SEDIMENT FLUX ASSOCIATED WITH OFF-ROAD VEHICLE (ORV) USE IN A MID-LATITUDE FOREST

Much of the recreational use of off-road vehicles (ORVs) in the eastern United States occurs in national forests. This use of the forest land is typically well established, expanding, and officially sanctioned. Nevertheless, the physical impacts of ORVs on mid-latitude forest lands have not been studied as much as ORV effects in arid and coastal settings. This research investigates the impact of ORVs on hillslope sediment dynamics in the Athens unit of Wayne National Forest in southeastern Ohio. The study area lies within the Appalachian Plateau province and is underlain primarily by Late Pennsylvanian shales, siltstones, sandstones, limestones, and coals of the Allegheny and Conemaugh Groups. Topography consists of stream-dissected ridges and displays an average local relief of about 70 m. Each year, the Forest Service allows ORV use in the Athens unit from April 15 to December 15, and only on designated trails.

A dense network of ground height, penetrometer resistance, and penetrometer depth data was collected for this study from forest and trail locations at four ORV and two non-ORV trail sites within the Athens unit. Complete sets of measurements were acquired at the height of the ORV season, at the end of the ORV season, and near the end of the off-season. Statistical tests are used to separately compare ground-height change and the penetrometer observations for forest vs. trail locations, ORV vs. non-ORV trail sites, and one time period vs. another. Results reveal considerable sediment flux at the ORV sites. Net erosion on the ORV trails during the studied part of the riding season was quantitatively offset by net deposition there during the off-season. Meanwhile, trail-adjacent forest land experienced aggradation in both periods, but especially during the ORV season. Calculations suggest that sediment erosion from a 2.45 m x 60 m ORV trail segment may be as high as 15.4 m³ over the entire eight-month ORV season.