Bart V.] Sweet: On Air Seasoning of Indian Timbers. 
81 
CHAPTER X. 
Damage to Timber by Insects— by C. F. C. Beeson, M.A., F.E.S., 
D.Sc., Forest Entomologist. 
During the progress of the seasoning experiments described here, 
the borer-fauna of the timbers under experiment has been investigated 
by the Forest Entomologist partly from sample logs kept under obser- 
vation in the Insectary at Dehra Dun, and partly from field-work. 
The main object of the entomological side of the investigation was to 
determine the agencies at work, ?.e., the species of insects responsible 
for damage, rather than to discover immediate measures for their 
control. In fact, the experiments were devised by the Forest Economist 
to provide satisfactory remedies empirically, and, wherever successful 
methods have not been obtained, it is evident that no short-cut exists, 
and a special entomological investigation is required. The Insectary 
records have revealed the existence of hundreds of species of borers 
with which we were not previously acquainted, many of which are 
new to science, but, nevertheless, not necessarily new to commerce. 
Fresh ideas have been obtained on the distribution, and food habits 
of the borers and on the conditions under which timbers are liable 
to attack. Although the mass of data has not 3 ‘et been finallv worked 
up, a few conclusions having bearing on the practical question of 
timber seasoning can be made. 
In the following pages is presented a tentative classification of the 
different forms of damage by boring insects to which Indian trees are 
exposed. This should be read in amplification of the conclusions 
given below. 
t 
(1) Many species of forest trees are attacked by borers during 
the life of the tree and the damage is not perceptible until 
the seasoned timber is worked up. The existence of this 
form of damage may, therefore, cause a false interpreta- 
tion to be placed on the value of a particular method of 
seasoning. 
(2) The distribution of borers that are economic pests, is not 
necessarily coincident with the distribution of the trees 
attacked, and consequently a method of seasoning apph- 
cable to one locality is not necessarily reliable for another 
locality. 
(3) The season at which a tree is felled or girdled materially 
influences its hability to damage by a particular species 
of borer. The optimum or danger-free period cannot be 
expressed in general terms, but must be worked out for 
each, species of tree and each variation in its habitat. 
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