Hillslope Treatments

Hillslope postfire rehabilitation treatments, intended to reduce surface runoff and keep soil on the hillslope, can generally be categorized into three groups:

1. seeding for vegetative regrowth and invasive weed control
2. mulches or ground covers
3. erosion barriers and trenches that physically hold runoff and sediment

The effectiveness of any hillslope rehabilitation treatment depends on the actual rainfall amounts and intensities—especially in the first 1-3 years after the fire. For example, on the 2000 Bobcat Fire in the northern Colorado Front Range, none of the 3 test treatments (dry straw mulch, seeding, and contour-felled log erosion barriers) significantly reduced sediment yields in the first year after the fire. During the first postfire summer, an intense rain event (I₃₀= 2 in hr^-1 or 48 mm hr^-1) overwhelmed all the applied treatments, resulting in the same or greater sediment yields on treated plots as the untreated control plots. Some treatments did reduce sediment yields in the second year after burning, when rainfall occurred over several smaller events (Wagenbrenner 2003).