Applying RUSLE 2.0 to burned forest lands: An appraisal

Abstract

Forestlands disturbed by wildfire commonly constitute major and long-lasting sources of sediment that degrade water quality and cause siltation. Postfire restoration of the resistance to erosion of the forest soil is largely controlled by the rate of regrowth of vegetation and may take several years to return to prefire levels, particularly in areas of high-severity burns in semiarid climate. Time-instantaneous prediction techniques such as the Universal Soil Loss Equation (USLE) fail to describe the long-term effect. The latest version of the Revised Universal Soil Loss Equation (RUSLE version 2.0) includes a time-varying option that can model seasonal or pluri-year variations in biomass and other factors; also, it has revised governing equations and an updated database. RUSLE 2.0 claims to be land-use independent and, thus, it should apply to burned-forest lands with proper input for forest vegetation. This paper discusses this matter and concludes there still exist in RUSLE 2.0 built-in routines and parameters inherited from its agricultural application that hinder its use on burned-forest soils. Moreover, many forest lands are characterized by soil textures and slope gradients that fall near, or outside, the limit of the database used for validating USLE/RUSLE, a condition that may counter RUSLE´s overall improvement in precision and accuracy.