The effects of prolonged drought on vegetation dieback and megafires in southern California chaparral

Ecosphere
By: , and 

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Abstract

Drought contributed to extensive dieback of southern California chaparral, and normalized difference vegetation index before drought and near the end of the drought was used to estimate this dieback, after accounting for other disturbances recorded in aerial photographs. Within the perimeters of two megafires that occurred after the drought, the 2017 Thomas Fire and the 2018 Woolsey Fire, there had been extensive areas of dieback. Comparing dieback with Monitoring Trends in Burn Severity measures of fire severity, there was a highly significant negative relationship between drought-caused shrub dieback and fire-caused dieback as measured by fire severity. We interpret this as further support for our remote sensing methodology for prefire dieback. Models of fire behavior suggest that one means by which dieback contributes to fire size is through increasing the density and distance of spot fires, particularly under extreme wind conditions. Lower elevation chaparral associations appear to be most vulnerable and are closer to urban environments, which should be a concern to fire managers in regions subjected to extended droughts.

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Publication type Article
Publication Subtype Journal Article
Title The effects of prolonged drought on vegetation dieback and megafires in southern California chaparral
Series title Ecosphere
DOI 10.1002/ecs2.4203
Volume 13
Issue 8
Year Published 2022
Language English
Publisher Ecological Society of America
Contributing office(s) Western Ecological Research Center
Description e4203, 16 p.
Country United States
State California
County Los Angeles County, Santa Barbara County, Venture County
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