MGMT 



000 

 POO 



PCB 

 PCA 

 PCI 



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



AGE 



Figure 27 — Effect of thinning on total yield of Douglas-fir plantations 

 (merchantable board feet [Scribner]), site index 70. 



MGMT 



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



AGE 



Figure 28— Effect of thinning on total yield of Douglas-fir plantations (merchantable 

 board feet [Scribner]), site index 90. 



24 



