Regional patterns in U.S. wildfire activity: The critical role of ignition sources

Environmental Research Letters
By: , and 

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Abstract

As extreme wildfires increase globally, understanding their causes is critical for effective management. While climate and housing growth are commonly linked to rising fire activity, the role of specific ignition sources—particularly human-caused—remains understudied. Analyzing a 79-year dataset (1940–2019) from U.S. Forest Service regions across the continental United States, we found that different ignition sources in different regions have been a major driver of wildfire trends, accounting for 60%–80% of the interannual variation in fire frequency and approximately 20% in area burned across most U.S. regions. Lightning and campfires were the dominant sources in western regions, while arson drove fire activity east of the Mississippi River. Trends also varied significantly by region and over time, with housing growth explaining more in terms of fire frequency and climate primarily influencing area burned. Importantly, frequent fires often originated from different sources than those causing the largest areas burned. Prevention of human-caused ignitions, such as campfires and arson, could offer efficient and effective strategies to mitigate wildfire impacts on human and natural systems under changing climate and land-use conditions.

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Publication type Article
Publication Subtype Journal Article
Title Regional patterns in U.S. wildfire activity: The critical role of ignition sources
Series title Environmental Research Letters
DOI 10.1088/1748-9326/adc9c8
Volume 20
Publication Date April 22, 2025
Year Published 2025
Language English
Publisher IOP Science
Contributing office(s) Western Ecological Research Center
Description 054046, 11 p.
Country United States
Other Geospatial contiguous United States
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