Home – Home – Jornals – Russian Geology and Geophysics 2023 number 3

Until recently, the sedimentary cover age and composition of the marginal North Kara Basin (northern part of the Kara Sea, Russian Arctic) remained uncertain because of the absence of direct data from parametric and exploration wells. Taking into consideration the absolute importance of these issues for understanding the regional geology of the Arctic shelf and evaluating its petroleum potential, Rosneft Oil Company, together with AO RosGeo, drilled ten shallow stratigraphic wells in fall 2020 using the research vessel (RV) Bavenit to reveal the complete stratigraphic range of the North Kara Basin. The ultrahigh-resolution (UHR) seismic survey was carried out by the RV Kapitan Voronin to adjust the well site locations and integrate the well sections into the regional geological model based on 2D seismic data during the drilling campaign. As a result, 300 m core was recovered from 11 Paleozoic and two Mesozoic stratigraphic units, previously investigated by 2D seismic and outcrop studies of the Severnaya Zemlya Archipelago. Lab analyses (biostratigraphy, lithology, sedimentology, geochemistry, and other types of core analysis) were performed at Lomonosov Moscow State University. We present obtained lab results confirming that the main part of the North Kara Basin section belongs to the Paleozoic; late Cambrian-Late Devonian rock ages have been derived. Several Paleozoic units tend to be older than those in previously published models. Core samples include mainly terrigenous rocks with insignificant carbonate presence. Paleozoic units are overlain by a thin Mesozoic terrigenous section dated from Middle Triassic to Middle Jurassic above a distinct angular unconformity. After a thorough analysis of all the lab results, we will obtain data on the ages of sedimentary units, as well as their lithology and depositional environments, and establish elements of the hydrocarbon system (source rocks, reservoirs, and seals) to evaluate the North Kara Basin petroleum potential with lesser uncertainty. We suppose that our results will significantly contribute to establishing a stratigraphic framework, reconstructing the basin history, and evaluating the petroleum potential of the whole Arctic region.

The author focuses on complex loading of a granular material at continuous rotation of the principal strain axes. The described testing procedure reveals the stress dependence on the relative velocity of rotation. It is possible to use the velocity of rotation of a unit volume relative to the velocity of rotation of the principal strain axes in the constitutive equations for a continuum.

The plane and axially symmetric 2D numerical modeling of rock mass blasting is carried out using the Lagrangian tensor-based method. The results are compared with the actual direct measurements of rock mass permeability in the near zone of underground nuclear explosion Dnepr-1 in Khibiny in 1972. The post-explosion permeability of hard rocks is assessable at an admissible accuracy using the calculated shear strain intensity. A case-study of rock mass permeability change assessment in the near zone of blasting of a complex configuration charge is discussed.

The gravity flow of granular materials in axially symmetric convergent channels (V-shaped bunkers) is analyzed using the discrete element method. The symmetrical radial flow becomes unstable under certain conditions, and a space-time structure forms in the medium. The flow becomes essentially nonradial and asymmetric - the material is discretized into blocks, and the field of velocities inside the material becomes discontinuous. Further deformation reduces to relative movement of the blocks as rigid bodies.

In this study, the swelling behavior of sand-bentonite mixtures and pure bentonite are investigated by considering different factors, such as bentonite content in the mixture, specimen preparation method by applying different compactive efforts, and varying effective stress levels. Compaction tests were performed on the specimens of the sand-bentonite mixtures with 10% and 20% bentonite contents and pure bentonite. The maximum dry unit weight and the optimum water content of the specimens with 20% bentonite were relatively higher than specimens with 10% bentonite. Pure bentonite specimens had a lower maximum dry unit weight and higher optimum water content compared to sand-bentonite mixtures. Specimens of the swelling tests were prepared at the optimum water content values. Up to a vertical effective stress of 25 kPa, the mixtures showed a swelling behavior. Under the effective vertical stresses of 50 and 100 kPa, it was evident that the specimens behaved in the compression side. It was seen that the application of either 10 or 25 blows by means of compactive effort in pure bentonite specimens had a neglectible effect on the swelling behavior.

The article describes the rotary drilling modeling using the two-mass system of a drill string with a crush-and-shear hybrid drill bit. The head resistance of rocks on the bit is determined non-linearly: the penetration rate is added with the strength loss in the supporting medium under impact. The scope of the analysis embraces the continuous force generated by the rotating bit and the pulsed impacts by the drill strings at the end-points of the bit-bottomhole detachment. The initial conditions of the post-impact process, which define the initial penetration rate and the speed of the bit, are determined with regard to potential stick-slip effects. The numerical modeling proves that, as against the torsional vibrations, the axial-torsional vibrations of the drill string often result in the chaotic dynamics of drilling.

In this paper, the effect of elevated thermal treatment on the physico-mechanical parameters of Chunar sandstone from Mirzapur district of U.P. was investigated. The studied area is represented geologically by the Vindhyan Supergroup from Meso to Neproterozoic age. Sandstone of Chunar area, Mirzapur, U.P. has been granted the tag of Geographical Indication (GI) under the category of natural goods in 2019. Mechanical strength tests (indirect tensile and uniaxial compressive strength) were performed by a universal testing machine. Samples were treated at elevated temperature in the electric furnace at different temperatures for conducting mechanical and physical tests in each sample and results were recorded. The results suggest that for sandstone, high temperature treatment leads to volume expansion, weight reduction and a decrease in density as well as the reduction in the strength characteristics. Up to 200°C there is an inappreciable increase in indirect tensile strength and compressive strength but after 200°C strength gradually decreases. Beyond 400°C, the P-wave velocities showed a sharp decline due to elevated temperature treatment induced cracks in the heated sandstone.

The strength, elasticity and deformability testing of cemented paste backfill is carried out. The test backfill compositions include fine and very fine natural sand with the increased content of clay and dust, and refined with sifted granular blast-furnace slag 0-5 mm in size. The uniaxial compression strength, elasticity modulus and Poisson’s ratio are determined in the test backfill compositions at different stages of curing. The ultimate uniaxial compression strength is correlated with the P-wave velocity and elasticity modulus determined in the static and dynamic tests of the backfill compositions.

In this paper, De Moura and Butt model is extended to the large diameter drilling applications. The model proved to be effective and highly accuracy in predicting drilling performance in 19 distinct RBM and TBM operations even in the presence of datasets with high dispersion.

The authors substantiate the design of an excavator’s end effector for joint rock crushing and loading. The structural layout and parameters of hydroimpactors included in the end effectors of mining machines are described. The physical model of the hydroimpactors is constructed, tested and adjusted. The test data on the dynamics and outputs of the model at different power fluid flow rates are compared. The simulation model of the hydroimpactor is constructed and verified using the test data. The capabilities of the hydroimpactors are calculated for the planned modes of operation. For the excavator’s end effectors, it is proposed to use the hydroimpactor design with the lagged return travel of the piston toward the flexible adjustment of the hydroimpactor performance and to reach the required impact capacity at lower flow rates of power fluids.

It is important to enable remote control of duty cycle of air hammers via external distributors meant to set impact frequency. A new general layout is developed for the air-driven impact impulse generator with smooth adjustment of impact frequency at constant energy in driving construction elements in soil. The experimental model of the machine is designed and tested. Based on the analysis of the impulse indicator diagrams of the machine duty cycle, the impact frequency is correlated with the piston choke cross-section for three configurations of the control unit. The impact frequency control limits are found.

The spotlight is on reversal ventilation in a mine in case of an accident in winter. The inlet of cold air in underground openings endanger the health of miners, and mining equipment suffers from an adverse effect of negative temperatures. In compensatory measures design, the source data is the potentially transient distribution of mine air temperature after airflow reversal. The procedure of air temperature pattern in ventilation shaft during airflow reversal involves mathematical modeling of transient thermal processes in the shaft and in adjacent rock mass. The correct choice of the heat transfer coefficient between the shaft lining and air results from the comparison of the modeling results and the experimental data on the air temperature dynamics in planned airflow reversal.

The article describes the tests of thermal treatment effects on magnetic properties of bauxites and the results of their dry magnetic separation. Under increasing temperature in a muffle furnace to 600 °С, the magnetic susceptibility of treated bauxites decreases. The thermal radiation modification of bauxite by accelerated electrons under the same temperature improves the magnetic properties of the mineral. Magnetic separation efficiency is governed by the thermal treatment conditions. The process parameters to ensure extraction of rare and rare earth elements to the magnetic fraction are found.

In this study, modeling and optimization tests were conducted on enrichment of chromite ore by Knelson concentrator. For this purpose, the three-level Box-Behnken experimental design method was applied. The analysis of variance (ANOVA) was used at 95% confidence interval to test the significance of independent variables and their interactions. In order to estimate the chromite concentrate grade and chromite concentrate recovery with independent variables, quadratic polynomial regression equations were derived. Maximum concentrate grade of 54.77% and concentrated recovery values of 77.1% were reached in 12 l/min fluidization water flow rate, 1124.57 rpm bowl speed, and 21.05% solids ratio. The coefficient of multiple determination (R²) was calculated as 0.996 for concentrate grade and 0.991 for concentrate recovery. This indicates that the proposed model is a usable and effective model.

The monomineral extraction of molybdenite and stibnite is tested and analyzed using non-frothing flotation, adsorption, IR spectroscopy, multiple frustrated total internal reflection and potentiometric measurements. The ionized sulfhydryl collectors tested at concentrations of 10^-4 mole/l in a pH range of 2-12 include butyl xanthate, diisobutyl dithiophosphate, diisobutyl dithiophosphinate and sodium diethyldithiocarbamate. The test nonionized collectors are diesel fuel and O-isopropyl-N-ethyl thionocarbamate. Molybdenite shows higher floatability than stibnite in application of individual collectors in a pH range of 4.5-8.0. Stibnite is better floatable with diisobutyl dithiophosphate, while molybdenite flotation is more active with diesel fuel. The general critical concentration found for the modifiers H₂O₂ and Na₂S₂O₃ is 4.4·10^-3 mole/l-the flotation activity of molybdenite and stibnite is minimal at this concentration of the agents. Different sorption forms of the ionized sulfhydryl collectors are proved by the multiple frustrated total internal reflection infrared spectroscopy. Anisotropism of mineral electrodes Sb₂S₃ and MoS₂ made along and across the crystal lattice cleavage is experimentally confirmed. The ratio rating of grains of low-oxidizable sulfides, broken along the cleavage or in other direction relative to the cleavage, can modify the process properties of molybdenite and stibnite.

The influence of coarseness of magnetite is examined in iron concentrates after wet sieving analysis. The test concentrates are the products of Olkon, Karelskiy Okatysh and Stoilensky GOKs. It is shown that magnetic susceptibility of the concentrates gradually reduces with the decreasing size of magnetite particles in the material < 50 µm and assumes the minimal values in the sieve residue < 8 µm.

The article describes the studies into the mineralogy and process properties of ROM gold-copper-porphyry ore from the Svoboda site of the Malmyzh deposit in the Khabarovsk Krai. The tests and analysis reveal the structure and texture, and mineral composition of the ore, as well as the occurrence forms of gold and silver. The ore characteristics which govern the difficulty of the selective flotation are determined. Efficiency of Cu, Au and Ag extraction in the bulk and copper flotation cycles is described, and the causes of loss of the minerals are discussed. The resultant copper concentrate contains gold and silver, while the presence of Bi, Te, Se and admixture of In, Cd in chalcopyrite add to the value of the concentrate. Magnetite extracted from the bulk flotation tailings contain some platinum (0.5-2.0 µm) and admixtures of Ti, V, Mn, Cr and Cu.

The authors appraise application of milky quartz from the Larino lode deposit in production of high-purity quartz concentrate with the total content of impurities less than 50 ppm. The structure and texture of milk quartz are analyzed using the optical microscopy and ICP-OES spectrometry methods. The elemental analysis data of the preconcentration and deep concentration products are compared. The low contents of the impurity elements in the deep concentration products of quartz from most lodes of the Larino deposit prove the applicability of this quartz material as a feedstock for the production of high-purity quartz concentrates.

The authors discuss feasibility of high-tonnage direct inclusion of overburden in composites for the construction of road layers at mines. It is found that overburden has a strength as per State Standard GOST 23558-94 and the prolonged dedusting effect. The optimal contents of the binder and fly ash are 8 and 10% by mass, respectively. Mechanical activation of fly ash for 1 min enlarges its specific surface by 2 times. The frost-resistant composites modified with mechanically activated fly ash and stabilizer (1% by mass) have the strength grades M20-M40.

The scope of overburden investigation embraces overburden volume, physical state, mineralogy and chemistry, content of toxic elements, hydraulic/thermal/physical/mechanical properties, compositional analysis and potential process flows with a view to manufacturing materials of construction. It is found that the mineral and chemical compositions of overburden in coal mining are the same as the mineral raw material has, and the content of toxic elements is within the allowable concentrations. These rocks are classified as modulus-active and highly active, and are thermally inert. The integrated processing of overburden in coal mining enables using these rocks as a feedstock for the production of heat-insulating, ceramic, binding and road construction materials.

Extraction processing of pine needles ( Pinus sylvestris Ledeb.) allows obtaining the products that are used to manufacture the goods in medical, food, perfumery and cosmetics, and other branches of industry. At the same time, the post-extraction residue of needles (PERN), being a specific lignocellulose raw material, has not yet found proper (effective) use for obtaining innovative products. Using the method of thermogravimetry in a nitrogen atmosphere (TG/DTG), a number of thermal decomposition patterns of PERN have been established. Based on the results of TG/DTG, the kinetics of PERN pyrolysis was analyzed, the thermodynamic parameters Δ H , Δ G and Δ S were calculated. The average values of Δ H , Δ G and Δ S are 246.3, 160.3 kJ/mol and 135.7 J/(mol · K), respectively. According to the method of the fourth derivative of DTG contour proposed by us, a detailed “fractionality” of mass loss during heating of PERN under the conditions of thermogravimetric test has been established. The values of the apparent rate constant are calculated, indicating the multistage (I-V) process of thermal decomposition. By means of analytical flash pyrolysis of PERN, 66 pyrolysis products were identified. Among them, 35 compounds were identified that are not found in pine bark and wood pyrolyzates and can be in demand in organic synthesis, in the production of technical and food products, perfumes, medical products, etc . The obtained results are basic for designing the manufacture of technical products with increased added value and scaling of heat treatment technologies and pyrolysis of similar plant raw materials.

In order to develop a technology for the chemical processing of methane from the coal industry into valuable products, conditions for the reactions of combined steam/carbon dioxide and autothermal reforming of methane were optimized. The effects of temperature (600-900 °C), volumetric feed rate (50-400 mL/min), contact time (0.04-0.45 s) and the molar ratio of components (O₂/CH₄ = 0.25-1.0, CO₂/H₂O = 0.5-2.0) of the reaction mixture on the conversion rates of initial reagents (CH₄, CO₂, O₂) and the yield of target reaction products (H₂, CO) were studied. It has been shown that the use of combined reforming allows regulating the H₂/CO molar ratio within a wide range (4.1-0.9). Optimal process conditions have been established to ensure the complete conversion of methane and the maximum yield of useful products for the effective utilization of methane-air mixtures in coal production with the generation of a hydrogen-containing gas.

The composition and transformation dynamics of saturated hydrocarbon biomarkers in the coal of the Sergeevo deposit were studied using gas chromatography and gas chromatography - mass spectrometry. Depending on biomarker parameters in the studied section, the layers of allochthonous, autochthonous and mixed origin were identified, differing from each other in the nature and conditions of plant biomass accumulation. Allochthonous coals, enriched with bitumoids and genetically related to terragenic biomaterial, were formed in an oxidative environment. The transition to autochthonous and mixed coals was accompanied by an increase in the contribution from aquagene biomarkers and repeated changes in the facies conditions of sedimentation. Autochthonous coals are distinguished by an abnormal content of higher alkanes and a non-standard distribution of isoprenoid hydrocarbons.

Vanadium precipitation in the form of ammonium metavanadate and polyvanadate from alunite processing solutions is studied. The degree of precipitation of vanadium-containing sediment is determined, depending on solution pH, the initial concentration of vanadium(V) oxide and ammonium sulphate, temperature, and contact time. The results show that ammonium metavanadate (NH₄VO₃) precipitates from the solution at room temperature at pH 8, and when the ammonium metavanadate solution is heated to 90 °C and then acidified to pH 2 and stirred, ammonium polyvanadate (NH₄)₂V₆O₁₆ precipitates. The obtained products were characterized by X-ray phase analysis, infrared spectroscopy, and scanning electron microscopy.

The influence of various technological additives on the plastic and rheometric properties of a rubber mixture is investigated, physical-mechanical and performance characteristics of rubber based on a combination of SKN 4055 nitrile butadiene caoutchouc and Therban 3406 hydrogenated nitrile butadiene caoutchouc are assessed. The rubber mixture included SKN 4055 and Therban 3406, curing agent Luperox F-40P, antioxidant Diaphene FP, fillers: burnt magnesia, carbon black T 900 and P 514, oligoester acrylates TGM-3, MGF-9, and other ingredients. We used Z-50, Z-60, Struktol WB-222, Kvalistrol A-100, B-70 and B-70-20 as technological additives. The rubber mixture was made on laboratory rolls LB 320 160/160, then vulcanized at 150 °C for 60 min and thermostated at 160 °C for 3 h. Studies of the plastic and rheometric properties of the rubber compound, the physical and mechanical properties of vulcanizates were carried out in accordance with the standards existing for rubber industry. The study of thermo-aggressive resistance of vulcanizates was carried out by determining the change in their physical-mechanical parameters after 1 day exposure to air and standard liquid SZhR-1 at a temperature of 150 °C. It is found that the introduction of technological additives leads to improvement in the distribution of ingredients, as well as in the plastoelastic and rheometric properties of the rubber mixture. Rubber containing Kvalistrol B-70-20 has increased physical and mechanical properties, exhibiting the least changes after exposure to aggressive media.

Results of the studies of municipal sewage sludge (MSS) oxidation during pumping a water-oxygen fluid through its bed under uniform (1.5 K/min) temperature ( T ) rise up to 733 K are presented. The temperature dependences of the yield of volatile and liquid products, as well as data on the content of mineral components in the ash residue and water collected at the reactor outlet are obtained. It follows from the temporal dependences of the reactor wall temperature, the power of the ohmic heaters, and the degree of carbon burn-up that the major part of MSS organic matter is oxidized at T < 602 K. According to the data of IR spectroscopy and ultimate analysis, an increase in the oxidation duration and temperature leads to a decrease in the content of hydroxyl and amide groups and an increase in the proportion of aromatic compounds in liquid products. The volatile products obtained at T > 673 K contain only inorganic substances - CO₂, CO, N₂, and NH₃. It is revealed that the major part of nitrogen in the form of NH₄⁺ ions passes into the aqueous phase, while the elements Si, Ca, Al, Fe, P, S, K, Na, and Mg are concentrated in the ash residue.

The article presents a geochemical interpretation of data on the physicochemical properties and individual composition of oils and condensates from the Bovanenkovo and East-Bovanenkovo fields (the distribution of light hydrocarbons (HC) C₃-C₈, n -alkanes, acyclic isoprenanes, steranes, terpanes, arenes). The main purpose of this study is the identification of the main sources of HC fluids, as well as geological and geochemical processes that have affected their composition and the formation of deposits. It is shown that the formation of naphthides from both fields occurred in several stages with the participation of the organic matter (OM) varying in genotype, in particular due to the widespread processes of secondary migration and reformation of primary deposits. Oils and condensates from the Jurassic deposits of the Bovanenkovo field were established to have a genetic relationship with the terrestrial OM of the Lower and Middle Jurassic strata, which was a source of both liquid and gaseous hydrocarbons and subsequently formed these oil and gas accumulations. It is assumed that the naphthides of the Neocomian part of the section are derivatives of the aquatic OM in the Bazhenov formation. These gas-condensate deposits during their formation were differently enriched with light components generated by the terrestrial OM of the Lower and Middle Jurassic strata. The effect of biodegradation processes on the composition of condensates of the Aptian and Albian-Cenomanian deposits was recorded. Their formation is considered having occurred due to the carbonaceous OM of the Cretaceous strata, which served as a source of primary “immature” condensates with terrestrial composition, which were mixed with secondary-migration HC fluids generated by: the aquatic OM of the Bazhenov formation in the case of gas condensates of the Aptian deposits; terrestrial OM of the Lower and Middle Jurassic strata in the case of the pools of the Albian-Cenomanian reservoir. In addition, the naphthides formed with the participation of aquatic OM are observed to be confined to the East-Bovanenkovo field and the southeastern part of the Bovanenkovo field.

In connection with depleting light oil reserves, oil fields with an increased content of paraffin hydrocarbons and resinous-asphaltene components characterized by high density, viscosity and pour point values are increasingly being put into operation. Their extraction is accompanied by the formation of asphalt-resin-paraffin deposits on the walls of technological equipment and, as a result, leads to additional material expenses associated with increased wear of equipment. The influence of the magnetic field on the structural, rheological and energy characteristics of two kinds of oil, differing from each other in composition, and their emulsions (10 wt. % water) was studied. After magnetic treatment, the component composition of the studied oil-containing systems changes. The effect of the magnetic field on low-paraffin, highly resinous oil is accompanied by an increase in viscosity within the whole temperature range. The viscosity of high-paraffin oil changes only slightly after processing, however, a decrease in the pour point is observed.

The content of 25 chemical elements was determined quantitatively, by means of mass spectrometry and atomic emission with inductively coupled plasma, in natural spring sources, as well as in water from central utility and drinking water supply systems and secondary water purification systems (household filters) for the purpose of exploring the safety of drinkable water for the population of some districts of the Magadan Region. Conformity of chemical element concentrations to the standard quality requirements for drinkable water was determined. The study confirms that water is safe for human consumption with respect to the accumulation of conventionally essential and toxic chemical elements. However, water tests showed poor saturation with physiologically useful elements at all sampling sites in the towns and settlements of the Magadan Region.

The capsule review of the scientific editor for the thematic issue of the Siberian Journal of Forest Science, 2023, is presented, dedicated to forest protection problems in Russia.

The problem of infection and death of valuable Siberian stone pine and fir stands of the Baikal specially protected natural territory as a result of the spread of bacterial dropsy of conifers over thousands of hectares is discussed. The disease was found in Zhigalovskiy, Kachugskiy, Nizhneudinskiy, Slyudyanskiy, Ust-Udinskiy and Shelekhovskiy forestry districts of Irkutsk Oblast, as well as in Gusinoozerskiy, Babushkinskiy, Ulan-Udenskiy and Pribaikal’skiy forestry districts of the Republic of Buryatia. Siberian stone pine and fir trees weakened by bacterial dropsy are damaged by secondary stem pests, such as the six-toothed bark beetle (stenographer) Ips sexdentatus Boern., the striped coniferous lumberjack Trypodendron lineatum Oliv., the black fir barbel Monochamus urussovi Fischer, which in turn weaken the damaged stands, leading them to death, creating migratory foci, and are carriers of the disease. In order to carry out the necessary health-improving forest protection measures, eliminate and prevent the spread of infection, the question is raised about the possibility of using selective forest health felling of dry stands and stands infected with bacterial dropsy in the Baikal specially protected natural territory.

Forest protection, being a practically oriented discipline of forestry, has a rich and interesting history. The first attempts to describe forest pests and measures to control them were made in the work of F .G. Fokel «Collection of Forest Science», published in 1752. «Manual for Officers of the Corps of Foresters «Forest protection»» published in 1843 by V. S. Semenov can be considered the starting point of forest protection. The tenth chapter of the work became the first instruction in Russia on the identification of harmful organisms. In 1843-1845, the Department of Ship Forests issued a «Forest Dictionary» prepared under the guidance of V. E. Wrangel. The dictionary contains a description of 76 pest species and more than 20 species of entomophages, and also describes the causes of diseases for the first time. In 1869, the «Reference book on foresters. Part 1» by A. F. Rudzkiy was published, it includes a significant section on forest protection from pests. The first specialized manual was published in 1872 - «Forest Protection» by N. S. Shafranov. This book discussed in details the causes of the insect pests outbreaks, as well as technologies to reduce their impact. Also, for the first time, attention was paid to reducing the marketable value of wood, issues of its subsequent sale, as well as the mechanisms of trees weakening and dieback. In 1875, the second edition of «Forest Protection» was published, in which a separate part was devoted to fungi that cause diseases and rot of trees. The book of N. S. Shafranov was based on the studies of G. A. de Bari, G. M. Wilkomma, and R. Hartig. In 1880 P. V. Baranetskiy published a handbook for forest owners, foresters and students of the forest protection courses. This book has set a bases for contemporary system of forest pathology.

An analysis was made of the current version of the documents that provide information on the dynamics of the density of pest populations and determine the appointment and implementation of sanitation activities in the forests of the Russian Federation, including the Procedure for the implementation of state forest pathological monitoring, the Rules for sanitation safety in forests; The procedure for conducting forest pathological examinations; Rules for the implementation of measures to prevent the spread of harmful organisms; Rules for the elimination of foci of harmful organisms. It has been established that in the zone of taiga forests, the legal framework for forest protection does not provide representative information on the state of pest populations, sanitation measures do not reduce the number of pests. A proposal has been made to change the scale of condition categories, especially categories 4 (shrinking), 5a (fresh dead tree) and 5d (dead tree). It is proposed to use the population of bark beetles and wood borer insects as the main characteristic of the state of trees along with the state of the crown. When the forest pathological unit is located in a small area inside the forest in wet forest types, it is recommended not to carry out sanitary felling, except in cases of the appearance of dangerous types of pathogens. It is proposed to remove preventive measures and other methods of controlling the spread and reproduction of pests and pathogens that are not related to tree felling from the legal framework of forest protection, and invite responsible forest users to apply these measures based on interaction with the authorized body of the subject of the Russian Federation. It is necessary to exclude from the normative documentation the possibility of burning logging residues, except for cases of development of specific diseases, in which even the transportation of logging residues poses a potential danger to the surrounding plantations.

The problems of protection of Siberian pine forests, that have arisen in connection with the recent invasion of the European pest - the small spruce bark beetle Ips amitinus (Eichh.), which formed the outbreak foci on the territory of the Tomsk and Kemerovo regions, are considered. The complexity of indication and early detection of the species, the assessment of the forest stands state, bark beetle populations indexes in foci, and the implementation of measures aimed at curbing the spread of an aggressive alien species were discussed based on the results of our research. The objective reasons for the ineffectiveness of protecting forests from the alien bark beetle at the present stage are shown: the lack of information and scientific and methodological support for it, taking into account the characteristics of the biology and ecology of the new pest; lack of a developed technology for the practical application of protective measures in the conditions of specific management in Siberian pine forests and legislative conflicts. In connection with the specifics of the invasive situation, a number of innovations in the organization and conduct of forest health monitoring and forest pathological surveys in the Siberian pine forests are proposed for consideration. The necessity of clarifying the scale of damaged trees condition categories by the small spruce bark beetle is substantiated, taking into account the peculiarities of the relationship between the pest and its new host-tree species. The possibilities and prospects of conducting remote observations of the alien bark beetle foci and its distribution with using of unmanned aerial vehicles are shown. A critical assessment is given of measures to curb the spread of pests in forests, permitted by regulatory documents, and their possibilities for solving the problem of Siberian pine forests degradation in the outbreak foci of the small spruce bark beetle. The proposals for effective protection technologies against new invasive pest in Siberian pine forests are formulated.

A laboratory method for studying the fungal phytotoxicity with cut-offs from leaves was tested for the fungus Hymenoscyphus fraxineus the causative agent of ash dieback ( Fraxinus L.) disease. We used 12 cultures of the fungus originating from the native and invasive ranges of the pathogen, and leaves of two species of ash Manchurian ( Fraxinus mandshurica Rupr.) and ash green ( F. pennsylvanica Marsh.) that differed in resistance to this phytopathogen. After cultivation of fungi on liquid nutrient media, the cultural filtrates were applied to cut-offs from ash leaves placed in moist chambers. Necrotization of photosynthetic tissues was noted after the action of exometabolites of some cultures. At the same time, large necrosis have developed only on the cut-offs from the leaves of ash green, which corresponds to the known fact that this species is less resistant to H. fraxineus in comparison with of ash Manchurian. The geographical origin and composition of the culture medium did not affect the ability of cultures to induce necrosis. The analysis of the results indicated a probable positive relationship between the necrotizing activity of the culture liquid and the indicators of the crop biomass yield. It can be assumed that the necrosis inducing factors appeared in cultures at the stationary stage of the fungus growth. No concurrence was found between the results of laboratory tests with leaf cut-offs and field experiments on the inoculation of H. fraxineus mycelium into the trunks of young ash trees. The deficiency of knowledge about the H. fraxineus physiology and the mechanisms of interaction of this phytopathogen with the host are discussed. A conclusion was made about the suitability of the laboratory technique with leaf cut-offs for factors of H. fraxineus phytopathogenicity investigation, which act during the colonization of the photosynthetic part of the crown in sensitive ash species.

Currently, in the dark coniferous forests of the Baikal region, the spread of the disease bacterial wetwood disease is noted, causing the sanitary condition deterioration in the forest stands, and leading to the forest dieback on large territories. Despite the fact that this disease has been known since the beginning of the last century, the question of its’ real pathogen is still open. It is believed that associations of various endophytic microorganisms may take part in the development of pathogenesis. In this regard, it seems relevant to study the composition of the endophytic complex of microorganisms in wood with bacterial wetwood of forest species in order to establish the types of relationships between endophytes and test their ability to initiate a pathological process in conifers. An attempt was made to identify the main endophytic microbiome representatives of the «wet wood» of Siberian stone pine ( Pinus sibirica Du Tour) affected by bacterial wetwood, to assess their phytopathogenic properties and types of relationships between them. The features of the endophytic microbiome of the Siberian stone pine affected by bacterial wetwood in the Slyudyanskoye forestry of the Irkutsk region were studied. With standard microbiological and phytopathological methods we isolated pure cultures of bacteria and studied their characteristics (including virulence). For bacterias identification molecular genetic methods were used. From the infested wood of Siberian stone pine trees affected by bacterial wetwood, a complex of pure microorganisms cultures, not previously described in other studies, was isolated. Among them, opportunistic strains include Rouxiella chamberiensis, Ewingella americana, Stenotrophomonas rhizophila and Bacillus pumilus , which exhibit pronounced virulent properties in relation to indicator plants and ambiguously affect the growth and development of Scotch pine ( Pinus sylvestris L.) seedlings. Mutual impacts of bacteria on each other were noted in the endophytic microbiome of the affected Siberian stone pine wood. Bacillus bacteria showed pronounced antagonistic properties. Basically, in the endophytic community symbiotic relationships were dominated with possible syntrophic connections.

In 2006-2018, 13 species of leaf mining gracillariid moths (Gracillariidae) caused noticeable damage to plants (mainly trees and shrubs) in Siberia, i. e. about six of all moth species known in this part of Russia. Relative damage levels of 50-75 % and > 75 % were recorded for 9 moths, of which 5 species are native pests of poplars ( Populus L.): Phyllonorycter apparella (Herrich-Schäffer), Ph. comparella (Duponchel), Ph. populifoliella (Treitschke), Phyllocnistis labyrinthella (Bjerkander), and Ph. unipunctella (Stephens). Three moth species, namely Acrocercops brongniardella Fabricius, Gracillaria syringella (Fabricius) and Phyllonorycter issikii (Kumata) are alien to Siberia. Their numerous mines were found on leaves of woody plants (oaks ( Quercus L.), lilacs ( Syringa L.), ash ( Fraxinus L.) and lime ( Tilia L.) trees) in Western Siberia (Omsk, Tyumen and Novosibirsk Oblast). Alien origin of Phyllonorycter medicaginella (Gerasimov) and Ph. lantanella (Schrank) in Siberia requires confirmation. Both native and alien moth species showed a tendency to cause significant damage to the plants in artificial (manmade) stands, i. e. in urban green plantings, parks, arboreta, botanical gardens, tree nurseries. Overall 81 % of cases of significant damage by gracillariids was documented in artificial plantings vs. 19 % in forests. The European part of Russia remains the main donor of alien gracillariid species for Siberia. Alien species distribute to Siberia directly or through bridge-effect invasions from the west of Russia.

The outbreaks history of the Siberian moth ( Dendrolimus sibiricus Tschetveraikov, 1908) in larch forests of the forest-steppe at the eastern foothills of the Kuznetsk Alatau mountains (West of the Chulym-Yenisei basin, South of Eastern Siberia, Republic of Khakassia) is reconstructed. Outbreaks of this species have repeatedly covered forests from the Urals to the Far East on an area of more than 1 million hectares. However, there is a lack of long series of observations of changes in the size of the Siberian moth populations. Data on the history of the defoliations caused by it will at least partially fill this gap. For reconstruction, we studied the radial growth in six larch stands, which in the past were subjected to intensive defoliation by the Siberian moth. Using the OUTBREAK algorithm, specific features (abrupt, deep, and prolonged declines in growth) were found in the series of radial growth, indicating defoliation in the past. In total 31 such periods were found in 1740-2017. A study of the frequency characteristics of the chronology of defoliation showed that after the end of the Little Ice Age, the interval between defoliations gradually decreased from 10-11 years at the end of the 19th century to 7 years in the 1930s. Since the 1940s, this interval has decreased to 4-6 years, which we attribute to anthropogenic impact (massive logging and, apparently, more frequent ground fires). The consequence of this was the fragmentation of forest stands and the periodic eliminations of overwintering entomophages by fires. As a result, the frequency of occurrence of the Siberian moth foci in the study area increased either due to its escape from the control of entomophages, or because of the formation of a system of migration foci that existed at different times in fragmented forest stands.

The chestnut gall wasp ( Dryocosmus kuriphilus Yasumatsu; Hymenoptera: Cynipidae) was first found in forests with the sweet chestnut ( Castanea sativa Mill.; Fagaceае) in the area of Sochi, where it became the worst pest of chestnut. By now, the chestnut gall wasp has spread to all territories in which the sweet chestnut grows in the Krasnodar Krai. Besides, the condition of chestnut orchards and forests in this region for a long time cannot be considered satisfactory to chesnat due to the development of cryphonectric necrosis ( Cryphonectria parasitica (Murrill) M. E. Barr) is causative agent of the disease). Control measures against the chestnut gall wasp have not been developed. A treat with pesticides are generally not effective because the chestnut gall wasp take cover inside the galls. And also pesticides can hurt honey bees and other beneficial insects. Moreover, pesticides use unacceptable in specially protected natural territories (SPNT), as well as near rivers, streams and settlements. The use of trunk injections is also impossible because the chemicals can make localize into the honey and nuts. To control the density of this phytophagous insect, the torymid wasp ( Torymus sinensis Kamijo; Hymenoptera: Torymidae), which is its effective specialized parasitoid, was introduced. This entomophage is used as an agent of biological pest control against the gall wasp in countries where entered earlier. The introduction of the torymid wasp allowed to significantly reduce the pest’s population density, at the same time it did not harm natural ecosystems. This is the first case in the history of Russia of targeted introduction of a biological pest control agent into SPNT. The article describes the process of making an official decision, logistics and preliminary results of the introduction of a parasitoid in the territory of the Sochi National Park and the H. G. Shaposhnikov Caucasian State Natural Biosphere Reserve.

An overview and the main content of the reports of the Third All-Russian Conference with international participation «Monitoring and biological methods for controlling pests and pathogens of woody plants: from theory to practice», held on 11-15 April, 2022 in Moscow, are presented.