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Tree crown injury from wildland fires: causes, measurement, and ecological and physiological consequences

Author(s): J. Morgan Varner, Sharon M. Hood, Doug P. Aubrey, Kara M. Yedinak, J. Kevin Hiers, William Matt Jolly, Timothy M. Shearman, Jennifer K. McDaniel, Joseph J. O'Brien, Eric Rowell
Year Published: 2021

The dead foliage of scorched crowns is one of the most conspicuous signatures of wildland fires. Globally, crown scorch from fires in savannas, woodlands, and forests causes tree stress and death across diverse taxa. The term crown scorch, however, is inconsistently and ambiguously defined in the literature, causing confusion and conflicting interpretation of results. Furthermore, the underlying mechanisms causing foliage death from fire are poorly understood. The consequences of crown scorch—alterations in physiological, biogeochemical, and ecological processes and ecosystem recovery pathways— remain largely unexamined. Most research on the topic assumes the mechanism of leaf and bud death is exposure to lethal air temperatures, with few direct measurements of lethal heating thresholds. Notable information gaps include how energy transfer injures and kills leaves and buds, how nutrients, carbohydrates, and hormones respond, and what physiological consequences lead to mortality. We clarify definitions to encourage use of unified terminology for foliage and bud necrosis resulting from fire. We review the current understanding of the physical mechanisms driving foliar injury, discuss the physiological responses, and explore novel ecological consequences of crown injury from fire. From these elements, we propose research needs for the increasingly interdisciplinary study of fire effects.

Citation: Varner, J. Morgan; Hood, Sharon M.; Aubrey, Doug P.; Yedinak, Kara; Hiers, J. Kevin; Jolly, W. Matthew; Shearman, Timothy M.; McDaniel, Jennifer K.; O’Brien, Joseph J.; Rowell, Eric M. 2021. Tree crown injury from wildlhttps://nph.onlinelibrary.wiley.com/doi/10.1111/nph.17539and fires: causes, measurement, and ecological and physiological consequences. New Phytologist 231(5):1676-1685. https://doi.org/10.1111/nph.17539
Topic(s): Fire Ecology, Fire Effects
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 23691
FRAMES RCS number: 63825
Record updated: Oct 19, 2021