Effects of clearcutting and site preparation on stormflow volumes of streams in Pinus elliottii flatwoods forests

Abstract

Three operational-sized watersheds in pine flatwoods of the Lower Coastal Plain in north Florida were isolated and continuously monitored for 3 1 2 years. Recording flumes assessed quantity of runoff water. After 1 year of calibration monitoring, two of the watersheds were, harvested, site-prepared, and planted under distinct harvest and regeneration practices. Minimum practices, imposed on one watershed, consisted of manual shortwood harvest of pinelands, roller drum chopping of harvest residues and residual understory, bedding, and planting. Maximum practices, imposed on another, consisted of tree-length logging of pinelands with heavy equipment, extraction of lightwood stumps, burning and windrowing of logging residue and residual understory, harrowing, bedding, and planting. Both silvicultural systems increased stormflow volumes; maximum practices moreso. Under both systems stormflow volumes apparently increased immediately following tree harvests. The increase persisted through site preparation, planting, and subsequently for 1 1 2 years without further detectable change. Results of this and two earlier reports on the effects of silviculture on hydrologic regimes of flatwoods forests are reviewed and summary conclusions drawn.