Structure of a Middle Taiga Vaccinium Spruce Forest after 40 Years since an Intensive Selective Cut in the Fish Spawning Protection Zone of Lake Onega

The condition and structure of the stand formed over 40 years after high-intensity, even, gradual logging in the fish spawning protection zone of Lake Onega were studied. In the test plots laid out in 1982 before logging in a relatively uneven-aged mixed spruce forest of the vaccinium type of forest of III-IV quality class with a wood stock of about 220 m3 ha-1, the proportion of spruce was 40%, and the density of medium and large spruce undergrowth was about 1 thousand trees ha-1. As a result of logging, the reserve decreased by 50-70%, and the proportion of spruce in it was 60-65%. By 2023, stepped-closed mixed stands with a predominance of spruce and a total reserve of 250-300 m3 ha-1 were formed on the logging site. Half of the available stock is concentrated in the lower part of the canopy, under which there are more than 3 thousand trees ha-1 of spruce undergrowth. The spatial variability of density, stock, species composition of the stand and natural regeneration in the context of ensuring the sustainability of the stand is studied. Data on the dynamics of increment, large woody debris, age structure of the stand and undergrowth are analysed. The role of the technological network in the formation of heterogeneity of the stock, increment, species composition and undergrowth was clarified. The species composition and projective cover of the living ground cover as an indicator and factor of the dynamics of the stand are studied. Statistical relationships between the structural elements of the phytocoenosis are revealed, contributing to the understanding of its development and stability. The correspondence of the stand formed after felling to the main criteria for identifying biologically valuable forests is shown. Based on the results of the analysis of the obtained data and literary sources, a conclusion was made about the prospects of continuing selective management in the interests of further growth and sustainability of the spruce forest and the performance of its protective functions.