1130 
Journal of Agricultural Research 
Vol. XXXI, No. 12 
0 -«--:------ 
0 20 -40 60 80 100 120 140 160 
TOTAL AGEL.YCARS 
Fig. 5 —Diameter of average tree on age 
determination; that is, both are primarily adapted to use in second- 
growth stands, and depend on measurement of plots for determination 
of either basal area per acre or volume per acre. In neither case is 
there any way of applying the results to areas of virgin forest, which 
seems to be the most important problem we have just now. 
