Indian Forest Records. 
62 
[Vol. VIII, 
the means of the girth-classes, the beehole index for 27*7 inches girth 
is found to be 5*6. 
The five top-broken trees felled in February, 1918 give the follow¬ 
ing figures :— 
Table 9. — Girth-Beehole Incidence in the Same Plantation at 20 years 
old , 1918. 
3 inch Girth- 
Serial 
Number of 
Girth in 
Number of 
Arithmetic 
Mean of 
Girth-class. 
Arithmetie 
Mean Beeholes 
Class. 
Sample 
Tree. 
inches. 
Beeholes. 
per Girth- 
class. 
13—15 
8 
15-3 
0 
15-5 
00 
19—21 
1 
20-5 
5 
20-5 
5-0 
25—27 
9 
250 
3 
250 
3-0 
31—33 | 
? I 
31-0 
31-0 
9 
10 
j 310 
9*5 
The arithmetic mean girth of this group is 24*6 inches and the arith¬ 
metic mean number of beeholes per tree is 5*4. As will be seen from the 
reduction values per annum for the first group of sample trees given 
in Table 10 below, the index of attack for 1918 is 0*4 beeholes ; this 
would give a beehole value of 5*4+0*4—5'8 for this group of trees had 
they lived a year longer. The close agreement between the indices of 
attack for the two groups of sample trees shows, that the results are not 
far wrong. As this degree of infestation is distinctly below the average 
for trees 21 years old, it is interesting to find that Quarry Siding planta¬ 
tion possesses the reputation of being one of the worst attacked areas 
in Burma. In 1905 when the plantation was 7 years old, Stebbing 
estimated that “ 40 to 50 per cent of the trees is the area inspected showed 
the present attacks or results of past attacks of the caterpillar.” The 
Report qn Forest Administration, Burma, for 1908-09, page 52 states 
that “ in the Mohnyin Reserve over 10 per cent of the older trees have 
been attacked and in plantations not more than 20 per cent have escaped.” 
The Working Plan for the Mohnyin Reserve, 1910, page 6 emphasises 
the abundance of the borer and the great damage done in Quarry Siding 
plantation. In 1914 the writer visited this plantation and estimated the 
current year’s attack at 15 per cent, and pointed out in the Report on 
the Beehole Borer Enquiry for 1914, that Quarry Siding plantation 
appeared to possess an undeserved notoriety for beeholing. If the 
data in Tables 8 and 9 are examined it will be seen that in 1914 
only 4 trees out of 24 or 16*6 per cent were attacked, an unexpected 
confirmation after a lapse of 5 years. 
[ 290 ] 
