FOREST TYPES IN CENTRAL ROCKY MOUNTAINS. 9 



Monument Creek. Other buildings are not close enough to affect the 

 records in any way. The free sweep allowed the prevailing westerly 

 winds probably accounts for some of the phenomenal velocities re- 

 corded at this station. In addition, the southward sloping creek val- 

 ley tends to introduce an air drainage factor in the form of northerly 

 breezes, which are not at all felt on the mountain slopes, and the 

 north and northeast winds accompanying cyclonic storms arc also 

 not at all interfered with. Colorado Springs lies 4] miles from the 

 first abrupt rise of the mountains at Man it on, and 6 miles in an air 

 line from the Fremont Forest Experiment Station. 



The equipment of this station is that of a first-class weafher bureau 

 station, namely, maximum and minimum thermometers, thermo- 

 graph, anemometer, psychrometer, sunshine recorder, rain gages, and 

 triple register. No observations of ground or soil conditions are made. 

 The station has been maintained by the faculty and students of Colo- 

 rado College for about 35 years. The station is principally valuable 

 as forming a base for the whole Pikes Peak series, which extends from 

 this elevation to timberline at 11,500 feet. 



D-l : Black Hills western yellow pine. — Elevation, 4,535 feet. Valley 

 situation. Deadwood, S. Dak., is situated in the higher and moister 

 portion of the Black Hills but in a valley surrounded by relatively 

 high ground. It is therefore doubtful whether the station receives 

 greater precipitation than the average for the Black Hills region. 

 The record of precipitation and temperatures has been obtained for 

 a great many years, under a variety of conditions, and while the 

 conditions surrounding the taking of the late record used in this 

 study have not been investigated, it is believed that in distribution 

 of precipitation at least, which is the more important feature, the 

 record will be properly indicative. 



Due to artificial influences, the yellow pine forest immediately 

 surrounding this station is far from representative of the Black 

 Hills. However, this locality seems capable of producing the same 

 dense reproduction and the same excellent development of pure 

 yellow pine stands as any other portion of the hills, provided the soil 

 is favorable; but everywhere these qualities seem to be strongly 

 influenced by soils, and especially unfavorably by soils of limestone 

 origin. 



F-2: Fremont south slope western yellow pine. — Elevation, 8,921 feet; 

 aspect, S. 35° W.; slope, 34 per cent. This station is situated but 

 400 feet from the control station, and as it occupies the south ex- 

 posure of the same main valley it is subject to the same air currents. 



The forest is the typical western yellow pine stand of semiarid regions, 

 consisting of not over 20 or 30 trees per acre, with a maximum height 

 of 60 feet. Occasional specimens of limber pine are found, but 

 none of them attains a height equal to that of the yellow pine. The 

 station is quite strongly shaded on the east, but is more open to the 

 south and southwest. This fact, with the southwesterly aspect, 

 accounts for a very late maximum temperature each day, and in 

 part for the high soil temperatures recorded in the morning. (wSee 



kn,iig. i.) 



During the two-year period, March, 1910, to February, 1912, this 

 station was visited daily a few minutes later than the control sta- 

 tion. As at the control station, all observations except soil tem- 

 peratures, were made on a tower 20 feet above the ground. During 



