Figure 11. — Extensive areas of the Sleeping Child Bum heoame stocked so heavily that 



thinning has been required to promote tree growth. 



reasonable to speculate that the faster growing genotypes are being destroyed before 

 the lodgepole pine trees can restock the area. Trees as young as 62 years have sus- 

 tained beetle infestations so that selection sometimes begins early in the life of 

 these stands. If wildfire strike's the stand before the selection process has pro- 

 gressed too far and seeds from serotinous cones are released to regenerate the stand, 

 such selection may not be of much consequence. However, if fires or other stand- 

 regeneration processes do not occur before the stand reaches an advanced stage of 

 depletion the selection is likely to have more effect. 



Some Secondary Effects 



Populations of secondary beetles, such as Ips pini Say, build up in harmony with 

 mountain pine beetle infestations (Gibson^). Emerging from trees either killed or 

 weakened by mountain pine beetles, these secondary beetles may be present in sufficient 

 numbers to kill trees. The secondaries attack principally smaller trees and therefore 

 do not have the devastating effect on the stand that the mountain pine beetle does. 

 In some instances, the tree killing by Ips beetles may amount to a thinning of the 

 smaller residual trees. 



Windthrown beetle-killed trees often cause destruction or damage to trees in the 

 succeeding understory. The beetle-killed trees begin to topple within 5 years after an 

 infestation has declined (Flint 1924) and such windthrow may continue for 10 or more 

 years following the end of the infestation according to Gibson. 2 Gibson observed heavy 

 damage among the trees in the very small diameter classes and even among seedlings. 



17 



