Runoff and sediment production in oak forests of the Sierra Madre Oriental, Mexico

Abstract

In natural conditions, undisturbed forest soils have high infiltration rates and runoff and erosion are relatively low, but these may be modified after burning. Infiltration capacity and soil aggregate stability tend to decline in soils of burned areas, which make them prone to increased infiltration and soil erosion. In this study, the effect of three post-fire conditions (high and moderate fire severity and unburnt) on hydrological and erosional properties was evaluated using rainfall simulation in oak forests of Sierra Madre Oriental, Mexico. Additionally, soil surface properties affecting runoff and sediment production were identified by means of regression trees. Average runoff, peak runoff and sediment production were greater in high fire severity plots than in moderate severity and unburned plots. Soil surface roughness, slope, litter cover and stone fragments cover were the main surface characteristics that influenced runoff in the studied burned areas. It can be concluded that fire severity and soil surface characteristics are fundamental variables to consider for a better understanding of hydrological surface processes in forests affected by wildland fires. These results can be used to identify priority mitigation and restoration areas in the region.