Home – Home – Jornals – Siberian Journal of Forest Science 2019 number 5

Unsaturated absorption coefficients in pure CO₂ and binary mixtures of CO₂ with buffer gases M _j (He, Ar, Kr, Xe, N₂, O₂, CO, N₂O, ¹³C¹⁶O₂) were measured at the central frequencies of the R (8), R (22), R (34), P (8), P (22), and P (36) CO₂ spectral lines of the 10⁰0-00⁰1 transition at 300-700 K with a tunable CO₂ laser. A technique is described and the coefficients of self-broadening and broadening of CO₂ spectral lines by a buffer gas M _j are calculated. It is shown that the efficiency of CO₂ interaction with diatomic and triatomic molecules is determined by the electric moment; in the case of inert gases, the mass factor plays the major role. It is ascertained that the temperature dependences of the collisional broadening of CO₂ spectral lines can be highly accurate approximated by power functions with two different exponents.

The effect of collisional line broadening on the accuracy of tropospheric (0-11 km) temperature retrievals from pure rotational Raman lidar raw signals is estimated via numerical simulation. The simulation was performed for three sets of spectral filters with different passbands in a lidar receiving system. A narrow-linewidth laser with a wavelength of 532 nm was considered as a lidar transmitter. A comparative analysis of temperature retrieval errors (calibration errors) produced by using nine calibration functions is presented. The calibration function retrieving tropospheric temperature with the least errors is determined for each set of filters.

Second harmonic generation (SHG) in a nonlinear uniaxial crystal is theoretically studied. The main attention is paid to the estimation of the wave detuning effect on the SHG efficiency. The results presented confirm a strong dependence of the optimal value of wave detuning on the laser radiation power and a way of its focusing in a nonlinear crystal. A quite rapid algorithm is suggested for the numerical solution of the wave detuning optimization problem. The applicability of this algorithm to the analysis of highly efficient SHG is shown, including situations where the nonlinear conversion efficiency attains its maximum.

A method for estimating the intensity of the structural characteristic of the fluctuations of the refractive index C_n² from the data of a two-channel turbulent aerosol lidar operating on the effect of backscattering enhancement (BSE) is shown. It is proposed to use the Vorob'ev approximation, which for the case of homogeneous turbulence determines the dependence of C_n² on the ratio of echoes. The basis for this was experimental data, from which it follows that the BSE effect occurs in a relatively small area of space near the scattering volume. The results of sounding along a horizontal path are presented.

At present, only one classical technique accounting refraction during periods of undisturbed images allows one to largely compensate the influence of refraction on the results of geodetic measurements. However, these periods are very short, and their limits are extremely difficult to estimate. Therefore, despite many years of effort, the problem of accounting for refraction in geodetic measurements has not received a satisfactory practical solution. According to the studies of the turbulent method, the accuracy of the refraction determination corresponds to the instrumental accuracy of the device used, even in conditions of unstable temperature stratification of the atmosphere, when significant fluctuations of the angle of arrival are observed.

Variations in the sunlight duration (SLD) in Tomsk are analyzed for the period from 1961 to 2018 and separately for 1961-1990 and 1981-2010. Data on clouds and total solar radiation obtained at the TOR-station of IAO SB RAS in 1996-2018 are used. The actual long-term monthly mean SLD ranges from 44 hours in December to 317 hours in June-July. The analysis of the long-term variation in SLD shows its increase from 1961 to 1989 and its decrease starting from 1999 caused by an increase in the lower cloud amount and high frequency of continuous clouds. SLD in Tomsk in the modern period has increased relative to the historical period. Regression equations between SLD and the total solar radiation ( Q ) are derived.

In September 2002, the sudden stratospheric warming (SSW) was observed over the Antarctic as a result of the polar vortex splitting. The unusually early breakdown of the Antarctic polar vortex in spring 2002 was caused by the increased activity of vertically propagating planetary waves. The dynamics of the south polar vortex during SSW of 2002 is investigated. An unusual temperature decrease in the lower subtropical stratosphere, which contributed to a decrease in the stratospheric meridional temperature gradient is considered a possible cause of the weakening of the polar vortex, which preceded its splitting under the influence of planetary waves.

Zonal averaged fields of seasonal and long-term variability of the total ozone content (TOC), including polar regions, are investigated. It is shown that the long-term variability of all these series (with a spatial resolution of 3° latitude) is reduced to a parametric resonance with the lowest of the tidal oscillation frequencies (period of 18.6 years). After excluding this effect, series trends for all latitudinal zones become vanishingly small (having different signs) and statistically insignificant. The results are completely incompatible with the anthropogenic version of ozone depletion. It is stated that the phenomenon of parametric resonance is also observed in the lithosphere as applied to global tectonic activity.

We are studying the statistical relationships between the atmospheric column black carbon (BC) and the surface albedo ( A ) based on MERRA-2 reanalysis data for four test areas near the Arctic coast of Russia in April 2010-2016. The analysis also includes atmospheric meteorological parameters from the WATCH website data: air temperature and amounts of liquid and solid precipitation. The statistical analysis has been carried out for daily average values. An increase in the air temperature is accompanied by a decrease in the surface albedo everywhere, both on a monthly scale and in daily variations. Snowfalls increase the surface albedo also everywhere. Reliable negative correlations between BC and A in April were found only on the Gydan Peninsula. Some years (different for different areas) with good correlations between day-to-day variations in A and BC values within a month, also with negative coefficients, were revealed. We estimated possible changes in albedo values, as well as in albedo radiative forcing due to variations in different parameters.

The content and evolution of brown carbon (BrC) in biomass burning smokes from Siberian forest fires were analyzed using measurements of the absorption aerosol optical thickness at three AERONET stations situated in Tomsk (in Siberia), Zvenigorod (near Moscow), and Yekaterinburg (at the Ural). The analysis resulted in estimates of the relative contribution of BrC in fine aerosol particles to the absorption of solar radiation at a wavelength of 440 nm (h_BrC), in particular, for an anomalous episode of the long-range transport of biomass burning smoke from Siberia into the European part of Russia in summer 2016. A considerable fraction of BrC is found in smoke aerosol over Tomsk and Zvenigorod (where h_BrC is estimated to be about 15 and 18% on average), while the estimates of h_BrC for Yekaterinburg are found to be insignificant. The analysis also revealed a decrease in h_BrC in the process of aerosol aging under the illuminated conditions on the time scale of about 30 h. At the same time, the measurements in Zvenigorod indicate an increase in the absorption properties of the organic fraction of biomass burning aerosol after much longer atmospheric evolution.

We show that snow from the ice surface of lakes in oligotrophic bogs is suitable for monitoring the deposition of "long-distant" aerosol. Based on the concentration of impurities in snow samples from the plains of Baraba and Vasyugan, we estimated the background of winter deposition of aerosol substances in southeast of Western Siberia. It was found that the deposition of aerosol particles per day is about 7 mg/m², including 3.1 mg/m² in the form of solid particles. Winter deposition of particulate matter does not exceed 10% of annual deposition; therefore, it has almost no effect on sedimentation. The mineral substance prevails in solid impurities of snow, the average ash content is 65%. The background mineralization of snow water from the ice surface of oligotrophic bog lakes in the southeast of Western Siberia is close to the global background of precipitation mineralization.

Specifications of domestic and foreign shearers are given. The problem is formulated for optimizing web width of a shearer by the maximum capacity criterion with regard to geological and technology factors. The analytical solution is obtained for the problem using the approximating linear functions of the sloughing factor and the web width. The influences of the optimal web width of shearer are analyzed, and the related recommendations are made. The extremal curve of methane relase from broken coal is shown, and the allowable capacity of face by the gas criterion is tested in longwall 5214-1 in the Yalevky Mine of the Kuznetsk Coal Basin.

Layouts of reloading points in the cyclical-and-continuous technology for deep-level surface mining are analyzed. The innovative structure of a reloading point involving dump trucks drivethrough passing has been proposed; the structure will make it possible to increase reloading point productivity, cut the costs for rock mass extraction, and reduce the time of motor transport maneuvering. Dependence of general funds saving for overburden rock extraction upon the open pit depth while constructing a reloading point with the drivethrough passing comparing to a dead-end unloading of various-capacity dump trucks has been determined.

The classification of the methods available for diagnostic of mining machinery mounting groups with roller bearings is considered with indicated advantages and disadvantages. The model is constructed to describe formation of shock pulses in roller bearings when different defects are generated in them. This model is suitable for the availability monitoring of the machinery mounting groups. The applicability of wavelet transforms instead of the standard fast Fourier transform to random processes and vibro-acoustic signals is tested for the detection of defects in manufacture and operation of mining machines.

Sawing of natural stones with diamond-impregnated circular saws is extensively implemented in stone processing plants in variety of applications that include sawing, cutting, splitting and trimming. Hence, thecost of diamond saws and energy have become important input in terms of estimating the hourly areal slab productions (HASPs) from the standpoint of effective cost analyses,feasible and sustainable designing of stone processing plantsprior to reaching a decision forthe investment. This study aimed at estimating the HASPs of the machines with circular diamond saws during the dimensioning of marble blocks quarried in Mugla (Turkey) Region. Thus, the models were generated to estimate the HASPs by artificial neural networks (ANN) and regression method (RM), based on Shore and Schmidt hardness values of rocks. Also, HASPs were acquired through in-plant measurements in order to justify the HASPs estimated by ANN and RM models. The analyses of the models generated using ANN proved to yield very strong consistencies with HASPs measured in the plants. Hence, the HASPs canbe estimated reliably by the ANN modelswhich also may be considered as a tool in designing ofnatural stone processing plants based on rock surface hardness.

The influence of non-ionic compounds in combination with sodium oleate on the contrast behavior of flotation response of calcium minerals is investigated theoretically and experimentally. The flotation and adsorption analyses are carried out with monomineral fractions of calcite and scheelite, while the flotation process analysis is conducted with an ore material screened into size grades of - 44 and - 15 μm. The process conditions of the highest difference in adsorption of oleate and contrast in extraction of scheelite and calcite are found. the conditions of the maximum depression of calcite in the rougher flotation circuit are determined.

The influence of nitric, sulfuric and chlorohydric acids on the morphology, composition of elements, structural and chemical transformation of mineral surface and leaching of eudialyte concentrate is studied using a set of the modern analytical techniques. Specific features are revealed in the nature and degree of eudialyte decomposition under the influence of different acids. These features affect the intensity of removal of basic cations of Al, Na, Ca, Mg, K, Ti, Mn, Fe, Sr and Zr from the mineral surface. The behavior and regular patterns in the formation of silica gel and secondary phases during dissolution of eudialyte concentrates are examined. Sulfuric acid, which ensures the highest extraction of Zr and rare earth metals in pregnant solution, contributes to maximum formation of silica gel and considerable quantity of gypsum and insoluble sulfates, which results in high loss of Zr and rare earth metals. The use of nitric and chlorohydric acids reduces the loss of Zr and rare earth metals by 2-5 times.

The theoretical and experimental substantiation of the behavior of ferrous sphalerite in magnetic separation is given in terms of the Gorevka deposit ore. In sphalerite of this deposit, the content of isomorphous iron ranges as 4-9%. The Mössbauer spectroscopy showed the singlet and two doublet lines of iron, demonstrating separate arrays of iron atoms in sphalerite lattice, with formation of Fe-Fe pairs and clusters of three or more iron atoms. It is found that distribution of iron in sphalerite into three forms coincides for magnetic and nonmagnetic products of zinc concentrate separation. It is determined that magnetic separation undivides sphalerite grains by the isomorphous iron content but is governed by the genetic features of the deposit formation-association of sphalerite with magnetic minerals (pyrrhotine and siderite) and the absence of such associations in galenite.

The article presents the research findings obtained in deep integrated processing of rebellious high-potassium aluminum silicates from the Kalyum deposit within the Synnyr alkaline massif-synnerite-with production of alumina as well as potassium and magnesium sulfates. The introduction of magnesium-bearing mineral-dolomite-as an additive at the stage of thermochemical decomposition of the acid-resistant minerals in the initial raw material (K-feldspar group) provides improved efficiency of the processes due to cheapening of baking, increased marketable production and reduced solid waste. It is found that leaching of activated synnerite by 60% sulfuric acid promotes deposition of the silicon component as amorphous silica, which facilitates the further processing of pregnant potassium-, magnesium- and aluminium-bearing sulfuric acid solutions with marketable production.

The modeling procedure is developed to describe heat-exchange processes in outdoor summer storage piles of frozen coal produced in winter. This procedure takes into account thermophysical properties of coal and the pile bottom soil, pile structure, climatic factors and presence of a heat-insulating coating over the pile. In terms of central Yakutia, it is shown that maximum transition of coal from frozen state (piling in January-Marhc) top thawed condition at the pile height more than 5 m will make 25-35% by the end of the warm season (beginning of October). Application of simple and available heat-insulating materials can reduce thawing intensity by up to 2 times. Natural cold weakens the aggravating effect of oxidizing processes on coal quality in long-term storage of coal and its shipment to remote and hard-to-reach places.

The geophysical investigations are carried out at the Kangalass open pit coal mine using the round penetrating radar and electrical tomography. The main frost effects in rock mass and in water retaining dam are described. The investigation procedure is developed, and the wave fields are characterized. The GPR surveys aimed to reveal water invasion zones in a rock block to be blasted and to trace dynamics of a seasonal thawing layer are presented. The integrated analysis of GPR and electrotomography data is performed tod determine adverse freeze-and-thaw processes at the dam bottom. Applicability of GPR in prediction of unfavorable freeze-and-thaw activities is demonstrated.

The aim of the research is to verify the association with sudden cardiac death (SCD) of single nucleotide polymorphisms rs7172856 and rs61999948, identified as new molecular genetic markers of SCD in the own genome-wide pooled allelotyping. Material and methods. Case-control study. The SCD group is formed using the criteria of the European Society of Cardiology from the DNA bank of suddenly deceased residents of the Oktyabrsky district of Novosibirsk (n = 437, average age - 53.1±9.0 years, men - 73.5 %, women - 26.5 %) The control group (n = 405, average age 53.2±9.2 years, men - 70.0 %, women - 30.0 %) is formed from the DNA bank of participants of MONICA and HAPIEE projects. DNA was isolated by phenol-chloroform extraction from myocardial tissue in the SCD group and venous blood in the control group. Genotyping was performed by the PCR-RFLP method. Results. No statistical significance was found in allele and genotype frequencies of rs7172856 between groups, even in separating in sex and age (p > 0.05). The proportion of male carriers of the TT genotype rs61999948 in the SCD group (6.3 %) is statistically significantly less than the proportion of male carriers of the TT genotype rs61999948 in the control group (12.6 %) (OR = 0.47, 95 % CI 0.26-0.85, p = 0.011). The identified significance is reserved in the group under 50 years old (p = 0.007) and in the group of men under 50 years old (p = 0.002). The proportion of carriers of the CC genotype rs61999948 is statistically significantly higher in the SCD group (59.0 %) compared with the control group (42.5 %) (OR = 1.94, 95 % CI 1.21-3.12, p = 0.006) for people under 50 years old. The identified association of the CC genotype with the SCD is reserved in the group of men under 50 years old (p = 0.001). Conclusions. Single nucleotide polymorphism rs7172856 is not associated with SCD. The TT genotype of the single nucleotide polymorphism rs61999948 is associated with a protective effect against SCD and the CC genotype of rs61999948 is associated with an increased risk of SCD for men under 50 years old.

Objective of the study was to assess hypertension-mediated organ condition in young people with high normal blood pressure (HNBP) and with hypertension. Material and methods. The study included 112 patients with HNBP or hypertension, aged 25-44. The glomerular filtration rate (eGFR) was estimated according to the CKD-EPI formula for serum creatinine (eGFRcre) and cystatin C content. Microalbuminuria was established in a daily urine sample. Patients underwent echocardiography and dopplerography examination, duplex scanning of the brachiocephalic arteries. Results. eGFRCre in the range of 89-60 ml/min/1.73 m2 was observed in 37.1 % patients. There were no cases of a decrease eGFRCre less than 60 ml/min/1.73 m2. Renal hyperfiltration (eGFRcre) was detected in 10.3 % examined persons. eGFR by cystatin C content allowed to determine 23 % (p = 0.02) more cases of decreased renal function within 89-60 ml/min/1.73 m2, than eGFRcre. Also, patients with eGFR less than 60 ml/min/1,73 m2 were identified. Renal hyperfiltration was found to be 2 times more (p = 0.002) in patients with HNBP than in patients with hypertension, and frequency of decreasing eGFR below 60 ml/min/1.73 m2 was 11 % less (p <0.050). Microalbuminuria more than 30 mg/day was detected only in patients with hypertension. It was found concentric remodeling was more common in patients with hypertension (p = 0.02), a concentric type of left ventricular hypertrophy was detected only in patients with hypertension, patients did not differ in the frequency of eccentric left ventricular hypertrophy. Patients with HNBP and arterial hypertension had a comparable frequency of increasing arterial thickness. Conclusion. Young patients with high normal blood pressure have signs of organ damage, often hyperfiltration and an increase in the thickness of arteries. Revealed changes indicate the need to identify this category of people and develop preventive and/or therapeutic practices.

The goal of the study was to analyze copy number variation (CNV) in the GBP3 gene between white blood cells and atherosclerotic plaques of patients with carotid atherosclerosis. The material was both blood samples and atherosclerotic plaques obtained from the same patients with carotid atherosclerosis (n = 94). Assessment of CNV was performed using digital droplet PCR. As a result, it was shown that among 94 patients with carotid atherosclerosis, the CNV frequency was 44 % in the GBP3 gene in leukocytes. Deletion was detected in 5 (5.3 %) patients, and loss in 36 (38.3 %) patients. The gain was identified in one patient. Somatic mosaicism was found in 12 (13 %) of patients, comparing DNA samples of atherosclerotic plaque tissue and white blood cells from the same patients. Mosaic copy number losses predominantly were detected in white blood cells, in contrast mosaic copy number gains were identified in atherosclerotic plaques. Somatic mosaicism of the GBP3 gene is widespread in atherosclerosis. Different ratio of mosaic clones carrying certain type of CNV in GBP3 gene is presented.

Objective of the study was assessment of nutrition of adolescents in Novosibirsk as a whole and in groups with normal weight and overweight. Material and methods. In April-May 2019, a cross-sectional population survey was conducted on a random representative sample of schoolchildren aged 14-18 years of both sexes, 612 people were examined: 249 boys (40.9 %), 360 girls (59.1 %). Diet recall was taken in 537 persons. The survey program included a standard questionnaire, anthropometry, examination of blood lipids, and an assessment of diet using 24-hour dietary recall (537 persons). Results. Disturbances in the structure of nutrition were revealed both in the studied sample of adolescents in general, and in the group of boys and girls with overweight and obesity. Quotas of fat energy in general, saturated fatty acids, easily digestible sugars exceed recommended levels. The fiber content was below the recommended level by more than 2 times. The prevalence of overweight and obesity among adolescents in Novosibirsk was 21.1 % in boys and 14.4 % in girls. According to the main indicators of the nutritional value of the diet, differences between groups of adolescents of both sexes with underweight, normal, overweight and obesity have not been established. Conclusions. The results show that both adolescents with overweight and obesity, as well as with normal indicators of physical development, need to optimize nutrition.

Aim of the study was to evaluate the prevalence of overweight and obesity among adolescents and to identify the features of dyslipidemia in excessive weight. Materials and methods. In 2019 a cross-sectional population survey of a random representative sample of schoolchildren aged 14-18 (612 persons, 249 boys (40.9 %). 363 girls (59.1 %)) was conducted. The program included standard questionnaire, anthropometry, and determination of blood lipids. The prevalence of overweight and obesity among adolescents in Novosibirsk in 2019 was 17.5 %, among boys - 22.1 % (overweight - 16.8 %, obesity - 3.6 %, extreme obesity - 1.7 %) and 14.4% among girls (overweight - 11.9 %, obesity - 1.9 %, extreme obesity - 0.6 %). Underweight was more often recorded among girls, overweight and obesity - among boys. In boys with overweight and obesity higher prevalence of hypertriglyceridemia, hyper-low-density lipoprotein (LDL)-cholesterolemia, hypo-high-density lipoprotein-cholesterolemia were detected than in the group with normal weight. In girls with overweight and obesity prevalence of hyper-LDL-cholesterolemia was significantly more often than in girls with normal weight. Conclusion. In boys, overweight and obesity were more often recorded, and their lipid profile had more atherogenic properties than in girls.

The purpose of this review is to inform healthcare professionals that the combination of several risk factors (RF) has a serious effect on the progression of atherosclerosis, the development of cardiovascular (CV) diseases and death in people with type 2 diabetes (T2DM). Each of the factors, as a rule, enhances the effect of the other, and if the patient has several of them, then combining them with diabetes is deadly for him. Only an integrated approach to the treatment and effects on RF can improve the prognosis for patients with type 2 diabetes. It is shown that in the treatment of modern classes of hypoglycemic drugs, complex metabolic control is important. Prevention of CV disease is, therefore, a goal of treatment of T2DM as important as glycemic control. The use of drugs with proven cardiovascular benefits is recommended as part of of glucose-lowering therapy. The data of international studies of preparations of a sodium-glucose co-transporter 2 (SGLT2) inhibitor and glucagon-like peptide 1 receptor agonists (GLP-1 RAs) various links in the pathogenesis of complications of diabetes mellitus (DM) reduce the risk of CV events. Based on the original trial results healthcare professionals should the use of antidiabetic drugs that have been proven to reduce cardiovascular events and mortality.

The literature review highlights the results of foreign and Russian studies of recent years, devoted to the study of biochemical factors and potential biomarkers of calcification of the vascular wall, as well as atherosclerotic plaques of the coronary and carotid arteries. The results of the studies allow to clarify and to supplement the known mechanisms of calcification of the vascular wall. To date, the four most studied biomarkers of vascular calcification are most studied - osteoprotegerin, osteopontin, osteonectin and osteocalcin.

Prevention of adult diseases from childhood is one of the most important goals in modern medicine. This is especially true talking about cardiovascular diseases, which take first place in the structure of mortality in the world, including in the Russian Federation. The initial manifestations of atherosclerosis may be formed in early life period. Lipid disorders - dyslipidemia - precedes the appearance of atherosclerosis. 40-55 % of children with dyslipidemia are more likely to have lipid disorders in adulthood too. This review presents data on the prevalence of dyslipidemia, on the causes and therapy features in childhood.

Siberian silkmoth (eggar) Dendrolimus sibiricus Tsch., (1908) is one of the most dangerous forest pests in the Republic of Tyva. Outbreaks of this phytophage in the republic occur frequently and cause significant damage to forests. Studies in Tyva were initiated by A. I. Cherepanov, N. G. Kolomiets, N. F. Reimers and others in the 50-70s of the XX century. They described the phenology of the Siberian silkmoth, the biological and ecological aspects of its life activity. In this paper we tried to summarize all the accumulated knowledge of the Siberian silkmoth in Tyva. The chronology of the Siberian silkmoth outbreaks was restored using the collected and analyzed data. We demonstrate that outbreaks of the Siberian silkmoth in the Republic of Tyva are most frequently observed in the forests of Shagonarsky, Chadansky and Turan forestry districts. On the whole, five outbreaks were registered: in 1954-1966, 1969-1975, 1979-1985, 1997-2000, and in 2009-2011. Duration of the outbreaks was 13-7-7-4-3 years and the intervals without outbreaks were 2-1-2-1 years. The fragmented character of the obtained data on outbreaks shows the need for their verification by dendrochronological methods. Valid analysis of data is possible with the use of control tree species not susceptible to the Siberian moth damage and some parameters of the annual rings, for example, optical density of the wood.

The characteristic of forest resources of one of the most forest-provided subjects of Russia - Primorsky Krai is given. Currently, despite the presence of a large area covered by forest - 77 % of the total area of the region, the diversity of wood and non-timber resources is low-quality forests. Practically all operational plantations and part of protective forests are harvested by industrial methods of logging. Now they are represented by degraded low-grade tree stands. This is due to the fact that, the most important industries in the region are those of harvesting and processing of wood, which accounts for more than 80 % of all forestry income. Along with forest management, effective development of forest complex is associated with the use of non-timber resources, food and medicinal plants (although this market is predominantly shadow), as well as the use of the territory of the forest fund for geological study of the subsoil and mining. At the same time, the depletion of forest resources, caused by their extensive use, can lead to a significant decrease in timber harvesting and depletion of the ecological and protective potential of the territory in the near future. It is necessary to pay attention now to rational forest management and the creation of specialized farms to provide, along with the wood, nutritional and medicinal forest products.

The structure and seed bearing of stands, factors of episoil medium, quantity, vitality and age structure of Scots pine undergrowth 15 years after the disastrous crown and surface fire, which occurred in 2004 in insular pine forest in northern forest-steppe of Western Siberia (Kurgan region), were studied. The studies took place at six sample plots (0.3-0.5 ha) located in two predominant (88 %) types of pine forests - cowberry-short grasses-moss and bilberry-bracken - at four types of burns: 1) «burn under the forest canopy», 2) «thin stand burn», 3) «open burn with peripheral insemination» and 4) «open burn without insemination». The reliable differences in pine regeneration in different types of burns in both types of forests were specified. They were conditioned mainly by differences in their stand density and dissemination levels. The total pine regeneration level in forest-steppe was several times less than in pre-forest-steppe. This was connected with extreme dryness of the studied climate period and low seeding of stands, damaged by the intensive fires. The renewal role of dissemination of 2003 which took place simultaneously with the fire; absence of mouse-like rodents (main seed consumers), as well as sharp change of sex ratio in pine populations (to female dominance) due to intensive surface fire have been shown. On the whole, the total summer precipitation played the main role in pine regeneration of all burn types in forest-steppe zone of Western Siberia.

Current ages of felling in the forests of Belarus were established in 2001. In production forests they make up 81 years and more for coniferous stands, 101 years or more for hardwood, 61 years or more for birch trees, 51 years and more for black alder -, aspen - 41 years and more. The current age of logging does not correspond to high-grade assortments for coniferous and alder stands. In Belarus, due to the improvement of the structure of forests over the past 25-30 years, adequate conditions have been created for improving the methods for determining cutting ages and a certain increase in ages and turnovers. Changing the harvesting ages requires the formation of a new regulatory framework in connection with the adoption of a new Forest Code. Recently, new cutting ages for the forests of the Republic of Belarus have been developed and adopted. They are formed on the basis of quantitative and technical ripeness of the forest, taking into account ecological requirements. New logging ages for conifers (pine and spruce) of the II grade and below have been increased by 10 years; for ash, the logging ages are reduced; for black alder the ages was raised by 10 years. The adopted changes are not supposed to induce marked increase in the size of the calculated cutting area, and the output of commercial timber at the plantations of pine, spruce (site productivity grade II and below) and black alder will not rise substantially in the near future. The alignment of the age structure of tree stands due to new cutting rules is expected to produce the effect no earlier than 2050-2060.

Any movements of forest machines under the forest canopy are harmful for the stand. Their tracks and wheels damage the soil surface: strip off the litter, disturb the sequence of horizons, alter soil hydro-physical properties. These impacts affect the root content of soils. Especially sensitive in this sense is the spruce, whose roots are mostly concentrated in the topsoil which is disturbed by vehicles. To address the problem of stand damage, it is essential to wisely choose the logging technology and machinery. The widely used practices in Karelia are tree-length skidding by crawler tractors, as well as cut-to-length harvesting. The study aimed to assess the effect of various partial cut practices on soil density and the mass of spruce roots up to 3 mm thick in the middle taiga of Karelia. Soil density was studied in skid trails and in the interior of forest blocks not accessed by machines; root masses were compared. The method of soil monoliths sampled from skid trails and blocks throughout the logging area was used. Cutting to length by machines (harvester + forwarder) was found to cause the heaviest topsoil compaction, as compared to mechanized cut-to-length harvesting (chain-saw + forwarder) or tree-length skidding. Root mass in the trail and inside the block, where machines did not reach, remained different for 12 subsequent years whichever practice was used. The difference was the greatest in the first several years after logging. Soil density in the trail recovered at a faster rate than the root mass.

Climate change has a direct impact on the forest ecosystems of the boreal zone. Temperature increase has a stimulating effect on the advancement of a tree line along the elevation gradient, increase of tree radial increment and stand density. The object of the study was the stands formed by the Siberian pine growing in the forest-tundra ecotone of Kuznetsk Alatau Mountains. The rate of timberline and tree line advancement were estimated using GIS-technology and field research. It has been established, that the beginning of the Siberian pine advancement along the elevation gradient coincides with the period of air temperature increase. Estimated speed of tree line advancement is approximately 0.2-0.3 m/year; timberline ~ 0.5 m/year. The average radial increment after 1980 was 25 % higher than the radial increment over the same period of the previous years. At the same time after a marked increase of the radial increment in the early 1980s, a negative trend is observed up to the local minimum of 1999 ( r ² = 0.52). Dendroclimatic analysis indicates a negative influence of July-September temperatures ( r = -0.63) and that of winter precipitation ( r = -0.81) on radial increment, while the amount of July-September precipitation ( r = 0.54) and root zone wetness content during the vegetation period ( r = 0.73) show positive correlation with radial increment. During the previous period from 1967 to1982, a negative effect of winter precipitation on radial increment was also noted ( r = -0.69), whereas May-June temperatures demonstrated a positive effect on radial increment ( r = 0.66).

Scots pine forests are extremely fire hazardous. They show high fire frequency compared to other forest formations. This is due to their high natural fire danger, as along with high recreation activity, which is determined by a fairly dense road network and frequent forest attendance. Moreover, about 90 % of all forest fires are caused by residents. High fire frequency in the forest-steppe Scots pine stands results in silvicultural and economic waste. In the forest-steppe pine forests, partial logging (selective, gradual, etc.) is carried out quite frequently, which has a certain impact on fire danger, fire resistance and post-pyrogenic characteristics. One of the possible ways to reduce negative effects of forest fires is to improve resistance of Scots pine stands. The development of evidence-based fire prevention measures requires assessment of fire resistance. The paper identifies the main factors of fire resistance of Scots pine stands. These factors include forest fuel loads, average diameter of trees, average bark thickness, average distance to the crown, average depth of the roots, the proportion of deciduous species in the stand and in the undergrowth, density and height of regeneration. The paper provides an adequate assessment of fire resistance of partially (selectively) logged Scots pine forests of the Krasnoyarsk forest-steppe. Evaluation of fire resistance is made according to point system using the weighted sum of points.

Results of reconstructions of ground forest fires on bogs of middle taiga subzone in the Priyenisei Siberia are presented for the Holocene. The stratigraphy analysis of the peat deposit, layer-by-layer peat ¹⁴С dating and morphological study of the pyrogenic interlayers allowed to estimate the time of fires, their periodicity and intensity. It was established that the intensity and periodicity of fires were different in southern (the key plot «Krivlyak») and northern (the key plot «Razvilki - Khoiba») parts of the Sym-Dubchess interfluve. 6 pyrogenic interlayers were revealed in the bog peat deposit on the key plot «Krivlyak», and their age was the following: 8015 years ago (y. a.), 6795, 2675, 2280, 1780, 1550 y. a. The interval between fires according to the data of «Mochazhina» profile was 4515 years, the one of the «Bugor» profile was 5340, 895, 230 years. All the fires were low intensive and didn’t greatly influence bog formation process. The 16 pyrogenic interlayers were recorded in stratigraphy of the bog on the key plot «Razvilki - Khoiba». It was stated that the low intensive fires took place 7790, 7412, 5958, 5745, 5030, 2339, 1351, 1099 y. a. The high intensive fires which had a considerable impact on the change of bog phytocoenoses and on the rate of peat accumulation occurred 12237, 7174, 5940, 5427, 4914, 2187, 2072, 1957 y. a. The interval between fires in each profile of this plot varies greatly. Frequent repeatability of forest fires was noted in the Atlantic and in the first half of the Subatlantic periods. In the late Holocene the change in forest and forest-bog phytocoenoses of heavily flooded swamp hummock ridge - bog hollow complexes with dominating Sphagnum fuscum (Schimp.) H. Klinggr.in moss cover took place. The impact of forest fires on the peripheral part of bogs in key plots stopped during this period. The fires on the studied bogs contributed to the revitalization of forest forming process. Post-fire successions were mainly manifested by birch and birch-pine grass phytocoenoses.

The results of the study of isozymes variability of Scots pine populations growing in the southern taiga and forest-steppe of Central Siberia are presented. For the analysis 16 polymorphic loci were used. Two age groups (adult trees and undergrowth) are compared for the main indicators of genetic variation. The greatest deficiency of heterozygotes and a statistically significant level of inbreeding was found in the progeny of a small isolated population most disturbed by cuttings from the vicinity of the city of Achinsk. This population was distinguished by the high genetic distance of Nei (1972) between compared generations of trees, comparable to the distances between geographically remote populations. In the majority of other population samples exposed to lower anthropogenic pressure, the average level of heterozygosity was noted, or the observed heterozygosity was higher than expected in two age groups of trees, and deviations from the equilibrium state were found for individual loci, which, as a rule, do not coincide in adult trees and sprouts. The results of the study show that the genetic structure of the populations of Scotch pine Pinus sylvestris L. is quite resistant to the average level of anthropogenic (recreational) load. But the greater negative effect of using forest is associated with an increased risk of loss of allelic diversity (in 3 populations from 8 to 10.0-14.5 %) and, accordingly, the adaptive genetic polymorphism of populations. The necessity of using more sensitive than allozyme markers of genetic polymorphism of species populations (DNA markers of the nuclear and, especially, of the cytoplasmic genomes) in order to detect more subtle disturbances and initial stages of negative processes for the resumption of the gene pool of the processes was noted.

The application of biotechnological approaches for producingnumerous tree species, including pedunculate oak Quercus robur L. , may become the only way to preserve and reproduce unique breeding objects, which is of great importance for practical forestry. It is now possible to clone individual trees with valuable properties and scientifically advantageous genotypes. In experiments on clonal micro propagation of oak, juvenile plant material (seedlings) was grown in the laboratory. The use of additional stage of rearing and micropropagation of explants of one-month seedlings on media with different volume of 6-benzylaminopurine (6-BAP) showed the expediency of this procedure. When applying ex vitro media, many cultures continued to develop axillary or adventive shoots, the height of which was 11-15 mm (depending on the concentration of 6-BAP). The results of this study will help to cope with the difficulties associated with the induction and preservation of the morphogenic potential of explants in the process of repeated subculturing. The highest rhizogenic response (73 %) was achieved for the micro buds of juvenile material on BTM medium with full composition of macronutrients and indolylbutyric acid (IBA) at a concentration of 0.3 mg/l. It was also found that the combination of IBA and 1-naphthalenacetic acid (NAA) in concentrations of 0.2 and 0.1 mg/l, respectively, completely suppresses the development of roots in micro shoots of pedunculate oak. Of the 4 tested substrates, the highest increase in oak seedlings was observed in the variant with forest oak soil and sand (5.0 cm). The use of two-stage adaptation of regenerative plants ensured their 100 % survival in the laboratory and greenhouse. The use of soil as a substrate, taken from natural oak plantations, will significantly reduce the cost of the process of growing planting material.