No 3 (2024)

The distribution of Picea abies (L.) H. Karst. undergrowth in three types of communities was studied: blueberry spruce forest with a relatively homogeneous tree composition, wood-sorrel-blueberry spruce forest with birch and aspen, and wood-sorrel-blueberry spruce forest with pine. Woody detritus as a microhabitat is represented not only by dead trunks and stumps (37 to 72 % of the undergrowth grows there), but also by the adjacent space (10—27 %), as well as by visually undetectable woody remains in the soil (1—11 %). In the blueberry spruce forest, the gaps occupy one third of the area with 46 % of the undergrowth, while the inter-crown zone occupies half of the area with 37 % of the undergrowth. The occurrence of the undergrowth is high in all zones (84, 73, 68 %), with clusters on dead wood (37 %) and in adjacent microhabitats (40 %). The density of undergrowth depends on the joint influence of factors — the highest values on deadwood in the gap space (1.0 specimen/m²), the average values — in the gap space near deadwood (0.6), in the inter-crown space on deadwood (0.5) and near it (0.5), as well as in the under-crown areas without deadwood (0.5), the lowest values — on “hidden” in the soil wood remnants (0.1—0.2). In wood-sorrel-blueberry spruce forest with aspen as part of the stand, the canopy organisation becomes more complicated, the undergrowth is almost evenly distributed across the canopy projection space categories with their ratio being 12:33:55 %. The maximum values of undergrowth occurrence and density are found on deadwood in the gap space (39 % and 0.7 pcs/m2), decreasing under the canopy (18 % and 0.3 pcs/m2). In wood-sorrel-blueberry spruce-pine forest the distribution of undergrowth is random: in all space categories the values of occurrence (31, 33, 30 %) and density (0.6, 0.5, 0.6 pcs/m2) are equally low, with the highest values of density found on deadwood under crowns (0.5 pcs/m2). Thus, the distribution of undergrowth in native middle taiga spruce forests is determined by a combination of factors: forest growing conditions, stand composition, diversity of microhabitats, including those formed by dead wood at different stages of decomposition.

Mountain and foothill forests provide many essential ecosystem services, but land use changes such as deforestation or, conversely, afforestation and reforestation can significantly impact their potential. Artificial forest stands can perform similar functions, but their effectiveness depends on species composition, age and management methods. Reforestation in these areas is critical to mitigating and adapting to climate change, increasing biodiversity and conserving water resources. Artificial forest stands in the North Caucasus were created with the aim of increasing the productivity of oak forests, and thanks to these measures, forest cover in the Republic of Adygea turned out to be significantly higher than in neighbouring regions. The purpose of the study was to assess the carbon-depositing and oxygen-producing role of artificial forest stands with oak in the foothills of the North Caucasus within the Republic of Adygea. It was found that in pure 70-year-old oak plantations the maximum increase in timber volume was 5.81 m³/ha per year, and the mixed 58-year-old oak stands were characterised by the minimum increase value, 1.04 m³/ha per year. The intensity of carbon accumulation and oxygen production was calculated through the increase in phytomass. The results showed that as the share of oak in the forest stand increased, production indicators and sequestration potential increased significantly. Artificial plantings of the Maikop forestry have accumulated in their above-ground and underground phytomass from 31 to 328 t C/ha. The annual accumulation of CO₂ by forests varied from 1.98 to 17.17 t/ha per year, and the annual production of O₂ was 1.71—12.79 t/ha per year. It has been proven that in order to increase the sequestration potential in the North Caucasus foothills, one of the most effective approaches may be targeted cultivation of pure and mixed forests with a predominance of seed oak, rather than the creation of a variety of multi-species plantations, including hornbeam and beech.

The city of Karabash (Chelyabinsk region) is an example of industrial environmental disasters. There is still a lack of information about the mechanisms behind the resistance of various tree species to elevated concentrations of heavy metals. The purpose of this work was to identify the relationship between the chemical composition of silver birch leaves (Betula pendula Roth) and the vital state of the tree stand in the pollution gradient caused by the Karabashmed JSC. For the study, natural stands of silver birch were chosen, located at different distances from the JSC Karabashmed in the northern and north-eastern directions. The content of macroelements (nitrogen, phosphorus, potassium, magnesium, calcium, sodium, sulphur; NPK was calculated as the total content of nitrogen, phosphorus and potassium) and microelements (cadmium, cobalt, chromium, copper, iron, nickel, lead and zinc). The dependence of the content of macro- and microelements in the leaves of silver birch on the vital state of the tree stand on the gradient of aerotechnogenic emissions from Karabashmed JSC was established. An increase in the concentration of sulphur and microelements (namely cadmium, lead, zinc, copper, iron and chromium) was recorded, as well as a decrease in the total content of nitrogen, phosphorus and potassium in birch leaves in the sample plots closest to the source of pollution. Correlation analysis revealed an increase in the content of cadmium, lead, copper, zinc and sulfur (correlation coefficients exceeding 0.3-0.6) and a decrease in the total content of nitrogen, phosphorus and potassium with an increase in defoliation, dechromation and deterioration of the vital state category.