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



ASE 



Figure 36 — Quadratic mean diameter vs. age for grand fir precommercial thinning 

 to 250 trees per acre at 20 years and commercial thinning from below to 100 

 trees per acre at 50 years in Inland Northwest forests. 



33 



