The basic density of wood (BD) as the ratio of the mass in dry condition (at 0% humidity) to the "green" volume (the volume of wood in a state of saturation with water) is an useful indicator in studies of the carbon cycle and plant ecology. Data on the wood BD of most species within the region are often unavailable, and averages at the level of genera or families are used. However, there may be significant phylogenetic and geographical variability of BD, and the use of its average values at the genus level is possible only in the absence of regional data. Almost all published data contain information on the BD of the wood itself, excluding bark. If it is necessary to calculate the biomass of stems above bark according to the available volume data having in mind the BD, which differs for wood and bark, then it is impossible to obtain the desired result with sufficient accuracy, since in each specific case the ratios of wood and bark are unknown, and they differ significantly. The presence of huge amounts of data on volume stocks accumulated by traditional forest taxation makes it possible to estimate the dry biomass of stems with the bark over large areas using known values of the stem BD. The purpose of our research was to analyze the regional features of stem wood BD of coniferous tree species of Eurasia. Using the author's database on the qualimetry of trees of forest-forming species of Eurasia, a sample of 3220 trees of five coniferous tree genera (subgenera) of Eurasia was formed. A mixed-type model structure is applied, including numerical (age and stem diameter) and dummy variables encoding geographical regions. Two rankings were performed according to the BD of stem above bark, namely, the ranking of clusters (regions) within the genus (for five-needled pines – within the subgenus) and a species-specific ranking, according to which the maximum values are characterized by larches and the minimum ones by firs. The obtained models and the ranking of species by the value of the BD of the stems above bark can be used to calculate the carbon pool in coniferous stands according to forest inventory data.

Krasnoyarsk Krai is part of the coniferous boreal zone of Yenisei Siberia, stretching for thousands of kilometers from north to south and west to east. In connection with this, a diverse natural resource potential is formed on its territory, creating prerequisites for the development of various types of agricultural activity. The article identifies and evaluates the leading components of natural complexes from the point of view of their favorableness for agricultural production. A summary assessment of individual areas, of natural landscapes is given, the main natural and agricultural zones in the region are identified and characterized.

Preparations with a growth-stimulating effect are beginning to be actively used in forest nursery mainly for growing planting material of the main forest-forming species. There are practically no science papers concerning the growth of these seedlings in forest cultures. A study was carried out of the influence of biological preparations Verva and Vervael on the size and morphology of Scots pine seedlings when grown in a nursery in soil where the herbicide was added, and after planting them in silvicultural areas. It was established that a single use of the preparations Verva and Vervael for pre-sowing seed treatment increased the biometric parameters of pine seedlings in the nursery from the experimental variants compared to the control one. The forest cultures that were created from these seedlings at the end of the third year of growth had a stem height and diameter exceeded the control values. The survival rate of cultures was maximum in the variants using the preparations Verva and Verva-el at a dose of 0.1 ml/kg of seeds.

The results of studies of the development of Siberian pine seedlings (Pinus sibirica Du Tour), grown in Plantek-81F cassettes in greenhouse conditions during February–May 2024, are presented. Experimental compositions of substrates based on neutral peat “Agrobalt-garden” and peat of local origin (from a deposit in the Krasnoyarsk Krai) were used. Perlite, vermiculite or coconut fiber were used as additional substrate components.

The seedlings have a significantly longer subcotyledon length when vermiculite or coconut fiber is added to the Agrobalt-Garden peat in equal proportions; this indicator is less, when perlite is added. The addition of vermiculite also has a positive effect on the linear dimensions of the aboveground part of Siberian pine seedlings, when using peat of local origin as the main component of the substrate.

The article evaluates the factors influencing the process of extinguishing forest fires. The analysis of the dynamics of the number of victims of accidents, including fatal cases in the period 2016–2023, is given. The distribution of accidents according to the severity of the consequences and by type of accidents, including the use of aviation, is also provided. A comparative analysis of known cases where several people (4 or more) were simultaneously injured in incidents with aircraft that occurred during forest and wildfire extinguishing operations, by individual countries and years in the period 1970–2023, is given. The analysis uses data from statistical and operational reports of regional and federal dispatching services. The results of the expert assessment of specialists of forest fire formations were used. The classification of cases of injuries in extinguishing forest fires according to the severity of the consequences is given. It has been established that the proportion of severe and fatal cases is consistently in the range 20–40 % of the total. The risks of injury when using aviation reach 35–40 % of all accidents. This is mainly due to the activities of paratroopers, firefighters, parachutists, and observer pilots. Three risk groups were noted: accidents related to the state of health (arthropod and snake bites, heart failure, poisoning, diseases, etc.) – 6 %, accidents that occurred during measures to deliver workers to the fire and back (crossings on foot in the forest, trips by land and water transport) – in total 41 %, accidents caused by the impact of negative factors of the production environment (working with moving mechanisms and sharp tools, falling trees and branches at the work site, thermal burns, etc.) – 53 %. A comparison of the situations in Russia and the United States shows a similar dynamics of worker deaths due to the main causes of accidents. Ananalysis of deaths shows that peaks in worker deaths are associated with group episodes. Groups of factors affecting the level of injury and the degree of negative consequences are identified.

Currently, special attention in the forestry industry is paid to the trend of creating complexes of technical systems that should ensure complete mechanization of all technological processes, increase the service life of machines and mechanisms, and reduce the costs of maintenance and repair. Improving the transmission of forestry, transport, and road-building machines is an important and urgent task. The reduction in the rigidity of the kinematic chains of thetransmission, including an increase in the elastic characteristics of the axle shafts, is explained by the need to reduce the intensity of oscillatory processes and improve the dynamic qualities of the power drive. Reducing the rigidity of axle shafts while maintaining the linearity of their elastic characteristics effectively reduces the amplitudes of dynamic vibrations under moderately loaded steady-state operating conditions, but can lead to significant overloads under unsteady transient conditions. The paper proposes one of the approaches to selecting the optimal nonlinear elastic characteristics of the axle shaft based on statistical dynamics, multicriteria optimization and the theory of mechanical vibrations. Experimental studies of the dynamic load of the transmission have shown that of the steady-state operating modes (traction, bulldozing, etc.), the highest average static and dynamic indicators are observed during soil bulldozing (Mma = 4200 Nm, bt = 600 Nm). An axle shaft with calculated elasticity indicators reduces the dynamic components acting in the kinematic chain of the engine – chassis by up to 50% and increases the fatigue life of transmission parts from 1.5 to 7 times. The proposed methodology can be applied at the design stage in order to reduce the dynamic load of the transmission.

This article presents the kinematics and dynamics of the tooth of the device for the destruction of the soil crust in the spring period on the seed beds (ribbons) of seedlings of the first year of sowing.

A dense airtight soil crust is formed on the seed beds, which prevents oxygen from reaching the root system of seedlings of the first year of coniferous seedlings. Existing devices, when loosening, shift the fragments of the crust together with the weak roots of seedlings, especially Siberian cedar pine, which leads to damage of seedlings and a drop in the yield of planting material.

The scheme and design of the tool for loosening the soil crust without damaging the root system of seedlings are proposed.

The ripper is a hinged device consisting of a crankshaft, on the cranks of which the teeth of the soil crust ripper are pivotally mounted. The gear ratio of the crankshaft drive from the support wheel is selected from the condition of ensuring equality of the translational speed of the chassis and the portable translational movement of the crank centers. The loosening depth can be adjusted.

Using the Chebyshev method, theoretical substantiations of the kinematics and dynamics of the ripper tooth were performed.

The speed of the crank axis is calculated and a velocity plan and an acceleration plan are constructed. The calculations took into account the moment of friction and the mass of the tooth. If, for design reasons, the actual weight differs from the calculated one, then a compensatory removable load must be installed on the tooth axis.

Based on the above, it can be concluded that it is advisable to create a prototype design of the considered tool for loosening the soil crust without shifting the root system of seedlings relative to the soil horizon.

Severe weather conditions have a significant impact on the operation of forestry machines equipped with hydraulic equipment. Research has shown that 75% of the vehicle fleet operates in conditions of sub-zero temperatures, strong winds, rain and snow, and reduced daylight hours for 7 to 9 months of the year.

The reduced thermal operating conditions of hydraulic systems in the Far North (Komi Republic) are a characteristic feature of the operation of modern forestry machines. Difficulties in ensuring optimal thermal conditions and the condition of the main components and assemblies of the machine and, especially, the hydraulic system lead to increased wear of parts, reduced service life and, accordingly, their more frequent replacement [1].

The accumulated experience in operating hydraulic systems allows us to say that the performance of hydraulic systems is directly dependent on the thermal load of the elements of the entire system [2]. The operation of machines, mechanisms, components and systems in the Far North proceeds under rather severe operating conditions [3].

The study of heat transfer in hydraulic tanks of forestry machines in the Far North is an urgent task related to optimizing the operation of these machines in extreme climatic conditions. The Far North is characterized by low temperatures, which can lead to freezing of the working fluid in hydraulic systems and a decrease in the efficiency of equipment.

The purpose of this study is to study heat exchange processes in hydraulic tanks of forestry machines in the Far North and develop recommendations for optimizing the cooling system to prevent freezing of the working fluid.

The pulp and paper industry mainly uses lignocellulose raw materials obtained from both gymnosperms (coniferous trees) and angiosperms (deciduous trees), while preference is given to gymnosperms in various technological applications. This preference can be explained by the properties of the fibers inherent in gymnosperms, which, as a rule, are longer than those of angiosperms. Fiber morphology, in particular the length of cellulose fibers, plays a crucial role in the paper production process, significantly affecting the paper-forming properties of cellulose, as well as the mechanical and physical characteristics of the final products. Given the growing demand for sustainable and environmentally friendly methods, the pulp and paper industry is exploring the potential of using annual plants as an alternative source of raw materials. It is extremely important to investigate the fundamental differences in the cellular structure and chemical composition of these alternative fibers compared to traditional wood fibers, especially from conifers.

The possibility of obtaining microcrystalline cellulose using prehydrolysis grinding is shown on the example of samples of dry-resistant coniferous wood. Cellulose from the bio-damaged wood was isolated with a cooking solution, the main components of which were sodium hydroxide and sulfide (NaOH and Na2S). Cooking was carried out in a laboratory autoclave at a maximum temperature of 170 ° C for 3 hours, the liquid module was 4.8, the degree of sulfidity of the cooking solution was 18%. To increase the content of alpha-cellulose in cellulose, two-stage bleaching and refining were carried out. The grinding of the fibrous mass took place on an experimental knife-less installation of the “jet–barrier” type (grinding conditions: the concentration of the fibrous mass was 1 %, the degree of grinding varied from 15 to 85). The chemical composition of the fibrous mass after grinding has been determined. Chemical treatment of cellulose samples with different degrees of grinding was carried out at the following parameters: hydrolysis temperature from 80 to 100 °C, hydrochloric acid concentration from 54.75 to 91.25 g/l, hydrolytic degradation time from 60 to 120 min. The nature of the change in the degree of polymerization of microcrystalline cellulose depending on the de-gree of grinding is analyzed. It was found that with an increase in the degree of grinding of the fibrous mass from 15 to 85 °C, the crystallinity index of MCC varies from 0.64 to 0.78; the degree of polymerization from 350 to 95. A linear regression equation has been obtained to determine the effect of technological parameters on the degree of polymerization. It was found out that the degree of polymerization of microcrystalline cellulose is decisively influenced by the degree of Shopper–Riegler grinding. The developed technology for producing microcrystalline cellulose makes it possible to solve the problem of recycling of bio-damaged wood and reduce the cost of obtaining MCC by 1.5 times.