The Influence of Forested Streamside Management Zone Width and Harvest Level on Water Quality in the South.

C. Andrew Dolloff, USFS SRS, Blacksburg, VA, and Michael Aust, VA Tech, Blacksburg, VA

Forested streamside management zones (SMZs) are the single most effective BMP for protection and enhancement of water quality, channel stability, and aquatic biota. Despite numerous documented benefits, however, relatively little research has focussed on the characteristics of SMZs (e.g. width, structure, allowable activities) and influences on water quality and aquatic biota. As a result, Forestry Best Management Practices Manuals for southern states recommend a bewildering array of SMZ widths and harvest levels. The goal of this research is to determine the adequacy of SMZ widths and harvest levels as recommended by BMP manuals currently in use across the South. We will document how specific activities influence water quality and other attributes related to ecosystem health and function. In brief, experimental units will be established within each small subwatershed selected for study. Both before-after and upstream-downstream effects will be investigated on each experimental unit. The treatments will occur in two zones adjacent to stream channels: one, outside boundaries determined by existing guidelines for an SMZ, and another outside boundaries located half-way between the recommended guideline and the stream channel. Treatments will consist of all activities typical of timber harvest and associated silvicultural operations, including (but not necessarily limited to) harvest, skidding, and site preparation. Results from this study will allow managers to recommend acceptance of current SMZ specifications where suitable, reduction of SMZ widths and harvest restrictions where reasonable, or increasing SMZ widths and decreasing harvest levels where necessary.