PROTECTION FROM OTHER AGENCIES 313 



one of the ambrosia beetles. The injury in reducing the 

 value of the lumber may amount in many localities to 

 from 25 to 75 per cent. 



Another class of injury is seen in the work of the 

 white pine weevil. This insect repeatedly attacks the 

 leading shoots of young white pine, causing a distorted 

 growth. The trees develop a crooked stem, and their 

 value is consequently very much reduced. 



Dying and dead trees are especially subject to attacks 

 by insects. The loss caused by them is principally in 

 the reduction in value of the product of the trees. In 

 some cases insects attack and kill trees weakened by fire 

 or some other cause, which otherwise might have recov- 

 ered and lived. 



There is a very close relation between forest fires and 

 damage by insects. It is believed that in some cases 

 when the past destruction of forests has been attributed 

 to fire, it has been primarily the work of insects. The 

 timber was first killed by the insects. The dead trees 

 furnished fuel for the later fires, which also killed all 

 young growth and retarded reproduction. The presence 

 of the dead trees which had been killed by insects, always 

 increases the menace from fire, not only by the added 

 amount of inflammable material, but also because of the 

 chance of their being struck by lightning and starting a 

 forest fire. 



When a forest has been burned, the final death of the 

 trees is often due to attacks by insects. The presence of 

 fire-scorched trees may cause a rapid multiplication of 



