10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 



AGE 



Figure 43— Effect of thinning on standing volume of grand fir plantations (merchant- 

 able board feet [Scribner]), site index 70. 



120000 . 



liJ 



3 96000 ■ 



o 



> 



o 

 o 



_J 

 < 



° 48000 • 



24000 ■ 



10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 



AGE 



Figure 44 — Effect of thinning on standing volume of grand fir plantations (merchantable 

 board feet [Scribner]), site index 90. 



37 



