CLIMATE AND PLANT GROWTH. 



39 



Oak-Brush Type 



Aspen - Fir 



Spruce —Fir 



Temperature 3bo\/e ^0°f 



P/iys/'o/oc//c9/ femperatune eff/c/ency 



Sumofc/a/Vy/ryean 



Pig. 19. — Temperature efficiency snmmations for period of growth of plants used in main 



experiment. 



