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The results of long-term experiments carried out on two stationary objects of forest plantations in 1976 and 1968 in different types of forest growing conditions of the Mari Trans-Volga region are presented. The plantations of the 1967, created in a dry forest, consisted only of pine Pinus L. and birch Betula L. trees in various proportions, and the second, created on loamy soils, is of three tree species (birch, spruce Picea A. Dietr. and pine). Pure pine plantations served as a control group. The productivity of the stand, its commodity composition and tax value were estimated by calculation in terms of the average diameter, height and number of trees according to our methodology. The relevance of research is driven by the need of improving measures to optimize the species composition of forests in order to preserve biological diversity, as well as reduce the frequency and intensity of fires. It is shown that in dry and fresh pine forests, pine-birch plantations demonstrate significantly worse stand productivity and especially tax value. Until the age of 10-15 years, the height of birch trees in them is higher than that of pines, but after 25-30 years, their position changes to the opposite. On sandy loam and loamy soils, birch suppresses from the composition of the stand not only light-loving pine, but even shade-tolerant spruce, significantly exceeding them in size. It is concluded that it is impractical to create mixed pine-birch and pine-spruce-birch crops in the conditions of the Mari Volga region due to the different demands of tree species on soil fertility, as well as differences in the speed of their growth and development. These plantations also do not fulfill the functions assigned to them for increasing the biological diversity and sustainability of the functioning of plantations, as well as to reduce their fire hazard.

Qualimetry of aboveground and underground biomass of trees is an integral part of studies of biological productivity and carbon depositing capacity of forest cover, necessary for the correct assessment of the carbon cycle in its spatial gradients and in relation to climate change. The great bulk of carbon is deposited in tree stems and largely depends on the basic density (BD) of wood and bark. The author’s database on the qualimetry of forest-forming species of Northern Eurasia is used in the work. About 3.450 model trees of 9 tree species (genera) were selected from it. The constructed mixed-effects models describing the dependences of the BD of wood and bark on their dendrometric indicators, geographical coordinates and species belonging of trees, revealed a 0.25% decrease in the BD of wood by 1 ° N. in the direction from south to north and 0.26 % decrease by 1 °E. in the direction from west to east. In the same gradients, the decrease in the BD of the stem bark is 0.55 % by 1 °N. and 0.28 % by 1 °E., respectively. The largest share of the explained variability of BD is accounted for by the species of trees - 74 % for wood and 87 % for bark, significantly less - by geographical location - 12 and 9 %, respectively, and the smallest share - by dendrometric indicators of trees 14 and 4 %, respectively. The ranking of species of equal-sized trees by BD value was performed, which showed that each species has a specific ratio of BD of wood and bark. This means that for a more correct assessment of the basic density and carbon deposition in wood and bark, it is necessary to process separately wood and bark of the disks removed from stems, and not the disks over bark as a whole.

Here we analyzed the data on the burning of the territory of the national park «Krasnoyarsk Stolby» annually recorded in the protected area and the buffer zone as part of long-term observations of natural processes. Information on fires was summarized starting from 1942 onwards and converted into the ArcGis database. A digital model of the fire history in the national park has been obtained, which includes 176 fire sites (610 tax. divisions), 40 (58 tax. divisions) of which are known by repeated fires. A retrospective analysis of the actual burning of forests in this territory for the period from 1942 to 2020 was carried out. The frequency of fires and burnout areas differ significantly for different functional zones of the national park, depending on the protection regime. The most frequently combustible (2.4 events per year) are sites with a recreational use regime, where the interval between fires not exceeding 2 years. The largest burned sites were in the strict strictly protected zone in 1956 and 2002. Ground fires of low and medium intensity became predominant over the entire period. In terms of area coverage, the most extensive fires occurred in the period from 1997 to 2006 with 1744 hectares covered by fires, including repeated fires in the same areas in different years. The joint analysis of the maps of the burning of the territory and the data on forest types showed that most fires for all considered period took place in stands where the dominant species was Scots pine Рinus sylvestris L. (59 %). The strictly protected zone of the national park is the least protected from major fires in the future, due to the high class of natural fire hazard in recent years because of the massive drying up of conifer stands (mainly fir) and a high degree of accumulation of forest fuel due to the long absence of fires in the protected area as a whole.

The woody and shrubby plants species composition and vital status at the territory of Krasnoyarsk Central Park were studied. The purpose of the work is to determine the tree and shrub species composition at the territory of the Central Park, to assess their vital status, to study the arboriflora structure and biodiversity, to identify dominant and single species, to give recommendations for improving the species composition and plantings quality. The studies were carried out in August 2021. The assessment of the species diversity, vital and sanitary condition of the park’s tree and shrub vegetation was carried out by the method of a complete enumeration of trees. The planting vital index determination was carried out using the generally accepted method of visual assessment of tree and shrub vegetation. It has been established that the Central Park arboriflora is represented by 86 species of plants, including: 39 species of trees, 46 species of shrubs and 1 species of vines. Arboriflora consists of 4470 plant (4133 trees, 337 shrubs), growing in the alley cropping, group planting, solitaires, boskets (total length 582 m) as well as hedge grow (50 m). The plantings vitality index is 1.99, which corresponds to a weakened or slightly damaged stands. The arboriflora structure was determined, its features were identified. The species that make the main contribution were identified. The most stable and weakened species of the park’s arboriflora were identified. Recommendations to stand developing of Krasnoyarsk Central Park were formulated based on the obtained results. It is advisable to apply park reconstruction proposals for urban spaces landscaping in similar environmental conditions.

The article is devoted to discussing problem of reducing numbers of the dark European honeybee Apis mellifera mellifera L. in the natural and historical habitats. By analyzing changes in forest legislation and administrative policies on the territory of the European part of contemporary Russia, it is established that one of the main causes of the identified problem is lack of housing for migrating bee swarms due to the extremely insufficient number of old-growth trees with suitable for habitat hollows. The aim of the work is to justify the creation of network of specially protected natural area (OOPTs) - of botanical natural monuments and entomological reserves of regional importance as organizational measures for protection, guarding and recovery of the dark European honeybee populations. The key elements of the OOPTs are proposed to make communities of insect and plants that are in protocooperation with each other - trees, in the hollows of which live colonies of dark European honeybee. With the purpose of reducing the probability of breaking the trunk with large hollows, the system of care for trees is presented, which is based on the reduction of the windage for the crown and its stabilization: the reducing tree height, the increase in laciness crown, the formation of a symmetrical crown, installation of tree crowns stabilization and protection system against breakdowns. Creation of OOPTs aimed at conservation and restoration of the Dark European Honeybee populations will contribute to the conservation and increase of biodiversity, the organization of systematic study of the dark European honeybee populations and other pollinating insects, the formation of a network of environmental routes with upbringing, enlightenment, educational and scientific character, the disclosure of the recreational potential of the territory, the employment of the local population by creating additional jobs

Deforestation and forest degradation in the forest-steppe zone is one of the most pressing issues in the world, involving territory of southern boreal forests in Northern Mongolia. The changes in forest cover between 1999 and 2016 and driving factors to deforestation and forest degradation in the Khustai nuruu mountains of the Northern Mongolia were analyzed. Forest monitoring was carried out in mature and over-mature flat-leaved birch Betula platyphilla Sukacz. forests with an admixture of aspen Populus tremula L. using the combined method of remote sensing and ground based field measurements. We found an accelerated deforestation trend between 2006 and 2009, which amounted to 463 ha (23.2 %) since deforestation in the Khustai nuruu mountains was started. Overall 17-year forest monitoring revealed that a total of 675 ha of forests were completely converted to non-forest area. As urgent measures to mitigate the effects and limit rapid deforestation in study area, it is recommended to improve the sustainable forest management via establishing optimum head of livestock and wild animals, strengthening prevention and control measures against pests, and reforestation on deforested areas using seedling of native tree species taken from forest nurseries in the region.

This article deals with the hygroscopic properties of the coniferous bark species in Siberia. Isotherms of moisture sorption in the bark of the Siberian larch Larix sibirica Ledeb., the Scotch pine Pinus sylvestris L. and the Siberian fir Abies sibirica Ledeb., when the relative vapor pressure changes from 0.1 to 0.8 at a temperature of (20.0 ± 1.5) °C practically coincided. Therefore, to analyze the sorption properties of the system bark-water vapor within the framework of the Brunauer-Emmet-Teller (BET), Guggenheim-Andersen-de Boer (GAB), Frenkel-Holsey-Hill (FHH), Zimm-Lundberg (ZL), Flory-Huggins (FH), and the theory of volume filling of micropores (MVF) used for «generalized isotherm» that approximates experimental data. The isotherms of moisture sorption by bark were used to quantify the most important hygroscopic characteristics. We used BET and GAB to calculate monolayer capacity ( u _m), specific inner surface area ( S _sp) and ZL equation to find water vapor content and relative pressure when water clusters start to form in the bark samples; FHH, FH model and MVF theory to obtain fractal dimension of «sorption surface», sorbent-sorbate interaction parameter and characteristic sorption energy (Е_с), respectively. Based on the precision methods of thermal analysis - thermogravimetry (TG), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC), a fractional picture of thermal desorption of bound water and energy spent on its removal when heating samples at a constant rate. The values of u _m, S _sp indicate differences between these values obtained as a result BET models and the average value of the characteristic sorption energy E _с (MVF) indicates the absence or very small internal mechanical stresses in the cortex. From the analysis of the rate of nonisothermal drying according to the fourth derivative of the DTG circuit with respect to temperature, differences in the temperature ranges and thethermal desorption intensity of bound moisture by samples of bark of the Siberian larch, Scotch pine, and the Siberian fir were established; the heat of thermal desorption of bound water was 38.1, 38.0 and 45.6 kJ/mol Н₂О accordingly.

In the context of intensive replacement of natural forests by plantations, it is important to know how this replacement will affect the productivity of forests and their ability to mitigate the effects of climate change. The aim of our study was to establish: (1) how the ratio of biomass and volume of tree stems of two-needled pines (subgenus Pinus L.) of natural and artificial origin changes in temperature and precipitation gradients in Eurasia and (2) what contribution to the explanation of the variability of stem biomass is made by the tree’s forest inventory indices (stem age, diameter and volume), the origin of a stand (natural or artificial) and climatic factors (temperature and precipitation). To achieve this goal, a database of harvest data on the biomass of pine stems in the amount of 975 and 508 in natural and planted stands respectively, was formed. A positive relationship between the stem biomass and the average January temperature in conditions of sufficient moisture and its absence in dry conditions was established. The positive relation of stem biomass to precipitation in cold regions disappears as the transition to warm ones takes place. The stem biomass at the age of maturity in plantations is 15 % higher than in natural stands, and in young stands, on the contrary, it is less by 4 %. The contribution of inventory indices, the origin of stands and climatic factors to the explanation of stem biomass variability was 72, 10 and 18 %, respectively. The results obtained, tested on other tree species, can be useful in selecting tree species that are most tolerant to climate change.

To date, various aspects of the formation of spruce forests as a result of felling of small-leaved stands with the preservation of the preliminary generation of spruce Picea A. Dietr. have been studied. One that is poorly studied is the question of the development and growth of spruce in connection with the parcel structure of the stands after such felling. The aim of this work is to study formation and growth of spruce forests in parcel structures with the same spruce density after felling a birch forest, but at different stages of age development. The studies were carried out in the sub-zone of the southern taiga (Rybinsk District of the Yaroslavl Oblast) at the Northern Experimental Station of the Institute of Forest Science, Russian Academy of Sciences. The study object is forest stand formed after cutting a 55-year-old birch forest. The felling was carried out using the technology of narrow strips with preservation of the preliminary generation of spruce. The analysis is based on the data of 20 years of observations on permanent sample plots in two groups of parcels: spruce in the young stand stage, spruce in the pole stand stage. The density of spruce in the groups of parcels after birch Betula L. felling is, respectively, 4.53 and 4.58 thousand trees per ha, and the average age is 25 and 33 years, respectively. The response of spruce to birch felling has been observed already in the first ten years. In the considered groups of parcels, the condition of the spruce improves and the growth of trees increases. In the poles, the growth increases more intensively than in the young. The timber stock of the upper layer (trees above 4 m per year of felling) in the first layer increases by almost 30, in the second - by 100 m³. In the pole stand, productivity of the stand increases from class V to class IV bonitet. In the second decade, the state of the population in young trees deteriorates as a result of increased intraspecific competition (the proportion of normal trees decreases from 55 to 40 %). In the pole, the opposite process was observed - the proportion of normal trees increased from 60 to 80 %. During this period, the growth of the wood stock in young stands was more intensive than in the pole ones. However, the wood stock in spruce forest, formed from the perch, reached almost 300 m³ per ha 20 years after felling. In spruce forest, formed from the young stand, wood stock was almost 3 times less. The bonitet of the perch has reached III, the young - IV class. When felling birch forests with preservation of the undergrowth and thin spruce for the fastest recovery of spruce stands, birch forests should be considered the most promising, under the canopy of which the preliminary generation is represented by a spruce pole stand 40 years old. Such stands should be assigned to the felling first.

Lichen-green-moss pine forests represented by Scotch pine Pinus sylvestris L. of the III-IV age classes were studied under conditions of various modes of aerial technogenic environmental pollution in the central part of the Kola Peninsula. It is established that the current trends in the formation of secondary pine forests in deforestation and burning in the background areas are due to natural processes and intra-population relationships. Aerial technogenic pollution of SO₂ with heavy metals (Ni, Cu, Co, etc.) is the main cause of damage, weakening and even destruction of pine forests. The first sign of deviation from the norm of the state of scots pine is the dechromation of needles. The area of the affected surface of the needles with chlorosis and necrosis can reach 75 % or more. Premature fall of damaged needles is the reason for the reduction of its life expectancy on trees to 2-3 years in the area of intensive pollution in comparison with 6-7 years in the background stands. Atmospheric pollution suppresses growth processes in Scotch pine: up to 40-70 % increase in the height of the central shoots and 30 % or more increase in diameter in comparison with undisturbed communities. Under the influence of pollutants, the vital structure of medium-aged pine forests of lichen-green moss significantly deteriorates. Currently observed improvement of the pine forests in the areas of industrial air pollution on the Kola Peninsula (reduction of damage to the needles and increase its lifespan in trees, the intensification of the growth processes, improving the living condition of individual trees and forest stands) indicate a positive response of Pinus sylvestris at reducing aerial technogenic load.