, supporting around 170,000

jobs and a R25 billion industry. Over the last century, South Africa has been importing,

testing and commercializing a wide range of tree species and populations that have

contributed hugely to the success of the forest industry today. However, climate

change and globalisation has led to increasing abiotic stress, as well as biotic stresses

such as disease and insect attacks, highlighting the need for breeders to be more

proactive to manage rapid environmental and market changes. Consequently, it is

argued that a systematic and well managed national gene conservation strategy for

fast-growing plantation trees is urgently needed and that this should include multiple

role players - including private industry, government and other public institutions such

as universities. A plan is presented that attempts to integrate and compliment the

needs of tree breeders, industry and gene conservation. It ‘should not be directed

at maintaining a forest population in a given state forever, but rather at ensuring the

long-term enhancement of the genetic diversity available to meet future human

needs’. This strategy will need to maximise genetic diversity, both across and within

species; facilitate the rapid transfer of genotypes from conservation banks into

breeding programs as and when needed; and link phenotyping to genetic diversity so

that breeders can understand / quantify the significance and value of the conserved

material. The achievement of these objectives will be dramatically enhanced with

the use of genome-wide DNA genotyping technology (population genomics) along

with other new technologies (such as remote sensing) so that we can better integrate

and utilise phenotypic information from the tree with environmental variables on a

landscape level.


© ICFR 2017

Measuring the impacts of baboon damage on growthMarnie Light

[email protected]



ABSTRACT

Over the last 10-15 years, damage to pine timber plantations by baboons has become

an ever-increasing problem, particularly in the Mpumalanga region. One ICFR trial,

originally established as a Pinus elliottii re-establishment silviculture trial, experienced

repeated baboon damage and was, therefore, no longer suitable for the original

aim of the trial. However, the trial is now being evaluated on a more regular basis

to gather useful data for the quantification of baboon damage and the associated

productivity losses. Together with a larger network of monitoring plots that are currently

being established, this trial provides some very useful data towards research supporting

the development of a sustainable control strategy. Findings, to date, from this trial will

be presented and discussed.


© ICFR 2017

Understanding the impact of wattle rustThobile Mbatha

[email protected]



ABSTRACT

Wattle rust is the disease caused by Uromycladium acaciae. It was first discovered in

2012 near Eston in KwaZulu-Natal Midlands and has since spread throughout the wattle

growing regions in South Africa and across the border to Swaziland. The disease affects

Acacia mearnsii (black wattle) trees of all ages, with varying levels of severity. Little is

known about the pathogen’s biology, or the reasons for the current disease outbreaks.

Furthermore, no estimates of yield loss due to the impact of the disease are currently

known. Therefore, development of efficient management strategies for the pathogen

is an urgent priority. To support this, the ICFR embarked on a study to (i) understand

the impact of wattle rust on black wattle growth; and (ii) seek triggers of the disease

outbreaks relating to the levels of infestation to changes in environment. Exclusion

plot trials were implemented where pathogens and insects were excluded from host

plants through the application of fungicide (azoxystrobin and difenoconazole) and an

insecticide (cypermethrin), in a 4 x 4 factorial combination. Tree height and groundline

diameter were taken at the beginning of the trial and annually thereafter. To date,

we have not observed any significant losses in tree growth although a slight reduction

in tree height was observed in the control and insecticide treatment plots, with the

disease expression being pronounced on trees in these plots. Tree phenology, spore

dispersal, disease incidence and severity, together with the environmental factors are

evaluated in monitoring plots which have been implemented for this purpose. The

disease symptoms which have been observed include those of deformed pinnules,

webbing of the pinnules caused by teliospores, leaf drop/ defoliation, stem cankers

and stem bending on taller trees. Across the 12 monitoring sites used for this study,

incidence of the disease was recorded with varying levels of severity. To date, no

disease related mortality has been observed, with only stunted growth having been

noted. These studies will contribute to our knowledge towards understanding the

impact and the biology of the pathogen to effectively come up with sound integrated

management strategies.


© ICFR 2017

Wattle rust breeding – current challenges (Is breeding for the wattle rust disease possible?)

Julian Moreno [email protected]



ABSTRACT

A new disease in black wattle, caused by a rust fungus (Uromycladium acaciae), emerged in the 2013/14 summer across KwaZulu-Natal and has extended across all the wattle growing regions. The disease affects plantations of all ages but damage seems to be greater at ages 0 – 2 years due to defoliation, which in turn affects initial growth and causes delays in canopy closure.

Following the major outbreak of wattle rust in 2014, the wattle breeding programme at the ICFR has focused on developing disease-tolerant genetic material, by identifying genetic variation and tolerance to the disease in the existing breeding populations. The aim is to produce seed sources of tolerant material for the wattle industry in the shortest possible time. Results of wattle rust assessments conducted in May 2014 in progeny trials established in the 2013/2014 season, indicated that resistance levels are very low and genetic control for this trait could not be determined. Tolerance, however, seems to be heritable and, at the family level, ranged from moderate to low, across trials.

Two new screening trials specifically designed to the disease (single-tree plots, 1.5 m x 1.5 m spacing and square layout), were established at Harden Heights and Bloemendal in the first quarter of 2015 and assessed for wattle rust in August-September. Despite lower disease levels in 2015 (relative to 2014), results confirmed previous trends:

• The lowest disease severity occurred in the more recently introduced and less improved material (Sherry seedlots, Australian provenances introduced in 1985 (Aus85) and first generation selections (SP4) from Aus85 families)

• The four more advanced genetic groups showed higher disease severity (SP1, SP2, SP5, SP6)

Of special interest was the performance of the controls, as follows:• As expected, the three A. decurrens seedlots were practically free from disease

• The A. mearnsii x A. decurrens hybrid seedlings showed average disease severity (only one site), suggesting no advantage of using hybrids

• Disease severity was similar between the four current PSOs and was above trial mean in one site (not good news)

• None of the PSOs showed particular susceptibility or tolerance to the disease (not surprising given their similar genetic origin)

At the family level, there was enough variation in disease severity across genetic groups, suggesting potential for breeding:

• Disease severity was indeed very low for a number of families from Sherry, Aus85 and SP4, confirming high tolerance levels in these genetic groups

• In groups SP1 and SP6, there were 19 and 3 families (in each of the sites) below the mean. This is good news, as this is the most highly improved material

• In contrast, only six families were below the mean (in one site) for groups SP2 and SP5

To conclude, it is important to keep monitoring disease levels in this trial series and confirm these trends at higher disease levels. In order to generate robust genetic parameters and breeding values, it is necessary to check for family ranking stability

(over successive assessments, sites and trial series).


© ICFR 2017

Measuring pitch canker in the nursery Andrew Morris

[email protected]



ABSTRACT

The pitch canker fungus (PCF), Fusarium circinatum, can be associated with post-

planting mortality of Pinus patula. A decade ago this disease was causing severe

economic losses in newly planted P. patula crops. An industry working group, funded

through FSA, was initiated in 2010 to address this problem. Post-planting survival today is

much improved as a result of applying research produced through this working group.

A critical understanding provided by the research was the link between asymptomatic

planting stock, infected in the nursery, and subsequent post-plant mortality. Armed

with this knowledge, a focus on nursery management interventions was possible.

The interventions that have proved useful in reducing asymptomatic infections are

improved hygiene measures.

Replacing P. patula with planting stock that is tolerant to PCF (i.e. P. patula x

P. tecunumanii hybrid rooted cuttings) has been another important industry response

to this disease. However, this planting option has less frost tolerance and so cannot

replace entirely the need for P. patula. Hence, continued production of P. patula

seedling that have low frequency of asymptomatic PCF infected seedlings is an

important requirement.

This presentation summarises current understanding of the infection mechanism and

presents the basic hygiene requirements to limit dispatch of asymptomatic infected

planting stock. Measures to recue contamination of planting stock via water, seed,

growing stock and re-used seedling trays are described. The importance of timeous

culling of symptomatic seedling in the nursery is emphasised.

The Pitch Canker Control Working Group is a good example of what can be achieved

through a collaborative industry effort. FSA are to be commended for their role in

supporting this initiative and are encouraged to support similar focused working

groups in future.


© ICFR 2017

Yield trends in Zululand – where are we going?Andrew Morris

[email protected]



ABSTRACT

The northern KwaZulu-Natal coastal plain has experienced a prolonged period of

below average rainfall now accentuated by the current El Nino driven drought gripping

southern Africa. Current crops are visibly stressed and yields being realised are less

than recent historical expectation.

This presentation considers the development of eucalypt forestry on the KwaZulu-Natal

coastal plain and the improved productivity this has delivered, together with the key

site characteristics that must ultimately determine production potential. Using inventory

records from more than 300 compartments (Mondi and Sappi combined) the growth

of crops planted from 2007 to 2011 is compared to the preceding crop. Spatial and

temporal rainfall patterns, soil type and the increasing number and variety of insect

herbivores are considered as factors influencing observed yield trends.

A key question facing forest managers in this region is the extent to which genetics

of their planting stock must change in response to fluctuation, and likely long term

change, in climate and soils if they are to ensure site resilience and sustainable wood

supply. This presentation is intended to inform this debate.


© ICFR 2017

Environmental triggers and impact assessment of a new rust disease caused by Uromycladium acaciae on

black wattle in South AfricaThobile Nxumalo*, Ilaria Germishuizen and Andrew Morris

*[email protected]


Presented at: IUFRO All Division 8 Conference: Forest environment under changing climates and societies, Beijing, China, 24-28 October

ABSTRACT

Black wattle (Acacia mearnsii) is an important plantation species in South Africa,

mainly because both the timber and bark are utilizable yield products. In 2012, a new

disease caused by Uromycladium acaciae, was identified in black wattle plantations.

This rust fungus previously occurred in South Africa with less disease expression, but

now posing a serious threat to the long-term economic sustainability of the crop. Little

is known about its biology, the reasons for this new disease manifestation and likely

yield losses. Therefore, a study was initiated to determine the impact of wattle rust on

growth and productivity and also; to understand the environmental triggers for the

disease outbreaks. Exclusion plot trials and monitoring plot trials were implemented

for the purpose of this study. Tree phenology, spore dispersal and disease incidence

and severity are assessed monthly together with climate variables. Disease symptoms

include deformed pinnules, webbing of the pinnules caused by teliospores, defoliation,

and multiple branching. To date, no tree deaths have been observed, but the

aforementioned symptoms have resulted in stunted growth. This study, which is still in

progress, will contribute to the knowledge required for the development of effective

integrated management and adaptation strategies in a changing environment.


© ICFR 2017

Detecting wattle rust (Uromycladium acaciae) using new generation Landsat 8 multispectral imagery and

advanced machine earning approachesMuhammad [email protected]



ABSTRACT

Monitoring and surveillance of forest pest and pathogens are essential parts of an

effective forest protection management strategy. However, current capabilities are

inadequate for the needs of the sector with conventional field-based methods being

prohibitively expensive, labour intensive and time consuming. During 2013, a new

disease was observed in black wattle around the Natal Midlands area, caused by a

rust fungus. The pathogen appears to be spreading fast and poses an enormous threat

to the wattle growers in the region. The aim of this study is to test the utility of Landsat

8 multispectral imagery to detect the presence of Uromycladium acaciae. Results

indicate that the partial least squares discriminant analysis (PLS-DA) model optimised

with 7 components produced an accuracy of 96%. Furthermore, the framework

successfully mapped the presence of the pathogen at different levels of severity,

and demonstrated the potential of multispectral information to accurately detect

the presence of wattle rust while developing an accurate monitoring framework.


© ICFR 2017

Unsupervised anomaly weed detection in riparian forest areas using hyperspectral data and lidar

Kabir [email protected]


Presented at: 8th Hyperspectral workshop on image and signal processing, UCLA, USA, 21-24 August

ABSTRACT

This study presents a novel unsupervised framework for mapping the invasive scrub,

Solanum mauritianum (bugweed), as anomalies within riparian zones of a forest

plantation using airborne AISA Eagle hyperspectral data (393 nm – 994 nm). Utilizing

an unsupervised random forest (RF) approach, the proximity matrix and Anselin local

Moran’s I anomaly detection reveal that the integration of LiDAR with minimum noise

fraction (MNF) data produce the best bugweed detection rate (DR) and false positive

rate (FPR). Overall, this research has shown the potential of combining hyperspectral

information with LiDAR derived height to precisely map (83%) the occurrence of

riparian bugweed using an automated unsupervised RF anomaly detection framework.


© ICFR 2017

Baboon damage surveillance: A remote sensing approach from space




ABSTRACT

The project aims at developing a surveillance system to monitor the extent of baboon

damage to forest plantations in Mpumalanga, in an attempt to quantify the economic

implications of such damage to the sector. Based on standardised field assessment

data supplied by forestry companies during 2014 and 2015, a consolidated map

showing the current baboon damage to plantation forests in Mpumalanga was

compiled. Using this data as ground verification information, satellite imagery was

acquired and tested for detecting baboon damage from a space-born satellite

platform, Landsat 8. Preliminary results indicate that the derived Normalised Difference

Vegetation Index (NDVI) was successful in detecting and mapping damage caused

by baboons and produced a first remote sensing based damage map with an

accuracy of up to 85%. The result is based on monthly field information combined for

2014 and 2015 while accuracies for individual months ranged between 57 and 70%.

Overall, the developed model provides an accurate framework for routine mapping

and monitoring of damage in Pinus compartments. Currently, the model is under

refinement whereby the potential use of synthetic aperture radar (SAR) is being tested.

In addition, the 2014/2015 results would be used as input data together with updated

field information to produce a 2016 remote sensing map for potential baboon damage.


© ICFR 2017

Spatial technologies for pests and pathogen monitoring and risk mapping



Presented at: Forest DST-FSIF Symposium, Pretoria, 18 October

ABSTRACT

The South African National Forest Protection Strategy clearly identifies the escalating

impact of pests and pathogens as a major threat to the competitiveness and

sustainability of the forestry sector in South Africa. Monitoring and surveillance of forest

pest and pathogen outbreaks, together with risk assessment of the potential impact

of existing and new forest pests and pathogens, are essential parts of an effective

forest protection management strategy.

New generation, moderate resolution space-borne imagery is an inexpensive, effective

technology for the mapping, monitoring and risk assessment of canopy pests and

pathogens. This technology has been widely adopted internationally for the monitoring

of forest health and in support of integrated pest management strategies. This project

aims to contribute to the development of a remote sensing based system for monitoring

forest health, and to generate capacity in the area of risk modelling and assessment of

existing and new forest pests and pathogens. The establishment of affordable pest and

pathogen monitoring and surveillance capability, and the development of skills in the

area of risk modelling and scenario development is mandatory for the sustainability of

the sector into the future, and is in line with the country’s vision of promoting the use of

earth observation satellites for the monitoring and management of natural resources.

The objectives of this project are:

1. To evaluate the potential utilisation of new generation moderate resolution

satellite imagery for mapping and monitoring pest and pathogens outbreaks in

plantation forests.

2. To develop ecological risk models with scenario capability for forest pests and

pathogens using geospatial and machine learning techniques.

Although the project focuses on a specific pathogen and pest; the wattle rust and the

Eucalypt gall wasp Leptocybe invasa, the technologies and capabilities developed

will be applicable to other pests and pathogens affecting the health of plantation

forests in South Africa.


© ICFR 2017

Mapping the eucalypt pulpwood supply chain: A brown paper exercise

Diana [email protected]



ABSTRACT

As a result of recent changes within the South African commercial forestry sector, the

supply chain is being critically examined for ways to reduce the cost of producing

timber and to optimise plantation operations. Improvements have been mainly

achieved by increased integration across the various components that constitute the

supply chain. However, to clearly identify challenges, solutions and the opportunities

key supply chain information is required. This includes customer product requirements,

identification of key players, activities and processes in the chain, any measurements

and the flow of information along the chain, logistics and any other external influences.

To develop this level of understanding, a brown paper exercise was undertaken

to map the eucalypt pulpwood supply chain. This was carried out with the cross

functional process owners and stakeholders involved in this project. The outcomes of

the brown paper mapping exercise is a holistic conceptual framework of the eucalypt

supply chain. The framework has captured the main drivers within the supply chain,

and incorporated the variety of management options and decisions that are utilised

in South Africa. The measures of success taken within the sub-components of the

supply chain were detailed, and issues and opportunities within and across the chain

highlighted. The potential of this process to assist the industry in attaining a more cost-

effective and efficient pulp wood supply chain is discussed.


© ICFR 2017

Multi-rotation management impact trials – insanity or progress?

The case of the Rattray trialDiana Rietz

[email protected]



ABSTRACT

There are concerns that the long-term productivity of forest plantations in South Africa

may be declining due to management practices. Evidence from literature shows that

in cases where plantation productivity has conclusively declined it has been due to

decreases in soil macroporosity, soil organic matter or site nutrients. The practices

most likely to decrease porosity include harvesting and site preparation practices that

involve machinery that result in significant soil compaction. Residue management

and the movement of machinery over the residues are most likely to affect the soil

organic matter and site nutrient content.

In order to investigate some of these effects, a trial was implemented at the Rattray

plantation in 1996 to determine the effects of mechanised harvesting practices,

residue management and initial fertiliser applications on long-term site productivity

of Eucalyptus grandis x camaldulensis. Treatments imposed were combinations of

different machinery (resulting in different levels of compaction and soil disturbance),

residue management and fertilisation.

In 2004, a new trial was implemented on this trial site that was specifically designed to

investigate the effect soil compaction (rather than specific mechanised operations)

and harvest residue management under Eucalyptus grandis. These treatments were

applied in a factorial manner to allow separation of single and combined treatment

effects. In 2012, the residue management treatments were re-implemented. This

presentation reports on the rotation end results of the second trial, early results from

the third rotation, and considers them in conjunction with the results from the first trial.


© ICFR 2017

Effective seed production systems for temperate eucalypt species

Tammy Swain*, Sthe Ndlovu, Robin Gardner, Sascha Beck-Pay, Adam Shuttleworth, Steve Johnson and Wayne Jones

*[email protected]


Presented at: Forestry DST-SIF Symposium, Pretoria, 18 October

ABSTRACT

The inability to produce sufficient seed from improved orchards of temperate eucalypts

is a barrier to deploying available genetic gain in the forestry sector, with temperate

eucalypts representing approximately 50% of the total Eucalyptus plantation area.

Research has shown that genotype, physiological age and hormonal status of the

plants, together with site (representing a range of environmental factors), affect the

reproductive phenology of temperate eucalypt species. Certain sites are associated

with earlier and more abundant flowering, but this could negatively impact pollinators.

Pollinators ensure genetic diversity and gene flow, in addition to successful seed

production, and a reduced abundance or activity of pollinators may result in poor

seed production, reduced outcrossing, inbreeding and genetic diversity of the resultant

seed. The latte three will influence the genetic quality of the seed being deployed.

This project aims to develop improved understanding in two areas of reproductive

biology and seed orchard management. The first is to understand the role that

different pollinators play over a range of temperate eucalypt seed production sites,

and whether opportunity exists to manipulate this to improve outcrossing and seed

production. Secondly, the aim is to assess the role that nutrients play in retaining seed

crops in temperate eucalypts.

Outcomes from this research will facilitate improved orchard management and

provide direction for future research. This has the potential to improve the genetic

quality and quantity of seed produced from temperate seed orchards in South

Africa, and allow the gains bred in tree improvement programmes to be realised

commercially.


© ICFR 2017

When is a eucalypt not Eucalyptus?Tammy Swain* and Gert van den Berg

*[email protected]



ABSTRACT

The sub-tropical region of South Africa is a high productivity area for eucalypt timber.

However, this productivity is being eroded by the advent of a variety of pests and

pathogens, as well as drought cycles in the region. As the single most effective means

of improving yield, reducing crop risk and obtaining more value from markets remains

the development and deployment of genetically improved planting stock, Corymbia

henryi was investigated as an alternative species for growth and improvement in

this region. Based on the performance of the species in ICFR site-species trials, a

1st generation breeding programme was implemented, and further elevated the

importance of C. henryi as a viable alternative for successful growth, particularly

on the drier sites of the region. In addition to good growth, stem form and pulping

properties, there is the risk of many pests and pathogens, to which Eucalyptus species

are susceptible, but which Corymbia species are not.

Such findings have prompted the development of an advanced generation breeding

strategy for C. henryi, focussing on continued improvement for a range of traits, and

increased seed production capacity. Predicted gains for the next generation range

from a 3.4 to 5.4 cm increase in diameter at breast height (23 to 49% respectively),

depending on site. Barriers preventing progress in the breeding programme, such as

vegetative propagation and seed production, are addressed to enable advancement

of the programme.


© ICFR 2017

Is fertiliser always needed when planting eucalypts?Louis Titshall

[email protected]



ABSTRACT

Despite the long history of fertiliser research in eucalypt plantations and the

development of broad generic fertiliser recommendations, there are a number of

concerns over the validity and usefulness of these across all growing areas. Site specific

responses are not always consistent, while key drivers of responses are not clearly

understood. In addition, as the recommendations are fixed there is no accounting

for changes in site quality due to inherent or anthropogenic factors. This study aims

address these issues by integrating the historical findings in a consolidated framework

and to investigate the direction, magnitude and drivers of the combined responses

to fertiliser application at planting using meta-analytics and multi-variate statistics.

The progress to-date on the data collation and capture and some preliminary data

analysis from the database that has been developed thus far are presented. Where

possible the original individual tree growth data has been electronically captured and

treatment means derived. Where the field raw tree level data cannot be sourced, any

summary data, records or reported results have been captured, though frequently

error estimates for means cannot be derived, limiting the value of these studies in

further statistical integration. Of the 138 eucalypt fertiliser studies identified, about 90

relate to fertiliser application at planting. However not all “fertiliser at planting” trials

have complete datasets with between 40 and 60% of the trials with meaningful data

for further analysis (depending on various decision criteria for inclusion such as age

class and fertiliser rate).

Preliminary growth responses using the highest and lowest rates of fertiliser tested in

the trials suggest that there is generally a small average positive response to fertiliser

application. However, high variability in many studies does not allow for site-specific

responses to be identified. Further data interrogation will require various treatment

and site-specific groupings to be identified with sub-analyses of these to improve the

value of the analysis. This aspect of the research is ongoing.


© ICFR 2017

The value of multi-rotation trials: An example with wattle

Louis [email protected]



ABSTRACT

The relatively slow crop cycle of commercial plantations compared to other annual

crops often means that any changes that can affect production potential remain

undetected as they are either small or masked by improvements in management.

Concerns over long-term changes in site productivity and quality are driven by issues

such as climate change, pest and disease and loss of soil quality. The vast majority

of South African forest plantations are now in their second or subsequent rotation.

Despite this there is very little conclusive information on the effects of multiple rotation

forestry on long-term site productivity (LTSP) of South African commercial forestry

plantations. In addition there a few true multi-rotation studies with long-term datasets

to examine these changes.

Arguably the oldest continuously monitored commercial forestry trial in South Africa

is the long-term wattle fertiliser trial at Bloemendal. Originally established in 1952 as

a factorial fertiliser and lime trial to develop fertiliser recommendations for wattle

production, the trial has been re-established a further six times and is currently in its

seventh crop cycle. This trial provides an opportunity to investigate nearly 65 years of

continuous forestry production on site productivity and quality.

This presentation discusses the value of multi-rotation trials in the context of site

sustainability understanding. The long-term wattle trial is used a case study that is

currently being examined in this context. The results of the recent crop cycle analysis

are presented and shown in relation to previous findings (where available).


© ICFR 2017

Understanding site water balance and nutrient supply resilience for use in improved water and nutrient supply

risk mapping for plantationsLouis Titshall* and Steven Dovey

*[email protected]



ABSTRACT

Production potential and drought risk associated with South African forest plantation

sites is dominated by water and nutrient supply. To predict potential productivity,

drought risk and nutrient supply potential at a forest compartment level, requires

knowledge of potential rooting depth and water/nutrient storage and supply capacity

of the regolith. Mapping at this scale is necessary if site-specific forestry practice is

to reap the full benefit available from practices such as site-species matching and

deployment of genetically superior planting stock.

Regolith is the unconsolidated layer overlying bedrock and consists of soil and

underlying saprolite/ saprock and colluvial and alluvial layers. The depth and degree

of weathering of regolith in South Africa varies considerably across the landscape,

however that tree roots extend into, and obtain water and nutrients from the deeper

regolith, is now recognised as an important component of water and nutrient supply

to forests. In South Africa several studies show this is important for forest plantations.

This project aims to characterise the regolith and its variation across a range of forestry

sites. The three key hypotheses to be tested are:

1. Regolith water and nutrient supply characteristics vary across the landscape in

an important manner for plantation production and management.

2. Stand productivity can be more accurately predicted by integrating regolith

water and nutrient supply characteristics into productivity modelling.

3. The variation in regolith characteristics occurs in a predictable and therefor

scalable manner for improved productivity estimation and management.

A key outcome will be to determine if regolith mapping can contribute to the

development of a more effective forest site classification system, through informing

site production potential, drought risk and nutrient supply resilience. This will enhance

the management of sites for improved plantation forestry productivity in South Africa.


© ICFR 2017

ICFR AUTHOR INDEXAckerman SA .......................................................................................................................................................................................14, 33, 34, 35, 36, 50

Bairu MW ........................................................................................................................................................................................................................4, 37

Beck-Pay SL ....................................................................................................................................................................................................4, 5, 38, 39, 65

Cele J .......................................................................................................................................................................................................................6, 40, 41

Croft P ...........................................................................................................................................................................................................................25, 42

Dovey SB ....................................................................................................................................................................................................7, 8, 9, 43, 44, 69

Gardner RAW ......................................................................................................................................................................................10, 15, 16, 38, 45, 65

Germishuizen I ........................................................................................................................................................................ 26, 27, 28, 29, 46, 47, 48, 58

Jugmohan M .....................................................................................................................................................................................................................51

Light ME ........................................................................................................................................................................................................................21, 53

Mbatha T ............................................................................................................................................................................................................................54

Moreno Chan J .................................................................................................................................................................................................................55

Morris AR ...........................................................................................................................................................................................................11, 56, 57, 58

Naidoo S .............................................................................................................................................................................................................3, 12, 16, 24

Nxumalo T ..............................................................................................................................................................................................................31, 54, 58

Peerbhay K ............................................................................................................................................................................. 18, 19, 20, 30, 47, 60, 61, 62

Rietz DN ........................................................................................................................................................................................................................63, 64

Swain TL ........................................................................................................................................................................................................6, 23, 52, 65, 66

Titshall LW .............................................................................................................................................................................................13, 17, 22, 67, 68, 69

Upfold SJ ..................................................................................................................................................................................................................3, 12, 32

A summary of research publications from the ICFR for 2016 01... · Institute for Commercial...

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