Native Vegetation 
3 i 
3. Chaparral or brushland (thicket). Oakbrush, buckbrush, 
willow thicket, chokecherry, thornapple, mountain mahogany, etc. 
4. Coniferous woodland. Pinyon pine and juniper woodland. 
5. Coniferous forests. 
a. Yellow pine-Douglas fir forest. 
b. White fir forest. 
c. Lodgepole pine forest. 
d. Engelmann spruce-balsam fir forest. 
It is realized that some of the above groups, particularly 
greasewood shrub-steppe, and chaparral, have a wide range of cli¬ 
matic conditions, and are called forth by local factors to a large 
degree, but they are such prevalent types of vegetation in the state, 
that they are included here and the range of their factors given. 
Altitudinal Zones of Vegetation in Colorado .—Altitudinal 
vegetation zones or belts in the state are quite clearly recognized. 
As one travels from the sage plains of western Colorado, or from 
the grass plains of the eastern section of the state, to the crest of 
the Continental Divide, he passes through quite distinct and often 
sharp belts of vegetation. Realizing the changes in the supply of 
moisture, in the temperature, and in other environmental factors 
that accompany an increase in altitude, one is led to suspect that 
the different vegetation belts are a response to these factors, and, 
furthermore, that the presence of this or that dominating plant 
group might be corielated with crop possibilities. At least, it is 
believed possible to establish the broader and more general corre¬ 
lations. 
NORTHEASTERN COLORADO 
1. Plains (grass-steppe or short grassland). Up to 6,000 feet. 
2. Chaparral or brushland of chokecherry, thornapple, moun¬ 
tain mahogany, etc. A narrow, interrupted belt. 
3. Yellow pine-Douglas fir zone. 6,000-8,000 feet. 
4. Lodgepole pine zone. 8,000-10,000 feet. 
5. Engelmann spruce-balsam fir zone. 10,000-11,500 feet (tim¬ 
ber-line). 
6. Alpine zone. Above timber-line. 
SOUTHEASTERN COLORADO 
1. Plains. Up to 5,500 or 6,000 feet. 
2. Pinyon pine-juniper zone. 5,500 or 6,000-7,000 feet. Oak 
chaparral is frequently an associate. 
3. Yellow pine-Douglas fir zone. 7,000-8,500 feet. 
