Effect of Clear‐Cut Silviculture on Dissolved Ion Export and Water Yield in the Piedmont

Abstract

A paired watershed experiment in Putnam County, Georgia, was carried out from 1973 to 1980 to determine the effects of a typical southern clear‐cut operation on water quality, timing, and yield. This report shows that increases in monthly exports of dissolved N, P, K, Ca, Mg, Na, TKN, and total electrolytes were short‐lived and less than 0.5 kg ha−1 month−1 and may therefore be considered minor for practical purposes. Stream water concentrations were mostly diluted by clear‐cutting, but a monthly water yield increase of 1 to 2 cm flushed an extra 0.15 kg ha−1 month−1 of nitrate‐nitrogen from the basin during a 2‐year period following harvest. Twenty surrounding forested basins (7 to 165 ha in area) were sampled monthly for 1 year, showing that the experimental pair was representative of the general levels of dissolved ions in forested Piedmont streams. Results suggest that clear‐cut silviculture in this region will neither reduce soil fertility by flushing ions into streams nor eutrophy stream water.