Vegetation of Southeast Asia Studies of Forest Types 1963-1965

there is urgent need in Southeast Asia, ar> in other tropical countries,
for measures to control. land use, forest fires, forest cutting and
land development.
Climate; As in the adjoining countries of Southeast Asia, the
climate of Vietnam is a tropical monsoon or seasonal type, with high
temperatures and generally ample rainfall* The consideraole latitudinal
and altitudinal range of the country produces noticeable
climatic variations from one region to another, and the rainfall is
subject to annual fluctuations. As in Thailand, in South Vietnam the
rainy season ends in October, followed by a relatively dry, cod
season from November to March. Along the narrow coastal plains of
Annan, in central Vietnam, the rainy season may extend into January,
influenced by the prevailing typhoons. In North Vietnam the total
annual rainfall averages about 70 inches (1.750 rim.), compared with
80 inches (2,000 mm.) in South Vietnam, In North Vietnam, however,
the rainfall is more evenly distributed throughout the year. In addition
to the rainy season, there is a moderate amount of precipitation during
the winter or dry months, which is sufficient to produce a second grain
crop. In South Vietnam, however, it is virtually impossible to obtain
a second crop, without irrigation, during the dryj cool season on
account of sparse precipitation.
In North Vietnam the temperature range during the entire year is
greater than in the siouth. However, ever, in the. northern part of
the country, the nean monthly temperature seldom drops below 63° F.
Population: Official statistics for entire Vietnam are not available.
Estimates place the total population at between 25 and. 26
millions, with about I'l- millions in South Vietnam. In recent years
of conflict the population in the South has been increased by the influx
of more than one million refugees. These migrants, formerly
merchants, artisans, industrial workers and miners, have created an
economic problem in an area where the majority of the inhabitants are
small -scale farmers. The ye displaced persons from the North, as well
as those from the Interior of South Vietnam, rely more and more on
agriculture and the exploitation of forest products to meet their
necessities. Agriculture, particularly rice growing and rubber tapping,
provides a ] i veil hood 1'or about 90 percent of tae people. The remaining
10 percent depend on fishing, forestry and. mining for subsistence,
The population is unevenly distributed. For economic, social,
health and now political or military reasons, most of the people prefer
to live in the plains and. avoid the mountain areas. The result Is the
concentration of population^ especially in the delta regions.
The land use and population pattern of North and South Vietnam
are determined by variations in terrain, climate and soils. In South
Vietnam, with its great Mekong delta, it is estimated that, about 80
percent of the land is under cultivation; in the mountainous central