Pyrogenic carbon (PyC) is an incomplete combustion by-product with longer soil residence times compared with nonpyrogenic components of the soil carbon (C) pool and can be preferentially eroded in fire-affected landscapes. To investigate geomorphic and fire-related controls on PyC erosion, sediment fences were established in three combinations of slope (high 13.9-37.3%; moderate 0-6.7%) and burn severity (high; moderate) plots within the perimeter of the Rim Fire in 2013, Yosemite National Park, California, USA. After each major precipitation event following the fire, we determined transport rates of total sediment, fine and coarse sediment fractions, and C and nitrogen (N). We measured stable isotope (δ 13 C and δ 15 N) compositions and 13 C-nuclear magnetic resonance spectra of soils and eroded sediments. The highest total and fine (<2 mm) sediment transport in high severity burned areas correlated with initial discharge peaks from an adjacent stream, while moderate burn severity sites had considerably more of the >2 mm fraction transported than high burn severity sites. The δ 13 C and δ 15 N values and 13 C-nuclear magnetic resonance analyses indicated that sediment eroded from moderate severity burn areas included fresh organic matter that was not as significantly affected by the fire, whereas sediments from high severity burn areas were preferentially enriched in PyC. Our results indicate that along a single hillslope after the Rim Fire, burn severity acted as a primary control on PyC transport postfire, with slope angle likely playing a secondary role. The preferential erosion of PyC has major implications for the long-term persistence of PyC within the soil system.

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Tuolumne Meadows, in the high country of Yosemite National Park, California, is a renowned natural and recreational resource noted for its scenic beauty, wildlife, and as a place of peace and tranquility. It attracts large numbers of visitors from around the world, and its importance is recognized by its designation as part of the Tuolumne Wild and Scenic River Final Comprehensive Management Plan. In keeping with this designation, management decisions are made with respect to biologic, geologic, cultural, scenic and recreational values with the purpose of preserving the Tuolumne River in free-flowing conditions, and to protect water quality. Part of the management plan is to monitor streambank dynamics in Tuolumne Meadows and to make science-based decisions regarding management and restoration efforts. This report provides scientific information towards these objectives.

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