A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
A review of dipterocarps - Center for International Forestry Research
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Management <strong>of</strong><br />
Natural Forests<br />
S. Appanah<br />
The view that it is not possible to manage natural <strong>for</strong>ests<br />
in the tropics <strong>for</strong> their timber has its adherents.<br />
Considering the widespread failures in many countries,<br />
such a view is conceivable. A <strong>review</strong> by <strong>International</strong><br />
Tropical Timber Organization estimated that only an<br />
insignificant amount <strong>of</strong> the world’s tropical moist <strong>for</strong>ests<br />
is sustainably managed (Poore 1989). Fortunately,<br />
numerous reports suggest otherwise <strong>for</strong> some<br />
dipterocarp <strong>for</strong>ests <strong>of</strong> Asia. The state <strong>of</strong> tropical <strong>for</strong>est<br />
management worldwide is in such a quandary that any<br />
success, however meagre, requires close examination.<br />
Such a success may provide the flicker <strong>of</strong> hope that is so<br />
urgently needed in our ef<strong>for</strong>ts to save these tropical<br />
<strong>for</strong>ests.<br />
The dipterocarp <strong>for</strong>ests in the perhumid zone <strong>of</strong> Asia<br />
<strong>for</strong>m the cradle <strong>for</strong> a considerable proportion <strong>of</strong> life<br />
<strong>for</strong>ms found on Earth. It is arguable that the only effective<br />
way to preserve a sizable portion <strong>of</strong> this biodiversity will<br />
be through effective management, including production<br />
<strong>of</strong> timber and other valuable products.<br />
Fortunately, history is on the side <strong>of</strong> dipterocarp<br />
<strong>for</strong>ests. The origins <strong>of</strong> scientific tropical <strong>for</strong>est<br />
management began in Asia, particularly in British India<br />
around the mid-19th Century. Together with teak, the<br />
dipterocarp <strong>for</strong>ests were among the first tropical <strong>for</strong>ests<br />
to be managed. The Indian experience <strong>for</strong>med the basis<br />
<strong>for</strong> management in the Malayan realm (Hill 1900). The<br />
conditions <strong>for</strong> management have changed considerably<br />
since then, but the experience and understanding gained<br />
<strong>for</strong>m an excellent basis <strong>for</strong> developing appropriate<br />
management regimes <strong>for</strong> tropical <strong>for</strong>ests.<br />
Forest Composition, Distribution and<br />
Structure<br />
Although the family Dipterocarpaceae is presently<br />
recognised pantropical, with three subfamilies<br />
Chapter 8<br />
Monotoideae (Africa, Colombia), Pakaraimoideae<br />
(Guyana) and Dipterocarpoideae (Asia), it is the last<br />
subfamily that is <strong>of</strong> significance as a timber group<br />
(Ashton 1982). The present <strong>review</strong> will be confined to<br />
the Asian subfamily. It comprises 13 genera and some<br />
470 species, distributed from the Seychelles in the west<br />
to Papua New Guinea to the east. In Chapter 1 more<br />
details on the taxonomy, distribution and diversity <strong>of</strong> this<br />
subfamily are given (see also Champion 1936, Symington<br />
1943, Ashton 1980, 1988).<br />
Dipterocarps are limited to tropical climates with a<br />
mean annual rainfall exceeding 1000 mm, with only short<br />
dry spells. The Asian dipterocarp <strong>for</strong>ests can be divided<br />
into two basic zones, viz. the Moist Tropical Forests and<br />
the Dry Tropical Forests (Champion and Seth, 1968,<br />
Collins et al. 1991). Within these two basic moist and<br />
dry tropical <strong>for</strong>ests, four <strong>for</strong>est types can be distinguished<br />
(Table 1).<br />
Our knowledge <strong>of</strong> these <strong>for</strong>ests, especially the<br />
distribution <strong>of</strong> <strong>dipterocarps</strong> within them is incomplete.<br />
This is particularly the case with <strong>for</strong>ests <strong>of</strong> Indochina<br />
and southern China. Under these circumstances, and <strong>for</strong><br />
the sake <strong>of</strong> brevity, the presentation is simplified to three<br />
groups <strong>of</strong> dipterocarp <strong>for</strong>ests, viz. the Dry evergreen<br />
dipterocarp <strong>for</strong>ests (Dry tropical <strong>for</strong>ests), Seasonal<br />
evergreen dipterocarp <strong>for</strong>ests (Tropical semi-evergreen<br />
and Tropical moist deciduous <strong>for</strong>ests), and the Aseasonal<br />
evergreen dipterocarp <strong>for</strong>ests (Tropical wet evergreen<br />
<strong>for</strong>ests). Some in<strong>for</strong>mation on their distribution and<br />
structure is given below.<br />
Dry Evergreen Dipterocarp Forests<br />
These <strong>for</strong>ests are found in Central and East India, Burma,<br />
Thailand and Indo-China. The <strong>for</strong>ests are dry, with less<br />
than 2000 mm <strong>of</strong> annual rainfall and a dry season <strong>of</strong> 3 to<br />
5 months. The <strong>for</strong>ests are medium in stature, with an even<br />
canopy and no emergents. Shorea robusta (Indian sal)