The winter hardiness of common hazel was assessed in late March – early April, when a more stable temperature regime was observed, and after the end and return of late spring frosts. Another important indicator in assessing the prospects of using plants in landscape architecture is the drought resistance indicator. The effect of drought affects the water metabolism of plants. A large loss of water due to intensive transpiration causes the development of water deficiency in the plant, which can lead to death. In the conditions of Bryansk, all the studied hazel plants and its form 'Purpurea' have high winter hardiness and good drought resistance, which means that they are promising for their use in landscape architecture. However, in individual specimens of the species hazel growing in open areas, burning of their edges may be observed on the leaves during the dry period. A monthly assessment of the decorative value of common hazel and hazel 'Purpurea' was carried out according to the method of O.Y. Yemelyanova «Scale of gradations of signs for a comprehensive assessment of the decorative value of woody plants during the year». The sum of the points for the year shows the degree of decorative effect of the plant in the design of the urban and park environment. Both species are assigned to highly decorative shrubs.

A 2021–2022 study investigated the relationship between forest stands and pests and pathogens in coniferous forests in the north-west of Europe, Russia. The study involved 157 observation plots (PPUs) in mature and overmature forest stands, predominantly spruce or pine. The condition of spruce stands varies insignificantly as one moves north, while pine stands deteriorate somewhat. Four PPUs were excluded due to a sharp deterioration caused by an outbreak of the European bark beetle. The data showed no connection between average condition and pests and pathogens, except for spruce canker, the most common disease in the studied regions. A positive correlation was found between spruce stand condition and this disease. In pine forests, necrosiscanker diseases and crown openness predominated. The pine conk Porodaedalea pini was found sporadically in all PPU groups, with the exception of the Murmansk region. Armillaria spp. and species and groups of bark beetles and wood borer pests typical of northern taiga European forests were found in all PPU groups. Heat supply's influence on tree stand condition is not a leading factor, but can indirectly increase pest activity. In the absence of mass reproduction and disease development, pathogens and pests do not significantly impact tree stand condition, except for canker.

The landscape organization of the territory of sports facilities in the city of Arkhangelsk is considered. The purpose of the research is to check the landscape organization of the territory of sports facilities in the city of Arkhangelsk for compliance with regulatory documents and propose measures to improve it. The objects of research were sports complexes: «Trud», «Dynamo», «Burevestnik», «Volna», as well as the A.F. Lichutin sports complex and the V.S. Kuzin ski stadium. These facilities differ in size, condition of sports fields, playgrounds and tracks, availability of necessary equipment and special equipment, and remoteness from the city center. Sports complexes are located in the European North, which is characterized by harsh climatic conditions with long winters, relatively cool and rainy summers. These conditions undoubtedly affect the urban flora assortment (as a result, it is rather poor). During the study of green spaces on the territory of sports complexes, the following types of assessment were carried out: dendrological, bioecological and aesthetic (landscape and architectural). The dendroflora of plantings on the territory of the surveyed sports complexes does not differ in species diversity and is represented by 11 species of trees and shrubs. Moreover, 8 breeds are indigenous, and 3 are introduced. We have found that landscaping of sports complexes in Arkhangelsk is not given due attention. The plantings have low decorative value (on average 2-3 points) and satisfactory condition (49%). In terms of the number of trees and shrubs and their quality, green spaces do not meet regulatory requirements. Using the example of the Burevestnik stadium, recommendations on the landscape organization of the territory, taking into account the requirements for tree and shrub vegetation, are proposed. The creation of a favorable microclimatic regime on sports grounds, biological and psychological comfort for athletes increases their performance, lengthens the season of comfortable conditions for sports.

The article considers the technology of assessing the quality of forest taxation materials based on the analysis of the relationship between the taxation indicators of plantations and their spectral-reflective characteristics. The research uses Sentinel-2 satellite imagery data in the visible and infrared spectral ranges with a spatial resolution of 10 m.

Forest seed plantations of Scots pine (Pinus sylvestris L.) in the Orekhovo-Zuevsky forestry of the Moscow region are one of the most important objects for obtaining seeds of this species with improved hereditary properties and preserving the genetic fund of highly productive plantings in Russia. For the first time for this object, the sanitary condition of cultivated plants was studied and the species list of pathogenic micromycetes developing on dying shoots, needles, branches and cones was established. Data were obtained for the observation period from 2017 to 2023. According to the results of the study, 19 species of micromycetes were identified, the most widespread are the causative agents of shoot blight and needle cast: Gremmeniella abietina (Scleroderris canker), Sphaeropsis sapinea (Diplodia shoot blight), Sclerophoma pithya (Sclerophoma shoot blight) and Thyronectria cucurbitula (Thyronectria shoot blight), as well as the causative agents of needle cast – Dothistroma septosporum (Dothistroma needle blight or red band needle cast) and Cyclaneusma minus (Cyclaneusma needle cast). The identified species are new for the surveyed forest seed plantations and insufficiently studied in the Moscow region. T. cucurbitula have not previously been reported in the region. As a result of complex development of these species, there is a decline in sanitary condition, shoot blight in the lower and the middle parts of the crown, the loss of cones and a decrease in seed yield. Severe damage to pine undergrowth was revealed in adjacent natural plantations and on annulled forest seed plantations. On young plants, the development of shoot canker, as well as Diplodia shoot blight, Thyronectria shoot blight and Dothistroma needle blight, leading to the death of tops, shoots, and, less often, entire plants, was noted. Along with pine, among the plants affected by S. sapinea in the adjacent areas common juniper (Juniperus communis L.) in undergrowth was noted. The occurrence of pathogens of these diseases in adjacent plantings contributes to a high risk of their further spread on pines of the forest seed plantation.

Due to the process of restoration of natural vegetation cover on post-agrogenic territories, changes occur in the ecological functions of soil and in the soil formation process, which in turn lead to evolutionary changes in the entire soil complex. The paper considers the relationship between the early stages of tree and shrub vegetationregeneration on fallow lands and the agrochemical state of the soil complex under them. The objects are united by similar soil and ground conditions, located in Leningrad region, Russia. The series of experiments had time periods of stopping use under arable land at 5, 10 and 25 years. Vegetation taxation was carried out and soil samples were collected with following agrochemical analyses. Experimental plots were also plotted to detect microbiological activity and soil respiration. The results of the study showed that on the experimental sites soils regardless of the fallow period are characterized by acidic reaction of the environment (medium and strongly acidic). With the increase of fallow period on the studied plots there is a decrease in the content of mobile phosphorus (on plots with fallow period of 5 and 10 years the content is high, and on plots with fallow period of 25 years it is low). With the increase of fallow period there is a decrease in the number of correlations between agrochemical soil indicators, but the share of statistically reliable relationships increases, indicating stabilization of natural processes occurring in the soil complex, which were disturbed by regular plowing. In the process of restoration succession on post-agrogenic territories changes in the process of humus accumulation occur - the direction of the process changes from increase of humus with increase of pH value on the plot with fallow land of 5 years, to decrease of humus with increase of pH value on the plot with fallow land of 25 years. The activity of soil micromycetes decreases with increasing fallow period and the influence of soil bacteria increases. The processes occurring in the soil complex on lands withdrawn from active agricultural use require additional close study in order to develop further recommendations for their management.

One of the potential threats to coniferous forests of the Russian Federation is the spread of pine wilt disease caused by the pinewood nematode Bursaphelenchus xylophilus. This quarantine organism has not yet been detected in Russia, but is widespread in neighbouring countries: China, Japan, South Korea. In natural pine plantations the spreading of B. xylophilus is carried out by Monochamus beetles, but stressed trees are also infeсted by other insects, in particular by bark beetles of the genus Ips. The results of studies conducted under controlled laboratory conditions on the possibility of transfer of B. xylophilus nematodes by the bark beetle Ips acuminatus are presented. For this purpose, two types of pine (Pinus sylvestris) logs with I. acumunatus (type I) and artificially infested with B. xylophilus (type II) were placed together in one cage. I. acuminatus beetles were found in nematode-infested pine logs, and after 25 days, 47% of the emerging beetles in the infested wood contained the B. xylophilus juveniles. The nematodes B. paraburgeri, B. doui, Teratorhabditis synpapillata, Micoletzkya synpapillata were also found in I. acuminatus beetles and wood. The nematodes were identified using molecular genetic diagnostic methods. The highest number of nematodes in beetles (91%) was found in the mid-thoracic section of bark beetles under the elytra. No nematodes were found in the beetles during water flushing from the beetle surface. The results suggest that the bark beetle I. acuminatus may be a vector by pathogenic nematodes B. xylophilus.

Conducted study purposed to assess the dynamics and condition of vegetation cover in North-taiga Arctic region, using the Arkhangelsk region as a case study. This involved processing satellite imagery with the calculation of several vegetation indices. The results of the NDVI analysis for 2013 revealed a maximum value of 0.7 and a minimum of –0.25, with an average of 0.30. Values were distributed closely around the mean. By 2022, the average vegetation coverage index had increased to 0.34, suggesting an improvement in vegetation coverage over the study points. The percentage changes were calculated by comparing NDVI values over the study years. The results showed a decrease of 14.29% in areas representing moderate vegetation cover, while areas representing good vegetation cover increased by 15.49%. This increase is attributed to tree growth, improved canopy coverage, and increased vegetation density in 2022, which is a result of effective forest management practices, including thinning and reforestation measures. Analysis of the vegetation aging index indicated values close to zero in 5% of the total study area, while positive values exceeding 0.2 were observed over a significant portion of the region. These findings suggest physiological stress, partial chlorophyll degradation, and the initiation of conversion to carotenoids. The results of the analysis of biophysical indicators showed that the vegetation cover in the study area is in the average state. The average leaf area index was 1.87 over most of the study area, indicating the absence of high densities of vegetation. The average value of the chlorophyll index in the leaves was 88.61, which is also a low value and indicates weak chlorophyll content, which indicates physiological stress and low efficiency of the photosynthesis process.

Deciduous coniferous forest stands occupy a significant area among the forests of the taiga zone. The formation of valuable coniferous formations in such areas is a fundamental goal of the forestry. One of the possible ways to achieve this goal is timely and quality thinning at various stages of forest stands formation. The aim of the study was to determine the silvicultural efficiency of three-stage thinning in deciduous coniferous forest stands formed in the taiga zone. Long-term scientific studies have been carried out since 1966 on permanent sample plots one of which is a control option, the second is an experimental version with thinning at the age of spruce 20, 28 and 40 years. During the first thinning, spruce (65% by the number of trunks), birch (80%) and pine (60%) were cut down evenly over the area, at the second rarefaction – 80, 65 and 50% of the trunks (of the number of trees preserved after the first intake), respectively, at the third thinning – 15, 60 and 70% of the trunks (of the number of trees preserved after the second intake), respectively. Carrying out three-stage thinning in deciduous and coniferous stands growing in the taiga zone of the European North of Russia gave a positive silvicultural effect. As a result of thinning carried out, the average annual increase in diameter, height of trunks and stock of stem wood grew. By thinning by the age of 74 years of forest stands, it was possible to form a coniferousdeciduous stand from deciduous-coniferous stands, where the total stock of coniferous wood is 67%. By carrying out classical thinning in deciduous and coniferous forest stands, it was possible to form stands with a predominance of coniferous species, as well as to enhance the increase in diameter, height and volume of trees trunks saved for growing.

The purpose of this study was to substantiate the system of indicators for assessing the degree of danger of climate risks in forestry. Based on the results of the study of the main approaches to the definition of climatic risks in forestry and the study of their consequences, a system of indicators for assessing the degree of danger of climatic risks in forestry was developed and scientifically justified. This system of indicators for assessing the degree of danger of climate risks in forestry is based on a pragmatic approach associated with the availability of long-term statistical data, and is supported by the latest scientific data in the field of forest ecosystem dynamics under the influence of climate variability factors. The system of indicators can become the basis for planning the implementation of adaptation measures in the field of forest use, protection, conservation and reproduction, including with regard to the main climatic risks caused by changes in forest productivity due to changes in the average values of temperature and precipitation, changes in the species (types) composition of forests, an increase in the frequency of (forest) fires in forests and areas covered by fires, an increase in the frequency of outbreaks of mass reproduction of pests. This work is aimed at forming a scientific basis for a comprehensive assessment of climate risks and developing a strategy to minimize them, this will ensure the sustainability of forestry to climate change and maintain its environmental and economic stability. The developed indicators can be integrated into existing forest management methods, contributing to the improvement of the practical implementation of adaptation measures and policies in the field of environmental protection.

The research was carried out on the territory of the Primorsky district of the Arkhangelsk region in different types of pine forests: moist bilberry pine, bilberry pine and shrub-sphagnum pine. Forest are close in age and pure in composition or with a small admixture of other species. Bilberries were collected in a systematic sequence on 1´1 m sites laid diagonally across the test area. Then, using these data, we obtained: the number of bilberries on each site, the mass of bilberries in fresh condition, the diameter of bilberries, the height of bilberries. It was found that the diameter of bilberries in different types of forest ranged from 7.06±0.06 to 7.21±0.05 mm. The differences according to the Student's criterion are unreliable. The height of bilberries from the place of attachment to the lowest point significantly differs. The highest bilberry berry is in the moist bilberry pine, then it goes down in the bilberry pine and the lowest in the shrub-sphagnum pine. The average weight of one bilberry berry in moist bilberry pine is 0.32±0.01 g; in bilberry pine – 0.34±0.08 g; and in shrubby sphagnum pine – 0.28±0.02 g. The average number of bilberries in different types of forest on a site of 1 m2 is different: in the moist bilberry pine – 62 pcs./m2 , in the bilberry pine – 39 pcs./m2 , that is almost half as much, and in the shrubby-sphagnum pine – 34 pcs./m2 . The largest mass of bilberries in the moist bilberry pine is 20 g/m2 , in the bilberry pine – 12 g/m2 and in the shrub-sphagnum pine – 10 g/m2 . The average yield of bilberries is as follows: in the moist bilberry pine – 200.6 kg / ha, in the bilberry pine – 129.5 kg/ha, in the shrub-sphagnum pine 101.6 kg / ha. There is no clear dependence of the mass of bilberries per 1 m2 on the projective coating, but there is a trend: the larger the projective cover is the greater the mass of berries per 1 m2 will be.

The paper presents the data on the variability of wood base density in the pure Scots pine (Pinus sylvestris L.) cenopopulations in the Mari El Republic. The studies were conducted on 38 plots in the stands of different ages (30 to 240 years old), origins and growing conditions in 2023–2024. In each plot, we measured tree trunks with bark and took cylindrical cores of 5.15 mm in diameter and 50 mm in length using a Pressler increment borer (Haglöf Sweden AB). The sample size in each plot varies from 15 to 30 cores. The numeric empirical material was processed by standard methods of mathematical statistics using a PC with packages of relevant applications. It is demonstrated that the assessment of the mean value of wood density, which may vary in the Scots pine cenopopulations from 320 kg×m–3 to 520 kg×m–3, requires cores from 20 or 25 trees of the average size that would ensure an error of not more than ± 3% with a probability of 99%, while for assessment with an error of ± 5%, it is necessary to take cores from 12 to 15 trees. The minimum and maximum values of the assessed parameter in each cenopopulation will be 75% and 140%, respectively, in relation to the arithmetic mean of its value. To assess this parameter, trees in the cenopopulations may be selected either regularly along the computation line or randomly, except the trees with sharply outstanding sizes. It is more appropriate to assess the base density of wood by a stereometrical method as it provides the accuracy that is not less than that of a hydrostatic method, which is more difficult and timeconsuming.

Reforestation is associated with the cultivation of planting material. An effective solution to weed control in forest nurseries is the use of herbicides. The list of chemicals for weed control recommended for forestry is limited. There is one active ingredient for each stage of the fight against unwanted vegetation, which contributes to the development of resistance in weeds. The aim of the work is to evaluate the effectiveness of tank mixtures of herbicides in the care system for spruce seedlings. Field experiments to evaluate the effectiveness of modern herbicides and their tank mixtures were carried out in the Primorsky and Vinogradovsky districts of the Arkhangelsk region on experimental ridges and in an open-ground forest nursery. The soils are light to medium loam. When selecting herbicides, we focused on the active substance tested by scientists and allowed in the territory of the Russian Federation, and the availability of drugs in the retail network. The effectiveness of the tank mixture of Tornado and Ankor-85 herbicides on meadow vegetation is 100%. After treatment with this tank mixture of herbicides for the next growing season, additional methods of weed control are not required in the first year of growing spruce seedlings. The effectiveness of weed suppression with the pre-emergence herbicide Brig is 54%. The addition of Lignohumate does not significantly affect the effectiveness of the herbicide. The effectiveness of weed suppression in the system of application of herbicides: preemergence – Brig; with linear growth of seedlings – Miura and Mortira – is 70%. The addition of lignohumate reduces the effectiveness of the tank mixture. The addition of Lignohumate to the tank mixture of Miura and Mortira herbicides contributed to a 1.8-fold reduction in damage to seedlings.

Climate change significantly impacts forest ecosystems, particularly coniferous species such as Scots pine (Pinus sylvestris) and Norway spruce (Picea abies), which form the basis of temperate forests. The adaptation of these species to new environmental conditions necessitates consideration of the genetic variability of key adaptive traits. This study investigates single nucleotide polymorphisms (SNPs) in candidate genes that regulate photoperiodic response and circadian rhythms, which are critical to tree physiological processes. The research describes the development and testing of molecular markers based on KASP (Kompetitive Allele Specific PCR) and HRM (High Resolution Melting) methods for high-throughput genotyping. SNPs were identified in the photoreceptor genes PhyO and CRY1 and the photoperiodic response genes PRR1 and PRR7. These polymorphisms exhibit geographic clinality, highlighting their significant role in tree adaptation to latitudinal gradients of light and temperature conditions. The findings confirm the efficiency of KASP and HRM methods for genotyping, enabling the use of these markers for monitoring genetic diversity and selecting resilient genotypes in breeding programs. Such approaches ensure the integration of genetically adapted planting material into reforestation efforts, which is particularly relevant in the context of changing climate conditions.

Mathematical models and scientific basics of the theory of forestry machines locomotion, revealing the nature of interaction of forestry vehicles with strengthening soils, have been poorly developed. In practice, the lack of a complete scientific description complicates substantiation of the parameters and operating modes of the vehicles compatible with strengthening soil and ground conditions and makes it difficult to select passable forestry equipment. The objective of the article is to develop and study mathematical models of rutting that take into account the variable nature of the mechanical properties of soils under the influence of movers of forestry machines. The study bases on the provisions of soil mechanics and the theory of locomotion of forestry machines. In the development of mathematical models classical methods of mathematical analysis and approximation of functions were used. Based on the solution of the rutting equation analytical expressions in elementary functions were obtained for the first time, taking into account both gradual and possible more abrupt changes in the mechanical properties of the soil with depth. The obtained expressions will allow conducting computational experiments with a mathematical model of the interaction of the machine propeller with the soil in particularly difficult conditions represented by sodded soils (a stronger upper layer on a weakly bearing underlying layer). Also, as a result of solving the rut formation equation, expressions were obtained in elementary functions, taking into account the increase in the estimates of the mechanical properties of the bearing surface under the influence of the vehicle (strengthening). The formulas were obtained for the first time and are intended for calculating the indicators of the interaction of forestry machine vehicles operating in especially difficult conditions with bearing surfaces of linearly hardening peatlands and quadratically strengthening loose snow. The models were implemented in Python programming language. The results of calculating the rut depth formed on loose snow when a wheeled forestry machine is moving, as well as estimates of the coefficient of the rolling resistance are presented.

The article analyzes the design of the vibration mechanism with a counterweight of the gripping-cutting device, which ensures the balancing of the resulting forces and moments of forces. The design development of the vibration mechanism of the gripping-cutting device was performed by adding one counterweight, which will provide the required unloading of the supports from the unbalanced masses of the vibration mechanism. To analyze the design of the vibration mechanism with a counterweight, the mass of the counterweight was determined by calculating the translational moving and rotating parts of the mechanism. Dynamic studies were carried out in the SolidWorks Motion program on the developed 3D model of the vibration mechanism design with a counterweight. As a result of the analysis of the design of the vibration mechanism equipped with a counterweight, the moment on the mover was simulated and the values compared with the simulation results obtained on the vibration mechanism without a counterweight for a tree weighing 50 kg and at a rotation speed of the mover of 150 rpm. Comparison of the results of modeling the torque on the vibration mechanism drive under equal conditions showed that the maximum torque on the shaft without a counterweight is 435804 N mm, and the maximum torque on the shaft with a counterweight is 331931 N mm. The difference in the values of the maximum torques on the vibration mechanism drive shaft showed that the use of a counterweight reduces the maximum torque by 23.8%.

The article is devoted to the study of one of the problems of interaction between forestry, forestry industry and hunting, which is characterized by special relevance in modern conditions. The relationship between these sectors of the economy and the need to coordinate economic activities are determined, among other things, by the fact that the use of forests (primarily for timber harvesting) and hunting (carrying out activities in the field of hunting) is carried out on the same territory of the forest fund. At the same time, as a result of logging operations during logging of ripe and overgrown forest plantations, logging of forest care, forestry and other works, the habitat conditions of forest animals and birds can change significantly, which in turn will cause changes in species composition, population dynamics and station distribution of forest fauna. This circumstance will have to be taken into account already when conducting a hunting farm. The purpose of this study is to substantiate the need to use felling residues for biotechnical purposes as an element of logging technology in the context of the impact on forest ecology and reforestation, as well as to analyze the practice of using felling residues for biotechnical purposes in the conditions of forestry in the North-West of the Russian Federation. Based on the observations, the authors consider it possible to conclude that the use of felling residues for biotechnical purposes reduces the degree of damage to pine young moose. In addition, when carrying out logging, it is necessary to design and carry out measures to protect wildlife and their habitat. In this regard, the authors propose that activities related to biotechnical activities or pursuing biotechnical goals should be equated with activities for the protection of wildlife and their habitat. For example, the use of felling residues for biotechnical purposes, of course, should be attributed to measures to protect wildlife and their habitat.

The article deals with the modernisation of the harvester head. The aim of the work was to develop the design of a harvester head to increase the productivity of logging operations in the Far North in the presence of deep snow cover. As a result of the work the design of a harvester head equipped with an active working body capable of clearing the space around the trunks of rooted trees was proposed. The active working body provides high productivity of work with a small number of control actions of the operator. The proposed design will increase the volume of harvested timber by reducing the height of stumps left behind.

At present, planting is almost universally favored in the establishment of forest crops. In order to cover all available areas with mechanized planting it is necessary to create new forest planting machines. One of the directions of improving the technological process of mechanized planting is the improvement and development of new mechanisms for feeding seedlings (saplings) into the planting slot formed by the coulter. To justify the parameters of the forest planting apparatus, it is necessary to determine the movement parameters of its links. To analyze the kinematics of forest machines use automated software such as SolidWorks, Matlab/Simulink. However, the use of foreign software does not meet modern trends, so we used domestic software packages. The three-dimensional model of the chain planter was made in the 3Ddesign environment KOMPAS-3D. Analytical systems of equations obtained on the basis of geometric parameters of the three-dimensional model were entered into the developed simulation model. Thus, the simulation model of motion of the chain planting machine was developed taking into account the geometric parameters of the design and analytical systems describing the motion of the grippers with a seedling. The simulation experiment carried out in the software package of modeling mechanical systems «Universal Mechanism 9.0» allowed to determine the characteristics of the movement of the seedling briquette necessary for its installation in the ground, as well as force parameters in the grippers for its retention. The positions of the links of the designed working body of the planting machine are established throughout the simulation time. The time points of the seedling and briquette feeding for the specified input values are determined. The trajectories of the briquette movement in the landing plane and its speed are determined. The forces on the springs are determined, sufficient to hold the seedling with a briquette in the grips.

Workers in the logging industry are often limited to assessing the operational efficiency of a skidder by only two indicators, transport productivity and specific energy intensity of the skidding process, but in order to achieve rational use of logging equipment modern instrumentation is needed to select the optimal routes for the movement of machines in the cutting area. It is proposed to create maps of cutting areas, similar to navigational ones, which should reflect the soil-ground, relief and other properties of the supporting surface that determine the operating modes of the machine. To solve the tasks set, it is necessary to measure, record and mathematically process the results of the study of indicators and processes using the theory of probability. Knowledge of the fracture angle of the articulated frame and the torque supplied to the drive wheels will make it possible to obtain the laws of distribution of the tangential thrust force for assessing the dynamics of the process, the energy intensity of the process, various coefficients of resistance to movement, traction efficiency, etc. When skidding a pack of wood, the skidder can be in rotation mode with different radii of curvature up to 70% of the time, while the resistance from turning affects the movement. This resistance can far exceed the force of resistance to movement. To solve the research problems, it is proposed to introduce the coefficient of resistance to movement into the traction balance of logging and forest transport machines, as the sum of the coefficient of resistance to rotation and the coefficient of sliding resistance of wood. Reasonable indicators for assessing the interaction of a skidder with a supporting surface and methods for their instrumental determination will make it possible to choose from a large set of rational dragging routes, the skidding of wood along which will allow you to get the maximum operational efficiency of the skidder.

Delivery of wood raw materials to consumers from the most remote forest areas, where its main reserves are concentrated, is often economically justified only when carried out by waterways. When branched river networks are used effectively, the initial relatively short part of the delivery route usually passes through shallow water areas. After overcoming them, it is economically feasible to enlarge timber transport units. The device discussed in the article, together with logging equipment, allows for the enlarge of timber transport units in an efficient and environmentally friendly manner. With its help, smallsized packages without compromising their integrity are assembled into two-tier, fourpacket bundles. Operating the device involves moving it from place to place. The described study is aimed at obtaining reliable information about the hydrodynamic loads acting on the device in operating condition. Their presence will ensure its reliable fastening, while avoiding excessive costs. Factors have been identified that theoretically influence the magnitude of these loads. The relationship between the hydrodynamic load and the determining factors is reduced to dimensionless form. The admissibility of excluding the Reynolds number from the number of determining factors is substantiated. Dimensionless geometric factors characterizing the shape of the underwater part of the device and the base timber transport unit are fixed. As a result of theoretical studies, an analytical formula was established by which the hydrodynamic load perceived by the device should be determined, and the dependence of the hydrodynamic resistance coefficient on the Froude number and the relative depth at the place of work was obtained, presented in symbolic form. Using this dependence, experimental studies were carried out on a physical model in compliance with similarity using a full factorial design. Based on the results of the experiments, regression models were obtained to calculate the values of the hydrodynamic resistance coefficient in the case under consideration. Knowing this value allows one to determine, using the mentioned analytical formula, the hydrodynamic load on the device with the timber transport unit located in it. An analysis of the influence of the main determining factors on the value of the coefficient under study was carried out.

Polyurethane-based LKM are widely used for finishing medium-density fiberboards (MDF) employed in the production of furniture fronts and wall panels. These materials are characterized by high strength, as well as mechanical and chemical resistance. The curing process of these coatings is a critical stage that determines the quality of the final finish and is influenced by temperature and application rate. This study investigates the curing process of opaque polyurethane primers with the aim of optimizing production conditions. The experimental research included a full factorial experiment, which allowed for establishing the dependency of curing time on key parameters. A mathematical model was developed to quantitatively assess the influence of temperature and application rate on curing time. The optimal temperature range for drying polyurethane primers was determined, which minimizes the risk of coating defects and ensures high product quality. The results of the study can be used to optimize production processes, reducing operational costs and increasing energy efficiency. A statistical comparison of domestic polyurethane primers with foreign analogs may significantly contribute to the import substitution process, enabling the comparison and assessment of efficiency. The development of domestic materials based on the obtained data will ensure more competitive production and independence from imported supplies.

The article considers the process of moisture transfer in wood during its hydrothermal treatment. Obtaining a high-quality dried material with minimal internal stresses is possible based on information about the amount of moisture current in the wood, expressed in terms of the moisture conductivity coefficient. The coefficient of moisture conductivity is greatly influenced by temperature, with an increase in which its value increases significantly. The intensity of the moisture current in the wood is influenced by the breed, the direction of the moisture current and the location of the wood in the tree trunk. The available information on the moisture conductivity of wood does not take into account the variability of the density of wood in the height of the tree trunk and is presented for the butt part of the trunk. The determination of the moisture conductivity coefficient was established in the radial and tangential directions for sound pine wood, taking into account the height of the trunk by the method of stationary moisture current. Experimentally, an increase in the value of the moisture conductivity coefficient of pine wood in the height of the trunk in its middle part by 1.6 times, and in the apex – by 2.05 times compared with the lump. The intensity of the moisture current in the radial direction is higher than in the tangential direction in wood from the butt part of the trunk by an average of 14.0%, from the middle part of the trunk – by 5.0%, and from the apex – by 16.0% regardless of the ambient temperature. The obtained patterns on the variability of the moisture conductivity coefficient of pine wood in trunk height show the expediency of carrying out preliminary sorting of wood before hydrothermal treatment, taking into account its location in the trunk of the tree. This will optimize the processes of drying and moistening of wood, justify rational modes of chamber and atmospheric drying.

The properties of sunflower seed shells were studied in order to use husks in the manufacture of slab materials. To eliminate the unacceptable shape of the "boats", they were shaped into flat particles by passing husks through rolls with a set lumen value of 0.1...0.4 mm. A deterioration in the wettability of the urea-formaldehyde binder solution of the outer and inner surfaces was found when heated to a temperature of 140 °C. The hardness of the husk increased in terms of softening compared to wood and the boundary values of the hot pressing parameters, which range from 241 ± 2 °C – the lower value, to 256 °C – the upper value, which is limited by the active thermal decomposition of the husk substance, were established. For the practical use of husks in the production of plates, it is necessary to include increased binder consumption in the technology or develop suitable husk plasticization techniques to reduce the softening temperature and the possibility of using pressing equipment, the potential for modernization of which has already been exhausted. The probable area of manufacture of slab material from husk is construction, the probable grades of plates – P-1 and P-2.

The formaldehyde/urea (F/U) molar ratio is one of the main parameters determining the formulation of urea-formaldehyde (UF) resins. The molar ratio largely determines the structure of the main components of the resin (UF oligomers, methylol derivatives of urea), as well as the properties of the resins and materials manufactured using them. The aim of this work is to research the structure of the UF resins synthesized at different F/U molar ratios; to assess the effect of the molar ratio on the properties of the resins and particleboards manufactured using them. It was found that the low molar ratio UF resin (F/U = <1.1) consist mainly of linear oligomers containing a insignificant amount of type II methylol groups. During curing of low molar ratio resins, a network structure with an insignificant amount of cross-bridges is formed, which negatively affects the water resistance of particleboards. With an increase in the F/U molar ratio, the number of branches of UF oligomers increases, also the content of methylol groups increases and the reactivity of the resins increases. Cured medium and high molar ratio UF resins (F/U = 1.1–1.2 and >1.2) are distinguished by a dense cross-linked structure and ensure comparatively high physical and mechanical properties of particle-boards. At the same time, an increase in the F/U molar ratio leads to a significant increase in the formaldehyde content in particleboards.