FOREST TYPES IN CENTRAL ROCKY MOFN TAINS. 15 



is a decomposed gneiss which forms a grayish, gravelly sand not 

 wholly devoid of clay. On account of the heavy snows which lie 

 until summer, and the presence of the water table at a depth of 6 to 

 8 feet, the soil is usually saturated during the early part of the growing 

 season, but gradually dries out to a low point. This seems to be 

 true of a considerable area about Foxpark, though the moisture is 

 perhaps greater at the station than in the forest as a whole. 



This station is the only one in the lodgepole pine type for which 

 soil data are recorded. It is located very close to Foxpark post office, 

 almost on the line between Colorado and Wyoming, in longitude 106° 

 W. The entire plateau about Foxpark bears an almost unbroken 

 forest of lodgepole of very good quality, but a few high points pro- 

 jecting out of the plateau bear mixed stands of spruce and lodgepole. 

 About 5 miles to the east of Foxpark the plateau breaks off abruptly 

 to the plains, and on these slopes are found a few specimens of yellow 

 pine and Douglas fir. 



The Weather Bureau installed maximum and minimum ther- 

 mometers and an 8-inch rain gage at this station in March, 1911, and 

 the earlier record of temperatures as used in this report is taken 

 directly from Weather Bureau summaries. In March, 1916, the 

 Forest Service supplemented this equipment with the following, 

 which was in use through August, 1918: 



Psychrometer. 



Anemometer. 



Evaporimeter, inner-cell, Type 2. This was replaced by Type 4 evaporimeter, 

 January 15, 1917. 



Still earlier, in August, 1914, soil thermometers had been installed, in iron 

 pipes, at depths of 1 and 2 feet, the latter being lowered to 4 feet on March 15, 

 1916. 



A soil well was prepared in July, 1916, and weekly soil samples at the surface 

 and at depths of 1, 2, and 3 feet have been taken during the open season since 

 August 1, 1916. 



It is to be noted here that the observations for the Foxpark station 

 have been more or less irregular, owing to the frequent absence of 

 the observer for several days at a time. However, the air temper- 

 atures, which would be most affected, have now been observed for 

 a sufficient number of years so that the uncompensated error should 

 be quite small. 



F-12: Fremont Ridge ivestern yellow pine. — Elevation, 9,164 feet; 

 aspect, S. 20° E.; slope, 8 per cent. This point is on a broad, well- 

 rounded ridge that has a general east-west bearing, but very little slope 

 for a considerable distance east or west of the station. (See PL V, 

 fig. 1.) It is thus very evenly exposed on all sides, and at the outset 

 the exposure to wind from all directions was thought to account largely 

 for the very scrubby growth of the yellow pine. 



The stand immediately surrounding the station is, for the most 

 part, young, having probably originated after a fire about 60 years 

 ago. The trees range from a height of about 20 feet down to tiny 

 seedlings. Yellow pine strongly predominates in numbers, but 

 Douglas fir and limber pine are also coming in, and these two species 

 likewise occur in all sizes. The yellow pine was very badly infected 

 with mistletoe, which was seriously retarding the growth of most 

 trees and gradually claiming victims. The elimination of diseased 

 trees during the winter of 1917-18 has markedly improved appear- 

 ances and the general rate of growth. No cutting was done close to 



