The impacts of clearcut harvesting and four intensities of mechanical site preparation were evaluated in the Virginia Piedmont using gauged watersheds. The four treatments were: 1) control, 2) chop and burn, 3) shear-disc, and 4) shear, rake-pile, disc. A combination of soil solution, streamwater and soil sampling and a series of soil incubations, both laboratory and <i>in situ</i> monitored changes in the treatment areas following site preparation. Available nitrogen reserves decreased substantially in the shear, pile, disc treatment area but increased in the chop and burn and shear-disc treatment areas following site preparation. Increased soil moisture and temperature following disturbance stimulated nutrient mobilization. Soil solution KCI extractable and <i>in situ</i> soil incubations all indicated that nitrogen mineralization was greater in the site prepared watersheds. Among the site prepared areas, treatment response followed a site preparation intensity dependent gradient. Fifteen, 26, 20 and 45% respectively of the available nitrogen reserves were mineralized within one year following site preparation in the control, chop and burn, shear-disc and shear, pile, disc watersheds. Streamwater nutrient export also increased following disturbance. Soil erosion increased in a 1:6:60 proportion in the chop and burn, shear-disc and shear, pile, disc treatment areas. Higher soil erosion led to increased sediment export in the site prepared areas. / M. S.