27 



utilizing some method of management specially adapted to the pre- 

 vailing conditions in each case, which will reduce the number of the 

 depredators or otherwise prevent losses. 



SOME PRACTICAL RESULTS. 



A few examples ma}^ be given of the practical application of a 

 knowledge of some of the principal facts in the life history, as follows: 



The recent determination that the tanbark-destroying insects do not 

 attack the stored bark until it is two or three years old suggested a 

 simple method of preventing losses. 



The determination that the spruce-destro3nng beetle attacks only 

 the larger trees, and that the beetles could be attracted to trees 

 hack-girdled during the proper period in June, suggested important 

 methods of forest management and lumbering operations, which will 

 contribute to the elimination of trouble from this pest. 



Girdling and timber-cutting experiments have demonstrated the 

 possiblility of preventing losses from the ravages of insects and wood- 

 destroying fungi by girdling and cutting timber when the ph3^siolog- 

 ical conditions are such as to render the l^ark and wood unattractive 

 to the depredators or unfavoral)le for their destructive work. 



A knowledge of the habits and characteristic work of bark-infesting 

 insects in living, dying, and dead trees furnished conclusive evidence 

 that a large amount of healthy, uninfested, living timber had been 

 cut in the Black Hills forest reserve, where it was intended that none 

 but trees infested by the pine-destroying beetle or those killed by it 

 or other causes should be cut. It was also demonstrated that a knowl- 

 edge of the principal facts relating to the primary and secondary insect 

 enemies of the pine of this region would facilitate the drawing up of 

 timber-cutting contracts which would avoid nmch future trouble and 

 litigation relating to the interpretation of references to insect and 

 insect-killed timber. 



Facts determined relating to the habit of the pine-destroying beetle 

 of the Black Hills and the relation of other insects and fungi to the 

 trees injured and killed by it suggested methods of future management 

 which would prevent the loss of much timber, and contribute to a 

 better public appreciation of the importance of Government forest 

 reserves and the adoption of scientific forestry. 



The facts which have been recently determined from special investi- 

 gations of the troubles caused l)y the destructive pine bark-beetle, the 

 chestnut timber worm, the oak timber worm, the giant root-borer, and 

 a number of other principal enemies of Eastern forest trees have made 

 available a fund of information which it is believed can be used to 

 special advantage in formulating future plans for the management of 

 Eastern forest reserves, systematic forestrj^ work, conservative lum- 

 bering, etc. 



