212 WILLIAM S. COOPER 



west face of Mt. Robson, from its summit (13,068 feet, 4021 

 meters) to Lake Kinney (3250 feet, 1000 meters) is a single 

 slope of 9800 feet (3015 meters), with an average inclination of 

 45°. The effects of present and past glaciation and of post- 

 glacial weathering are of course apparent everywhere, and 

 these are the controlling physiographic factors in reference to 

 vegetation. 



Climate. 1 know of no climatic records pertaining to this 

 vicinity. It may be safely stated that precipitation is heavy 

 and well distributed through the year. Cloudy weather with 

 frequent showers is the rule in summer in the vicinity of Mt. 

 Robson, but thunderstorms are rare. Upon Robson Pass sum- 

 mer temperatures are low, and frosts occur in midsummer, 

 while upon the higher mountains snow falls in considerable 

 quantities at frequent intervals. In the lower valleys the 

 temperatures are considerably higher. At the main Fraser 

 River (3000 feet, 923 meters) a temperature of 84°F. (30°C.) 

 in the shade was noted July 4. 



Vegetation zones. The vegetational and presumably climatic 

 zones are three. The lowest extends in this vicinity up the 

 Fraser and its Grand Fork to the cliffs at the head of Lake 

 Kinney (3250 feet, 100 meters). The forest in this, which may 

 be termed the Montane Zone, is of the type found upon the 

 British Columbia Coast Ranges and in the lower zone of the 

 Selkirks. In the region from 3500 feet (1077 meters) to timber- 

 line at 6500 feet (2000 meters) — the Subalpine Zone — the 

 forest differs partially from the lower in species, and is very 

 different in size of trees. Above timberline lies the Alpine Zone, 

 characterized by Alpine meadows and rock and snow wastes. 

 The present study deals with the two forest zones. 



A. PHYSIOGRAPHY 



Before discussing the vegetation it will be well to outline the 

 physiographic processes which have been and are in operation 

 in the region, since it is through the operation of such processes 

 that new surfaces are laid bare for the initiation of primary 



