Post-fire mulching for runoff and erosion mitigation

Abstract

article i nfo Mulch treatments often are used to mitigate post-fire increases in runoff and erosion rates but the comparative effectiveness of various mulches is not well established. The ability of mulch treatments to reduce sediment yields from natural rainfall and resulting overland flow was measured using hillslope plots on areas burned at high severity following four wildfires in the western United States. Wheat straw mulch, wood strand mulch, and hydromulch were evaluated along with untreated control plots on multiple fires for 4 to 7 years after burn- ing. Needle cast from fire-killed conifer trees was evaluated in an area of moderate burn severity at one fire, and seeding with genetically native seed was tested, with and without hydromulch, at another fire. Rainfall, ground cover, and soil water repellency were measured in each treatment site at all 4 fires. Mean sediment yields on the control plots ranged from 0.3 to 7.5 Mg ha −1 in the first post-fire year, from 0.03 to 0.6 Mg ha −1 in the second, and from 0 to 0.4 Mg ha