A review of dipterocarps - Center for International Forestry Research

Introduction
S. Appanah
As a family of plants, Dipterocarpaceae may perhaps hold
the distinction of being the most well known trees in the
tropics. This famed family of trees stand tall in some of
the grandest forest formations the earth has ever
witnessed. Their overwhelming presence has led us to
call these vegetation zones dipterocarp forests. Currently
the dipterocarps predominate the international tropical
timber market, and therefore play an important role in
the economy of many of the Southeast Asian countries
(Poore 1989). The dipterocarps also constitute important
timbers for domestic needs in the seasonal evergreen
forests of Asia. In addition, these forests are sources of
a variety of minor products on which many forest
dwellers are directly dependent for their survival
(Panayotou and Ashton 1992). Despite such eminence
in the plant world, there has never been an attempt to
assemble under one cover all the principal aspects of
this exceptional family of trees. This is a serious lack
which we hope to start redressing and thus pay fitting
tribute to this great family of trees.
A greater concern however belies this slim effort.
The very existence of these trees and the forests they
stand in is at stake today because of the unrelenting pace
at which we are chopping down these forest giants and
converting their forests to other forms of landuse (FAO
1989). If present trends persist, not only will nations
and people become impoverished, but mankind will stand
to lose many species of plants and animals forever. These
dipterocarp forests, especially those everwet formations
of West Malesia, are among the richest worldwide in
terms of flora and fauna (Whitmore 1975).
Much of the knowledge on the species within the
Dipterocarpaceae exists in a disparate form even though
research on dipterocarps extends for about a century,
almost since the beginning of tropical forestry in British
India. Apart from some classical work on their taxonomy
(e.g. Symington 1943) and silviculture (Troup 1921,
Wyatt-Smith 1963), most other studies remain
fragmented. A uniform and comparative body of
information on dipterocarps did not develop. Studies
equivalent to those on acacias or eucalypts in Australia
never resulted (e.g. Jacobs 1981). This situation is the
result of a number of factors including:
1. The dipterocarps that comprise timber species are
distributed over a very wide range throughout tropical
Asia, covering several climatic zones and
geographies. The number of species in each country
varies from 1 to over 200 (Ashton 1982).
Consequently the depth of interest differs from
country to country.
2. The historical emphasis upon forest management
differs between countries, and this is reflected in
differences in institutional strengths and development
in research. While the dipterocarps are managed in
some countries, in other locales they are simply
exploited. A quick glance at the status of knowledge
on the dipterocarps in the region confirms this
unevenness. In some locations, the Indian continent
for example, the knowledge on many aspects of
dipterocarps is comprehensive. In others like Laos
and Cambodia, it varies from fragmentary to cursory.
3. Whatever scientific links that existed during the
colonial period have broken down. In fact, the first
forester brought in to attend to Malayan forest needs
was from British India (Wyatt-Smith 1963). Today,
scientific links between countries sharing the
dipterocarps have become desultory.
4. A considerable amount of information is sitting in
national institutes either in unprocessed form in
departmental files, or as internal reports, unpublished
theses, etc. Some reports are written in the local
language. Thus, a substantial wealth of knowledge is
simply not available to the vast majority of scientists.