Home – Home – Jornals – Avtometriya 2026 number 4

We analyze the composition of : rocks and provide age estimates for detrital zircon grains extracted from sandstones of the tuff-turbidite sequence in the Dzhida Zone of the Central Asian Fold Belt. The sandstones are classified as feldspathic graywackes based on their mineralogical and petrochemical characteristics and are interpreted as first-cycle sediments. The detrital material consists predominantly of volcanic rock fragments, with plagioclase grains being subordinate. Relatively low values of the chemical index of alteration (CIA = 58-68) indicate moderate to weak chemical weathering of lithic components. This reflects the low maturity of the detrital material, which was derived primarily through mechanical breakdown of source rocks. The U-Pb age distribution for detrital zircons from the tuff-turbidite sandstones is bimodal, with major peaks at 530 and 510 Ma. No Neoproterozoic zircon grains were identified in the samples studied. The graywacke composition, low sediment maturity, and the observed U-Pb age distribution of detrital zircons collectively suggest that these deposits accumulated in a forearc basin setting, with detritus supplied from local sources - namely, Early Cambrian volcanic rocks of the Dzhida ensimatic island arc.

LA-ICP-MS dating of zircons from a tuff bed in the Bolshoi Patom Formation in the Ura Uplift yielded an age of 633 ± 7 Ma. The Vendian reference section in the southern Siberian Platform therefore includes the last Cryogenian (Marinoan) glaciation, whereas the postglacial Vendian succession is entirely Ediacaran. Using the obtained age estimate of the Bolshoi Patom Formation, we considered chronostratigraphy of the Riphean-Vendian deposits in the Ura Uplift and in the adjacent areas. The available geochronological and sequence-stratigraphic indicate the presence of a hidden stratigraphic unconformity above the glacial horizon at the base of the Vendian sequence, caused by glacioisostasy.

Located in the north-west of the Murmansk Region, the sulphide Cu-Ni ore deposits were discovered in the 1930s. Nowadays they provide approximately 8-10% of the nickel mining in Russia. The deposits are spatially associated with serpentinite massifs, which have long been assigned to either the ophiolitic complex or basalt magma differentiates. The magma is regionally represented by wide-spread fields of pillow lavas and gabbro-diabase sills. The ultramafic ferropicritic volcanic rocks, which alternate in cross-section with lavas and basaltic tuffs, were discovered in the 1970s. Initially the ore-bearing massifs were intrusions composed of peridotite (wehrlite), clinopyroxenite, and gabbro, which were tectonically metamorphosed during the Svecofennian orogeny. Based on petrological, geochemical, and isotopic research, scientists have proved that ferropicritic volcanic rocks and ore-bearing intrusions are genetically bonded. This paper concerns the processes of differentiation of all the ferropicritic magma facies, i.e., intrusive (ore and ore-free intrusions), volcanogenic (massive and pillow lavas, stratified flows, sills), and dike ones (dike bodies, cross-cutting intrusions, and dike swarms in the Archean surrounding host rocks). Their relations, time and sequence of formation have been revealed. We also discuss the role that the processes of contamination and assimilation of the Archean basement rocks and hosting sulphide carbonaceous schists have played in sulphide ore formation.

We present data on the finds of glendonites (pseudomorphs after cold-water ikaite) in Permian, Jurassic, and Lower Cretaceous sedimentary rocks according to the drilling results of borehole KS-1, located on the coast of the Laptev Sea. This is the only section in the world that contains both Paleozoic and Mesozoic glendonites corresponding to three geological systems. We have found glendonites at all previously known stratigraphic levels in northern Siberia, excluding intervals with relatively rare glendonite finds (Oxfordian, Ryazanian, and Valanginian stages). There are the most numerous, diverse, and large glendonites in the Middle Jurassic interval of the section (Bajocian-Callovian). The KS-1 borehole is a unique natural archive that reflects significant late Paleozoic-Mesozoic events of cooling in the region under study.

We present the first reconstruction of a lacustrine sedimentary environment for the extensive area of the Angara steppe (Baikal peripheral basin) in the late Holocene with decadal temporal resolution. The reconstruction is based on the results of a comprehensive study of lacustrine sediments from Lake Ordynskoe: petromagnetic and granulometric parameters and biogenic silica content. We have determined sedimentation rates and the age of the reconstructed events using radioisotope dating (²¹⁰Pb and ¹³⁷Cs). The age of the core base is 2800 cal yr BP. The results show that the primary contribution to the magnetization of sediments from Lake Ordynskoe, unlike other studied lakes in the region, comes from grains produced by magnetotactic bacteria. However, the behavior analysis of biogenic components of magnetization provides information on the lake bioproductivity and relative changes in redox conditions during the formation of sediments at the water-sediment interface, and the results of granulometry are informative for reconstructing relative changes in the lake level. Despite this particularity in the formation of the lake’s petromagnetic sediments, we have established that noticeable anthropogenic impact on the geosystem of Lake Ordynskoe began approximately 280 years ago, significantly increasing in the last century due to agricultural activity.

This paper describes a system for monitoring the seismicity of specific volcanic regions in Kamchatka (Russia, Kamchatka Peninsula) with an assessment of the seismicity level according to the SESL’09 (Statistical Estimation of Seismicity Level) methodology. The application of the SESL’09 methodology for the purpose of investigating the preparation of volcanic activations is a promising direction in conducting volcano status monitoring. We present the results of identifying seismically active source volumes for 10 active volcanoes in Kamchatka, for which nomograms have been constructed that allow for the estimation of the seismicity level for any given time interval based on the seismic energy released within it. Examples of variations in the seismicity level of these volcanic regions associated with the preparation of an eruption are provided, confirming this conclusion.

The article presents algorithms for numerical modeling of electrical micrologging signals and calculation results in geoelectric models of impermeable rocks and the borehole environment of a porous, permeable reservoir. This research may be useful for developing an integrated approach to the quantitative interpretation of electrical logging data. A joint numerical analysis of electrical logs measured by conventional probes and microprobes will enable refining the radial electrical resistivity distribution in the borehole environment of oil-gas reservoirs. This, in turn, will provide additional information when jointly solving the problem of drilling mud filtration and numerical inversion of electrical logging data, resulting in a more accurate assessment of reservoir porosity and permeability. We have developed software for numerical simulation of electrical micrologging signals - those from a microgradient and micropotential probe and a microlaterolog probe with focusing. We employ a finite element (FEM) algorithm with an arbitrary position of the probes in a cylindrically-layered geoelectric model, and a finite difference (FDM) algorithm for the microgradient and micropotential probe in a horizontally-layered model. Test calculations of the signals in geoelectric models of Western Siberian terrigenous deposits are presented. The models describe impermeable sediments as well as layers with the mud cake and invaded zone at different resistivity ratios. The model parameters correspond to Lower Cretaceous oil-gas reservoirs exposed with polymer-clay drilling muds. An analysis of the calculated micrologging signals reflects a small investigation depth of the microgradient and micropotential probe, and a strong dependence of the signals on the drilling mud and mud cake resistivities. Numerical modeling in the class of a cylindrically-layered model has allowed us to obtain the radial resistivity change in the borehole environment of an oil-gas reservoir.

A detailed study of an alkali beryl sample (vorobyevite) from the Shuk-Bul rare-metal lithium pegmatite (Sangilen Highlands, Tuva) was conducted using electron microprobe and ion probe(SIMS) analysis, X-ray diffraction, EPR spectroscopy, infrared absorption spectroscopy, Raman spectroscopy. The empirical formula of beryl studied was calculated: (Na_0.2Cs_0.1)_∑0.3(Be_2.7Li_0.3)_∑3.0Al₂Si₆O₁₈·0.7H₂O. The ratio of water types I and II in beryl channels is estimated. Beryl from the Shuk-Bul deposit shows significant similarity in trace element composition with beryl from another lithium pegmatite deposit of the Sangilen Highlands (Kara-Adyr). Together, they differ from beryl from LCT-pegmatites of Afghanistan and the Kola Peninsula (the Shongui deposit) in their increased content of alkali metals - Cs and Rb, as well as F, and reduced – Fe and Mg. The content of Na and Li in beryl from Tuva deposits is comparable to the Shongui deposit and exceeds the values for beryl from LCT-pegmatites of Afghanistan. The presence of paramagnetic centers H⁰ in beryl, formed from water molecules under the influence of radioactive irradiation, has been established. Using a Calvet microcalorimeter, the enthalpy of formation of the studied beryl was determined (−9245 ±11 kJ/mol) by dissolving it in a 2PbO∙B₂O₃ melt at T=973 K, the standard entropy was estimated (390.7J/(mol∙K)), and the Gibbs energy of formation was calculated (−8696 ±11 kJ/mol).

This paper presents new isotope-geochronological, rock magnetic and paleomagnetic data for the Berezinovsky and Tayandinsky Early Carboniferous volcanic complexes of the East Ural zone of the Southern Urals. The cover nature of the basalts is demonstrated, lava flow patterns and their directions are identified, and the strikes of the subvolcanic bodies are clarified. Using the LA-Q-ICP-MS laser ablation method, an age of 339.0 ± 1.0 Ma was obtained for rhyolites of the Berezinovsky complex. It is shown that by this time, the East Ural zone had already accreted to the East European Platform and formed a single structure with it.

An analysis of oil and gas potential prerequisites forms the basis of a zonal forecast strategy for oil and gas-promising areas and ensures rational subsoil use. The relevance of the study stems from the need to replenish the hydrocarbon resource base by discovering new large gas accumulation zones. The oil and gas potential of the Upper Paleozoic-Mesozoic deposits of the Vilyui hemisyneclise was predominantly influenced by the post-Jurassic stage of tectonic development, which is associated with the formation of the main structures—oil and gas accumulation zones—and faults capable of acting as channels for hydrocarbon migration from the Permian source strata to Upper Permian, Lower Triassic, and Lower Jurassic reservoirs. The distribution patterns of hydrocarbon deposits in the largely sandy section of the Mesozoic sedimentary cover of the Vilyui hemisyneclise are largely determined by the stratigraphic and areal distribution of seal rocks, which controls the main gas reserves.

This paper examines the geological setting of the two strongest earthquakes recorded in the Altai-Sayan mountainous region in 2025: the Beltirskoe earthquake (ML=6.4) and the Kuraiskoe earthquake (ML=5.7), which occurred on opposite margins of the Chagan-Uzun block. Data on the aftershock sequences of these earthquakes are presented. The analysis demonstrates that these earthquakes occurred in the vicinity of, yet outside, the source region of the 2003 Chuia earthquake. The 2025 events were studied with reference to available data on the aftershock activity of the Chuia earthquake. It is shown that the Chuia earthquake is associated with the shear zone of the eponymous fault and encompasses a linear area along one of the margins of the Chagan-Uzun block. During the main shock, the block itself was incorporated into the source region in the form of weak earthquakes occurring beneath it at depths of 10–20 km (a seismically active layer adjacent to the Chuia earthquake source zone). The focal mechanisms of the Beltirskoe and Kuraiskoe earthquakes are thrust-type, whereas the mechanisms of all strong aftershocks of the Chuia earthquake are strike-slip. Both 2025 earthquakes generated aftershock sequences of low intensity. The hypocenters of the main events and the majority of aftershocks are located at shallow depths, with a maximum concentration at approximately 3–5 km. The 2025 earthquakes represent a continuation of seismic activity in the Altai region within the near-field zone of the Chuia earthquake, reflecting a delayed temporal response of crustal blocks that experienced alterations in their stress state following the impact of a major seismic event.

This paper presents the results of a study conducted on the chemical composition of ores from the Marinskoye orogenic gold ore field, located in the Allakh-Yun metallogenic zone of the Okhotsk-Koryak metallogenic belt (South Verkhoyanye). The deposit developed in a suprasubduction setting over the course of three discrete stages of ore formation: the early-ore stage (the Tithonian of the Late Cretaceous), the late-ore stage (the Aptian of the Early Cretaceous), which was associated with the exhumation of early ore-bearing complexes, and the telescoping of the late mineralization into early and post-ore stages. The main ore-bearing vein mineral is quartz; less common minerals include Fe-dolomite, dolomite and sericite. Ore minerals: primary – pyrite; secondary – arsenopyrite, galena, sphalerite; rare – native gold, pyrrhotite, boulangerite, hessite, petzite, sylvanite, tsnigriite, chalcopyrite, electrum, tetrahedrite, freieslebenite, diaphorite, stephanite. Ores from the early ore-forming stage are composed of quartz–sericite–carbonate–pyrite, arsenopyrite–pyrite–quartz, gold–galena–carbonate and telluride–sulphotelluride–sulfosalt associations; the total sulphide content in the ores is 1-2%. The metasomatites contain sparse inclusions of cubic crystals of arsenic-bearing gold-bearing pyrite (C_{As mean} = 1.17±0.06 wt%, С_{Au mean} = 3.4±0.3 g/t). The early vein association consists of quartz with significant impurities of Ni (up to 61 g/t) and Cd (up to 4.3 g/t) and a low content of REE (SREE = 0.5-1.2 g/t). The fineness of native gold ranges from 660 to 780‰. Hessite, silvanite and tsnigriitehave been described for the first time at the Marinskoye deposit. In ores from the late-ore stage of mineralization, quartz–pyrite, pyrite–quartz, gold–polysulfide–carbonate, and Ag–sulfosalt associations have been identified, with sulfide content increasing to 5%. Low-arsenic pyrite with a pentagonal-dodecahedral shape is characteristic of the wallrock and quartz-carbonate veins. REE concentrations in quartz reach 29.6 g/t, their distribution shows enrichment in light lanthanides (LREE/HREE = 13.4-13.8), and a low-amplitude positive Eu-anomaly (Eu/Eu* = 1.3-1.6). In grains and aggregates of low-grade gold (up to 600‰), electrum rims and veinlets are prominent. The post-ore stage of mineral formation consists of minerals belonging to the quartz-carbonate association. The established general and distinctive properties of the mineralogical and geochemical composition of the ores of a different age at the Marinskoye deposit are essential for evaluating metallogenic potential of the telescoped ores.

Monitoring tasks often require the installation of temporary or local densification of existing seismic networks. The high cost of standard broadband seismometers limits the possibilities of increasing the number of stations. An alternative is to replace them completely or partially with more low-cost seismic exploration geophones with the expansion of the recording frequency range by low-frequency deconvolution. A methodology is proposed for assessing the applicability of geophone-recorder equipment sets for seismological monitoring tasks based on measurements of the recorder's hardware noise and the passport characteristics of the geophone sensor. It is shown that only the use of modern low-noise recorders and low-frequency geophones provides sufficient sensitivity for monitoring local and regional seismicity. A new method has also been proposed for determining the maximum allowable value for frequency correction of recording a specific earthquake (for this, the amplitude-frequency response of recording the recorder's hardware noise and recording after deconvolution are iteratively compared). It turns out that the more intense the earthquake, the more effective is the expansion of its recording spectrum. Using the example of recording the Kolyvan earthquake (M =4.3, epicentral distance of 30 km), the possibility of restoring the recording spectrum to 0.3 Hz for a geophone with a natural frequency of 4.5 Hz is shown. Due to this, the signal amplitude increased by more than 3 times, and the process of identifying phases and determining the arrival times of target waves was significantly simplified. It is shown how, using the seismic mode at the location of the proposed network installation, it is possible to assess whether the earthquake records produced by the proposed kit will be distorted and to determine its applicability in advance. The method has been tested using the example of equipment selection and data processing of a temporary seismological network in the Lena River delta.

Cross-view geolocalization is the process of establishing correspondence between images of ground objects obtained by surveillance equipment deployed on different platforms, provided that the images generated by the equipment on one platform are geodetically referenced. A cross-view geolocalization method is proposed based on the detection of landmarks e field of view of an unmanned aerial vehicle (UAV) video camera using the YOLOv12 neural network, trained on georeferenced satellite images containing these landmarks. The training set is formed by augmenting the images of the specified landmarks. The results of experiments obtained using a sample from the SUES-200 dataset containing 20 satellite images of various landmarks and 20×50 images of these landmarks obtained by a UAV onboard camera from an altitude of 300 m are presented.

This paper examines the design of algorithms that minimize the localization time of an unknown signal source that manifests itself by generating ultrashort (essentially instantaneous) pulses at random moments. The source being searched for is random in two respects: first, its position within the search interval is unknown, and second, the source generates pulses at random moments. The source is localized using a detector receiver capable of arbitrarily changing its viewing window at any moment in time. Optimal search algorithms are constructed for the case where the a priori probability density function of the source distribution is a two-level piecewise constant function. The optimal parameters of these algorithms are determined, including the expected execution time for each of them. It is proven that an optimal algorithm that takes into account a priori information about the intensity of the source being searched for is always more efficient than an algorithm for which this intensity is unknown.

Suppose one needs to check whether given square matrices A and B are congruent. If A and B are nonsingular, one can use such useful instruments as the cosquares of both matrices. How can one reduce the case of singular A and B to a nonsingular one? Sergeichuk and Horn in 2006 proposed a method that brings a given singular matrix A by a finite sequence of congruences to a direct sum of a nonsingular submatrix and one or several nilpotent Jordan blocks. The blocks constitute the singular part of the canonical form of A with respect to congruences. Removing them from A yields the desired method that replaces the input singular matrix by a nonsingular submatrix of smaller order. The method of Horn-Sergeichuk was not implemented by its authors as a working procedure. In this paper, we describe our implementation of this method in the form of an algorithm for rational matrices or complex matrices whose entries are rational Gaussian numbers. The algorithm is based on the error-free arithmetic of rational numbers, which is provided to the users of the computational environment Matlab. The performance of the algorithm is illustrated by two numerical examples.

In this paper, we study a numerical method to approximate a solution with weak singularity at the initial time of non-linear fractional integro-differential equations. For this we use fractional order Legendre polynomials as a basis and reduce the given problem to a finite dimensional problem using a spectral collocation method. We theoretically prove the exponential convergence rate of a function approximation based on the fractional order Legendre polynomials and, on this basis, present an error analysis of the proposed method. We provide some numerical examples to show the convergence rate and efficiency of the proposed method.

In this article, we introduce a class of nonlinear fractional Lane-Emden equations incorporating Jumarie's fractional derivative with Neumann boundary conditions. To compute approximate numerical solutions, we propose an efficient modification of a variational iteration method (VIM) termed the fractional variational iteration method (FrVIM). Notably, for the limiting case our problem reduces to the classical Lane-Emden equation. We illustrate the effectiveness of our approach through graphical representations of solutions obtained using both Jumarie and Caputo derivatives. Furthermore, we observe that when the order of derivative approaches 1, the fractional solution plots gradually converge to the classical solution, demonstrating the accuracy and reliability of our method.

In this paper, a new fast compressive Fourier collocation algorithm for high-dimensional diffusion equations is constructed. A new algorithm is based on the high-dimensional sparse and fast Fourier transform and the compressive sampling matching pursuit algorithm. The computational complexity of the proposed algorithm is proportional to d², where d is the dimension of PDE domain. The error of the approximate solution is estimated and some numerical experiments are given.

The hyperbolicity preserving numerical solving of equations is a fundamental problem of computational mathematics. In the presence of relativistic effects and a magnetic field, the problem becomes even more complicated. The construction of numerical methods for solving continuum mechanics problems that allow one to control the hyperbolicity of a system of equations in solving the equations is an important problem formulated by Sergey Konstantinovich Godunov. This paper proposes an approach to constructing a Godunov-type scheme using a method of formulating the equations in the form of symmetric hyperbolic systems. An important property of this formalism, in addition to hyperbolicity control, is the use of all waves in solving the Riemann problem, which allows one to reproduce the tangential discontinuities with the quality of the Roe and HLLC schemes. The use of an operator splitting into the pressure forces and the advective transfer in the Riemann problem makes it possible to eliminate the ``sonic point'' problem, which may occur in Roe-type schemes. The scheme is verified by using some classical tests on the breakdown of a discontinuity in one-dimensional and two-dimensional formulations.

Based on the idea of Ogita and Aishima [1] and Ulm's method [2], we designed an inexact Ulm-type method based on matrix multiplication for inverse singular value problems, which avoids the shortcomings of solving a system of linear equations in each iteration of the algorithm in [3]. Thus, it looks more stable and requires less computations. Under the condition that the given singular values are distinct, the algorithm has the quadratic convergence in the sense of root convergence. Moreover, numerical experiments in the last section show that the new method is better than some known algorithms.

This paper presents the results of a dissipation and dispersion analysis of a linearized version of a novel finite difference scheme for the fully nonlinear weakly dispersive shallow water equations. It is a modification of the Rusanov scheme, which is a third-order approximation of the gas dynamics equations. We derive stability conditions, phase change and phase error formulas, and investigate the behavior of the harmonic attenuation coefficient. The study uncovers some previously unknown properties of the Rusanov scheme. Notably, both the original and the modified schemes exhibit high order smallness in the phase error for long waves. Furthermore, we identify the optimal parameter values that ensure monotonicity of the harmonic attenuation coefficient, strong suppression of short-wave harmonics, and small change in their phase.

With the swift advancement of artificial intelligence technology, automatically solving plane geometry problems has emerged as a popular area of research. To improve the automatic solution effect of mathematical plane geometry problems, an efficient deterministic prediction model is constructed by combining the powerful feature extraction ability of transformer, the time series processing ability of long short-term memory network, and the generation ability based on the bidirectional encoder representation of transformer. The outcomes of the ablation experiment show that the model proposed by the research performs the best in regard to accuracy and score, with 92.5% and 0.91%, respectively. The inference time is 0.45 seconds, significantly better than other models. In addition, the accuracy of this model in text relationship extraction, geometric element detection, and graphic annоtation is 97.88%, 93.68%, and 95.36%, which is significantly better than other comparative models. The application effect analysis results show that the proposed model maintains a low average number of steps and the highest accuracy of 96.21% as the number of theorems increases. The model proposed by the research exhibits higher robustness and stability when dealing with problems with different step numbers, providing a new approach for automatically solving plane geometry problems.

Stable carbon isotopes are widely used in environmental sciences to study physiological, ecological, and biogeochemical processes associated with ecosystem, regional, and global carbon cycles, providing information on various temporal and spatial scales. The study was conducted in forest ecosystems of the middle and northern taiga subzones of Central Siberia. The δ¹³C composition of the tree, shrub, dwarf shrub, and moss-lichen vegetation layers, fungal fruiting bodies, litter, and soil cover of the studied forests was analyzed. A pronounced δ¹³C gradient was observed across vegetation layers in forest ecosystems. δ¹³C values n the biomass of aboveground components of ecosystems ranged from -34.0 ± 1.0 ‰ in the green moss glittering woodmoss ( Hylocomium splendens (Hedw.) Schimp.) of the middle taiga to -23.8 ± 0.8 ‰ in the wood of Gmelin larch ( Larix gmelinii (Rupr.) Kuzen.) growing in the northern taiga. Both the lowest and highest δ¹³C values were found in the lowest, moss-lichen layer. The tree layer of the studied middle taiga ecosystems is characterized by lower δ¹³C values in the leaf apparatus compared to the northern taiga stands, reflecting their higher productivity and the degree of discrimination (Δ) of the heavy carbon isotope during photosynthesis. The heavier isotopic composition of the subordinate vegetation layers in the northern taiga forests indicates a reduced canopy effect. Isotope fractionation during soil organic matter mineralization leads to an increase in δ¹³C values with depth in all studied ecosystems. However, based on the dependence of δ¹³C values on soil carbon content, which varies with depth, an increased carbon turnover rate (β) was detected in larch soils in the permafrost zone. This is presumably due to post-pyrogenic dynamics of root detritus input, rather than the intensity of mineralization processes.

The article presents the 37-year dynamics of survival of different populations of Scots pine ( Pinus sylvestris L.) (climatypes) tested in provenance trial growing in the southern taiga of the Krasnoyarsk Krai on disturbed sod-podzolic sandy soil. A significant ( p < 0.001) negative correlation of this indicator with the duration of the frost-free period at the point of origin is shown. For a group of climatypes with a frost-free period of > 125 days, a significant ( p < 0.05) negative correlation with precipitation in May-June was shown, which confirms the creation of a water shortage at the test site for this group of climatypes. In the comparative analysis, the climates were divided into sectors according to the continentality of the climate type. The best survival within each sector is often noted in pine trees from taiga zones. During the analysis, climatypes from broad-leaved forests and forest-steppe zones were noted, which have relatively high survival values and are not similar in terms of forest conditions to the test site.

The drained peat soils were studied (Drainic Hemic Histosols). The drained area of the mesotrophic swamp is occupied by young pine forests ( Pinus sylvestris L.) - sedge-sphagnum, reed, and mixed-grass-nettle at interchannel lanes of 94, 47, and 25 m, respectively. The average annual level of swamp waters - 23.2 ± 9.9, 42 ± 11 and 70.2 ± 16.0 cm characterizes the conditions of weak, moderate and intensive drainage. During May-October of three years, environmental indicators characterizing the aerophysical properties and volume humidity of soils were studied. In the ranked series of volume humidity, the 81-100 % class dominated in conditions of weak drainage, 20-60 % - moderate, and < 20-40 % - intensive drainage. In soils with moderate and intensive drainage, good aeration conditions prevailed (air capacity 21-90 %), the oxygen content in the aeration pores corresponded to atmospheric, and the class of redox potential, characterizing intensive oxidative processes, prevailed. In weakly drained soils, variants of good air capacity and to varying degrees of unsatisfactory (< 10-20 %) were equally common. The oxygen content of the soil air in 18 % of the relative frequencies dropped to 11-16 %. Against the background of mainly oxidative processes, weak reducing (300-400 mV) were observed in 9 % of the frequencies. In order to quick predict the air properties of peat soils when planning measures of drainage in peat lands, paired adequate models of the relationship between aerophysical parameters and volumetric humidity by the type of linear function and a quadratic parabola were constructed. According to the linear regression coefficients, an increase in humidity by 1 % is accompanied by a decrease in air capacity by 0.91 %. The points of extremum (maximum) of the parabolic function of volume humidity - 35.9 % and oxygen of soil air - 20.6 %, corresponding to atmospheric content, are calculated. The critical points of a maximum humidity of 42.9 % and a redox potential of 619 mV characterize the intensive development of oxidative processes. Based on the constructed model, a range of volume humidity of 65-80 % is predicted, which ensures a moderate course of oxidative reactions (redox potential 500-600 mV), preventing accelerated (unproductive) «combustion» of peat deposits. The range of application of regression equations is 8 (13) - 97 (93) % of the volume humidity.

The article presents data on the dynamics of natural restoration of the Siberian stone pine ( Pinus sibirica Du Tour) under the canopy of light coniferous and deciduous forests and in logging areas carried out by selective logging in the Central ecological zone of the Baikal natural territory, Baikal mountain forest region. Periodic fires including catastrophic ones in 2015-2017 constrain considerably Siberian stone pine forests development here postponing their formation for many years due to absence of a stable Siberian stone pine undergrowth. In a series of areas, especially on the slopes of northern expositions of the Morskoy Ridge, self-seeding of Siberian stone pine did not occur due to the fires, which destroy generative tree stands. Long-term secondary forest of other formations and typology form on the site of burnt here Siberian stone pine taiga. It is stated that around the ridge, under the canopy of mixed light-coniferous and deciduous forests, a rather sustainable Siberian stone pine undergrowth with a stable annual growth forms. Presence of Siberian stone pine undergrowth in these forests on self-seeding base indicates positive dynamics for Siberian stone pine forests formation under these conditions for forests growth. Evidently, it is reasonable to create conditions for forests keeping with available potential for Siberian stone pine taiga formation in the areas of the studies.

The article discusses the method of constructing growth tables of the uneven-aged larch ( Larix Mill.) stands grouped into economic groups of forest types. The method is based on typical growth lines of forest survey indicators obtained by converting absolute values into indices of 106 tables of the growth rate of larch. Affine transformations of age series significantly reduced the absolute variability of inventory indicators, and reduced it to zero at the age of 100. The probability types of growth in height, diameter, and species number were found through regression relationships between these indicators and the classes of bonitet and thinning types. The last two indicators were taken as independent variables. The thinning pattern of larch stands with age fits into 12 typical lines. The difference in indices between thinning types 1 and 12 at the age of 20 reaches 72 %, and at the of 220, it reaches 86 %. The relationship between thinning types and class of bonitet, types of growth of height, diameter is moderate, reliable. There is no relationship between thinning types and classes of density. Different density in 100 years can have a thicket of one thinning type and vice versa. Absolute values of the number of stems, average heights and diameters in 100 years are determined by regression equations of the relationship of these indicators with classes of bonitet. In other ages, their values were found by multiplying the indices of the standard lines by the absolute values of the indicators in the base age. The species number was determined using the species height. As a result, growth tables were constructed for uneven-aged larch stands grouped into economic groups of forest types. The productivity of the developed tables differs slightly from the productivity of normal larch stands. The proposed method of constructing growth tables can be used in modeling the growth of stands with a limited number of test plots.

The photosynthetic activity of Scots pine ( Pinus sylvestris L.) needles growing in swampy forests in the subzones of the northern and middle taiga of the European Northeast has been studied. Some ecological aspects of photosynthetic fixation of carbon dioxide by needles in sphagnum and sedge-sphagnum pine forests are considered. The features of the daytime and seasonal dynamics of photosynthesis and its relationship to environmental factors are revealed. It has been established, that in summer, during the daytime, the intensity of photosynthesis largely depends on the intensity of solar radiation. There is a positive relationship between pine photosynthesis and temperature and humidity during the day. The daily productivity of photosynthesis of pine needles growing in the middle taiga sphagnum pine during the growing season has been determined. The fixation of carbon dioxide by needles is greatest in summer under favorable light, thermal and edaphic conditions, about 50 % of carbon was absorbed during photosynthesis in July. The linear dependence of the daily productivity of photosynthesis on the air temperature and the total photosynthetically active solar radiation per day is shown. It has been established that the daily photosynthetic productivity of pine needles within the taiga zone of the Komi Republic decreases with increasing geographical latitude. The optimal values of the main environmental factors have been determined, at which the maximum level of photosynthetic activity of needles is manifested during the summer growing season. The variability of the light and temperature optima of pine photosynthesis in the zonal aspect has been revealed.

This paper presents comparative estimates of the input volumes and fractional composition of plant litter in a 15-year-old cereal birch forest and a 25-year-old tallgrass alder-willow birch forest, representing the initial stage of tree and shrub vegetation overgrowth on an abandoned arable land in the Cherepovets district of Vologda Oblast. The total litter input averages 1942 kg ha/year and does not differ between the biogeocenoses. 85.2 % of the litter is classified as the active fraction. The predominant fractions for the biogeocenoses are birch ( Betula L.) leaves and twigs, as well as alder ( Alnus Mill.) and willow ( Salix L.) leaves. The cereal birch forest, in contrast to the tallgrass alder-willow birch forest, is characterized by higher inputs of aspen ( Populus tremula L.) seeds and leaves and lower inputs of willow fractions (branches and leaves). Maximum litter fall input occurs in August-September (27-35 % of the annual input). The peak in the cereal birch forest occurs at the end of August, and in September in the alder-willow tall-herb birch forest. The minimum litter fall input for both types of biogeocenoses occurs during the dormant period (November-March) - 15 % of the annual input per month. The average input of carbon with litter fall is 861.5 kg C/ha/year, and nitrogen - 22.8 kg N ha/year.

The article analyzes the achievements and studies of the famous Siberian scientist, Candidate of Agricultural Sciences (PhD) Vadim Ivanovich Polyakov in the field of forest survey, forest management, forest use, forestry and protective afforestation in the northern, central and southern parts of Central Siberia for the period from 1980 to 2018. V. I. Polyakov made a significant contribution to the study of the dynamics of black fir-Siberian stone pine forests in the middle mountains of the Western Sayan. Based on the study of the dynamics and structure of mortality, the stability of tree stands with age, the average and maximum lifespan of Siberian stone pine ( Pinus sibirrica Du Tour) and Siberian fir ( Abies sibirica Ledeb.) were assessed. He also proposed a Markov model of the growth of stands, constructed taking into account the influence of factors of self-thinning of tree stands. Using factual material V. I. Polyakov revealed the cyclical nature of forest formation in Siberian stone pine forests of different ages, and determined the ages of quantitative, technical and natural maturity of Siberian stone pine and Siberian fir generations. He devoted considerable attention to research into the patterns of growth, development, vital status and productivity of forest stands in the impact zone of the enterprises of the Norilsk Nickel Polar Division, as well as production and experimental forest crops from coniferous tree species growing in the southern taiga and forest-steppe regions of Krasnoyarsk Krai. He provided invaluable assistance in the development of regulatory materials for the survey of protective forest stands of various functional purposes, as well as in the study of their current state, growth rate, structure and biological productivity in the steppe and dry steppe zones of Krasnoyarsk Kray, Republics of Tyva and Khakassia. V. I. Polyakov developed algorithms and programs for compiling taxonomic characteristics of stands based on the measurement data of registered trees and corresponding computer thematic databases of stationary observations, which significantly facilitate tracking of monitoring objects. A list of the main scientific publications of V. I. Polyakov is presented, which gives an idea of the subject matter of his studies, its geography and significance.

This article is dedicated to the 95^th anniversary of the outstanding scientist, Academician of the USSR Academy of Sciences and the Russian Academy of Sciences Alexander Sergeevich Isaev. It presents historiographic materials and the author’s personal recollections of the life and work of A. S. Isaev.

Currently, more than 55 % of the world’s population lives in cities, and this figure is projected to increase by 70 % to 2050. One of the reasons for the mass migration of rural residents to cities is their desire to improve the quality of life. However, the dense construction of high-rise buildings has led to a monstrous concentration of people, which, combined with the growth of urban transport, has reduced the quality of the living environment to a level that poses a threat to human health and life. Today, urban plantings are considered as a universal tool for solving urban problems in terms of achieving an optimal balance between the services provided and the existing risks. Urban vegetation, especially woody one, has numerous properties that improve the quality of the environment and preserve human health in urban environments. The review shows that artificial intelligence methods open up great prospects for solving complex problems of monitoring air quality in the urban environment, and uncertainty about the oxygen-producing role of urban areas is revealed. A technique for automatic mapping of urban trees is presented, and a spatio-temporal neural network training system for assessing the carbon deposition potential of urban forests is described. The possibilities of using machine learning in the assessment and monetization of ecosystem services in urban trees are shown. Based on the results of deep learning, an assessment of the comfort level of the urban environment was carried out in connection with the density of buildings, the degree of greening, and taking into account the results of a survey of residents.

The article discusses approaches to updating the forest fire zoning of the Arctic region of Siberia based on geoinformation analysis and machine learning methods. The analysis of vegetation categories, spectral indices (NDVI), meteorological data series (air temperature, insolation, precipitation, thunderstorm activity) and relief categories is presented in relation to information on remotely recorded thermal anomalies («thermally active pixels») obtained from satellite monitoring data on vegetation fires for 2001-2023. Using the logistic regression method (nonlinear S-shaped coupling function), the weighting coefficients of predictors determining the probability of fire events were determined, among which the air temperature (β = 1.27) and the vegetation index NDVI (β = -0.53) were characterized by the greatest significance. Summarizing the influence of all the considered predictors, four zones are identified in the study area, characterizing the probability of fire events. Verification of the model based on independent data on thermally active pixels for 2024-2025 and the ROC analysis confirmed a high predictive ability (AUC = 84.3 %). It was found that 78.4 % of all thermal anomalies in the period 2001-2025 occurred in zones classified as highly and very likely to cause fires, occupying 24.4 % of the region’s area. A comparative analysis with the existing schemes of forest zoning states the need to shift the boundaries of the Siberian subarctic region (1A) to the north and expand the West Siberian zone (2A, 2B), which is determined by the current dynamics of fire regimes and, probably, economic development of the territories. The results can be used to optimize the system of monitoring and planning fire protection measures in the Arctic under the conditions of predicted climatic changes.

The analysis included indicators for the start and end of fire-hazard seasons, fire areas at detection and suppression, dates and times of detection, containment, and suppression, causes of fires, geographic coordinates, and fire frequency peaks in six groups of regions for the periods from 2015 to 2019 and 2021 to 2025. It was found that the start of the fire-hazard season has shifted by 10-20 days over the past 10 years in the central regions and the Urals. In the south, the dates of the fire-hazard season has shifted to such an extent that the fire-hazard season can be considered a year-round phenomenon ( p < 0.30). Based on the nature of the distribution and intensity of fire frequency peaks in the season four main types can be distinguished: unimodal - one clearly defined peak in July-August, typical of northern regions, such as the Arkhangelsk and Murmansk regions and the Sokha Republic (Yakutia); bimodal - two peaks of approximately equal strength, one in spring and one in autumn-winter, typical of southern regions, particularly the Krasnoyarsk Territory and steppe regions; double-peaked - two peaks of unequal strength, one in spring and one in August-September, typical of the central and Ural regions (Moscow, Sverdlovsk, and Tver regions); multimodal - several peaks of varying magnitude, unevenly distributed throughout the season, typical of the coastal regions of the Far East (Primorsky and Khabarovsk Krais). These patterns must be taken into account when planning forest fire protection.

The article presents the results of a study on the introduction of maple ash ( Acer negundo L.) into phytocenoses in the specially protected natural area (SPNA) «Rudnichny Sosnovy Bor», located within the city limits of Kemerovo. It was revealed that under the influence of the invasive species, the structure and composition of different layers of forest communities were most altered in pine horsetail-forb associations with maple, pine-maple nettle-gramineous associations, pine-maple nettle-goutweed associations with a share of its participation of 12-18 specimens/400 m², and the least altered in the pine goutweed-forb association (2 specimens/400 m²). Under the canopy of maple ash, the projective cover of the herbage was reduced in some cases, dead areas formed. In the herbaceous layer, the proportion of weed species varied from 20 to 50 %, with the dominant species being: stinging nettle ( Urtica dioica L.), creeping couch grass ( Elytrigia repens (L.) Desv. ex Nevski), greater celandine ( Chelidonium majus L.), cocksfoot ( Dactylis glomerata L.), and dandelion ( Taraxacum officinale F. H. Wigg.). Therefore, the introduction of maple ash into the pine forest ecosystems leads to unwanted floristic pollution in a specially protected natural area. Further monitoring of the maple ash invasion process involving is necessary.

The terpene hydrocarbon component composition of the essential oil isolated from the six populations of Siberian spruce needles ( Picea obovata Ledeb.) growing on the eastern macroslope of the Kuznetsk Alatau (Republic of Khakassia) and orographically isolated from each other, was studied by chromatograph mass spectrometry. The essential oil content ranged from 0.042 % to 0.763 %. Thirty-three compounds were identified, representing 99.88 % of the terpene composition. The main groups of volatile substances detected in all studied needle samples were monoterpene hydrocarbons (15.09 % to 33.08 %) and their oxygen-containing derivatives (66.59 % to 84.91 %). The following monoterpenes were predominant: camphene (9.55-15.44), limonene (4.49-6.05), α-pinene (2.35-5.92), β-myrcene (1.20-1.67), santhene (1.45-2.8) % of the total oil content. The following oxygen-containing derivatives were present: bornyl acetate (49.82-83.02), camphor (1.76-5.43), camphene hydrate (1.40-4.42), borneol (1.29-4.05), eucalyptol (1.07-3.30). A high content of bornyl acetate was detected compared to the essential oil of Siberian spruce growing in other regions of Russia. The ratio of the essential oil component groups indirectly suggests that some spruce stands are exposed to stress factors. The obtained data contribute to the elucidation of patterns in the biodiversity of Siberian spruce.

The results of long-term studies of microsporogenesis in autochthonous coniferous species in the northern taiga are presented. The phenorhythmics of microsporocyte meiosis has been studied. Characteristic disorders in meiosis are described. The total number of chromosomal abnormalities in microsporocyte meiosis increases with increasing environmental factors. Teratology of pollen and is described. The total number of anomalies in the total pollen pool is estimated. The number of abnormal pollen grains in the total pollen pool is small. The long-term dynamics of pollen viability has been studied. The indicators of pollen viability in all studied species vary greatly by year. The correlation between the total number of disorders in microsporocyte meiosis, the number of abnormal pollen grains, and pollen viability is not always clear enough. The number of such violations increases markedly only in years with extremely unfavorable weather conditions during microsporogenesis.

Pedunculate oak ( Quercus robur L.) is susceptible to infection by one of the most widespread phytopathogens - ascomycete fungi of the order Erysiphales , the causal agents of oak powdery mildew, which leads to reduced productivity of forest stands of this species. However, the molecular genetic mechanisms underlying resistance of pedunculate oak to powdery mildew remain insufficiently studied. Therefore, the aim of this study was to identify transcription factor and protein kinase genes involved in the development of adaptive responses of pedunculate oak to the powdery mildew pathogen through the analysis of RNA sequencing data. The identification and differential expression analysis of transcription factors and protein kinases were performed using iTAK v2.0.2 and edgeR, respectively. As a result of RNA-seq data analysis, 2,813 significantly differentially expressed genes were identified, including 166 transcription factor genes and 186 protein kinase genes. Under powdery mildew infection, the largest number of differentially expressed transcription factor genes belonged to the MYB (38), AP2/ERF (23), NAC (17), and WRKY (15) families. It was found that, under infection conditions, genes of the WRKY , GARP-G2-like , BES1 , and BBR-BPC families exhibited the highest expression levels compared with the control. In contrast, genes belonging to the C2C2 , bZIP , HB-HD-Zip , C2H2 , SBP , B3 , zf-HD , SRS , OFP , and HB-WOX transcription factor families were downregulated under powdery mildew infection. Analysis of differentially expressed protein kinase genes in infected pedunculate oak trees revealed that the majority belonged to the RLK/Pelle family (167 genes), displaying both up- and downregulation patterns. Other protein kinase families - AGC , NEK, Group-Pl-2 , ULK , and WNK - were predominantly downregulated, CAMK genes were upregulated, whereas STE and TKL families showed bidirectional regulation in response to infection. The identified genes may be considered promising candidates for further functional studies aimed at elucidating their contribution to powdery mildew resistance in pedunculate oak.

Peat bogs occupy about 3-4 % of the Earth’s land area, they play a significant role in climate formation, river flow regulation, gas exchange with the atmosphere, and also make a significant contribution to the global carbon cycle. Therefore, the study of carbon accumulation in the biomass of various tiers of swamp forest systems is a priority aspect. Although much attention has been paid to assessing the biological productivity of swamp forest systems, there are significant problems with obtaining objective information about the organic carbon cycle in swamps. In particular, there is no data on the biomass of the main and lower tiers for the swamp forest systems of the Urals. In this study, for the first time for the Middle Urals, four sample plots were established in the gradient of distances 450, 200, 110 and 70 m from the Lake Iset (56.95°N, 60.39°E), on which the survey indicators of stands and the structure of the aboveground biomass of all functional plant groups were determined. The heights of the sample plots above sea level were 250-253 m, and the groundwater level varied from 0 to 5 cm from the surface. The average age in this gradient decreased from 163 to 37 years, the average tree height from 5.5 to 2.2 m, and the stem volume from 127 to 13 m³/ha. It was found that in this gradient, the biomass of the woody tier decreases from 77 to 8 t/ha, and the biomass of the lower tier increases from 1 to 4 t/ha. The comparison of the obtained results with data from other regions showed that the proposed indicators of the biomass structure of the woody and lower tiers have regional specifics.