INSECT DEPREDATIONS IN NORTH AMERICAN FORESTS. 83 



the disseminated information has been extensively utilized and that 

 it has been worth many millions of dollars toward eliminating the 

 losses and reducing the drain on the limited supply of the kinds of 

 timber required to replenish the damaged and destroyed material. 



The army and navy stores of handles, tent poles, wheelbarrows, 

 oars, and many other hardwood articles have suffered severely from 

 powder-post damage, involving an enormous loss, but the carrying 

 out of the information already supplied has evidently contributed 

 greatly toward the elimination of this source of loss to the Gov- 

 ernment. 



Tan Babk. 



Damage to hemlock and oak tan bark by the class of insects which 

 in some cases has been so destructive to these products in the past can 

 be easily prevented without cost, as follows: 



(1) Utilize the bark within three years from the time it is taken 

 from the trees. 



(2) Prevent the accumulation in the yards and store-sheds of old 

 bark and waste material in which the insects can breed. 



These simple methods have been extensively adopted since their 

 recommendation in correspondence and publications between about 

 1894 and 1904, and afford one of the most striking examples of the 

 value of expert information on the peculiar habits of insects and of 

 how millions of dollars can be saved without cost through a simple 

 adjustment in methods of utilization. 



Utilized Products. 



Damage and loss from insect injuries to timber and other woodwork 

 in structures of various kinds, to telephone and telegraph poles, posts, 

 railroad ties, mine props, etc., can be prevented to a large extent 

 through the adoption of the proper methods of management or of 

 treating the material with preservatives before and after it is utilized. 



TIMBERS AND WOODWORK IN STRICTURES. 



Injuries to timbers and woodwork in dwellings, outbuildings, 

 bridges, etc., by powder-post insects can be prevented as follows: 



(1) Use nothing but heartwood for the concealed parts most liable 

 to damage. 



(2) If it is necessary to use all or part sapwood material, attack 

 can be prevented by treating the sap portions with kerosene, coal tar, 

 creosote, or linseed oil. Facilities for future treatment can be pro- 

 vided wherever the rough or finished woodwork is exposed, as in 

 outbuildings, bridges, etc., if care is taken to expose the sapwood 

 portions. 



