Part III.] Beeson: Beehole Borer of Teak. 77, 
Table 18.— Girth-Beehole Incidence in an 18 year-old Plantation, Kaing 
Pyinmana, 1919. 
3 Inch 
Girth- 
Class. 
Serial 
No. of 
Sample 
Tree. 
Class. 
Girth 
in 
Inches. 
Number 
of 
Beeholes. 
Arithmetic 
mean of 
Girth- 
Classes. 
Arithmetic 
mean 
Beeholes 
per Girth- 
Class. 
r 
10 
s 
19 
0 
19—21 .J 
12 
15 
D 
d 
20 
20 
2 
0 
200 
T-0 
l 
13 
d 
21 
2 
22—24 
16 
d 
23 
2 
23 0 
*2-0 
25—27 
28—30 
14 
11 
D 
d 
27 
28 
6 
2 
27- 0 
28- 0 
60 
2-0 
The position of the trees does not appear to produce marked 
differences in the incidence of attack. Nos. 10, 11, 12 were on the 
badly drained valley-flat, 13 and 14 on the slope and 15 and 16 at the 
junction of the flat and the slope. 
The arithmetic mean girth of the sample trees is 22‘57 inches ; the 
arithmetic mean number of beeholes per tree is 2-0 ; the girth of a normal 
mean tree 18 years old is 24-25 inches, and the number of beeholes for 
this tree obtained from the girth-beehole graph is 2’5. This index of 
attack indicates an infestation slightly less than the average for all 
sample plots. 
The annual incidence is given in the following table. 
Table 19 .—Annual Incidence in an 18 year-old Plantation, Kaing, 
Pyinmana, 1919. 
1 
1901— 
1907. 
1908. 
1909. 
1910. 
1911. 
1912. 
1913. 
1914. 
1915. 
1916. 
1 1917. 
i 
1918. 
ua 
-<j 
H 
O 
H 
Com¬ 
bined 
attack 7 
trees. 
0 
1 
1 
3 
1 
1 
0 
1 
2 
1 
2 
1 
14 
Reduced 
values. 
0 
0-18 
0-18 
0-53 
0-18 
0-18 
0-00 
0-18 
0-36 
0-18 
0-36 
0-18 
2>5 
These data are plotted in the annual incidence graph as those of a 
mean tree of 24*25 inches girth with a total of 2-5 beeholes. It will 
be seen that the incidence remains practically level and is not visibly 
affected by fires or by thinnings. This plantation and the next, No. 5 
of 1899, were examined at the suggestion of Mr. L. C. Davis, Divisional 
Forest Officer, that they might possibly contrast the effects of fire- 
protection and departmental burning. 
[ 305 ] 
