Part I.] 
Troup : Teak Forests of Burma. 
23 
It should be noted that no allowance has been made for the time taken 
for a seedling to establish itself, or for the thickness of bark. 
3. Influence of Certain Factors on the Rate of Growth. 
We may now proceed to the consideration of a few miscellaneous 
facts brought out in existing working-plans, in so far as they concern the 
rate of growth. 
(1) Rate of growth in dry and in moist forest. 
The fact that most trees grow faster on rich than on poor soil hardly 
requires any demonstration. There are, however, certain interesting 
comparisons to be drawn from the data afforded by the working-plans, 
which we may deal with briefly. 
The Kyaukmasin reserve, referred to on page 20, is situated in the 
^ „ Pegu Yoma, and is surrounded by other 
Kyaukmasin Reserve. ° . . ^ 
reserves m which the exploitable age fixed is 
never higher than 180 years, while that of the Kyaukmasin reserve is 
fixed at 196 years : at first sight, therefore, it appears somewhat 
strange that the rate of growth in the Kyaukmasin reserve should be 
so much slower than in the surrounding reserves. The slow rate of 
growth, however, is explained by the fact that teak is there found only 
on the ridges and upper slopes, and never low down in the moister 
regions of the streams. This explanation is corroborated by the fact 
that in this reserve the average age of a tree 7 feet in girth, without 
allowances for the establishment of the seedling, is identical with that 
recorded for the Minbyin reserve, on poor localities, namely, 186 
years. 
It has been mentioned above that the rate of growth in the Ziyaing- 
„. . „ , _ Mehaw reserves of the Pyinmana Division 
is exceptionally slow, the average age of a 
tree 7 feet in girth, without allowances, being reckoned at 190 years. 
These reserves are situated to the east of the Sittang river, quite 
apart from any of the other reserves in the Pyinmana Division, but 
not far from the Gwethe reserve in the Toungoo Division, of which 
they practically form a continuation. The rate of growth in Gwethe 
is considerably faster. But whereas a large proportion of the ring- 
countings in the Ziyaing-Mehaw reserves were carried out in dry 
[23] 
