Rocky Mountain Seedling Growth 105 



No damage is done the reproduction by grazing at present. 

 The cattle on the reserve confine themselves to the more abun- 

 dant alpine grass of the ' ' parks. ' ' Logging has done very little 

 injury, since little young growth occurred on cut-over tracts. 



Not enough humus is present to cause ground fires. Two 

 fires, five and nine years ago, respectively, destroyed consider- 

 able areas of dense young Engelmann Spruce. These were neither 

 surface nor crown fires, but what might be called brush fires.* 



Of Red Fir, Limber Pine, and Engelmann Spruce, the repro- 

 duction of the latter only is subject to what seems to be a serious 

 insect enemy, viz., the Spruce gall louse {Chermes spec.) It 

 attacks and deadens great numbers of growing points. When 

 the lateral branches are attacked, this may only serve to prune 

 the tree, and thus be a help rather than hindrance. But 

 frequently the leader is killed, robbing the tree of one to several 

 years' growth. 



Snow and ice do no appreciable damage. In the Red Fir only 

 were observed occasional specimens evidently broken by these 

 agents. One case was found where a freshet had deposited a 

 bed of gravel one foot deep in a stand of young Engelmann Spruce, 

 completely killing it. 



J. C. Blumer. 

 *Probably included in the new term "stand fire." (Bui. No. 61, 

 Forest Service. ) 



