THE GENUS DENDROCTONUS. 



87 



lightning, broken, or felled by storms, landslides, etc., or injured by 

 fire. Unfavorable conditions for attacks on living timber will be 

 found in areas of vigorous young to matured growth under some 

 system of forest management which provides for the utilization of 

 the old timber and especially that injured by storm, lightning, fire, etc. 





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Fig. 49.— The mountain pine beetle: Tops of the trees shown in figure 48. (Original.) 

 METHODS OF CONTROL. 



Whenever it is positively determined that this species is killing 

 the timber and that the bark of living or dying trees contains living 

 broods, the principal groups of infested trees should be located and 

 marked during September, and then during the period beginning in 

 October and ending in the following July the infested bark should be 

 removed from the main trunk. The simple removal of the bark, 



