Influence of Ponsse Gazzelle forwarder passes on the soil environment and soil deformation.

During the harvesting and skidding process, machine runs have a strong influence on the soil environment. The study analyzed the influence of 20 runs of the Ponsse Gazzelle forwarder on the change of soil compactness, moisture and deformation. The research were carried out in Gidle Forest District, located in southern Poland. Analyzed areas was differing in soil type and hydrological conditions. On the investigated forest areas control sections were established for measurements.
The data of changes in soil compactness were gained by using a handheld penetrometer at a depth of 10 and 20 cm. The soil compactnes were measured after each forwarder pass. Soil moisture was also assessed at a depth of 10 and 20 cm before the start of the forwareder operation, and after 20 passes. To obtain data for determining soil deformation UAV were used. Terrain models were created using Agisoft Metashape software. From the generated 3D terrain models, changes in the cross-sections of operational routes were determined.
The data were subjected to statistical analysis to determine the relationship between the rate of changes in soil and terain conditions. The increase of soil compactness was linear on all the examined plots. Statistically significant differences were found in the soil compaction rate.
The average decrease in humidity after 20 forwarder runs on the tested sections was 39%.
Correlation analysis showed a moderate relationship with the extent of soil deformation and the type of soil and the type of forest habitat.