FOR WHOLE TREES. 



75 



500 



400 



300 



U. 



200 



1OO 



' mma 



18 



22 



26 3O 34 38 



DIAMETER BREASTH1GH INCHES 



42 



46 



FIG. 80. -Curves showing average age in years of immature and mature western 

 yellow pine trees of different diameters breasthigh. 



