Changes in Composition and Structure of the Lower Storeys Vegetation on Cutting Areas with Varying Degree of Technogenic Stress in the Middle Taiga of the Komi Republic

Logging is one of the main factors changing boreal forests in the European part of the Russian Federation. The task of assessing the vegetation’s restoration during the initial stages of post-logging successions is complicated by the presence of heterogeneous areas with varying degrees of technogenic stress and disturbance of the lower vegetation layers in each clearing. The objective of this work is to assess the nature of changes in the composition and structure of the lower vegetation storeys in areas with varying degrees of technogenic stress during the early stage of restoration succession (1-3 years) after experimental logging of bilberry-green moss spruce forest in the middle taiga of the Komi Republic. During the experiment, three forest swaths and six skid roads with different levels of technogenic stress, which were determined by the number of passes of wheeled vehicles, were examined. Track alignment was carried out on three skid roads. Geobotanical descriptions were being made for each technological element of the clearing over a period of three years. In the swaths and skid roads, the projective cover of the main storeys was restored to the initial values within three years after the logging, but significant changes occurred in the composition of the dominant species’ complex. The leading positions were occupied by light-loving species, primarily Avenella flexuosa. In the skid roads with track alignment, the restoration of the vegetation cover began in the third year of the restoration succession, and the vegetation is very mosaic, which, along with the high level of species diversity, may indicate a random nature of these plant groups’ formation at this stage of succession. Our results indicate that the level of technogenic stress during logging affects the rate of subsequent restoration of the lower storeys vegetation. In the skid roads, both in the tracks and in the spaces between the tracks, areas with three and ten passages differed in the composition and structure of plant communities. This was primarily demonstrated by the strengthening of the cenotic positions of weed species and hygrophyte species in the more disturbed areas. Straightening of the skid roads’ tracks without additional reclamation techniques has led to a slowdown in the process of vegetation restoration.