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

Ecological Applications

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https://doi.org/10.1002/eap.1778

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Abstract

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.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Pre‐fire drought and competition mediate post‐fire conifer mortality in western U.S. National Parks
Series title:
Ecological Applications
DOI:
10.1002/eap.1778
Edition:
Online First
Year Published:
2018
Language:
English
Publisher:
Ecological Society of America
Contributing office(s):
Western Ecological Research Center