Vegetation of Southeast Asia Studies of Forest Types 1963-1965

The forests of South Vietnam contain several types of woody
vines or iianes, furnishing cordage. Other plants are sources of
latex for gutta-gum, such as species of Palaquiura obovaturj, an inferior
gutta-percha, and dyes. In addition, there are several species
of palms, some furnishing leaves to thatch huts, to make junk sails,
hats, and other similar uses.
Resins, which are natural or accidental exudations of pale
yellow or amber color, are furniched by species of the wood-oil
family (Dipterocarpaceae), especially of the genera Hopea and Shorea.
Exuded alone the trunk, branches and roots, such exudations have long
been gathered by woodcutters and others without any systematic
method of tapping, for making torches, to caulk boats and in the
manufacture of varnishes.
Wood-oil is Airnished by species of Diptarocarpus, especially
the tall 'dau' (D. alatus) or known as 'yang-khao 1 in Thailand. This
product is gathered in a primitive manner during the dry season, by
making a hollow with a hatchet in the trunk, about 3 feet above
ground (Fig. 17), "to gather the oil that flows out. When the flow
ceases the hollow is filled with straw or twigs, which are set on
fire to induce-the flow of oil. It is difficult to estimate the
50'eld of oil obtained from an individual tree. The natives claim
that a 30-year old tree will continue to flow for many years,, and
that the quantity obtained from a single tree may range up to about
oO pounds each year. In normal years it was estimated that the
southern portion of South Vietnam produced in excess of 2 million
pounds annually of wood-oil. This is used locally for making torches,
for caulking boats and junks, and for varnishing furniture.
Forests of Central Vietnam: Toe forest, of Annam, now divided to
form a section of South Vietnam and a portion of North Vr'etnara, at
one time covered approximately one half the total area of the former
French protectorate, or about 15 million acres (23,^0 square miles).
These forests form a continuation of those of North Vietnam, corresponding
to what vac formerly known as Tonkin, extending southward into
South Vietnam, and westward into Laos. They represent an enormous
timber wealth, containing such rare woods as rosewood, as well as
ordinary woods, some of them suitable for paper pulp.
Of broad-leaved trees, species of the wood-oil (Dipterocarpaceae)
and bean or pulse family (Leguminooae) are ^idespread and the most
valuable. tfhile the Dipterocarps furnish timbers for heavy construction,
those of the bean family supply fi>*e cabinet woods and
building timbers, and others for turning, carving and decorative puj>poses.
There are a number of species of Conifers, especially the 3-needled
pine (Pinus khasya) ar.d the 2-neerfled pirie(P. r.erkusii), scattered
over thousands of acres (Vies. 48-51). But some of the stands occur
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