Soil response to skidder trafficking and slash application
Ground-based timber harvesting systems are common in the United States. Harvesting machinery can negatively influence soils by increasing erosion and decreasing site productivity. Skid trails can become compacted and erosive. Slash applications to skid trails are effective for erosion control, yet few investigations have examined effects of slash on soil physical properties influenced by compaction. This research project has two objectives: (1) to compare and contrast the impacts of traffic resulting from a rubber-tired grapple skidder and a dozer using a variety of soil compaction indices, and (2) to compare effects of slash versus bare soil on skid trails trafficked by a rubber-tired grapple skidder and a dozer. The project was conducted within an upland hardwood/pine stand in the Ridge and Valley region. Skidder traffic changed both visual appearance and soil physical properties. The heavier skidder resulted in deeper visible ruts, greater increases in bulk density, and greater decreases in macro porosity when compared to the lighter dozer. This project also served as a pilot test for the AgTech sensor for forest trails. Results from sensors are briefly compared with traditional soil compaction indices. While no major relationships were found, the technology is promising for future research applications. Using slash as a means of ameliorating soil disturbance was not entirely conclusive as variation in cover had no effect on bulk density or porosity and mechanical resistance data were contradictory. Slash reduced increases in soil strength, and despite difference in sizes, the skidder and dozer resulted in similar changes in soil strength.