Changing Large Wildfire Dynamics in the Wildland–Urban Interface of the Eastern United States: Research Brief

As development continues to expand into fire-prone landscapes, the eastern United States is experiencing notable shifts in wildfire patterns. Weidig and colleagues analyzed four decades of wildfire records to examine how large wildfire dynamics have changed across eastern ecoregions, with a particular focus on the wildland-urban interface (WUI)–areas where homes and wildlands meet. The study assessed trends in wildfire size, frequency, and seasonality both within and outside the WUI, providing new insights into how changing land use and fire weather are reshaping fire regimes in this land-use type. The authors found that wildfire activity has increased across much of the eastern U.S., with the number of wildfires having grown over time–especially in the southeastern coastal plain. Nearly half of all recorded wildfires across the eastern U.S. occurred within the WUI, most of which occurred in the Central Appalachian region. While these WUI fires pose the greatest threat to human life and property, the most extensive fires typically occurred outside of developed areas. The southeastern coastal plain saw the most large wildfires occur outside the WUI, yet most wildfires within and outside the WUI in the region were human-caused. The timing of wildfires also shifted, with more fires occurring earlier and later in the year–indicating a lengthening fire season. These trends suggest that interactions among vegetation growth, human development, and changing weather conditions are driving more frequent and widespread wildfires in the eastern U.S. For fire managers in the southern region, this study supports the use of prescribed fire as a proactive tool for reducing fuel loads and mitigating wildfire risk near expanding communities. As fire seasons lengthen and weather windows for prescribed burning become less predictable, managers may need to adopt more flexible and adaptive approaches to maintain desired fire frequencies. Moreover, the finding that most wildfire ignitions in the southeast are human-caused underscores the value of cross-jurisdictional coordination and community outreach in the WUI to promote fire-adapted landscapes. Nevertheless, continued application of prescribed fire remains essential for sustaining ecosystem resilience and reducing the potential for catastrophic wildfires.

Fire Lines