Silvicultural systems for maintenance of structure in a forest landscape

Recent direction of forest management on public land emphasizes creation and maintenance of wildlife habitat. Management guidelines range from providing specific structures at stand or smaller spatial scales to providing wide ranges of stand structure and age classes across large landscapes. Commonly, these guidelines arise in response the listing of a single wildlife species as sensitive, threatened, or endangered. The sense of urgency associated with such listings may lead to adoption of guidelines based on science that is the best available, but which has not necessarily been conducted for the purpose of developing management alternatives. Two such cases affecting forest management in the western United States are the northern goshawk, which is listed as la sensitive species by the U.S. Forest Service, and the Canada lynx, which is fisted as a threatened species by the U.S. Fish and Wildlife Service. In the latter case, attention been focused primarily on the snowshoe hare, which is the primary prey of the lynx. We address both of the above cases by developing stand structure models for goshawk nest sites and snowshoe hare habitat. We explore the application of silvicultural systems to landscape-scale stand dynamics through use of the Forest Vegetation Simulator and a custom analysis program.; Analysis of goshawk nest stands shows that these stands have undergone structural change due to recent mountain pine beetle infestations. We define a suitable habitat window based on stand diameter and density ranges found in stands prior to beetle infestation. Results from the snowshoe hare study indicate that a minimum stand density of approximately 2800 trees per hectare is required to produce adequate winter forage and cover. Retention of live crowns is an important factor in maintaining hare habitat quality. We describe silvicultural methods that can produce habitat characteristics defined in the hare and goshawk studies. Our landscape analysis indicates that it is possible to maintain a desired structural balance on the landscape with a limited set of restrictions. By analyzing the development of structure across an entire landscape, stand-level treatments can be directed to achieve and maintain landscape-level objectives over the long term.