Increasing the number of forest machinery passes and removing the organic layer reduces soil respiration on skid trails within clearcuts of boreal coniferous-deciduous stands

The movement of logging equipment damages forest soils along skid trails (ST), adversely affecting soil functions. Soil respiration (SR) is a key indicator of soil vitality, and assessing it in relation to the degree of anthropogenic disturbance improves understanding of the impacts of timber harvesting on the carbon cycle in ecosystems regenerating after clear-cutting. This study aims to characterize the effect of the number of forwarder passes and rut levelling on soil respiration of STs in a coniferous-deciduous clearcut in the Eastern European Plain. The study was conducted during the May–October over the first three years following clearcutting. Soil respiration was assessed on STs subjected to three forwarder passes (3ST), ten passes (10ST), and ten passes followed by rut levelling and forest floor removal (10 R). Undisturbed soil cover elements (UDE) were also investigated. Fewer forwarder passes had no significant effect on SR of 3ST compared to UDE in the initial two years post-harvest. Conversely, increased soil loading adversely affected SR from the 10ST, resulting in a reduction of 12–66 % during the first two years following harvesting. Inter-annual variation analysis revealed a decrease in the soil respiration rate in the second year post-clearcutting, while an increase was observed in the third year from 10ST, comparable to UDE, associated with the gradual overgrowth of herbaceous and tree vegetation. Soil respiration was reduced by 41–91 % in 10 R compared to UDE. The results obtained will be used to assess the carbon cycle of clearcuts during regenerative succession. For minimizing the negative impact on soil during logging requires selecting the logging area size to reduce the number of forwarder passes.