20 ABSAEOKA DIVISION OF YELLOWSTONE FOREST EESEBVE. 



of the region. Rarely they lie singly; usually they are in groups of 4 to 7 or 

 more, connected by little rivulets. Sometimes they are fringed by narrow 

 belts of timber or lines of brush, but more frequently their surroundings are 

 bare rocks, or steeply sloping tracts of alpine meadow down to the water's edge. 

 They are gradually disappearing, in part by silting^ from adjacent slopes, and in 

 part by deepening of their outlets and consequent drainage. A large number 

 have disappeared in this way and now form tracts of merely marshy ground. 



The lakes of the reserve are of great importance, in view of future plans for 

 water storage. Scores of the small ones could be turned into large lakes by moderate 

 and not costly embankments across their outlets. All the streams heading in them 

 are feeders to rivers whose waters are utilized for irrigation in the agricultural 

 districts in the lowlands, and there can scarcely be any doubt that in course of 

 time these natural reservoirs will be enlarged and utilized to the utmost. 



FOREST COIVDITIOXS. 



COMPOSITION AND RANGE. 



The forest in the reserve is almost wholly coniferous, and is made up of the 

 following species: 



Limber pine. ^ Pinua flexilis 



Lodgepole pine Pinus murrayana 



Yellow pine. - Pinus ponderosa 



White pine Pinua monticola 



White-bark pine Pinus albicaulis 



Red fir Pseudostuga taxifolia 



Subalpine fir ^ ., Abies lasiocarpa 



Engelmann spruce Picea engelmanni 



The deciduous trees are represented by aspen, cottonwoods, various species of 

 arborescent willows, hawthorn, wild cherry, and service berry. The species of trees 

 with diameters exceeding 3 inches at the base occur in the following proportions: 



Cbmpogiiion of forest in Ahscuroha division of Yellowstone Reserve, including trees of all species with basal 



diameters of 3 inches and upward. 



J Per cent. 



Limber pine 2. 3 



Lodgepole pine 45. 6 



Yellow pine 005 



White pine 0002 



White-bark pine 5. 3 



Red flr , : 12. 2 



Subalpine fir 11. 1 



Engelmann spruce 21. 8 



Aspen and cottonwood 1. 6 



Other species of broad-leafed trees, less than 05 



