Effects of new forest management strategies on squirrel populations

Two strategies for managing forests fur multiple values have achieved prominence in debates in the Pacific Northwest: (1) legacy retention with passive management and long rotations, and (2) intensive management for timber with commercial thinnings and long rotations. Northern flying squirrels (Glaucomys sabrinus), Townsend's chipmunks (Tamias townsendii), and Douglas' squirrels (Tamiasciurus douglasii) were studied retrospectively in Douglas-fir (Pseudotsuga menziesii) forests managed under the alternative strategies in the Puget Trough of Washington. Flying squirrels were twice as abundant under legacy retention as under intensive management fur timber, almost as abundant as in old-growth western hemlock (Tsuga heterophylla) forests on the Olympic Peninsula of Washington, but <50% as abundant as in old-growth Douglas-fir forests in western Oregon. Chipmunks were four times as abundant under intensive timber management. as under legacy retention, but less abundant than in old-growth forests. Abundance of Douglas' squirrels did not differ between strategies. Neither strategy produced the increased abundance of all three species that is an emergent property of late-seral forests. A third strategy holds promise: active, intentional ecosystem management that incorporates legacy retention, variable-density thinning, and management for decadence.