310 
The Philippine Journal of Science 
which are the dominant trees at low altitudes in the Philippines, 
also show similar rates of growth and have pointed out that the 
rates of growth of the dipterocarps in the Philippines are similar 
to those of Shorea robusta in India. 
The great density of the stands in the dipterocarp forests 
of the Philippines seems to account for the fact that the trees 
do not grow faster than those in the central hardwood region 
in the United States. Parashorea plicata, on Mount Maquiling, 
Philippine Islands (figure 1), growing in a rather open stand for 
a dipterocarp forest, shows much more rapid rates of growth 
than the average rate for dipterocarps. In Kurseong District, 
Bengal^ where the altitudes are low and moisture conditions 
favorable, Shorea robusta grows much more rapidly than in 
many other districts; the rates of growth being slightly faster 
than those for Parashorea plicata on Mount Maquiling. Caccia 
found that the rates of growth of Shorea robusta decreased at 
higher altitudes. Brown and Matthews also found that the 
same was true of trees in the dipterocarp forests of the Philip- 
pines. It is a well-known fact that in the tropics, as high 
altitudes are reached, the trees become very much dwarfed. 
This dwarfing is due to factors incident to high altitudes, but 
as the intensity of these factors varies at the same altitudes in 
different regions, it is not surprising that the degree of dwarfing 
is by no means proportional to the altitude. On Mount Maquiling 
at an altitude of 1,050 meters the trees are about 10 meters high, 
while on the Gedeh at an elevation above 1,300 meters. Doctor 
Koorders measured a tree 49 meters high. The forest on the 
Gedeh is more open than the average dipterocarp forest in the 
Philippines, which might be^expected to result in faster rates 
of growth. On the other hand, the elevation is considerably 
greater and this is probably accompanied by factors which re- 
tard the rates of growth. The large size attained by the trees 
would, however, indicate that this retarding effect is not nearly 
so great as in many other regions at the same altitude. 
SUMMARY 
The rates of growth of the trees on the Gedeh, in the limited 
number of cases measured, would indicate that these trees grow 
about as rapidly as the dominant trees in the Philippines, Shorea 
robusta in India, and hardwoods in the central hardwood regions 
of the United States. 
' Caccia, A. M. F. A preliminary note on the development of sal in 
volume and in money-value, Indian Forest Records 1 (1908) 1-238. 
