Contemporary patterns of prescribed fire and its risks and benefits to water quantity and water quality over the conterminous United States

Prescribed fire has emerged as an essential ecosystem management practice for maintaining forest health and mitigating wildfire risks. However, its spatio-temporal patterns and potential impacts on water quantity and quality remain poorly understood compared to those of wildfires. By analyzing the Monitoring Trends in Burn Severity database (1984–2022), we characterized distinct regional, seasonal and interannual dynamics of large prescribed fires relative to wildfires across the conterminous United States. We found the Southeast dominated the national prescribed fire regime, accounting for 78.6% of total prescribed fire occurrences and 70.7% of total burned area. Seasonally, prescribed fires primarily occurred in the spring, contrasting with wildfires that peak in autumn, particularly in the West and Southwest. Prescribed fires in the Southeast increased significantly from the early 2000s, peaking around 2010, then temporarily declined, whereas wildfires in the West exhibited an overall upward trend with substantial interannual variability. Our synthesis of studies from 1969 to 2024 showed that prescribed fire could potentially reduce evapotranspiration, but increase surface runoff through alterations of vegetation structure, rainfall partitioning, soil properties, and flow generation processes. Additionally, prescribed fire may influence water quality by modifying soil nitrogen dynamics, dissolved carbon, erosion, and sediment transport. However, these impacts are typically short-lived and can be effectively mitgated through site-specific strategies, supporting the use of prescribed fires as as a safe and practical management tool. To this end, we developed an adaptive framework that guides prescribed burning by balancing its ecological and hydrological benefits against potenital risks, thereby promoting sustainable forest management, reducing wildfire risk, and protecting water resources.

Duke Scholars

Author Wenhong Li Earth and Climate Sciences