progress of natural regeneration after final felling under the

Pertanikal (2), 126-135 (1978)

Progress of Natural Regeneration after Final Felling under theCurrent Silvicultural Practices in Matang Mangrove Reserve

P. B. L. SRIVASTAVA and DAUD KHAMIS1

Faculty of Forestry, Universiti Pertanian Malaysia

Key Words: Mangrove, Natural Regeneration

RINGKASAN

Kertas ini membincangkan keputusan penyelidikan he atas kemajuan pemulihan hutan-hutan bakauselepas tebangan, khususnya susunan jenis, pola taburan dan kepadatan stok.

Penyelidikan tersebut telah dibuat di Matang Hutansimpanan Bakau dalam Renj Port Weld. Kawa-san-kawasan yang dipilih adalah dari kelas-kelas 'inundation' III dan IV (Watson, 1928) dan mengandungitumbuhan jenis Rhizophora yang biasa. Pemulihan di dua kelas umur, iaitu 12 bulan dan 24 bulan selepastebangan, telah dibanci secara Bancian Linear (LRS).

Rhizophora spp. dan Bruquiere parviflora adalah jenis-jenis yang penting terdapat di dirian-dirianbaki. Bilangan anakbenih-anakbenih Rhizophora spp. di kawasan-kazvasan 12 dan 24 bulan selepas tebanganadalah 3701 dan 3376 seekar. Bilangan anakbenih-anakbenih B. parviflora pula di kawasan-kazvasan 24bulan selepas tebangan merosot secara berkesan, kepada 62 seekar jika dibandingkan dengan 1282 anakbenih-anakbenih seekar di kawasan 12 bulan selepas tebangan. Anakbenih-anakbenih Rhizophora spp. tidak matiberluasan di dalam jangkamasa tersebut. Kawasan-kawasan di kedua-dua kelas umur mempunyai bilangananakbenih-anakbenih yang mencukupi untuk mewujudkan dirian yang bercukupan stok pada hujung giliransekiranya kematian yang berluasan tidak berlaku.

SUMMARY

The paper presents the results of an investigation on the progress of regeneration of mangrove forestsafter logging with emphasis on species composition, distribution pattern and stocking.

The investigation was undertaken in the Port Weld Range of The Matang Mangrove Reserve. Theareas chosen belong to inundation classes III and IV (Watson, 1928) representing a typical Rhizophora type.Two age classes, i.e. 12 months and 24 months after felling, were sampled by means of Linear RegenerationSampling (LRS 1) method.

Rhizophora spp. and Bruguiere parviflora were the most important species in the residual stands with3701 and 3376 seedlings per acre of Rhizophora spp. respectively in the areas 12 and 24 month after finalfelling. There was a significant decrease in the number of B. parviflora seedlings in the areas 24 months afterfelling with only 62 seedlings per acre compared to 1282 seedlings per acre, 12 months after felling. There wasno large scale mortality in the Rhizophora seedlings with time during this period. At both the age classes, theareas had enough number of seedlings to produce a fully stocked stand at the end of rotation if no large scalemortality occurred.

INTRODUCTION though there was heavy damage to the existingIn a study conducted simultaneously, Sani s e e d l i n S c r 0P d u r i n g W ^ n g and transporting

(1977) discussed the effect of logging at the time operations, there was still a sufficient number ofof final felling on different aspects of natural seedlings in the residual stands to give an antici-regeneration in a typical Rhizophora type in pated yield provided no mortality due to exposureMatang Mangrove Reserve. It was found that or any other cause occurred.

Saham Pahang Berhad, Kuantan

126

P. B. L SRIVASTAVA AND DAUD KHAMIS

This study reports the progress of naturalregeneration during the two years after fellingin the same locality and type of forest. So far,there has been no quantitative information onthe progress of natural regeneration of Rhizophoraspp. In many areas, natural regeneration isdeficient due to yet unknown causes and theState Forest Department has to resort to plantingto obtain adequate stocking for sustained yield.Systematic studies are, therefore, needed todetermine the progress of natural regenerationof Rhizophora species after the final felling insome typical localities.

REVIEW OF WORK

Watson (1928), writing at a time when thecurrent techniques of treating a mangrove standwere only just beginning to be tried out, providesa comprehensive account of these forests whichis true to this day.

Noakes (1951, 1952) observed that (i) nosystematic investigation into the problem ofregeneration had ever been attempted, perhapsbecause the treatment of mangrove forest hadgradually come to be regarded as standardized;and as natural regeneration was expected tosucceed over two-third of the annual coupe,planting was not unduly expensive and therotation was long enough to "even off" the differ-ences, (ii) productive ability of Rhizophora spp.was high; fruiting began at four years of age andthough the number of seed varied considerablyfrom year to year, there was sufficient seed avail-able to re-stock all felling areas within two orthree years, (iii) Achrostichium aureum (Piai)which occurred throughout the whole range ofRhizophora forest responded readily to full lightand acted as a nurse to the existing seedlings;and if there were no seedlings then few could getin through tidal waves. Such areas could onlybe stocked by retaining seed bearers, (iv) theadverse influence of slash on the regenerationcould be minimised by constant vigilance toensure that all utilizable wood was removed fromthe felling area, and by lowering the rotation agethereby reducing the crown size of the final crop,(v) water could play an effective role in the dis-persal of seeds of Rhizophora spp. and in naturalregeneration only after the slash and most of thestilt roots of the felled trees had decayed, and(vi) large areas could not be regenerated withcoppice seedlings or artificially.

Dixon (1959) questioned the role of thewater-borne fruits in the normal process of naturalregeneration of Rhizophora forest and suggestedthat the continuous disturbance by subsequent

tides was the main cause for poor regeneration;he also pointed out that though the earlier workershad been aware that young seedlings of Rhizophoradamaged by logging could recover by coppiceshooting, there was no information available asto the number of seedlings capable of coppicingafter the final felling; he maintained that whilethe larger blanks were filled up by planting twoyears after exploitation, the smaller blanks werefilled up naturally after about seven years, providedthat weeds such as Derris uliginosa and Achrosti-chium aureum did not choke the site.

The situation has changed much during thelast two to three decades. Firstly, with the risein population and increased demand for themangrove wood, the area of exploitation hasinadvertently been extended which will requiremore .effort to ensure natural regeneration in theresidual stands. This applies to the Peninsulaas well to Sabah and Sarawak. Secondly, thehigh cost of planting and shortage of staff at alllevels to regenerate the deficient areas in thestipulated period are likely to restrict futureplanting. Thirdly, adequate quantities of seedmay not be available for planting. Fourthly,large areas of forest have been classifiedas unproductive in Matang Mangrove Reserveon the grounds that the crop consists of Bruguieraspp. Dixon (1959) pointed out that areas nowdue for felling carry a much greater proportionof this species in the crop. According to Mohd.Darus (1969) more than 500 acres of potentialRhizophora forest in Matang Reserve weredegraded on account of the presence of B. parvi-flora.

Paul Chai (1974, 1975) draws attention tomany problems faced in regenerating the exploitedmangrove forests of Sarawak: mounds, whereverthey exist, are almost immediately invaded byA. aureum which become particularly abundantin the exploited areas; the soil in the area isgreyish brown, thick and sticky clay and is non-porous and insufficiently aerated; regenerationof Rhizophora spp. and Bruguiera spp. on thistype of soil was found to be very scarce excepton the soft mud near river and stream banks.The seedlings do not get anchored easily, andeven if they do, most of them fail to develop.The Sarawak Forestry Department plans to studythe enrichment planting of logged-over areas asa means of regenerating the mangrove forestsand removal of slash in experimental loggingblocks to ascertain the possibility of improvingthe regeneration environment.

Abdul Manap and Srivastava (1975) havesuggested that studies be carried out to ascertainthe rate of decomposition of slash after loggingand its effect on natural regeneration.

127

NATURAL REGENERATION AFTER FINAL FELLING IN MATANG MANGROVE

Yusuf (1977) suggested that there is a needfor more intensive studies before logging isextended over large mangrove areas because theswampy habitat is also believed to be an importantnursery for many species of marine fish andprawns. Recent studies in Sabah have shownthat 82 per cent of the prawns exported fromSabah were of a species that spends a greaterpart of its lfe cycle in swamps and are caught inthe coastal waters close to sw-amps.

Silviculture

The silviculture of the mangrove forests isfairly simple compared to that of the inlandforests because the former are more homogenousand uniform. A clear felling system is used. Alluseless species left behind after harvest areslashed or poisoned. In many worked-overstands, blanks form about 25-30 per cent of thrharvested area. These areas are planted withRhizophora spp. usually two years after loggingwhen most of the slash has decomposed. In theAchrostichium aureum dominated areas plantingis recommended immediately after logging. Theseeds of R. mucronata are planted at 6' x 6'and those of R. apiculata are spaced at 4' X 4'.The planting operation is normally carried outduring the months of July - November to coin-cide with the fruiting season of Rhizophora spp.

There are three thinnings, all mechanical,in a 30-year rotation cycle: I. thinning at the ageof 15 years with 4' stick; II. thinning at the ageof 19-20 years with 6' stick and III. thinning atthe age of 25-26 years with 7' stick. The currentsilviculture prescriptions are described by Mohd.Darus(1969).

METHOD OF STUDY

(i) Description of the experimental area

This investigation was undertaken in theMatang Mangrove Reserve. All the study plotsare situated in the Port Weld range (Table 1).The areas chosen for the present study belongto inundation classes III and IV (Watson, 1928)representing a typical Rhizophora type whichforms the greater part of these swamps. Seventyto ninety per cent of the growing stock is domi-nated by Rhizophora species, R. apiculata andR. mucronata. The other inundation classeswere not covered in the present study becausethey could be too wet or too dry and would haveintroduced an additional factor which affectsnatural regeneration. These sites were selectedfor detailed sampling because they were typicalsites where no factor had apparently adverselyaffected the progress of natural regeneration.

However, a clear differentiation between the twoinundation classes is not apparent particularlyin regard to the quality of crop and the regenera-tion environment.

(ii) Field procedures

In the collection of data on the composition,distribution, and progress of regeneration andpercentage survival of the seedling crop of twoage classes, i.e. 12 months and 24 months afterlogging, Linear Regeneration Sampling procedure(LRS 1) (Anon, 1975) was adopted. This methodhas been standardized for the assessment ofnatural regeneration in the inland dipterocarpforests and was successfully used by Liew et al.(1977) in Sabah mangroves. A base line wasdrawn along a convenient boundary, such as achannel or compartment limits, and samplinglines were laid out on this base line at intervals of10 chains. Milliacre quadrats were laid outcontiguous to one another on the right side ofeach sampling line. The occurrence of seedlingsof different species was recorded in the milliacrequadrats by complete count in three heightclasses, viz., Ho (0-1'), H, (l'-5') and H5 (5-10').

RESULTS AND DISCUSSION

(1) Composition of seedling crop

As many as nine species were recorded inareas 12 months after felling, viz., Rhizophoraapiculata, R. mucronata, Bruguiera parviflora, B.gymnorrhiza, B. sexangula, B. cylindrica, Avi-cennia species, Exoecaria agallochia and Heritieralittoralis. In areas 24 months after felling, thelatter three species were not encountered. How-ever, at both stages, Rhizophora species were thedominant constituents and B. parviflora was themost important associate in terms of frequency,density and abundance. In areas 12 monthsafter felling, Rhizophora species seedlings consti-tuted over 70 per cent of the crop (except inplot 3) and together with B. parviflora, made upover 99.9 per cent of the seedlings. In areas24 months after felling, the proportion of B.parviflora was further reduced. The crop becamemore pure with over 96 per cent of the seedlingsbelonging to Rhizophora species, mainly R.apiculata (Table 2, Fig. 1 and 2). /?. mucronatawas present in the soft mud along the banks ofthe rivers and channels. The discussion thatfollows deals with different aspects of the twomost important species.

(2) Abundance of natural regeneration

A wide variation was noted in the densityof Rhizophora species in different plots, 12 monthsafter felling (Table 3). It was possible to deter-

128

P. B. L SRIVASTAVA AND DAUD KHAMIS

TABLE 1Sampled sites and date of sampling

Stage

1. 12 months after felling

Total Acreage

2. 24 months after felling

Total Acreage

Date ofSampling

8.11.76

8.11.76

9.11.76

9.11.76

8.10.76

11.11.76

3.11.76

Compt.No.

18(A)

18(B)

27(A)

27(B)

18

39

41

PlotNo.

1

2

3

4

5

6

7

CoupeNo.

1/75

53/74

27/74

13/75

28/74

35/73

3/74

Area(acre)

30.0

32.0

34.0

24.0

120.0

43.5

46.5

20.0

110.0

No. ofmilliacrequadrats

304

410

227

265

393

460

194

TABLE 2Percentage Stocking by Species

Stage

12 months after felling

24 months after felling

PlotNo.

1234

Av.

567

Av.

Rhizophoraspp.

77.0985.4942.8585.2372.67

97.0898.7296.1597.32

B.parviflora

22.8714.4457.1514.7727.30

2.651.041.861.85

Rhizbphora spp.& B. parviflora

99.9699.93

100.00100.0099.97

99.7399.7698.0199.17

B. parviflora& other spp.

22.9114.510.000.009.36

2.921.283.852.68

Otherspp.

0.050.070.000.000.03

0.270.241.980.83

TABLE 3Abundance of seedlings in different plots, 12 months after felling

Plot No.

1

2

3

4

Mean/acre

Standard Error

S.E.%

95% Confidence limit

LowerConfidence limitper acre

UpperConfidence limitper acre

Number of plants per acre

Rhizophora spp. B. parviflora

5417 1607

4088 691

1647 2197

3654 633

3701 1282

781 378

21 29

1219

6183

80

2484

129


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CL

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130

P. B. L. SRIVASTAVA AND DAUD KHAMIS

100 I

(/)g> 80

CO

I

60

20

plot 5

Rhizophora species

plot 6

Localities

plot 7 Average

Bruguiera parviflora

other species

Figure 2. Histogram showing percentage stocking by species forareas 24 months after felling.

mine the coefficient of variation for a completecount of the seedlings was carried out. Themaximum number of seedlings (5417/acre)was recorded in plot 1 and the minimum (1647/acre) in plot 3. The variation in the case of B.parviflora was greater (c.v. = 59 per cent) thanin Rhizophora species (c.v. = 42 per cent). Rhizo-phora seedlings outnumbered B. parviflora bynearly three times. There were, on an average,3701 seedlings of Rhizophora species per acrewith a standard error of 21 per cent and a rangeof 1219-6183 seedlings per acre compared to1282 seedlings per acre of B. parviflora with arange of 80-2482 per acre with a standard errorof 29 per cent (P<0.05).

At this stage the most abundant height classin both species was Hi (the seedlings betweenone to five feet), accounting for 91 per cent ofthe seedlings of Rhizophora species and 85 percent of B. parviflora. The other two classes werepoorly represented, Ho having the least numberof seedlings in Rhizophora species and H5 in B.parviflora. The number of seedlings of B.parviflora was four times that of Rhizophoraspecies in Ho class. But in H{ and H5 heightclasses, Rhizophora species seedlings were threeand seven times more abundant than B. parviflorarespectively. These two characteristics i.e. pre-dominance of Rhizophora species and B. parvifloraand Hj height class appear to be typical of this

131


age group. The two species made up 90 per magnitude of variation in the number of seedlingscent of the residual stand. of the two most dominant species i.e. Rhizophora

species (c.v. = 24 per cent) and B. parvifloraThe analyses of different aspects of density (c.v. = 36 per cent) was reduced. In the case

of seedlings in areas 24 months after felling are of R. apiculata, the number of seedlings variedshown in Tables 5 and 6. It is evident that the between 2526-4125 per acre in different plots

TABLE 4Number of seedlings per acre in different height classes, 12 months after felling

PlotNo.

1

2

3

4

Av.

o</ O

Rhizophora

Ho

130

6

6

8

38

1.0

Hi

5123

4025

1103

3196

3362

90.8

spp.

Hs

163

56

538

450

302

8.2

B.

Ho

243

166

115

58

146

11.4

parviflora

H i

1333

491

2003

554

1095

85.4

H 5

30

34

79

21

41

3.2

Ho

373

172

121

66

185

3.7

Total

Hi

6456

4516

3106

2750

4457

89.4

H5

193

90

617

471

343

6.9

GrandTotal

7022

4778

3844

4287

4984

-

TABLE 5Abundance of seedlings in different plots, 24 months after felling

Number of plants per acrePlot No.

Rhizophora spp. B. parviflora

5 2526 69

6 3477 37

7 4125 80

Mean/acre 3376 62

Standard Error 464 13

S.E. % 14 21Lower confidencelimit per acre 1379

95% Confidence limit Upper confidencelimit per acre 5374 118

TABLE 6Number of seedlings per acre in different height classes, 24 months after felling

r>i A.PlotNo.

5

6

7

Av.

o/o

Rhizophora

Ho

32

0

60

31

1

Hi

2494

1064

2090

1883

56

spp.

H 5

0

2413

1975

1463

43

Ho

28

0

0

9

15

B. parviflora

Hi

41

13

15

23

37

H5

0

24

65

30

48

Ho

60

0

60

40

1.2

Total

Hi

2535

1077

2105

1906

55.4

H5

0

2437

2040

1492

43.4

Total

2595

3514

4205

3438

-

132


with an average of 3376 seedlings per acre and arange 1397 - 5374 (P<0.05) and a standard errorof 14 per cent. In the case of B. parviflora, thenumber varied between 37 - 80 per acre indifferent plots with a mean of about 62 seedlingsper acre and a range of 6-118 (P<0.05) and astandard error of 21 per cent. At this stageRhizophora species seedlings were even moreabundant, being about 50 times as many as thoseof B. parviflora seedlings.

Hj was still the predominant height classthough the number of seedlings of B. parviflorawas slightly more in H5 than in H]. The propor-tion in H] seedlings, however, decreased substan-tially from 91 per cent to 57 per cent in Rhizophoraspecies and from 85 per cent to 37 per cent inB. parviflora within a year. Ho class was verypoorly represented. In all cases Rhizophoraseedlings were more abundant than B. parviflora,Ho (3 times), Hi (81 times), H5 (nearly 50 times).This indicates that there was almost no additionto the natural regeneration in the form of newrecruitment during the two years after felling;the present crop of seedlings, which shows pro-gressive height growth, is the one which survivedthe onslaught of the final felling.

(3) Mortality

In general, there was a decrease in the numberof seedlings with time after logging. As againstan average of 3701 seedlings per acre of Rhizo-phora species 12 months after felling, there were3376 seedlings per acre of these species 24 monthsafter felling. A much higher rate of mortalitywas observed in the seedling crop of B. parviflora.There were, on average, only 62 seedlings peracre 24 months after felling compared to 1282seedlings per acre 12 months after felling (Tables3,5).

While a low rate of mortality in the seedlingscrop of Rhizophora may be due to "naturalthinning" of the excess number of seedlings in afew over-crowded patches, the cause for the sharpdrop in the number of B. parviflora seedlings arenot easy to find. It may be due to both inter-and intraspecific competition. Almost all speciesfound in the swamp are light demanders andtherefore the high rate of mortality of B. parvifloraseedlings in these areas may be due to shadecreated by the more vigorously growing Rhizo-phora seedlings. The analysis also showed thatmost of the dead seedlings of B. parviflora weresmaller, belonging to height classes less thanfive feet. The death of the young seedlings couldalso be due to heat and dehydration broughtabout by the decomposition and collapse of stiltroots, stumps and other remains of the felled treeswith time,* thus depriving the young seedlings of

shade. The movement of partially decomposedslash during flooding can be another cause. Infact, Watson (1928) considered movement ofsemi-decomposed slash due to tidal action oneof the most important causes of mortality oftender seedlings which accounts for blanks inthe logged-over areas. The damage caused bythe attack of crabs or monkeys (Noakes, 1951)appears to be negligible in the naturally regene-rated stands at this stage. Liew et at (1977) alsonoted large scale mortality of B. parviflora seed-lings with time.

(4) Adequacy of natural regeneration

(i) 12 months after fellingIn the inland forests, an area is considered

adequately regenerated naturally if it has a mini-mum stocking of 300 well distributed seedlingsof important timber species per acre with anallowance for 10-12 per cent mortality (Anon,1975). However, no such criterion exists for anyspecies of mangrove swamps in the Peninsula.The figure acceptable for inland forests would notapply to the mangrove swamp species becausethe growth rates of the species and the silviculturesystem are different.

In the residual stands of the mangroveforests, even if each milliacre plot contains aminimum of one seedling, the stocking would beonly 1000 seedlings per acre which is far belowthe desired stocking needed for the developmentof a productive stand. It is assumed (Sani, 1977)that the number of stems present at the time offinal felling varies between 500 - 800 per acreand planting with Rhizophora apiculata is carriedout at 4' X 4' yielding 2722 seedlings per acre.The number of stems per acre after the first,second and third thinning will be 2722, 1210,889, respectively. These computations take intoaccount normal rate of mortality, if any, so as toyield a well stocked stand at the time of finalfelling. This means that there should be a mini-mum of three seedlings per milliacre plot in theregenerated stands before the first thinning iscarried out if a potentially productive stand forthe next rotation is to be developed.

On the basis of the above assumption, for anarea to be adequately stocked, there must be atleast 54.45 per cent of the total milliacre plotswith fvwt seedlings each, or 68.06 per cent con-taining at least four seedlings per plot, or 90.75per cent with at least three seedlings per plot inorder to have at least 2722 stems per acre at thetime of first thinning.

The average number of the seedlings (irres-pective of height) of the preferred species (Rhizo-

133


phora spp.) per acre is more than 2722 except inplot 3 which carried only 1647 seedlings per acre(Table 3). The analysis of the basic data furtherindicates that the seedlings are evenly dispersedin all the stands sampled in the present study.As many as 60 per cent of the plots had two ormore seedlings and the blanks constituted onlyabout 25 per cent of the plots. This is probablydue to the fact that the crop on the most productivesites in this area is homogenous, mainly of Rhizo-phora species.

Plot 3 (Tables 3 and 4) shows an interestingdistribution pattern of Rhizophora species andB. parviflora seedlings. The site seems to favourthe growth of the latter. By studying such sitesin detail it is possible to identify the factors respon-sible for the emergence of this 'weed' species on alarge scale in a typical and potential Rhizophorastand after final felling.

(ii) 24 months after felling

At this age also, as is evident from the tables5 and 6, plots 6 and 7 have more than an adequatenumber of seedlings of the preferred species onthe same criteria. Only plot 5 is slightly under-stocked. However, the percentage of blank plotsis increased slightly indicating that there hasbeen no new recruitment during this period eitherthrough water-borne seeds or from the seedbearers. It was surprising to note that there wasa significant decrease in the number of B. parvi-flora seedlings during this period. It comprisedonly 2.5 per cent of the total area. This appearscontradictory to the observations of workers whohad noted that this species tended to increase innumber with age in the regenerated stands. Itis probable that the incidence of B. parvifloraafter felling is greater in other inundation classes,such as V and VI, though it may dominate evenpotential Rhizophora stands, as in the case ofplot 3 (Tables 3 and 4). Similar observationswere made by Dixon (1959) and Mohd. Darus(1969). It is also possible that B. parviflora mightstart appearing three or four year after felling,ultimately forming an important associate ofRhizophora species. Further studies of more ageclasses, at least up to the stage of I thinning,and in the remaining inundation classes, needto be undertaken to determine the factors respon-sible for the predominance of B. parviflora in atypical Rhizophora type.

It was further noted that the number ofRhizophora seedlings of Hi class had gone up to1463 per acre (Table 6) as against only 302 seed-lings per acre (Tables 4) during the period ofone year. This indicates the rate of growth ofthis species under favourable conditions. Onthe other hand there was a sharp drop in Hj

height class of B. parviflora seedlings from 1095sedlings per acre (Table 4) at 12 months after

felling to only 23 seedlings per acre (Table 6)at the end of 24 months. The probable reasonsfor this decrease have already been stated.

CONCLUSIONS

On the basis of the present study in a Rhizo-phora species dominated forest on inundationclasses III and IV, the following conclusions canbe drawn:

1. Rhizophora spp. and B. parviflora are themost important species in the residual stands at12 and 24 months after felling. Seedlings ofother species are rarely present.

2. There is no large scale mortality in theRhizophora seedlings with time.

3. A large number of B. parviflora seedlingsdied between 12 and 24 months after final fellingprobably because of severe competition fromRhizophora seedlings, or exposure and dehydra-tion, or both.

4. Most of the stands sampled in the presentstudy were found to be adequately stocked, 12and 24 months after felling.

ACKNOWLEDGEMENTS

The authors are indebted to the Directorof the Perak State Forest Department and EncikXik Answar bin Nik Salleh (A.D.F.O. Taiping)for permission and help in various forms to carryout the survey. Thanks are also due to EnchikZainuddin, En. Khairi, and En. Majid, membersof the staff of Port Weld Range, for their assistance.

Special thanks are due to Professor HajiAbdul Manap Ahmad, the Dean Faculty ofForestry, Universiti Pertanian Malaysia, forapproval of the project, and for his encourage-ment, critical suggestions, and for providing thefield staff (Encik Harun, Encik Rahim, EncikHaidzir and Encik Ahmad). The authors arealso thankful to Dr. G.M. Bonnor and Mr. M.N.Asthana for their help in the data analysis.

Lastly, one of us (DK) wishes to thank hisfriend Abdullah Sani and his family for theirhospitality during the period of his stay at Taiping.

REFERENCES

ABDUL MANAP AHMAD and SRIVASTAVA, P.B.L. (1975):Effects of logging in mangrove vegetation inPeninsular Malaysia. ILP.M. (Unpublished).

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ABDULLAH SANI BIN SHAFFIE. (1977): Effect of loggingon the natural regeneration of Rhizophora speciesunder the current silvicultural practices in MatangMangrove Reserve. B.S. Thesis (Unpublished),Universiti Pertanian Malaysia.

ANON. (1975): A guide to Linear Regeneration SamplingOne (LRS - 1). Pamphlets, Forest Department,Malaysia.

DIXON, R.G. (1959): A working plan for the MatangMangrove Forest Reserve, Perak. Forest Depart-ment Publication.

LIEW, T.C, DIAH. MOHD. NOR, and WONG, Y.C.(1977): "Mangrove exploitation and Regenerationin Sabah." A New Era in Malaysian Forestry.Kuala Lumpur (Ed. Sastry, Srivastava and Manap),Universiti Pertanian Malaysia.

MOHD. DARUS HJ. MAHMUD. (1969): Rancangan Kerjabagi hutan simpanan paya laut Matang Perak.Forest Department Publication.

NOAKES, D.S.P. (1951): Notes on the Silviculture ofthe Mangrove Forests of Matang, Perak, MalayanFor. 14(4): 183-196.

(1952): A working plan for the Matang MangroveForests, Perak. Forest Department. Federationof Malaya Publication.

PAUL, P.K. CHAI. (1974): The potential of MangroveForests in Sarawak. Malayan For, 37(4): 284-288.

(1975): Mangrove Forest of Sarawak. MalayanFor. 38(2): 108-110.

WATSON, J.G. (1928): Mangrove Forests of the MalayPeninsula. Malayan For. Rec (6).

YUSUF NAIR. (1977): An appraisal of the economicpotential of Mangrove swamps, M.S. Thesis(Unpublished), Universiti Pertanian Malaysia.

(Received 28 August 1978)

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progress of natural regeneration after final felling under the

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