Influence of grading intensity on ground cover establishment, erosion, and tree establishment on steep slopes

In 1991, a 5-year study was established in eastern Kentucky to evaluate the effect of surface grading intensity on ground cover development, erosion, and tree establishment. The study included three grading treatments. The moderately graded treatment consisted of backfilling a 40% slope and back-blading with a Caterpillar D-9 bulldozer to create a smooth slope. The intensively graded treatment involved additional back-blading passes, followed by tracking-in with D-9 bulldozers. The roughly graded treatment was created by ripping plots with a 36-in ripping bar pulled directly downslope with a D-9 bulldozer. Each plot was installed on the slope, with a level area at the base of each plot. Five species of trees were planted in each plot (white pine, loblolly pine, sycamore, sweetgum, and yellow-poplar), and the entire area was hydroseeded with a tree-compatible ground cover. Erosion was measured monthly using erosion rods. Ground cover was measured along a transect after the first growing season. Total ground cover averaged 82% after 3 years and was not affected by grading treatment, although there was a significantly higher amount of legume cover on the roughly graded plots. Erosion was highest on intensively graded plots. Tree survival varied by species. Average survival was best for sycamore and poorest for white pine. Growth of sycamore and loblolly pine was significantly reduced by the intensive grading treatment