Various zones from the tundra to the steppes and mountain forests are formed in the Yenisei Siberia of the coniferous boreal zone, stretching from north to south for 30º. Agrarian nature management is developed in almost all zones, with the exception of the arctic, subarctic and tundra, there is reindeer breeding in the last two. Active nature management begins with the southern taiga and subtaiga zone. The article deals with the organization of agricultural territories. The analysis of the structure of the agropotential of natural resources made it possible to identify the originality of the composition, the ratio of individual species and the natural prerequisites for the economic development of the agricultural sector in the zone of active farming of the Yenisei Siberia. The analysis of the existing regional systems of agrarian nature management (regional and topological levels) allows us to identify not only the features of their formation, but also to suggest directions for rationalization and sustainable development within the framework of natural and socio-economic restrictions in the future. In this paper, on the example of the Yenisei Siberia, the approaches to the assessment of the agro-natural potential of the territory and agricultural nature management as an ecological and economic system are analyzed and presented. The sustainable development of the Yenisei Siberia is based on the integrated development of its three components: social, environmental and economic. It is important to take into account the environmental factor, which is defined as the ecological potential, the reserve of the territory's ability to satisfy human needs in agricultural products and withstand negative anthropogenic impacts.

The basis of the modern economy is the processes of interaction between nature and society, which is carried out in the conditions of regional nature management, characterized by such features as natural-historical unity and integrity, individuality and impact. The article analyzes the economic factors and prerequisites for the modern development of the Krasnoyarsk Krai within the boreal zone of the Yenisei Siberia, and determines the main directions for optimizing agricultural production in the new socio-economic conditions, considers indicators characterizing the dynamics and level of development of this sector of the economy. The population size, density, potential of crop yields in various landscape zones of the Yenisei Siberia are analyzed, taking into account the natural and economic conditions of the territory. The analysis of modern approaches to the development and implementation of the concept of sustainable development in the field of agricultural production has shown that the qualitative and quantitative assessment of the natural resource potential of the territory becomes an important argument for optimizing nature management and the basis for making decisions on land use. An economic assessment of the land based on the identified agro-natural areas will determine to what extent it is possible to promote the cultivation of various crops to the north (to the region of the southern taiga and subtaiga), where, according to the agro-climatic potential, it is possible to increase significantly the productivity of these territories.

The growth of tree formations on the border of their range is due to the influence of a whole range of negative factors, primarily climatic conditions. All this affects both the development of plantations and their growth.
Scots pine (Pinus sylvestris L.) is characterized by plasticity, which allows this tree species to have a huge range and the ability to grow both in mountainous conditions and in northern cold areas. The study of pine forests was carried out on the basis of taxation materials of forest inventory. The object was the pine forests of the Baikit forestry, located in the conditions of the Central Siberian plateau of the Krasnoyarsk Krai. The most common type of growing conditions: fresh sandy and loamy soils. Unfavorable growing conditions contribute to the formation of low-grade forest stands (IV grade – 35 plots, V grade – 45 plots). The age of observed forest stands is from 5 to 260 years. The average height varied from 1 to 22 m. The stock varied from 10 to 210 m3/ha. The soils are decomposed podzol on gravelly soils predominantly. Based on the analysis performed, it was found that the difference in growth rates in pine forests of different types is mainly due to internal (endogenous) factors characterizing forest stands (species representation, density, degree of uneven age, etc.). That explains the presence of pine forests of IV and V classes of bonitet under these conditions. A table of the dynamics of taxation indicators of modal pine forests of the green mosslichen group of forest types on the border of growth in the conditions of the Krasnoyarsk Krai has been compiled. Based on the table of the dynamics of taxation indicators, a standard was developed for assessing the biological and carbon productivity of modal pine forests according to the main fractions (trunks, branches, roots, needles). It has been established that pine forests are characterized by a sufficiently high durability. They have a pyrogenic or sublingual origin. The age of natural ripeness is at 220 years.

Coniferous-deciduous forests in the southern part of the Far East are a unique collection of tree species left to us from the tertiary period. Many families, genera and species grow here. A prominent representative of the Olive family (Oleaceae Hoffmgg.et Link) is a genus of ash (Fraxinus L). The genus is represented by Manchurian ash (F. mandshurica Rupr.). In natural conditions, it forms ilmovo-ash, and sometimes ash uremes. Manchurian ash grows as part of coniferous-deciduous forests, occurs both in single specimens and in small groups. It does not form one type of plantings. In some allotments, its share can reach 40 % of the total stock of planting. The maximum age of individual trees reaches 200 years or more, height is 25–30 m, diameter is up to 1.0 m. The trunks are straight, full-timbered, the crown is openwork, the bark is smooth. It requires fertile soils. On well-drained soils, it shows a high growth rate, especially at a young age.
As a consequence, quantitative ripeness in the planting occurs at the age of 40, technical one occurs at 80 years. It has a high winter hardiness, which provides it with advantages over other species in afforestation in northern areas. It is ornamental and tolerant of crown pruning in urban plantings. The regulatory framework compiled for this species includes growth progress tables, volumetric, assortment and commodity tables. Growth progress tables are compiled for three types of forests and characterize the dynamics of taxation indicators between 10 and 100 years. In this article, based on the materials of the state forest inventory, a growth progress table for Manchurian ash was constructed. The experimental material included 121 model Manchurian ash trees. The average values of heights, diameters and reserves are equalized using a parabola of the 2nd order. The dynamics of the average values of taxation indicators is calculated in the growth progress table: height, diameter and available stock.
The output of large plus medium-sized business timber has been determined. According to these data, the age of quantitative and technical ripeness of the forest has been established. The listed indicators reflect the dynamics of the average data for this forest-forming species. The accuracy of determining the stock is not less than 5%. Taking into account the high production characteristics of Manchurian ash, the developed standard can be considered an addition to the existing regulatory framework, which is important for the intensification of forestry production in the region. The developed tables can be used to assess and forecast wood stocks in plantings with the participation of Manchurian ash.

The ground cover of forest crops at the initial stages of the formation of forest plantations are unique forest biogeocenoses, characterized by peculiar ecological conditions, features of regenerative succession and biological diversity of the ground cover.
The features of restorative successions of herbaceous vegetation at the initial stages (the second decade) of the formation of pine and spruce forest crops in the conditions of the former glacial felling from under cranberry pine on the territory of the Kargopol forestry in the southwestern part of the Arkhangelsk region are studied.
The purpose of the research is to study the floral composition and ecological–cenotic structure of the ground cover of forest crops, depending on forest growing conditions and methods of tillage.
The species richness of plants on experimental plots of forest crops with different methods of soil preparation varies from 32 to 39 species. The coefficients of similarity of the species composition of the flora in the studied sample areas vary from 0.63 to 0.80.
The floral composition of the ground cover is mainly represented by species of the mesophyte group (87%). Depending on the illumination conditions, heliophytic (47%) and semigeliophytic species (38%), growing in a wide range of illumination predominate. Mesotrophic species predominate in terms of plant requirements for soil nutrition (89%). No plants from the oligotrophic group were found on the studied area.
The studied plant communities at this time stage are characterized by the predominance of meadow species (64%) with a significant participation of forest species (36%). Based on the analysis of the phytocenotic structure, it can be concluded that more than half of the species of living ground cover are accidental and temporary species that are weeds of forest nurseries of the Middle Taiga subzone (51%). At the same time, the abundance of most species of the weed group is less than one.
The classification of phytocenotic activity of plants is given. The basis of the community consists of highly active species (Deschampsia caespitosa L., Calamagrostis epigeios L., Trifolium pratense L., Rubus saxatilis L., Chamerion angustifolium L.), most of which were represented at the glacier cutting before the creation of forest crops. Low-active and inactive species make up a significant part of the species spectrum (43%). Groups of low-active and inactive plants are characterized by high cenotic diversity.

The identification of the influence of the geographical factor on the introgressive hybridization of spruce populations is necessary for the organization of forest seed production on a genetic-breeding basis. The paper presents the results of a comprehensive assessment of the degree of hybridization of European and Siberian spruce in the populations of the central part of the Vologda Oblast. The signs of the variability of the structure of cones proposed by I. A. Korenev (2008) were used as markers. Studies have shown the presence of significant differences in the morphometric parameters of cones in the populations of the considered part of the area, as well as in the level of their variation. Among the studied populations according to the signs of qualitative variability (the angle of sharpness of seed scales, the shape of underdeveloped scales, the shape of the lateral edge of seed scales, the type of termination of seed scales) the maximum average score determined by the method of I. A. Korenev was noted in the Vologda population. A comprehensive score assessment of the morphometric parameters of the cones revealed significant differences in the degree of hybrid between the studied populations. In general, the principal points of introgression of spruce populations within the north of the East European Plain have been confirmed. The increase in the influence of Siberian spruce is most pronounced as it moves from west to east along the line Kharovsk – Syamzha – Totma. The research results indicate that the degree of introgressive hybridization is also conditioned by the orographic factor. The degree of introgressive hybridization is influenced by the confinement of the Totma population to the banks of the Sukhona river. The article concludes that the degree of hybridization of European and Siberian spruce populations is connected with their geographical location. This factor should be taken into account when carrying out breeding work. When selecting, it is recommended to give preference to individuals of the dominant hybrid forms.

Understanding the effects of climate change on tree growth is necessary to predict forest dynamics in future climate change scenarios. In this regard, the role of empirical models that adequately describe the variability of biological productivity of forests and allow predicting its change under the influence of climatic shifts is increasing. In the available publications, the contribution of climate variables to the explanation of biomass variability is either insignificant or zero, mainly due to the regional level of models. The modeling of the biomass of trees and stands performed at the Eurasian level showed the presence of a statistically significant contribution of winter temperature and average annual precipitation to the explanation of the variability of biomass indicators. However, the validity of using winter temperature instead of summer one in predictive models was questioned. The purpose of this work was to study the relationship of temperatures of different months in Eurasia and their changes in the latitudinal gradient from the tropics to the forest tundra in order to identify the month whose average temperature would be statistically significant in biomass models. To achieve this goal, the WorldClim version 2.1 climate database for the years 1970-2000 was used (https://worldclim.org/data/index.html). It is established that the average summer temperature provides a weak geographically distributed climatic signal, which is not capable of being extracted from the general dispersion of factors determining the biomass of trees and stands. On the contrary, the average January temperature represents a sufficiently strong geographically distributed climatic signal due to the high ratio of the total variance (or temperature range) to the residual one, which provided the statistical significance of the previously identified influence of winter temperatures on the biomass of trees and stands of forest-forming genera of Eurasia [4]. The average annual temperature, characterized by a high correlation with the January temperature, may be statistically significant in explaining the variability of biomass of trees and stands of Eurasia. The identification of this premise will be a subject of our further research.

The main purpose of the work is: to determine the features of knifeless refining of fibrous semi-finished products, taking into account a complex parameter based on the coefficient of dynamic viscosity of fibrous suspensions; development of a new method for determining the viscosity of fibrous suspensions.
For fibrous suspensions, ceteris paribus, an increase in the concentration of the working medium leads to a decrease in the flow rates. This is due to the fact that with increasing concentration, the viscosity of the studied liquids increases. For water, that is, a Newtonian fluid, the value of the outflow velocity is the largest value.
To determine the coefficient of dynamic viscosity during knifeless refining of the fibrous mass, in addition to the values of the fibrous suspension flow rate, it is necessary to calculate the shear area of the layers during the flow of fibrous suspensions in the cavity of the working cylinder and determine the shear force.
The publication presents an analysis of the flow of fibrous suspensions in the process of refining fibrous semifinished products in a knifeless way. For this, theoretically, with the elements of the experiment, the shear forces of the layers of the fibrous suspension flow in the cavity of the working cylinder are determined.

This work is devoted to the continuation of the research of the authors to establish patterns of influence of the number of thicknesses of boards in the set on their volume output. The results of these studies are presented in this journal in the article “Dependence of the volumetric yield of lumber on the number of their thicknesses in the set”. To refine the revealed implicit dependencies, the values of the decrease in the volumetric yield of sawn timber in optimal sets for various diameters and lengths of logs were determined. It has been established that when sawing, for example, logs with a diameter of 22 cm and a length of 3.0 m, the tightening of restrictions from “no more than 4 thicknesses in the set” to “no more than 3” when optimizing the set leads to a decrease in volume output by 1.43 %. Further tightening to “no more than 2 thicknesses” leads to a decrease in volumetric yield by 1.37 %. The analysis of the obtained results shows that the change in the volumetric yield of sawn timber with a change in the diameter and length of the logs is oscillatory due to the continuity of the log dimensions and the discreteness of the dime nsions of “lumber fit into the log”. To reduce the interfering effect of fluctuations in determining the influence of the diameter and length of a log on the magnitude of the decrease in the volumetric yield of lumber due to the small thickness of the posts, we expanded the ranges of compared diameters and lengths of logs and switched to average values. It was found that the average decrease in volume output for optimal sets and diameters of 14 and 30 cm is 0.82 and 1.56 %, respectively, and for log lengths of 3.0 and 6.5 m – 1.57 and 0.83 %. For deliveries close to optimal, the reduction is 1.3; 1.83 and 2.41; 1.24 %. Thus, tightening the limit on the number of thicknesses of boards in a set leads to a decrease in the volume yield of sawn timber by a value that depends on the diameter and length of the log: the larger the diameter and the shorter the length, the more the volume yield depends on the number of thicknesses of boards in the set.

When designing the production processes of large sawmills with batch handling of sawn timber, there is a question of optimizing the number of thicknesses of boards in a set. Currently, the problem of choosing the number of thicknesses in the set is getting a new sound, since log sawing equipment with flexible sets is becoming more widespread in sawmilling, when the optimal set is automatically set for each log in accordance with its shape and size. This sort of assortment optimization is once again pushing sawmills to increase the number of thicknesses in the set. When designing the production processes of large sawmills with batch handling of sawn timber, there is a question of optimizing the number of thicknesses of boards in a set. Currently, the problem of choosing the number of thicknesses in the set is getting a new sound, since log sawing equipment with flexible sets is becoming more widespread in sawmilling, when the optimal set is automatically set for each log in accordance with its shape and size. This sort of assortment optimization is once again pushing sawmills to increase the number of thicknesses in the set. The tightening of restrictions from “no more than 4 thicknesses in the set” to “no more than 3” leads to a decrease in volumetric yield from 0 to 0.2072 %, and – from “no more than 3” to “no more than 2-x” – from 0 to 1.2639 %. The transition to the restriction “no more than 1 thickness” from “no more than 2” causes a very significant decrease in volume output by 3.6760 ... 6.5691 %. If it is possible to neglect the decrease in volume yield to 0.2 %, then four-thickness fittings should be excluded from consideration, and if it is acceptable for reasons of harmonization of the production process to reduce the yield to 1.3 %, then it is advisable to also refuse three-thickness fittings. With some combinations of log sizes, when switching to small-thickness logs, a jump in volume output losses is observed.