486 



PLANT GEOGRAPHY 



Trees at great elevations are stunted and gnarled by scanty 

 nutrition and pressure of wind and snow (Fig. 370). 



' 



> x>; 

 X'^UiA^'- ! 



lll^ ? ' 



EIG. 371. Decrease in size of trees at high elevations (Canadian Rockies) 



Where the prevailing winds come mainly from one quarter, 

 all the trees of considerable areas may be inclined strongly in 

 one direction, as in Plate XL 1 



1 This phenomenon is also very noticeable along many coasts. 



