43 



cheeking and give some protection from the elements. Such logs 

 could then be taken out when reached in the regular cutting and log- 

 ging operations. 



III. To girdle healthy trees in June to attract the beetles away from 

 timber that it is desired to protect, the girdled trees to be cut and 

 peeled, or placed in the water, in the ordinary practice of logging, 

 previous to the first of the following June. 



The use of girdled trap trees has the advantage of not only facili- 

 tating the destruction of the insects, but of attracting them away from 

 the matured timber that it is desired to leave standing for future cut- 

 ting. Still another advantage lies in the fact that trees may usually 

 be selected for this purpose which in the regular logging operations 

 could be cut and hauled to the streams within the limited time 

 required. The beetles which are attracted to the trees in this manner 

 may be disposed of by either of the preceding methods mentioned, so 

 that the onty additional expense over the regular logging operations 

 would be the cost of girdling. 



The infested spruce which can not be reached bj^ the extension or 

 adjustment of the summer and winter logging operations might be 

 felled and the bark removed from the infested portions of the trunks 

 any time between the first of August and the first of the following 

 June. The young stages of the insects and most of the adults would 

 thus be destroj^ed by the drying of the bark in summer, or by freezing 

 if removed in the winter. 



Another method would be to fell and " score" (by cutting through 

 the bark) the top of the infested portion of the felled trunks or logs 

 to let in the water, which, it is believed, would thus produce an 

 unnatural condition which would kill most of the insects. Experi- 

 ments are suggested to test the effects of water absorbed by the 

 unpeeled logs whether left in the woods or placed in the water. The 

 adoption of this method is not recommended, however, until experi- 

 ments prove its value and the conditions are found to be favorable for 

 its practical application. 



When the timber is dying rapidly in a given area of greater or less 

 extent, and the trouble is perceptibly spreading, and upon examina- 

 tion it is found that there are comparatively few insect enemies of the 

 beetle, either or all of the three methods should, under favorable con- 

 ditions for their practical adoption, prove of great service in prevent- 

 ing the undue multiplication of the pest and protecting the living 

 timber from attack. 



If the trouble seems to be on the decrease, and upon examination it 

 is found that a large number of natural enemies are operating on dif- 

 ferent stages of the spruce beetle, it may not be necessary to take 

 active measures for reducing their numbers. Indeed, under specially 

 favorable conditions for the enemies to operate, it may be best to do 

 nothing, for under such conditions an attempt to destroy the enemy 



