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