INSECTS INJURIOUS TO FOREST TREES 341 



This injury is best prevented by prompt utilization of timber within a few 

 months after it is dead or found to be past recovery; by removing the bark 

 from the merchantable portion of the trunli within a few weeks after the trees 

 are dead; by felling the trees and placing the unbarked logs in water; or by 

 the adoption of a system of forest management which will provide for the 

 prompt utilization of all trees dying from any cause. 



INSECT INJURIES TO FOREST PRODUCTS 



Damage is caused by various species of insects which are attracted by the 

 varying conditions prevailing at different stages during the process of utilizing 

 the forest resources from the time the trees are felled until the logs are 

 converted into the crude and finished product, and until the latter reaches the 

 final consumer or until after it is placed in the finished article or structure. 

 As a result additional drains are made upon the timber to meet the demands 

 for higher grades of lumber and for other supplies to replace those injured or 

 destroyed. Dr. Hopkins states that from his personal investigations of this 

 subject it is evident that the damage to forest products of various kinds from 

 this cause is far more extensive than is generally realized. This loss differs 

 from that resulting from insect damage to standing timber in that it represents 

 more directly a loss of money invested in material and labor. 



Injury to crude products, such as round timber with the bark on, poles, 

 posts, mine props, saw-logs, etc., is caused by the same class of insects. The 

 damage is especially severe when material is handled in such a manner as to 

 offer favorable conditions for attack, as when the logs are left in the woods on 

 skidways or in mill yards for a month or more after they have been cut from 

 the living tree. Round-headed borers, timber worms and ambrosia beetles are 

 all serious enemies of timber under such conditions. 



Ambrosia beetles and other wood borers also attack freshly sawed hardwood 

 placed in close piles during warm, damp weather during the period from June 

 to September, and wood borers injure lumber and square timbers of both soft 

 and hardwoods with the bark left on the edges, the borers hatching from 

 eggs deposited in the bark before or after the lumber is sawed. Seasoned 

 products in yards and storehouses suffer from the powder-post beetle, and old 

 hemlock and oak tan bark is often so badly damaged by various insects which 

 infest dead and dry bark that in some tan yards as much as 50 to 75 per 

 cent of the bark that is over three years old is destroyed. The greatest loss 

 of finished hardwood products such as handle, wagon, carriage and machinery 

 stock is caused by powder-post beetles, and these, together with white ash or 

 other wood-boring insects, follow the product into its finished state in imple- 

 ments, machinery, wagons, furniture and inside finish. 



The control and prevention of such injuries as these offer less difficulties 

 than that in many other branches of the general subject of forest insect control. 

 In most cases the principle of prevention is the only one to be considered, 

 since the damage is done soon after the insects enter the wood so the wood 

 cannot be repaired by destroying the enemy. A great deal depends upon the 

 proper degree of moisture and the period of danger varies with the kind of 

 timber and the time of year it is felled. This applies to crude products, and, 

 in a measure, to manufactured seasoned products. The general principles of 

 control are on the same lines as those indicated in the other sections, and may 

 be summed up in the general statement of prompt utilization and care in the 

 conditions of stoi-age. In utilized products material may also be treated with 

 preservative. 



