RECOVERY OF THE SOIL AND PLANT COVER IN THE SKID TRAILS AFTER THINNING IN MYRTILLUS TYPE FORESTS OF THE NORTHERN TAIGA

Disturbance of soil and plant cover caused by logging operations results in various damages and can give rise to soil degradation and plant succession. We studied the recovery of soil and plant cover in the damaged skid trails of different periods after two-stage thinning of the Piceeta myrtillosum type forest. Thinning was conducted in 1973 and in 2002. The in-situ soil cover is represented by podzolic light loamy soil overlying heavy moraine loam. Tree-felling was carried out using a chainsaw, and tree-length skidding was carried out using a TDT-55 cable skidder. We studied the species composition and species ratios for different ecological groups of grass-shrub and moss layers, forest litter formation and soil properties and found higher plant species diversity in the skid trails and dissemination of the wetland group species, with Sphagnum mosses being indicators of swamping. These features provide thicker forest litter in the skid trails rather than in cut strips in the course of plant cover restoration. Due to swamping, the thickness of the forest litter increases in the process of succession. In the course of the natural recovery of the skid trails, the most significant changes of the soil were observed at the depth of 0–10 cm. The bulk density in the upper layer of the soil significantly reduces to 0.85–0.98 g.cm-3, when that of the cut strips is 1.19 g.cm-3. This results in organogenic substances associated with detritus decomposition and peat litter formation entering into the mineral part of the soil. At the depth of 10–20 cm, compaction caused by machinery passage is noted both 17 years and 46 years after thinning. In the myrtillosum forest type, the recovery of plant and soil cover typical of Piceeta myrtillosum in the conditions of the northern taiga subzone, was not observed for 50 years. Acknowledgements. The results of the plant renewal section were obtained within the Russian Science Foundation grant (project No. 23-76-01014, https://rscf.ru/project/23-76-01014/»). The results of the soil properties restoration section were obtained within within the grant of Ministry of Science and Higher Education of the Russian Federation (project No. MK-2622.2021.5). The authors thank N. Tsarev and A.-A. Dunaeva for their assistance in field data collection in the studied sites.