Erosion Studies in Burned Forest Sites of Georgia

Abstract

Soil erosion from disturbed forestlands is of great concern to forest managers, soil scientists and hydrologists. The problem arises not only from detrimental effects of erosion on soil productivity but also by the adverse effects on water quality. Site preparation techniques such as burning, root raking and disking are most frequent causes of disturbance to forestlands. Burning is a common practice used to control understory hardwood, reduce fuel hazards, improve wildlife habitat and prepare seedbeds and sites for planting (Van Lear 1985). Burning, however, can increase the erosion rate by two different mechanisms. First, by destroying the surface litter layer and possibly the underlying fibrous root layer, the mineral soil is exposed and the forces resisting erosion are reduced. Second, burning can decrease the infiltration rate by creating a hydrophobic (non-wettable) condition (DeBano 1981), thus, surface runoff will increase and that increases the driving forces for erosion. Reliable and consistent data on the rate of runoff and sediment production from burned forest sites is not available in the South. This research is presented with two main objectives: (1) to assess the rate of erosion and runoff from a burned forest site in the Georgia Piedmont and how it changes with time for different levels of slope steepness, rainfall intensity, and antecedent moisture conditions, and (2) to present data on observations of the hydrophobicity (non wettability) phenomenon and discuss its significance on runoff and erosion production.