编号 4 (2023)

In order to develop proposals for managing the functioning of the city’s green frame, a study has been carried out, regarding tree plantations and their litter layers, as well as some aspects of the urban ecosystems’ biological cycle of as part of the optimisation of the carbon footprint. The topic’s relevance is due to the global warming and the need to identify sources of direct and indirect anthropogenic impact on the carbon balance, as well as the need to assess the contribution of carbon emissions to the atmosphere of urban areas. The litter, despite its small contribution to the total carbon stock of the ecosystem, is the most mobile horizon, connecting vegetation and mineral soil horizons, thus its typology and properties are the most important characteristics that can be used to monitor urban ecosystems. It has been established that in urban ecosystems, compared to the natural analogues, there is an increase in the biological cycle intensity, which is associated with the following factors: a shift in the ratio of tree species in the city’s green frame towards a significant increase in the proportion of deciduous trees, the use of a greenery maintenance system and the destructive impact of recreation on litter layers. The percentage decrease in the amount of carbon in the litter of coniferous plantations as a result of recreational impact is 20–57%, in the case of the leaf litter collection – up to 90%, while in absolute terms the loss of carbon reserves is comparable and equal to 20–23 kg/100 m² (we note that that the litter variant of larch plantations shows the absolute values of carbon losses 3 times higher). All studied variants of urban greenery subject to pronounced anthropogenic impact, demonstrate a decrease in the biological cycle isolation compared to undisturbed ones. A change in the organic matter circulation direction in urban ecosystems towards its depositing as a part of terrestrial detritus can be implemented both by regulating the intensity of the greenery maintenance, and by reducing its loss during recreation – design solutions for the organisation of landscape objects with the diversion of visitors’ transit flows from the locations of conifers ecosystems.

Obtaining the experimental data on soil respiration is relevant due to significant range of CO₂ emission estimates in different ecosystems. The aim of work was to characterize CO₂ emission from soil surface of pine forests growing in different conditions on North-East of European part of Russia. The studies have been carried out in immature and mature pine forests Sphagnosa, Myrtillus and Lichen types located in the Institute of biology of the Komi Science Center, RAS forest stations. Carbon dioxide emission was measured using LI COR 8100 during the May-October periods in 2008–2017. A brief weather conditions characteristic was given. Higher values of the CO₂ flux from the soil surface was observed in July (1.9–2.9 g С m^–2 day^–1 in Sphagnosa type) and August (2.5–6.6 g С m^–2 day^–1 in Myrtillus and Lichen types). The year-to-year variability and influence of weather conditions on soil respiration were shown. The soil temperature had a close and positive relationship (R² = 0.49–0.77) with CO₂ emission whereas correlation with soil moisture was weak. During summertime the efflux of C-CO₂ in a pine forest of Myrtillus type was 188–442 g C m^–2, during the vegetation period (01.05–30.09) – 279–563 g C m^–2 and the snowless period (01.05–31.10) – 308–583 g C m^–2, which is 1.5–1.8 times higher than in the pine forests of Sphagnosa and Lichen types during the snowless period (р = 0.014) and growing season (р = 0.020). In summertime the losses of carbon were similar (р = 0.106). The pine forests of Sphagnosa and Lichen types were comparable in С-СО₂ efflux both during the vegetation and the snowless periods (p > 0.05). These data are important in assessing the expenditure part of the carbon balance in forest ecosystems in the European North-East of Russia.

Using the biophysics and visual assessment methods, a study on the vital state dynamics of the Pallas black pine (Pinus nigra subsp. pallasiana D. Don) trees damaged by fire was conducted. It is shown that a ground fire has a noticeable effect on the biophysical characteristics of the Pallas pine. In the post-fire period, there is a change in the electrical resistance of the tree trunk tissues, as well as an increase in its variation coefficient, which reflects the deterioration of their vital condition. The relationship between the parameters of the trunk tissues’ polarization coefficient and the level of the pine trees’ pyrogenic damage was revealed. The intensity of the needles yellowing reflects the amount of stress the trees experience during the pyrogenic impact, it is determined not only by the severity of the impact, but also by the protective response resulting in the mobilisation of the vitality reserves during the post-shock period. The negative effects of stress are manifested in a prolonged decline of the plants’ vital state. Differentiation of the Pallas black pine trees based on the types of response to the damaging impact was revealed. The individuals of an increased regenerative capacity ensure the group preservation under a strong short-term negative impact. Individuals with a weak response realise their advantage in a situation of a lingering stress, conservatively utilising their vitality reserves, which ensures the possibility of long-term survival under inhospitable conditions. Currently, the natural populations of Pallas black pine, are forming “scissors” of two evolutionarily different natural selection tendencies. Under the lingering stressful conditions, individuals with weaker reaction are more likely to survive and the elimination of individuals with a strong response to stress increases, which entails a decrease in the resistance of populations to a strong destructive effect.

In the flat regions of the North Caucasus, the cultivation of field crops is associated with the risk of causing destructive dust storms. A tried means of preventing them was the system of shelterbelts (SBs), created in the 50–70s of the past century. However, for a number of reasons and with age, they degraded into an unsatisfactory state. A need has arisen to carry out a complex of forestry activities aimed at improving and increasing the plantations functional durability. The purpose of the research was to determine the most rational ways and methods of these activities. The studies were carried out by employing the method of a comprehensive analysis of the SBs inventory materials obtained in 2007–2019 on a total area of more than 20 thousand ha^–1 using the current methodological standards as well as original approaches, with the participation and under the guidance of the article’s author. It has been established that on the chernozems, the SBs have been preserved almost across the entire original area, they possess a higher degree of biocenotic diversity and require individual economic activity regimes. The most common are the plantations possessing the windproof structures with sparse parent stands, dense layers of understorey and underbrush, as well as sparse single-storey stands with a highly developed ground cover and weakened tree vegetation. In the first type of plantations it’s prudent to carry out reconstructive fellings, aimed at the formation of a young seed or seedling-seed generation of the trees and increasing its wind permeability. The second one calls for sanitary fellings and agrotechnical maintenance, focused on stand’s renewal and thickening of the windbreak profile of these shelterbelts. On chestnut soil types, plantations of the 50–60s have disintegrated completely, while the plantations of the 70s have survived only in areas with increased moisture. They are in a severely weakened state and under a direct threat of dying. Possible recovery measures include sanitary felling and artificial reforestation along the entire course of the SBs, with the exception of the areas unfit for sustaining forests. Forestry activities should include long-term basic tillage, planting of pure 2–3-row plantations mainly from large and medium shrubs, species composition differentiation within the SBs in accordance with the quality of the soil.

For the cultivation of planting stock of forest-forming species, the measure most often used currently is the pre-sowing treatment of seeds with stimulants, which positively affects the germination of seeds and the growth of seedlings, and for each region of the country the choice of growth substances is different. The aim of the research was to identify the optimal stimulant and soaking time during the pre–sowing treatment of Scots pine seeds (Pinus sylvestris L.). The objects of research were one- and two-year-old seedlings, growing in the forest nursery of the Shaldai branch of the State Forest Natural Reserve (SFNR) “Ertis Ormany” in the Pavlodar region. Three stimulants (Baikal, Zircon, Humate-7 trace substances) and the fungicide Trichocine were tested. The field germination of seeds, the number of plants per unit area and the height of seedlings were all studied. In the experiment with a combined usage of the stimulants and the Trichocine, the average height of pine yearlings was lower than that of control seedlings. But at the age of two years, the average height of seedlings in the two experiments exceeded the height of control seedlings by 20.8 and 1.4%. Thus, the prolonged effect of pre-sowing seed treatment with the stimulants and the Trichocine on enhancing the growth and number of preserved seedlings per unit area at the age of two years has been proven. The data obtained from cluster and rank analyses showed that for the pre-sowing treatment of Scots pine seeds in the conditions of ribbon forests of the Irtysh region, the most optimal way was to soak the seeds in the Humate + 7 micronutrients for 12 hours together with the Trichocine (12 + 2 hours) in a concentration of 1.5 g of the stimulant and 0.6 g of the fungicide per 1 liter of water.

Important Forest Areas are core areas where natural complexes and their biodiversity are preserved. Forests in Orel Oblast are unevenly located. The forest cover is 8%. The following region’s districts, Dmitrovsky, Znamensky, Khotynetsky, and Mtsensky, are the most wooded ones with the forest cover making up 20 to 25%, whereas the lowest forest cover is found in the south-eastern districts Dolzhansky, Kolpnyansky, Livensky, and Pokrovsky, where this indicator barely exceeds 2.5%. The largest forest area has been preserved in the north-western part of the region under study. It belongs to the Orlovskoye Polesye National Park. Broad-leaved forests account for 19 243.42 ha (19.5%), and coniferous/broad-leaved forests account for 79,459.17 ha (80.5%). This study uses the route method, the method of geobotanical descriptions, and grid mapping. Having studied the Orel Oblast areas, we identified 34 Important Forest Areas with the highest diversity of rare and protected plants. There were 8 species listed in the Red Data Book of the Russian Federation, and 58 species listed in the Red Data Book of Orel Oblast.