28 Indian Forest Records. [Vol. III. 
eastern slopes are more gentle. In the Pegu Yoma forests of Pyinmana, 
on the other hand, the strata dip at various angles and in different direc¬ 
tions, with the result that the ridges and spurs ramify in all directions, 
the general trend of the central Pegu Yoma ridge being north and south 
and that of the main subsidiary ridges east and west. 
So far as present information goes, therefore, the topography of the 
country and the local climatic conditions and other factors, appear to 
have so much influence on the rate of growth, that aspect must be 
regarded only as one of many factors which have to be reckoned with. 
(4) Variations in rate of growth. 
Considerable differences in the rate of growth of teak trees in the 
same locality are to be noticed almost universally, and as Mr. S. Carr 
remarks in the Minbyin working-plan with respect to the rate of growth, 
“ Not only does it differ in different localities, but trees growing almost 
side by side frequently exhibit widely differing rates of growth. In 
such cases the difference must be due to causes other than the factors 
of the locality, such as fire, suppression, or injury from other causes.” 
In the teak forests of Burma suppression, whether by trees, bamboos, 
or climbers, is undoubtedly the most potent factor in causing this 
difference in the rate of growth of trees growing in similar localities, for 
a light-demanding species like the teak will stand little shade or inter¬ 
ference with its crown, while it responds readily to any opening of the 
canopy, whether natural or artificial. 
Mr. Carr has drawn attention, in the Yeni working-plan, to certain 
periodic interruptions in the rate of growth of teak, a phenomenon which 
is observable in many other localities. To quote Mr. Carr’s own words : 
44 For some cause or other which is not necessary to discuss here, the 
growth of a large proportion of the trees, as exhibited by the annual rings 
on stumps, has been very much retarded at several periods of their 
lives. The growth, after proceeding normally for a time, suddenly 
becomes abnormally slow, so much so that the rings are so close 
together as to be difficult, and in some cases impossible, to count 
with certainty. This period of slow girth would extend over a number 
of years and the growth would then again become normal. As many as 
four of these cycles of slow growth were noticed on some of the larger 
stumps, but the general number, where they existed at all, was two or 
three, and if they can be prevented altogether, it is obvious that in the 
future the age of a tree of 7 feet in girth will be considerably less than 
ft has been in the past.” 
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