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Contemporary fires are less frequent but more severe in dry conifer forests of the southwestern United States

October 11, 2024

Wildfires in the southwestern United States are increasingly frequent and severe, but whether these trends exceed historical norms remains contested. Here we combine dendroecological records, satellite-derived burn severity, and field measured tree mortality to compare historical (1700-1880) and contemporary (1985-2020) fire regimes at tree-ring fire-scar sites in Arizona and New Mexico. We found that contemporary fire frequency, including recent, record fire years, is still <20% of historical levels. Since 1985, the fire return interval averages 58.8 years, compared to 11.4 years before 1880. Fire severity, however, has increased. At sites where trees historically survived many fires over centuries, 42% of recent fires resulted in high tree mortality. Suppressed wildfires tended to burn more severely than prescribed burns and wildfires managed for resource benefit. These findings suggest that expanded use of low-severity prescribed and managed fire would help restore forest resilience and historical fire regimes in dry conifer forests.

Publication Year 2024
Title Contemporary fires are less frequent but more severe in dry conifer forests of the southwestern United States
DOI 10.1038/s43247-024-01686-z
Authors E. McClure, J.D. Cooper, C. Guiterman, Ellis Margolis, S. Parks
Publication Type Article
Publication Subtype Journal Article
Series Title Nature Communications Earth & Environment
Index ID 70259564
Record Source USGS Publications Warehouse
USGS Organization Fort Collins Science Center
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