Economic Evaluation of Thinning Alternatives in a Western Hemlock-Sitka Spruce Forest
Abstract As part of a multidisciplinary study on managing young western hemlock (Tsuga heterophylla)-Sitka spruce (Picea sitchensis) stands in the Pacific Northwest, a present net worth analysis of thinning impacts on financial returns at final harvest was completed. Two 32-year-old precommercially thinned stands were selectively and strip thinned with a skyline logging system, and stand growth was projected to rotation age 70 years with a stand-table projection model. A harvest simulation model was then used to estimate harvest costs and revenues from clearcutting at rotation age. Regardless of model assumptions, present net worth was highest for the control (no thinning). A sensitivity analysis of variations from base-case assumptions did not alter the outcome. Study results suggest that if density of managed western hemlock-Sitka spruce stands has been sufficiently controlled with precommercial thinning, they will develop adequately to a rotation-age harvest without intermediate thinning. West. J. Appl. For. 3(1):14-17, January 1988.