2 research outputs found

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

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    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

    Nitrogen and Boron Dosage Effects on Arginine Accumulation in Scots Pine Needles

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    Free arginine (Arg) content was observed to multiply when the level of nitrogen (N) nutrition was high, and additional fertilization with boron (B) potentiated this effect. Owing to this feature, conifers can be suggested for use as bioproducers of Arg. Concentrations of Arg in relation to N and B fertilization needed to be better understood. The effect of soil fertilization with N and B on accumulation of these elements and free Arg in one-year-old needles of 16-year-old Scots pine (Pinus sylvestris L.) trees was determined in this study. Plantations were fertilized with doses of N from 0 to 1000 kg ha−1 and B from 0 to 6 kg ha−1. Fertilization with 3 kg ha−1 B at N doses of 200–500 kg ha−1 stimulated the accumulation of N in needles of up to 3.1–3.6% dry weight (DW). The level of Arg in needles increased from 74.7 to 175.9 μmol g−1 DW at these levels of N and B