Class Year

2025

Document Type

Student Research Paper

Date of Creation

Spring 2025

Department 1

Environmental Studies

Abstract

In the Western United States, understanding the role of reburns, or repeat wildfires, has become a topic of increased interest as the damages caused by wildfires have risen. While some forests are adapted to frequent burns, others have fire regimes characterized by few or infrequent burns. While all fires alter ecosystems, reburns have been found to specifically lower seeding probability and accelerate or start the shift from forests to shrublands. Despite these ecological impacts, the temporal and spatial trends of reburns remain understudied. Using Google Earth Engine, I analyzed the Composite Burn Index (CBI) dataset to see if reburns are becoming more common, which ecoregions they are occurring in, at what severity they are occurring at, and whether they are more common on federal or non-federal land. From 1996 to 2021, reburns were found to have become significantly more common across the Western U.S., both in total size and as a percentage of all burns. However, these findings varied based on ecoregion, with some showing no or insignificant growth while the Arizona / New Mexico Mountains saw a substantial increase. Nearly 40% of these reburns were found to occur in forest types where frequent fires likely did not occur historically and thus may not be ecologically beneficial. The severity of reburns varied widely, but reburn severity tended to be similar to that of the initial burn. Reburns were also more likely to occur on federal land than on non-federal land, particularly on U.S. Forest Service lands. This research gives important insights into how climate change may be altering vegetation and weather, which influence fire regimes, making more areas prone to frequent burns. It also has important implications for wildfire management, especially regarding how prescribed burns may influence the likelihood and severity of future burns.

Comments

Written for ES 460: Individualized Study-Research

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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