PHENOLOGY OF PHILIPPINE DIPTEROCARPS*

Chozab11ro TAl\lARl* and lreneo L. DOMINGO**

The Philippine dipkrocarp:o are the sourer of thr ,;e-callcd "Lauan" or ·'Philippine Mahogany· Jarnous in the world market. They will continue to supply adequately wood for the local and export market as long as the remaining virgin forest is properly regenerated and the logged-over forest more intensively tended. There must however be adequate supply of viable dipterocarp seeds or fruits.

Generally, there are many tree :~ecds with a short life in the tropics. Among them are the dip­terncarps, which have a notoriously short viability-only 2 to 3 weeks-under normal conditions. For thi,; reason. the collection must be perfectly timed, otherwise the fruits will die before they are collected. Proper timing is made possiblr through knowledge of the phenology of the various species of clipterocarps. E'ren in activities aimed at inducing flowering through chemical or mechanical means, a thorough knowledge of the species' phenological behavior is required.

As few studies on the phenology of Philippine dipterncarps are a\'ailable in the literature, the investigarion reported here hctci '.or objective to provide more information on the phenology of these important sources of valuable Limber.

Materials and methods Forty seven dipterocarp trees belonging to various species were selected from natural and

planted trees in the Makiling Forest, Los Banos, Laguna for phenological observations, All trees were rnature enough to have flowered and fruited at least once in the past (Table 1).

Observations were carried out once every 10 days, in recording the occurrence of the following events:

1 Flowering (1) Flower buds begin to swell (2) Flower buds begin to burst (3) Vigorous flowering stage (4) Most flower buds have opened

2 Fruiting (1) Begins to form fruits, petals start to fall (2) Fruit developing, green color (3) Fruit-wings start to change color from green to yellowish green (4) Fruit-wings start to turn brown (5) Fruits start to turn brown (6) Most fruit-wings brown (7) Most fruits brown (8) Fruits start to fall (9) Most fruits are falling

* The study was part of a cooperative research project between University of the Philippines at Los Banos and Tropical Agriculture Research Center (T ARC), Japan.

•• Visiting Scientist of Silviculture, University of the Philippines at Los Banos, College, Laguna, Philippines.

* * * Professor of Silviculture, the said University present a cl dress: Forest Research Department, PI COP, Bislig, Surigao de! Sur, Philippines).

(10) FruI.t fall cornpleted

BL)tanica.l spccirnt~ns fn)!Ti tbrt'C' herbari;·L Ea1-r1cly rht· h1._:,rbari•Y:1

t·nivt~rsity of the Phi1ippines at Los f3;~1iln~. the Phdippine ~:1clon:.1: herbariun1 ni the Forest Product:~ Rcsc:..ii'Ch ar:d , t,..Ju:i: .·.:::.''. · l)t.:. PRIDECO:\'[) were also exnminecL

Table 1 Number or trees awl species of <lipterocarp, seiec '-'·• :·,,,- 1J'·,,·1;;;ic,,:;, .. :, observtltions at the ~fakiiing Fort~~t. Los Barios, L:ig:.;ru., .:1hi~irpir~2:

Corninon narne

Dagang

Palosapis

Tailed-leaf panaw

Panaw

Apitong

Hagakhak

Foxworthy dalingdingan

Yakal-saplu.ngan

Bagtikan

Yakal

Guijo

Malaanonang,

Almon

Tiaong

Mayapis

Tangile

White lauan

Narig

'.Scientific N:une

Anfsr)ptera aurea Fnxv;"

-1 1!wrf!~·ta (HLCOJ Blume

Diptcrocarrus ccudatus Foxw,

f). gracilis Blun1C"

D. granrliJlorus Blc(i.

i). tvarburgii Brant.i.

llopea J~)x1vorthyi Elr-n.

If p!a;;ara (Bko.) \ 1id.

Pcrashorea niala:1nunan (lHcvJ

Shorea astyiusa Fcx,1.

S. guiso (Bk~c•o) B1urne

S. pulita Vid.

S. almon foxw.

S" agsaboensis Stern

S. f}a!osapis ~Blco,) :Mt'.rr.

S. po(vspcr:na (Hlci).) M-._:rr.

S. cantor-to VicL

Varin; whitji'Jrdh 1 'ox'V.-.

Total

Results and discussions

3

·, ·'

l

47

There were 48 cases of flowering and 2:-l cases of fruiting obse0:ed pericdicaH:,· trom ~:;eptember 1976 to July 1978 among the herbarium specimens collected during difforent year,, in tht· 1vfaki1ing Forest (Figure 1).

The climate of the Philippines has been classified into 4 types. The M,1kiling Fores(, L(\s Banu,,, and its surroundings in Laguna province lwlong to Type I, characterized hy two pronourn:.,•d seasons, dry from November to April and wet during the rest of the year. From the d;ita shown in Figure 1, it appears that the dipterocarps in the Makiling Fon:st flovver in hoth the dry and the wet season. every month except September. The largest number of flowering cases, 1.1,. ocu1rred in May, followed. in decreasing order, by 8 cases in February, 7 in March, Geach in April an<l JurH\ :i in October, 1 in January, 3 in i\.ugust, and one each in July, November. and December. In :,;onw trees, flowering spans over 2 months. It also appears that there are two peaks 1)f flowering, one in the favorable flowering season extending from January to June with a peak in :\:lay and rhe otht:- in the scanty flowering season from July to December with a peak in Octobc·r. ;lltbough th!re seems u, bra gap in September.

The highest frequency (9 cases) of fruiting occurred in August, follownl by· 4 cases in !\ti:;, July, and September, 3 in June, one in November, all fruitings occurring clurin_g Uw we! ,.,eason from

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.,···~

:-~- '~ 't:;: -· Fig. l FlowNi•,1,? ,rnd fruiting seasons of dipterocari,:, ; : :'1.fakiling

D

n 2

HnJ.id-wing,~d ~pn,JM

}fair)·k3.t ;1piton_g

H 1 :Ln~r;1ch1ptti

d;i]in~d\r:,:,,n

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H Yaluk;:,pl1,n_,;:;n

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S 5

S 6

Man~~a~mnrv

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.J.:rnon

S. r':on/ort,1 \':d

13J

134

May to October. Since there was no fruiting from December to Apnl, it appears that the f1D 1xers ii: the scanty flo,vering season did not to develop to fruib.

Data on flowering and fruiting classified by clinntic region are shown in Figures 2 and 3. There­the FORPRIDECOl\I climatic type classification was used, i.e., dry dmiate: dry from November to April and wet during the rest ot the year; wet climate: rainy throughout the yt ar v;iih very pronounced maximum rainfall from '.'Jovcmber to January, and one or two dry monthf:, :ind in­termediate climate: rainfall more or less e'>·enly distributed throughout the year wil h 3 to -1 dry months. Figure 2 shows that flowering peak took place in April in the dry region, in I\lay in the intermediate region, and in May and June in the wet region. Frmting peak occurred in May and

f

/·brrti' Qt.nu.<; ~-J<!. rec, Jan, Feb. Y...rr. !.pi:, :,t,_y _-;ui,1;' Ju1y .lng. ~P- '.:'ct.

_,,_::_.,;· ~ .l.:.i··G~

A1-4P -- Hl".-711 511-55

S'.>-6]-

~ ~ iii!!~~:~:.: s;g~ ......_,,_Ei3

'11-61.-:,ll--r -~SS-G3

Fig. 2 Flowering season of dipterocarps in different climatic regions in the Philippines

H:Jnth ~n1.ti'I Nov. Cec. Jro. Feb. i\'ar. ,\rx. Hoty .:'une July 1'.U'.:f, sep. O.~t.

:ll-55 -

--­D5-i7 ~ DS-04 A2-4S AZ-16 A2-f,7

N===•m-,e

D9-57 D7-57 --

-----Sll-U -Vl-35

-A2-(·0 H2-5S

'1giz 06-56 - 1)5- 77 -

S:i.1-5~ $6-Cii --

----S4-.l4 S5-6(' S"7-4P, -512-lt.

loiiiiiil,,

~~~:;:.:~ cJ7-63 :!3-. D4-55

- (S~--P-63

Fig. 3 Fruiting season of dipterocarps in different climatic regions in the Philippines

June in the dry and interrnedjate regions and 1n Septernber in the \Yet T'hcrc ',\':,±S .'2~ ro 1nonth difference in fruiting peak betYveen the dry and \Vf't regions (Fig:~1re 3) .. A_t the san1c tin1e. it appears that the flnvverlng and fruitin,~?: seasons in the ,vet and intern1ecli,tte longer period" than those in the dry regirrn.

Figure 4 vvas dr<1\vn after Foxworthy 's descriptions (1911} 1918 1 103B) regarding· th-:· fl(n~~enng and fruiting months of clipteroc;irps observed all over the Philippine~. Figt,re ::, is a diagram established by Delizo (1964). indicating the months when fruiting of diptnocarps is ubserved with variations depending on the species and the regions in the Philippines. ir is very difficult however. to determine the peak flowering and fruiting seasons of dipterocarps by such ways. As mentioned by Foxworthy and according to our continuous observations, the peak flm,vering and fruiting seasons vary for different species and for different individe:ils :n tb same species. The author concluded that tl1t:, variable clir;1atic conditions in the cliffertnt parts c,i d:e islands were probablv responsible for the widely extended seasons of flowering and fruiting among diptcmcarp~;

The data in this study were mostly based on the botanical speci:nei>S ,·ollected in the herbaria. Since these specimens sometimes included immature or damaged fruits, c,alv some of them indicate the proper fruiting season. As shown in Table 2, rhe flowering-to-fn,·,..ing periods (from the ap­pearance of flowers to maturity) of dipterocarps are. mostly, 2-6 months, and, in some cases, it takes more than one month from the fruit form to maturity (Figure 6), ,~nd many fruits fail d(nvn due to damage from insects, animals, heavy rain. and strnng wind in the latest phases of fn_1 it maturation. Based on the data from herl:larium specimens, Lmrnbao 11972) mentioned that, m mon cases, dipterocarps start to flower at/or before the beginning of the dry season during the seed ye;,r with variable flowering season, but he rlid not describe the differences in flowering and fruiting of dipterocarps depending on the climatic regions. Figures 2 and 3. indicate that in the dry climatic reg10n. dipterocarps flower from around the middle of the dry season, ,,-ith a peak at the end of the dry season, until the beginning of the wet season. A season lag in the peak flowering and fruiting of dipterocarps is usually observed between the dry. intermediate, and vvet climatic regions.

:. f'lo-ieru,g ~ar.'P

,\fJne, -::cc, ,Tan, ;"",:,\,.'.>'.;' • A;:JL l'by ,]l"'.,';. c-ul, :.u:i, Se,::,.(.Ct. -

.................. ..... - .....

Fig. 4 Flowering and fruiting seasons of dipterocarps in the Philippines by F, W. Foxworthy

d.ifferent Philippines

40

30

20

6 Modifications of share individual weight and germinability of Hopea foxworthyi fruits their maturing

process

ff nervosa

lepro.s,ula

i::~ . . martiniana

pan1ifolia

S. pauciflora

S. platyclados

S. resina nigra

S. resinosa

rigida}

2&112

4

3

3&1/44 2&1/2 2&1/2

5-6

2&1/2

2&3/4

4

3&1/2

4

4&

2&1/2

4

2&1/2-3

3

6

5

J}

6

& Tamari

& Loh

Tamarl

Ng & Loh

&

Burkill

Medway

Burgess

Burkill

Tamari

Ng & Loh

Ng & Loh

Burkill

Tamarl

Tama.ri

Tang

Tamari

& Loh

Ng& Loh

Ng & Loh

Burkill

Burk.ill

comm.}

1974

1974

1976

1976

1974

1974 1974

1976

1974

1974

1976

1972

l9l7b

1917b

1974 1976

1974

1917b

1976

1974

1917b 1976

1976

1972

1974 1974 1974

\922

138

the_: report Lhe senior author1 ba.sed on continuous ol1servations of pbenology in l(epong, VVe~.t \'lalaysia for three and haJf years (197()), the clipterocarps

w1:·rc forn,d le• be distributed nu'.. horizontally bm abu vertically and even within llw sarne clin1atic zone there \-Vere sC'asonal \rariatlons in rainfall. It 1,,,,.-as th:.::n stressed that accordingly 1

\·ecy careful anaiy,;i:: ,,]s needed to determim thf• l,JCai flowering and fruiting peaks of dip· terocarps. Foxwortbv '. i93?! also mentioned U1a!. the extended seasons of flowering and fruiting of dipkrCK8tps in the Philippines amnng different :,pecies and among individuals in the same species were caus,:d by the variable climmic conditions in different parts of the islands, within 8 given locality, and certiin tr,,es seemed to flower and fruit at nearly the same time year after year. Actually, the Makiling Foresr, Los Banos. L.1gm1a is located in the dry region according to the macro-climatic type clm,sificatic,n devised by i he Weather Bureau or by FORPRIDECOM. bnt the fiowct-ing and fruiting seasons of dipuTo,;,1ps are rather simil,tr to tho;,e of lhc \Vet region. In ?vlakilin.11.. dipterocarp flowering c1ss1.nnes different seasonal patterns. changing from dr,,; lo ,vet and sornetinws also wet lo dr\', whik nca k fruiting takes place iu Auge!>!.

Summary Data based on the rnmm1wus obsen-ation of dipterocarp phenology in Makiling using

specimens collected at '.ile iwrbarium of the Col!:-;;e of Forestry, enivt>rsity of the Philippiues at Lo2 Baims indicate that the fbwering season of diprerncarp,; takes place from February to May with widely extended season. Frnm August to Decer;;be,· flowering of dipterncarps is scanty with rare fruiting. Maturation of dipterncarp fruits takes place from Mc1y to Octolwr. coinciding with the wet season. in Makiling. Although the Makiling Forest in Los Banos, Laguna province is located in the clr"y' regwn of the Philippines, the flowerinr ;md iruiting habits of dipterocarps are rather similar to those in the wel region.

Accordmg to the general analysis of diptt:rncarp phenologr in the Philippines based on our data and on those of Lomibao the peak flowering season of dipterocarps occurs in April in the dry climatic reg10n. in \1av >1 '.he irnLrn1ediate climatic region, and in May and June in the wet dimatic region with wide],- ex'• .. 'h'(·,1 ,,,,asons. There is a two· to three-month difference in the peak fruiting ,·: ::,, ,,, r,f dipteroca~ps betwE·en the dry and wet climatic regions. 'The flowering and fruiting c,~-;i:0 un~ ,_1i the dipten,c:trps in the wet and inter:rnxliate climatic regions extend over a longer period ~nan lhnse of the dir,terncarps growing in the cir\', lim:•tic region.

Acknowledi;(ement The authors would like to E'Xpress their cordial appreciation to Dr. Abelardo G. Samonte,

Chancellor, Dr. Domingo M. Lantic,m. Vice-Chancellor, Dr. Romulo A. del Castillo, Dean of College of Forestry, University of the Philippines at Los Banos, Mr. Shiro Okabe, Director, Dr. Kan-khi Murakami, former Director, I):-. Sukeo Kawanabe, Head of Research Division 2, Tropical Agriculture Research Center, ".\fr. Mitsuma Matsui, Director, Dr. Takeshi Uemura, fonner Director, Dr. Ryookid.: foda, Head, Mr. Mit,,uo lwagawa, former Head of Silviculture Division. Forestry and Forest Pniducts Research Institute, Japan. for giving them the opportunity to carry out this study, Thcy would like to thank the various members of the College of Forestry, University of the Philippines, Los Banos for their kind assistance.

They gratefully aeknowledge the financial support extended by the Paper Industries Cor­poration of the Philippines that enabled the junior author to attend the symposium.

References 1) DELIZ() C, (1964): Forest Nursery and Plantation Handbook for the Philippines. U. P. College

of Forestry. 2) FERNANDO, F.S. (1977, Compiled): Notes on Philippine Dipterocarpaceae. Lecture Note in

Dendrology, Dept. of Forest Biological Science, U.P. Los Banos.

139

3) FOXWORTHY W. (1911): Philippine Dipterocarpaceae. Philippine Journal Science, C. Botany (6), 4, 231-285.

4) ---- (1918): Philippine Dipterocarpaceae IL Philippine Journal of Science (13) 3, 163-197.

5) ---- (1938): Philippine Dipterocarpaceae m. Philippine Jounzal of Science (67) 3, 241-331.

6) LOMIBAO A. (1972): Phenology of Some Philippine Dipterocarpaceae. Forpridecoin Digest (1) 1, 65-71.

7) NG F.S.P. and LoH S. (1974): Flowering-to-Fruiting Periods of Malaysian Trees. Malaysian Forester(37) 2, 127-132.

8) TAMAR! C. (1976): Phenology and Seed Storage Trials of Dipterocarps. Research Pamphlet No. 69, Forest Research Institute, Kepong, Peninsular Malaysia.

9) ---- and DOMINGO, I.L. (1978): The Properties of Some Philippine Dipterocarp Fruits. (Unpublished).

(Additional source of literature cited in Table 2)

10) BURGESS P.F. (1975): Silviculture in the Hill Forest of the Malay Peninsula. Research Pam­phlet No. 64, Forest Research Institute, Kepong, Peninsula Malaysia.

11) BURKILL I.H. (1917a): Notes on Dipterocarps 1, the Seedling of Anisoptera costata Korth.]. Straits Branch Roy. Asiat. Soc. 75, 43-48.

12) ---- (1917b): Notes on Dipterocarps 2, the Seedling and Seed Production in Some Species of Shorea.]. Straits Branch Roy. Asiat. Soc., 76

13) ---- (1922): Notes on Dipterocarps, the Seedling and Seed Production in Some Species of Shorea.]. Straits Branch Roy. Asiat. Soc.,

14) MEDWAY, L. (1972): Phenology of a Tropical Rain Forest in Malaya. Biol.]. Linn. Soc. 4, 117-146

Discussion Choob K. (Thailand): You have shown that some Dipterocarp species bear fruit up to twice a

year. In such a case do you find any difference in seed quality? What season (of seed crop) do you recommend for collection?

Answer: There is a difference depending on the species. Seeds should be collected when the wings turn brown. The best seeds are usually those collected in seed-years.

Katsuta, M. (Japan): It has been observed that irregularities in flowering time among in­dividuals within a species throughout the year affect seed production as well as seed quantity and quality. In the case of conifers and broad-leaved trees such differences induce low germinability and seed abortion while mating chances among individuals are reduced. What is the situation in the Dipterocarps and in general in the tropics?

Answer: This is a very complex problem. There are many genera and many species in the Dipterocarp family and there is a marked genetic diversity within a genus and between species within a genus. Also the ambient conditions have to be taken into account. In any case, provenance is very important.

Osumi, Y. (Japan): 1) What kind of environmental condition is stimulating flowering of Dipterocarps? 2) Is there any difference in maturing time between tropical monsoon and tropical rain forest species of Dipterocarps?

Answer: 1) Dry spell is favourable for flower bud differentiation and humidity for flower bud expansion or enlargement. 2) In the Philippines, the Dipterocarps start to flower in the middle of the dry season, with a peak at the end of the dry season. Flowering stops in the beginning of the rainy season. The flowering season covers a longer period of time in the Philippines than in Malaysia. In both countries two flowering peaks can be observed. However in the Philippines, unlike in Malaysia, flowers develop into fruit only in one season, namely from February to July.