146 



UNIVERSITY OF COLORADO STUDIES 



are somewhat more branched than elsewhere but seem not to be dwarfed. 

 All of the species of Salix and the single Betula are present on the windy 

 east shore quite as much as in the protected parts at the west end of the 

 lake. The single species of Lonicera does not occur along the windy 

 shore. Among trees the limber pine is more abundant in windy places 

 but as these situations are more dry it may be that the distribution of 

 this pine is not related to wind but to soil dryness and that it grows 

 only in the areas not otherwise occupied. In these dry places the 

 limber pine has an opportunity to grow because there is no competition 

 of Engelmann spruces. These latter trees regularly frequent the 

 moister soil. In view of what has been said it is safe to conclude that 

 wind is of a very secondary importance to the vegetation except in its 

 effect upon the development of "wind timber." 



Comparisons with Climate of Other Stations. — The climate of Red- 

 rock Lake is distinctly cool. During the summer months the tempera- 

 ture is 25 degrees lower than at St. Louis, 10 degrees lower than at 



Table II. Summer Temperatures at Redrock Lake and at Certain Far 

 Northern Stations {Degrees F.) 



Station 



Aug. 



Ft. Conger,* Grinnell Land, 8i° 44' N., 64 45'W. Alt. 



sea level 



Ft. Churchill, f Hudson Bay, N.W.T., 58 51' N., 94 n' W. 

 Redrock Lake, Colo., 40 05' N., 105 30' W., Alt. 10,100 ft. 



above sea level 



Banff, Alberta,f 51 10' N., 115° 34' W. Alt. 4,542 ft. above 



sea level 



Dawson, Yukon, f 64 4' N., 139 20' W., Alt. 1,200 ft. 



above sea level 



33-4 

 51.0 



5i-4 

 56.8 



55-3 



* Schimper, Plant Geography (English Translation), p. 667. 1903. 



t Report 0} the Meteorological Sennce of Canada (1905), published 1907. [Banff is the highest-altitude 

 station in the Rocky Mountains of Canada where records are made.] 



Duluth, Minn., and even 8 degrees lower than Dawson, Yukon (cf. Fig. 6 

 and Table II) . The summer climate is by no means arctic as is shown 

 by Table II, in which a number of comparisons are made. Winter 

 temperatures are probably not very low, perhaps such as would occur 

 at Chicago, 111., or Albany, N. Y. It is certain that the winters are far 

 warmer than at St. Paul or at Duluth, Minn. In precipitation, with 

 about 760 mm. (30 inches) per annum, Redrock Lake has a lower annual 



