12 BULLETIN 12.33, U. S. DEPARTMENT OF AGRICULTURE. 



F.S: Fremont west slope limber pine. — Elevation, 9,060 feet; 



aspect, X. 4S° W.; slope, 3*2 per cent. Situated near the top of a 

 steep northwest slope, -with a wide canyon to the west, this stal 



the full sweep of the desiccating winter winds from the west. 

 At this point the slope is less steep than below, and the type is less 

 completely one of limber pine, for it contains some yellow pines, 

 which form the main stand on the ridge just to the east. However, 

 at -the station the limber pine strongly -predominates. Like all 

 exposed westerly slopes in the Pikes Peak region, this one shows the 

 effect of the winter blasts. The ground is swept bare, and practi- 

 cally no ground cover appears even for short periods in the summer. 

 (See PL II. fig. 2). In spite of its apparent poverty, however, the 

 soil at the station was found to contain an unusual amount of fine 

 mineral material and humus. Pure stands of limber pine are ex- 

 tremely rare in the central Rockies, and for this reason the study of 

 the conditions which might have brought this one into being was 

 begun with great interest. 



The equipment of Station has all been placed at the ground, as 

 follows 



1 and 4 foot soil thermometers, July 0. 1914. to December 12, 1914; March 3, 

 1915, to February 29, 1916; and .May 11. 1917. to September, 1920. Iron pipe 

 at 1 foot replaced by wooden tube April 26, 191S. 



Ground and soil-.surface temperatures, May to Septem' 



Soil well, with moisture determinations for 1, 2, and 3 rtablished July, 



1914, and operated during open seasons of 1914, 1915, and 1917. 



Maximum and minimum thermometers, in shelter, March 15. 1915, to Febru- 

 ary 29, 1910. 



Anemometer (elevation, 18 inches), March 5, 1915, to February 29, 1910. 



Evaporimeter, inner-cell, Tvpe 4, Februarv to September, 1918; May, 1919. to 

 September, 1920. 



F—t : Fr< moid north slope spruce-Jirj char-cut. — Elevation. 9,105 fret: 



aspect. N. 16° E.; slope 34 per cent. This station is situated near 



the middle of a north slope whose total width is about 4(H) feet. It 



60 feet higher than the stream channel directly below, where 



Station 5 is situated. 



Station 7 is in the lower third of an opening about 250 fee' a 

 which was made by clear-cutting the forest. At this level the 

 original stan dense mixture of Engelmann spruce and 1 Douglas 



fir in air Lai proportions, with occasional specimens of limber 



pine and yellow pine and a few subordinate and decadent aspens. 

 The area was cut over in the fall of 1913, ami up to the present 

 there is practically no cover except aspen sprouts. 3 to 5 feet high, 

 and herbs. 



This station, together with Stations S. 1). 14, am! L5, represents 



the conditions on four near-by identical acre plots from which the 



timber has been cut in different wa B cause of a break in the 



slope just above the middle of plot 1. two stations, 7 and v were 



thougnt necessary to represent its soil conditions; but a single 



ion at tiie center, known as 7 8, was considered adequate for 



atmospheric measurements. Thus together. Stations 7. 7 8 and 8 



an- the <-<"" : Station 9 in the uncut plot (2) to the east, 



md I.") at the centers of the two additional plots 



i which only a portion of the timber was removed. TTiese will 



be described later, it i^ important to remember that these four 



station- (or six, considered mdividually) represent essentially the 



