Rocky Mountain Seedling Growth 99 



sparingly near mountain tops and on exposed high ridges. The 

 Alpine Fir is curiously restricted to north slopes in the upper 

 North Cheyenne Basin. Here it forms as much as five per cent 

 in some very dense young Engelmann Spruce growth. Age 

 counts prove that it came in after the fire of 50 years ago, and 

 four to six years ahead of the Spruce. The White Fir and its 

 reproduction are limited to altitudes below 9000 feet, and here 

 mainly to the southeast part of the reserve. Here the young 

 growth, in a few old burns, makes one-half to two-thirds of the 

 stand. The young Bull Pine, or Rock Pine, is limited to the 

 lower South Cheyenne Basin, so far as considerable numbers are 

 concerned. Very sparingly is it found throughout, and almost 

 co-extensive with the Red Fir zone. 



The Red Fir makes the most abundant and most generally 

 distributed reproduction below the 9000-foot limit. The Limber 

 Pine is the tree which, barring accidents, will eventually thickly 

 dot nearly all south, east, and west slopes between 9000 and 

 11,000 feet. The process of recovery from past denudation, 

 however, will be very slow at best. The Engelmann Spruce in 

 the number of its young trees outnumbers those of all other 

 species combined. It is by far the best plant factor to conserve 

 snow and water that these mountains possess. Following creeks 

 as far down as 7000 feet, its ideal home is on northerly slopes 

 next timberline, at an altitude of 11,000 to 11,500 feet. 



The period of greatest mortality could not be definitely deter- 

 mined because the reproduction is not represented by all ages. 

 It is safe to say, however, that this period for all species would 

 i^all within the first three years of the seedling's life. 



Seeds often germinate on decaying logs, on thick, moist duff, 

 or in other less favorable situations. Presently these places dry 

 out, and the seedlings perish for want of moisture. Or, particu- 

 larly in case of Engelmann Spruce, they may start in genial 

 shade, and by removal of the shading object or shifting of the 

 sun's course, be exposed to the murderous rays of the latter. 

 Or, they may find every favorable condition but mineral soil, 

 and die for want of mechanical support and plant food. 



Not enough infant seedlings were observed to determine under 

 what conditions they best germinate and grow. They are rare 

 things in the region covered. In the case of Engelmann Spruce 

 on favorable locations, no harmful mortality takes place, for 

 seedling growths persist in very great density to 40 years of age. 



