The age of biological maturity is the age corresponding to the maximum value of the average annual growth of the forest stand. When the age of biological maturity is reached, the transition from the formation of a forest stand to its maturity takes place. At the same time, the maximum increase in the total biomass is observed and abundant fruiting begins. Empirical data on the current growth of pine and oak stands in terms of overall productivity were taken from A.Z. Shvidenko tables. As an analytical dependence of the biomass of forest stands on time, an ecophysiological model was used, which is explained from the point of view of non-equilibrium thermodynamics for open systems. Approximating the empirical values near the position of the maximum growth by a simple analytical dependence, we obtain the time at which the growth of the forest stand reaches its maximum value. On the other hand, the stand biomass is proportional to the growing stock with acceptable accuracy, especially in a fairly short period of time. In this case, the maximum increase can be determined by taking the second derivative of the function expressing the dependence of biomass on time and equating it to zero. Comparing the values obtained by these two alternative methods, one can judge the reliability of the results obtained and the quality of the tree-stand model used. The paper substantiates two alternative methods for determining the age of biological maturity of a forest stand. An important result for ecological and physiological modeling is the inclusion of the age of biological maturity in the FLR-model, since the maximum deviation of theoretical values from the corresponding empirical values is observed at small ages. In the future, it is planned to thermodynamically substantiate (or refute) the need to implement the process of ecological and physiological modeling of a stand starting from the age of biological maturity. There is reason to assume that the age of biological maturity determines the age from which it is possible to consider a dry ecological system.

The study is devoted to the identification of the early stages of damage to Norway spruce tree stands by a bark beetle. From a practical point of view, it is of crucial importance to identify the initial stage of bark beetle damage, in which colonized trees do not yet show distinct symptoms of damage, and the needles retain their green color. The objective of the paper was to study by methods of mathematical statistics changes in the vegetation indices NDVI and SWVI for Norway spruce stands, which in 3 years have gone from healthy to severely damaged. The objects of the study were 12 sites of mass reproduction of bark beetles and other stem pests formed in 2021 on the territory of Vyborg and Gatchina districts of the Leningrad region in mature Norway spruce tree stands. During the ground work, the survey and mapping of damaged sites were carried out. With the help of the EO Browser mapping service, Sentinel-2B satellite survey materials for June-September 2020 (no damage), 2021 (early stages of damage) and 2022 (late stages of damage) were received on the territory of the damaged sites. Vegetation indices NDVI and SWVI were calculated on the basis of the received remote sensing materials. With the help of variance analysis, a reliable and significant decrease in the values of both indices was established by the years of damage, as well as by years and months. It is noted that when bark beetles damage plantings, the seasonal dynamics of index values changes. Reliable linear trends of decreasing of both index values by year and month are revealed. Analysis of the sensitivity coefficients and synchronicity of changes in vegetation indices by year and month showed that the decrease in index values occurs independently of external (random) factors, as well as not synchronously relative to each other. In practical terms, the revealed patterns of changes in the vegetation indices NDVI and SWVI can serve as a signal about the initial stage of damage to plantings and the basis for conducting ground surveys with the aim of early detection of damage and timely prevention of their spread.

The article provides characteristics of the Botanical Garden named after. B.V. Grozdov and the history of its creation. The characteristics of the collection of the Botanical Garden are given, yes, but their distribution by geographical location and taxa. The features of the introduction and acclimatization of species in the garden are given. Recommendations are given on the selection of plants for introduction into green spaces in Bryansk.

The new data obtained by the authors expand and concretize the existing ideas about the typology and ecology of Siberian dwarf pine communities of the mainland areas of the Koryak district of the Kamchatka Territory. In the research area, the most widely distributed dwarf pine stands are shrubby-green-mossy, confined to the average conditions of moisture and soil richness. They should be classified as a Class II of natural fire hazard. Siberian dwarf pine stands rich with lichens occupy the poorest and driest habitats on gravelly scree of basalts and andesites. They are classified as a Class I of natural fire hazard. Cassiopeia dwarf pine stands are confined to drained lithozems on ultrabasic rocks, found on the upper border of the dwarf pine belt. According to the conditions of burnability, they are close to shrub-lichen dwarf pine shrubs and also correspond to the I class of natural fire danger. Dwarf pine stands rich with Sphagnum occupy the last step in the series of stagnant moisture. They are classified as Class IV, i. e. moderate natural fire hazard. Dwarf pine stands rich with cloudberry-sedge indicate the initial stages of the process of stagnant waterlogging and occupy an intermediate position in the ecological series between green-mossy and Sphagnum – rich forest types. According to the conditions of burnability, they correspond to Class III, i. e. average natural fire hazard. Dwarf pine stands rich with dwarf shrubs and reed grass are confined to habitats with flowing moisture. They are classified as Class IV, moderate natural fire hazard.

On the base of analysis of the best international practice, the influence of different technosphaeric components on birds is evaluated – such as urboecosystems, objects of recreation, marine port complexes and ferry, objects of oiland gas sector, objects of the infrastructure of renewable energy sources (wind mills etc.). The role of the birds in the system of monitoring of the technosphaere is evaluated. The necessity of the system approach is postulated, when the technosphaera is observed from the position of emergence, not like the simple totality of different objects, but principally new unity of the interactional components. Factors of positive and negative effects of the technosphaeric objects on the ornithofauna are revealed. It is shown that the anthropogenic effects on ornithofauna should be estimated as a complex, on the base of the system approach.

The article presents an assessment of the quality of one-, two- and three-year-old seedlings of norway spruce grown in open-ground nurseries of the Baltic-Belozersky taiga forest area. The relevance of the study is due to the identification of the quality of planting material under various growing conditions for the formation of a database that contributes to the development of programs for the targeted cultivation of seedlings. The research was carried out in 2022 in a temporary nursery with sandy loam soils, in permanent nurseries with medium loamy soils with full and incomplete technology of work. Incomplete technology of work consisted primarily in the absence of systematic weed control, loosening. Biologically active substances were used with the full technology of work. Surveys were carried out according to standard methods in the second half of the growing season. Temporary forest nurseries are characterized by a higher density of seedlings with a high proportion of healthy specimens compared to permanent nurseries. Seedlings grown in a permanent forest nursery with full technology of work and the use of biologically active substances have the best growth and the best quality indicators. The implementation of a complete technology of work with the use of biologically active substances in the cultivation of seedlings contributes not only to the early achievement of standard sizes, but also increases the resistance of seedlings to adverse factors. The success of seedlings can be assessed by the number of branches in the crown. A high dependence of the number of branches in the crown on the height of seedlings and the mass of roots was revealed. The lack of systematic weed control in a permanent open-ground forest nursery leads to a critical reduction in the density and proportion of healthy seedlings, a decrease in the biometric indicators of seedlings compared to a temporary nursery. Temporary forest nurseries on sandy loam soils with a minimum of technological techniques have shown high efficiency of growing spruce seedlings. It is necessary to pay attention to the method of growing seedlings in temporary nurseries, which was popular in the Soviet period.

The results of long-term tests of provenance trials planted under the program of VNIILM in 1977 in Leningrad region with seed progenies of Picea abies (L.) Karst., Picea obovata Ledeb. and hybrid forms of these two species are presented. During the 45-year period of crop development it was found that European spruce and hybrid forms with predominant features of European spruce have significant advantages over Siberian spruce in the test area. This is due to the influence of many factors. First of all, geographical origin of seeds and different degrees of plant adaptability to nonnative growing conditions. The best safety (46–54%), along with local Leningrad, is characterized by progeny of hybrid forms originating from Pryazhinsky leskhoz of the Republic of Karelia and Konoshsky leskhoz of the Arkhangelsk region. Low preservation (18–32%), extremely weakened condition and growth are noted in the progeny of P. obovata and hybrid forms originating from the most distant to the east (Komi, Sverdlovsk) and north (Arkhangelsk-Pinega) regions. For many years a reliable dependence has been traced: the more northern and eastern the location of maternal climatypes, the worse the condition, preservation, growth and productivity of progeny; the share of influence of geographical factors reaches, depending on latitude and longitude of origins, 48 and 64% respectively. Successful development of spruce offspring depends on factors of climate in places of seed production, the period with temperature over +5 °C having the maximal value; the share of its influence on growth of crops is 73–74%. At present, the leader in productivity is local Leningrad progeny. The best descendants of non-native climatic species were identified with origins within the borders: tentatively 61°40′ 54°20′N and 36°20′ 22°E; first of all this applies to origins from the Tver Region, Republic of Karelia (Pryazhinsky leskhoz), Republics of Lithuania and Belarus.

The article presents the results of field studies of indigenous and derived communities, similar in terms of the ecological space occupied by the regimes of salt richness of soils (Tr) and moisture (Hd) with the type of forest oak forest, boromum. Background species of forest stands are Quercus robur L., Tilia cordata Mill., Betula pendula Roth., Populus tremula L., Acer platanoides L.; undergrowth – Euonymus verrucosa Scop., Sorbus aucuparia L.; ground cover – Convallaria majalis L., Poa nemoralis L., Galium odoratum (L.) Scop. The ecological-coenotic spectra of plants of indigenous communities differ from derivatives in a smaller proportion of nemoral (Nm) species, somewhat larger in meadow-steppe (dry (MDr) and wet-meadow (MFr), as well as steppe (St) species). The oak part of the forest stands can be considered stable based on the H/G, S2 criteria and the dynamics of taxation characteristics, while the cenopopulation of Q. robur L. due to the same age of the trees and the absence of a constant generation turnover is unstable and degrading.

A study of the state of poplar plantations of balsamic Populus balsamifera L., which are in the stage of decay and assigned to logging in 2022, showed differences that arose during the full life cycle in fundamentally different growing conditions. Thus, in conditions of high anthropogenic load on the Novosibirsk Street and road network, the average diameter of the trunk at the base was 11.8 cm larger than that of the balsamic poplar, which grew in conditions of minimal anthropogenic load of urban forests of Novosibirsk. The maximum growth of balsamic poplar in urban forests is characterized by the first three decades of tree growth, then a gradual decrease in growth begins. The difference in growth over the first and last decades of tree life is 2.4 times. While for poplars growing on the Railway Line, the first two decades of tree growth are characterized by the maximum increase, then a gradual decrease in growth begins. The difference in growth over the first and last decades of tree life is only 27%. That is, the decrease in the volume of wood growth over time, especially in the last three decades of active development of urban road transport is not confirmed. While the decrease in the volume of growth in the conditions of competition in urban forests is becoming more noticeable every decade. Another important factor in assessing the condition of wood is its fautiness. In this case, all the negative environmental impact on the Railway line determined the formation and development of many defects of wood. Of the twenty-six specimens of balsamic poplar, 19 had wood cracks at the base of the trunk (73%). Three specimens (11%) had extensive hollows at the base of the trunk, probably obtained as a result of mechanized harvesting in winter. Five specimens (19%) had obvious signs of the presence of table rot with the destruction of wood. Plantings that grew in urban forests had fewer wood defects. These include the presence of cracks in seven copies of balsamic poplar (43%) and two copies at the time of demolition were dead wood of previous years. There were no signs of the presence of stem rot and hollows, frost-breaking cracks at the base of the trunks.

The forest management system should have the status of comprehensive felling, providing for the simultaneous implementation of elements for the harvesting of ripe and perestroika wood and felling of care (rarefaction) in the plantation. Complex logging should include the development of deciduous and deciduous-coniferous forests, when in one step the predominance of the spruce element in the stand with its high subsequent growth energy within the I–III classes of bonitet and resistance to forestdestroying factors is ensured. In order to form spruce trees from altitudinal undergrowth up to 4 m (average – up to 1,5–2,0 m) with ensuring the productivity of the stand according to class I-II of the current bonitet, it is sufficient to preserve the undergrowth within 1,5–3,0 thousand copies/ha. This approach allows for better quality Subsequent rarefactions at an early stage with a selective selection method will contribute to the cultivation of spruce trees from trees of all categories (undergrowth, self-seeding) with the best hereditary properties, excluding their oppression. Such a method of complex logging will make it possible to form valuable spruce plantings during logging on a selective basis for the breed and quality composition of the spruce element. Complex logging is not considered in the current Russian legislation, which is due to the lack of sufficient scientific justification and regulatory support. Long-term research at a stationary facility allowed us to follow the formation of plantings after complex logging and develop scientifically based criteria for their implementation.

The problems associated with forest fires are significantly aggravated against the background of climate change. At the same time, the organization of forest protection from fires is one of the most expensive forestry measures, which requires optimizing the costs of forest protection by linking the volume of activities carried out with forest fire risks, in particular, with the indicator of fire danger in forests, depending on weather conditions. At the same time, the methods currently used to determine this indicator do not take into account the natural and climatic characteristics of the country's regions, which led to the need for the specialists of the FBU VNIILM to develop a new classification of fire hazard in forests depending on weather conditions. The accumulation of large volumes of structured data in the field of forest protection from fires, as well as the development of information technologies, make it possible to optimize existing approaches to determining the boundary values of a complex indicator of fire danger in forests according to weather conditions and to perform detailed calculations for all regions of the Russian Federation for the first time. In order to scientifically substantiate the feasibility of implementing the developed classification, a method (including calculation formulas and an algorithm) is proposed, which is based on a comparison of the amount of costs for aerial forest patrolling (calculated according to the regulated number of flights with the corresponding fire hazard class) and the costs of untimely detected fires that have moved into the category of large (only those that could arise on days when flights were not planned according to the current scale, but should be carried out according to the new one). To perform calculations, a special set of software scripts in the PostgreSQL language was developed. On the basis of archival data of the Remote Monitoring Information System of the Federal Forestry Agency (ISDM-Rosleskhoz) and data from regional dispatching services, an assessment of the economic consequences of the transition to a new classification was made. Calculations have shown that despite the fact that the proposed method does not take into account the entire possible effect, it shows the economic feasibility of updating the classification of fire danger in forests depending on weather conditions. The proposed method can be used to prepare a scientific justification for improving the classification of forest fire hazard by weather conditions. In addition, the developed algorithms will be used in the management decision support system in the field of forest fire protection when assessing forest fire risks and planning forest fire events.

So far enviromnemtal technogenic contaminatioin including heavy metal emissions was one of reasons of forest decline and mortality while its conservation is a priority target of forestry. This paper goal was an experimental study of pine ecosystem component responses on controlled heavy metal fallout impacts (zink example) to substantiate allowable element load levels for Scotch pine woods. 3 stationary sample plots (respectively in 15 year old, middle aged and mature stands) in pine green moss woods with background indicators of contaminatrion level, stand state and inventory characteristics, regeneration pattern, grass and soil cover were established. Zink as a nitric acid zink salt (Zn(NO₃)₂·6Н₂О) was introduced manually by dispersion over soil in the plots according to the element loads: 1) control (0 g/м²), 2) 7 g/м²; 3) 30 g/м²; 4) 90 g/м²; 5) 150 g/м²; 6) 225 g/м²; 7) 300 g/м; 8) 600 g/м² (in middle aged and mature stands). The study resulted in development of a technology to define allowable heavy metal impacts on forest stands based on field experiments that raises environmental rating credibility sufficiently. Minimum calculated values are referred as utmost allowable fallout (load) values since they are characterize start-up of structural-functional changes in forest stand. According to the studied indicators utmost allowable zink fallout values for pine phytocenosises are as follows: self seeding conservation – 4 g/м2 (40 kg/ha), number of pine self seeding 7 g/м² (70 kg/ha), number of pine germinations – 9 g/м² (90 kg/ha), moss dedeechromation – 17 g/м² (170 kg/ha), neddle dechromation = number of missing grass cover species – 22 g/м² (220 kg/ha), annual height growth –14 g/м² (140 kg/ha), stand state index – 42 g/м2 (420 kg/ha), кг/га), tree mortality – 54 g/м² (540 kg/ha), needle length – 62 g/м² (620 kg/ha). Utmost allowable zink fallout (loads) values for various pine phytocenosis components in green moss forest types of softwood and hardwood forest zone were offered for th 1st time that will sufficiently raise forest dynamics prediction in areas impacted by industrial plants.

Forecast calculations of the use and reproduction of forests, implemented in the form of various, most probable and promising scenarios, are necessary for strategic planning of forestry sector development at the regional level. In this study, scientifically based parameters of forest use volume for the long term, comparable to the felling turnover in coniferous stands in the forests of the Arkhangelsk region, were obtained. The paper presents an analysis of scenarios modeling for the Arkhangelsk region forests using the model developed by scientists from the Northern Research Institute of Forestry (author N.P. Chuprov), classical options for calculating allowable cutting volumes carried out during performing forest inventory. The results of the study show the possibility of maintaining a consistently high level of forest use, taking into account the species change and the implementation of forestry measures complex. For the forest management units of the south part of the Arkhangelsk region, the predicted amount of forest use is lower than the officially accepted volumes, for the forestry’s of the northern part, there is an excess of the allowable cutting volume, for the central part it practically coincides. The implementation of an intensive model for the use and reproduction of forests in the region is one of the indicators of the likely application of one of the optimal multivariate forecast scenarios.

The article discusses the development of a practical laboratory protocol for creating DNA libraries for high-throughput genotyping of Karelian birch. Karelian birch wood (Betula pendula Roth var. carelica (Mercklin) Hämet-Ahti) has always been valued for its unique and distinctly patterned annual rings. This material is highly prized in manufacturing and is used in furniture, tableware, various interior items, and decorative inlays. Due to the complexity of identifying the type of wood at the early stages of tree growth, plantations with a large number of individuals have to be used. The process of selecting «Karelian» samples based on the external characteristics of the tree is challenging because it largely depends on the knowledge and experience of a breeding specialist. Making the selection of «Karelian» forms more precise and faster can be achieved with genetic markers that objectively reflect changes in the genome associated with the formation of patterned wood. Identifying the genetic loci that determine the «wood patterning» trait in seedlings at early stages of development would help in the future to create «pure» Karelian birch plantations without the presence of trees with regular wood. Genetic markers allow for a more precise selection of «Karelian» forms, excluding trees with regular wood. To develop such molecular markers, it is necessary to identify mutations in Karelian birch genes that distinguish it from pendulous birch and are linked to the inheritance of «patterned» wood. The technology of high-throughput genotyping based on sequencing (Genotyping By Sequencing, GBS) can be used to search for mutations. One of the GBS variants is the technology of reading short DNA sequences adjacent to specific restriction sites (RADseq, Restriction site-associated DNA sequencing). The development of a working laboratory protocol for creating RADseq libraries is a key step in high-throughput genotyping projects. The goal of this research is to describe the protocol for preparing a RADseq library using 12 Karelian birch DNA samples, as well as to analyze the quality of the obtained DNA fragment readings from the sequencing of the created library using the Illumina HiSeq2500 instrument. The results of the analysis showed that the protocol used allows for obtaining high-quality libraries from birch leaf DNA. This enables the progression to the next stages of analysis, including aligning reads to the reference sequence and searching for SNP markers.

The results of the analysis of the assortment of cultivated and wild groundcover plants growing in the conditions of the city of Bryansk, promising for use on objects of landscape architecture and in decorative gardening, are presented. The studies were conducted in the period from 2021 to 2023. In the conditions of Bryansk, 24 species of cultivated and wild-growing groundcover herbaceous plants are used, which are part of 13 families and 19 genera. The largest number of groundcover plants is represented by the families of thick–leaved (Crassulaceae) – 6 species (25% of all plants) and Clearleaved (Lamiaceae) – 5 species (21%). Two types of groundcover plants were found in the Cabbage (Brassicaceae) and Primrose (Primulaceae) families (9% of the total number of groundcover species each). In the conditions of the Bryansk region, the species of European origin have the largest representation (33% of all plants). These include: Alpine arabis, young roofing, acrid ochitok, monetted verbena, small periwinkle, creeping gum, yellow green, mottled clear, creeping thyme and European hoof. According to the color of flowers in the studied groundcover species, we identified plants with white (24.8%), golden yellow (20.2%), lilac (13.8%), pink and purple (9.5% each), cream, blue and nondescript (5.7% each) and purple (4.3%) coloring. According to the color of the leaves of the studied groundcover plants, we identified plants with light green (33%), dark green (24%), mottled (19%), purple (10%), blue (9%) and silver (5%) coloring.

The mosaic nature of the components in the forest biogeocenosis is expressed in biogeocenotic parcels. The parcel structure of the phytocenosis allows a more detailed assessment of the presence, species diversity, nature of the distribution of plants over the area and the prospect of natural renewal. The dynamics of the parcel structure of forest phytocenoses (biogeocenoses) over time after anthropogenic impact on them is poorly understood. The purpose of the study is to analyze the parcel structure of forest biogeocenosis and its dynamics after selective sanitary felling. The study area belongs to the mixed forest zone, a forest-growing area of pine forests on the left bank of the river Desna and is part of the Bryansk forest massif. The climate of the study area is temperate continental, characterized by an average annual air temperature of + 4.9 ºС, and an average annual precipitation of 700 mm. The object of research is a spruce-pine plantation, which, as a result of selective sanitary felling, has been reorganized into a pine hazel-hoof type forest. Isolation of plant parcels in the studied planting was carried out according to the method of N.V. Dylis, accounting of plant components – according to generally accepted methods. An increase in the number of parcels was noted in the first years after logging, which leads to the need to group them for economic purposes. Four years after logging, species typical of open areas change to forest shade-tolerant species, their occurrence and projective cover increase. The spatial structure of parcels has also changed. The bream-new-maple-linden parcel predominates (46%), maple-linden occupies 28% of the area, linden – 24%, and raspberry occupies the smallest area – 2%. On the technological corridors of the cutting area, the grass vegetation is replaced by trees, shrubs and forest herbaceous species. In places where logging residues were burned, trees, shrubs and herbaceous vegetation also expanded. The use of the parcel structure of phytocenoses, the patterns of its development and the management of this process in selective cutting areas will allow a rational approach to the process of forming productive, optimal forest phytocenoses in the forest park zone.

The current study aims at assessing the risk of transforming the genetic structure and reducing the genetic diversity when the size of the selected population due to the selection of plus tree clones for phenotypic characteristics decrease. From 8 to 16 best clones were sorted out for different areas of selection having analyzed the phenotypic characteristics. The selection intensity was between 6.3–29.9%, while the selection differential was between 108.1–256.6%. Changes in the genetic parameters of selected populations were analyzed with the use of two types of DNA marker, namely nSSR and ISSR. We traced a substantive change in the frequency occurrence of ISSR markers in the groups of selected clones compared with the original sample. The allele frequencies of nSSR markers remained the same. The main threat of reducing the size of the selected population is the loss of allelic diversity in the case of nSSR markers (15.6–31.3%) and the number of PCR fragments in ISSR markers (11.8–19.9%). Other indicators of genetic diversity, such as effective allele number, heterozygosity, and inbreeding coefficient, have minor dependence on the size of the selected population. The number of effective alleles for nSSR markers varied in different groups of selected clones within 2.97–3.77 at an initial value of 3.47, the inbreeding coefficient was within 0.460–0.480 at an initial value of 0.503, and the expected heterozygosity was in the range of 0.325– 0.375 at an initial value of 0.355. We can observe a slight decrease in the number of effective alleles for ISSR markers, due to single selection from 1.31 to 1.28–1.29, and the expected heterozygosity from 0.205 to 0.175–0.193. To enable the monitoring of the genetic transformation of selected populations, we consider it feasible to carry out genetic certification of all selected plus trees. Furthermore, it is necessary to involve as many plus trees as possible in the breeding process while enabling the selection at the next stage of breeding without a crucial loss of genetic diversity.

The paper presents data on the study of such indicators of soil fertility as the content of organic matter and mobile forms of phosphorus at different stages of revegetation of former arable soils in the Leningrad region (Russia). After the removal of agricultural load, post-agricultural plant communities, which play a role in the soil formation process, were formed on these lands. The investigated sites are located on two-membered soils within the Gatchina district. The agrochemical condition of the soil complex under a series of sites at early successional stages at 5, 10, 20 and 25 years after stopping use for arable land, as well as on old fallow soils of 85 years with different composition of tree species participation was analysed. Plots with different dominant species of tree and shrub vegetation were also identified on sites fallow for 25 years. Statistical analysis of the obtained data showed that with increasing period of soil fallow the average indicators of soil organic matter slowly increase and level out by 2025 years, but by 85 years they slightly decrease. The dynamics of mobile phosphorus forms is significantly affected by heterogeneously regenerating woody-shrub vegetation closer to 2025 years. At the abandonment period of 25 years, the influence of the main tree and shrub species on soil fertility indicators is not traceable. Influence of coniferous stand composition as an environment-forming factor on soils depends on the share of spruce and pine. At the last considered stages of succession of former old fallow soils organic carbon accumulation is mainly due to living ground cover characteristic for forest, as well as coniferous and woody debris.

Currently, there is no consensus among researchers regarding the optimal growing conditions that contribute to the formation of pine wood of «optimal quality». The data published in the literature allow us to conclude that the variation of volume and strength characteristics of pine wood is within a narrow range, within low or medium levels of variability. The aim of the study was to identify the relationship between strength characteristics and macrostructure parameters of annual growth of pine wood, as well as to model the dependence of strength characteristics on pine wood structure parameters and density for the study region. The research of pine plantations covered the region of the northern part of the Russian Plain. All necessary measurements and calculations were carried out on the sample plots in accordance with the methods and standards in the field of forest taxation. Data processing was performed using standard or modified methods and software equipment. To determine whether there is a relationship between strength characteristics and individual linear parameters of tracheids of the early and late zone of the annual ring of pine wood, modelling was carried out using statistical methods. For a more detailed and complex analysis, multiple linear and non-linear regression was constructed with the assessment of the significance of the influence of the factors of microstructure of the annual ring by means of t- and F-tests using a specialised statistical analysis and forecasting package ALGLIB. The evaluation shows that the variability of the resistance of pine wood to compression along the fibres in the stands of the European North-East of the parameters of the structural elements of the annual ring is best explained by variations in the radial diameter of earlywood tracheids and the proportion of the early zone in the annual ring. The results of the study suggest that forest management measures aimed at «optimizing» the annual growth in diameter do not allow us to expect an improvement in the physical and mechanical properties of common pine wood in plantations of the European North-East of Russia. The confidence interval of changes in strength characteristics does not extend beyond the values of 35–50 MPa. The presence of a connection between the resistance of pine wood to compression along the fibres is explained by 50% of the sum of all influencing factors by structural components of radial growth. Modelling using statistical methods was carried out to determine whether there was a relationship between strength characteristics and individual linear parameters of the tracheids of the early and late zones of the annual ring of pine wood.

The study aims on development of the approach to classification of forestry machines basing on machine learning methods, which use data clustering and logistic-regression classifier. The study uses information on characteristics of 39 models of eight-wheeled forwarders manufactured by Ponsse, Rottne, Komatsu, John Deere, HSM, Ecolog. The data was obtained from the official websites of the manufacturers and is current for 2023. The data processing was performed on Jupyter Notebook platform. In computational experiments, the classifier model based on logistic regression was able to classify forwarders’ models to one of the four classes corresponding to the cluster labels obtained with k-means algorithm, given the information on 14 passport parameters of the machines, with accuracy at level of 92– 94%. The classifier model, which used as the parameters 1–2 of the principal components of the features matrix, was able to classify the considered forwarder models into 3 classes with accuracy of 97–98%. The accuracy of the model when classifying into 4 classes was lower with estimate at level of 90–94%. Meanwhile, results of the computational experiment showed that logistic regression models when classifying the forwarders into more than 5 classes bear significant loss of the accuracy. The computations results stayed stable during cross-validation with a high assessment of the accuracy. The prospect of further research lays in testing the classifiers on a generated data to assess the sensitivity of the logistic models to the parameters’ changes, and development of a method for obtaining an adequate estimate of missing feature values.

The article develops the dynamic loading of the power plant of a feller buncher machine, equipped with a feller head with a disk saw, during the acceleration of the saw blade. A mathematical model has been developed that allows, at the design stage of a compact feller buncher machine, to determine the magnitude of a significant dynamic moment existing on the machine’s power plant. The mathematical description is in the form of the Lagrange equation of the second kind. An example of calculating a mathematical model for a LP-19F feller buncher machine equipped with an FMG-Timberjack feller head with a disk saw is given. The presented graph of changes in the additional dynamic moment at system acceleration times of 0.3, 0.5 and 0.8 s. Analysis of the research results showed that the amount of additional dynamic moment in the saw blade acceleration modes is insignificant. With an acceleration time of 0.3 s, the maximum value of the additional dynamic moment is only 7.6 N·m.

The article deals with the issues of longitudinal sawing of round timber. The aim of the research was to develop a band saw with a simplified design, with reduced metal consumption and increased mobility. The development of a new technical solution in the field of designs of band saws, not tied to a specific one workshop, but capable of sawing in different places, including cutting areas, was implemented. The article gives a detailed description of the design of the new woodworking machine and the sequence of its work when delivered to the logging site for sawing round timber. The power unit transmits torque through the driveshaft of the vehicle, the tapered gearbox, the belt gear and the bearing assembly to the stepped pulley formed by the automobile rubber tires of two different diameters that drive the band saw. The proposed design of the device of the band saw for longitudinal sawing of round timber allows to simplify the design of the machine, reduce its dimensions and makes it possible to produce longitudinal sawing away from the woodworking enterprise, increasing the mobility of the technological process. The resulting unedged lumber can be immediately transported to the consumer, which reduces the cost of production transportation of raw materials and storage of finished products.

The article describes a methodology for studying the thermal and moisture properties of soils by complex methods that allow determining both thermal characteristics and moisture properties of soils on the basis of testing a single sample. The presented technique is implemented with the help of a specially developed installation for the complex determination of thermal and moisture properties of soils. As a result, the values of the coefficients of thermal conductivity, thermal conductivity and specific heat capacity for loams, sandy loams were obtained, and the effect of density and humidity on their magnitude was investigated. The fuel assemblies of soils at various humidities and compaction coefficients were studied. The main thermophysical characteristics and humidity properties of heavy loams for various humidities and densities are determined. Statistical processing of measurements was carried out in order to determine the relative error and the required number of measurements.

The study is devoted to the analysis of the performance of a wheel-type logging machine with a gripping-cutting device installed on it when performing technological operations for the removal of a cut tree from a cutting area to the place of packing on a portage by the machine. The paper proposes an information-logical model of the technology of operation of a logging machine and a mathematical model for determining the time for performing technological operations for the removal of a cut tree in a vertical position by the course of a logging machine. A detailed analysis of the components of the technological process of the logging machine was carried out. On the basis of the mathematical model, the time components of the shift productivity of a logging machine with a vertical removal of a cut tree were determined. A formula is proposed for calculating the productivity of a logging machine, taking into account the sequence and frequency of operations. As a result of the work, the dependences of productivity on the length of the path from the portage to the tree were revealed at different speeds of the machine when removing a vertical tree for different apiary widths. It has been established that the cycle time for processing one tree at the minimum values of the parameter variation range is 165 s, of which 90% of the time is spent on moving operations. At the same time, the minimum theoretical shift productivity of a logging machine with an average volume of one tree of 0.1 m3 is 13.64 m3/cm. The simulation results show that increasing the length from 15 m to 30 m reduces productivity by only 1-5%, but doubling the travel speed increases productivity by 50%.

Wood is an anisotropic material, as a result its physical and mechanical properties are different in the longitudinal and transverse directions. The variation in the wood properties is characteristic within the same species and in the tree trunk. Shrinkage is an important technological wood property that characterizes the change in the linear dimensions and volume of wood with a change in the amount of bound moisture. The value of wood shrinkage is uneven in the longitudinal and transverse directions and largely depends on the species and density variability in the tree trunk. The shrinkage value is necessary for the rational use of wood, its accounting and the choice of processing technology. The aim of the study is to establish the shrinkage variability of pine wood in a tree trunk with forest stands in the forest-steppe zone of the Voronezh region. The studies were carried out on sections of wood sawn at different trunk heights. It has been established that the value of volumetric shrinkage along the trunk height decreases from the butt to the top by an average of 1.2% per meter. The variability of wood shrinkage in the tree trunk in the tangential direction is greater in the central and middle parts of the trunk radius, in the radial direction in the peripheral and middle parts of the radius.

The technological process in woodworking associated with the deformation of the processing of soft hardwood is progressive. Several specific tasks have been carried out to determine this. By modeling the physical processes of deformation in soft deciduous wood, certain features and conditions are taken into account, which is most fully reflected by mathematical models. Through this tool, a list of rational modes is proposed for cutting as a result of analytical processing of the contact interaction of the tool with wood in a specialized computer environment. The most productive of the technological operations were named, and technological maps were prepared, where each basic deforming treatment of soft-deciduous wood for mechanically processed wood is prescribed. With the revision of the research methodology, a new perspective for the application of the listed technological processes was determined – economical and ergonomic. With the help of subsequent analysis, the progressiveness of new developments was determined, which make it possible to carry out deformation of the processing of soft deciduous wood as efficiently as possible.

Currently, the issue of creating protective materials that prevent the effects of ionizing radiation on biological objects – neutron fluxes, is relevant, since the supply of well-known foreign neutron-protective materials to the Russian Federation has been discontinued due to the imposition of sanctions. Wood is a hydrogen-containing material, and the hydrogen content in a unit of its volume is not less than in a unit of volume of traditionally used protective materials. It is important from a scientific point of view to consider the nature of changes in ionizing radiation, in particular, neutron fluxes, when meeting with wood protection. The paper provides a theoretical justification of the possibility of using wood as a neutron-protective material. The process of elastic neutron scattering on atomic nuclei of matter is considered, since the dominant part of the energy transferred to biological objects and, in particular, wood, is due to the elastic scattering of fast neutrons on the nuclei of H, C and O. When determining the energy that a neutron loses as a result of elastic scattering in wood, the classical laws of conservation of energy and momentum are applied. The research methodology is based on the analysis of the neutron energy reduction process when interacting with nuclei of hydrogen–containing substances, including wood, both natural and modified by compaction. It is proved that wood is a neutron moderator material. The use of modifying wood processing or its compaction is effective, while the protective properties are not inferior to such well-known and widely used materials as water, polyethylene, polystyrene. The field of application of wood as a protective material is much wider than the known protections due to its high structural properties, accessibility and cheapness.

The possibility of modification of mineral filler-calcium carbonate by nonofiber cellulose is shown. Bacterial cellulose synthesized by bacterial strain Komagataeibacter rhaeticus CALU-1629 in the amount of 1–5% to the mass of a.s. fiber was used as nanofiber cellulose. It is established that modification of the filler with bacterial cellulose allows to obtain paper with the content of filler up to 50% providing its retention in the paper by 95–98% without the use of retaining agents. Modification of the filler with bacterial cellulose allows to increase the mechanical strength of paper with filler and reduce the absorbency of paper, which will make it possible to significantly reduce the use of cationic starch and bonding agents in paper production.