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Influence of landscape structure, topography, and forest type on spatial variation in historical fire regimes, Central Oregon, USA

Author(s): Andrew G. Merschel, Emily K. Heyerdahl, Thomas A. Spies, Rachel A. Loehman
Year Published: 2018

Context: In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes. Objectives: To identify the roles of topography, landscape structure, and forest type in driving spatial variation in historical fire regimes in mixed-conifer forests of central Oregon. Methods: We used tree rings to reconstruct multicentury fire and forest histories at 105 plots over 10,393 ha. We classified fire regimes into four types and assessed whether they varied with topography, the location of fuel-limited pumice basins that inhibit fire spread, and an updated classification of forest type. Results: We identified four fire-regime types and six forest types. Although surface fires were frequent and often extensive, severe fires were rare in all four types. Fire regimes varied with some aspects of topography (elevation), but not others (slope or aspect) and with the distribution of pumice basins. Fire regimes did not strictly co-vary with mixed-conifer forest types. Conclusions: Our work reveals the persistent influence of landscape structure on spatial variation in historical fire regimes and can help inform discussions about appropriate restoration of fire-excluded forests in the interior Northwest. Where the goal is to restore historical fire regimes at landscape scales, managers may want to consider the influence of topoedaphic and vegetation patch types that could affect fire spread and ignition frequency.

Citation: Merschel, Andrew G.; Heyerdahl, Emily K.; Spies, Thomas A.; Loehman, Rachel A. 2018. Influence of landscape structure, topography, and forest type on spatial variation in historical fire regimes, central Oregon, USA. Landscape Ecology 33(7):1195-1209.
Topic(s): Fire History, Fire Regime, Recovery after fire, Restoration
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 18317
FRAMES RCS number: 56182
Record updated: Nov 7, 2018