The article deals with the peculiarity of vegetation cover of subtaiga and forest-steppe in the southeast of the West Siberian Plain and North-Minusinsk Basin. We give a general description of the vegetation and its varieties: South taiga spruce-pine-fir forests with birch, aspen and swamps; birch and aspen forests in combination with coniferous forests, meadows and swamps; birch and aspen forests with the inclusion of conifers – mainly spruce and fir, with meadow grass and swamps; meadow steppes, meadows with birch and aspen forests; herb-shrub and grassy pine and aspen-birch and aspen forests; mountain dark coniferous taiga; meadows combined with marshes, bushes and forests. The presence of a number of relict signs indicates that the formation of soil, changing the boundaries of vegetation zones and structure of the vegetation cover, is connected with the changing of climatic conditions in the post-glacial era. Traces of dry time are available in subtaiga and in the forest-steppe. It is noted that the forested areas near settlements are located on the hayfields, pastures and plowed fields among groves and woods, are presented by small-leaved birch and aspen stands. Forest has water-regulating value, but forms a complex configuration of fields and meadows, thus reducing the efficiency for the use of agricultural machinery. The article shows the relevance of the problem of deforestation and the possible risks of environmental changes if insufficient attention is paid to this negative process. Problems of reforestation are being raised.

А wild forest is 'filled' with defects (or gaps) of various kinds, such as glades, clearings, cuttings, forest roads. The models of dynamic processes in the forest, which are connected with the appearance and disappearance of vacancies in the horizontal forest structure are considered. Two types of the models that describe the processes of appearance and disappearance of such vacancies are presented. The conditions under which the existence of stable states with small number of vacancies is possible are discussed.

The kinetic model considers processes of appearance and disappearance of vacancies as stationary with constant values of the probabilities of the appearance and disappearance. It is shown that the kinetic model with independent intensities of transitions has no restrictions on the number of vacancies in the forest, which is not consistent with the field data.

The optimizing model of the weakly imperfect gas of vacancies assumes that the condition of an individual tree depends on its interaction with other trees and with vacancies. Vacancies themselves do not interact because they are rare and separated by vast distances. The model introduces an optimization function as the characteristic of the dieback risk of a stand, and it is assumed that the existing evolutionary processes select ecosystems with the density of vacancies at which the system has minimal loss risk. It is shown that the dieback risk of the trees in a stand is minimal if the number of vacancies in the stand is much less than the number of trees.

Substantial meanings of “sustainability” and “sustainable forest management” used in different ways were discussed in the article.

The aim of studies is to estimate physical (numeric, volumetric) parameters of age structures of stands, dynamics of changes in volumes of natural regeneration, to evaluate volumes of fallen trees focusing on their decomposition stages, and on the degree of damage caused by fungi of biotrophic complex in the course of trees aging, and to assess condition of trees in forests possessing sustainability characteristics.

Research objects and methods. The analysis was made for forests which meet the criteria of sustainability, and which dynamics fazes are close to the climax forests communities’ ones – i. e for virgin spruce forests of different ages of the following areas: Kandalaksha forestry (Murmansk region), Severodvinsk forestry (Arkhangelsk region), National Park “Yugyd-Va” (Republic of Komi, sub-zone of Northern taiga), and Central Forest biosphere reserve (sub-zone of Southern taiga). Silvicultural assessments of biogeocenoses, complete enumeration and inventory of trees, drilling at a root collar to estimate trees age, identification of location, type and development stage of rots and description of trees condition were conducted on the fixed test sites.

Experiment and discussions. Silvicultural characteristics of biogeocenoses of climax, demutational and digressional dynamic fazes are shown in the table. The graphic chart specifies indices of trees stands age structures, dynamics of changes in the volume of natural regeneration in accordance with its heights scale from 0,5 m up to 3,0 m and the ratio of those indices coherence (r = 0,67 when mr = 0,06 and t = 11,1). The chart also shows parameters of fallen trees volumes focusing on their decomposition stages, parameters of the damage caused by wood-destroying fungi of biotrophic complex to trees of different age generations as well as on parameters of trees conditions.

Conclusion. Physical parameters of structures for stable spruce communities are close to the specified above characteristics and could serve as markers when analyzing spruce forests structures of other structural characteristics and when confirming that they meet the parameters of stable forest communities.

In order to clarify some silvicultural issues concerning the different forest forms and different caring methods, it is necessary to know the dimensions of the tree crowns (length, cross-section, volume, lateral area). Methods for determining these elements have not yet been sufficiently developed. The object of our study was a relatively homogeneous isolated forest area, in which pine trees grow. The main objective of our work was to determine crown forms of Pinus sylvestris in various sizes and to estimate their volume. According to silvicultural zoning, the study area belonged to the Altai-Sayan mountain taiga region of the silvicultural province of pine and fir forests (Sisimsky District of mountain taiga fir and pine forests).

Studying the range of crown forms of Pinus sylvestris, it is possible to distinguish several groups of predominance of one or another form. In steps of 8 and 12 cm in thickness, the cylindrical form has the greatest prevalence, with a slanting cone being rare. The presence of this form can be explained by not yet closed canopy, with climatic factors having a favourable effect on crown development and absence of clear competition. It is difficult to identify the predominance of any one form in steps 28 and 32. In this case the form depends on stand completeness, availability of light and competition. Lack of light, high stand density and species competition contribute to the formation of different crown forms.

As a result of the performed work, it has been determined that it is not possible to compare the crowns with any particular geometric figure, as the crown habitus is diverse. This variation in thickness indicates that the pine crowns are very vulnerable to wind loads. It is not possible to propose one universal formula for determining the form of pine crowns, as volume errors are significant. The volume of pine crowns is recommended to be determined separately for large and small trees.

The results of a comparative study of evergreen coniferous species of Siberia (Picea obovata Ledeb., Pinus sibirica Du Tour., Pinus sylvestris L., Abis sibirica Ledeb.) are described in terms of low-temperature exotherms and endotherms during freezing to –80 ºС and thawing of 2-year-old needles carried out using differential scanning calorimetry (DSC). It has been established that the needles of the trees of the listed species, collected in early-mid-autumn, differ both in temperature of the beginning and end of water crystallization, and in temperature of the beginning of ice melting, the amount of released and absorbed heat, and the amount of bound water. Individual variability of the needles of the listed tree species was estimated in terms of the temperatures of the beginning, peaks, and end of water crystallization during its cooling, as well as the temperatures of the beginning, peak, and end of ice melting during heating. General character of changes in the DSC profiles of most of the samples when they are cooled to –80 ºС is noted. In the samples, 2 exothermic peaks were observed more often, than 1 or 3–5 peaks. Analysis of the data indicates a continuous rapid crystallization of water in 2–3 different tissues of needles at sample cooling rate 10 ºС min–1. Differences in heat absorption temperatures during ice melting in the samples, on the whole, are consistent with the noted differences in the temperatures of heat release during crystallization of solutions. A higher physiological frost resistance was found in the needles of Siberian spruce and Siberian fir, as well as Scots pine trees from Yakutia. The results obtained confirmed the possibility of using the DSC variant with a fast-cooling rate to assess the frost resistance of trees, which makes it possible to increase the sample size of trees.

Are investigated 35-years experimental plantations of pine (Pinus silvestris Ledeb) at 18 variants of densities in the southern taiga subzone (Krasnoyarsk Krai). The peculiarities of growth dynamics and productivity of dense-variety cenoses, starting from the moment of their planting, were considered. It has been proved that the density of planting cultures initially determines the individual scenario of the course of growth and development of cenoses in the process of formation. Density-dependent characteristics of changes in stocking, diameter and height of cultures are obtained. It is proved that with age, very dense cenoses lose priority in terms of productivity, and the optimal density of cultures gradually shifts to lower planting densities.

The results of studies about the growth and yield of dekapitation trees pine Siberian Cedar at plantation “LEP-1” in the Karaulny territory of the Training and Experimental Forestry SibSU are given. Trim crowns held at the 28-year-old in the biological age trees from 4 up to 10 interstitial site at a height of 1.7 to 2.8 m. Through 9 years trees were subjected to repeated delete 6–8 interstitial site of leading shoots. Control trees aged 50 years reached a height of 8.9 m. The average height of the cropped trees amounted to 7.9 m, which at 12.6 % lower than in control trees. Coefficient variability of cropped trees is higher than of the control trees. The diameter of the trunk control and cropped trees in a 50-year-old has no significant differences. After trimming crown trees are formed mainly by 1–2 leading the escape. Three leading escape was formed at 47 % of the trees, four – in 3 % of the trees. In 2017 g. bumps were formed on 34 % of control trees, 46 %-cropped trees.

The paper presents the results of the analysis of plant communities of Piedmont Dagestan with the participation species of the Red Book Juniperus excelsa subsp. polycarpos (C. Koch) Takht. The taxonomic and biomorphological structure of the flora was considered, a geographical analysis was carried out, endemic, relict and protected species identified in the Red Books of Russia and the Republic of Dagestan were identified.

239 species of higher plants belonging to 163 genus and 58 families have been identified, the spectrum of families (As-Po-Ro) characteristic of the xerophytic-steppe florocenotic complex of the Central European type has been determined. The biomorphological spectrum of juniper open woodlands of Piedmont Dagestan belongs to the hemicryptophyte-terophytic type, corresponding generally to the arid flora. The high proportion of relicts and endemics (21.3 and 21.5% of the total number of species, respectively) in the composition of juniper open woodlands indicates their relict nature, significant peculiar and role autochthonous processes in the formation of the juniper forests of Piedmont Dagestan.

Analysis of the structure of the flora of juniper open woodlands of Piedmont Dagestan shows its cross-border position at the junction of the boreal and ancient Mediterranean kingdom of the Holarctic, in the zone of contact of the Euro-Siberian and Iranian-Turanian regions, characteristic generally and for the Caucasus with a deeper and ancient connection with the Iranian-Turanian flora.

The results of the genetic diversity study of Siberian spruce growing in the regions of Siberia are presented. It was revealed that major share of genetic variability accounts for intra-population variation (93%). The distribution of the studied populations into 2 main clusters at genetic distance is apparent.

In forest valuation and forestry the considerable number of methods and receptions of assessment of a condition of dynamics of forest stands is used. One of them is application of the so-called complex estimated indicator having still the name “coefficient of tension of growth” which pays off as the relation of average height of a forest stand (N, l) to the cross-sectional area of an average tree in a forest stand (G, cm2) at the height of 1.3 m. The purpose of work was establishment of size of this criterion and features of its dynamics in normal and modal forest stands of a larch Siberian in Siberia. In work on the basis of materials of natural valuation 434 having manufactured and also the analysis of nine tables of the course of growth of normal and modal forest stands of a larch of the Siberian zelenomoshny group of types of the wood for various regions of Siberia, dynamics of average sizes of an indicator is established, assessment of degree of an oposredovannost of size of a complex estimated indicator is carried out by taxation characteristics of forest stands. The possibilities of use of this indicator for comparative characteristic of features of formation of forest stands in various forest vegetation conditions are considered.

From 1931 to 1991, timber processing enterprises and the pulp and paper mill of the city of Krasnoyarsk were supplied mostly by water in bag booms from the Sliznevsky raid and the raid of the Krasnoyarsk timber-handling plant (THP).

Wood on the Sliznevsky raid came from the river Mana through the loose wood line, excluding the exit of the forest of passing wood on the ship channel. Therefore, the bulk of the sinker wood was located at the bottom of a narrow strip along the right bank of the r. Yenisei, the width of which did not exceed 100 m. Wood flowing through the Mana River to the mall pipe lost part of its buoyancy margin when rafting directly along the Mana River, passing through the loose wood line, finding it in the pool, in the course of sorting works, forming bag booms. Therefore, part of it settled on the bottom of the Yenisei River in the loose wood line and in the waters of the enterprises operating at that time. The article provides an estimate of the amount of sunken wood on the Yenisei River in the area from the village of Ust-Mana to the city of Krasnoyarsk, obtained when performing full-scale surveys of the coastal water area of the Yenisei River at the site of the previously loose wood line. In accordance with the studies carried out in the coastal waters of the right bank of the Yenisei River, from 65 000 to 88 000 m3 of timber were flooded in the section from the mouth of the Mana River to the Krasnoyarsk THP site within the city of Krasnoyarsk. Studies assessing the quality of flooded wood show that existing stocks of flooded wood mass may be involved in industrial production. The involvement in the production of significant volumes of wood mass will not only provide economic benefits, but also a tangible environmental effect from cleaning the waters of the Yenisei coastal zone.

Genus Larix – one of the most common in the Russian far East representatives of the pine family. The conducted GIL showed that in the Khabarovsk territory the area occupied by Larix dahurica is 33.7 % of the total forest area, Kayanader larch is 0.2 %. In the far Eastern taiga forest area, larch forms mainly forest plantations, in the AmurPrimorsky coniferous-deciduous forest area, it is found almost everywhere with an admixture of birch or spruce. In General, the edge is marked by low quality Larix dahurica wood. Of the total number of trees accounted for – 3747666.7 thousand pieces. less than half (46.6 %) attributed to business trunks, 29.8 % – to poludelovym and 27.1 % – wood. Larix dahurica is one of the most studied tree species in the region. This led to the development of an extensive regulatory framework for this breed. The involvement of unsystematic experimental material indicated its low accuracy and, as a consequence, low accuracy of the developed standards. At the state inventory of the woods the basic taxation indicator – a stock of a stand define with the predetermined accuracy (2,5–5 %). Therefore, the accuracy of standards developed on the basis of these materials will be similar. According to the materials of the state inventory of forests, the interrelations of taxation indicators of Larix dahurica are studied. Regressions with the highest determination coefficients were selected for practical calculations. The justification of the known ratio 3/2, used to calculate the optimal number of barrels, is given. As an example, on the same experimental material, two tables of the growth course are constructed, in which the dynamics of the average values of taxation indicators is calculated according to different regression equations. Different regression had an impact on the dynamics of the stock of forest stands of Larix dahurica

The requirements for the chassis of the basic machine for mechanization of the process of harvesting and transportation of plant raw materials in the northern regions of the Krasnoyarsk Territory are given. The articulated caterpillar machine most fully meets the above requirements. The substantiate choice of articulated tracked vehicles based on comparative analysis with other types of vehicles in support, kinematic, dynamic indicators, when moving, turning, and operating loads in the running system. Various solutions are proposed the articulated caterpillar machine vehicles by imple-menting the block-modular principle, in which the layout of unified mass production units can be created a family of machines consisting of energy modules and technologi-cally active modules, with flexible technology and with the use of new concepts and technical solutions. The energy module of the machine can be created on the basis of existing wheeled tractors of agricultural purpose and cars. The trolley for the motor-transmission unit and the technological trolley can be made in the form of frame modules with various variants of the running system, for example, on pneumatic compactors and crawlet drive with rubber tracks. On the trolley can be installation the motortransmission blocks of various wheeled vehicles of different power, whereby it is possible to create a spectrum of standardized equipment of various technological purposes and in different capacities, capable of working in any conditions. The use of on-board chain drives, driving bridges of the automotive type of the front trolley, cardan gear and the rear driving bridge of the rear makes it possible to simplify the transmission of torque to the on leading asterisks caterpillars trolley. Turning of the articulated machine can be carried out by changing the angle between the longitudinal axes of the energy and technological trucks. The process is realized by means of differentials and brakes mechanisms installed on the half-axles of leading bridges.