10000 



8000 



6000 



4000 ■ 



2000 



MGMT 



000 

 POO 



PCB 

 RCA 

 PCI 



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



AGE 



Figure 23 — Effect of thinning on total yield of Douglas-fir plantations (total cubic 

 feet), site index 50. 



j4000 



12000 



000 

 POO 

 PCA 

 PCB 

 PCI 



2000 - 



Figure 24 — Effect of thinning on total yield of Douglas-fir plantations (total cubic 

 feet), site index 70. 



22 



