From burned slopes to streams: How wildfire affects nitrogen cycling and retention in forests and fire-prone watersheds

Abstract

Wildfire is a major driver of nitrogen (N) cycling and export from terrestrial to aquatic systems. While fire is a natural process in many watersheds, it can still degrade water quality by rapidly flushing N to streams. This can be particularly problematic in watersheds that experience high levels of N deposition or where climate change is promoting larger and more severe fires. The extent and duration of postfire N export, and the potential consequences for downstream water quality, depend on how N inputs, internal cycling, and outputs vary before, during, and after fire. Here we review the major factors controlling N cycling and retention in forests and adjacent shrublands, and how fire modifies these controls. We connect burned slopes to streams to describe how fire exports N to aquatic environments. We also consider the implications for municipal watersheds and water resources management. We close by identifying critical knowledge gaps in projecting how fire will affect watershed N cycling and retention in the future.

Citation

Gustine, Rebecca N.; Hanan, Erin J.; Robichaud, Peter R.; Elliot, William J. 2021. From burned slopes to streams: How wildfire affects nitrogen cycling and retention in forests and fire-prone watersheds. Biogeochemistry. https://doi.org/10.1007/s10533-021-00861-0.