Levels-of-growing-stock cooperative study in Douglas-fir: report no. 13—The Francis Study, 1963-90.

Abstract

Results of the Francis installation of the levels-of-growing-stock study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), begun at stand age 15, are summarized together with results from additional first-thinning treatments started at age 25. To age 42 (5 years beyond the last planned thinning), total cubic-foot volume growth on this mid-site II Douglas-fir plantation has been strongly related to level of growing stock. Growth of lower levels of growing stock exceeded that of the control for only a brief period at age 30. Selection of a "best" treatment would depend on the unit of measure used: yield in total cubic-foot volume, merchantable cubic-foot volume, board-foot volume or dollar value. Close dollar values among several alternatives suggest that diverse stand structure objectives can be attained at age 42 with little difference in wood product-value per acre. General silvicultural prescriptions could be written to achieve the results of any of the treatments on similar sites.

Citation

Hoyer, Gerald E.; Andersen, Norman A.; Marshall, David. 1996. Levels-of-growing-stock cooperative study in Douglas-fir: report no. 13—The Francis Study, 1963-90. Res. Pap. PNW-RP-488. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 91 p