Soil Surface Condition Following Tractor and High-Lead Logging in the Oregon Cascades

Abstract Soil surface condition and bulk density were investigated after tractor and high-lead logging. Surface area of four clearcut units was classified into four disturbance classes. High-lead and tractor areas had about the same proportion of the slightly disturbed and deeply disturbed classes (approximately 23 percent and 9 percent, respectively). The tractor-logged area had about three times more area within the compacted class than did the high-lead (27 vs. 9 percent) and a corresponding decrease in the amount in the undisturbed class (36 percent of tile tractor area vs. 57 percent after high-lead logging). Surface soil bulk densities of samples from undisturbed and slightly disturbed areas were the same as prelogging values. Values for both the deeply disturbed and compacted classes were significantly higher, indicating a decrease in soil porosity. Compaction caused by tractor logging undoubtedly results in some increase in runoff and erosion. However, these undesirable effects are minimized if slopes do not exceed 20 to 30 percent and skidroads are located on the contour.