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 Fire Science

Restoring fire-resilient landscapes

Historically, forests that evolved under active, frequent fire appeared as a patchwork across the landscape with low density stands of large trees on south-facing slopes and ridge tops, openings of rock and shrubs, and pockets of dense, multilayered forest largely in drainage bottoms and on north-facing slopes. Management practices over the last 100 years have resulted in forests that are much more homogenous, or similar across the landscape, with many more trees and higher canopy cover and increased fuel loading than existed with active, frequent fire. Unless treated, these conditions will limit forest resilience to fire as well as drought, climate change effects, and other disturbances.

Increasing forest resilience in the Sierra Nevada, Southern Cascades, Klamath-Siskiyou ecosystems and many other conifer forest landscapes in the West will require management strategies that work with and adapt to dynamic ecological processes at larger scales. Research suggests that management practices that mimic the structure and composition that might have been produced by historical, frequent fire disturbance can increase forest landscape heterogeneity (diversity) at multiple scales.

Some Sierra Nevada forest managers have begun using topography as a surrogate of site productivity, moisture availability, and relative vulnerability to fire to determine suitable treatments. They work with existing stand conditions and use topography as a template to vary treatments while meeting objectives for reducing fire hazards, maintaining wildlife habitat, and restoring forests. This approach is consistent with recent research showing that topography, site productivity, and fire history interact to influence burn intensity and forest heterogeneity.

Management activities that reduce density of trees and move forests toward the range of conditions that would result from natural interactions between frequent fire and varying site productivity are likely to improve landscape resilience to both acute (e.g., high-severity wildfire, drought, etc.) and chronic disturbances (e.g., understory burning, climate change, bark beetles, air pollution, etc.).

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