RESTORATION OF DEVASTATED VIETNAM VOLUME II: -FIGURES ...

R E S T O R A T I O N O F D E V A S T A T E D

I N L A N D F O R E S T S I N S O U T H -

V I E T N A M

VOLUME I I : -FIGURES, TABLES, and MAPS

- APPENDICES

C.F.W.M. von Meyenfeldt

D. Noordam

H.J .F . Savenije

E.B. Schel tens

K. van de r Torren

P.A. Visser

W.B. de Voogd

Cover : Aer ia l view of a bomb c r a t e r f i e l d in an inland f o re s t in Bien Hoa Province, South Vietnam, taken on 8 August 1971. P i c t u r e : Arthur H. Westing (Hampshire Col lege) .

W A G E N I N G E N - 1 9 7 8

VOLUME I I

Contents Page

FIGURES, TABLES, and MAPS

Chapter I I I 1 - 35

Chapter IV 36 - 52

Chapter V 5 3 - 5 5

Chapter VI 56 _ 73

Appendix I : BAMBOO SILVICULTURE 1.1 - I . 17

Appendix I I : CONTROL OP IMPERATA SPP. I I . 1 - I I . 6

Appendix I l l s EROSION CONTROL I I I . 1 - I I I . 1 1

•«//•//Zw. f MAP.Ill 1. South Vietnam, relief. ^ ^ Z U I D - C H I N E S E

Z E E

T H A I L A N D

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C A M B O DJhA 3 ^ 1

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Sca le 1 : 7,140,OCO

O O Lf

M A I L A N D

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Re l i e f

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200-500 m

500-1000 m

> 1000 m

VF UT 2 . Area d i v i s i on*

Kekonç Delta '1.Central Delta >2, Plain or ftaeds >3.Veittm Dalta id.Coastal areaa

Highland of the Mekong '1.ancient rirmr for-natione )2.Tableland of Binh-Phuoo )3.Recent riTtr foroations 34-Tableland of Xuan Loo >5.Dong Kai Delta >6. Coastal area

Central Coastel Plains M.Tri-Thien Plain 32.»*»-l*gai-Dinh Plain )3 .Plain of Phu-Yen ?4.Plaice o f Khanh-Hoa ^5.Plaine of Winh-Tnuan and Binh-Thuan

Central Highlands }1.Tableland of Kon Pion« :>2.Highland of P l e i Ku n.Dak Bla Plain ^ .Table land of An Kb« 05,Tableland armar ia* C6.Cheo Beo Valley 07.Tableland of **I>rak 08.Lao Thien Plain (.'^•Highland of Qu&ng-Duo 10»Tableland of Lao-Dong H.Highland« of Da Lat

Scale

50 50 100 tai

Phnom Pfmh

•9 - > •

MAP III 3. SOUTH VIETNAM,annualyearly precipitation (After: ROLLET, 1952).

Scale 1 1 8,010,COC

TABLS III 1. Some climatological data of South Vietnam (After: NUTTONSCN,1°63a)

A_ . Saigon Ha Tien

Altitude

m

8 3

T

°C

26,9 27,8

Tmax

°C

32,2 29,9

Tmin

°C

23,3 23,7

Tabs max

°C

40,0

Tabs min

°C

13,8

P

mm

1985 1977

Pabs max

mm

2718 2929

Pabs min

mm

1455 1070

P24 max

mm

178 234

Number o days wit: rain

days

153 120

B, Gia Ray 138 26,3 2146

Quang Tri Hué Da Nang Quang Ngai Qui Nonh Nha Trong Phan Rang Phan Tiet Vûng Tâu

DDalat Djiring Han Ba Ban Met Huot Plei Ku Kon Tum Blao

7 35 • 7 6

36 6

180 6

77

1500 972

1485 461 781 536 850

25,3 25,2 25,5 26,4 26,6 26,4 25,7 26,6 25,8

15,1 21,5 17,4 24,6 21,7 24,0 21,7

28,9 29,3 29,9 30,5 30,0 30,5 28,4 31,1 29,5

24,5 26,4 19,6 29,4 26,9 29,4

21,6 21,9 22,5 22,2 23,9 23,1 23,0 22,8 23,2

13,4 16,8 15,1 20,1 17,6 18,3

40,0 40,0 40,5 41,1 42,2 39,4 36,1 37,8 38,3

31,6 32,8 27,2 39,4 -

40,0

9,4 8,9

11,1 13,3 15,0 14,4 12,8 12,2 15,0

-0,6 5,0 6,6 4,4

3,9

2539 3304 2078 2215 1688 1450 760

1216 1296

1815 2059 3749 1899 2549 1861 2881

3813 4269 3071 3505 3081 2245 1186 1582 1877

2210 2509 5233 2326 3155 2693

1671 1880 1501 960 856 739 409 892 704

1019 1651 2484 749

2085 1514

353 -

333 485 391 259

-178 157

307' 452

-142 160 171

148 142 146 124 109 114 74 92

140

170 166 255 139 153 130

T = mean yearly temperature

Tmax = mean maximum temperature

Tmin = mean minimum temperature

Tabs = absolute maximum temperature max

Tabs = absolute minimum temperature min

p = mean yearly precipitation

Pabs = absolute max. yearly precipitati< max

Pabs = absolute min. yearly preoipitati< min _

P24 = maximum precipitation within 24 max ~T

houn

FIG. Ill 1. Climatic diagrams after WALTER,

— Cf_k3Sl SAIGON!««) .2E.31S35 HA-TIEN(Jm)

gA—I i*~W0

Explanat

F *\— • V ->i

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ion of the symbols:

„ . — .GIARAyCBrr,) ^ ' , 9 ^ 4.. ' ;••-«»

2^-5

a Station

b Altitude •

o Number of years of observation

d M«an annual temperature

e Mean annual precipitation

f Curve of the mean monthly temperature j. Dry season

1 scale part» 10 °C « 20 mm precipitation

g Curve of the mean monthly precipitation

h Rainy season

i Mean monthly precipitation of over 100 mm (reduced to a tenth of the scale)

I j y ' 2 5 3 9

26/1*2215 QUI-NH0N(6m| 2G.6"l68

(16) NHATRAN0l6m) 26.

FIG. I l l 1.("Continued)

PHANTHETB.-n) 26Ji°l2* 137) ~

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HAP III 4. Climatic types of South Vietnam (After: SCHMID, 1974)«

• CLIMATS SEMI-ARIDES ET CHAUDS

CLIMATS SEMI-HUMIDES ET CHAUDS

CLIMATS HUMIDES ET CHAUDS

CLIMATS SEMI-HUMIDES SUBMONTAGNARDS

CLIMATS HUMIDES SUBMONTAGNARDS

CLIMATS MONTAGNARDS

Area s t u d i e d by SCHMID

50 0 go 100 km ' '

9

TABLE III 3. The climatic types of South Vietnam according to the systems of (1).Koppen-(2).Schmidt and Ferguson-(3)«Schmid. Determined with the aid of the available data of some stations.

Station (1). (2). (3).

Saigon Ha Tien

Gia Ray

'Quang Tri Hul Da Nang Quang Ngai Qui Nonh Nha Trang Phan Rang Phan Tiet Vung Tau

'üalat Dj irrinx Hon Ba Ban Met Huot Plei Ku Kon Tum Blao

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Aw

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MAP I I I 5» Vege ta t ion types »

LEGEND

E

sa m B

a «oist evecgteen forest

» m o n t semi-deciduous fot«»t dry deciduous forest

" forest at high altitude

« ricefielda + plantations

=>batnboo-vegetation

''.'/y Scale 1 : 7.14C.OCO

i'H.

rtN

i»v

II°N

j V

18 Climats semi-humides et chauds. Basait 0-600 m. Deep well-drained soils, with good physical properties.

Climax:

Moist semi- -deciduous forest

Clearing

and

burning

gap

savanne-hallier * with Imperata, Poly-tooa, Phyllanthus and Aporosa.

A.1.1.

Moist forest with Lagerstroemia, Tetramelis. Undergrowth: hallier with Euphorbiaceae. Lianes (Apocynaceae, Annonaceae) abundant.

Secondary forest (forêt secondaire), next to species as Trema, Mallotus, Cratoxylon also Lagerstroemia angu8tifolia present.

-^Hallier with Euphorbiaceae (Aporosa, Mallotus, Maoarangi Ulmaceae (Trema), Hypericacea (Cratoxylon). Tilliaceae (Grewia), Moraceae (Broussonetia), Annonaceae (Polyalthi Often supported by felling, species regenerate. Bamboo species may occur, especially on slopes

Thicket with Eupatorium odoratum

Î -1 Colonization with Compositae, Gramineae.

I burning

— savannah with Imperata, Careya, Albizia en Phyllanthus

I burning

savannah with Imperata, Pteridium.

I burning

savannah with Themeda, Odina, Careya.

J, burning

savannah with Themeda, Schizachyrium, Odina.

I burning

savannah or p r a i r i e - s t e ppe with Arundinella, Aristida, Melastoma, Desmodium, Crotalaria, Dilleniaaeae.

Scheme I I I . l .

19 •

Climats serai-humides et chauds. Basait 0-600 m.

Adverse soils: shallow, plinthite banks or concretions, or poor water supply.

A.2.1.

Climax: Dry deciduous Leguminosae (Pteroearpue epp. ), Toona, Terminalia, Lagei*-forest with: etroemia.

burning

1 ret

1 -Secondary forest (forêt secondaire) with Lagerstroemia ccngusi folia.

Clearing Hallier with Lageretroemia, Euphorbiaceae (Maearanga, , Excoecaria, Mallotus), teguminosae (Dalbergia).

. T Savannah with Gramineae (Cymbopogon, Rottboellia, Amphtlophis Themeda triandra).

Î Colonizat ion with Compositae (Eupatorium, Blumea, Vernonia).

' Gramineae, Labiatae (.Hyptie).

Scheme I I I . 2 .

20

Climats semi-humides et chauds, Schist. 0-600 m Acrisols: easily erodable, sealing soils.

A.3.1.

Peni- or pseudoclimax (VIDAL): Dry deciduous forest.

-Forêt_semi;dense with Lagerstroemia angustifolxa, Xylva dolabriformus, Sindora sp Parînârîum sp., Irvingia sp; bamboo in undergrowth, (locally on less accidented sites in Darlac without bamboo).

Bamboo vegetation with Bambusa ep., Oxythenanthera sp,

Periodical felling and burning Woodland?

Pure bamboo vegetation, of the canopy.

after disappearance

-Bamboo vegetation with Bambuea sp., Oxythenanthera sp., Lagerstroemia angustifolia. Hallier with Cratoxylon ep., Lagerstroemia angustifoli

Bananeraie (.Musa epp.).

Thicket with Eupatoriim, Be lie teres, Malvaceae.

Clearing and _ burning

_Exploitation and burning

Scheme III.3

2t Climats semi-humides et chauds. 0-600 m. Shallow soils, adverse physical properties, basalt, schist, schist-sandstone.

A.1.1.

Pseudoclimax:

Woodland with Pentaam siamenois, terminalia tomentoea, Shorea obtusa. 1 " I

burning Exploitation

savannah -(on open spots, causing erosion)

Maintenance of woodland

burning

savannah (permanent)

Climax: Dry deciduous forest or moist serai-deciduous forest.

Peniclimax: Deep sandy soils on old alluvial terraces. Woodland with IH-pteroaccrpus obtusifolius. \

î \

exploitation

-) thicket with Helioteres, Grextia, Labiatae, Malvaceae.

burning

savannah

burning

Maintenance of woodland.

Scheme III.4.

22 Climats humides submontagnards. Basait. 800-900 m

B.l.1.

I—Moist evergreen forest with Dipterocarpaceae, Fagaceae, Lauraceae, Eugenia, Sohima.

Clearing and burning

Somewhat -richer — soils

poor soils 1

hallier with Vacainium

burning

prairie-steppe with Ari8tiaa Cumingiana

Î Secondary forest with Fagaceae, Lauraceae, Eugenia, Sohima, Elaeooarpue.

Î Hallier with Lithooarpus, Abarema, Lauraceae; possibly-, also Eugenia, Cratoxylon, Memecylon and Limacia. |

clearing and burning

Thicket with Rubue, Evodia, Aralia, Ternstroeraia-ceae. On more degraded soils also Rhodomurtua, Helaatoma, Gleiahenia.

î Thicket with Eupatorium odoratum.

î Colonization with Gramineae, Compositae

-» (Elephantopua, Gynura)..

degraded soil

savannah with Imperata

burning

savannah without Imperata

burning

prairie-steppe with Avietida cumingiana or prairie-steppe with Kerriochloa, Chryeapogon and patches of ha l l ie r species (Myrthaceae, Aporoea)

burning I Woodland with Pinus merkuaii and Diptero-oarpua obtuaifoliua with a hallier or thicket as undergrowth.

T burning

Woodland with Pinus merkuaii and Diptero-oarpua obtuaifoliua very open undergrowth, prairie-steppe with Kerriochloa, Chryao-pogon.

Scheme III.5.

23 Climats Humides submontagnards, Schist. Acrisols

B.l.2.

-Moist evergreen forest with Salntonia, Podooarpue, Miahelià; below 600 m * also Dipterocarpaceae and Leguminosae.

Hallier with Barringtonia, Sterculia, Lithoaarpua and other species

Î Hallier with Maaaranga dentioulata and Bambuea ep. (Oxythenanthera ep.)

/

Bamboo vegetation, 20 years after clearing pure stand

| too short clearing rotation and

^ burning • 10 to 15'years after clearing/ Bambuea ep. (Oxythenanthera)^

Hallier with Maaaranga dentiaulata, Rhodomyrtue tomentoea. Occupying c. 70% of the site 5 to 7 years after clearing.

Colonization by Imperata oylindrioa and Metaetoma ep.

Î Strong degraded sites

clearing . and

Thicket with Eupatorium odoratum. Predominance of Eupatorium during 3 to 5 years. <f>

Colonization by Compositae, Gramineae and other species.

Less strong degraded sites

burning

Scheme III.6

24 Climats Humides submontagnards. Granite or daoite. 900-1200 m. Acrisols.

B.l.3.

Clearing and burning

Moist evergreen forest with Ropea, Podoaarpua, Illioium, Quercua, Caatanopaia

Î Woodland with Fagaceae , especially Quercus epp,

) Woodland with Fagaceae (Quercus 8pp.) and Pinna merkuaii (will be fixed by periodical burning)

Î Pinus merkuaii with hallier species and familiei as Fagaceae (Querents epp.), Lauraceae.

î Pinna merkuaii with thicket species as Gleichen Aporoea and Melaatoma.

Savannah with Neyraudia madagaecarienaie or a thicket with Gleiohenia and Melaatoma.

burning

Prairie steppe with Arun-inella birmanica

burning

Prairie steppe with Pinus merkuaii.

Scheme III.7.

25 Climats semi-humides submontagnards. Basait. 700-1200 m. Ferralsols.

C.l.1.


Moist evergreen forest with Fagaceae, Lauraceae,Eugenia, Sahimz.

Hallier with Ternstroemiaceae, Fagaceae, Lauraceae, Hyrtaceae, Cratoxylon, Guioa. f

Woodland with Pinue merkusii; undergrowth a hallier. 'S

relatively little degraded soils

Colonization by Compositae, Gramineae, Rubus ep.

burning

Savannah with Imperata oylindrica

burning

Savannah with Arundinella setosa

burning

Prairie steppe with kristida ounringianfi

burning

Woodland with Pinus merkusii; undergrowth a prairie steppe.

Scheme III.8

26

Climats semi-humides submontagnards. Schist. Acrisols.

Cl.2.

Moist evergreen forest with Lauraceae, Fagaceae, Rhodoleya (Northern zone abov 800 m) or Lagerstroemia, Collona, Ornasia (Southern zone below 700 m).

* I clearing and burning on relatively rich soils clearing

and burning on poor soils

Thicket with Myrtaceae, . Melaetoma, Gleichenia. *

burning

Woodland with Pinne keaiya.

Hallier with Euphorbiaceae; later also Engethardtii Rhodoleya, Lauraceae and Fagaceae.


i Bamboo vegetation with BambuBa sp. and Oxy-thenanthera sp. sometimes together with hallier families as Euphorbiaceae, Malvaceae.


Scheme III.9.

27

Climats Montagnards. Granite or Daoite. Above 1200 m.

D.l.1.


Hoist evergreen forest with Fagaceae, Lauraceae, Aceraceae and oth families.

Soils developed from daoite:

Hallier of thicket with Fagaceaè, Ternstroemiaceae, Vacciniaceae form the climax on mountain ridges and very steep slopes.

Woodland with Vacciniaceae, Fagaceae, Hyrioa. on shallow soils.

Î ^Woodland with Pinue keaiya; undergrowth a hallier or a thicket with ferns, (peniclimax).

above 1500 m on relatively fertile soils

Prairie-- steppe with Quercus, lanata

-Savannah with Neyrandia, Miscanthus

burning I

Savannah with Arundinella, Pinue keaiya.

burning ' I

Prairie-steppe with Kerrioohloa, Eremochloa, Alloteropeia.

burning J

*Prairie-steppe with Pinna keaiya and Brainea ep.

Soils developed from granite: Moist evergreen forest with Gymnospermes : landslides favour the extension of Fokienia hodginaii and Pinua dalatenaie.

At higher positions of the mountains, on mountain ridges and tops a hallier with Fagaceae, Ternstroemiaceae, Vacciniaceae.

Scheme III.10.

The mountain formations are less stable than the lowland formations ; slopes are steep and soils are usually shallow, soil conditions are strongly variable. Landslides may occur on slopes with Acrisols (Argillic-horizon), even when a vegetation cover is present. When the forest disappears strong erosion may occur, especially when the soil is developed from granite, resulting in a irreversible situation. The climax formations in this zone have been less subject to shifting cultivation than those of other zones.

28 MAI- T U 6. The soils of South Vietnam (After: MOORMAN, 1961).

4

ndifferentiated alluvial soils. aline alluvial soils. cid alluvial soils. ery acid alluvial soils. rown alluvial soils of the riverlevees. egosols on recent marine sands. egosols on old marine sands. hallow regurs and latosols (generally shallow). 'on-calcic brown solis on acid rocks. fon-calcic brown soils on old alluvial deposits. andy podzolic soils on acid rocks. ed and yellow podzolic soils on acid rocks. ed and yellow podzolic soils on old alluvial deposits./ ray podzolic soils on old alluvial deposits. (<&} 11" .ow hutnic gley soils on old alluvial deposits. /_ î \ odzolic soils and regurs on old alluvial deposits. omplex of podzolic soil3 and alluvial soils on •espectively old and young alluvial deposits. Gompie* of mountaineous soils, mostly red and yellow odzolic soils and lithosolic soils. eddish brown latosols on basalt. ed and yellow latosols on basalt. larthy red latosols on basalt. hallow latosols on basalt. eddish brown latosols and red latosols on basalt. .eddish brown and compact brown latosols on basalt. 'eat and muck soils.

Scale 1 : 7,140,000

TABLE III S. 29

Soil units according bo MOORMAN (1°-61)

"Soil unitsTwïthïn Classification accor- Classification acco association or complex ding to FAO Soilmap of ang to Soil Taxono

the world, part IX 7th Approximation

1. Undifferentiated alluvial soils Sols alluviaux

eutric Gleysols

dystric Gleysols

Aquents Aquepts Fluvents

Saline alluvial soils Sols alluviaux salines

Halaquepts

saline eutric Fluvisols

3. Acid alluvial soils Sols alluviaux acides

thionic Fluvisols Sulfic Tropaquepts

•*. Very acid alluvial soils Sols alluviaux tris acides

thionic Fluvisols Sulfaquents Sulfaquepts

5. Brown alluvial soils of the riverlevees Sols alluviaux bruns des beiges

eutric Fluvisols Fluvents Dystrochrepts Eutrochrepts

6. Regosols

Regosols eutric regosols Psamments

Psamments

Regosols

Regosols

eutric Regosols Psamments

3. Shallow regurs and latosols generally shallow

Shallow regurs

Latosols

pellic vertisols

Nitosols/Ferrasols

vertic Eutropepts Chromudents Ultisols/Oxisols

). Non-calcic brown soils

chromic Luvisols Rhodustalfs (Xeralfs) (Haplustalfs)

). Non-calcic brown soils

chromic Luvisols Rhodustalfs (Haplustalfs) Durustalfs

.. Sandy podzolic soils Sols podzoliques sableux

weakly developed red and yellow podzolic soils Gray podzolic. soils (Locally)

orthic Acrisols

(ochric Acrisols)

Hapludults Ochrults

Ochrults

IBLK III 5. (continued)

'. Red and yellow podzolic soils Sols podzoliques rouges et jaunes

30 ferric Acrisols Hapludults

Haplohumults (lithic subgroups

Red and yellow podzolic soils ferric Acrisols

(Haplohumults) Hapludults

Gray podzolic soils Sols podzoliques grises

ferric Acrisols Hapludults Fragiudults Plinthudults Aquepts

Low humic gleysols gleyic Acrisols Tropaquults Tropohumults

Podzolic soils and regurs Sols podzoliques et regurs

Regurs Gray podzolic soils

pellic Vertisols orthic Acrisols

Red and yellow podzolic soils

ferric Acrisols

Pellusterts Haplustalfs Haplustults

Complex of podzolic soils and alluvial soils Complexe des sols podzoliques et des sols alluviaux

Red and yellow podzolic soils Gray podzolic soils

non-calcic brown soils alluvial soils

red and yellow podzolic soils

red and yellow podzolic soils t«-«w5l"tîo*N V"© gray podzolic soils latosols (not typical)

regosols '

ferric Acrisols

ferric Acrisols

ochric Acrisols orthic Luvisols

Gleysols/Fluvisols

orthic Acrisols (ochric) Acrisols orthic Acrisols

ochric Acrisols

Nitosols/Ferralsols

dystric Regosols eutric Regosols

Haplohumults Hapludults Hapludults

Hapludults Hapludalfs

Aquepts/Aquents

Haplohumults Hapludults Hapludults

Hapludults

Oxisols

Orthents

Complex of moun-teneous soils mostly red and yellow podzolic soils and litho-solic soils

lithosols Lithosols lithic subgroup

Reddish brown latosols Latosols brun-rouge (terres rouges)

rhodic Ferralsols

Humox Ustox Orthox

Red and yellow latosols Latosols rouges et jaunes

Red latosols (-transi- rhodic Ferralsols tion between 19 a.nd 21) Orthox

Yellow latosols Ustox

Earthy red latosols Latosols brun-rouge (terreux)

acric Ferralsols (Acr)ustox

TABLE III 5. (continued)

22. Shallow latosols Latosols skele-tique

31

ferric Acrisols Eutropepts Hapludults

23. Reddish brown latosols and red latosols Latosols brun-rouge et latosols rouges

rhodic Ferrasols

Humox

Humox

24. Reddish brown lato-, sols and compact

brown latosols Latosols bruns compacts orthic Ferrasols

Humox

Humox

25. Peat and muck soils Sols tourbeux

dystric Histosols Histosols

TABLE III 6. Land utilization in South Vietnam, 1960.

Area (1000 ha)

% of total area

Of cultivated area

1.Agricultural land a .Ricefields b.Arable land and market-gardens c.Perennial crops

2.Unused cult ivable land 3«Woods and forests 4.Savannah and natural grasslands 5.Remaining land

Total 17,167 100.0 Source: LANGLET (1973),after : Annual Agricultural S t a t i s t i c s , 196O-I961 a g r i

cultural Census 1960;Annual Reports of the Provincial Agricultural Services;McKinley,T.(l957).Forests of free Vietnam.

2,830 2,140

364 J26

4.9Ö9 5.027 2,370 1,343

16.5 12.5

2.1 1.9

29.1 32.8 13.9 7.7

10U 75.6 12.8 11.6

32 IM fil ,13 III 7» Area and production of principal crops, i960 and 1964.

Crop

Rice Rubber Coconut palm Bananas Fruit Sucar cane Sweet potatoes Ka~nioc Maize Groundnuts Kung beans Coffee Tea Tobacco

Area 11000 ha)

I960

2474,0. 72.8^(122.8) 42.3 ( 74.0) 58.1 53.2 47.8 42.4

4l.0 35.8 34.1

5.1I( 9.8) 6.8n( .8.3) 8.5

1964

2537,5 72.5 4i.6 18.1 34.O 34.O 48.0 43.0 37.0 35.0 20.0.

10.3

Production (1000 tons)

I960

4857.3 77.6 30.0

444.7 367.2

1527.6 237.4 254.6 37,4 32.5

•» 2.9 4.5 7.0

1964

5326,6 74.2 35.0

236.8 227.0

1061.4 301.O 28Ö.6

46.0 36.5 12.0 3.4 5.4 7.3

1*Mentioned are the areasin commercial production} total cultivated area in brackets.

- Unknown. Sources: 196O - LANOLET (1973), TEULIERES (1966)

1964 — KIT (1968), ANONYMUS (1965)

'.•ni.S III 8. Forest products of South Vietnam.

-a. Production in '

Product

SawEwood (mi) Firewood Cm ) Cnarcoal (tons) Eanboo (a ) Resins (hi) Terpentine (tons) Tannins and dyes Palm leaves (1000) Rattan (ar)

Sources: MAURAND (1

-b. Production per

1961 Timber („3) <

Charcoal (a ) Firewood (tons) Bamboo (m ) Resins (tons) Forest area (ha) % of the area

time.

Tear: 1939

400,000 470,000 63,600

247,000 5,000

63 700

37,000 18,300

943), FAO (1955),

region.

Mekong Delta, and land of the Mekor

278,164 810,254 104,910 62,791

622 1,268,114

22.5?«

-5

•

STAT.

High-

1954

300,000 440,000

14,250 18,000 2,000

224 20,000 kg 12,500

319 570 61

1260

,000 ,000 ,500

899 378

YEARBOOK OF FORESTRY (i960)«

Central Coastal Plains

23,213 78,509

589 2,899

147 1,976,250

35.1%

Central Highlands

41,145 19,950

106 1,111

18 2,382,700

~ss:.k%

Total Sout: Vietnam

342,522 .

908,713 105,605

• 66,801

787 5,627,064

100. 05s

Source: LANGLET (1973), after McKINLEY.T.W. (1957): Forests of free Vietnam, and

Annual Agricultural Statistics (1961).

MAP III 7. Administrative division and population density of South Vietnam (after: KIT,1968).

Regions:

South

can ton

provincial border PLEIKU province Pleiku chief town

o

Number of residente por k:n'-j 1= 0- 20

11= 20- 50 111= 50-200

IV= 200-400 V- 400-700

vi- 700-900

Scale 1: 9,000,000

34 TABLE III 10. The principal exnl

(after: MAURAND, 1

Species and class

Luxury wood Pterocarpus pedatus Dalbergia bariensis D. cochinchinensis Dysoxylon poureiri

1e Class wood Hopea odorata en H. dealbata Xylia dolabriformis Sindora cochinchinensis Shorea cochinchinensis Pahudia cochinchinensis Parashorea stellata Hopea pierrei

2e Class wood Dipterocarpus spp. Anisoptera cochinchinensis Lagerstroemia spp.

oited 943).

timber species

Exploited quant:

2.400 1.100

200 200

11.000 3.900 3.500 3.500 3.100 2.500 1.500

58.000 30.000 17.000

Of Viet

ity

nam in 1941

Indigenous name

Dang huong Cam lai Trac Huynh duong

Sao Cam xe Co mât Sen mu Go do Cho chi Kien kien

Dâu Vên vên Bang lang

7A3LE III 9. Exports and imports of agricultural products, 1961,

Product

Vegetable products LiTestock products Forestry products Fishery products

Total agriculture

Total Sapth Vietnam

Sxpoi Quantity (M.Tons)

251,347 9,937 1,404

633

264,9^7

•ts Valuo (1000 piaster*)

2,162,502 I42,b42

5,938 12,491

2,343,747

2,477,742

Source: Economic Information Newsletter, no. 63-2

Import Quantity (M.Tons)

152,039 22,272 44,44?

210,170

and '63-3»

s

Valuo (1000 piaster*)

1,066,145 453,885

28,991

1,553.1*8

8,928,317

*In i960 1C0 piaster valued about S 1.65«

35 MAP I I I 8 . Main communication network and communication cen t ren of South Vietnam

( a f t e r : STATISTISCHES BUKDESAMT WIESBADEN, 1972) .

\Vl«TiJ/M-

•="• Railways —— Important roads — Pass

"-•—"River •i Big harbour * Small harbour f Airport f* Airf ield

Scale 1: 8,700,000

3 6. IMORTH.

i VIETNAM

\~""' ^OUANG TBI CITY

V \ , >HJE »S.

MILITARY REGION I _ ,

AREAS SUBJECTED TO ECOLOGICAL WARFARE IN DECREASING DEGREE OF DAMAGE

FIT IV 1. Map of South Vietnam showing military zones and degree of destruction during the seoond Indochina War (after: VDiSTIBO, 1975).

Fin iv 6.

The ab»>ve is a composite of DOD maps showing where dilTcrent cloudsccding mi*-Mens were flown during Ihe 196*-1972 weather war in Soulhe:r' Asia. Accord-ing to the Pentagon, only selected sections of the above area were seeded during any one rainy season.

From SHAPLEY, 1971*.

37

Major battle areas

Free Fire Zones

Province boundaries

FIS IV 2. This map shows areas of major battles and also depicts

free fire zones in South Vietnam (after: WEISBERG, 1970).

38

As) O*W.A v CHINA

BURMA

IV 3 . . Craterization in Indochina (from;WEISBERG, 1970 ) .

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42

FIG IV 4 .

Herbicide Defoliation Missions—Fixed Wing 1965-1970. Data from HERB 01 file (From AHONTMUS, 197^«) .

"+

"+

44 TABLE IV 4- Southeast Asia cloud-seeding efforts.

The data were supplied by the Department of Defense.

Year Sorties flown Units expended

1967 1968 1969 1970 1971 1972

Totals

591 734 528 277 333 139

2,602

6,570 7,420 9,457 8,312

11,288. 4,362

47,409

After: SHAPLEY (1974)

TABLE IV 7. Effects of 'bulldozer operations on the basic infiltration of soils with different texture (afters VAM DE WEERT and LEN33LINK, 1972).

unaffeoted soils I bas mm/min

affected soils I bas mm/min

sandy loam loamy sand sand

12 17 29

0.04 1.7

16

TABLE IV 11. Production of forest products in South Vietnam in 1960, 1965, 1968 and 1970/71 (afters STATISTISCHE BUNDESAMT WIESBADEN, 1972.

:* ! Timber ( x1,C00 Firewood ( x1,C00 Charcoal ( x1,C00tons) Resins (tons) Terpentine(tons)

.960

319 570 61,5

899 378

1965

318 348

32,6 1101

593

1968

285 161

6,2 79 60

1970/1971

406 138

5,8 56

2

45

TABLE IV 5. Vegetation cleared-off by bombs (in 100ha). year by year for the land use categories (after: ODUM, 1974).

Land use

Land surface in %

City land

0.06$

Agricultural land

17.23$

Forest land

58.80$

Mangrove

1.60$

Rest

22.31$

Year

1965 1966 1967 1968 1969 1970

Total bombs

O.96X iof 1.5 x 10g 2.8 x 10° 4.3 x 10° 4.2 x 10° 2.9 x 10°

0.5 1.0 1.3 1.9 1.8 1.3

120 190 360 540 530 370

400 670

1,610 1,860 1,780 1,250

10 20 30 50 50 30

Totals 16.9 x 10° 7.8 2,110 7,170 190 2,630

Total: 1,219i100 ha

TABLE IV 6. The vegetation types of South Vietnam according the Committee on the effeots on herbicides and according chapter III.3 and, furthermore, the area occupied by eaoh vegetation type according to the Committee.

Vegetation types according the Committee on the effects of herbicides

Vegetation types as discribed in chapter III.3

Area of the vegetation type, in ha

1. Closed forest a. Dense forest

b. Secondary forest with bamboo and shifting cultivation

2. Open forest a. Leguminosae and

Lagerstroemia forest

b. Dipterocarp forest c. Pine forest

Closed forest formations Moist evergreen forest, Moist semi-deciduouB forest, Dry deciduous forest, Formations at high altitude Thicket, Hallier, Bamboo forest

Woodland Forêts semi denoe (intermediate between dense forest and woodland) Woodland up to 600 m a.s.1. Woodland from 600 m a.s.1. and up

3 . 4. 5-

6. 7. 8.

9.

Mangrove Melaleuca woodland Barrenlands a. Sand dunes b. Brachland Savannah Grassland Grass and sedge

Cultivated land

swamps

Mangrove Melaleuca woodlands

Casuarina woodland Thicket in CSAC Savannah Prairie-steppe Grassland, Swamp forest, Riparian forest Cultivated land

TOTAL

3,080,000

6,ioo,oco

400,000

810,000 180,000

290,000 190,000

810,000 8c0,000 230,00c 73c, 000

3,180,coo 16,bXl,CC0

46 FIT IV 7. The nutrient cycle between Boil and forest fallow

(after:NYE and GREENLAND, 1960).

Nitrogen fixation

symbiotic

Denitrification

non-symbiotic

Rain and dust

Vegetation store

Plant uptake

Litter fall and

rain wash

Litter store

Mineralization

Soil store

Run-off and erosion

Drainage

FIG IV 8. Effect »f compaction on pore size distribution (after: VAN DER. WEERT and LENSELINK, 1972).

L v. •» total soit

oquirotont port 4 > HO fil'

JOA/ < fci/i¥0lrnt port f < JêOjU

« H -

tounoltnl por» 0 *}0M

A

V. at total toil v o turnt

tquivottnt port t> >I90^

20M <tijui*oitnt port 0 < l&O/tt

US '40 MS ISO ;.55 16C MS !?0 !?5 1 iZ HO US ISO TS5 160 I « l?Q f 75 110 bv'.k étnt-rj bulk dtniity

A. Compressed at water content of 16.6% by weight ( = pF 2.0) B. Compressed at water content of 31.5% by weight ( = pF 0.4)

(points arc averages of 4 cores)

47

FIQ IV 9. Changes in sediment load of the Javan Citarura river as a result of erosion in the catchment area (from: KLOOTWIJK, 1975, after: SOEMAHHOTO, 1974l The soilerosion problem in Java. International Ecological Congress, The Hague, Holland, 1974, p36l-364).

silt content

month

FIG IV 10. Ratio of water flow of the Citarum river in the wet and dry season (W/D)(after: see FIG IV 9.).

10

O

cc

1920 "sÏSwö-WO

YE/»R

48 TABLE IV 6. Cultivated area and production of the most important agricultural

crops in South Vietnam, 1966, 1970 and 1973.

CROP

Rice Maize Sorghum Sweet potatoes Manio c Co co nut Bananas Pineapple Sugar cane Groundnuts Mung beans Soya beans Rubber Coffee Tea Tobacco Jute

CULTIVATED AREA (x1,000ha) 1266 1210 197J

2294.8 29.2

39. 39. 39-

59-

30. 30, 20, 6.

56.7° 10.2' 8.2C

7.2

2516.7 28.6

1 33 30 32.2 20 4.5

12 30.2 17 6.8

39.2v 9-Al 8.2C

8.5 0.3

2830 40 12 40 48

26

17 39

11

8. 7.

11. .4 ,6

0.1

PRODUCTION (x1,000tons) 1966 1970 1973

4336, 35.

246.2 290.3 113.9

] 417.8

935.7 34.4 14.4 7.6

49-5 3.1 5-2 6.9

5715.5 31.4 2

220 216 104.2 204

33 336 32.2 11.1 7.5

33.0 3.9 5-5 8.4 0.3

7025 51 13

279 280 110 258 34

530 45

11 40

5-6.

10. 0.

a: mentioned are the exploited areas of rubber} totally planted areas were: in 1966 126,340ha and in 1970 105,800ha

b: Totally planted areas of Coffee and Tea; exploited areas unknown.

SburceurFAO production yearbook, 1972 and 1974, FDD (1974), KIT (1968).

TABLE IV 9. Index figures of agricultural production and population in South Vietnam (1961-1965 : 100).

A: Population index B: Pood production C: Agricultural production D: Pood production per capita E: Agricultural production per capita

A B C D E

1963

100 102 102 102 102

1964

103 104 103 101 101

1965

105 100 99 95 94

1966

108 93 92 86 85

1967

110 98 96 89 87

1968

112 94 92 84 81

1969

115 105 101 91 88

1970

117 114 110 97 94

1971

120 122 119 102 100

1972

122 123 119 101 98

1973

124 134 130 108 104

1974

127 139 134 109 105

Source: FA0 production yearbook, no. 28a, 1974

TfrBLB IV 10. Live-stock in South Vietnam, 1960, 1965, 1968, 1970 and 1973 (number of animals x 1,000).

1960 1965 1968 1970 1973

Horned cattle Buffalo PiS Chicken DuckE

Sources: FAO pi

1,078 754

3,620 16,700 9,900

poQuction ye

1,101 733

3,473 22,200 13,500

arbook, 197

953 647

3,553 20,000 14,100

930 620

4,087 22,100 16,300

853 501

4,275 24,500 18,400

4 J STATISTISCHE BUNDESAMT WIES

49

FIG IV 11. Cultivated area of rice and the rice production in South Vietnam, 1961-1973 (after: PAO, 1972 and FAO, 1973).

Area

iA

V

**

l,3j

u

V--

Production

(f/0<7ó«)

Ay

>,o

Ç6

a

4.8 2,v

^

-* ! ' c" H n» - I i i

3<wn: '96' S Êr fy éj 7 ' 'T3

Production (K lo'T9K)

Area . { (x ••' k«.)

SI

TABLE IV 12. Summary of settlements in the 18 study areas that may t have heen exposed to the reported herhicide misions (after: THOMAS, 1274). _.._._

Study A » ,

Total Nuabar of Sattlananta

Nuabar of Sattlananta Xrrtngad According to tha Dunbar of Tim«« that tha Cantarlina of

a Raportad Harbicida Miaalon Paaaad Mithin On» Klloaatar of their cantar«

0»notSprayad Sprayad Sprayad Sprayad

Sattlananta Sprayad a a Pareant of Total

Huabar in Study Ara» apravad 1 tliaa 2 t l aaa 3 t lnaa 4 or aora t iaaa gattlamanta

Manyrova

1 1 3 4

Oaltt

S 6 7

Plantation

3 10

30 104 56 25

67 119 103

62 13

140

Loxland Vallav

11 13. 13 14

6 38

108 11

9 43 5 3

34 57 26

6 18

122

0 0

36 0

Uplaad Vallav

15 17

Swldaan

16 17 1«

S3 69 37

2 15 4 2

12 12

5 4

10

0 0

13 0

1 .

•/ 6 2

6 21 19

0 0

IS 0

1 20 10

12 2 2

IS 29 36 13

IS 9

35

34 4 3

S 38 34 11

31 45 36

83.3 S9.6 91.1 88.0

49.3 52.1 74.5

90.3 43.8 12.9

100 100 64.8

100

96.2 88.4

100

TABLE IV 13. Exports and imports of grains in South Vietnam ( SV) during the years 1960-1963 ( xl.000 tons).

Year

1960 1961 1962 1963 1964 1965 1966 1967 1968 1969

Balance of rice (imp.=-jexp.=+)

Exports from USA toward SV rice maize wheaten flour

+ 340 + 154 + 83 + 322 + 48 - 129 - 434 - 750 - 677 - 341

13 2

47 -1

186 349 670 524

---

41 67 29 37 22 37

50 60 77 37 69 83

135 75

127

Sources: Vietnam-Bulletin, 10-1 » 1975 » ANONYMUS, 1969.

TABLE IV 14. Expired!

Production in SV rice maize

4,955 4,607 5j205 5,327 5,185 4,822 4,336 4,688 4,400

27 32 38 37 46 44 35 34 33

52 TABLÏ IV 15. Tree species introduced and/or planted in Vietnam

(after: various authors).

Acrocarpus fraxinifolium Aglaia gigantea Alstonia Scolaris Bassia pasquieri Bischofia javanica Callistris glauca C. obtusa C. robusta Cassia siamea Casuarina equisetifolia Chukrassia tabularis Cunninghamia sinensis Cupressus macrocarpa C. sempervirens C. torulosa Dalbergia bariensis D. cochinchinensis Dipterocarpus alatus Erythrophleum fordii Eucalyptus alba E. algériensis E. camaldulensis E. cineria E. citriodora E. globulus E. gomphorephala E. longifolia E. maidenis E. microcorys E. microthera E. punctata E. resinifera E. robusta E. rostrata E. rudis E. saligna E. teriticornis E. viminalis Hopea dealbata H. odorata Khaya senegalensis

Lagerstroemia flos-reginae Leuceana glauca Liquidambar formosana Manglietia fordiana M. glauca Melaleuca leucodendron Melia spp. Hesua ferrea Pahudia cochinchinensis Parinarium annamense Peltophorum ferrugineum Pinus caribeae P. echinata P. elliottii P. halepensis P. kesiya P. longifolia P. massonia P. merkusii P. patula P. pinaster P. radiata P. rudis P. sinensis P. taiwannensis p. tenuifolia P. thumbergii Pterocarpus pedatus Sequoia sempervirens Shorea cochinchinensis Sindora cochinchinensis S. tonkinensis Spondias tonkinensis Styrax tonkinensis Swietenia macrophylla Talauma gioi Taxodium distichum Tectona grandis Toona febrifuga Vatica tonkinensis Xylia dolabriformis .

TABLE IV 1f. Area needing reforestation, in 1,000ha, by vegetation zones in the three climatic-geographic zones of South Vietnam (after: SNANSON, 1975).

Vegetation zone Bare hills, brush Grass fields Sand dunes Swamps, Mangrove sites

Central lowlands

680 17 9? -

Central highlands

370 114 --

Southern Vietnam

18 -

16 700

Total

1,068 131 108 700

Totals ~W) 4BT 734 2,007

53

FIG V 1. Schematic representation of activities in land evaluation (after: FAO, 1976).

KINDS OF LAND USE

Major kinds of land use or land utilization types

\ LAND USE

REQUIREMENTS AND

LIMITATIONS

0—es

INITIAL CONSULTATIONS

- Objectives ' - Data and

assumptions - Planning of the

evaluation

•—-___ITERJ TION___

COMPARISON ,OF LAND USE WITH LAND

- Matching - Economic and

social analysis - Environmental

impact

A LAND

SUITABILITY CLASSIFICATION

A PRESENTATION

OF RESULTS

LAND

MAPPING

UNITS

J LAND

QUALITIES

e o u o

6

•m o

l

J3 o.

o

o

ti n

t 3

n > o •H •f» a •H D.

« >>

3 ° Ol -H

60 O

:> >» •a b tD O p . o

6H

54

o to

E •rl

ü

O +» O I«

Maintain forest reserves

Seeundary growth

Natural vegetation

Shape of the slope

Length of the slope

Gradient

Physical soil properties

Chemical soil properties

Temperature

Intensity of rainfall

Distribution of rainfall

Total rainfall

G

o o o o o o o o c y

O O O O « - « - T - « - C \ J

O t - r O W N i - r W

O * - t - t - < M 0 J i - C M C \ l

o o o o o o o « - o

o o o o o o o e u o

W r - . - ^ i - . - r - N O

f W r r N O O O O

0 0 « - » - O O T - 0 0

O O O O O O O C M O

O r r r O O » - « 0

pn

•a a rt rH

•Ö

» <H ci

a -H E «) « fc +» n C >> o ta

a s o O -H •H +» +> 0)

rt > • -H •H +» 4* »H rH 3

g° +> « B

O » •H a u «s «.E o o s o«

es e 0)

• f a

n E

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>> t l I-H rH u •d s d

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O 3 P o o

1-4 H

a P K » (0 0 h •3

+• a a ot V u a O .M

O Vi h h «J P C P .

+> O O) ttO > rH -H r-l

•H Q H a -n -n C f a » Cl 'H h -H fi

o. (n -s:

P +» CO S O B 'r i O O > -f -ri

r-l O 4» •H r. I\J CO CU 5 5

I I I I I I

o d lu

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o • H C

o c » i-i

9 O D a 3 &

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e

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a o a.

a h O

-f» O

.?

55 Political stability

Service organization

Research organization

Forest service

Marketing- organisation

Credit organization -

Information organization

Management organization

Silvàoultural know-how

Agricultural know-how

General level of knowledge, alphabetism, level of training

Level of mechanization

Marketing possibilities

Working up possibilities in the nearby surroundings

Size of the cultivated areas

Level of opening up

Yield

Settlement pattern

Labour supply

Mobility of the population

Population density and' Growth

^

<D

T —

O

*—

*~

t —

o

(M

-

(M

O

O

O

O

•

Tm

o

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CM

O .

CM

O • - CM CM CM O l CM

o o o o o o o

O O O i - »- o * -

O O O CM CM CM CM

r N O r r O O

»- C\J O t - o o o

O »- O »- CM CM CM

O O O CM CM CM r-

N N i - N O O O

O t- O o «- o o

«- CM O CM CM O O

o o o *- o o «- o o

O O f r O r> W O W

T- *- t - f- O CVI W O O

« ftl T - C J W ( \ | W O O

O O O O W W T - O O

T- , - O O J O C M C M O O

O O O O T - T - T - O O

CM CM T» f WW T- i- w

CQ CS

C O O r t

•H4»

+• a nj f

a e o

o c +>

* *$a +» P. «

VS « e

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e V at 3t ft. t<

a o +» +» . P l Ü H H •

a -H a IH s |H C H -H O a c 4» » -H to e <M -H > Il M H f, H h o x ) So -H es a. m ^ to

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O (4 Cl

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«1 o o +> Tl

£i I l I I I I I I I

56

From WYATT-SMITH, 1963.

57

KKÏ v i 2 -fltll dipierocarp forest in Bukit Lagnng Forest Reserve. Sclangor. 1000 ft. a.s.l. These are lowland dipierocarp forests found above 1000ft. on the inland hills. The profile illustrates the most common type, the se raya iShorea curtisii) t>pe. found along the broad ridges. Here the structure may be taller than the optimum truly lowland types. Note the presence of the stemlcss palm. Luncissona triste, which in characteristic.

1 - Lophopctafttm reflexion 2-Shorca curtisii 3-=A7iorrn bractcofata 4 — Calo-phyUum iftophyHuiJe 5 -Ctcnolophon purvifotitis 6 -• Monoctirpia nuirginolis 7 — Shorca leprosula 8 - Xanihophytttim amoenum ^-PsciiJoeirjcnia sinçaporcn.sis \0-Mirisoph\Hcti eorneri M - XaiUhophylfum discolor 12 -Hydnocarpus wooJii iy — I)yera costittata \4~XylopUt fcrruginea \5 — Ryparosa kun.stlcri \6~Artocurpus nitidus stibsp. griffithii 1 7 " Xanthophyllum obscurant 18 - Eugenia yriffithii 19 -fllumeoiicnjron tokbroi 20 —Myr'tstica inert 2\~rCyuihociilyx carinutus 22' Strom-bosia javanica 2$~ Snntiria rubiiiino^a 24-A(juiluria imtlaeeensis 25 ~ A porosa sympiouosoiitcs 2b - Siemimurus timbcltotiis 27 — Rutntia scortcchinii.

From WYATT-SMITH, 1963.

58

TABL^ VI 1. Stocking of two types of virgin Malayan Rainforest (after MUR, 1964).

Red Meranti-Keruing type Seraya ( r idge) type

2 3 4 5 6 7 1 2 3 4 5 6

Spp Group A 10 15 3 0 .9 2 - - 8 20 3 2 .3 5 5 2.1

Spp Group B 37 112 20 19.0 52 30 14-4 15 50 9 13-9 27 15 11.8

Spp Croup C 10 15 3 1.1 3 3 0 .7 25 40 7 11.4 22 20 9 .9

Spp Group D 20 47 9 3 . 0 9 5- 1.4 23 33 6 1-4 3

Total A-D 77 190 35 24.O 66 38 16.5 71 143 25 29.O 57 40 23.8

Weed trees 22 35 6 1.6 4 - - 20 55 9 4.4 9 1C 3.6

Unclassified - 325 59 10.9 30 5 1.1 - 380 66 17.6 34 15 4.4

TOTAL

Dipterocarps

99 550 100 36.7 100 43 17.6 91 578 100 51.0 100

30 95 17 15.5 43 23 11.4 25 93 16 23.2 45

65

30

31.8

19.9

1: No. species over 10 cm d.tun./ha 5* Basal Area as % of total 2: No. steras/ha over 10 cm d.b.h. 6: No. of stems/ha over 47.5 cm d.b.h. 3: Stems over 10 cm d.b.h. as fo of 7: Basal Area per ha over 47«5 en d.b.h.

total 4: Basal Area (mVha) of stems over

10 cm d.b.h.

I Heavy Hardwood Species Group A

II Medium and Light Hardwood Species Preferred species Group B Desirable species Group C Acceptable species Group D

59

T^BLE VI 2 . 'Pour m o n o c y c l i c s y s t e m s w i t h t h e i r s i l v i c u l t u r a l t r e a t m e n t s a n d t h e p o i n t o f t i m e o f t h e s e t r e a t m e n t s ( a f t e r BAUP, 1 9 6 4 ) .

M.U.s. Maleis ië

T .S .S . Nigeria

T .S .S . Trinidad

Extended S Andamans

R o t a t i o n n-5 n-3 n-2 n - 1

1 2 3 4 5 6 9 10

70 (Ru) (C) (CC)

S,F,Ro,Ru

(L)

S,(CC,L,T,Ru)

S,(CC,L,T,Ru)

100 S.CC.Ru

CC.L.Ro

60

CC F,Ru*,Ro",(P)

L L CC.L CC.L.Ro

Ru ) )C.

) CC * F,Ru L,C,CC L,C,CC L,C,CC,Ro

CC BU C a

v Ko

L f P x ( )

Climber cutting. Undarstorey removal, cutting and poisoning of useless trees. Undergrowth clearing; elimination of shrubs, palms, or bamboos. Diagnostic sampling. By sampling data about composition, development and competing position of the regenerating stock are recorded. Information is used to determine further silvicultural treatments. Felling. Overstorey removal; poisening of useless trees in the upper strata, liberation. Thinning. Artificial regeneration; enrichment planting. Partial treatment. Treatment only in parts of the forest, or, depending on the results of the diagnostic sampling, treatment is or is not carried out. Year of exploitation.

60

TABLE VI 3 . R e su l t s of an L.S.M. survey i n a H i l l D i p t e r o c a r p F o r e s t . Compartment s i z e : 103.6 h a . Sampling p l o t s i z e : 1.4 h a . (Af te r HYATT-SMITH, 1963) . (A l l f i g u r e s are conver ted t o h a ) .

Vali'.able species classification n

Stoc

xun-ber

Shorea laevia Balanooarpua heimii Inteia bakeri Total group A %

Koompaeaia malacaeneie Dipterocarpua orinitus Shorea ovalia Shorea macroptera Shorea acuminata Shorea parvifolia Shorea 'leproaula Pentaoe spp. Shorea pauciflora GonoatyT.ua oonfuaue Shorea eurtiaii Total group B %

Durio spp. Artooarpua lanceifoliua Shorea braoteolata Aniaoptera soaphula Parkia apeaio8a Alstonia spp. Endoapermum malaccense Campnoaperma auriculata Total group C %

Calophyllum spp.

91 21 8

120 4.8

4 9

81 135 467 99

336 1

91 4

301 1528 61,1

2 2 1 1 6 1 1 1

15 0.6

4 Burseraceae (Canariim spp. Daoryodea spp. e.d.) Hopea becariana

29 2

Sapotaceae (Palaquium spp. Payena spp. e.a.) Total group p %

Total groups B-D

%

6 41

1.6

1584 63,4

kin/» of chosen

height h < 30 cm

39 9 4

52 43.4

4 8

72 132 434 91

323 1

54 4

287 1410 92.2

2 2 1 1 5 1 -1

13 86,7

3

18

-

4 25

59.6

1447 91.4

class 30

ceedlii

om<h <150 cm

52 12 4

68 56.7

0 1 9 3

33 6

13 -

37 -

14 118 7.7

----1 -1

-2

13.3

1

11 2

2 16

40.4

136 8.6

Igß

occurence numb.of plots with 1 seedl.

39 16 8

63 52.5

4 9

25 33

121 22 89 1

53 3

40 400

26.1

1 2 1 1 6 1 1 1

14 93.3

3

24 2

4 33

82,5

447 28.2

2-5 5

sec. seedl.

seedl. seedl.

27 2 -

29 24.1

0 0

31 44 •

174 31

116 -

24 1

70 493

32.2

1 -------1

6.6

1

4 -

1 6

15.8

500 31.6

25 3 -

28 23.3

--

25 59

172 45

131 -

14 -

191 637

41.6

_ ---------_

1 -

-1

1.7

638 40.3

number

_ ----

---9

32 5 6 -4 . -3

59

« ---------

_

--

--

http://GonoatyT.ua

61

TABLE VI 4 . E f f e c t s of l o s i n g and poisoning on Kapur Forest Type, Malaysia ( a f t e r BAUR, 1964) .

Number of stems > 10 cm d.t) .h ' .

No. / ha i>

Basal Area > 10 cm d . b . h .

m2/ha %

Removed in logging Broken in logging Standing after logging

Poison girdled Retained stems

Group A Group C Group D Unclassified

TOTAL before logging

25 138 525

138 388

38 25

113 213

688

4 20 76

20 56

5 4

16 31

100

6 .9 5.1

26.9 12.5 13.4

38.0

3.2 0 .4 3.7 6 . 0

1° 13 68

33 35

1CP

9 1

10 15

TABLK VI 5 . Expected growth i n areas o f t r ea ted r a in fore s t ( a f t e r BAUR, 1964) .

Natural Regeneration System

M.U.S. Maleisië

T.S.S. Nigeria

T.S.S. Trinidad

Puerto Rican Improvement cutting/Selection System

N.Queensland Improvement/ Selection System

Rotation felling

(year)

70

100

60

5-10

15-20

or cyole

Yield from initial exploitation

(m3/ha)

60

28

91

?

28

Annual increment of new crop

(m3/ha)

2.1-4.2

1.2

6.2

4.2

2.8

Hew crop yield

(m3/ha)

145-290

420

350

21-42

42-55

62

Appendix VI A. DIAGNOSTIC SAMPLINGS

The area to be sampled for a Linear Sampling Survey is divided into units not larger than 160 ha. A so-called base line is cut approximately along the contours of the land and parallel to the vegetation boundaries of each unit. At right angles to this line are cut the so-called sampling lines, each ending at the boundary of the unit to be sampled. A sampling "line", therefore, consists of a series of rectangular sampling plots. The distance between the sampling lines is

00 or 200 m. For the Milliacre Regeneration Sampling (L.S.M.), the sampling plots each cover 4 m . At every 100 m (intensity 2%) or every 400 m (J%) a sampling line is made, depending on the intensity of the sampling. Regeneration is sampled in every plot. The total number of stems/ha gives insufficient information for determining whether natural regeneration is significant. The regeneration of many species occurs spot-wise, mainly below mother trees. Therefore it is better to give the occupation percentage: the number of sampling plots occupied with at least one specimen of a valuable species compared to the total number of plots. A division in classes, as mentioned in table VI l,is used.From the most healthy and best developed seedlings (chosen seedling) the species is determined; further it is indicated approximately how many seedlings of this species are present in the plot. This is done for each class (A, B, C, and D). The height of the chosen seedlings should not exceed 150 cm. If the chosen seedling is a less valuable species, then (if possible) a secondary seedling is selected. If the chosen seedling is from class D, the secondary seedling must be from class B or C. Class C regeneration is only chosen if class B regeneration is lacking. A class A seedling can never become a secondary seedling. For the L.S.H., the eventual dominance of Eugeiseona triste, bamboo and other competing species is also noted. The information is summarized in tables and presented on a map, by which a review of the valuable regeneration can be obtained. The L.S.J is carried out according to the same principles as the L.S.M. However, only regeneration over 150 cm and below 10 cm d.b.h. is enumerated (except for class A regeneration, of„which smaller specimens are also enumerated). It is sampled in units of 25 m ; depending on the intensity, every 100 m (5%) or every 200 m (2.5%) a sample line is surveyed. A stocking of 50% (200 well-distributed samples/ha) can be accepted, although it must be coupled with a minimum overall stocking of 40% for class B and C species in the total number of plots. For the L.S.J, regeneration from 5 cm d.b.h. is enumerated. It is sampled in units of 100 m , the sampling lines are placed every 100 m (intensity 10%) or every 200 m (5%). A stocking of 60% (60 well-distributed samples/ha) is considered minimal, provided half of this stocking comprises class B or C species. Furthermore, notice is taken of the size class and position of each crown in the canopy of the chosen seedlings and secondary trees. Class A trees are enumerated separately. If the stocking is adequate, the regeneration phase is considered to be finished. Finally, there is the L.S.R. (Linear Sampling of Regenerated Forest). This is based on the L.S.j, but no separate sampling of class A species is undertaken and usually no secondary tree is chosen.

63

AITEKDIX VI B.

Types of machines for removal of vegetation or logging debris in preparation for planting on easy or rolling terrain (from Chavasse 1974).

Primary objective burning No burning required

(i) Grasses, herbs and light shrubby vegetation Rotary choppers or slashers Disc ploughs Roller-choppers or crushers Heavy nouldboard ploughs

Blades (angled or V) Scalpers (with or without rippers) Rippers Scarifiers Rotary choppers or slashers Bedding ploughs

(ii) Moderately heavy shrubby vegetation Bulldozer crushing Heavy chopping or crushing rollers Chain (or ball and chain) Shear blades (angle or V) Root and rock rakes

Bulldozers, root rakes for wind-rowing or heaping (usually following one of these operations; however, windrows are also sometimes burnt)

(iii) Heavy vegetation Uprooting by bulldozer Treu crusher Tree eater Tree pusher (stinger) Shear blades (Very large trees are often felled by powersaw)

Windrowing or heaping as under (ii)

( iv) Stumps (May be removed with one of the tools listed in (iii) and burnt with the other debris, or windrowed)

Angle shear blades Powered stump cutters or chippers Root ploughs Uprooting by bulldozer (Explosives)

(v) Logging debris generally (May be burnt in situ) Bulldozers

Root rakes V-blades

windrowing or heaping

64

Appendix VI C.

Mechanical clearance of the lowland rain forest for Vinus cultivation in Surinam (from: Werkgroep Bosbedrijfsregeling, 1975}.

As PimtB aœribaea cannot stand shade, it is exclusively planted in the open. Thus as much as possible of the existing vegetation on the terrain must be removed and the area levelled. Two methods are applied for clearing: 1) with a tractor equipped with a K.G.-blade; 2) with a tractor equipped with a treepusher.

The KG-blade is an angle shear blade with a stinger on the left side, usually-mounted on a D8 heavy tractor. The shear blade severes all vegetation at ground level (except very large trees) and pushes it aside; the stinger is used first tc split the stem and buttressed roots of thick trees. The tractor clears rectangula patches of 1 to 3 ha, working from the outside to the inside, in counterclockwise circles around the forest to be cleared until nothing is left. As the blade is mounted at an angle, the felled vegetation falls to the outside, and does not hinder the operations. This way of clearing requires a highly experienced operate it also exposes and disturbs the soil. Some weeks after clearing, when the debris are somewhat dried out, windrowing is done by D7 tractors equipped with a rake. The debris are pushed into rows which are about tO-50 m from each other. Usually superficial burning is carried out before windrowing to avoid concentration of nutrients in the rows, to suppress weeds, and to ease the windrowing. The last operation consists of plowing the site with a disc-plow. The principal purpose of this is to make the site sufficiently level for subsequent mechanical operations (e.g. planting and weeding).

A tree pusher is mounted on a tractor» It is put against the stem of a tree, som meters above the ground. This method is quite simple and it requires less trainii of operators, and also the felling direction is controlled better. A disadvantagi is that much soil falls into the rows thus hampering burning: in addition, soil disturbance results from it. Often the windrowing is done by a team of tractors thereby saving considerably on motorclockhours (mch). Observations made clear th< separately working tractors required about 7 mch per ha for clearing, whereas on. 4 mch were needed by a team of tractors.

Capacity: Method 1: D8 + KG-blade, D7 + rake and D8 + disc plow: 13 mch + 4,8 mandays/ha. Method 2: D8 + treepusher, D7 t rake and D8 + disc plow: 13.4 mch; D6 for clear!

afterwards: 1 mch; + 2.5 mandays/ha.

65

Appendix VI D.

Handtools and machines for soil cultivation.

I. Superficial cultivation. 1) Complete and stripwise

scarifier rotary hoe (disc-Hiarrow; diameter of discs up to 70 cm (disc-)plow.

2) Spotwise Manual: spade, hoe, pickaxe Mechanical: Kulla-cultivator, SFI-cultivator.

II. Semi-deep and deep cultivation. 1) Complete and stripwise

mould-board plough disc-plow spitmachine hydraulic excavator • ripper, subsoiler.

2) Spotwise spade planting hole auger (with engine or mounted on a tractor) planting hole grubber.

66

Appendix VI E.

Chemicals used in site preparation of densely vegetated terrains.

1) Synthetic_growth_regulators, based on 2,4-D, 2,4,5-T, MCPA and MCPP. Mostly

aqueous emulsions (usually 2-4 kg/ha) applied to leaves as a spray or mist; less often dissolved in oil and applied to the stem base. Knapsack sprayers are commonly used; less often motor driven sprayers or aircraft are used. Various ways of reducing dangers from volatility and drifting of these herbicides are now being tested.

25 §2ï?èu5LîriÇ.l!i°!i°§S£'têîe.> 50-200 kg/ha, as spray or granules for thorough control of grasses and other weeds. It creates some residue problems in the soil.

3) 5§i§E2S (2,2-dichloropropionic acid), 5-24 kg/ha, as spray or mist or granules for grass control, usually with a knapsack sprayer or motor sprayer; granules also with a helicopter.

4) Amitrol (3-amino-l,2,4-triazolel, with 20 kg active ingredient/ha, sometimes mixed with Simazine (2-chloro-4,6-bisethyl-amino-l,3,5-triazine) or Ammonium thiocyanate. Chiefly used for control of perennial grasses and dicotyledons.

5) Âtrazine (2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine), with 1-3 kg active ingredients/ha, against numerous monocotyledons and dicotyledons weeds. It is mainly applied as an aqueous suspension with a knapsack sprayer, less often with aircraft. Mixtures of atrazine and simazine, or simazine (1-3 kg a.i./ha) alone are also used to suppress growth on mechanically prepared sites

6) §°Ëiym-ârSËSiïê_SS^_§ï5SDSÏë (NaAsO-, Na„As„03), used for poisoning trees and shrubs; applied with a tree injector or by painting with a hand brush.

7) Paraquat (Gramoxone, 1,1-dimethyl-t-dipyridine); 3-5 1/ha; a contact herbicide which rapidly decomposes in the soil. Used for the control of young weeds, mainly monocotyledons; applied with a (motor)knapsack sprayer.

8) Çïayat (Reglone, l,l-ethylene-2,2-dipyridine), 3-5 1/ha; control of young dicotyledonous weeds; often combined with Paraquat to control annual grasses.

9) ?i£i°Eam C*~amino-3,5,6-trichloropicolinic acid), 0,6-1.1 kg/ha. 10) (5ot often used in forestry are: Dinoseb (2,4-dinitro-6-sec-butylphenol),

5.5 kg/ha; Djçamba (3,6-dichloro-2-methoxy-benzoic acid), 2-8 kg/ha.

(From: R0HRIG, 1974; and Plantenziektekundige Dienst, 1974.1

67 T a b l e V I - 6 . L i n e p l a n t i n g anc e x p e c t e d y i e l d , a c c o r d i n g t o c ) CATINOT ( 1 9 6 5 ) .

A. Agathia alba Diptevoaarpua s p p . DryobaUmop8 aromatica Pentaspadon officinalis Sahima ncronhae Shorea s p p .

B. Simaniba amara Virola 8urinamenai8

C. Khaya ivorensie Terminalia. ivoreneia Taxrieta

utilia

^s m S V

>> c o • H +J 10 + J O t£

70

70

70

70

70 70

45

22

6 0 -75

60 -75

60 -75

.-*! S

w

<o <s> c • H

r H

G 0)

<u s +J

o ja ai o c ra • p

n • H Q

12

12

1 3 . 5

1 0 . 5

9 1 5

7

10

10

15

20

1 g r oup p l a n t i n g . Sp l e c i e s u s e d , s p a c i n g a ) WYATT-SMITH ( 1 9 6 3 1 , b l BAUER e t a l .

L i n e p l a n t i n g

m G —' •rt B rH w

h0 c O

H 10

60 C

• H O 10

o. (0

bO

c • H r H • O d l 9)

W

J . 8

1 . 5

1 . 2

1 .8

2 . 1 1 . 5

2

.1 .5

3

3

3

ra j =

^ CO

C ra » r H

o.

o z

432

528

576

504

504 1*20

720

720

200

165

130

ra J 3

u V

cu 0. 0 c< o

r H

ra e • H

•H

O

s

85

85

72

85

120 18

1 0 t

240

2 5 / 50

2 5 / 50

2 5 / 50

ro B

• O r H O

• H

>, •8 + j

o 0>

o. X u

285

86

7 5 / 200

75 /200

7 5 / 200

e \~* tO

o. 3 O G c V

« 2 D J 3

H

ra > b

 B M

12

12

1 3 . 5

1 0 . 5

9 15

5x10

5x10

, r o t a t i o n , anc ( 1 9 7 5 ) , and

Group p l a n t i n g

'S \~* (0

o. 3 O

u M

c • H

-c +J • H 3

r H

ra > u ai + j

fi r H

0 . 9

0 . 9

0 . 9

0 . 9

0 . 9 0 . 9

O i 3 O

Ü. h m o. n M B

•H rH •o O 0) 10

O 2

6

7

9

7

5 8

3

3

ro E

• O r H <D

. H > 1

X I 01 4 J O O

o, X l d

263+54* (+49 )

64+16* ( + 16)

e.g. 64 + 16(+ 16) = yield planting + minimum yield of natural regeneration (+ surplus yield with maximum stocking of natural regeneration). See also table 8.

68

T/IBLE VI 7. Line planting and group planting. Costs of execution and maintenance during the first of a rotation in mandays/ha. After A) CATINOT (l965)t B) BAUER et al (1975), and C) WYATT-SMITH (1963).

Nature of the work Line planting Group planting

Survey and opening up Poisoning and cutting in

the forest Clearing of strips/spots Digging planting holes Planting Nursery Maintenance in year of

planting Tending during next 9

years Overhead TOTAL

Africa (A)

*

1 5 7

10 3

24

10 75

Surinam (B)

2.3§ 7-7^

A h 4 5-

6.6^

Malaysia

(c)

)

) 30 )

6

75

Suriname (B)

2.3| 5.3*

3.51

2*56 2.55

4 -8.6

75.5

6.6Ï 115.8

Malaysia

(c)

2.6

4-9

75

J_ +130 1 Diesel oil with phytohormone 2 + 1 machine labour hour D8 Ï + 36.5 litre 2,4,5-T in Diesel oil 4 + 2 0 litre 2,4,j-T in Diesel oil _5 estimated 264 working days/year 6 + 1 hour tractor+lorry 2 + 3 0 litre 2,4,5-T in Diesel oil 8 maintenance of nurGery roads, equipment, sprinkler equipment

TABLE VI 9. Minerals in the tropical lowland forest (a data review from various

sources). (After VAU ZADELHOFF, 1976).

Organic Nutrients stored in material organic material (tons/ha) (mg/g)

N P K Ca Mg N

180 36O 770

21 75O

) 165

3500

Total

P K

13 63 32 208 55 550

1 8 62 187

7 42

21 210 5746 191 1268

amount

(kg/ha

Ca

90 320 440

9 250

145

500 1995

of minerals

)

Mg

22 80

132 3

125

28

18c 570

Total

368 10C0 1947

42 1374

387

4511 9770

*

4 10 20

• 5 13

3

50 100

Leaves Twigc tc tranche Stem Undergrowth Roots Fine litter Coarse litter Soil C-3O em TOTAL

9 s 80 220

3 125

5 15 50*

507

20 1.4 4.5 .4 3.5 -3 7 .3 6 .5

14 .5 6.5 .3

7 2.6 2.5 2.7 1.5 2.3 3.2

10 4 2 3 2 6 7

2.4 1 .6

1 1 2 1.2

O-5O cm

69

TABLE VI 8. Expected yields_(ijVha) o f line and group planting (after BAUER et äl

elds (m , 1975)

Line planting Group planting

Rotation (years) 22 27 32 38 45 22 27 32 38 45

Diameter olaBS (cm) 35 40 45 50, 55 35 40 45 50 55

No. of thinnings - 1 2 3 4 - - 1 2 3

Stems/ha *>*n 180 148 120 104 180 . 180 148 120 1C4

Stems/ha of natural - - - - - 20 20 20 20 20

regeneration (-40) (-40) (-40) (-35) (-30)

Stems/ha of total 240 180 148 120 104 200- 200- I68- I40- 124-etand 220 220 188 155 134

Yield first thinning 22 22 22 22 - - 21 21 21 22 years

Yield second thinning - - 21 21 21 - - - 28 28 27 years (+10) (+10)

Yield third thinning - 28 28 - - - - 23 32 years (+12)

Yield fourth thinning - - - - 2 3 - - - -38 years

Felling 86 117 146 172 191 64+ 117+ 146+ 172+ 191+ 16 30 40 48 54

(+16) (+30) (+40)' (+46) (+54)

Total yield 86 139 183 243 285 64+ 117+ 167+ 221+ 263 + 16 30 40 48 54

(+16) (+30) (+40) (+46) (+49)

64 + 16 (+16)= yield planting + minimum yield of natural regeneration

(+surplus yield with maximum stocking of natural regeneration).

70

TABLE VI 10.

Some characteristics of perennial herbaceous ans shrubby legumes for soil cover, green manure and erosion control, (after Whyte e.a., 1953).

Plant Characters

Soil Adaptation

Utilisation

SPECIES

Acacia villosa

Aeschynomene amevicana

Alysicarpu8 vaginalis

Astragalus chinensis

Cajanus cajan

Calopogoniim mucunoides

Cassia didymobotvya

C.

C.

C.

C.

C.

hivsuta

leschenaultiana

occidentali8

pumila

siamea

Centrosema plumieri

C. pubescens

Clitoria cajanifolia

C. ternatea

Crotalaria anagyvoides

C. goreensis

C. incana

C. lanceolata

C. mucronata

C. spectabilis

C. usaramoensis

v

c m

O 4-" •H t/l X -H O w +J v

<0 CiO co 4-> t . G X! J=

-M 4-» 'H O » bO y w -u -H a) 3 S> p c x e o h h -H O O h

1 2 3 4 5 6

X .

X X

X X

X .

X X

X . .

X

X

X . . X

X X

X .

. X X

. X X

X .

X .

•M >> J3 >

•o ai

« c 3 -H O tO <D » 3 fc a tl O T) -H

O H r-l m ro -o H 10 *H 'H Ä • * I B J : v O H u u n s x < <

•a •o

fi

u

"8 ? O O

l(H O

E 3

f< 10 _ „ „

C -H (U w ai o u u

1 2 3 4 5 6 7 8 1 2 3 4 5

. . . X .

X X . X .

X . . . X X . X .

X X X

X X X X .

X X X X .

. X . X .

. X .

. X .

. X .

. X X

. X .

. X . X .

X X . X X

. . . X X

. X . X .

X . . . X .

X . . . X .

X X X . X .

X X X . X .

X X X . X .

X . . . X .

Seeding rates kg/ha

broadcast

40

10-20

20-25

15-20

3

3

4-5

20-30

10

15-18

8-12

10-20

20-30

8-12

TABUS VI 10 . con t inued

7I ]

Plant Characters

Soil Adaptation

Utilisation

SPECIES

Deemanthus virgatus

Desmodium adscendens

D.

D.

D.

D.

D.

D.

aanum

gyroides

heterophyllum

nioaraguensie

rensonii

triflorum

Doliohoe bulbosus

D. lablab

Galega officinalie

Glycine javanica

Indigofera arreata

I.

I.

I.

I.

I.

I.

endeaaphylla

hirsuta

retroflexa

suffrmttcoea

eumatrana

tinatoria

Le8pedeza cuneata

Leucaena leucocephala

L. pulverulenta

Medicago sativa

«

IB o *->

•H « X -H O Cl *J +J -H O S 00 O W T3 'H to 3

2 O C X e O

t . -H O O U U CU S H U) Q

1 2 3 4 5 6

. . x

. x

x x

. X

X .

x .

. x x

. X X

. X X

X . .

. . X

X . .

. X X

X X X

X

X

X

X

X

X

X

X

X X

X X

X .

X

w in (0

•H -H 3 O o o w w u

i Si i

^ t i c

>» Sj fH I - M M . > O H r H ffl flfl 60 10 H « ,H -H . * -rl

•rt m n ) x : i u o H o

1 2 3 4 5 6 7

X X

x x

x .

t l - O U ) 

• o o o • o ^ o o

in c -1 iq <H

Ti e o 0) 3 f) > £ H t i * O 0> •• W t l ui tn <o v c 0) t . c O *-• 3 O o « c o

t i a •a v f e c

t i e o C 3 V B -H fl) +-» O 0) M

1 2 3 4 5

X X . X .

. X . X .

. X .

. X .

. X .

. X .

. X .

. X .

X X .

. X

X X

. X

X X

X .

X X

X .

X X

X X

X X

X X

. X

X X

X X

X X

X X

. X .

. X .

. X .

. X X

X X X

. X .

X X .

Seeding rates kg/ ha

broadcast

20-25

20-25

8-10

10-15

10-30

TABLE VI 10. n n n t < w „ ^

SPECIES

72

P l a n t

C h a r a c t e r s

M U C C

'ri (fl H 0 +J •H «H 10 10 X -H Pi o n

+J •• •(-» m tu) m +J C C J= J2

V *-> -H O 3 bO O « f l - H U 3 0> O C X s 5 h b «H O O £

u CL, 3 s - œ Q

S o i l

A d a p t a t i o n

•o 01 ID V

-H H n c •H -H 3 >H 0 0 0 <o n n « 3 t .

U 0 T)

£ > o *-\ H bO 10 *H ro ~H

•H 0) (0 J3 « j i o « a

+J to •H o

E

« c

•rt -1 10 .x H

<

•o •H O

 c V m c o o

o0

c 

3 •M to (0

a ,

t.

•8 g O 0

<*H O

C ^1

g-s 3 tfl J= .H

" O • m t<

«i ai c » f i e +J 3 O to c o u B { i ë C c o <D C -H u a> to c tu o o £ t ,

O O M

S e e d i n g r ;

k g / h a

b r o a d c a s t

1 2 3 4 5 6 1 2 3 4 5 6 7 8 1 2 3 4 5

•fimosa inviaa

Phaseolus calcaratua 3 . lunatua

°ueraria phaseoloidea 3 . thunbergiana

Xkynehoaia phaseoloidea

'tizolobium deeringianum

>. hassjoo

>. niveum

Hylosanthes gracilis

>'. hamata

'uansonia salaula

''ephrosia Candida

purpurea

toxicaria

vogelii

'rifolium repens

'igna oligoaperma

X X X X .

. X X X X .

X . X . X X X .

• X X . . X . X . . . X . X X X . X X

. X X . . X . . . . X . . . X X . X X

. X X . X X .

. X X . . X X X . . X . . . x x x x .

. X X . . X X X . . X . . . x x x x .

. X X . . X X X . . X . . . x x x x .

X X . . . X X X . X X X . X X X . X .

. X . . . X X X . X .

X . . . X X X . . X

X . . X X . . . . X X X

X . . X x . x .

X . . X X .

X . . X . . . X X .

. X X . X . . X . . X X . . X X . X .

. X X . . X x x x x .

6-8

70-80

5-15(unhull.

6-10(unhull.

30-40

30-40

30-40

2

6-7(rows 1,5 m

4-5(rows 1,5 m

5 (rows 1,5m)

4-6

15-20

73 Appendix VI F.

Existing and proposed national parks and reserves in South Vietnam.

A. Existing national narks and reserves (I.U.C.N., 1974). - Kron"PÔkô~(533776Ô"hâ5

Bach Ma Hai Van National Park (78,000 hal - see also B Plei Ku-Plei Ta-Uan-Xer (54,480 ha) Kinder (53,760 ha) Bantur (27,840 ha) Lang Bian (4,800 ha) Trang Bom Park (500 ha)

There are also several hunting reserves.

B. Proposed national parks and reserves (After PHAM H0ANG HO, 1965; and PHÜNG"TRÖNG"NGÄN"1965)"

Lowland : The Con-Son island at the mquth of the Me Kong river, about 100 km from the coast. It has a rich vegetation, it has been relatively well-investigated, and has remained relatively undisturbed. Thus, its flora is a good representative of southern flora of Vietnam. The Châu-Dôc mountains (highest summit: Nui-Cam, 716 m above sealevel). Besides a good number of endemic and rare plant species, this region gives a very good impression of the original vegetation of South Vietnam. The nature reserve Bao Loc, southwest of Blao. This area has an interesting flora and fauna. Here the lowland gradually passes into the submontagnard zone up to 1000 m above sealevel. The game reserve of Duc Xuyên near Ban Me Thuot. The Paracel, Pécheurs, and Deux Frères Islands along the coast. Possibly a reserve for migrating birds can be established on these islands. The Canh Duong Scenic Reserve and Loan Scenic Reserve on the coast. The Cape Varella, one of the few spots in Vietnam where the tropical forest is found at sealevel.

Submontagnard and montagnard zone: The region around the Chu-Yan-Sin, the highest peak of Vietnam (2405 m above sealevel). Ecologically very interesting. The Nui Ba nature reserve with the Lan Bian peak (2163 m above sealevel) about 15 miles east of Da Lat. The Bach Ma Hai Van national park situated in the Thua-Thien and Quang-Nam Provinces (78,000 ha). A summer residence of 1500 ha and a 1000 ha experimental forest of the Applied Agricultural School are found here. It comprises a mountainous area, with the Bach Ma as the highest peak (1450 m). Many Gymnosperms are represented here such as Dacrydium 8pp., Podooarpue 8pp. , Keteleeria spp. . Furthermore, Dipterocarpaceae, Fagaceae, Leguminosae , Sapindaceae and Myrtaoeae are also found here. The area is well-known for its Camellia 8pp. and Orchidaceae. The fauna includes animals such as elephants, bears, tigers, panthers, deer, wild boars, monkeys, foxes, peacocks, pheasants, quails, etc. The region has good opportunities for tourism, in combination with the former capital of Hui, and the several events, museums, etc. in the Quang-Nam province.

Appendix I

Contents

1. Introduction

Page

2. Choice of species 3 2.1 General 3 2.2 Site factors 3

2.2.1 Man 3 2.2.2 Climate 3 2.2.3 Soil 3

2.3 Pests, diseases and calamities 4

3. Appropriate management of bamboo stands 4 3.1 Pure to nearly pure natural stands 4 3.2 Natural regeneration after gregarious flowering 5 3.3 Natural regeneration in vegetation formation with

bamboo in undergrowth 5

4. Stand development 5 4.1 Site preparation 5 4.2 Soil preparation 5 4.3 Planting stock 6

4.3.1 Seed 6 4.3.2 Vegetative propagation by cuttings 6 4.3.3 Other methods of vegetative propagation 9

4.4 Spacing 10 4.5 Planting hole 10 4.6 Underplanting, mixing, and covercrops 10

5. Maintenance and harvest 11 5.1 Maintenance 11 5.2 Harvest 11

6. Bamboo for the control of soil erosion 11

7. Considerations about the potentials of bamboo in Vietnam 12 7.1 General 12 7.2 Appropriate management of natural stands 12

7.3 Planting of bamboo 12

Literature 14

Table and Figures

1-1

Appendix I: BAMBOO SILVICULTURE

1. Introduction

Bamboos are woody perennials varying in height from 15 cm to over 30 m. They form a special branch of the Gramineae; many species are of silvicultural importance because of certain technical characteristics and their locally extensive occurrence. Geographically they are distributed unevenly over the world. They are most widespread in tropical Southeast Asia where they occur as an important component of wet evergreen, moist deciduous, and dry deciduous forests. Both the number of species and the total area covered by them are largest in these forests. The representation of bamboos on the mainland of tropical Africa is small but Malagasy has a much greater variety of bamboo stands. The other continents have a fair to small number of endemic species and genera. However, because of human impact the natural distribution of bamboos over the world has been strongly altered.

Some call bamboo the poor man's wood; others, however, consider it the staff of life. Surely it is of tremendous importance in the everyday life of many people in Vietnam. This is due to the multitude of purposes served by bamboo; it is planted as farm woodland or collected from the forest to serve these purposes. In addition, certain bamboo species are excellently suitable as a source of paper pulp because of their high cellulose content, their size, and their productivity. In many countries in tropical Asia large quantities of bamboo are converted into paper; India is by far the largest producer with 800,000 tons annually (AUSTIN et al., 1970). Austin states, however, that utilization as it occurs at the moment in these countries is not very effective. Often production is limited to small, remote areas, combined with inappropriate management or no management at all. The yield/ha could be greatly increased by taking some simple measures. Because production can start quickly and high yields per unit can be obtained in short rotations, bamboo shows good prospects for pulp and paper production. GROULEZ (1967) estimates that properly managed BarribuBa vulgaris plantations can give an annual yield of 33 tons of green weight or 18 tons of dry weight per hectare. From natural stands in Burma, only 5 tons dry weight bamboo have been obtained (FA0, 1973).

Little is known about pulp and paper production from bamboo in South Vietnam. DREW (1973) mentions the occurrence of a small factory utilizing a non-specified bamboo species. According to PHUNG TRUNG NGAN (1973) the principal Vietnamese bamboo species for pulp is Neohouzeana dullooa; the raw material is obtained from natural stands - this is possible because of the occurrence of vast areas of a single species. Based on this information, the FAO (1962) has drawn a rough exploitation plan for the vast bamboo stands in the province of Phuoc Long and the northwest provinces of Phuoc Thanh and Long Khanh where the stands mainly consist of Sohizoataohyum zollingevi (Lo-o). Because of the war this plan has probably not become reality, but it is advisable to test its suitability and to complement it with good management planning.

Also some attention has been paid to planting in South Vietnam; trial plantings have been carried out in Lang Hanh with Orythenanthera spp., Neohouzeana dullooa, Arundinaria Bpathiflora and Sohizostaahyum zollingevi (NGUYEN VAN THAI & NGUYEN VAN TH0N, 1971).

Knowledge about the propagation and cultivation of most bamboos is still scarce; thus a proper management of natural stands is highly desired and research should be undertaken to develop good propagation techniques for bamboo. One of the difficulties in planning commercial utilization of bamboo is its often unpredictable flowering. Attempt made in Japan to find a relationship between the occurrence of flowering and several factors which might stimulate it, failed. After flowering the clump dies or the vegetative growth is strongly reduced. However, good production is obtained again after 6-10 years. The FAO (1973) advises growing several species in one area in order to guarantee the stand's continuity.

1-2

Before passing on to a discussion of the various silvioultural methods which are appropriate in bamboo propagation, we will first deal with the two great groups into which bamboos can be divided. These are shown in the following table :

Two groups of bamboos, requiring different propagation procedures

Characters Expression of characters

Group I or sympodial species

Group II or monopodial and intermediate

species

Climatic adaptation in relation to temperature

Culm initiation (active growth following breaking of buds on the rhizome) under natural conditions

Rhizome Form of the constituent axes

Form of the lateral buds

Growth habit of individual axes

Clump habit typically

Culm origin

Culm branches (mid-culm range)

Transverse venation of leaf blades

Typical genera

Tender plants that thrive best under frost-free conditions ; some species are known to survive temperatures a few degrees below 0 C without serious damage

Takes place typically during the summer or autumn, or at the beginning of a rainy season following a relatively dry period; apparently is controlled primarily by moisture levels

Pachymorph, i.e., short, thick; internodes asymmetrical, broader than long

Dome-shaped; the apex intramarginal

Determinate

Caespitose; the plant a single dense tuft of culms

Distal to the rhizome

Basally swollen; recapitulating the form of the rhizome; the dominant ones often bearing root primordia of spontaneous origin in situ

Frost-hardy plants that thrive best in climates with a marked, but not extremely cold, winter; a few species can survive temperatures a little below 0 C without serious damage

Takes place typically in the spring, at the onset of favorable levels of temperature; apparently is controlled primarily by temperature levels

Leptomorph, i.e., long slender; internodes symmetrical, longer than broad

Boat-shaped; the apex distal

Indeterminate

Diffuse; plant with culms distant from each other

Normally lateral to the rhizome

Basally not swollen; not recapitulating the form of the rhizome ; not known to bear root primordia of spontaneous origin in situ

Usually obscure Clearly manifest

Bambusa, Dendroaalamus, Arundinaria, Phyllostaahye, Elytrostachys, Gigantoohloa, Sasa, Semiarundinaria, Guadua, Oxytenantheva, Skibataea, Sinobambusa Schizostachyum

After McCLURE, 1966.

The majority of the South Vietnamese bamboo species belong to Group I.

1-3

2. Choice of species

2.1 General

as stated above, much bamboo is obtained from natural stands. In South Vietnam bamboo occurs in more or less pure stands, but also in the undergrowth of various forest formations (see main report III-3). As a minor forest product, bamboo serves a multitude of purposes. Where pulp and paper production are concerned, then species, dimensions of the stands, infrastructure, and possibilities for the establishment of a factory are going to play a part. First, the suitability for pulping of certain species needs to be investigated. Areas showing favourable prospects with respect to this can be put into production. Measures need to be taken to obtain optimum production in the future and to keep it like that. These measures may include operations in the forest canopy or in the stands themselves.

In addition to utilization of natural bamboo stands, it is possible to establish plantations. In large areas this will probably be done for pulp and paper production only. However, on many small areas intensive planting of various bamboo species will be done for the multitude of other utilisation possibilities. Important species for pulp and paper production are those mentioned in table 1 (after FAO, 1973), Dendroaalamus asper Backer and Barrbusa blumeana (DREW, 1974). McCLURE (1966) mentions Barrbusa vulgaris as a species with many possibilities including pulp and paper production, and that it has favourable characteristics for planting. Promising or suitable species in the Philippines are Gigantoahloa aspera Kurz., Schizostaahyum lumampao (Blanco)Merr. and Barrbusa vulgaris Schrad. ex Wendl. (VELASCO et al., 1973). Species suited to various utilizations are Barrbusa blumeana and B. arundinacea (DREW, 1974). A choice for planting has to be made on the basis of the local ecological conditions.

2 - 2 §ite_factor;s

2.2.1 Man

Human interference has a very strong impact on the distribution of bamboo. In the main report III.3 and IV.3.2. something has been said about the human influence on bamboo distribution in South Vietnam. Much of this holds for the major part of the world where bamboo occurs.

2.2.2 Climate

The majority of bamboo species thrive at temperature ranges of 9 to 36 C, although species of the monopodial type may occur in regions with temperatures slightly below the freezing point. For the individual species, rainfall is an important factor; it seems to require at least 1000 mm annually. The maximum quantity is not known but some species are found in regions with over 6300 mm of precipitation. The most common range is 1250-4000 mm of annual rainfall. In high rainfall zones many species with a climbing and tangling growth can be observed. Relative humidity is correspondingly high and ranges from 80% upward. The distribution of the individual species is mainly determined by temperature and rainfall and partly by soil conditions. Often they have rather sharply defined ecological der.ar.ds. Therefore, for instance in Pakistan, bamboos are very good indicators cf certain forest types. (SETH, 1957).

2.3 Soil

Bamboos usually prefer well-drained sandy loam to loamy clay soils with good fertility, as for instance river alluvium or freshly weathered material. However, some species are found on less well-drained soils and many on less fertile soils. From the above it becomes clear that the ecological demands of most species are

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not exactly known. When introduoting an economically valuable species in regions where it does not occur naturally, investigations into these demands will be required. An indication is given by the forest type in which the concerned species naturally occurs.

2 •3 Ç2§î§.i_^i!ÊËSÊ5.i_§DiLc.§i5ï!itîes

Few serious insect or disease problems in bamboo stands are reported. If culms are cut too young, decay may result. A top borer (Estigma chineneis) may present some problems in bamboo stands. Much more serious is the powder post beetle which can render bamboo culms useless after felling; three Dinoderus 8pp. are concerned (P. brevie, D. mùnutua, D. ocellœri.s'ï. Control is achieved by cutting the bamboo in the cold season when the beetles are less active, and keeping the cut culms in water to leach the disaccharides on which they feed. Also chemicals or heating in a kiln can be effective. Fire and grazing are injurious agents, although bamboo is able to recover after burning and some grazing. Animals which eat the young sprouts and trample the stands, are especially injurious. Wind can do some damage in overcut areas.

3. Appropriate management of bamboo stands

3.1 Pure_to nearly_j>ure natural_stands

The system used in bamboo forests should he selective cutting by the clump and not the area. The following factors are of importance for good management: a. Felling rotation:

important factors in determining the length of the rotation are the minimum age at which the culm is exploitable, the age at which it is mature, and the total age of the culm. For Dendrooalamus atriotua (SETH, 1957) these are respectively , 5-6 and 7-8 years. When it became clear that the clump was quickly exhausted at too-short rotations, and that the tangling was too severe at long rotations, the optimum felling rotation for this species was fixed between 3 and 5 years.

b. Felling intensity: during exploitation it is important not to take too many culms from the clump, nor too few. If too many culms are taken away the vitality of the clump drops and the mechanical support for many culms is lost. On the other hand, if too few culms are taken the young sprouts are hindered in their growth, finally resulting in poor quality bamboo and congestion of the clumps (figure 3). First the oldest culms must be removed when cutting. The total number of culms to be removed depends on the position of the stand and the felling rotation. General cutting rules have been developed for Dendrooalamue etriotua in India (SETH, 1957): 1) The culms should be cut according to the selection principle. The

remaining culms should be divided over the clump, so that support for the young culms is given, and the clump stays open.

2) Immature (one-year-old) culms are cut only when diseased. 3) Older culms that will die before the next felling should first be

taken and the young and sound culms should remain. 4) No felling should occur at the periphery of the clump. 5) Cutting should be done low (15-30 cm above the ground) and just above

an internode. 5) Together with felling, cleaning needs to be carried out during which

dead, sick and malformed culms are removed. PRASAD (1948) presents about the same rules for Bambusa arundinacea; the number of older culms to be left is 8 to 10 on every clump.

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To favour the sprouting of the rhizomes it is advised to prune at the beginning of the rainy season, which means the removal of all branches from the culms up to 2 meters in height. The areas must be protected against cattle and wildlife as they eat from young sprouts and trample the rhizomes. AHMED (1957) states that cleaning of the clumps is advantageous to relieve congestion, promote regeneration and facilitate harvesting. Although the selection system is by far preferable because of its short felling cycle and higher yields, clear cutting can be applied also. This has the advantage of simplicity, concentration of work, and possibility of mechanization. On the other hand the clear cutting system has the disadvantage that after cutting the clumps are more liable to deterioration and mortality.

3.2 Natural_regeneration_after_gregarious_flowering

Following gregarious flowering and dying of the old clumps, clear felling takes place after the seed has fallen. A good regeneration by seed can be obtained only in this way. The soil must be bare to ease germination and initial growth which occur at the start of the following rainy season. Soil preparation can be advantageous. During at least 3-4 years the area should be protected against grazing and fire. To get a good plantation only those seedlings should be kept which are at the right distance from each other (see 4.4). Tending after 4-8 years is favourable but often economically not feasible.

3.3 Natural regeneration_in_vegetation_formation_with_bamboo_in_undergrowth

At places where bamboo is shaded by a thin canopy of economically useless tree species, these can be poisoned so that a pure bamboo stand is obtained. Some authors state that the keeping of some trees might have a positive effect on certain bamboo species (BROWN, 1918, and CHATUVEDI, 1928). The latter author mentions that 30 trees/ha with a light crown (e.g. Anogeiseus latifolia or Lager— Btroemia parviflora) over Dendrooalamus striotus resulted in the formation of longer and thicker culms. If valuable tree species occur with an undergrowth of bamboo but the united occurrence is not economically feasible, after exploitation of the area, a strip-wise poisoning of trees might be carried out. Within the cleared strip, which should preferably run E-W and have a certain width, a pure bamboo stand is created while the remaining forest can be made more profitable by means of silvicultural treatments. For both systems much research will be required to come to a durable system. For bamboo particularly the number of slumps and culms to remain per ha and the width of the strips will be involved.

•4. Stand development

4.1 Site preparation

(Refer to main report VI.3.4.1). Before planting Bambusa Vulgaris on the African savannah, stumps were removed, the grass was mown and superficial and deep ploughing was carried out in order to remove all grass roots. As this method proved very expensive, it was studied whether cheaper methods, e.g. clearing of strips, was feasible (GROULEZ, 1967).

4.2 Soil preparation

According to VERHOEF (1929) soil preparation is not needed on loose humic soils. The only thing to do is cut the noxious woody plants, and mow the Imperata cylindrica in order to prevent fire. On heavy soils and on Imperata fields ploughing is required and the planting holes must be deeper. Some soil cultivation is required prior to direct seeding; the soil should be bare.

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4.3 Pianting_stoçk

New bamboo plants can be obtained by seed or by vegetative propagation. The method which is used depends mainly on the species.

4.3.1 Seed

Sowing is only occasionally employed, because flowering occurs at long intervals, irregularly, while fruiting may not take place at all. Heterogeneous planting stock is often obtained from seed. Sowing is done when valuable species with insufficient planting stock are used, or if exotic species which have to be imported, are needed, or if a large quantity of stock is needed.

In India Dendroealamus etviotus is propagated by seed if large areas are to be planted. The technique is as follows (WAHEED KHAN, 1972): Eight months before field planting, the seed is sown in polythene pots. Sometimes sowing is done on beds followed by pricking out in polythene pots after one month. The pots contain a mixture of loamy soil and well-rotted manure. The pots are well watered and stand under light shade during the initial stage. At the beginning of the rainy season the 45 to 60 cm high plants are transplanted into the planting holes. . McCLURE (1966, after WHITE , 1948) states that "growing plants of Bambuaa arundi-naàea from seed is undoubtedly the most economical and convenient method of propagating large numbers of plants." Little is known about the viability of the seed. Banibuea arundinaeea is best kept at room temperature with CaCl . Dendroealamua stviotus showed a fair germination capacity after airtight storage for two years.

4.3.2 Vegetative propagation by cuttings

Three methods are used for this : a) Clump division

With this method, use is made of a part of the clump (one or more rhizomes together with the lower part of the culm). A disadvantage of this method is that many mother plants or large parts must be lost to get planting stock. Yet, this method is the traditional one, and for a large number of species the most often applied method of vegetative propagation. This is because it is the easiest and most successful method up til now. Season of preparation. The best time for the processing of vegetative propagule is just before the initiation of bud growth in the axes is involved (once the buds have started to grow, the quantity of reserve food in the rhizome will rapidly decrease). For bamboo species of Group I the best time is during summer (Japan, China), or just before the beginning of the rainy season (India. Pakistan). For bamboo species of Group II the spring (Japan, China) is most suitable since the start of the sprouting coincides with the occurrence of a favourable temperature. Size of propagule. The highest degree of success in terms of survival rates and rates of subsequent development (and the simplest, least exacting in regard to care after planting) is obtained by dividing a clump into two equal-parts. However, very little new planting material is obtained. At the other extreme are propagules, composed of the lower part of a single culm with the rhizome axis basal to it ("offsets"). Advantages of offsets over larger propagules are: ease of preparation, accessibility of material of optimum age, and economy of material. The principal disadvantages are their more exacting demands in regard to care after planting and a lower survival rate.

White, D.G. (1948). Bamboo culture and utilization in Puerto Rico. Puerto Rico Fed. Expt. Sta. Cir., no. 29.

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For certain Bamboo species (e.g. Dendrocalamua etrictue and Bambuea tuldotde single-culm divisions are the traditionally preferred method of propagation. For others (for example Bambuea textilial offsets with two culms left togeth (two-year old "mother" and one-year old "daughter"1 have given better surviv rates or yields (McCLURE, 1966). Age of material. In small clump divisions, the age of the rhizome agRears to be of critical importance. According to McCLURE (1966, after DEOGUN , 1937) 1- or 2-year-old offsets of Dendrocalamua atriotua gave superior results, while propagules consisting of material 3 years or more in age give progressively poorer results. Usually material of optimal age is selected from the periphery of the clump and then cut. It requires experience to learn where and how to find the place where a cut is to be made. The rhizome of Group I bamboos should be severed only at one point - at the neck of the oldest rhizome axis in the propagule. The cut should be made at the slender neck in order to minimize damage to the rhizome and keep the raw surface as small as possible. Moreover, the tissues at this point appear to have a greater resistence against decay. Preferably the cuts should be made with a saw, and propagules should be fist-seized. , For Group II, either one or two cuts may be needed depending upon the orientation of the propagule to the rest of the plant, and the rhizome needs not to be severed at the neck. According to AUSTIN et al (1970) healthy rhizomes are yellow and have good buds; the best length is 30-100 cm with over 20 buds. Before being lifted, the aerial part of the propagule may be pruned before the roots are severed - or promptly thereafter - in order to minimize loss of water through the leaves. It is advisable to retain as much foliage as possible, ample irrigation and protection of the propagule from sun and wind should keep it from wilting until the root system is re-established. The size of culm length to retain varies; advises of various authors lay between 30 and 150 cm. Keeping the roots in a ball of earth is also advised. Successful propagation by single-culm clump divisions are reported with Bambuea tuldotdes, Dendrocalamua atvictua, Melocanna baoaifera and Oxythenan-thera abbeaainica (McCLURE, 1966). According to the latter (from DEOGUN, 1937) this method was the only successful method of vegetative propagation for Dendrocalamua atrictue. The divisions are at best immediately planted; if this is not possible, they can be stored in the shade under moist cloths,

b) Rhizome cuttings

With this method, referred to as "rhizomes alone" by McCLURE (1966), only the subsurface parts are used, without culms but with dormant buds. According to the above, published knowledge about propagation of bamboos is very meagre for Group I. The rhizome cuttings of Group I bamboos are always planted directly in the field. They are convenient for this because they are lighter and less bulky than clump divisions. Units embracing two or more axes left attached to each other might give better results with some bamboos, but their convenience is less. The simplest procedure is to take away single rhizomes from the periphery of the clump. McCLURE (1966) found that decay often developed in the rhizomes. Sterilizing the freshly cut surface at each end of the rhizome with a 10% aqueous solution of Chlorax for five minutes, drying and then sealing the ends with melted paraffin, reduced the losses to a negligible percentage and also increased the period during which the rhizomes continued to produce new plants. Other major problems were the meagre development of roots, and how slowly the rhizome buds would break dormancy in most species. Species of Group I most suited for propagation by rhizome cuttings seem to be Gigantochloa apus and Bambuea longiepiculata (McCLURE, 1966).. Some species of Group II can be propagated by rhizome cuttings.

*) DEOGUN, P.N. (1937). The silviculture and management of the bamboo Dendrocalamua atriotua Nees., Ind. For. Rec. no. 2.

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Bamboos that do not propagate readily from rhizomes alone are generally characterized by 1) the frequent occurrence on the rhizome of nodes without buds and 2) a noticeable scarcity of roots on the rhizome (McCLURE, 1966). Of suitable species, use is made of 2-3 year old rhizomes with many small thin roots; they are cut in pieces 45-60 cm long with 10-15 nodes. Usually the cuttings are planted in a horizontal position in propagating beds at a depth of ca. 20 cm. McCLURE (1956, after TSUBOI , 1913} advises a depth of 7.5 cm and intervals of 17.5 cm, and stresses an important point: keeping the material moist from the time it is dug up until it is put into the propagating bed. The soil in the beds should be loose and moist, and shade should be provided. According to McCLURE (1966) bamboo species of the genus Phyllostaehye respond readily to propagation by rhizome cuttings. AUSTIN et al (1970) recommends this method in case the material has to be transported over some distance (then the material should be packed into moist moss),

c) Culm cuttings Use is made of whole culms, culm segments, or single branches with this method. Culm cuttings are not suited for all species and the survival rate is lower than with rhizome cuttings. According to McCLURE (1966), particularly bamboos of Group I have been successfully propagated by this method up till now. VERHOEF (1929) mentions the following species as being propagated in practice by culm cuttings: Bamboo arundinacea, B. spinoza, B. vulgaris and Dendro-calamu8 asper. One of the disadvantages of this method is that it is rather labour-intensive because the cuttings have to be planted in nursery beds first, and initial growth and tillering is slow. Compared with rhizome cuttings it takes several years more to get culms that can be harvested. The great advantage of culm cuttings is, however, that the underground parts of the clump are not damaged and that much propagation material is obtained. In addition, the plants which are obtained are uniform, which is, essential in experiments, and is profitable in transport and packing. If one should succeed in finding the suitable conditions for successful propagation with culm cuttings, then this method would be preferable to rhizome cuttings and clump divisions.

One species that is readily propagated by culm cuttings is Bambusa vulgaris. Direct planting of culm cuttings of this species proved successful in Africa (GROULEZ, 1967).

- Whole culms

These are buried horizontally; young shoots emerge with root development at the same time. These shoots gradually become culms. This procedure should be carried out at the beginning of or during th« rainy season. Group I. - Experiments by McCLURE and KENNARET* (1955, in McCLURE, 1966) strongly suggest that the age of the culm, and position of the stem within the culm, are variables of importance in relation to yield. Of the 11 bamboos involved in these experiments, Bambusa ventriooea and Gigantoohloa apus responded well to propagation by whole-culm cuttings, the first particularly with 2-year-old culms, the second with 3-year-old culms. Group II. - Whole-culm trial attempts of this group have been few and unsuccessful.

- Culm_segments

Group I. - Culm segments embracing one or ususally two or more nodes bearing buds or branches. The branches are usually pruned to a length of 10-30 cm; no foliage is retained. The cuttings are usually set upright or at an angle, with at least one node well covered (fig. 1 and 2); sometimes, however, they are laid horizontally in the soil.

*) TSUBOI, I. (1913). Jikken chikurin zosei-ho. Translation by R.A. Young (1936). Title: Methods of bamboo propagation.

McCLURE, F.A. and W.C. KENNARD (1955). Propagation of bamboo by whole-culm cuttings. Proc.Am.Soc.Hort.Sci., 65.

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This method is commonly used for certain species (such as Banibusa vulgaris) which propagate readily by almost any of the conventional methods. WAHEED KHAN (1972) used 2-year-old or older culms of Bambusa vulgaris in an experiment. They were harvested on a cool, rainy day, cut into pieces and stripped of branches; the freshly cut surface was oiled. Results in terms of growth, height, thickness, culm production, and survival were from good to slightly less good in the following order: 1) 3-node cuttings from the middle part of the culm; 2) 2-node cuttings from the upper and lower part of the culm; 3) 3-node cuttings from the upper and lower part of the culm. In the above experiment 1-node culm segments were also used. In Dehra Dun (India) prospects of successful propagation by this method include: Dendroaalamus striatus, when 90 cm long cuttings from two-year-old culms are planted horizontally 30 cm below the soil surface; Dendroaalamus longispathus,Bambusa polymorpha, Bambusa tulda; and Thyrsostaehys^oliveri from segments of two-year-old culms (McCLURE, 1966, after DABRAL , 1950). All authors point out the importance of adequate moisture supply, especial! during initial development. Artificial stimulation of bamboo root growth wi moist air is reported by McClure (1966, after VAN OVERBEEK, 1945, personal communication). Group II. - Propagation fulfilling the conditions for success can be securer from bamboos of Group II, when using the lower cut of a small culm where there are many buds or by using the underground part of the culm where the nodes often have dormant buds. According to McCLURE (1966 ) very few references to the use of culm segments or branches of bamboos of this group coul< be found, but this may be due to the crudeness of the methods used rather than to the source of the material. Propagations by this method probably should be more successful when culm segments with branches are exposed to a controlled range of temperatures and humidity.

Group I. - Side branches are cut close to the culm. According to McClure (1966) single-branch cuttings should be made, as a rule, only from root-bearing dominant central axis of branch complements in the mid-culm range. Successful propagation by branch-cuttings is reported for Group I bamboos only: Bambusa vulgaris, B. textilis, Gigantoahloa opus, G. vertioula and Dendroaalamus asper. HILDEBRAND (1954). reports that the rate of survival is low with this method, and that it is a rather laborious one as the cuttings should be planted in the nursery first. In Bangladesh, with varying success, propagation material is obtained from side branches (40-50 cm long) of a thick-walled bamboo species. The develop' ment of good material takes 20-24 months; a single culm can give 50-60 propagules (HASAN et al, 1976).

4.3.3 Other methods of vegetative propagation

In contrast to the above methods, the removal of the propagule from the mother plant is delayed until it has established roots in a propagating medium. Three possible methods are mentioned: a) Layering. Either a whole culm or only the branch-bearing part of it is bent

down to the ground and fastened into a shallow trench (with or without notching it below each branch-bearing node) and is covered with earth or any other suitable medium.

b) The stumps of severed culms are covered with a suitable growth stimulating medium.

c) Aerial layering. The base of each branch complement in the mid-culm range is surrounded with a suitable rooting medium, with or without notching beloi each branch complement.

DABRAL, S.N. (1950). A preliminary note on propagation of bamboos from culm segments. Ind. For., 76.

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The first method is very laborious and is only suitable in unusual circumstances, or for very small bamboos. With the second method, rooted plants were produced by a few species (e.g. Bambusa longispiculata). No successful reports have been givei for the third method.

4.4 Sgacing

Spacing is dependent upon (see also main report VI.3.4.3): the species used and the soil (on fertile, moist soils the spacing can be wider than on poor, permeable soils). It is advised to set the cuttings or young plants immediately at the correct spacing since the removal of clumps is very laborious. Attention has to be Raid to the fact that the clumps enlarge rapidly (with many species to several m ) and that room is needed for the regular harvest of the culms. However, too wide spaci may easily result in strong weed growth. HILDEBRAND (1954) states that two small clumps probably produce more than one large clump. He recommends the row- or so-called pagger-culture (Indonesia) which has the following advantages:

Adequate room for the labourers and for interplanting after the abandonment of the culture; Full sunlight when orientated east-west.

Planting should be done on the contour. For clump forming (Group I) bamboos, HILDEBRAND (1954) gives the following spacings for Java (Indonesia).

small bamboos

medium bamboos

large bamboos

or

or

or

3 x 1.5 m 4 x 2 m 5 x 2.5 m 6 x 3 m 8 x 4 m

10 x 5 m

2180 1250 800 528 300 200

Special spacing is not needed for Group II bamboos as their aggressive rhizomes go in all directions.

For a Bcmibuea vulgaris plantation in Congo Brazzaville (in a region with 800-1500 mm of rain) a spacing of 8 x 8 m or 10 x 10 m is recommended; 6 x 6 is considered too narrow (GROULEZ, 1967). For dry zones in India WAHEED KHAN (19' advises planting Bambusa vulgaris at 12 x 12 m ; the reason for this wide spacing might be the competition for water between the clumps.

4.5 Pl§nting_hole

Commonly the dimensions of the planting hole are a depth of 30 cm and a diameter of 30-45 cm. . For the planting of offsets, HILDEBRAND (1954, after WHITE ', 1948) gives the following instructions: Dimensions of the hole: 30 x 30 x 30 cm; at the bottom of the hole 5 cm of humou: material or manure is placed. The earth around the rhizome has to be heaped up to reduce the risk of desiccation. Around the culm, 5-8 cm of earth is accumulat' On slopes the rhizomes are planted upwards of the culm. Various methods are in u for culm cuttings (figs. 1 and 2), but most important is that they do not desicc. Culm segments of Bambusa vulgaris are directly planted at the bottom of furrows (GROULEZ, 1967). In dry zones soil tillage is recommended at the planting spot to get maximum water conservation. The best season for planting in Japan is October, November, and December for Group II bamboos; in tropical Asia, the rainy season in spring and early summer is best for Group I bamboos.

4.6 Underplanting, mixing, and covercrops

According to HILDEBRAND (1954) both quantity and quality are greatly improv when bamboo grows in full light. Bamboo can tolerate some lateral shade, but no

*^WHITE, D.G. (1948). Bamboo culture and utilization on Puerto Rico. Circular 2S Fed. Expt. St. Puerto Rico.

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overhead shade. McCLURE (1966) states, however, that a certain amount of overhe cover is necessary during the earliest stages of development of bamboo seedling of Dendrocalamus striotus (before they actually form clumps). A certain amount overhead cover improves the quality of the bamboo at the expense of quantity. In case of strong prevailing winds, the establishment of windbreaks is advised in order to avoid congestion of the culms. A species suitable for interolanting of bamboo is Tephvosia maxima (HILDEBRAND, 1954 after SOERAUIMAT, 1938 ). Leucaena leucocephala is considered not suitabl because it hinders the bamboo, and pruning requires a lot of time and money. REILINGH (1921) mentions the possibility of cultivation of food crops during th first two years of bamboo establishment (because of the wide spacing).

5. Maintenance and harvest

5.1 Maintenance

During the first year regular beating up of desiccated cuttings and cuttin that stay green but do not form sprouts, is needed. The only maintenance on wel drained humous soils consists of cutting the newly sprouting shrubs, and fire protection. The top soil around the plants needs to be loosened now and then on poorly drained soils, following initial soil preparation during establishment. If Imperata grass is present, it has to be mowed regularly.

5.2 Harvest

Already 4 to 5 years after planting a first harvest by means of selective cutting can be carried out. At the same time, or even slightly before, a carefu thinning can be carried out, which means the removal of crooked, diseased, and too small culms. According to GROULEZ (1967) the first harvest of Bambusa vulgaris by selective cutting should be carried out 6 to 7 years after planting; in each rotation of 2 to 3 years 50% of the material should be taken. He adds that research is required to determine the optimum time for beginning the felling rotation, number of culms to be removed per rotation, and at what time the highest yields can be expected; this should be done in ,every new planting region.

6. Bamboo for the control of soil erosion

Certain characteristics of bamboo make it very suitable for erosion contre its extensive, dense root system; its rather dense foliage; its felling possibility after which new sprouts are produced; its readiness for propagation (e.g. by clump division).

Bamboo grows best on rich, moist sandy loam; however, it does fairly well on poorer soils. In Puerto Rico bamboo is planted on steep slopes to check landslides (WHITE & CHILDERS, 1945). Bambuea longiepiaulata Gamble ex Brandis was planted there at 6 x 6 m; because this species drops many leaves it gives good ground protection, even on slopes of 52%. Along roads Bambuea vulgaris Schrad. proved very successful in checking landslides. The species forms thick clumps, has a fast dense growth, and is readily propagated. Bamboo was also successful riverbank protection; at erosive positions, e.g. sharp bends, a mat of bamboo was placed through which bamboo culms were planted. It is important to note tha bamboo does not slow down nor obstruct water flow. WHITE i CHILDERS (1945) recommend the use of species which are relatively resis against powder post beetles, and which have industrial applications; they menti Bambuea textilis, B. tulda, B. longiepiaulata and B. tuldotdee.

*'S0ERACHMAT, R.M. (1938). De cultuur van bamboe in het bosdistrict Djember. Het Bosch. (The stands of bamboo in the Forest District of Djember).

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CLARE & GERLACH (1969) point out the possibility of using bamboo as a shelterbelt since it is rapidly established; in 3 to 4 years a dense fence can be formed. Compared with tree or shrub species used in shelterbelts, bamboo requires a relatively small width only (about 3 m ) . The density of the fence will depend on the bamboo species chosen. The following disadvantages of a bamboo fence are mentioned it lodges birds and rodents; and it can cause a fire hazard. The first point mentioned, however, has some advantages as well when these animals play a part in insect control and processing of waste. Planting of bamboo is done at a mutual distance of 90 cm. Protection against cattl is required.

7. Considerations about the potentials of bamboo in Vietnam

7.1 General

In natural conditions bamboo forms an important component in the undergrowth of the dry deciduous forest and the woodland; to a less extent it is important in the moist semi-deciduous forest, the moist deciduous forest and the moist evergreen forest. Furthermore, it occurs in pure stands and mixed with hallier (see main report III.3). As a consequence of various war actions, the bamboo area probably has strongly extended locally (see main report IV.3.2).

7.2 Aggrogriate_management_of_natural stands

After an inventory of the species and the extent of their area, it should be determined which areas are suitable for exploitation. Important factors in this respect are:

Suitability of the species for (in most cases) pulp production, and also for construction. Information about which species can be used for pulp is particularly scarce, thus much research is needed. Geographical position and opening up of the area. Much labour is required foi felling, transport and processing. A good road is not necessary in all cases, but if not present, a river is required for transport. The latter case gives the best possibility for good planning of a factory.

To create a sustained system, research is required to find the right felling rotation and intensity of the species concerned. First considered for exploitation are the pure natural stands; if bamboo occurs in small stands in between or in the undergrowth of a forest, consideration should be given to what is most valuable and what will show the best opportunities in the future: the bamboo, the tree species or both.

A sustained management system of both might be possible in the "forêt dense" on soils developed on schist or granite. Here species like Oxytenantheva dinhenaia and Bambusa procera occur under a thin canopy of (mainly) Leguminosae. Since in tl consulted literature nothing is mentioned about the pulping potential of these twi bamboo species, this has to be determined in case of combined exploitation.

In other vegetation types where bamboo is found spread over smaller or large] areas, interference in the canopy of the forest or a stripwise liberation of the bamboo is required in order to favour the development of bamboo (if the bamboo is desired!). However, probably the tree species will be preferred in the vegetation types concerned (dry deciduous, moist semi-deciduous, the moist deciduous am the moist evergreen forest). Usually the tree species are more valuable, and the bamboo can be obtained cheaper from pure stands and possibly from the "forêt semi dense".

7.3 Planting_of bamboo

Large-scale planting will mainly be done for pulp and paper production. At this moment the processing industry is mostly situated near existing natural stands in order to depress transport costs of the raw material. Large advantages arise from planting bamboo in the neighbourhood of a pulp factory together with

1-13.

fast-growing tree species: supervision on production and planting; low costs of transport and storage; the factory can be built at a place which is most favourable with respect to labour supply, infrastructure, etc.

A great problem in plantation establishment is, however, that at this moment for many species no satisfactory method of propagation exists: it seems wise to start research on this problem. In addition, species which are readily propagated (like Bambusa vulgaris) may be planted in trial fields.

In view of the scarce knowledge existing about the ecological requirements of many bamboo species, it is advisable to try suitable species found in the region first. Considering the often unreliable flowering and subsequent dying of bamboos, it is recommended to have two or more species in a certain area so that the production can always be continued.

Finally, planting can be done for erosion control, particularly to control landslides along roads. Species that are readily propagated by clump divisions are most suited for this.

1-14

Literature

Ahmad, Y.S. (1957). Bamboo. Tropical Silviculture vol. II F.A.O. Forestry and forest Products Studies no. 13.

Ahmed, K.J. (1957). Methods of increasing growth and obtaining natural regeneration of bambootype in Asia. In: Tropical Silviculture vol. II. F.A.O. Forestry and Forest Products Studies no. 13.

Austin, R., D. Levy I K. Ueda (1970). Bamboo. Walker/Heatherhill, New York S Tokyo.

Brown, W.H. (1918). Philippine bamboos. Bulletin Bureau of Forestry, Dept. of Agriculture and Natural Resources Phil. Isl. no. 15.

Champion, H.G. (1968). General silviculture for India. Chatuvedi, M.D. (1928). Influence of overwood on the development of bamboo

(DendrocalamuB atriatus). United Provinces Forest Department Bulletin no. 1. Clare, R.J. X J.C. Gerlach (1969). Bamboo for shelter on pumice soils. New

Zealand Journal of Agriculture 119. Drew, W.B. (1974). The ecological role of bamboos in relation to the military use

of herbicides on forests of South-Vietnam. Workingpaper of the committee on the effects of herbicides in South-Vietnam, part B.

F.A.O. (1962). Pulp and paper development in Asia and the Far East. Proceedings of the conference held in Tokyo, 17-31 Oct. Vol. II.

F.A.O. (1973). Guide for planning pulp and paper enterprises. F.A.O. Forestry and Forest Products Studies no. 18.

F.A.O. (1974). Tree-planting practices in African Savannas. F.A.O. Forestry Development Paper no. 19.

Groulez, J. (1967). Creation des bambusaies à Bambuaa vulgaris sur sols de savanne au Congo Brazzaville. World symposium on manmade forests and their industrial importance. Canberra, 1967, vol. III.

Hasan, S.M., J. Skoupy & E. Vaclav (1976). Recent trends in bamboo gr.owing and US' in Bangladesh. Silvaecultura tropica et sub-tropica 5.

Hildebrand, F.H. (1954). Aantekeningen over Javaanse bambu-soorten. (Notes on Javanese bamboo species.) Rapport van het Bosbouwproefstation, no. 66, Bogor

Huberman, M.A. (1959). Bamboo silviculture. Unasylva 13. McClure, F.A. (1966). The bamboos. A fresh perspective. Cambridge, Mass. Harvard

University Press. Ngyuen-Van-Thai t Ngyuen-Van-Thon (1971). La station expérimentale forestière

de Lang Hanh. Phung Trung Ngan (1973). Natural products of the lowland forests in the Republic

of Vietnam. Pre-congress conference, Symposium Planned Utilization of the Lowland Tropical Forests, Java, 1971.

Prasad, J. (1948). Silviculture of ten species of bamboo suitable for paper manufacture. Ind. For. 74.

Reilingh, A. (1921). De bamboebosschen en de exploitatie daarvan in het Bosch-district Besoeki. (The bamboo-forests and their exploitation in the forestry district of Besoeki.) Tectona XIV.

Troup, R.S. (1921). The silviculture of Indian trees, vol. Ill Clarendon Press, Oxford, England.

Velasco, J.R. & J.V. Santos (1973). Destruction and renewal of lowland forests in the Philippines. Pre-congress conference, Symposium Planned utilization of the lowland tropical forests, Java, 1971.

Verhoef, L. (1928). Bamboecultuur op Java. (Bamboo stands on Java.) Korte mededelingen van het Proefstation voor het boschwezen no. 15.

Waheed Khan, M.A. (1972). Propagation of Bambusa vulgaris - its scope in Forestry. Indian Forester 1972 (98).

White, D.G. 8 N.F. Childers (1945). Bamboo for controlling soil erosion. Journal of the American Society of Agronomy. 1945.

Seth, S.K. (1957). Natural regeneration and management of bamboos. Tropical sil-vilculture, vol. II. F.A.O. Forestry and Forest Products Studies no. 13.

1-15

Table 1 - Principal bamboo species used for pulp and paper

Species Fibre length Chemical analysis

Maxi- Mini- Average(country) Cellu- Lignin Pento-mum mum lose sans

Bambitaa arundinaoea B. bamboe B. atenoataahya B. tulda Dendroealamua atriotua

D. atriotua

' D. hamiltonii D. longiapatuus Melocanna bambuaoidea

M, bambuaoidea

Ochlundia travancoriea Oxytenonthera ailiata nigra Phylloataahya edulia

V. makinoi P. nigra P. reticulata

Sohizoatachyum lumampao ,

4.05 4.05 -

5.0 5.5

••.2

6.75 5.5 4.75

3.98

9.0

6.Ü 3.34

--

3.66

-

Millimetres

0.67 0.67 -

1.0 1.0

0.58

1.5 1.0 1.0

0.80

1.0

1.0 0.42

--

0.21

-

2.73 .2.73

-2.98 3.6 (India) 2.23 (Japan) 3.36 3.50 2.72 (India) 1.89 (Japan) 4.03

3.55 1.37 (Japan)

--

1.56 (Japan)

2.42 (Philippines )

Percentage

Sinocalamue lateflorue TeinoBtaohyum dulloa

57.6 57.6

-64.4 60.8

63.3 63.0 62.3

bl.8

66.7

30.1 30.1

-24.2 32.2

26.2 24.5 24.1

26.9

27.1

19.6 19.6

-18.4 19.6

21.5 19.5 15.1

17.8

17.4

6.0 1.0 3.63 64.6 23.8 18.1

Uit: F.A.O., 1973.

1-16

Fig. ' . Propagation of bamboos of Group I by means of culm segments with buds but no branches; Bambusa vulgaris var. oitiata. Design developed for an experimental planting at Tcleman, Aha Verapaz, Guatemala, showing the orientation given the cutting as it is planted. Meter-long basal cuts of culms, in six age groups, were used for determining the effect of age of culm material on yield of rooted plants. |

From McCLURE, 1966,

FIG. 2 «PREFEIHIED METHODS OF PLANTINO BAMBOO. MONOPODIA!.: 1 ) Longer length of culm with rhizome

attached. 2 ) Shorter length of culm with rhizome attached. 3 ) A length of rhizome alone. SVMI-ODIAL: • ) Longer or shorter lenghts of culm and rhizome. 5 ) Horizontal length of culm. 6 ) Slanted length of culm.

From AUSTIN ot a l . , 1970.

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Fig 3. a. Scheme of branohing of a culm (1. normal branching, 2 and 3 rare occuring 'branchings) | b.up to and including g.Appearance of different maintained standsj b. strongly over-exploited, c. normally-thinned, d. thinned too sparse,e. elevated clump, f. overcrowded clump, and g. because of shade etiolated clump.

Prom HILDEBHAHD, 1954.

I

Appendix II

Contents Page

1. Introduction 1 1.1 The distribution of Imperata spp. 1 1.2 Botanical description 1 1.3 Uses of Imperata oylindrioa 1

1.4 Ecology 1

2. Biological methods of Imperata eradication 2

3. Mechanical methods of Imperata eradication 4

4. Eradication of Imperata by chemical methods 4

Literature . 6

II-l

Appendix II: THE CONTROL OF IMPERATA SPP.

1 Introduction

1.1 The distribution of Imperata sgg.

The genus Imperata consists of a number of species, of which Imperata oylindrica is het most notorious one. It is a paleotropical species occuring in Africa and Asia, mainly in the humid tropical lowlands, although it is reported to occur up to 2700 m above sealevel.

1.2 Botanical description

According to COSTER (19321 Imperata oylindrica (Beauv.) is a perennial grass with a height of 20 to 230 cm (on favourable sites)., and with long rhizomes. These rhizomes consist of joints of 0,5-3 cm length. At the nods, one or more roots sprout, growing down to 80-150 cm. Rhizomes are found at a depth of 15-40 cm. Buds are found at the knods also; when sprouting, a part goes up to form the superficial portions, another part forms new rhizomes, thus extending the root system. Five varieties of Imperata oylindrica are distinguished, of which Imperata oylindrica var. major has the widest distribution, and also causes the most trouble, particularly in Southeast Asia. Local names for this variety are: alang-alang (Indonesia), lalang (Malaysia), cogon (Philippines), illak (Sri Lanka), and tranh (Indochina).

1.3 Uses of Imperata oylindrica

Generally it is considered to be a worthless grass species. In Vietnam mats made from this grass are used for roofing (CHEVALIER, 1952). Further, it can serve as an isolation material; however it is very inflammable. Young shoots can be eaten by stock, a reason for the practice of burning Imperata grasslands. Further, it became clear from experiments in Malaysia (TEMPANY, 1951) that it gives a long-fibered pulp with excellent felting properties. It also produces a strong, opaque paper which does not shrink while drying. The time of harvesting of the grass is important for pulping: it should be done before flowering; also, the ratio between dead and living material is important. Yields of 2.5-3.7 tons of pulp per ha are reported from Malaysia. As fast-growing tree species can have an annual yield of 7.5-17.5 tons of pulp per ha (MITCHELL, 1964), it is not likely that Imperata will replace trees as a pulp supplier. It might, however, supply factories consuming bamboo or rice-straw, and provide an additional resource in case of a temporary shortage in the supply of raw materials. In the future Imperata grass possibly might become more important as a pulp supplier, in view of the expected shortages of paper.

1.4 Ecology

Vegetative spread of Imperata can be very rapid; the species is very tenacious and very difficult to eradicate. It is a ready colonizer of cleared terrains where it usually forms the major component of the vegetation. It forms vast fields with scattered groups of trees or shrubs. These fields are the final stage in a regressive succession series. They are particularly found on abandoned shifting cultivation sites, as a result of too short fallow periods and periodical burning (see also main report III.3.). In addition, the danger of an Imperata invasion exists in permanent agriculture; thus frequent weeding is required. The strong competitive power of Imperata oylindrica comes from the following factors:

It has strong underground rhizomes which form so extensive a network at 15-40 cm below the surface that the roots of few plants can compete with it (COSTER, 1932);

II-2

The rhizomes form a reservoir of food which is of the utmost importance to the plant; it enables the plant to survive fire as well as digging, unless every piece of rhizome is extracted; The underground stems are provided with sharp, hard points which, in the course of their growth, penetrate the major roots of other plants. This mechanical damage was reported among coconut, rubber and pineapple (TEMPANY, 9151): Strong competition for plant nutrients and water; The great ecological amplitude; it is found on periodically wet as well as on periodically very dry sites, although in the latter case growth is less luxuriant ; Vegetative as well as generative propagation is quick and easy; Many chemicals kill the above ground parts, but not the roots and rhizomes; There are indications that Irrtperata exudes some substance that is toxic to other plants, particularly at the transition of rhizome and root (allopathy); the effect increases with decreasing pH (EUSSEN and WIRHARDJA, 1973).

Several methods exist to make Imperata fields productive again which should be tried. They can be mechanical, chemical, or biological. These methods can also be employed in combination.

2 Biological methods of Imperata eradication

Imperata cylindrica requires full light exposure for growth, and dies when shaded by other plants. This is essentially a reafforestation problem; biological methods aim to find plants which can establish themselves despite the competition of the grass and can provide the necessary shade. One way to reach this is natural succession. This process, however, takes a long time because of the persistence of Imperata; it continues its possession of the ground as long as it is burnt at regular intervals. Therefore, exclusion of fire for a long time is essential to make possible the establishment and development of seedlings of trees and shrubs. Good results were obtained by taking fire-preventive measures in Malaysia. Melaetoma malabathricum appeared forming islands of shade causing the Imperata to die off. Other larger species appeared, such as Mallotus spp. and Vitex pubescens. Small patches of Imperata took some five years for complete suppression, but extensive areas take longer and the fire danger is greater (STRUGNELL, 1934). A similar situation is found in South Vietnam, in the lowland on basalt (see main report III.3.). Imperata cylindrica and Eupaiorium odoratum are found together at the beginning of a progressive succession. Eupatorium odoratum has a deep rooting system, is somewhat fire-resistant, and sprouts rapidly after burning. After a fire some shading out of Imperata by Eupatorium may taken place, as the latter develops slightly more quickly; after repeated burning, however, Imperata cylindri becomes predominant. When fire is excluded, favourable conditions are created for species such as Grewia spp., Mallotus spp., Tremia spp., and others. Via other stages, finally, the forest may reestablish itself.

This progressive succession can be accelerated and favoured by the planting of tree or shrub species which are able to establish on the Imperata fields. New trees and shrubs naturally occurring during the various stages of the progressive succession can be used. For instance, in Malaysia, succesful planting of Vitex pubescens was carried out in the Melastoma malabathricum stage. Stumps (60 cm stem and 15 cm root length) of 6 months to one-year-old nursery stock were plantet in rainy weather. A suitable distance was 3.6 m between the rows and 0.9 to 1.8 m in the rows (1500-3000 plants/ha). A distance of 1.8 m was effective, but a distance of 0.9 m covers Imperata more quickly. Digging and clearing of fire linei

II-3

was considered, but it came out that no further attention was needed. Under favourable conditions, seedlings reached a height of 3 m in one year. It took 4-5 years to control the Imperata (STRUGNELL, 1934). Albizzia moluccana was not as effective as Vitex, although useful results were obtained, as Albizzia enabled the establishment of other plants which completed the process. A disadvantage of these so-called short-lived species is their low economic value, except for fuelwood (and in the future possibly for pulpwood). Therefore, in the selection of species suited to control Imperata, species are sought which have, next to suppressing quatities, also some economic value. Important characteristics in this respect are:

deep rooting capacities; fire resistance; wide-spread, dense crown; resistance of roots to penetration by rhizomes of Imperata; fast growth,

(see also Appendix IV) In the Phillippines, Sri Lanka, and the Indonesian island of Flores, the planting of Leueaena leuoocephala proved succesful. This species is suited to somewhat dry regions (3-4 dry months), it delivers light construction wood, and is of special importance as a fuelwood supplier. Following the burning of the Imperata field, the seeds of Leueaena were broadcasted. In this way the hazard of seed damage by rodents was reduced. Besides broadcasting seed, also spot and line sowing and planting were applied. A spot of 2 m or a strip of 2 m wide was clearer for sowing. Sowing was done from an airplane, but this was unsuccessful. Possibly burning before sowing gives better results. No problems were met during planting when the grass was no longer than 60-90 cm (WEIDELT et al., 1975). When higher, it first had to be cleared. For every plant a spot of 50 cm diameter was cleared of Imperata, including the rhizomes. Large stock was used, and sometimes manuring was done. Weeding and filling in was carried out 3-4 months after planting, and afterwards twice a year, until the plants had outdistanced the Imperata. Line planting was mostly done at a spacing of 2x2 m, but also at 3x1.5 m. In Malaysia, sowing is usually not advised, although good results are obtained with species such as Albizzia faloata, Acacia auriauliformie, Anacardium occidental and Styrax benzoin (BARNARD, 1954).

In Vietnam in the region of Xuan Loc - Ba Ria good results were obtained with the sowing of Mimosa invisa in Imperata vegetation (DARON, 1952). Just before the wet season, the Mimosa seed was broadcasted amongst the grass at the rate of 20-40 kg seed/ha. After that, the terrain was burned, thereby favouring the germination of Mimosa invisa. From the beginning of the rains it develops well. If fruits abundantly before dying in the dry season. The cycle starts again by itself in the next year after burning. After 4 to 5 years the Mimosa has strongly weakened, although not completely eliminated the Imperata. In addition, the soil is strongly improved by the Leguminose Mimosa invisa. Another specie advised for the control of Imperata is Tithonia diveraifolia (CHEVALIER, 1952). In Malaysia planting Albizzia falcata as stumps is considered most promising for accelerating natural succession. In addition, species worth further trial are Schima noronhae and Acacia auriauliformie, both as tubed seedlings. Gmelina arborea is uncertain in its effect, but may be successful in cultivated patches on moist sites and good soil (BARNARD, 1954). In the Philippines the most promising species are: Pinus kesiya, Tectona grandis, Pterocarpus indicus, Vitex parviflora, Lagerstroemia speciosa, Swietenia macrophylla, Casuarina equisetifolia, Aleurites moluccana and Cassia fistula. Possible further suitable species are: Cassia 8pectabili8, Gliricidia sepium, Peltophorum ineme, Spathodea campanulata, and Cedrela odorata (SAN BUENAVENTURA, 1958). Some of the above species were tried in Malaysia but proved not successful: Mimosa invisa (the seeds germinated well but few survived after one year, and none after 3 years). Casuarina equisetifolia seedlings were often suppressed by Melaetoma (BARNARD, 1954).

II-4

Cover crops can be used as a smother crop, and are sown amongst the grass. In Zanzibar (Tanzania) good results were obtained with Pueraria phaseoloidea ; in Malaysia, Centrosema pubeecens had a similar effect (TEMPANY, 19511.

3 Mechanical methods of Imperata eradication

These methods aim at the destruction of the rhizomes. Chemical and/or biological methods may be most effective. It is done during site preparation as well as during maintenance of the culture. A number of methods of mechanical eradicatioi will be mentioned in short. The selection of a suitable method will largely depend upon local conditions; it has to be determined by experiments. Some important factors in this respect are the time and frequency of the cultivation, depth of cultivation, type of machinery, eventual combination with other methods.

Regular mowing or grazing of the Imperata, by which the rhizomes become exhausted in time. Deep cultivation with a fork or a hoe and picking out all rhizomes by hand. This method is successful on light soils only, as on heavier soils the rhizomes stick into the clods and sprout again. Often this method is carried out in the dry season in order to obtain a good result. The rhizomes are dried in the sun. This method is very labour-intensive (COSTER, 1932). In Malaysia successful eradication was obtained with disc-ploughing down to 25 cm depth, disc-harrowing down to 5 cm depth, and rotary-cultivators. There was an indication that ploughing was more consistently effective than disc-harrowing or rotary cultivation. A final cultivation with a straight-line cultivator significantly reduced the amount of surviving Imperata. Trials in which mechanical control was combined with spraying sodium arsenite showed that two sprayings at weekly intervals followed by four rotary cultivations at two-weekly intervals were most effective (HARTLEY, 19<+9).. These experimem were carried out on exposed Imperata fields. MARTIN (1975) reports that 6-8 times of disc-ploughing in the dry season at intervals of 8-10 days gave good results. Disc-ploughing was stopped when th< fresh rhizome weight per m was below 30-40 grams. Often covercrops are sown after mechanical treatment in order to avoid humus oxidation, structural degradation, erosion or renewed invasion by Imperata grass on the site. This sowing can be done before or at the same time of planting of tree species or food or tree crops. In Indonesia, Indigofera gaXagoiàes is planted in between the rows of trees. Other covercrops are: Aaacia villosa, Leueaena leucocephala, Tephroaia vogelii, Centrosema pubeacena, Calopogonium mucunoides, Pueraria phaaeoloides , Phsophocarpua paluetri8, Salvia spp., and Ageratum spp. (ALPHEN DE VEER S VINK, 1952). On poor soils sometimes manuring with woodashes or phosphate is applied in order to get a quick covering of the soil. Good results have been obtained with Tephroaia Candida in Nigeria, Crotalaria striata and C. utilis in Ghana Pueraria thunbevgiana in Kenya and Crotalaria juncea in India (VAYSSIERE, 1952). Finally, another method to be mentioned is the flooding of Imperata fields.

i+ Eradication of Imperata by chemical methods

In practice, chemicals are particularly used in the eradication of Imperata especially in plantations. The following distinctions can be made: a) Chemical control before planting of trees or cultivated plants. The chemical

means can be a little selective in this case, but they should not be too persistent. The best effect is gained by spraying.

b) Application of chemicals in plantations. The chemical used must be rather selective, or the trees or cultivated plants must be fairly developed, or spraying has to be done very carefully (directed, and without dispersing). Again, the persistence within the soil plays a part. The persistence varies from one area to another. In Ivory Coast, Dalapon persists for 1-2 months i

II-5

light, sandy soils and 4-6 months in clayey soils. Also the climate has an important influence on the persistence within the soil. The sensitivity of the species varies too. Coconut palms proved rather sensitive to Dalapon. Spraying was advised 1-6 months before planting in this case (COOMANS, 1976). In Indonesia, rubber proved to be insensitive to Dalapon. Following planting, three sprayings at one month intervals were applied, combined with a shading tree Gliricidia maculata (SUKATAATMADJA & SIREGAR, 1971). Particularly in the first years of the plantations, the frequent control of Imperata is required, not only because of the strong competing capacity of Imperata, but also because of the increased fire hazard and the favourable environment created by the grass for rodents which can damage the young plants. Since chemical methods alone are often too expensive, they are combined with mechanical methods. The success of chemical control very much depends on local conditions. By means of experiments it should be determined which chemical, in which concentration and frequency, is most effective for control of Imperata in a certain plantation. Dalapon (1.5% solution in water, 15,-20 kg/ha) is often applied and is especiall used for the control of grasses. Other chemicals which are frequently applied are: Paraquat, Glyphosphate, Simazine (in high concentrations), T.C.A., chlorates, and arsenites. 2,4-D and 2,4,5-T kill the above-ground parts of Imperata, but not the roots and rhizomes.

II-6

Literature

o Alphen de Veer, E.J. & A.P.A. Vink (1952). Bestrijding van alang met chemische

en mechanische middelen. (Control of Imperata with chemical and mechanical methods). Tectona 42, 1952.

Barnard, R.C. (1954). The control of lalang (Imperata arundinaaea, var. major) by fire protection and planting. Malayan Forester. Vol. XVII.

Coomans, P. (1976). Chemical control of Imperata. Oléagineux (1976), 31, (3). Instit. Rech, huiles oléagineux, station de la Ml, Ivory Coast. From: Selectee References to Imperata cylindrica '54-'65. Oxford '74. Annotated bibliography, weed research organisation. Agric. research council no. 75.

Coster, Ch. (1932). Enige waarnemingen omtrent groei en bestrijding van alang (Imperata cylindrica Beauv.). (Some observations of growth and control of Imperata). Tectona 25, 1932.

Eussen, J.H.H. & S. Wirjahardja (1973). Studies of an alang (Imperata cylindrica L. Beauv.) vegetation. Biotrop, Bogor, Indonesia.

Hartley, C.W.S. (1949). An experiment on mechanical methods of lalang eradication. Mai. Agric. Journ. 1949 (32).

Martin, G. (1975). Land preparation of Imperata savannah or grass pasture. Oléagineux (1975) 30 (11). From: Selected references to Imperata cylindrica '54-*65, Oxford, 1974.

Mitchell, B.A. (1964). Periodical cropping of Imperata cylindrica for paper pulp. Mai For. 1964.

San Buenaventura, P. (1958). Reforestation of Imperata waste lands in the Philippines. The Philippine journal of forestry no. 14, 1958.

Strugnell, E.J. (1934). Lalang and its eradication. Mai.„For. Vol. III. Sukartaatmadja, K. & 0. Siregar (1971). Control of alang by a combination of

shading with Gliriaidia maculata and dalapon application. Proceed, le Indon. weed science conf. Bogor, 1971. From: Selected references to Imperata cylindrica. '54-'56, Oxford, 1974.

Tempany, H.A. (1951). Imperata grass, a major menace in the wet tropics. World crops, April, 1951.

Vayssière, P. (1952). Les mauvaises herbes en Indo-Malaisie. Revue internationale de Botanique Appliquée et d'Agriculture Tropicale; 1957 (32).

Weidelt, H.J. et al. (1975). Manual of reforestation and erosion control for the Philippines.

Williams, C.N. (1960). Sopubia ramoea, a perennating parasite on the roots of Imperata cylindrica. J. W. Afr. Sei. Ass., 1960, Univ. of Ibadan, Nigeria. From: Selected references to the biology and control of Imperata cylindrica, 1954-1965.

Appendix III

Contents

Page

1. Introduction 1

2. Erosion 1 2.1 Introduction 1 2.2 Erosion research 3 2.3 Erosion control and soil protection 4

2.3.1 Gully erosion 4 2.3.2 Sheet and rill erosion 5

2.4 Erosion in South Vietnam 6 3. Social and economical aspects 7

3.1 Modernizing shifting cultivation 7 3.2 Afforestation f 7

4. Silvicultural aspects of afforestation on eroded soils 9 4.1 Site preparation 9 4.2 Cover crops 10 4.3 Choice of tree species 10

Literature 11

III-l

Appendix II: EROSION CONTROL

1 Introduction

The occurrence of man-made or accelerated erosion is a problem in most tropical and subtropical regions. In Vietnam before the Second Indochina War, however, it seemed to have been of minor importance; most regions with highly erodible soils were thinly populated (main report Ch. III). The various means of environmental assault used during the war, however, seriously disturbed the protective cover of many of these soils or completely removed it, thus exposing them to erosive agents (main report Ch. IV). This resulted in large-scale soil erosion and soil degradation, which is locally very serious. Substantial erosion damage resulted from Rome-ploughing, high-explosive munitions, and the use of herbicides. In addition, an indirect effect of that war was the concentration of many people in a relatively small areas, which lead to nearly complete deforestation of these areas. Flooding hazard markedly increased, as the hydrologically protective and stabilizing influence of vegetation was lost. In the, following section, general aspects of erosion are dealt with; followed by methods of erosion control and soil protection; and finally a discussion on methods of establishment and maintenance of plantations on eroded sites. The following section of the report is drawn from the literature review, "Afforestation of Eroded Soil in Java (Indonesia)" prepared by a study team of students in Tropical Silviculture (1973). Only parts of this review are taken, and adaptions are made to fit the Vietnamese situation. For a full account on erosion control and protective measures, see AL' BENSKII & NIKITIN (1956), BENNETT (1939), HUDSON (1971), WEIDELT et al. (1975). Species suitable for eroded sites in Vietnam can be selected from a list of more than 100 species in Appendix IV.

2 Erosion

2.1 Introduction

Erosion is a process by which soil and rock particles are carried, rolled, or washed away. The main agents which detach and transport the particles are water and wind. Two types of erosion may be distinguished: geological erosion, and accelerated erosion. Geological erosion (normal or natural erosion) results from the forces of nature; it is fundamental to the formation of alluvial soils and sedimentary rocks. The present topography has been caused by these forms of erosion slowly taking place over many centuries. If this process of geological erosion is speeded up by human activities, then it is referred to as man-made or accelerated erosion. This type of erosion has, in many cases, led to a progressive deterioration of the soil. Two forms of erosion can be distinguished: water erosion and wind erosion. In the humid tropics, only water erosion is of significance; therefore, in the following report only this form of erosion will be discussed. The occurrence of erosion is influenced by the following factors: a) climate b) soil c) topography d) vegetation e) anthropological influences

a) Climate: The most important climatic characteristic influencing water erosion is rainfall. The splashing of raindrops provides an important part of the energy used during all phases of erosion: breaking down soil aggregates, splashing them in the air, causing turbulence in surface run-off, and scouring and carrying away soil particles. The erosivity of rainfall (the potential

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ability of rain to cause erosion! is conditioned by its intensity, duration, and distribution. In the tropics 60% of the rain falls at intensities of less than 25 mm/hour; the remaining 40% contributes to soil erosion. In temperate regions 95% of rain falls at low intensities and only 5% is heavy enough to cause erosion.

b) Soil: On a given site, soil structure, stability, and cohesion characteristics of the soil will determine the ration between the amount of infiltrating water and the amount of run-off water, and the erodibility of the soil. The stability of soil is largely dependent on its humus content, the clay/ loam ratio, and (sometimes) the occurrence of ses-quioxides. Humic and argillic colloids cement sandy and silty particles, while organic matter favours biological activity, thus improving porosity and aggregation. The permeability of a soil depends on its texture, structure, humus content, the type of clay mineral and the nature of bases at the complex may determine its flocculation (Ca, Mg) or dispersion (Na). As high temperatures lead to increased oxidation of humus, deforestation results in higher erodibility of the soils.

c) Topography : The steeper the slope, the greater the erosion; since there is more splash downhill, there will be more run-off and it will flow faster. The extent of erosion rises rapidly as the slope increases. In addition, the length of a slope is important; on a long slope the amount of surface run-off builds up more and reaches a higher velocity.

d) Vegetation: Forest, whether dry or humid, is the form of vegetation which best guarantees conservation of both soil and water. Undergrowth plays a vital role since it holds and protects the soil while larger trees absorb the kinetic energy of the rain-drops. When the undergrowth is absent, severe run-off and erosion may occur (as for instance is reported to occur under well developed stands of Eucalyptus, Teak, Pinus). Once grassland is established, it appears to hold and protect the'soil as well as a forest plus undergrowth, but its protective role is more pronounced as its coverage of the soil is denser. Erosion is almost nil when soil is 100% covered, even on steep slopes. Vegetation not only protects with its above-ground parts, but also with its subsurface parts: granulation is improved by roots and porosity is increased in upper and lower parts of the soil. Further vegetation can deliver litter which protects the soil against the impact of rainfall, slows down the runoff, and delivers humus. Lastly, vegetation - especially forest - has a large influence on the water balance of an area, not only by interception but also by transpiration. Only a part of the rain falling in a forested catchment area is gradually released to the rivers flowing below. In a catchment area with a grass cover, poor forest cover, or with completely bare land, however, the major part of the falling rain directly flows into the rivers as run-off.

e) Anthropological influences : During the last decades, the population in tropic countries had increased considerably. In order to grow enough food, in many cases it has become necessary to reclaim land. Often these lands were margina and had to be abandoned after a few years of cultivation. In other cases extensive forms of agriculture (e.g. shifting cultivation) were intensified. Both processes have led to soil deterioration and erosion.

Water erosion can be classified according to the following system: A. Erosion caused the direct impact of rainfall, and by run-off.

A.l. Splash-erosion: breaking down soil aggregates and detaching soil partiel On slopes of more than 50%, particles are splashed downhill.

A.2. Sheet-erosion: washing of the surface soil by a laminar flow of water. Since, however, run-off seldom occurs in flat sheets, HUDSON (1971) proposes to banish this definition.

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A.3. Rill-erosion: localized small washes in defined channels which are small enough to be eliminated by normal agricultural methods. Sedimentation of eroded material takes place at the foot of the slope.

A.t. Gully-erosion: localized washes in large channels which are so large and well-established that they cannot be crossed by farm implements. Sedimentation of eroded material takes place in downstream areas.

B. Earth movements

B.l. Lahars (mostly on volcanic soils) B.2. Landslides B.3. Creepsoils B.4. Underground erosion (mostly on calcareous soils) B.5. Streambank erosion (undercutting of riverbanks).

All these forms of erosion not only form a problem because of degradation of the soil (which reduces its ability to grow crops) but also because they cause sedimentation of the eroded particles. The distance over which the soil particles are transported depends on the size, shape, and concentration of the material; and the velocity of the water. If the velocity of the water decreases, first the larger particles and later the small ones sediment; this may be within a basin on arable lands or outside the basin. This sediment may silt drainage- and irrigation ditches or canals and reservoirs, which has serious consequences for their water retention capacity. This decrease in water retention capacity may lead to inundatie in downstream areas. In addition, serious erosion is often associated with large fluctations in waterflow and flash floods.

2.2 Erosion_research

The purpose of erosion research is to collect factual information about rates and quantities of erosion in order that protective measures can- be taken. Erosion research may take the form or reconnaissance studies, field experiments, and sometimes laboratory experiments. The reconnaissance survey establishes the order of magnitude of erosion on differen soils. This survey includes measurements of existing erosion (measurements of changes in surface level and of gullies), and determination of the topography, soil characteristics, soil profile and vegetation in an area (in relation to erosion). Field experiments are carried out to get accurate data about the different factors influencing the rate and amount of erosion, as well as to test erosion-control measures. Quantitative evaluation of erosion can most accurately be obtained from permanent plots. The size of these plots depends upon the objective of the experimei and the nature of the data collection. The smallest plot (micro-plot) is 1-2 m . Accuracy is not great, but it is sufficient to establish the order of magnitude of the difference in erosion between simple treatments, or to get an idea of the relative erodibility of different soils.

To measure surface run-off larger plots are required so that the cumulative effect of run-off down a slope is reproduced. In the USA the standard plot size is 22x1.8 r (area 40.5 m ). On the basis of a number of such plots, the erosion effect of cropping practices has been quantified under the conditions in the U.S. in the Universal Soil-Loss Equation (formula of Wischmeier). To calculate the soil loss in tons per unit of area, the erosivity of rain, and the soil erodibility must be known. Furthermore, the following comparative ratios must be known: a. the soil loss from a particular parcel compared to a field of specified length. b. the soil loss " " " " " " a field of specified slope, c. the soil loss " " " " " " a field under a standard

treatment, d. the soil loss " " " " " " a field with no conservatior

practice. Where field-scale farming and forestry operations are an essential part of erosion research, larger plots of 0.02 ha and upwards are used. Sometimes small watersheds are used for measurements, also.

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The plot boundaries should prevent the passage of run-off from the surrounding area into or out of the plot both above the ground and below. At the bottom edge of the plot, the water and soil are collected in a sunken trough and are lead to storage tanks. When larger plots are used, they require some -mechanical division of the run-off; for example, the run-off can be measured by a -measuring flume at the outlet of the plot. With these methods both run-off and erosion can be measured and related to crop management and conservation practices.

2.3 Erosion_control and soil protection

Erosion and soil degradation usually are the result of adverse agricultural or forestry methods. Soil conservation and erosion control should be based on a modification of these methods and the application of systems which protect the soil, and which maintain or increase the productivity of the soil. As mentioned before, erosion may take place in several forms: the most important being splash and sheet rill-erosion mostly taking place in the upper watershed (water-catchment) and gully erosion mostly taking place in the lower watershed.

2.3.1 Gully erosion

The basic cause of gully erosion is either an increase in the amount of flood run-off in a channel, or a decrease in the ability of the channel to carry the flood. Therefore, the methods used to control this form of erosion consist of one or more of the following:

increase water retention capacity in the catchment area; divert the run-off from the gully; safely convey the run-off through the gully.

These methods can be brought about by vegetative controls or a combination of vegetative and engineering controls.

Vegetative controls

The purpose of vegetation in erosion control is twofold. Firstly it provides the soil with physical protection against scour. Secondly, it slows down the velocity of flow by increasing the hydraulic resistance of the channel (thereby greatly reducing the scouring and abrading of the flood). Plants to be used for gully control should grown vigorously in the bed of the gully (which is usually almost sterile with no structure, no organic matter, no available plant nutrients and low moisture-holding capacity)., give good ground cover, have an extensive root-system, and a spreading, creeping habit. Local plant species usually give better results than exotic species, especially after application of fertilizers. Preferably no trees or shrubs are to be planted in the very waterway as this would prevent good water passage.

Vegetative control of gullies may take several forms depending on the size of the gullies. Small gullies can sometimes be filled in; they can also be stabilized with grasses, vines or shrubs. In other cases it is necessary to employ artificiaJ methods such as seeding or planting, fertilizing, mulching and anchoring the soil and plants. In the humid tropics, in order to establish vegetation, protection from grazing animals may be the only necessary control. With larger gullies the run-off often has to be diverted from the gully head before taking vegetative control measures. After the vegetation has become taking vegetative control measures. After the vegetation has become established, large gullies can often be used as vegetated waterways for draining water. In addition to these measures, larger gullies are often protected by tree planting. Trees are planted along the gully banks to protect undermined gully sides, on steep gully slopes to protect them, and on the flat upper flanks of the gully to spread the run-off and to protect the slope of the gully. If trees are used as a vegetat control measure, several rows are planted (otherwise vortexes may be formed in the run-off, thus increasing the danger of erosion1.

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Engineering controls

It frequently happens that the establishment of vegetation is difficult becai the newly planted material gets swept away, or because there is no soil for the plants to grow in. .In either of these cases structures may be constructed to prov: protection in order to get the vegetation established. In other cases, structures may be necessary to provide protection for those critical sections in the channel which cannot be adequately protected by vegetative measures. These engineering structures may consist of diversion ditches or terraces, temporary dams or permam dams. Preferably they should, however, be used as little as possible since they are expensive and require a lot of maintenance.

Diversion ditches or terraces are used to divert the run-off from the head of a gully before control measures are installed within the gully. It is essential that diversion ditches are large enough to carry all the run-off from the contributing drainage area during periods of maximum rainfall. Furthermore, the gradient and dimensions of the channel should allow the run-off to move through the ditch at non-erosive velocities. Temporary dams have two uses:

1. to collect enough soil and water to ensure the eventual growth of protective vegetation, and

2. to check head or channel erosion until sufficient stabilizing vegetation can be established.

Structures do not need to be watertight; they may consist of wire bolsters, nettin dams, brushwood dams, log dams, or brick weirs. In some cases gully erosion can only be controlled by building permanent structure These permanent structures are frequently necessary in gullies with large contributing watersheds and in gullies that must be retained as permanent waterway These structures need not to be expensive, but it is essential that they are thoroughly and carefully constructed. The structures may consist of masondry dams or gabions. Well-constructed masonry and brickwood resist compression satisfactory but the main difficulty of these rigid structures is that they cannot be adapted when changes occur in the soil surrounding them or supporting them. Gabions (consisting of rectangular baskets of wire netting filled with stones) overcome this problem; they are sufficiently flexible to adjust to settlement resulting froi scouring of their foundations without any loss of strength.

2.3.2 Sheet and rill erosion

To control sheet/rill erosion generally, it is necessary to keep the soil under effective vegetative cover for as long as possible. If this control is not sufficient, one has to control run-off by mechanical means. Both physical (climate slope, rodibility) and economical factors determined which vegetative measures are taken. To determine the most suitable use and vegetation for a given area (forest, grazing lands, agricultural lands), it is necessary to classify the land according to its suitability. Most erosion classification systems stem from the Land Capability Classification of the U.S. Soil Conservation Service, but they can be more or less modified according to local circumstances. In humid tropical areas with an average rainfall of over 1,800 m, the following classification is often used (this classification is primarily based on slope gradient, but there may be modifications depending on other factors):

Slope > 70% (35 ) : No agriculture and pasture possible - natural forest should be preserved - some wood exploitation is permitte - special attention for the construction of roads.

Slope 50-70% (25-35 ) : Forests should be maintained - exploitation possible but no clearfelling of large areas is permitted.

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Slope 30-50% (17-25 ) : Possible land-use depending on soil erodibility - if n used as forest land, preference should be given to perennial crops (tea, coffee1 or pasture - soil protec measures, both vegetative and mechanical, are necessar too steep for annual agricultural crops except rice on sawahs.

Slope 15-30% (8.5-17 1 : Possibilities for agriculture and pasture - shifting cultivation, sawahs, annual and perennial crops - soil protection measures, both vegetative and mechanical, a necessary.

Slope 5-15% (3-9 1 : Good possibilities for agriculture and pasture - shift cultivation on poor soils - protection measures such é stripcropping and crop rotation should be taken on soi with high erodibility.

Slope < 5% (3 ). : No (or slight 1 limitations.

Some of the main vegetative control measures are the following: Silvicultural measures can consist of large-scale afforestations or the plai of protective tree rows. In order to give optimal control, forests should bi sufficiently close. If natural regeneration is not sufficient, enrichment hi to be applied. Measures on pastures and rangeland can consist of regulating the number and kind of livestock, providing forage for the livestock, re-seeding with gras and forage crops. Agricultural measures can consist of crop rotation (short rotations are preferable in the tropics), stripcropping, use of cover crops, mulching, an fertilizing.

Some simple mechanical measures to control sheet/rill erosion are several forms contour tillage, tied ridging, and contour ditches. Terracing is also a very effective measure, but in tropical regions it is often too expensive and big ear moving machinery is often not available in these areas. Landslides: Even if silvicultural measures have been taken, it is still possible that landslides occur. A good possibility for control seems to be the planting of bamboo (see Appendix chapter 6) on susceptible sites.

From observations by CASTAGNOL (1952), (SCHMID, 19741 has written that: 1) The soil under woodland is poorly protected against the impact of rainfall

resulting in structural degradation of the soil and sheet/rill erosion, ev< on sites with a relatively flat relief.

2) In mountainous regions, landslides are a common feature on forested slopes with the Acrisols which cover a large part of the mountains. Large masses < soil slip down, often triggered by the fall of a tree(s). For instance, numerous and very spectacular landslides were reported from the mountains after a typhoon in 1952.

3) In prairie-steppes on deep basaltic soils, gully-erosion is locally (e.g. Haut Chhlong) observed.

According to SCHMID wind-erosion is neglectable; however, some dust whirls can observed in the dry season on plateaus (e.g. Plei Kul, especially after burning for shifting cultivation. Generally, erosion is most active in areas with granite, and is less evident in basalt areas. It seems that before the war, erosion and soil degradation were problems of mill importance ; they were found where shifting cultivation and its attendent burnir had been too intensive. However, population density was (and is) low in these a War activities, however, led to large-scale erosion and soil degradation as vegetative destruction was accomplished over large areas by different technique

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and weapons. Complete deforestation or serious damage to forests were the result The most seriously hit was the Highland of the Me Kong. The soils in this regior (gray brown podzolic soils, red and yellow podzolic soils and low humic gley soils, all Acrisols) are very susceptible to erosion and liable to degradation. Fortunately the major part of this area is very gently undulating, but still she rill erosion and soil degradation resulted from war activities, and also gully erosion may have occurred especially on bulldozed parts.

Other severe erosion resulted from bombing and war actions in hilly and mountain land. Bombing triggered landslides and gully erosion. Indirectly the concentration of people in strategic hamlets also resulted in soi degradation and erosion, as in the neighbourhood of these hamlets the pressure o the land increased, resulting in an increasing deforestation for shifting cultivation.

3 Social and economical aspects

3.1 Modernizing_shifting cultivation

In the inland forest areas, shifting cultivation is the principal form of land use. It is a rational form of land use as long as the fallow period is ampl' With increasing population, shifting cultivation has -many disadvantages which ca; be summarized as follows:

continuation of shifting cultivation -may lead to a very dangerous situation with regard to accelerated erosion and disruption of the water regime ; there exists an ever-widening gap between the standard of living of people living from shifting cultivation and the rest of the population.

Therefore, it is essential to seek suitable solutions which will develop more rational forms of land utilization, depending on agricultural suitability and hydrological aspects. This may be done by regulation of shifting-cultivation, introduction of permanent agriculture, and afforestation (which may be done by means of an agrisilvicultural system)..

Regulation of shiftingcultivation

By localizing shifting cultivation to certain areas with soils of low erodibility, land with high erodibility can be reserved for protective forestry. This may be done gradually by increasing the forested area in relation to the intensification of agriculture. In order to regulate shifting cultivation, good extension service is essential. Special emphasis should be placed on information about good burning practices, sc conservation measures, crop rotation, and the necessity of a fallow period of at least 12 years.

Introduction of permanent agriculture

On certain suitable soils, shifting cultivation may be replaced by permanent agriculture. Efficient extension and credit facilities are needed in order to acquaint the farmers with such practices as intensification of growing crops, use of green manure and fertilizers, and engineering practices such as terracing, drainage, and irrigation.

3•2 Aff2ïêlî§îi°S On mountains where the protective forests have been cut, afforestation is

necessary. The advantages of planting protective forests are: a) reducing erosion b) reducing sedimentation on lower agricultural areas, ci producing a regular waterflow in rivers, which gives better opportunities for irrigation, generating electricity, winning drinking-water and assainering, and dj reducing the silting-up of reservoirs.

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Thus recurrent costs caused by dredging rivers and irrigation canals, and restori damage from flash floods, are reduced. The restoration of protective forests benefits large communities and forms a permanent contribution to a higher nationa and regional income. Afforestation and other technical works associated with it stimulate employment. Several kinds of areas which are unsuitable for agriculture because of impoverishment, are still suitable for forestry. There are several tree species which are suitable for growing on impoverished soils when proper silvicultural techniques are applied.

Afforestation will lead to ample supply of wood for the local people. Shortage of timber may arise with increasing population, especially fuelwood, which is a primary necessity. The advantages of afforestation can be summarized as an increase in timber and fuelwood production from areas which are now unproductive, and an increase in employment resulting in higher incomes and better hydrological conditions which benefit agricultural and industrial development.

£3Bi2¥!!}ÊBÏ_ !}_s£f°?L§::î:a'tï9!2

In Table 1 an example is given of the employment needed in an afforestation scheme for planting and maintenance during 10 years. In this scheme the followinj suppositions have been made:

the afforestation is carried out in an area with a dry season and sparse vegetation, but erosion is not so severe that technical control measures ha' to be taken; one-third of the area to be afforested has a gradient of less than 15 and two-thirds has a gradient over 15 . Areas with a gradient below 15 are afforestated in the taungyasystem; in steeper areas this is not possible so afforestation has to be done by contract labour; 400 ha per year are afforested for 10 years. In the first year 88 mandays will be needed; this number increases to 180 in the 10th year; the employment required for opening up the area has not been taken into consideration; in areas invaded by Imperata app. , the employment rate will be higher.

With an mean annual growth of 10 m /ha, a sustained yield of 40,000 m /year is possible. If the total area is managed on a sustained yield basis, sustained employment is obtained for 315 people on 4,000 ha (or about 1 person per 12 ha). The area needed to employ one person in forestry is about equal to the area need in shifting cultivation.

Table 1. Mandays needed for planting, maintenance, and exploitation of forest plantations during a 10-year period.

Year

0 1 2 3 4 5 6 7 8 9

10

Taungya < 15 md/ha

24 10 12 6

11 3 2 -5 -2

Production 10

Wage ear-ningo

md/ha 78.5 13 13 7

13 3 3 -5 -2

m /yr/hi

1/3 Taun

gya 2/3 Wage earning md/ha

60.3 12 12.7 5.7

12.3 3 2.7 -5 -2

Number md per 400 ha

24,120 4,800 5,080 2,680 4,920 1,200 1,080

-2,000

-800

Î; exploitation 40, (1 m : l u d )

Annual establishment Number mandays and maintenance

24,120 24,120 + 4,800 28,920 + 5,080 34,000 + 2,680 36,680 + 4,920 41,600 + 1,200 42,800 + 1,080 43,880 43,880 + 2,000 45,880 45,880 + 800

000 m 3 = 40,000

400 establishment

= 28,920 = 34,000 = 36,680 = 41,600 = 42,800 = 43,880

= 45,880

= 46,680

md

-

ha Number o: persons (275 md 1 year)

88 105 124 133 151 156 160 160 167

' 167 170

31 145

'»'»I« T o m Tr-nnirsl Silviculture. 1973)

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4 Silvicultural aspects of afforestation on eroded soils

4.1 Site preparation

Good site preparation is essential for afforestation on eroded soils. This means that besides opening up the area, careful attention should be paid to: a) clearing vegetation which may cause root and light competition, b) tilling th soil to improve the physical soil characteristics and c) providing soil conserva Site preparation may be done completely or in strips (depending on the soil, slo gradient, and existing vegetation of the area to be afforested). The main characteristic influencing site preparation in eroded areas is the soil erodibility. The erodibility of several soil groups present in Vietnam is given in table 2.

Table 2: Erodibility of Soil Units in Vietnam.

High erodibility Moderate erodibility Slight erodibility Variable erodibility Regosols Aerosols Ferralsols Fluvisols Lithosols Ultisols , (Nitosols) Vertisols

The slope of areas to be afforested may be divided into the following classes in relation to site preparation:

Slope > 50% (25 1 : Site preparation in small strips (1-2 ml with an intei of at least an equal width arranged along contour lim On soils with high erodibility only spot preparation : used.

Slope 15-50% (10-25 ) : Site preparation in strips of 3-5 m with intervals of 1.5-2 m, arranged along contour lines.

Slope 5-15% (3-10 ) : Site preparation in strips of 10-20 m with intervals < 2-3 m arranged along contour lines.

Slope < 5% (3 ) : Site preparation in strips along contour lines is onl; needed on soils with high erodibility.

Sometimes it will be necessary to construct terraces.

In areas with valueless shrubs or grasses, it will often be necessary to clear tl vegetation. When a decision has been made to clear the vegetation, the effects this will have on root and light competition and on increased erosion and insolal have to be taken into account. The decision will depend on the local climate, so: vegetation and species to be planted. The clearing can be done best in strips by burning, poisoning or cutting of shrubs and ploughing of grasses and weeds or a combination of these techniques.

Burning has advantages as well as disadvantages: it is a quick and easy way to control grasses and weeds, nutrients are directly released to trees, and it imprc the structure of heavy soils (but it should not be done on light soils). On the other hand, it decreases the amount of humus, affects the soil microfauna and flc deeply rooted grasses are not completely killed, and it is difficult to control. In addition, burning by the government or a company creates a conflict with shifl cultivators who have been restricted in their use of burning. Cutting the vegetation is often insufficient; the roots will shoot up again and consume soil moisture. It can be prevented by poisoning stumps. Soil cultivation may consist of hoeing, harrowing, plowing, deep-plowing, soils ripping or subsoiling; these methods depend on the intensity of site preparation and the soil layer to be affected. Physical properties of the soil are improved by tillage and weeds are controlled. However, in certain cases (sandy soils) cultivation may cause soil structure to deteriorate, increasing the risk of erosi Sometimes secondary weeds may develop which are difficult to control. Generally, the soil is tilled at the beginning or the end of the dry season. In areas with s slope up to 5% it can be done over the entire area, but on steeper slopes it has

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to be done in contour strips. Sometimes the system of tied ridging is applied. On very steep slopes > 30% and on shallow soils, soil cultivation is limited to spots of 1-2 m . Once the ground is ready for planting, planting holes should be dug (sometimes such pits are dug without previous soil tillage).. Building terraces is expensive both in construction and -maintenance. But sometimes it is necessary in order to conserve water and to prevent soil erosion, e.g. on steep slopes and highly erodible soils. Mostly the terraces are built at a gradient of 0.5% along contour lines. The distance between the terraces depends upon the slope (table 3). Terraces may be short (2-3 m Lor up to several hundreds meter in ength, they may also have a cresent shape.

Table 3: Distances between terraces as related to gradient.

Distance between terraces (ml

3 % ( 1.35°) 6 % ( 2.78 )

10 % ( 4.50 1 15 % ( 6.75 ) 25 % (11.25 ) 35 % (15.75 ) 50 % (22.50 ) 80 % (36.0 )

4.2 Cover crogs

2.0 2.5 3.0 3.4 4.0 4.5 5.0 6.0

Gradient Vertical Horizontal

67.0 42.0 30.0 23.0 16.0 13.0 10.0 7.5

Even if fast-growing species are used in afforestation of eroded plants, it still takes some years before the canopy is closed. Therefore with this establishment, soil conservation measures should be taken. Cover crops play an important role: these crops cover the soil in a short time, preferably without hindering the growth of the planted trees. Covercrops are gully discussed in main report VI.3.4.5.

4.3 Çhoice_of_tree_s2eçies

Reference is made to Appendix IV (Volume III), in which 112 tree species are dealt with; their requirement and possible uses are evaluated in a table. Species suited to soil conservation and soil improvement are discussed; they can be selecti by means of the table.

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Literature

Al' Benskii, A.V. & P.D. Nikitin (1956). Handbook of Afforestation and Soil Melioration. Isreal Program for Scientific Translations. Jerusalem.

Bennet, H.H. (1939). Soil Conservation. Mc Graw-Hill. Book Company, Inv. New York. Coster, Ch. (1938). Surficial Run-off and Erosion in Java. Tectona 31 (9/10):

719-728. Dames, T.W.G. (1955). The Soils of East Central Java. General Agricultural Research

Station, Bogor. Gonggrijp, L. (1941). Het Erosie-onderzoek (Erosion Research, in Dutch). Tectona

34/35: 200-220. Hudson, N. (1971). Soil Conservation. B.T. Batsford Ltd. London. Keilman, M.C. (1969). Some Environmental Components of Shifting Cultivation in

Upland Mindanao. The Journal of Trop. Geography 28: 40-56. McComb, A.L. & H. Zakaria (1972). Soil Erosion in Upper Solo River Basin, Central

Java. Rimba Indonesia 16 (1/2): 20-31. Study Team Tropical Silviculture (1973). Afforestation of Eroded Soils in Java

(Indonesia). Review of Literature, State Agricultural University, Wageningen. The Netherlands.

Weidelt, H.J. et al. (1975). Manual on Reforestation and Erosion Control for the Philippines. Schriftenreihe der Deutscher Gesellschaft für Technische Zusammenarbeit (G.T.Z.) Eschborn.

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