Changes in soil bulk density resulting from construction and conventional cable skidding using preplanned skid trails

A harvesting system consisting of chainsaw felling and cable skidder extraction was studied to determine soil bulk density changes in a central Appalachian hardwood forest site. Soil bulk density was measured using a nuclear gauge preharvest and postharvest systematically across the harvest site, on transects across skid trails, and for a subset of skid trail transects closest to log landing after each of the first ten loaded machine passes. Bulk density was also measured in skid trails after their construction but prior to skidding. Bulk density did not change significantly across the harvest site, because the extraction equipment stayed on the preplanned skid trails. Bulk density increased on the skid trails as a result of construction by crawler bulldozer and during skidding. Bulk density in the skid trail increased by 30% because of construction by a crawler bulldozer. Fifty-five percent of the increase in bulk density attributable to skidding occurred after one loaded pass, and 80% of the bulk density increase was experienced after two loaded passes. Bulk density increased by only 5% between passes five and ten.