UNIVERSITI PUTRA MALAYSIA STUDIES ON GERMINATION AND...

UNIVERSITI PUTRA MALAYSIA

STUDIES ON GERMINATION AND SEEDLING GROWTH OF NEOBALANOCARPUS

HEIMII (KING) ASHTON

SITI RUBIAH ZAINUDIN

FH 1990 10

STUDIES ON GERMINATION

AND SEEDLING GROWTH OF NEOBALANOCARPUS

HEIMI I (KING) ASHTON

By

SITI RUBIAH ZAINUDIN

Thesis Submitted in Ful f ilment o f the

Requirements for the Degree of Master of Sc ience in the Faculty of Forestry

Univers it i Pertanian Malaysia

October 1990

ACKNOWLEDGEMENTS

I wish to expres s my most sincere and deepest thanks

to my supervisor, Dr . Lim Meng Tsai for his invaluable guidance ,

advice , encouragement , constructive criticisms and suggestions

throughout the pro j ect . To Associate Professor Mohd . Basri bin

Hamzah, my co-supervisor , I also wish to record my appreciation

for the guidance rendered .

Grateful acknowledgement is due to the Dean , Faculty o f

Forestry , Associate Professor Dr . Kamis Awang for providing the

f acilities . Sincere thanks are also due to the sta f f o f the

Faculty of Forestry , especially to Encik Haidzir bin Abdul

Wahab and Encik Yusri bin Abu for their invaluable assistance .

I a l so wish to express my special thanks to Cik Norizah

for her patience in typing this manuscript and to a l l who have

helped in one way or another in the completion of this pro j ect .

Fina l l y , I would like to dedicate this work to my family ,

husband and son Syed Hafiz , without whose love and devotion

this study would not have completed .

ii

TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS ii

LIST OF TABLES vi

LIST OF FIGURES viii

LIST OF PLATES x

LIST OF ABBREVIATIONS xi

ABSTRACT xii

ABSTRAK xiv

CHAPTER

ONE GENERAL INTRODUCTION 1

Status of Forestry in Malaysia 1

Obj ective o f Study 3

Literature Review 3

Chengaf Distribution and Regeneration 3

Seed Germination 4

Seedling Growth 9

Mycorrhiza and Soil 1 0

Light Requirement 13

Photosynthetic Characteristics of Tropical Forest Trees 1 5

iii

TWO SEED GERMINATI ON

Introduction

Material and Methods

Page

18

19

Results and Discussion • • • • • • • • • • • • . • • . • • . . • • • • 2 2

THREE: GROWTH

I ntroduction

Material and Methods • • • • • • . • • • • • • . • • • • • • • • . • . •

30

31

Results and Discussion • • • • • • • . . . • • • • • • • • • • • • • • 32

FOUR: PHOTOSYNTHESIS

Introduction 4 5

Material and Methods • • . • • • • • • • • • • . • • • • • • • • • • . • • 46

Resu lts and Discussion • • . • • • • • • • • • • • • • • • • • • • • • • 4 7

FIVE: MYCORRHI ZA AND SOIL

I ntroduct ion 53

5 5

S I X:

Material and Methods

Results and Discussion • • • • • . • • • • • • • . • • • • • • • • • • • 56

FIELD OBSERVATIONS

I ntroduction 62

study S ites • . • . • . . . • . . • • • • . . . . . • . . . . . • . • • • • • • • • 63

Material and Methods • • • • • • • . . • • • • • • • • • • • • • • • • • • 64

Results and Discussion • • • • • • • • • • • • • • • • • • • • • • • • • 65

iv

Page

SEVEN: GENERAL DISCUSSION , CONCLUSIONS AND RECOMMENDATIONS 73

REFERENCES 7 9

VITA 91

v

Table

1

2

3

4

5

6

7

8

LIST OF TABLES

Photosynthetic Rates of Tropical Species Measured at Light S aturating Intensities

at Temperatures between 2 20C and 300C • • • • • • •

E f fects of Light Treatment on Chengal seedlings ( Relative Growth Rates : Height ,

Page

16

Number of Leaves and Nodes ) . . ............ . . . 33

Correlation Coef fic ients of Seed Weight with Height , Number of Leaves , Number o f Nodes and Collar Diameter with Different Light Treatment • • • . • • • • • • • • • • • • . • •

E ffects of Light Treatment on Relative

Growth Rate for Collar Diameter , Leaf Area , Dry Weight of Lea f , Stem and Root of Chengal Seedlings • • . . • • • • • • • • • • • • • • • • . • •

Maximum Photosynthetic Rates of Chengal

Seedlings Grown under Different Light

33

35

Regimes • • • • • • • • • • • . • • • • • • • • • • • • . • • . . • . . • • • • 49

Maximum Photosynthet ic Rates of Some

Dipterocarp Species • • • . • • • • • . . • • • • • • • . . . • •

Mechanical Analysi s , Percentage Organic

Carbon and pH of Soil From the Ampang

Forest Reserve , Pasoh Forest Reserve and

5 1

UPM Nursery . • • • • . • . • • . • • • • • • . • • . . • • • • • • . . • 5 9

Distribut ion of Chengal Seedlings and

Saplings in Pasoh Forest Reserve ( no. per sq . m ) Around the Parent Tree . • . • • • • . • . • • • •

vi

68

9 Distribut ion of Chengal Seedl ings in Ampang Forest Reserve ( no . per sq . m ) Around the Parent Tree • • • . . • • • • • . • . . . . . . . .

vii

Page

70

Figure

1

2

3

4

5

6

7

8

9

1 0

11

LIST OF FIGURES

Distribution of Neobalanocarpus heimii

( Chenga1 ) in Peninsular Malaysia • • • • • • • • . • . .

Progres s of Seed Germination under Different L ight Condition

in Chengal

The Rel at ionship Between Seed Length And

Percentage Germination of chengal • . • . • . . • • . . .

The Relationship Between Seed Weight And

Percentage Germinat ion of Chengal . . . . . . • • . . • .

Longitudinal Section of Chengal

( Percentage Area Stained by Iodine ) Seeds

Col l ar Diameter Growth of Chengal Seedl ings under Different Light Intensit ies . . • . . . . . . . . .

Leaf Area of Chengal Seedl ings under

Different Light Intens ities . . . . . . . . . . . . . . . . . . .

Dry Weight of under Different

Leaf of Chengal Seed l ings Light Intensities • • . • • • • • • •

Stem Growth of

Different Light

Root Growth of Different Light

Weight of Seedl ings Intensit ies

Shoot grown

After

Chengal Seedl ings under Intensit ies . . . . . . . . . . . . . . . .

Chengal Seedlings under Intensit ies . . . . . . . . . . . . . . . .

and Root of Chengal under Different Light 12 months • • • . . . . . . . . . . . .

viii

Page

5

2 3

2 5

2 6

2 8

34

36

37

38

39

40

1 2

13

14

Photosynthetic Response curve of Chengal Seedl ings Grown under Dif ferent Light Intensities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Relationship between Density of Chengal

Seed l ings , Saplings and Distance from the Parent Tree in Pasoh Forest Reserve • . • • . . . .

Relationship between Density of Chengal

Seedl ings and Distance from the Parent Tree in Ampang Forest Reserve • • . . . • . • • • • • . . • • . . . .

ix

Page

48

6 6

69

P l ate

1

2

3

LIST OF PLATES

Chengal Seeds

Cross Section of Chengal Root Showing the Mant le and Hart ig Net ( Magnif icat ion 44x ) • • • . . • • • • • . • • . • . . . . • • •

Chengal Roots ( Ectornycorrhiza is

Brown in Colour ) ( Magnificat ion 44x ) • • • • • • • • • • • • • • • • • • • . . •

x

Page

2 4

5 8

5 8

LIST OF ABBREVIATIONS

a . s . l = Above Sea Level

FAA = Formalin Acetic Acid

FRIM = Forest Research Institute of Malaysia

IRGA = Infra-Red Gas Analyser

PAR = Photosynthetic Act ive Radiat ion

RGR = Relative Growth Rate

RLI = Relative Light Intensity

xi

Abstract o f thes is submitted to the Senate o f Universiti Pertanian Malays ia in ful f ilment of the requirements for the degree of Master of Science .

Supervisor

Faculty

STUDIES ON GERMINATION AND SEEDLING GROWTH

OF NEOBALANOCARPUS HEIMI I ( KING ) ASHTON

By

SITI RUBIAH ZAINUDIN

June 1990

Dr . Lim Meng Tsai

Forestry

Neobalanocarpus heimii ( King ) Ashton locally known as

chengal is endemic to Southern Thailand and Peninsular

Malay s ia . It is an important genera as it produces wood

that has become the standard by which many others are compared .

I t i s f a i r l y w i d e l y d i stributed but f o un d i n s c att ered

occurrence and at low numbers . This proj ect focuses on the

germinat ion , seedl ing growth , presence of mycorrhiza and

photosynthetic rates under dif ferent l ight condit ions. Soil

analys i s and f ield observat ion of seedl ing distribut ion around

the parent tree were also conducted . Germination o f chengal

was more rapid at lower l ight intensities than at higher l ight

intensities. The germinat ion percentage is also influenced by

seed size i . e . , the bigger the seed the better the germinat ion .

Treatment means for plant height and leaves showed no

xii

s igni f icant difference among treatments . However , the number

of nodes was s ignif icant in all treatments . Seed weight was

pos it ively correlated to height , number of leave s , number o f

nodes and col lar diameter at all l ight intensit ies . The

b iomass and total area of leaves per plant were highest at 5 5 %

RLI . Chengal grows on sandy loam soil with very low organic

carbon content and low pH . Ectomycorrhiza was found in roots

at the age of 2 months . The highest photosynthet ic rate o f

4 . 37 micro mol m-2 s-l was attained by plant grown at 5 5 % RLI

at the saturating photon flux of 400 micro mol m-2 s-l . P l ants

g rown at h igher and l ower l ight inten s it i e s had l ower

photosynthet ic rates of 1 . 30 micro mol m-2s-l and became

saturated at 100 micro mol m-2 s-l . After a seed fal l , the

number of seeds and seedlings around the parent tree is high .

However , there is correspondingly a high mortal ity rate with

high dens ity; the number fall ing to one quarter the total

number after a year . This study shows that the germinat ion

of chengal was best at 2 5% RLI and optimum growth of seedl ings

was attained at 5 5 % RLI.

xiii

Ab s t r a k t e s i s y ang d i kemukakan kepada Senat Un iver s i t i Pertanian Malays ia sebagai memenuhi keperluan untuk Ij azah Master Sains .

KAJIAN MENGENAI PERCAMBAHAN DAN PERTUMBUHAN ANAK BENIH NEOBALANOCARPUS HEIMII ( KING ) ASHTON

OLEH

SITI RUBIAH ZAINUDIN

June 1990

Penyelia Dr . Lim Meng Tsai

Fakulti Perhutanan

Neo b a l anocapu s h e i m i i ( K ing ) A s h t o n d i ke na l i s e b ag a i

c he ng a l a d a l ah endemik kepada Se l a t a n T h a i l and d an

Semenanj ung Malaysia . Ia merupakan salah satu kayu yang

men j adi satu piawai untuk perbandingan spes ies kayu keras l ain.

pro j ek i n i membe ntangkan k a j i a n ke a t a s per c amb a h a n ,

pertumbuhan anak benih , kehad i r a n m i ko r i z a d a n kadar

fotos intesis di bawah keadaan cahaya yang berbeza . Ana l i s is

tanah dan pemerhatian di lapangan terhadap taburan anak benih

di s eke l i l ing pokok i nduk j uga d i j a l ankan . P e r c amb ah a n

daripada chengal adalah lebih cepat pada intens it i cahaya yang

rendah iaitu 2 5 % RLI berbanding dengan intens it i cahaya yang

t ingg i . Peratus percambahan j uga dipengaruhi oleh saiz b i j i

benih iaitu bij i benih yang lebih besar memberikan percambahan

y an g l eb i h b a i k . P u r a t a r awat an untuk ket i n g g i a n

xiv

pokok dan daun menunj ukkan tiada perbezaan bererti d i antara

rawatan . Walau bagaimanapun, bilangan nod adal ah berert i di

antara semua rawatan cahaya . Berat bij i benih menunj ukkan

perhubungan posit i f dengan ket inggian , bilangan dau n , bilangan

nod dan garispusat kolar pad a semua rawatan cahaya . B iomas

dan j umlah keluasan daun per pokok adalah pal ing t inggi pada

5 5 % RLI . Chengal t umbuh d i t anah l iat berp a s ir dengan

kandungan organik karbon dan pH yang rendah . Ektomikoriza di

dapati didalam akar pada umur 2 bu lan . Kadar fotosintesis yang

pal ing t inggi , 4 . 37 micro mol m-2 s- l dicapai oleh tumbuhan

pada 5 5 % RLI pada keamatan ketepuan foton f luk 400 micro mol

m-2 s- l . Tumbuhan pad a intensit i cahaya yang lebih t inggi dan

rendah mempunyai kadar fotosintesis yang rendah iaitu 1 . 30

micro mol m-2 s-l dan menj adi tepu pada 100 micro mol m-2 s- l .

Selepas bij i benih gugur I terdapat banyak bij i dan benih

benih yang tumbuh mengelil ingi pokok induk . Bilangan

anak benih menurun dengan cepat dengan kenaikan j arak dari

pokok induk . Terdapat kadar kemat ian yang t inggi bilamana

ketumpatan ad a l ah s angat t i ngg i . O l e h i t u b i l angan

berkurangan kepada satu perempat selepas setahun . Kaj ian ini

menunj ukkan percambahan bij i benih chengal adalah pal ing baik

pad a 2 5% RLI dan anak benih chengal memerlukan keamatan cahaya

5 5 % RLI untuk pertumbuhan yang opt imum .

xv

CHAPTER ONE

GENERAL INTRODUCTION

status of Forestry in Malaysia

For the past three decades , tropical forests dominated by

dipterocarps have been exploited on an increasing scale due to

popular world demand for hardwood . Malaysia has 1 7 . 37 mil l ion

hectares of dipterocarp forests which contributed

s igni f icantly to industrial development , earning of foreign

exchange and soc io-economic changes ( Thang , 1986 ) . In view o f

the rapid depletion of the forest resources , ef forts to meet

future demand for t imber has forced the Forestry Department o f

Peninsular Malaysia to embark o n a Compensatory Plantation

Programme in which fast growing soft hardwood species such as

Acacia mangium and Gmel ina arborea have been successfully

planted .

I n a n att empt t o pursue a s u s t a i n a b l e y i e l d po l ic y ,

dipterocarp forests have to be regenerated after logging with

dipterocarps , either naturally or art i f ically by enrichment

planting . Natural regenerat ion of hill dipterocarp forest i s

general ly poor ( Wyatt-Smit h , 19 63; Burgess , 1976 ) . This i s due

to the variabil ity of terrain and stocking of economic spec ies .

Efforts to improve the regenerat ion status of these forests by

extending the natural distribution range of the more product ive

1

2

species through planting have not been very succes s ful ( Tang

and Wadley , 1 9 7 6 ) . T h i s c o u l d b e due t o t he l im it e d

understanding of the ecophysiology of the species.

Neobalanocarpus heimii ( King ) Ashton is l isted as one o f

the ten endangered species i n Malaysia ( Kiew et al . , 1985 ) . Due

t o it s s t re ngth and durab i l it y it i s o f g r e at e c o n o m i c

importance and demand for chengal local ly is high ( Maskayu , Vol

I, Jan , 1989 ) . It produces a strong and naturally durable wood

used for power-l ine posts , building boat s , carriage-bodies for

lorries and buses and frames for doors and windows .

Growth measurements of 319 planted chengal trees at Forest

Research Inst itute Malays ia at 22 years old has a mean girth o f

3 7 c m and a mean annual increment of 1 . 70 cm . Measurement o f

5370 trees i n Negeri Sembilan and Pahang gave annual increment

of 1 . 0 cm , so that in it s natural state , it probably takes

about 80 years to reach a girth of 153 cm, and 1 2 0 years to

reach a girth measurement of 230 cm ( Edwards , 1930 ) .

In the natural environment big trees of chengal are

usual ly found with a marked lack of suitable representat ion o f

sma l l and intermediate s izes ( Symington , 1943 ) . To ensure

s uc ce s s f u l regenerat ion o f cheng a l , t here is a need f o r

information o n its distribution and requirements for growt h .

These would help i n the management and manipulation o f the

3

forest to favour the regenerat ion of chengal in accordance to

its tolerance .

Objective of study

The unusual distribution of chengal suggest that the

ecological requirements for growth and regenerat ion may be very

specific . As a result of this , these studies were conducted to

explain how chengal estab l ishes itsel f . Parameters inc lude the

r e s po n s e of c heng a l s e ed l i ng s t o l ight , me a s urement o f

photosynthetic rates , presence o f mycorhizza and soil analys i s .

Literature Review

Chengal Distribution and Regeneration

Chengal is found throughout Peninsular Malaysia except

for Perlis and Malacca ( Symington , 1943 ) ( Figure 1 ) . It i s

found i n the lowland forests below 600m a . s . 1 and seems to

prefer sandy soil with l ittle laterite . It is also found in

low densities , Le less than 5 trees/ha ( symington , 1943 ) .

According to Symington ( 19 43 ) , numerous seedl ings and sapl ings

can somet imes be found beneath the parent tree . Chengal is a

l arge tree that can attain a diameter of up to 4 metres and

height of 42 metres to the f irst branch . Reported to be s low

growing , it does not achieve a maximum rate of growth unt i l it

is about 75 cm in girt h . However , measurements o f certain

4

plants have indicated that under favourable conditions growth

may be greater than mentioned above ( Symington , 1 9 4 3 ) .

According to the Forest Research Inst itute of Malaysia

Phenology Reports ( 1989 ) chengal flowers and fruit s every year .

Flowering does not seem to occur in mast with f l owering o f

other species of Dipterocarps ( Ng , Pers . comm . , 1 9 89 ) . I t

begins to bear flowers and fruits while sti l l young , and

planted trees have been known to bear fruits at less than ten

years old ( Symington , 1943 ) .

Chengal seeds are heavy and wingless and hence dispersal

i s restricted. Seeds are dispersed by animal s and by rol l ing

down h i l l s lopes. Because of its l imited dispersal mechanism

seedl ings are usually found in high densities beneath the

parent trees ( Symington , 1943 ) . According to Symington ( 19 43 ) ,

although these seedl ings are able to survive for long periods

under dense shade , light is still required for better growth .

Seed Germination

Seeds of many forest trees of the humid tropic s germinate

soon after dispersal . Germination of dipterocarps seeds is

rapid and Ng ( 19 78 ) concludes that rapid germination gives the

plants the advantage of escaping seed predation. For example ,

04°

2

1 QOO[

, '.

.- ..... " .

. . · /1···········

.. ·

;' .. _' . .

'O" . .� i ; .' � ..... ' . ."

•

�"'" . , . ,

• . .... ,�

Ke'; • = chenga i

o ,

"

' .. :

2,: , Sp krr.

• • . ' .

•

t

Figure 1 Distribution of Neobalanocarous he�mii (Chengali in P�ntnsular M�laysia

6

Dryobalanops aromat ica germinates within 1-2 weeks while Hopea

odorata , Shorea material i s , Shorea

lucida within 1-3 weeks .

maxima and Parashorea

The viab i l ity of seeds is af fected by various factor s .

Amongst them are the method of collection , stage of seed

maturation , infestation by pests, moisture content of seeds and

storage condit ions . Yap ( 1981 ) compared seeds o f Shorea

assamica col lected from the ground with those from the tree and

found l ittle dif ference in germinat ion percentage . Tang ( 19 71 )

has a l so indicated that selected good seeds of Shorea curt i s i i

from ground col lection are j ust as viable as those from

trees . However , ground col lected seeds of unknown

durat ion can show very low viabl ity ( Yap , 198 1 ) .

The viabil ity of seeds is also affected by the dif ferent

stages of maturation . Barnard ( 19 5 0 ) found that seeds with

green seed coats and brown wings germinate better than seeds

w i t h brown seed c o at s . A s l ight l y h i gher germi nat i o n

percentage was observed in the fruits o f Shorea materialis with

brown wings over those with part ially brown wings ( Yap , 1 9 8 1 ) .

In Shorea sumatrana , fruit s with green pericarps germinated

better than those with brown pericarps .

The e s t ab l i s hment o f c ert a i n d ipterocarp spe c ie s i s

critical where the product ion o f viable seeds i s very low . The

m a j or pe s t s o f seeds wh i l e s t i l l on t re e s are weevi l s

7

( Al c idodes spp . and Nanophytes spp . ) while Scolit id beetles

( Poec i i l ips spp . ) infest fal len seeds ( Dalj eet-s ingh , 19 74 ) .

Their infestat ion on Shore a curtisii reduces viable seeds to as

low as 1 . 6% of the total seeds produced ( Burgess , 1972 ) .

Mature dipterocarp seeds are rich in moisture and quickly

die when dehydrated ( Jansen, 1971; Tang , 1971; Tang and Tamar i ,

19 73; Sasaki , 1980; Yap , 1981 ) . These are typical recalc itrant

seeds which die quickly through dehydrat ion and can only be

stored wet ( Robert s , 1973 ) . Moisture is essent ial for

germination and seed can become non-viable in seven days if

allowed to dry . Corbineau and Come ( 1986 ) found that seeds o f

Shorea roxburghii and Hopea odorata are typical recalcitrant

seeds . The seeds cannot tolerate desiccat ion and die when

their mean moisture content drop by 20% ( dry weight basis ) .

Shorea roxburghii and Shorea ovalis seeds lose viab i l ity

at 20% moisture content ( Sasaki , 1980 ) while the seeds o f

Dryobanalops aromat ica are damaged at a moisture content below

35% ( Tamar i , 1976 ) .

Yap ( 19 8 1 ) proved that stored fruits of dipterocarps also

lose their viabi lity rapidly, and different species responded

to different storage condit ions . It was found that Dipterocarpus

baudii fruits with intact wings stored in closed bags at 1 40C

for 1 7 days was able to retain viability o f over 60% while

fruits with wings removed germinated poorly after storage in

8

the same condition . Dipterocarpus oblongifolius however , was

only able to retain viab i l ity of over 60% when stored in bags

with the air replaced with nitrogen for 60 days at room

temperature . Seeds of Shorea roxburghii and Hopea odorata

germinate very e a s i ly at high t emperatures w i t h opt i m a l

temperature close t o 300C o r 3SoC . According to Corbineau and

Come ( 1986 ) , germination was possible at 40oC , but this

temperature did not al low seedlings growth . Hopea odorata

seeds however , germinated perfectly down to lSoC , whereas

t h o s e o f Shorea roxburgh i i germ inat ed very poo r l y at

temperature below lSoC ( Corbineau and Come , 1986 ) .

Species found in c losed shaded habitats of moist temperate

and tropical environment are found to have l arger seeds than

those that regenerate in open , secondary habitat s ( Foster ,

1986 ) . It is general ly considered that large seeds enhance

seedl ings survival at low l ight intensities .

Large seeds may have nutrients , energy and water reserves

t o a c c o mmodat e metabo l i c requ irement s dur i n g per i o d s o f

dormancy . These reserves could allow seed survival unti l

c on d i t i o n s o f germ inat ion a n d growt h o f seed l i n g s are

favourable ( Foster, 1986 ) . Large seeds contain l arge amounts

o f secondary compounds that are used in the defence of the

seeds and seedl ings • Freeland and Janzen ( 1974 ) found that

s ome s e e d s cont a i n s e c ondary compounds l ike a m i n o a c id

analogues , alkaloids and phenolic compounds of up to 10% of

9

it s dry mass . Seeds of the shade-tolerant neotropical nutmeg ,

Virola surinamensis contain 1 5 . 4% dry mass of soluble tannin

( Howe and Vande Kerckhove , 1981 ) .

Large seeds also provide energy and nutrients necessary

for growth . Grime and Jeffrey ( 19 6 5 ) found a strong positive

correlat ion between seed s ize and max imum height of seedl ings

in nine temperate zone tree species which germinated under

shade . S imilar results were obtained by Howe and Richter

( 1 9 8 2 ) and Howe et al . , ( 19 8 5 ) for the s h ade- t o l e r ant

neotropical nutmeg , Virola surinamensis.

Seedling Growth

S hade i s an import ant prerequ i s it e for d ipte r o c arp

estab l ishment ( Whitmore, 1984 ) . Several species such as

Shorea leprosula , Parashorea tomentella and Dipterocarpus

s t e l l atus require s ome s h ade for seed l ings e s t ab l i s hment

( Nicho l son, 1960 ) .

General ly , most species produce a large populat ion o f

s ee d l in g s a fter a mas s f ru it ing a l t hough t he r e i s h i g h

mortal ity i n the f irst few months. Liew and Wong ( 19 73 ) in

their study on Parashorea tomentel la in Sabah , found that

seedl ing survival rates decl ined from 4 1 . 9 5 % in the first year

to 1 6 . 90% in the fourth year . The survival of dipterocarp

seedl ings , however , can differ cons iderably between species