Damage Caused by Wheeled Skidders on Cambisols of Central Europe

Machine traffic and timber skidding significantly affect the soil surface and soil properties. The effects are mostly negative and result in soil erosion, worsening of soil properties and inhibition of the growth of roots and soil organisms. In this study, we evaluated forest soil damage caused by the HSM 805 HD wheeled skidder during timber skidding in selected forest stands in the School Forest Enterprise in Zvolen. We estimated the limits for operation of forest machines in the stands and evaluated the moisture content and bulk density of the soil, CO2 concentration in the upper layer of the soil, determined the soil texture, Atterberg limits and critical moisture using the Proctor test, CBR test and examining the depth of ruts on skid trails. The measurements were taken from undisturbed forest soil unaffected by skidder traffic, the ruts and between the ruts. The results showed significant differences between the values of soil samples from undisturbed soil and the soil affected by the skidder. The exceeding of CO2 concentration limits and bulk density in the soil from the ruts were recorded in both stands. The methods used present the basic methodology for evaluating the effect of logging machinery on forest soil and for setting limits that will allow or prohibit the operation of logging machinery according to forest stand conditions. The moisture content of soil, when it changes from the solid to plastic phase, was chosen as the limit for machine operation. This value is also easy to measure.