Native Vegetation 
4i 
fringes of pinyon pine-juniper on stony outcrops, or where the soil 
is shallow and underlaid by rock. 
Sagebrush seldom occupies a habitat where soil moisture is 
near the surface. Furthermore, typical sagebrush soil is well- 
drained, low in water content, and always practically free of 
“alkali.” 
The behavior of the native herbaceous plants in the sagebrush 
steppe suggests what will be the behavior of cultivated herbs un¬ 
der similar conditions. The surface soil, upon which herbs are 
dependent for their water, becomes exhausted of water in early 
summer, and the native herbs mature quickly before complete ex¬ 
haustion takes place. From the middle of July on through the rest 
of the growing season there is little available water in the soil for 
shallow-rooted plants. 
Climate of Sagebrush Steppe .—The mean annual precipitation 
on Colorado sagebrush areas ranges from under 10 inches to 17 
or 18 inches. The community is most typical, however, in those 
sections with less than 15 inches of precipitation. The average 
amount of 11 stations is 13.1 inches. (See Table 15). Shallow- 
rooted short grasses, such as dominate the Great Plains, could not 
flourish in a habitat with rainfall distributed throughout the year 
as it is in shrub-steppe. In fact, the distribution of the rainfall 
throughout the year is one of the most important climatic differ¬ 
ences between these two formations of plants. The precipitation 
is quite evenly distributed over the different seasons (Fig. 10). 
There is a winter snowfall. Moreover, snows of the Western 
Slope lie on the ground for longer periods than they do on the 
TABLE XV.—PRECIPITATION IN SAGEBRUSH SHRUB-STEPPE. 
Station 
Altitude 
County 
Mean Annual 
Total from Oct. 
to May (inc.) 
% from Oct. 
to May (inc.) 
% from June 
to Sept, (inc.) 
Mean Annual 
Snowfall 
Delta . 
.. 4965 
Delta . 
8.38 
4.96 
58.95 
41.05 
14.0 
Glenwood Springs . . 
.. 5823 
Garfield . 
12.12 
8.11 
66.91 
34.09 
53.0 
Grand Junction. 
.. 4602 
Mesa . 
8.36 
5.42 
65.09 
34.91 
17.0 
Gunnison . 
.. 7670 
Gunnison . 
11.09 
5.65 
50.94 
49.06 
49.0 
Kremmling . 
7337 
Grand . 
16.79 
10.22 
61.00 
60.90 
11.0 
Lay . 
. . 6190 
Routt . 
12.68 
8.96 
70.66 
29.34 
67.2 
Montrose . 
.. 5811 
Montrose . 
9.91 
5.94 
59.94 
40.06 
28.0 
Rangely . 
.. 5050 
Rio Blanco .... 
12.74 
7.67 
60.20 
39.80 
49.0 
Redvale . 
.. 6300 
Montrose . 
15.35 
9.22 
60.07 
39.93 
28.3 
Sapinero . 
.. 8125 
Gunnison . 
18.69 
12.99 
60.50 
30.50 
12.0 
Wa lderi 
8050 
Jackson . 
7.94 
• 
29.7 
Average. 
13.10 
7.91 
62.33 
37.64 
32.6 
