U.S. Joint Fire Science Program


Date of this Version


Document Type



Final Report: JFSP Proposal P06-3-4-21


US government work.


Legal challenges have delayed numerous post-fire salvage logging operations, which often results in lost economic value of the burned timber and unrecovered legal expenses. The scientific literature has shed little light on the additive effect of salvage logging operations on post-fire runoff, erosion, flooding, and sedimentation. Hence, there is an urgent need to better understand the impacts of post-fire salvage operations so that land managers can evaluate the relative and cumulative effects of different salvage logging practices. Intensive, multi-scale studies are needed because the effects of post-fire logging are superimposed on the effect of wildfires; rates and processes change according to the spatial and temporal scales of the investigation; and the studies to date indicate tremendous variability in the effects of post-fire salvage logging with the type and extent of the logging, site characteristics, and climatic conditions. To address this need, the current project was established in the Northern Rockies to integrate experiments at the hillslope and small watershed scale that focus on erosion processes. Replicated plots were used to measure sediment production rates from burned and unlogged plots, logged areas, tracked areas due to ground-based logging, and tracked areas with added slash as an erosion control treatment. Measured erosion rates were related to detailed measurements of site characteristics including ground cover, rilling, water repellency, amount of area disturbed due to salvage logging operations, number of passes of logging equipment, soil compaction, and the number and type of erosion mitigation practices (e.g., application of logging slash, mulch, and water bars). Runoff and sediment yield data were collected from two pairs of small watersheds to determine how salvage logging affects runoff, peak flow, and erosion rates, and whether the erosion estimates from the hillslope plots can be extrapolated to the small watershed scale. Rill simulation studies were conducted on three sites affected by ground-based salvage logging to evaluate the various types of equipment and identify site factors that affect runoff and erosion rates.