Prescribed fire effects on sediment and nutrient exports in forested environments: A review

This review examines the impact of prescribed fire on the water quality variables (a) sediment load and (b) limiting macronutrients in forested environments globally. We aim to characterize the forested environments subject to prescribed fire, to discuss factors of the fire regime that contribute to water quality concerns, and to offer insight into the effect of precipitation timing and study scale on constituent exports. High fuel consumption during fire increases the risk of erosion and constituent export during precipitation, though high fuel consumption during prescribed fire is uncommon in forested environments. Small-scale studies examining sediment yield after prescribed fire may fail to capture the effect of landscape-scale spatial variability, and watershed-scale studies accounting for such variability are lacking. Although small-plot studies confirm that prescribed fire can alter hydrologic inputs, the environmental impact of these increases is minimal, particularly when compared with other land-use systems. Generally, prescribed fire is a beneficial and low-impact disturbance that likely improves fire-adapted forest health. However, gaps in knowledge exist at various spatial and temporal scales; this review suggests two avenues of future research, including (a) greater understanding of fire regime interactions that control surface runoff and erosion at the watershed scale, and (b) monitoring forest health and ecological function after prescribed fire rather than direct nutrient exports.