The fertility of urban soils in the Arctic is limited by harsh climatic conditions and high anthropogenic pressure. In addition to the typical impacts of residential use, recreation, and transportation common in any urbanized areas, the ecosystems of Russian Arctic cities are subject to the technogenic influence of heavy industry hubs, which often serve as the foundation for these cities. Under such conditions, the soil cover of the largest cities in the Russian Arctic — Murmansk, Vorkuta, and Norilsk — has formed. An analysis of the physical and chemical properties of urban soils, an assessment of their fertility, and the limiting factors are necessary for the creation and maintenance of urban green infrastructure, which is one of the key factors in the ecological comfort of city life. This study evaluates the acidity, organic matter and total nitrogen content, availability of mobile forms of phosphorus and potassium in the topsoil of these cities and provides an integrated assessment of their fertility based on the soil-ecological index (SEI) by I.I. Karmanov, adapted within the study for application to northern soils and territories. It is shown that, based on the combination of indicators, the soils of the studied sites form the sequence Murmansk Vorkuta Norilsk, from the most fertile to the least fertile. The influence of anthropogenic factors on soil properties is noted, which can be both positive (a decrease in average soil acidity across all sites) and negative (toxic concentrations of mobile phosphorus in the soils of Murmansk). Based on the obtained SEI values, it is concluded that the soils of the studied sites have relatively high overall fertility, comparable to that of soils in the middle and southern taiga.

Changes in the content and composition of lysimetric water in podzolic soil (Albic Retisol) under mixed middle-taiga stand were studied in the Komi Republic before and after clearcutting. Gravity lysimeters were installed on the key plot at depths of 5 cm (O horizon) and 20 cm (EL horizons). Chemical analysis of lysimetric water and calculation of the removal of elements from the organic and eluvial soil horizons were carried out. It was found that pH, specific electrical conductivity, concentration of elements in the water, and their removal from the horizons after clear cutting did not change much in comparison with the initial values. Changes in the removal of water-soluble carbon (Cws) and nitrogen (Nws) compounds and phenols were revealed. A reliable sharp decrease in the concentration of of followed by its gradual increase after clearcutting (R2 = 0.94), and a decrease in the removal of Cws (R2 = 0.63) from the organic horizon were noted. The opposite pattern was observed for the upper mineral horizon, where a significant increase in both the Cws concentration (R2 = 0.94) and the its removal (R2 = 0.63) took place. An increased removal of Nws with lysimetric water was observed throughout the study period. Peak values were reached on the the second year after clearcutting. The impact of clearcutting on the composition of lysimetric water was largely determined by the removal of the forest stand, changes in the composition of ground-cover plants, and the decomposition of logging residues on the soil surface.

Rheological studies of soil samples with the use of oscillatory amplitude sweep test (AST) method on a HAAKE MARS 40 (Thermo Scientific, Germany) modular rheometer are analyzed. Podzolic soil with a microprofile of podzol (Dystric Albic Retisol) developed on mantle loams in the middle taiga zone of the Komi Republic, near the city of Syktyvkar was investigated.The relevance of this work is determined by the need to standardize the methodology for rheological soil studies to obtain reliable data comparable with the results of other research teams. The rheological properties were assayed at the maximum capillary saturation with the use of ground and sieved soil samples compacted to the bulk densities close to native field values and their noncompacted analogues. The use of compacted soil samples reflects the microstructural state of soils in their natural undisturbed state. The upper eluvial horizons (EL[e–hf]–ELf) are the least susceptible to changes in the micromechanical characteristics during the standard soil preparation for analysis. On the contrary, the compacted samples of illuvial (BT) and transitional (BC) horizons exceed the noncompacted analogues in soil strength parameters (G', τL, and τmax) by an order of magnitude and in the parameters of elastic and plastic deformations (LVE–range and Crossover) by two–four times. The horizons with high content of Al–Fe-humus compounds (ELf and BEL) are the exception; standard preparation of samples from these horizons for rheological analysis causes an irreversible loss in the strength of bonds between soil particles. The main factors influencing the rheological behavior of the samples from different genetic horizons of podzolic soil are their particle-size distribution, the content of exchangeable bases, and the content of organic and organomineral Al–Fe-humus compounds. These factors in combination with the bulk density influence the moisture content of the soil samples and, hence, the contact area and the number of contacts between soil particles. This can either decrease or increase the soil microstructure stability in the samples from the same horizon depending on the sample preparation for the experiment.

Soil studies have been conducted in the middle taiga subzone of Karelia, at a former sand and gravel quarry, where two variants of a remediation experiment—planting of pine (Pinus sylvestris) seedlings into open ground and into peat-fertilized ground—started 30 years ago. Soil formation on the plots without peat application is at the initial stage; the soils are assigned to Relocatic Arenosols (Ochric), and their litter horizons are at the first stage of development. On the peat-fertilized plots, the soils are better developed and are assigned to Skeletic Umbrisols (Arenic) with a distinct litter horizon on the surface. The mineralogical and bulk chemical compositions of Arenosols have been slightly transformed during the past years. In some places, the migration of aluminum compounds is noted in the soil profiles, which may indicate the beginning of podzolization. The mineralogical composition of Umbrisols has changed only in the upper mineral horizon. The distribution of chemical elements along the soil profile in these soils is more contrasting as compared to the Arenosols and is characterized by a distinct accumulation of most elements, especially biophilic elements, in the upper horizons. Acidification of soil material under the impact of vegetation is only observed in the upper 10- to 20-cm-thick soil layer. The different remediation methods have resulted in significant variations in the carbon and nitrogen content. Their accumulation in the variant without peat application is very slow, whereas soil enrichment with peat favors the accumulation of these nutrients. The reclaimed soils contain more labile phosphorus as compared to the background soils.

The assessment of the carbon pool in representative forest stands of the northern, middle, and southern taiga subzones of Central Siberia, located in the territory of the Krasnoyarsk Kraihas, has been conducted. The area of these taiga regions accounts for 87.5% of the total territory of Central Siberia, and they make the main contribution to carbon deposition in this area. The total mass of deposited carbon in the representative stands of the northern taiga is 73970 thousand tons, in the stands of the middle taiga this value is 1257101 thousand tons, and for the southern taiga, it is 2766554 thousand tons. The average mass of deposited carbon for the northern taiga subzone is 13.2 tons per hectare, for the middle taiga it is 44.6 tons per hectare, and for the southern taiga, it is 64.5 tons per hectare. Such differences are due to the zonal characteristics of the natural and climatic conditions in these areas and, consequently, the varying productivity of the forest stands formed in these taiga subzones. The fractional composition of the carbon pool depends on many indicators, primarily on the bonitet (site quality), density, and fullness of the forest stand. For all the considered representative forest stands, the main contribution to carbon deposition comes from the trunks and roots of trees. In the northern taiga, the share of trunks accounts for 49.9% to 66.7% of the deposited carbon, while roots account for 18.1% to 34.8%. For the middle taiga, these values range from 53.8% to 70.4% for trunks and from 13.2% to 33.4% for roots. For the southern taiga, the share of deposited carbon in trunks is from 53.4% to 69.6%, and in roots, it is from 17.7% to 31.9%. The obtained data on the carbon pool of forest stands in the taiga zone of Central Siberia are important for understanding carbon exchange processes in forest ecosystems, as well as for developing effective strategies for the conservation and management of forest areas in the context of climate change.

The article summarizes long-term (2013–2023) monitoring results regarding the species composition and seasonal variations of fleas (Siphonaptera) on small mammals of southern Karelia. The species composition of small mammals is typical of the mid-boreal subzone and is represented by nine species, the most abundant among them being the bank vole (Myodes glareolus (Schreber, 1780)) and the common shrew (Sorex araneus Linnaeus, 1758). The flea fauna is made up of 13 species of three families: Hystrichopsyllidae (6 species), Ceratophyllidae (5), Leptopsyllidae (2). The most common species were Doratopsylla dasycnema dasycnema (Rothschild, 1897) – 44 %, Palaeopsylla soricis starki Wagner, 1930 – 18 %, Ctenophthalmus (Euctenophthalmus) uncinatus uncinatus (Wagner, 1898) – 16 %, and Peromyscopsylla silvatica (Meinert, 1896) – 9 %. The prevalence and the index of abundance of fleas on M. glareolus and S. araneus were 32 %, 0.8 and 46 %, 1.4, respectively. The dominant species of fleas on muroid rodents change in the course of the season; the prevalence and abundance index values are high in January, May, and October. Insectivores showed high infection rates in June and October, while flea numbers in the winter season declined notably. The fleas that parasitize small mammals fall into three major ecological groups: continuous breeders (A. penicilliger), warmseason species (Ct. uncinatus, P. sylvatica, M. rectangulatus, H. talpae, D. dasycnema, and P. soricis), or cold season species (R. integella, P. bidentata). In mid-boreal Karelia, there prevail the parasites whose breeding and imago life occur during the spring-to-fall period. The high abundance of fleas with this type of the annual cycle can be regarded as an adaptation to living in the North.

Organic matter of the soils of cutting areas in the middle taiga of the European part of Russia: data from a model experiment

The Köppen-Geiger climate classification is widely used for mapping the spatial variability of climatic patterns. The paper is devoted to the assessment of future changes in the location of the Köppen-Geiger climate zones on the territory of Yakutia under four scenarios of socio-economic development of IPCC (ssp1–2.6, ssp2–4.5, ssp3–7.0 and ssp5–8.5). The data from the ensemble of global climate models of the CMIP6 project, which includes models that best reproduce the climatic conditions of the region (CESM2-WACCM, CMCC-ESM2, CNRM-CM6-1-HR, INM-CM5-0, MPI-ESM1-2-HR) were used. Averaged monthly mean air temperature and total precipitation data for the periods 2021–2050, 2051–2080, and 2071–2100 were used. Data have been obtained as the sum of the historical climatic norm 1981–2010 determined from the GHCN-CAMS reanalysis (air temperature) and CRU TS v.4.05 (precipitation), and the increments of the corresponding climatic variables between the historical and forecast periods estimated from the model ensemble data. Köppen-Geiger climate zone maps were constructed for the indicated time slices at a spatial resolution of 0.5°. According to the obtained estimates, the most widespread subarctic climate zone (Dfc) will increase its share on the territory of Yakutia at the expense of the zones of extremely cold climates (Dfd and Dwd), as well as the polar tundra climate (ET), and the polar tundra may be displaced from the continental part by the end of the century. Analysis of climate shifts by settlements indicates a transition from extremely cold climate in almost all district centers of Yakutia regardless of the scenarios. Under the unfavorable scenarios spp3–7.0 and ssp5–8.5, the middle taiga landscapes and all district centers of the central group of districts will find themselves in subarctic climate with hot summers by the second half of the century. Under these conditions, forest fire hazard, soil aridity, and cryolithozone degradation will increase. This study contributes to the understanding of future climate change in the region, the resulting mapping materials contribute to public awareness and inform the development of the regional climate change adaptation plan and other strategic planning documents.

Introduction. Siberian bog ecosystems are among the world's largest carbon stores and play a critical role in global climate regulation through the long-term accumulation of organic matter in peat strata. The rate of carbon exchange in these ecosystems is largely controlled by climatic and hydrological conditions. However, the quantitative impact of specific hydrometeorological factors, including temperature, on the rate of carbon fluxes remains poorly understood. The temperature regime of organic bog soils is characterized by high inertia and smaller diurnal and seasonal variations compared to mineral soils, due to the high heat capacity of water and the low thermal conductivity of peat. This stability creates unique conditions for biota, but simultaneously increases the ecosystem's sensitivity to changes in the hydrological regime. In the context of modern climate change, studying the thermal characteristics of bogs is particularly relevant for assessing their functional state, stability, and predicting carbon balance dynamics. The aim of this study is a comprehensive analysis of long-term air temperature patterns in a wetland ecosystem using the Mukhrino research station in central Western Siberia as an example. The study focused on typical raised bogs of the middle taiga subzone located within the Mukhrino research station (60°54' N, 68°42' E). The station is a unique model site with a distinct microtopography of a ridge-hollow complex. The study is based on a 12-year continuous microclimatic dataset (2012–2024) obtained using an automatic weather station. Measurements were conducted simultaneously on two key microtopographic elements: the ridge (a more drained, elevated structure) and the hollow (a depression with excessive moisture). To ensure reliability, the data underwent quality control procedures, including the identification and interpolation of minor gaps, as well as comparative calibration in 2024. Long-term (60-year) data from the Roshydromet weather station in Khanty-Mansiysk, as well as ERA5 Land global climate reanalysis data, were used to provide regional context and verify the data. The analysis revealed pronounced spatiotemporal variability in temperature regimes, closely linked to microtopography and seasonal dynamics. In winter (December–February), under clear anticyclonic conditions and weak insolation, more intense radiative cooling is observed in the hollow. Nighttime air temperatures in the hollow can be 2–4°C lower than on the ridge, where the regime is milder and more stable. In summer (June–August), the situation changes: the better-drained and less humid surface of the ridge warms more intensely. The average daily temperature on the ridge in July can exceed that of the natural wetland by 1–1.5°C. The daily temperature range on the ridge in summer is significantly higher (9–12°C) than in the wetland (3–5°C). In spring and fall, these differences even out. A comparison of data from the Mukhrino station and the Khanty-Mansiysk weather station clearly revealed the urban "heat island" effect. In winter, temperatures in the city are consistently 2–3°C higher than in the natural wetland. Daily temperature ranges in the urban environment are also smoothed out (up to 6°C) compared to those in the wetland (10–12°C). In summer, the differences are minimal, and on clear days, the ridge can even be 0.5–1°C warmer than the city. Global reanalysis data demonstrate general synchronicity of climate trends with field measurements (the correlation coefficient between temperature series on the ridge and ERA5 was r = 0.78). However, systematic discrepancies were identified. ERA5 Land significantly smooths extreme values and daily amplitudes, which is due to its spatial resolution (~9 km²), which averages the heterogeneous landscape, and algorithmic filtering. In particular, nighttime temperature minimums on the ridge in winter (up to -35…-38 °C) are underestimated by 3–5 °C in the reanalysis, while daytime maximums in summer (up to +24…+26 °C) are underestimated by 4–6 °C. This indicates the inability of global models to adequately reflect the intense microclimatic processes within wetland landscapes. This study confirms that the temperature regime of Western Siberian raised bogs is characterized by a complex spatiotemporal organization determined by microtopography (ridge/hollow), underlying surface moisture, and regional climate trends. The significant discrepancies identified between local field measurements, urban weather station data, and global reanalyses highlight the critical importance of long-term local monitoring for a fundamental understanding of wetland ecosystem functioning. Only data with high spatial and temporal detail allows for the accurate assessment of extreme parameters necessary for verifying climate models, accurately calculating carbon balances, and developing scientifically based strategies for the conservation and adaptive management of these vulnerable and ecologically significant natural sites in the face of anthropogenic climate change.

The technology for producing planting stock with a closed root system of the main forest-forming species using a multi-rotation cultivation mode is being improved. In forest nurseries of the middle taiga forest subzone of Russia with a short growing season, the introduction of such a regime is difficult due to the risk of seedlings being unprepared for transplantation to a planting area and low stress resistance. At the end of the growing season in November 2023, a comparative analysis of 1-year-old containerized seedlings of Pinus sylvestris L. was carried out under non-rotation (0rot) and 2-rotation (2rot) cultivation modes in northern latitudes. The experimental 1rotT variant has differed from the 1rot (1-rotation mode) by the use of a shade cloth. Morphometric parameters and the provision of basic mineral nutrients (N, P, and K) have been determined in seedlings. The dynamics of the index of damage to pine needle cell membranes by low temperatures in the autumn period during the transition of the plant from vegetation to dormancy has been studied. The morphometric parameters of the 2rot seedlings, with the exception of the stem diameter, have been lower than those of the seedlings of other variants and have not corresponded to the standard ones. The needles and stems of 2rot seedlings have differed from all variants in increased levels of nitrogen and potassium, as well as phosphorus in the stems compared to the 0rot and 1rotT variants. Unlike other variants, their needles have been bright green and they had not had an apical bud. The needles of seedlings of all cultivation modes in the 1st ten days of September have been resistant to low temperatures only down to –4 °C. The frost resistance of seedling nee dles has increased and in the 3rd ten-day period of October in all variants except 2rot the needles have not been damaged even at –25 °C. The 2rot seedlings have differed from other variants in their reduced frost resistance of needles from the 2nd ten-day period of September. Considering the possibility of frosts in the autumn period, there is a risk of damage to 2rot seedlings.

Components of the Carbon Cycle of the Ecosystem of an Old-Growth Bilberry Spruce Forest in the Middle Taiga Subzone

Boreal forests are the most important reservoirs of terrestrial carbon. Their woody stores up to 30–35% of the total forest carbon stock, thereby making its inventory a task of national importance. In recent decades, the global practice has shifted towards scaling forest inventory data using unmanned aerial vehicles (UAVs), which are an effective and inexpensive means of collecting information at the level of individual ecosystems. The variety of survey and processing methods requires finding optimal approaches to wood stock inventory using UAVs. This article compares two methods (Matlab (ML) and TerraScan (TS)) for estimating the number, height, and projective cover of tree crowns by processing point clouds of different densities (100 and 2800 points/m2; ML100, ML2800, TS100, and TS2800). A LiDAR survey was carried out across three 50 × 50 m sample plots. SP 1: forest crossed by a stream; SP 2: forest on a flat surface; and SP 3: forest bordering an oligotrophic bog. The number of trees identified using ML100/ML2800 for SPs 1, 2, and 3 was 55/66, 67/87, and 174/220. The corresponding figures for TS100 and TS2800 were 66/95, 85/156, and 82/166, respectively. Average tree height reaches 10–24 m, with little difference between the two processing methods at each site. The total projective crown cover for SPs 1, 2, and 3 was 2569, 2494, and 2059 m2 in ML; 2091, 2424, and 1506 m2 in TS. Remote assessment enabled a reasonably complete estimation of the number of trees exclusively in the first layer: the ML100 method was sufficient for this task. However, for a more comprehensive inventory that includes lower canopy layers, the TS2800 method is preferable provided an appropriate minimum tree height value is selected.

Background. In forested regions of Russia, hundreds of thousands of hectares of forest are destroyed by wildfires every year. As a result, the success of natural forest regeneration in large-scale fire-affected areas is a relevant issue. In addition, our task was to examine how various forest types respond to wildfire and the regeneration patterns in the region. Purpose. The study was to examine forest restoration in the middle taiga of the West Siberian Plain. Material and methods. This study was carried out in the Nizhnevartovsk district of the Khanty-Mansi Autonomous Okrug (KhMAO-Yugra). 20 large-scale fire-affected areas were surveyed six years after the wildfires, covering a total area of 105.29 thousand hectares. The data for this study were collected by field surveys of fire-affected areas in pine and stone pine forests, representing the main variants of pre-fire forest growth conditions (groups of forest types). Resalts. The study showed that among conifers, Pinus sylvestris L. regenerates better. In productive pine forest types (lingonberry, green-moss, long-moss), the number of pine seedlings ranges from 11.8 to 23.4 thousand/ha. In extreme dry (lichen) and wet (sphagnum) forest types, pine regeneration is unsatisfactory. Pinus sibirica Du Tour colonizes the burnt areas primarily through the Nucifraga caryocatactes L. and the Eutamias sibiricus Laxmann. This study provided significant insights into the ecological recovery of different forest types. Stone pine regeneration can only be considered successful in green-moss stone pine forests (2.8 thousand/ha). The regeneration of deciduous trees - Betula pubescens Ehrh. and Populus tremula L. is significantly more numerous than conifers in all fire-affected areas (except for lichen types). Its quantity in productive forest types reaches 40 thousand/ha. Conclusion. In general, forest restoration is proceeding successfully in most of the surveyed fire-affected areas; more than 90% of the surveyed area can be considered forest-covered.

The article presents information on the potential, "hidden" mycobiota diversity of fallen P. abies logs in advanced decay classes (III-V). The surveys were conducted in intact native bilberry spruce forests in the middle taiga subzone within the Kivach State Nature Reserve (Republic of Karelia). The object of the study is the metagenome of fallen deadwood. Data were obtained using high-throughput sequencing (next-generation sequencing, NGS). We collected 23 mixed samples from 12 fallen P. abies logs of 3-5 th decay classes in September 2023. A total of 3461 metagenomic operational taxonomic units (mOTUs) of fungi were identified. Of these 80 % (2759 mOTUs) were identified to the species level according to NCBI: Ascomycota (1638), Basidiomycota (805), Blastocladiomycota (9), Chytridiomycota (56), Cryptomycota (2), Microsporidia (47), Mucoromycota (133), Olpidiomycota (2), and Zoopagomycota (67). The taxonomic structure of the mycobiota belonging to Ascomycota and Basidiomycota is represented down to the genus level. The composition of the mycobiota was characterized by high species diversity (Shannon index 5.0-6.2), high distribution uniformity (Pielou index 0.7-0.9) and low dominance measure values (Simpson index 0.004-0.2). The samples contained 12 fungal and 5 lichen species red-listed in the Republic of Karelia. The red-listed Ganoderma lucidum and 3 lichenized fungi Cladonia strepsilis, Dolichousnea longissima, and Gyalecta friesii, as well as one species in need of special attention to its status in the natural environment Gyalecta truncigena, were identified for the first time for this territory.

In the arboretum of the Botanical Garden at the Institute of Biology, Komi Science Centre of the Ural Branch of the Russian Academy of Sciences, we observed the development of plants of 6 Spiraeoideae taxa. They were first studied for the seasonal development features, vegetation phases, flowering and fruiting, accordance of plant rhythm to the conditions of the middle taiga subzone. The authors determined the sums of temperatures required by individual phenophases to begin. By the results of long-term phenological observations, the introduced plants go through the process of adaptation of to the climatic conditions of the North and change both terms and duration of phenological phases. The phenophases were identified to begin earlier in case of climate warming, develop in an accelerated tempo, which was especially characteristic of the shoot growth period and the flowering period. Plants of all taxa showed a completed seasonal reproductive cycle. The climate change towards its warming creates favourable conditions for a regular fruiting of tree species, which allows for both saving samples at the seed bank for a subsequent seed exchange and for growing species from seeds of local reproduction as better adapted specimens. The ongoing climatic changes create potentially more favourable conditions for both the cultivation of existing tree crops and the introduction of new cultures. The above-discussed peculiarities of the seasonal rhythm of Spiraeoideae subfamily representatives allow us to conclude about their high adaptive potential in new climatic conditions and the possibility of expanding the collection of Spiraeoideae species for introduction and application for greening purposes in the region. Keywords: SPIRAEOIDEAE, MIDDLE TAIGA SUBZONE, INTRODUCTION, BOTANICAL GARDEN, ARBORETUM, VEGETATION, FLOWERING, SEASONAL RHYTHM

Dynamic processes in indigenous spruce phytocenoses have been studied in the challenging climatic conditions of the subtundra zone, moderated by the heat brought from the south by the waters of the large Pechora River. Field material has been collected on permanent sample plots during 3 periods (2005–2006, 2013, 2022) in spruce forests of different types. The dynamics of the size structure and vitality status of woody plants in indigenous spruce forests have been analyzed based on the variability of tree stem diameters at a height of 1.3 m and the height of undergrowth. The data obtained show that with an increase in the average diameter of spruce trees in stands of subtundra spruce forests of different types, the coefficient of variation increases. The distribution of trees by absolute diameter classes is characterized by a slight stretch, usually with 1 maximum shifted to the left. In spruce forests developing on swampy-podzolic soils, most of the trees belong to small diameter classes (≤10 cm). In spruce forests of the green-moss type group, the interval of diameter classes is extended due to the presence of large trees in the stands. This dimensional structure is typical for the indigenous spruce forests of the middle taiga. The distribution of the total stand of timber by diameter classes is described as a pulsating curve with a single maximum, which, in some cases, may be interrupted at larger diameter classes. The size of the undergrowth has turned out to be more variable over time. Under the canopy of stands of subtundra spruce forests, a continuous renewal process is being observed. Stationary monitoring of the viability and damage of trees and undergrowth, based on a visual assessment of the plant by the crown, has shown an improvement in both the upper layers of the tree canopy and the lower layers of the undergrowth. The stand and undergrowth, which have been characterized as weakened at the beginning of the observation, moved into the healthy category during the monitoring period. The results of the research are part of the environmental monitoring of self-regulating spruce forests in the Pechora River basin. Long-term scientific work on permanent sample plots allows us to study the variability of plant communities and their response to global change, which contributes to a deeper understanding of the mechanisms underlying these changes, as well as ways of adapting to them. The data obtained will serve as a basis for further environmental monitoring and forecasting of the state of self-regulating Pechora forests.

In the Komi Republic, meadowsweet (Filipendula ulmaria(L.) Maxim.) (Rosaceae) grows throughout the forest zone, although less frequently in the north. Comparative studies of meadowsweet plants were conducted in two natural populations in the Syktyvdinsky District of the Komi Republic in 2020, 2022, and 2023. The first population was a grass-forb meadow in the Sokolovka tract, and the second was a grass-forb meadow on the left bank of the Sysola River. Meadowsweet flowers were collected for biochemical studies annually in the first half of July, during the period of mass budding and the beginning of flowering. Ten generative, moderately developed shoots were also selected to characterize the morphological traits of the wild plants. In 2022, the number of generative shoots was counted in triplicate in the studied natural populations, and the flower yield per 1 m² was determined. It was found that only one form of meadowsweet,F.ulmariavar.denudata, grows in the grass-forb meadows of the studied populations. Its leaves are green on both sides and glabrous underneath. The morphological characteristics of the generative shoot in both studied populations were characterized by similar indicators. The apical inflorescence on the main shoot is 8–23 cm long, can branch up to the third or fourth order and form from 264 to 1400 flowers. It was noted that per 1 m² of dense thickets ofF.ulmaria, the number of generative shoots can vary from 34 to 45. The flower yield of Filipendula ulmaria is 1,5–2,5 cm. The yield ofF.ulmariaper 1 m² was 132–190 g of raw material and 38–54 g of air-dried phytomass. It was established that the total flavonoid content in the air-dried flowers ofF.ulmaria, regardless of the weather conditions of the growing season, was high (4,3–7,8%) and was within the range of indicators for this group of biologically active substances (2,9–12,0%) in plants of natural populations ofF.ulmariain other regions of Russia. The search for and selection of the most productive populations ofF.ulmariain the middle taiga subzone of the Komi Republic is a reliable method for obtaining high-quality medicinal raw materials for the creation of new pharmaceuticals.

Relevance and objectives. Deadwood is an integral component of natural forest ecosystems, ensuring their sustainability. In Russian soil science, the role of large woody debris as a component of the soil profile is practically not taken into account, despite the fact that buried deadwood is widely represented in boreal forests. The purpose of the study is to characterize the morphological properties changes (color and soil profile structure) of illuvial-iron podzol (Ferric Albic Podzol Arenic) and gray-humus (sod) metamorphosed soil (Umbrisol Loamic) under the influence of Picea abies logs 3-5 decay classes in local conditions in the middle taiga spruce forest. Materials and methods. The study was carried out in the summer of 2023 and 2024 in the Republic of Karelia on the territory of the Kivach State Nature Reserve on two sample plots. The influence of the deadwood was studied from the 3rd to the 5th decomposition class. Soil profiles are dug in each direction from the deadwood to 1 m. The morphological description of the profile is carried out directly under the deadwood, at distances of 0-25 cm, 25-50 cm, and 50-100 cm from the log according to generally accepted methods. This work shows the influence of deadwood on the soil within a local area, and there is no extrapolation of the obtained results to the entire area of the soil type. Results. The schemes of changes in the morphological structure of the upper horizons under the deadwood trunk and at a distance from it are compiled. Under the deadwood trunks in the conditions of gray-humus soil, the AY1 horizon, intensely colored with humus, is absent. In Podzol the fermented-humus horizon OFHh is diagnosed under the log. In Umbrisol, at a distance of 25 cm from the log, a change in the composition of the forest litter is observed. In Podzol a bleached horizon E is diagnosed under the log of the last decomposition class and at a distance of up to 25 cm from it. A litter is formed directly on the fallen wood, which gradually merges with the soil litter as the log decomposes. Conclusion. Logs of 3-5 decay classes create heterogeneity in the surface horizons. The effect on morphological properties is manifested in a change in color, as well as in the appearance or, conversely, the absence of some soil horizons. The effect of log of late decay classes (classes 3, 4, 5a for Umbrisol and classes 3, 4 for Podzol) is manifested directly under the log. The effect of the log extends to the surrounding space only at the last decomposition class of the log (class 5b for Umbrisol soil and class 5 for Podzol).

This study investigates the mechanisms enabling Heracleum mantegazzianum Sommier & Levier to sustain stable population dynamics in the middle taiga subzone of European Northeast Russia without maintaining a persistent soil seed bank. Our analysis of mericarp (“seed”) viability in the soil bank, seedling recruitment patterns, and juvenile plant development demonstrates that while populations accumulate substantial quantities of empty seed coats, viable mericarp density never exceeds 2000 units/m2. The extended natural stratification period (six months) facilitates nearly complete germination of the previous year’s seed cohort during spring, resulting in the formation of only a transient seed bank under these climatic conditions. Field observations reveal remarkably consistent juvenile plant densities averaging 200 individuals/m2, maintained through three synergistic factors: reliable annual seed production, rapid spring seedling establishment, and the facultative retention of second-year plants in a juvenile growth stage. The ecological strategy of juvenile plants combines efficient seasonal light capture during spring and autumn with summer dormancy, allowing them to persist under conditions of intense intraspecific competition. H. mantegazzianum implements a sophisticated bet-hedging strategy characterized by minimal reproductive allocation (<0.01% population contribution), preservation of dormant underground meristems, and phenotypic plasticity of juvenile individuals. These integrated adaptations collectively ensure population stability despite environmental fluctuations and the evolutionary trade-off of lacking long-term seed banking capacity.

A comprehensive paleoecological study of a forested bog located in the middle taiga subzone of northeastern European Russia was carried out. According to the 14C radiocarbon dating and botanical composition analysis, the bog began forming 8200 calibrated years ago, evolving in three stages from grassy wetlands to its current state as a pine-Sphagnum peatland. Analysis revealed substantial carbon storage (81.4 kg m−2) within the peat deposit. Macrocharcoal particles were consistently present throughout the peat deposits, demonstrating continuous fire activity across the bog’s developing. High charcoal particle accumulation rates occurred not only during warm periods like the Holocene thermal maximum but also during colder and wetter periods. These periods include recent centuries, when high charcoal accumulation rates are likely due to increased human activity. Statistical analysis showed significant relationships between macrocharcoal content and several peat characteristics: higher charcoal levels correlated with increased soil carbon (r = 0.6), greater aromatic compounds (r = 0.8), and elevated polycyclic aromatic hydrocarbons (r = 0.7), all with p &lt; 0.05. These findings highlight how fire has consistently shaped this ecosystem’s development and carbon storage capacity over millennia, with apparent intensification during recent centuries potentially linked to anthropogenic influences on fire regimes in the boreal zone.