Guidelines for Precommercial Thinning of Douglas-Fir

Portland

1975

10 S.

Bandaufführung

9202

87567

Production of merchantable wood in even-aged Douglas-fir stands can be increased substantially by precommercial thinning. Guidelines for, and gains from, precommercial thinning both strongly depend on the size of trees wanted at the first commercial cut; the larger this size, (1) the fewer trees should be left after precommercial thinning, (2) the greater is the maximum age or tree size at which precommercial thinning is practical, and (3) the greater is the gain in usable yield from precommercial thinning. Also, generally, the longer the time required for a stand to reach commercial size without thinning, the greater the gains from precommercial thinning. These and other considertations are discussed, and procedures are recommended.