38 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
control, such as fires, tornadoes, floods, droughts, and even business 
depressions, and then extensive losses are unavoidable. For the re- 
duction of insect losses to forest products, prevention of damage, 
rather than control, should be the aim. In most cases this may be 
accomplished by efficient management of logging and milling opera- 
tions, by the proper inspection “and handling of stored materials, by 
the use of preservatives in protecting wood in contact with the ground, 
and by the proper designing and sound construction of buildings. 
PREVENTING DEFECTS IN LIVING WOOD 
Defects in the wood of living trees, such at pitch pockets, pinholes, 
worm and grub holes, pith flecks, gum streaks, ring distortions, and 
black check are not reaclily preventable. However, with more inten- 
sive forest practices, such as selective cuttings and thinnings, in opera- 
tion, it should be possible to remove from the forest the trees that 
serve as brood trees for the injurious insects and thus hold down the 
infestation to a low degree. Pitch pockets resulting from the attack 
of the turpentine borer can be largely prevented, as explained under 
discussion of that insect (p. 193). Control of forest fires, thus pre- 
venting fire scars at the bases of trees, helps to prevent pinholes caused 
by ambrosia beetles. Grub holes and worm holes caused by such wood 
borers as Prionoxystus, Parandra, Goes, and Romaleum, and pinholes 
caused by the Columbian timber beetles, the true timber worms, and 
certain ambrosia beetles, can be avoided only by removing the brood 
trees from the forest. 
These defects lower the grade and render the material useless for 
certain purposes, but frequently it is possible to use damaged material 
for purposes that do not call for perfect lumber. For “example, nm 
localities where damage by timber beetles is prevalent, white oak that 
could have been used for barrel staves may be cut into lumber or 
dimension stock. Often wood containing an abundance of defects 
hke knots, ring distortions, gum streaks, and pith flecks, can be used 
for specialities where the defects become a character of added value, 
as for rustic slabbing or interior finish (Snyder, 389). 
PROTECTING GREEN LOGS 
Green logs are very attractive to ambrosia beetles and wood borers, 
and under ‘optimum conditions beetles may be found boring into the 
wood within a few hours after a tree is felled. The surest means of 
preventing damage by these insects is by keeping the logs moving 
promptly from the woods to the saw; ; and if it does become necessary 
to store the logs for any length of time, they should be placed in a 
stream or millpond, preferably where direct sunlight can strike the 
tops of the floating logs. The old adage “a stitch in time saves nine” 
is a key to the prevention of borer and ambrosia beetle attack on saw- 
logs and lumber. 
Depending on the season, temperature, and moisture conditions, and 
the species of insects involved, there is usually an interval of a week 
to a month or more between the felling and the time when green logs 
must be sawed if they are to be safe from insect attack. In many 
instances it takes the young borers some time to penetrate the bark 
