Biology and management of the western gray squirrel and Oregon white oak woodlands: with emphasis on the Puget Trough.

Abstract

The western gray squirrel (Sciurus griseus Ord, 1818) has been accorded "threatened species" status by the state of Washington. populations are small, scattered, and declining primarily due to the loss and fragmentation of suitable habitat. Western gray squirrels are closely associated with Oregon white oak (Quercus garryana Dougl. ex Hook.) conifer communities on forest-prairie-wetland interfaces. Several other wildlife species also are closely tied to Oregon white oak woodlands. Oak woodland wildlife habitat is being reduced and fragmented by human development. Management of oak woodlands is necessary to protect ecological biodiversity, wildlife habitat, and habitat quality of existing oak woodlands. Specific management goals include maintaining large, open-form oak stands with adjacent intergrading conifers, prairies, and wetlands; preventing habitat fragmentation; maintaining open to patchy understory devoid of invasive species such as Scot's broom; and minimizing human disturbances that could accelerate root damage to oaks. Management recommendations include removing overtopping Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco) except old-growth trees; thinning dense understory oak and Douglas-fir to release remaining oaks; maintaining or developing habitat corridors to link scattered oak patches; using prescribed burning to prevent dense shrub competition; and promoting oak woodland conservation and enhancement on public and private lands through information, education, and legislation.

Citation

Ryan, L.A.; Carey, A.B. 1995. Biology and management of the western gray squirrel and Oregon white oak woodlands: with emphasis on the Puget Trough. Gen. Tech. Rep. PNW-GTR-348. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 36 p