USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Tree Mortality

Managing Forests and Wildlife: Spotted Owls and Fishers

Forests provide habitat for a wide variety of wildlife species. Researchers explain how variable forest conditions can help support species like the California spotted owl and fishers.

Through forest management, habitat can be improved for some of the species that are most threatened. Work being done in experimental forests is helping to advance our understanding of the effects of a variety of restoration treatments to forest structure and wildlife.

Research published in 2017 shows that management strategies designed to preserve and facilitate the growth of tall trees while reducing the cover and density of understory trees may improve forest resilience to drought and wildfire while also maintaining or promoting the characteristics of spotted owl habitat.

Current research: Use of snag islands by black-backed woodpeckers following post-fire tree removal

The black-backed woodpecker (Picoides arcticus) is a snag-associated species that lives in and uses patches of burned forests typically within 10 years of fire. Previous research has indicated that salvage logging, the removal of dead and dying trees, from burned forests has a negative effect on nesting densities of black-backed woodpeckers.

One strategy proposed to help improve the impacts of dead tree removals on black-backed woodpeckers is to retain patches, or islands, of dense snag areas within the salvage area, but this approach had not been tested. Following the Angora Fire in South Lake Tahoe, California, several snag islands were retained for black-backed woodpeckers and other snag-associated species. Researchers systematically searched the post-fire landscape for black-backed woodpecker nests for two years before and after salvage operations and compared nesting densities between stands that were logged, patches of snags (snag islands), and other unlogged areas at the fire-, stand- and nest-scale.

Researchers found that nest densities of black-backed woodpeckers at the stand scale declined significantly in areas that were salvage logged, but black-backed woodpeckers did nest in snag islands within the salvage area and in other unlogged areas, indicating that leaving dense stands of dead trees within the fire footprint may help balance habitat for wildlife with management needs at the scale of the fire.

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