Vegetation of Southeast Asia Studies of Forest Types 1963-1965

The central region - Annara - is a narrow strip of territory,
about 60 miles (96 tons.) wide and 600 miles (960 kms.) long. The
main Annam Mountain chain, with peaks elevating up to 8,000 ft.
(2,500 m.), falls abruptly eastward to the narrow coastal plain.
Its rugged, eroded, seaward slop.;:-; are largely not suitable for conventional
crops. To the west, the Annara Chain slopes gently towerd
the Mekong River basin in lower Laos.
Economically, northern Annara is similar to Tonkin, with diverse
mineral deposits, but these are exploited to u less extent than
further north. Considerable forest reso'irces are concentrated in
this area, and the mountain regiors are zones of animal husbandry.
Southern Annam, now part of South Vietnam, is the principal zone for
the planting of Para 1 rubber (Hevea brasjliensis), especially where
red and gray soils are found. As in the north, the bulk of the
population in south Annam is concentrated in the river deltas, where
rice is extensively cultivated.
In South Vietnam the Mekong delta, covered with recent fertile
alluvium, is intensively cultivated to rice. This area has long
been regarded as the 'bread basket 1 of Vietnam. Another crop, second
in importance, is Par£ (Hevea) rubber, from plantation-grown trees.
Except for the lowland fertile plains of the Mekong and Tonkin
deltas, and intervening valleys, most of the land area of entire
Vietnam is not considered suitable for intensive cultivation. Much
cf the land is mountainous with rugged terrain, and elsewhere the
drainage is poor. As in Laos, Cambodia and Thailand, farming occupies
first place in the economy of entire Vietnam. Agriculture is basic
to other industrial and commercial activities.
Mekong Delta and Plain: The Mekong, sixth largest river in the
Far Kast, enters South Vietnam from Cambodia at about 1C! 0 K. longitude
and 11° N. latitude. Following a series of tortuous stream beds,
it flows southeasterly for about 12 miles (200 kms.) through several
channels in the delta region; to fall into the 3outh China Sea. This
flood plain is approximately 125 miles in width, dividing the ^reste
areas in the uplands, in the northeast, from about 2,000 square milesof
Mangrove forest along the coast. Some sections of the plain are
subjected during the rainy season to inundations by flood vaters, and
in parts are alternately covered by sea water, brackish and fresh
water.
This great plain extends northward for about 560 miles (896 kms.),
in places crowded to the coast line by mountainous cliffs, and elscr
where cutting ialand, following the basins of smaller stream;-;. Areas
along, the seacoast are exposed to wind-blovrn, fine, unite sand, which
covers fields, villages and highways. In former years windbreaks
and shelter-belts of Casuarina and Iftacalyptus trees were planted to
protect the beaches. These dune* are~shifting and cover everything
in thf.'ir path. Fields once planted to rice arc- now covered to a
72