10 BULLETIN 1233, U. S. DEPARTMENT OF AGRICULTURE. 



later years some additional records of ground temperatures and 

 evaporation have been secured for short periods. This station, with 

 the following one, furnished the main part of the data presented in 

 the preliminary report (3) on this study. 

 The full equipment is as follows: 



Tower (F-2A): 



Maximum and minimum thermometers, in standard shelter, March 1, 1910, 

 to February 28, 1912. 



Air thermograph, February 1, 1911, to February 28, 1912. 



Anemometer, March 1, 1910, to February 29, 1912. 



Psychrometer, March 1, 1910, to February 29, 1912. 



8-inch rain" gage, March 1, 1910, to February 29, 1912. 

 Ground (F-2G) : 



1-foot soil thermometer, in iron pipe, February 10, 1910, to February 29, 1912. 



2-foot soil thermometer, in iron pipe, February 10, 1910, to February 29, 1912. 



(In addition, these points were observed in spring and fall of 1913, and in 

 1914 from May to July, when the 4-foot depth was substituted for the 2-foot 

 depth.) 



1 and 4 foot soil thermometers, in iron pipes, July 9 to December 12, 1914; 

 March 1, 1915, to February 29, 1916; and May 11^ 1917, to September, 1918. 

 On April 26, 1918, a wooden tube was substituted for the iron pipe at the 1-foot 

 depth. 



Soil samples at random during growing season July, 1910, to October, 1911. 



Soil well in operation during growing seasons after June 29, 1914, and exclud- 

 ing 1916. Regular determinations at 1, 2, and 3 feet, and in 1917 at surface. 



Piche evaporimeters, as modified bv Weather Bureau, Mav 5, 1914, to Feb- 

 ruary 29, 1916. 



Evaporimeter, inner-cell, Type 4, February to September, 1918; May, 1919, 

 to April, 1920. 



Maximum and minimum thermometers, on shielded board, March 2, 1915, to 

 February 29, 1916. 



F-3: Fremont Canyon spruce. — Elevation, 8,860 feet; aspect, N. 

 44° E.; slope, 54 per cent. This station, like the preceding, is only 

 about 400 feet from the control station. It is situated at the foot 

 of a steep northeasterly slope, only a few feet above one of the small 

 streams. (See PI. I, fig. 2.) It is cut off from the air currents which 

 principally affect Stations 1 and 2 by the westward extension of the 

 ridge on which Station 1 is located, and which becomes considerably 

 higher opposite Station 3. The ground at Station 3 is so close to 

 the stream as to feel very markedly the cold-air stream at night, 

 which on the 20-foot tower is much less apparent. 



This type is strictly Engelmann spruce at the station, although 

 as one ascends the slope to a more exposed situation the forest quietly 

 changes to one of Douglas fir. For this reason, in an earlier report 

 (3), this station was described as representing a spruce-fir type. The 

 predominance of spruce at the very foot of northerly slopes at this 

 elevation is typical, and the purely local condition should here be 

 considered. The stand has come in since a lire which occurred about 

 00 years ago. 



This station has had the same equipment and has been under 

 observation during the same periods as F-2, with a few insignificant 

 exceptions. 



F-/ h ' Fremont east slope pine-fir. — Elevation, 9,1 17 feet; aspect, N. 

 88° E.; slope, 27 per cent. This station is placed on a moderate cast 

 slope, where it receives the lull effect of the morning sun, which, 

 especially during the warmer months, is usually unobscured. The 

 station lies between two very shallow depressions, not over 20 feet 



