No 3 (63) (2024)

Introduction. Qualimetry of the aboveground and belowground biomass of trees is an integral part of studies on the biological productivity and carbon deposition capacity of the forest cover, necessary for the correct assessment of the carbon cycle in the terrestrial biosphere in relation to climate change. Dry matter content (DMC) in phytomass fractions determines the specificity of the tree productional process, so an appropriate database is needed for its assessment in transcontinental gradients.

The availability of the first author's database on the qualimetry of forest-forming species of Northern Eurasia made it possible to formulate the purpose of the study, which was to study the regional features of DMC in the aboveground and belowground phytomass of Scots pine in Northern Eurasia.

Objects and methods. To achieve the purpose of the research, 3,700 DMC indicators of the aboveground phytomass and 89 DMC indicators of the root phytomass of Scots pine obtained on the territory of eight regions of Northern Eurasia were selected from the author's database of qualimetric indices of major Northern Eurasian species. On their basis, mixed-type regression models were built that included two types of independent variables: numerical variables taking values from a continuous series of numbers, and dummy variables representing discrete qualitative characteristics, in particular, the belonging of data to a certain species.

Results. Models of the dependence of DMC on the tree age and the stem diameter at breast height including a set of dummy variables have been built. The regression coefficients for numerical variables are significant at the probability level from p<0.001 to p<0.05, which means that the constructed models, differentiated by regions of Northern Eurasia, are characterized by a statistically significant contribution of tree age and stem diameter to the explanation of DMC variability in all phytomass fractions.

Conclusion. The ranking of regions by the DMC value in phytomass fractions revealed significant differences between them. These differences reach 10, 14, 22 and 14 % for DMC in stem wood, stem bark, needle-foliage and branches, respectively. Of the phytomass fractions, the greatest interregional difference (22 %) falls on the DMC in the needle-foliage, with a maximum in Western Siberia and a minimum in the center of the Russian Plain. The presented patterns of DMC changes in various phytomass fractions can be useful in estimating the absolutely dry phytomass and carbon deposition capacity of pine forests in different regions of Northern Eurasia.

Introduction. The forestry industry is one of the most controversial and conservative. On the one hand, the Russian Federation occupies one of the leading positions in terms of forest resources, while on the other, the share of the forest sector in the country's GDP does not amount to even one percent. This indicates the existence of problems hindering the development of the forest complex, which are observed at different levels of forest management and logging, from the allocation and taxation of cutting areas, the system of forest protection and conservation to the level of logistical, scientific and personnel support. Currently, among other problems, there is an increase in the volume of illegal logging and a lack of highly qualified personnel and technologies for work in forestry and the forest industry, which leads to violations of the boundaries of cutting areas and a lack of reliable data on them. Recently, the issues of the forest industry have been quite widely discussed at the higher levels of government in terms of strategic development planning. The Strategy for the Development of the Forest Complex until 2030, approved by the Government of the Russian Federation on February 11, 2021, involves a comprehensive modernization of the sphere, one of the main tasks of which is the digitalization of the industry.

The aim of the study is to develop a coupe demarcation technology using unmanned aerial vehicles (UAVs) as part of implementing the national project "Unmanned Aviation Systems" until 2030 and Order No. 608 of the Federal Forestry Agency (Rosleshoz) stipulating the need to provide regional forestries with machinery and equipment including UAVs necessary for forest patrolling, as well as within the framework of the Strategy for the sustainable development of the forest complex.

Object and methods. The object of the study is the method of coupe demarcation. The research employed analysis of data from open access sources, analysis of the regulatory framework governing the field of forestry, and comparison of research results.

Results. The authors have substantiated the efficiency of coupe demarcation using UAVs equipped with a system for dropping radiobeacons at points with known coordinates to mark the coupe boundaries. The paper presents calculations of the economic costs of using this system, calculations of the accuracy of radiobeacon delivery and the efficiency of using the new technology. The calculations indicate a reduction in labor costs on coupe demarcation in comparison with the conventional method.

Conclusion. The use of the proposed technology leads to a significant increase in the efficiency of the coupe demarcation process, reduces its labor intensity and improves the accuracy of marking the boundaries of areas designated for logging.

Introduction. Woody plants growing on the territories of industrial centers contribute to optimizing the state of the environment, perform environmental stabilizing and protective functions, and improve people's living conditions. The question that remains open concerns the seasonal dynamics of the content of photosynthetic pigments in the leaves of the silver birch (Betula pendula Roth), a species resistant to extreme natural anthropogenic factors.

Materials and methods. The Ufa Industrial Center (UIC) is a city with a population of more than 1 million people, where over 700 enterprises are located. The climate of the city of Ufa and its environs belongs to the temperate climate zone with a continental climate. The natural and climatic conditions of 2022 were characterized by multi-year averages. In 2022, according to the criteria of the Sanitary Rules and Norms 2.1.6.3492-21, the level of air pollution in the city of Ufa was categorized as “high”.

The purpose of the work is to determine the content of chlorophylls in birch leaves in the period from June to September on the UIC territory. The objectives of the study are as follows: (1) to determine the content of chlorophylls in the birch leaves during the growing season in the industrial and residential zones; (2) to determine the chlorophyll content in medium-leaved birch trees; (3) to determine the chlorophyll content in small-leaved birch trees.

The object of the study is the birch plantings in the UIC industrial and residential zones. In the lower part of the crowns of model trees, leaves were identified and numbered (10 leaves per tree). In order to ensure the representativeness of the experimental data, the chlorophyll content was determined in the interveinal space of each leaf at 12 points: six points on the adaxial side of the leaf (on the left and right halves of the leaf, on the tip, middle and at the base of the leaf) and six on the abaxial side (on the left and right halves of the leaf, on the tip, middle and at the base of the leaf). In June, July, August and September 2022 (every month at the same time, using the numbered leaves) the content of chlorophylls (a+b) in the birch leaves was measured using a Dualex Scientific+ device (‘Force-A’, France).

Results and discussion. In the period from June to September, the average value of chlorophyll content in the birch leaves in the industrial and residential-recreational zones was higher in September 2022. A comparison of chlorophyll contents in medium-leaved birch trees found that in the period from June to September the average leaf chlorophyll content is higher in the residential-recreational zone. When comparing chlorophyll contents of small-leaved birch trees, the average value of the leaf chlorophyll content during the period from June to September is higher in the industrial zone.

Conclusion. According to the obtained data on the seasonal dynamics of changes in the leaf chlorophylls content, it can be concluded that in conditions of environmental pollution, successful adaptive adjustment of the chlorophyll-protein complex of the assimilation apparatus of birch trees is observed. At the same time, the small-leaved form of birch is distinguished by higher variability of leaf chlorophyll content during the vegetation season in both residential and industrial zones, which is a manifestation of adaptive reactions to the growing conditions.

Introduction. Caring for young growth is the most important stage in forest cultivation, which ensures the productivity of forest stands. During the period from thinning to clearing, it is necessary to provide sufficient space for tree growth and take into account the competition between different species in the deciduous-coniferous forest. When using one kind and method of felling, it is possible to weaken or eliminate competition by means of various methods of influencing undesirable species, such as leaving stumps of the required height, de-topping, ring-barking of trunks, chemical destruction and pruning of tree crowns. Particular attention is paid to the ringing of trees subject to removal. Devices for tree ringing are considered, with their limitations indicated. Of great interest are the directions for improving and modernizing devices for tree ringing, providing for simple designs and high productivity by increasing the range of diameters of trees being ringed.

The purpose of the research is the engineering study of variants of mechanisms for tree ringing with consequent tree drying in the standing state.

Objects and methods. The objects of the study are designs of devices for ringbarking trees. The search method was used that involved conducting a review of existing tree ringing designs, their analysis, comparison, synthesis and specification with the identification of analogues and prototypes.

Results and discussion. Several designs for ringing trees to be removed have been proposed. Among them are spring, mobile and chain ringing devices. The designs of the devices and the principles of their use have been described in detail.

Conclusion. The developed mechanisms make it possible to expand the choice of design options for tree ringing devices. The novelty of the mechanisms presented in the article was confirmed by Russian patents. All the developed variants are characterized by the possibility of a wide variation of the diameter ranges of trees to be ringed, as well as by the mobility and simplicity of their designs. The use of the proposed mechanisms ensures lower fatigue of workers when ringing trees and moving between trees to be treated.

Introduction. Radioactive contamination of the environment due to the accident at the Chernobyl nuclear power plant led to restrictions on farming on a significant area in Russia, Belarus and Ukraine. Despite the fact that more than 30 years have passed since the accident, 16 thousand hectares of agricultural land in the Bryansk region are still categorized as lands excluded from use, and the problem of their rational use remains relevant.

The purpose of the study is to forecast the distribution of former agricultural lands across zones of radioactive contamination and soil groups, as well as predict the specific activity of ¹³⁷Cs in agricultural and forestry products grown in this area.

Objects and methods. A forecast assessment of the distribution of former agricultural lands across zones of radioactive contamination and soil groups over 30 years was carried out based on the analysis of information from the database containing the results of a radiological survey of former agricultural lands of the Bryansk region. The forecasting of ¹³⁷Cs content was performed with regard to several types of products of agriculture (winter rye grains, potato tubers, milk) and forestry (averaged mushroom basket, barked and unbarked wood of Scots pine and English oak) based on the coefficients of transfer (proportionality).

Results. It was found that in 2024 ∼46 % of former agricultural lands on sod-podzolic soils are characterized by a density of ¹³⁷Cs soil pollution from 555 to 1480 kBq/m². By 2055, 54 % of lands will move to the zone with a density of ¹³⁷Cs pollution of 185–555 kBq/m² and ∼16 % of lands – to the zone with that of 37–185 kBq/m². Winter rye grain compliаnt with the permissible standard for the content of ¹³⁷Cs can be obtained on an area of 2.3 thousand hectares in 2024 and 6.1 thousand hectares in 2055. Growing potatoes and obtaining feed for dairy cattle with an acceptable content of ¹³⁷Cs is possible on sod-podzolic sandy and sandy loam soils with a density of ¹³⁷Cs contamination <555 kBq/m² (3.8 thousand hectares), while on light and medium loamy soils – with a ¹³⁷Cs contamination density <1480 kBq/m² (5.7 thousand hectares). Forest mushrooms continue to be a critical food product in terms of ¹³⁷Cs concentrations. The standard for the content of this radionuclide can be exceeded at a pollution density of sod-podzolic sandy and sandy loam soils of 37 kBq/m², and on loamy soils – with a density of pollution of up to 185 kBq/m². One of the effective ways to use lands withdrawn from agricultural use is to transfer them to the forest fund for subsequent planting of forest crops or promoting natural reforestation.