Historical fire and vegetation dynamics in dry forests of the interior Pacific Northwest, USA, and relationships to Northern Spotted Owl (Strix occidentalis caurina) habitat conservation.
Authors:
Kennedy, Rebecca S.H. Wimberly, Michael C. USDA, FS
Source:
Forest ecology and management. 2009 Aug. 20, v. 258, no. 5 [Amsterdam]: Elsevier Science, p. 554-566.
NALT Subjects:
Strix occidentalis wild birds fire regime fire severity wildlife habitats habitat conservation vegetation structure forest succession spatial data simulation models forest policy forest management planning endangered species Oregon Northwestern United States
Other Subjects:
Cascade Mountain region
Issue Date:
20-Aug-2009
Abstract:
Regional conservation planning frequently relies on general assumptions about historical disturbance regimes to inform decisions about landscape restoration, reserve allocations, and landscape management. Spatially explicit simulations of landscape dynamics provide quantitative estimates of landscape structure and allow for the testing of alternative scenarios. We used a landscape fire succession model to estimate the historical range of variability of vegetation and fire in a dry forest landscape (size ca. 7900km²) where the present-day risk of high severity fire threatens the persistence of older closed canopy forest which may serve as Northern Spotted Owl (Strix occidentalis caurina) habitat. Our results indicated that historically, older forest may have comprised the largest percentage of the landscape (~35%), followed by early successional forest (~25%), with about 9% of the landscape in a closed canopy older forest condition. The amount and condition of older forest varied by potential vegetation type and land use allocation type. Vegetation successional stages had fine-grained spatial heterogeneity in patch characteristics, with older forest tending to have the largest patch sizes among the successional stages. Increasing fire severities posed a greater risk to Northern Spotted Owl habitat than increasing fire sizes or frequencies under historical fire regimes. Improved understanding of historical landscape-specific fire and vegetation conditions and their variability can assist forest managers to promote landscape resilience and increases of older forest, in dry forests with restricted amounts of habitat for sensitive species.
