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This work is devoted to the study of evapotranspiration in the landscape complexes of the northern macroslope of the Western Sayan. Article summarizes literature and authors’ data on evapotranspiration obtained at experimental watersheds in the basin of the river Kebezh, on one of which in the 70s, as an experiment, 50 % of the forest area in the watershed has been cut down. Calculations of the total evaporation of phytocenoses at the basin level has been made, taking into account the altitudinal zonality. To calculate evapotranspiration at the study sites, field data obtained as a result of silvicultural and geobotanical studies and hydrological observations were used. Based on interpretation of remote sensing images and the use of digital elevation model, classification of landscape-hydrological complexes for the basins of the Kebezh and Taigish rivers was carried out, for which the components of evapotranspiration were calculated. The results showed that evapotranspiration in the dark coniferous taiga of the Western Sayan is an important component of the water balance and a significant proportion is the unproductive consumption of moisture for the evaporation of precipitation intercepted by tree crowns. It has also been established that the structure of evapotranspiration changes along the altitudinal zones in accordance with the vertical differentiation of climatic parameters and vegetation productivity. Estimated evapotranspiration data for various landscape-hydrological complexes made it possible to an indirect estimates of their contribution to the formation of runoff in river basins. This study can serve as a theoretical guide for landscape hydrological studies in the temperate cool zone.

Due to the observed climatic shifts, the problem of an adequate assessment of the carbon depositing capacity of forests and its possible climate-related changes is being actualized. To achieve optimal plant productivity, a certain proportionality between its constituent organs must be ensured, which depends, among other things, on the relative amount of biomass in these organs. In contrast to the theories of metabolic scaling and adaptive mass distribution, the study performed is associated with a concept based on non-Gaussian distributions. Using published data on biomass of 4515 trees of forest-forming coniferous genera of Eurasia, a new concept of ranking biomass fractions based on a modified Zipf-Pareto model is presented. Since the stem and branches of the tree perform the same function in its architectonics, namely, the implementation of xylem and phloem transport and the maintenance of the assimilation apparatus of the tree in the canopy space, we combine these two components into one common block when ranking biomasses. Since the 1-year-old seedling has no branches, and the needles are attached directly to its stem (the axis of the initial sprout), combining the biomasses of the stem and branches into a single block allowed us to consider the dynamics of the distribution of biomasses in the plant in the total age range, from seedlings to mature trees. Having accepted the ranking of biomasses in the sequence: stem plus branches, roots and needles, we established a positive relationship of the biomass with its rank at the initial stage of plant growth. As the plant grows, the named positive relationship changes its sign and becomes negative one. The presented regularity is confirmed statistically at the level of p<0.999. The change of the sign of the coefficient of competition for a resource occurs in all the genera in a fairly narrow age range between 2 and 7 years.

The results of a study of seed productivity and sowing qualities of seeds on forest seed objects of the Siberian stone pine ( Pinus sibirica Du Tour) in the Pyzhinsky Forestry Compartment of the Turochaksky Forestry District of the Republic of Altai are discussed in the article. The objects of the studies were forest seed orchards of the first order and permanent forest seed plots of improved origin, created in 1980-1988 by seedlings of a plus trees on the area of 22.8 hectares. Evaluation of seed productivity and seed quality was carried out in the average-yield’s year by standard methods. The average seed yield was 31 kg/ha, varying by objects from 8 to 73, the size of the cones was 7.0 × 5.4 cm, varying from 4.5 × 4.0 to 9.0 × 6.0 cm. The main contribution to the variability of yield indicators is determined by the age, which at the time of the studies was 27-34 years. So far, the yield of seeds from cones and the viability of seeds are reduced somewhat in comparison with natural stands. The highest yield (73 kg/ha) and viability of seeds (87 %) is in the most mature forest seed orchard. Based on the dependence of the yield on age, a forecast was made that the forest seed orchard will achieve the natural Siberian stone pine forests of Altai’s seed productivity (150 kg/ha) to the age of 50. The least variable traits are the sizes of cones and seeds and their shape indices (variation coefficients are about 9-10 %). Intermediate and rather unstable reproduced on various objects are the coefficients of variation of seed viability (5-58 %). Obviously, this is due to differences in the efficiency of pollination due to different ages of stands. The greatest variability is typical for weight and counting traits - from 30 to 200 % or more.

The results of a study of the relationship between forest survey indicators and a condition indicators with the size of trees in diameter and their relative height are presented with the possible use of the latter in assessing the state of even-aged, high-density, pure composition pine forest stands of Zatyumenskiy ecological park in the city of Tyumen. It has been revealed, that 6-13 % of the total number of trees in the sample plots falls on the share of small-diameter trees. At the same time, the timber stock of such trees does not exceed 4 % of the total growing stock. Large-diameter trees account for 18-36 % of the total number of trees and 30-50 % of the total timber stock in the sample plots. In terms of indicators such as tree health and relative vitality, relative height and growth stress coefficient, small-diameter trees, in most cases, are characterized as severely weakened, dying and biologically unstable. At the same time, large and medium-sized trees are considered as healthy or weakened, but biologically stable. The average indicators of the general state of the tree stand are significantly negatively affected by the presence of small-diameter trees, in most cases, very weakened and dying. A general pattern of deterioration in the state of the tree stand with an increase in recreational impact has been revealed. It has been established that weakened trees with a relative height H/D < 100 are characterized by the smallest diameters, and their number and timber stock increase with an increase in recreational impact. Based on the results of the studies, a number of forestry measures have been proposed to increase the biological stability, recreational attractiveness and protective functions of the studied pine forests.

The study of the wood quality in the drained pine stand was carried out on the territory of the north taiga of Arkhangelsk Oblast, which belongs to the green zone of the city of Arkhangelsk and the Arctic zone of the Russian Federation. Repeated measurements of forest inventory parameters were carried out on 6 permanent sample plots affected by melioration since 1974 and reconstruction of the drainage network in 1990. Before drainage, a swampy pine stands of the V^b bonitet class grew on them. At present, medium-aged scots pine ( Pinus sylvestris L.) stands of shrubby-sphagnum forest type, IV bonitet class, grow on the drained area. For half of the plots, it is possible to recommend thinning according to the current Russian Rules of forest care (2020). Some of the trees meet the requirements for the aviation lumber wood quality. For a visual simultaneous analysis of the drainage network quality impact, the location of objects relative to the drainage network and the air temperature in abnormally hot years, diagrams of changes in the average indicators of the width of the annual increment and the wood density in the drained pine stands by year are constructed. Similar diagrams are constructed on the basis of measuring the model tree cores at different relative heights of the trunk. This analytical approach has been applied for the first time. It is suggested that in 10 years the inventory parameters of all facilities will meet the requirements for the thinning purpose, and the wood quality will increase on average, for which it is recommended to reconstruct the channels.

The results of studies on the adaptation of arctic bramble ( Rubus arcticus L.) plants of Astra and Sofia cultivars obtained by the clonal micropropagation method to non-sterile ex vitro conditions using the hydroponic method of cultivation are discussed in the article. The arctic bramble is a highly valuable species of forest berry plants in food and medicinal relations, rarely found and having a low yield in natural conditions. Adaptation to non-sterile ex vitro conditions is one of the limiting stages in clonal micropropagation. The survival rate of regenerated plants of arctic bramble of the studied cultivars in the conditions of a hydroponic system is 98 %, 1 month after planting in open ground - 69 %. Regenerated plants have stronger differences in morphometric parameters between clones within a cultivar than between cultivars. The arctic bramble planted in conglomerates formed shoots in the amount of 5.0 pcs. with an average length of 2.5 cm on the 20th day of adaptation. On the 45th day of arctic bramble plants after division into separate shoots had an average of 3.0 pcs. shoots with an average length of 8.3 cm. The arctic bramble plants of the Sofia cultivar have higher morphometric parameters of the above-ground and root systems compared to the Astra cultivar on the 45th day of cultivation in a hydroponic system: by the number of roots - by 30.3 %, by the total length of the roots - by 23 %, by the number of leaves - by 20 %, by the number of shoots - by 14 %, by the length of the shoots - by 10 %. The indicators of the development of the root system on a hydroponic installation depended on the varietal characteristics and the growing period. The arctic bramble plants have roots 10-20 cm long and shoot growths of 20-30 cm after 2 months of adaptation, which indicates its suitability for planting in open ground conditions.

Data on the interannual dynamics of the seasonal thawing depth in the dominant landscapes of typical tundra at the Marre-Sale geocryological station (western coast of the Yamal Peninsula) are presented. It is shown that drained landscapes have the maximum response to changes in climatic conditions, while wet and boggy landscapes are characterized by the reduced rates of increase in the active layer depth. The slow increase in the depth of seasonal thaw during the current climate warming is explained by the presence of an ice-rich horizon in the upper part of permafrost, thaw subsidence, and an increase in the height of the moss cover. The uneven growth of vegetation, primarily mosses, creates considerable contrasts in the spatial distribution of the active layer depth. For a regional assessment of the thawing depth, the use of its mean weighted value with due account for the share of each landscape in the entire landscape structure of the region is recommended.

Hydrochemical monitoring of inland waters makes it possible to obtain information about their state and to assess the influence of climatic factors on the regime of water reservoirs. In the recent decade, relevance of the research related to the impact of permafrost thaw on the state of small lakes in the Arctic has been growing. The influence of interannual fluctuations in air temperature and precipitation on the ionic composition of lakes has been statistically established for the contents of NO₂, SO₄, and NO₃ ions. Active thermodenudation on the shores of these lakes increases water mineralization levels by an average of 42.8 % and changes the concentrations of major ions Na, Ca, Mg, K, PO₄, and HCO₃.

A study of permafrost and groundwater conditions of the Mahatta Tukulan, Sakha Republic (Yakutia), where thick aquifer talik horizons are common, was carried out. During the first half of July 2021, the water discharge of the Mugur-Taryn Spring was 690 L/s, which is less compared to data from 1973-1974 (770-930 L/s). Current data confirm that the chemical composition of suprapermafrost and interpermafrost groundwater has been stable over the past several decades in the studied sand massifs. The chemical composition of these spring waters is calcium-magnesium bicarbonate, with mineralization of 13-50 mg/dm³. Using field observation data and results of remote sensing data processing, it was determined that the area of the sand massif with a vegetation cover has increased by approximately 18 % during the past 40-50 years. This has led to a decrease in soil temperature, a change in the water heat balance of the massif, and a reduction of water reserves of talik aquifers.

The article offers an analytical solution to the problem of operation of deep seasonal cooling devices (deep SCD) based on the assumption of quasi-stationary regime of soil freezing by the system evaporator. The case of application of the proposed solution for one of the design configurations of a deep SCD on thawed soils with different thermal conductivity under the weather conditions of Salekhard city is considered. We obtained the values of the radius of soil freezing around the evaporator tube as a function of depth at different time intervals of system operation. The present analytical model can be easily applied at the design stage to evaluate and optimize the design of the applied thermal stabilization system in particular geocryological zones for different thermophysical characteristics of soils, taking into account the aggregate state of water in them.