Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought

Nature Communications
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Abstract

Recently, Stovall et al.1 (hereafter SSY) showed that during an extreme drought, remotely sensed mortality of tall trees was more than double that of short trees. They interpreted this to be a consequence of inherently greater hydraulic vulnerability of tall trees, and suggested that tall-tree vulnerability should thus generalize more broadly. Here we reassess their conclusions using contemporaneous, ground-based data from near their study sites. We found that 90% of trees belonged to taxonomic groups showing declining, not increasing, mortality with height, and that the overall increase in mortality with height was instead a consequence of height-related changes in forest composition, not intrinsically greater vulnerability of tall trees. Similar mechanisms likely explain mortality patterns at SSY’s sites, and, regardless, we show that SSY’s conclusions should not be accepted in the absence of robust tests of alternative mechanisms.
Publication type Article
Publication Subtype Journal Article
Title Height-related changes in forest composition, not tree vulnerability, explain increasing mortality with height during an extreme drought
Series title Nature Communications
DOI 10.1038/s41467-020-17213-5
Volume 11
Year Published 2020
Language English
Publisher Springer Nature
Contributing office(s) Western Ecological Research Center
Description 3402, 4 p.
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