135 - 



1 I I I I 



50 100 150 200 250 



Weight of roots (g/m-) 



Figure 2. — Vertical distribution of total root mass. The short vertical lines are 

 interpolated values for layers not sampled in 1965-1966 . The curve is an approx- 

 imation of minimum root mass distribution at depths greater than 22.5 cm. ^ not 

 sampled in 1970. 



11 



