[Chap. Llll THE VEGETATION OF NORTH AMERICA 775 



each of numerous subdivisions. Here we can sketch briefly only a few 

 characteristic forests. 



Pacific coastal forest (Figs. 401-409). The most magnificent forest in 

 temperate regions occupied the western slopes of the coastal moun- 



Fk:. 403. Interior \ lew ot mature lorest of western hemlock (Tsuga hetewphylla) 

 on a mountain slope in Washington. Photo hom U. S. Forest Service. 



tains between Vancouver and San Francisco. Rainfall up to 125 inches 

 occurs along the Oregon coast, with a gradual decrease northward 

 to Alaska and southward to San Francisco. Moreover, this is a belt 

 of fos^s and low clouds. Rainfall is least during summer. These 

 conditions rarely extend more than 30 miles inland except in north- 

 ern Oregon and Washington where there is a break in the coast 

 ranges. 



Beginning in Alaska the Sitka spruce is most abundant in the shore 



