Evaluating Post‐Fire Salvage Logging Erosion Mitigation Treatments in the California Sierra Nevada, <scp>USA</scp>

ABSTRACT The effects of salvage logging on runoff and sediment delivery processes are not well understood. We used rill erosion simulation experiments for 3 years after the 2013 Rim Fire to understand how post‐fire salvage logging and mitigation practises affect runoff and sediment delivery rates. We assessed soil conditions, surface cover, runoff rates and sediment delivery rates on hillslope plots that were either burned at high severity (controls) or burned at high severity with additional logging treatments including no logging traffic, few pass or many pass skid trails, and skid trails that were treated with subsoiling or ‘drop and lop’ (added wood ground cover). Runoff and sediment delivery responses were generally lower in the controls and plots that were logged with no traffic than in plots that received heavy equipment traffic, regardless of the amount of traffic or whether a mitigation treatment was applied. Responses decreased for all conditions over the three‐year study. Logging traffic had the largest impact on soil disturbance and subsequent runoff and erosion. In all 3 years, the many pass plots had ~6 times the sediment concentration in samples compared to the control plots. The drop and lop treatment doubled the ground cover in the first post‐fire year compared to its treatment pair but did not effectively reduce runoff or sediment delivery. Subsoiling did increase infiltration but did not reduce bulk density or decrease runoff; it also did not increase sediment delivery or impact vegetation recovery. These findings will be useful in developing comparative modelling tools and in selecting mitigation strategies to reduce sediment delivery rates following the soil disturbance and compaction from post‐fire salvage logging.