Structural Features of a Post-Clear-Cutting Ecotone between 90-Year-Old Bilberry Spruce Forest and 35-Year-Old Herbs-Forbs Deciduous Stand

Abstract

In a natural regeneration process, a community dominated by birch and aspen forms in the site 35 years after a bilberry-type spruce stand is logged down. The newly formed ecotone complex consists of four zones, each characterized by certain features of the ground vegetation and epiphytic vegetation structure. The transitional zones and the mature bilberry-type spruce forest feature a clear dominance of boreal dwarf shrubs (bilberry and cowberry). Another feature of the transitional zone is a greater role of hygrophytic mosses of the genera Polytrichum and Sphagnum. Meanwhile, the true mosses Pleurozium schreberi and Hylocomium splendens dominate under spruce forest canopy, and the moss cover in the young deciduous stand is virtually nonexistent. The structure of epiphytic vegetation depends on the habitat conditions—the surface of tree trunks in the transitional zone is better lit and drier than inside the tree stand, which results in a higher abundance of epiphytic lichens of the genus Cladonia. The deciduous–coniferous fine root biomass ratio is dependent on the tree stand structure and is unrelated to ecotone zones. Overall, studies have demonstrated that transitional zones have certain characteristic ecological and community features, which persist for a long time after tree stand removal.