6o 
FRANCIS RAMALEY 
Climate and Soil 
The climate of the area under consideration is cold, corresponding to 
that of Labrador, the Hudson Bay country, and southern Greenland. 
The timber limit is about 11,500 feet; lakes above this datum I shall speak 
of as alpine, those between this altitude and that of 10,000 feet as subalpine. 
At Corona, on Rollins Pass, at an altitude of 11,660 feet, a government 
weather-bureau station was maintained (3) for a number of years. Here 
the mean annual temperature was found to be 26 degrees F. and the pre- 
cipitation 43.7 inches. These figures may be taken as representative of the 
alpine region in this part of Colorado, although the tops of the higher 
peaks are, no doubt, colder and wetter. Throughout the alpine district 
there is frost every month of the year and in many places nearly every day. 
*For the subalpine zone only very incomplete records are available, but 
it is likely that at 10,000 feet the mean annual temperature is about 36 
degrees F. and the precipitation 30 inches. The period without frost does 
not exceed three or four weeks even in favorable seasons. Precipitation is 
always ample during the growing period. There are frequent light showers 
during July and August (8). In table i a comparison is made with various 
Table i. Temperature and precipitation in the subalpine and alpine zones of Colorado 
compared with data from various points in the northern United States. 
Temperature in degrees Fahrenheit; precipitation in inches 
Station 
Subalpine zone (10,500 ft.) 
Alpine zone (Corona, 11,660 ft.) 
Denver, Colo. (5,275 ft.) 
St. Paul, Minn 
Duluth, Minn 
Chicago, 111 
New York, N. Y 
Mean Annual 
Temperature 
Mean July 
Temperature 
Mean Annual 
Precipitation 
34.01 
26.0 
49.8 
45-0 
39-0 
48.0 
52.0 
54.01 
47.0 
71.8 
74.0 
66.0 
72.0 
74.0 
32.01 
44.0 
14.0 
28.6 
29.9 
33-4 
44.8 
points in the northern United States- so that a clearer idea of the climate 
of our area of study may be gained. 
The temperature of the soil, as would be expected, is low. Numerous 
observations have been made at subalpine lakes. Readings at 3 dm. 
depth are shown in table 2. In analogous associations at ordinary altitudes 
in the northern United States the temperatures are 10 to 18 degrees higher. 
Table 2. Soil temperatures of subalpine lake shores for July; average of numerous 
observations at 3 dm. depth, in degrees F. 
Subalpine sedge moor, near water 50 
Subalpine meadow, on higher ground 52 
Subalpine spruce forest (dense) 48 
Subalpine forest openings (dry places) 60 
1 Data very meager; estimated by comparison with stations in the alpine and montane 
zones. 
