Abstract
The amount of rainfall and soil loss from tractor logging roads were measured at 9 test road sections for two or three years after logging. Applying Universal Soil Loss Equation to estimate amount of soil loss, the soil erodibility factor was calculated. The correlation analysis showed that the factor related to the period after logging and the height of cut slope. A equation to calculate the soil erodibility factor was derived by multiple regression analysis. As a result, it became possible to more easily estimate the amount of soil loss from the tractor logging roads. To minimize the amount of soil loss from the tractor logging roads, the cut slope should be low.
