Hydrological and Erosive Effects of Prescribed Fire and Mulching with Fern Residues in a Mediterranean Pine Forest

This study has evaluated the short-term effects of prescribed fire and post-fire mulching using fern on soil hydrology in a pine forest of Southern Italy. Water infiltration (by rainfall simulations) and soil water repellency (SWR) were estimated immediately and one year after fire. Surface runoff volume and soil loss have been measured in experimental plots under natural precipitations throughout one year. The prescribed fire reduced the infiltration rates compared to the unburned soils. Mulching was not able to contrast this reduction, which, however, vanished over time. Immediately after the fire, the runoff (+375%) and erosion (+900%) significantly increased. The pre-fire runoff and erosion rates restored after about five months. Soil mulching with fern was effective to limit these increases (reductions in the runoff coefficients and soil losses by 60 to 90%, respectively). The prescribed fire induced SWR, which disappeared after one year. Overall, in a Mediterranean pine forest, post-fire management actions with a cheap mulch materials, as fern residues, are needed to control the negative hydrological impacts of prescribed fires in the short term.