In the thesis, we have investigated soil damage after a single pass of single grip harvester through undisturbed forest and its relationship with the physical and chemical properties of the soil. At selected sites (Koče 1, Koče 2, Smuka, Sveti Peter), we measured wheel track depth, soil penetration resistance and soil water content, and collected soil samples for laboratory analyses. We focused on the influence of texture, organic matter, and carbonates, and pH on soil plasticity, as well as on factors affecting wheel track depth (slope, number and diameter of trees, presence of rocks and stones, thickness of organic horizons, soil depth, soil plasticity, etc.). Soil plasticity was first determined using a set of samples with varying textures typical of Slovenian forest soils, followed by analysis of soil samples from the studied forest sites.
We found that soil plasticity significantly increases with higher clay and fine silt content, while wheel track depth increases with higher soil moisture and lower total thickness of the organic horizons. The average wheel track depth after a single pass of the logging machine across all locations was 6.41 cm, with the deepest rut measuring 13.50 cm and the shallowest 1.50 cm. The greatest soil damage was recorded where the water content exceeded the upper plastic limit.
The results contribute to a better understanding of soil sensitivity to mechanical stress and support more sustainable forest harvesting planning.
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