Controls on the Spatial Distribution of Near-Surface Pyrogenic Carbon on Hillslopes 1 Year Following Wildfire
Affiliation
Department of Geosciences, University of ArizonaDepartment of Environmental Science, University of Arizona
Arizona Geological Survey, University of Arizona
Issue Date
2021
Metadata
Show full item recordPublisher
Blackwell Publishing LtdCitation
McGuire, L. A., Rasmussen, C., Youberg, A. M., Sanderman, J., & Fenerty, B. (2021). Controls on the Spatial Distribution of Near-Surface Pyrogenic Carbon on Hillslopes 1 Year Following Wildfire. Journal of Geophysical Research: Earth Surface, 126(6).Rights
© 2021 American Geophysical Union. All Rights Reserved.Collection Information
This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.Abstract
Wildfire alters hydrologic and geomorphic systems, promoting increases in runoff and erosion relative to unburned areas. As a result, pyrogenic carbon (PyC) produced by wildfires can experience substantial lateral redistribution from overland flow. Since landscape position helps to determine the fate of PyC, it is critical to understand the geomorphic factors that govern its lateral redistribution as well as the sensitivity of those factors to soil burn severity, which controls the magnitude of many wildfire-induced hydrologic and geomorphic changes. In this study, we quantified the spatial distribution of near-surface (0–5 cm) PyC on three hillslopes roughly 1 year after the 2018 Buzzard Fire in the Gila National Forest, New Mexico, USA. We then use hydrologic monitoring data, terrain analysis, and rainfall-runoff modeling to explain the observed spatial distribution of PyC. Near-surface PyC concentrations decreased from averages of roughly 12–8 g/kg as slope and unit stream power increased by factors of ∼2 and 4, respectively, on a hillslope burned at low severity. This suggests that susceptibility to runoff-driven erosion was a dominant control on the redistribution of PyC. In contrast, the spatial distribution of PyC in areas burned at moderate to high severity was independent of slope and unit stream power. We attribute this pattern to intense runoff and lack of canopy cover, which promoted erosion of PyC regardless of slope and landscape position. Results demonstrate that how wildfire-induced hydrogeomorphic changes can modulate the importance of terrain attributes in controlling the spatial distribution of PyC in upland landscapes. © 2021. American Geophysical Union. All Rights Reserved.Note
6 month embargo; first published: 20 May 2021ISSN
2169-9003Version
Final published versionae974a485f413a2113503eed53cd6c53
10.1029/2020JF005996