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Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks

Author(s): Phillip J. van Mantgem, Donald A. Falk, Emma C. Williams, Adrian J. Das, Nathan L. Stephenson
Year Published: 2018
Description:

Tree mortality is an important outcome of many forest fires. Extensive tree injuries from fire may lead directly to mortality, but environmental and biological stressors may also contribute to tree death. However, there is little evidence showing how the combined effects of two common stressors, drought and competition, influence post‐fire mortality. Geographically broad observations of three common western coniferous trees subjected to prescribed fire showed the likelihood of post‐fire mortality was related to intermediate‐term (10 yr) pre‐fire average radial growth, an important component of tree vigor. Path analysis showed that indices of competition and drought stress prior to fire can be described in terms of joint effects on growth, indirectly affecting post‐fire mortality. Our results suggest that the conditions that govern the relationship between growth and mortality in unburned stands may also apply to post‐fire environments. Thus, biotic and abiotic changes that affect growth negatively (e.g., drought stress) or positively (e.g., growth releases following thinning treatments) prior to fire may influence expressed fire severity, independent of fire intensity (e.g., heat flux, residence time). These relationships suggest that tree mortality may increase under stressful climatic or stand conditions even if fire behavior remains constant.

Citation: van Mantgem PJ, Falk DA, Williams EC, Das AJ, Stephenson NL. 2018. Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks. Ecological Applications 28 (7): 1730-1739. https://doi.org/10.1002/eap.1778
Topic(s): Fire Behavior, Fire Prediction, Post-fire Management
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 18275
Record updated: Nov 6, 2018