Influence of thinning operations on the hydrology of a drained coastal plantation watershed
Forest management activities such as harvesting, thinning, and site preparation can affect the hydrologic behavior of watersheds on poorly drained soils. The effects of thinning on hydrology are presented for an artificially drained pine plantation paired watershed in eastern North Carolina. Outflow and water table depths were monitored over a 3-year study period from paired 40- and 16-ha 15-year old loblolly pine (Pinus taeda L.) plantations located in Washington County near Plymouth, North Carolina. Thinning increased daily outflow, peak flow rates, and had no significant impact on water table depths. Mean daily outflow doubled and peak flow rates increased 40 percent on the thinned watershed in relation to the control. These differences in hydrologic behavior are primarily attributed to the thinning operation which resulted in reduced evapotranspiration.