46 
The Colorado Experiment Station 
Pig. 15.—Cultivated sagebrush land in vicinity of Steamboat Springs. 
Alfalfa, potatoes, small grain, timothy and alsike clover are grown. 
Mountain mahogany is generally distributed throughout Colo¬ 
rado in the foothills and on the lower mesas. It clothes dry, rocky 
hill-slopes, indicating arid conditions that are incapable of being 
utilized agriculturally. Climatically, it belongs to the western 
yellow pine zone. Skunk-brush (Rhus trilobata) is a common as¬ 
sociate. 
The “canyon thicket”, of chokecherry, thornapples, ninebark, 
etc., is found at the mouths of canyons at low elevations, and is 
indicative, generally, of a climate intermediate between that of 
the Great Plains and the yellow pine zone, or between the “sage 
plains” and the zone above it. 
Chokecherry (Primus melanocarpa ) forms a chaparral growth 
in western Colorado, alternating on the slopes with oakbrush, 
buckbrush, and other shrubs of the yellow pine zone. Its distribu¬ 
tion and agricultural relations are similar to those of the scrub oak 
chaparral. 
Common Juneberry (Amelamchier alnifolia ) makes a dense 
thicket growth in sections of western Colorado, at elevations much 
the same as occupied by scrub oak, buckbrush and chokecherry. 
PINYON PINE-JUNIPER WOODLAND ZONE 
Distribution and Vegetation .— Pinyon pine (Pinus edulis ) and 
the one-seeded juniper (Juniperus monospernm) form a rather 
distinct belt of vegetation which occupies a position just below 
the yellow pine zone. The general distribution of this belt is 
shown in Fig. 16. It is seen to form a belt along the lower foot¬ 
hills in the section south of Colorado Springs, and running up the 
