Fire intensity impacts on physiological performance and mortality in Pinus monticola and Pseudotsuga menziesii saplings: a dose–response analysis

作者：Aaron M. Sparks, Alexander S. Blanco, David R. Wilson, Dylan W. Schwilk, Daniel M. Johnson, Henry D. Adams, David M. J. S. Bowman, Douglas D. Hardman, Alistair M. S. Smith · 发表于：Tree Physiology · 年份：2023 · DOI：10.1093/treephys/tpad051 · 被引用次数：16 · 研究领域：Fire effects on ecosystems、Plant Water Relations and Carbon Dynamics、Forest ecology and management

Fire is a major cause of tree injury and mortality worldwide, yet our current understanding of fire effects is largely based on ocular estimates of stem charring and foliage discoloration, which are error prone and provide little information on underlying tree function. Accurate quantification of physiological performance is a research and forest management need, given that declining performance could help identify mechanisms of-and serve as an early warning sign for-mortality. Many previous efforts have been hampered by the inability to quantify the heat flux that a tree experiences during a fire, given its highly variable nature in space and time. In this study, we used a dose-response approach to elucidate fire impacts by subjecting Pinus monticola var. minima Lemmon and Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco saplings to surface fires of varying intensity doses and measuring short-term post-fire physiological performance in photosynthetic rate and chlorophyll fluorescence. We also evaluated the ability of spectral reflectance indices to quantify change in physiological performance at the individual tree crown and stand scales. Although physiological performance in both P. monticola and P. menziesii declined with increasing fire intensity, P. monticola maintained a greater photosynthetic rate and higher chlorophyll fluorescence at higher doses, for longer after the fire. Pinus monticola also had complete survival at lower fire intensity doses, whe...