Vegetation of Southeast Asia Studies of Forest Types 1963-1965

completely absent. The undergrowth consists of bamboos, especially
Bambusti arundinacea and Dendrocalamus strictus; and a grass cover up
to 3 feet (1m.) tall, composed mainly of species of Andropogon.
The dominant and most characteristic tree in the Dry Mixed Deciduous
forest in northern Thailand, especially around Lampang, Ngao
and Prae, is Teak (Tectona grandis). Trees commonly associated with
Teak in this forest are: Acacia catechu, Anogeissus 1atifolia, Cassia
fistula, Terminalia tomentosa, Pterocarpus macrocarpus, and species
of Dalbergia and Diospyros.
The Dry Mixed Deciduous forest yields a series of timbers in
addition to certain minor forest products. Among useful timbers, in
addition to Teak, are: Adina cordifolia, Afzelia xylocarpa, Dalbergia
barjenais^ D. dongnaiensis and D. Oliverii, Erythrophloexim succirubrum
and E. teysmanj-i, Diospyros mollis, Nauclea orientalis Pberocarpus
macrocarpus, Tetrameles nudiflora, Vitex peduncularis, and Xylia kerrii.
Minor foreFt products furnished by this forest type include:
tannin from species of Terminalia, Anogeissus, Acacia and Diospyros. .
Cut'jh, also a tanning material, is obtained from Acacia catechu, and
myrobalan from Terminalia chebula. A red dye is> extracted from
sappan wood (Caesalpinia sappan); a yellow olye from Curar.ia ,iavanensis;
and a fast, shiny-black dye from the fruit of Diospyros rnollis.-
A large proportion of the population in Southeast Asia lives within
the range of Deciduous forests. Most of the food crops, including
vegetables and citrus fruits, as well as such fiber-yielding plants
as cotton and kenaf are grown in the type of land where this forest
flourishes.
(8) DECIDUOUS DIPTEROCARP FOREST
This forest type occupies vast tracts in northern, central and
northeastern Thailand, out is sparse in the Peninsula. It covers
about 57,000 square miles (lU2,OCO sq. kms.), equivalent to about
45 percent of the country's total forested area. In Vietnam, Laos
and Cambodia, likewise, it is the predominant and most extensive forest
type. In general appearance it is of open nature, with trees mostly
small to medium in size. It corresponds to what French ecologists
and foresters, who have studied the vegetation of Indochina, classify
as 'forets Claires'. The soils are generally sandy, gravelly, or
lateritic, and have a profound influence on the nature and composition
of this forest type.
The tree species are more or less mixed, although there is a
tendency towards gregariousness, with dominance by one or a few tree
species. Dipterocarp trees which predominate in thio forest include:
Dipterocarpus intricatus, D. obtusifolius and D. tuberculatus, Pentacme
siamensis and Shorea obtusa.
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