XIV. 5 
Yates: Growth of Hevea Brasiliensis 
517 
has not been found practicable to apply any correction for this 
difference due to height of measurement; but when comparing 
the girth of trees measured at different heights, the fact should 
be borne in mind that such difference exists and that it increases 
with the size of the tree. 
In fig, 1 is plotted the average circumference of trees of the 
various ages measured, and from this curve the average circum- 
ference of trees from 1 to 10 years old has been calculated. The 
results obtained in this manner are given in Table XI. 
Table XI . — Diameters attained by average trees in Basilan. From 1 to 10 
years old with increment. 
Ag’e in years. 
Circum- 
ference. 
Incre- 
ment. 
cm. 
cm. 
1 
10.3 
10.3 
2 
18.7 
8.4 
3 
27.2 
8.5 
4 — 
35.6 
8.4 
5 
44.0 
8.4 
6 - 
52.4 
8.4 
7 . 
60.9 
8.5 
8 
69.4 
8.5 
9 . 
77.9 
8.5 
10 
86.5 
8.6 
Age in months. 
Fig. 1. Comparison of the growth of Hevea brasiliensis in the Philippine Islands with 
that in Ceylon and Malaya. 
