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Towards improved quantification and prediction of post-fire recovery in conifers: Expanding laboratory fire radiative energy-tree physiology experiments to a mature forest stand - JFSP Final Report

Author(s): Crystal A. Kolden, Aaron M. Sparks
Year Published: 2018
Description:

Current assessments of the ecological impacts of fires, termed burn severity, investigate the degree to which an ecosystem has changed due to a fire and typically encompass both vegetation and soil effects. Burn severity assessments at local to regional scales are typically achieved using spectral indices (such as the differenced normalized burn ratio and the Relativized differenced Normalized Burn Ratio) derived from satellite remote sensing data before and following the fires. Although considerable efforts have been made to quantify post-fire burn severity across large spatial extents through spectral data, the explicit physiological link between fire behavior, tree mortality, and spectral reflectance is lacking, and inhibits prediction and quantification of tree mortality and recovery post-fire. Recent studies have highlighted the potential of linking fire behavior to plant ecophysiology as an improved route to characterizing severity, but research to date has been limited to laboratory-scale investigations. In this study, fire behavior was quantified at the tree-and landscape-scale and compared with post-fire growth, defenses, and productivity. Results show a clear dose-response relationship between peak fire radiative flux density (FRFD: W m-2) and post-fire ponderosa pine (Pinus ponderosa) radial growth. Increasing levels of peak fire radiative power resulted in reduced post-fire radial growth. Permanent defense structures (axial resin ducts) were found to increase in density, size, and area per growth ring post-fire regardless of fire intensity. Satellite-based remote sensing observations of coniferous forests in the northwest United States were used to test the dose-response hypothesis at the landscape spatial scale. Similar to observations at the tree scale, satellite measures of forest productivity decreased with increasing fire radiative power. Species composition was demonstrated to influence the magnitude of productivity loss post-fire. Ultimately, this work provides critical first steps in building a framework to spatially characterize individual tree and forest condition post-fire, improving our understanding of the carbon cycle and ability to sustainably manage forests.

Citation: Kolden, Crystal A.; Sparks, Aaron M. 2018. Towards improved quantification and prediction of post-fire recovery in conifers: expanding laboratory fire radiative energy-tree physiology experiments to a mature forest stand - Final Report to the Joint Fire Science Program. JFSP Project No. 16-2-01-9. Moscow, ID: University of Idaho. 18 p.
Topic(s): Fire Regime, Fire Intensity / Burn Severity, Mapping, Post-fire planning / management
Ecosystem(s): None
Document Type: Technical Report or White Paper
NRFSN number: 17721
FRAMES RCS number: 55913
Record updated: Jun 5, 2018