Effects of Forested Streamside Management Zone Widths and Thinning on Carbon Dynamics and Benthic Macroinvertebrates for Pine Plantations in the Piedmont of Virginia
To protect the integrity of the United State's waters, the Federal Water Pollution Control Act of 1972 promoted the establishment of Best Management Practices (BMPs) for forestry. A commonly used BMP is the reservation of Streamside Management Zones (SMZs). In this study the effectiveness of three different SMZ widths, 30.5 m (100 ft), 15.3 m (50 ft), and 7.6 m (25 ft), as well as thinning in 15.3 m SMZs were studied. The objectives of the study were to determine the effects these SMZ treatments had on carbon pools, carbon fluxes and environmental conditions in the SMZ. The benthic macroinvertebrate populations present within the stream were also examined because of their relationship to ecosystem carbon dynamics. Carbon storage in plant communities, litter layer, soil (upper 10 cm), and total organic carbon present (TOC) within streams were measured and quantified. Total CO₂ efflux and the major environmental drivers of soil CO₂ efflux, soil moisture and soil temperature, were monitored along a single transect within each SMZ. This study showed that carbon dynamics and stream biota (benthic macroinvertebrates) were not adversely effected by more narrow SMZ width and thinning within the SMZ. SMZ width did affect soil temperature, one of the environmental drivers affecting soil respiration. Based on these short-term results a 15.3 m SMZ with thinning or without thinning appears adequate to prevent changes in ecosystem function and water quality for forest applications.