Effects of timber management on the hydrology of wetland forests in the southern United States

The objectives of this paper are to review the hydrologic impacts of variou s common forest management practices that include harvesting, site preparat ion, and drainage. Field hydrological data collected during the past 5-10 y ears from ten forested wetland sites across the southern US are synthesized using various methods including hydrologic simulation models and Geographi c Information Systems, Wetland systems evaluated include red river bottoms, black river bottoms, pocosins, wet mineral flats, cypress domes, and pine flatwoods. Hydrologic variables used in this assessment include water table level, drainage, and storm flow on different spatial and temporal scales. Wetland ecosystems have higher water storage capacity and higher evapotrans piration than uplands. Hydrologic impacts of forest management are variable , but generally minor, especially when forest best management practices are adopted, A conceptually generalized model is developed to illustrate the r elative magnitude of hydrologic effects of forest management on different t ypes of wetlands in the southern US. This model suggests that in addition t o soils, wetland types, and management practice options, climate is an impo rtant factor in controlling wetland hydrology and the magnitude of disturba nce impacts. Bottomland wetlands, partial harvesting, and warm climate usua lly offer conditions that result in low hydrologic impact. (C) 2001 Elsevie r Science B.V. All rights reserved.