Vegetation of Southeast Asia Studies of Forest Types 1963-1965

woodland, from such features as the varying hue and density of their
foliage; as well as to determine air-to-ground visibility in this
special type of forest, which is of considerable importance, militarily,
as a potential staging area. This aerial survey of Mangrove
forest was concentrated around Khlung, Trat and the island of
Kohchang. We then continued northward over Moist Evergreen forost,
covering the mountain ranges between Thailand and Cambodia, in the
direction of Aranyaprathet, Soon after leaving Aranyaprathet we
had a mishap, when the tip, about 8 inches long, of one of the propellers
broke off, but fortunately it did not damage the fuselage.
We flev eastward, on a single motor, for a considerable distance
over open Dipterocarp forest unlil we reached Ubon, where we landed
safely. On the return journey we passed again over large extensions
of Dipterocarp forest, in the east, and the upper Moist Evergreen
and Lower Montane forests in the ;Chao Yai area of Kovat.
On February 3> we flew in the CAT spray plane, piloted by Captain
Herzig, from Bangkok over the large Hill Evergreen Moist forest in
the Khao Yai National Forest, and Dipterocarp forest extending beyond
Konkaen, in the Korat plateau.
On February 6, we continued over the Pine forest characteristic
of the high plateaus around Loei, in the northeast, Teak forest in
the region of Lomsak and Phetchabun, and finally southward across the
central plain to Bangkok.
On February 9, accompanied by Dr. Robert A. Darrow, in charge of
studies being conducted with defoliants by the Biological Laboratory
at Fort Detrick, Maryland, an aerial inspection ras made of the test
site near Pranburi, upper Peninsula, to observe the effects of chemicals
on vegetation, especially from the standpoint of desiccation, plant
survival and regrowth, and as a means of improving air-to-ground visibility.
The weather and visibility during all flight periods were good to
excellent. However, from early February until the end of the dry
season visibility from the air is reduced somewhat, because of a heavy
pall of blue-gray haze, rising from forest fires, to clear patches
for tilling, and the burning of straw in harvested rice paddies, which
hovers constantly over the countryside.
Comments: Photographs, several of vViich are reproduced in this
Report, were taken with hand-held cameras. Black-and-white panatomlc-x
and panchromatic film (with x2 yellow filter), as well as colored
film (Kodachromc- K-2 with haze filter) were used for comparative pui>pose.
It was found that, as a rule, color film gives a better rendition
than black-and-white; a more satisfactory resolution in bringing out
densi-cy and hue of the foliage; color of bark; size and form of crowns,