areas are subsequently burned ocff by surface fires and are then gen- 

 erally referred to as fire wounds. The further damage to the ex- 

 posed wood by successive fires, decay, and insects often results in a 

 total loss of the best portion of the tree, or a reduction in value of the 

 lower section of the trunk of from 10 to 50 per cent. These and 

 similar wounds in the bark of trees, including those caused by light- 

 ning and by the uncovering and exposure of the wood in turpentin- 

 ing, offer favorable conditions for the attack of the turpentine borer, 

 the work of which, together with that of two or three others with 

 similar habits, is very extensive, and causes losses amounting to from 

 10 to 50 per cent of the value of the wood of the best part of the trees 

 thus affected. 



The white fine weevil. — The abnormal development of white pine 

 trees as the result of successive attacks on the terminals of the sap- 

 lings and 3"oung trees by the white pine weevil is an element of loss 

 of considerable importance, especially in mixed stands and in open 

 pure stands of this timber. The value of such trees is reduced from 

 20 to 50 per cent below those of normal development, and there is an 

 additional loss from the effect of their spreading branches or crowns 

 in the suppression or crowding out of trees which would otherwise 

 occupy the space thus usurped. 



There are many other examples of insects which damage the wood 

 and bark of living trees, but those mentioned should be sufficient to 

 demonstrate the importance of insects in this relation. 



CONTROL OF INSECTS WHICH CAUSE DEFECTS IN LIVING TIMBER.<^ 



The class of insects which cause defects in the wood of living timber 

 can be controlled to a greater or less extent, depending upon local con- 

 ditions, and a large percentage of the losses prevented through the 

 adoj^tion of certain requisite details in forest management, among 

 which the following are esiDCcially important : 



(1) The utilization of all of the defective and infested timber 

 that will pay expenses for manufacture into merchantable products, 

 such as lumber, cordwood, etc. 



(2) The burning of infested timber and waste material not avail- 

 able for use, including dead standing and fallen timber, to remove 

 the breeding places of insects like the oak timber worm and the 

 chestnut timber worm, which go from the dead to the living timber. 



(3) The prevention of wounds of any kind in the bark of living 



trees. 



— — — — 1 



« For uietbods of controlling the locaist boi-er and white pine weevil, see 

 Circulars S3 and 00, respectively, of the Bureau of Entomology, U. S. Depart- 

 ment of Agriculture. 

 [Cir. 126] 



