Saproxylic beetles, as primary decomposers in forest ecosystems, play a crucial role in the decomposition of dead wood. However, there is a significant gap in understanding the extent of assemblages and damage caused by these insects, which is essential for managing the quality and utilization of dead wood resources in natural forests. This study employed the Bevan damage classification system to quantify the severity of saproxylic beetle damage to fallen trees, focusing on the boreal forest in the Green zone of Ulaanbaatar, the capital of Mongolia. A factorial design was used to assess the influence of forest landscape (north vs. south mixed forest), tree species (Siberian spruce Picea obovata and Siberian pine Pinus sibirica), and decay class (1–4) on beetle damage indices, abundance and feeding guilds (cambium consumers, wood borers, predators, parasitoids, and detritivores). Our findings reveal that decay class significantly affects beetle abundance and damage severity with early stages showing the highest values. Cambium consumers and wood borers were more abundant in decay class 1 (DC1) for downed spruce, with Ips typographus (24.7%) and Tetropium castaneum (15%) causing the most damage. For the Siberian pine, Monochamus galloprovincialis (9.8%) and Judolia sexmaculata (13.3%) were the most damaging in DC1 followed by Pityogenes conjunctus (10%). The results suggest that Siberian spruce may be more susceptible to saproxylic beetle damage than the Siberian pine, with structural features such as bark cover branch size and wood moisture playing a critical role, especially in early decay stages. Based on our findings, we recommend decay-stage-specific management approaches, particularly targeting early decay stages (DC1–DC2) where beetle damage is most severe. Practical strategies include early detection of freshly downed trees, bark removal to reduce suitable habitat for cambium consumers, and on-site processing techniques such as bark gouging or mechanical debarking. These methods allow deadwood biomass to be retained in the forest while reducing pest pressure, offering a viable alternative to salvage logging. Such approaches are especially relevant in protected areas, where they can support both pest control and biodiversity conservation objectives. However, given the geographic scope limited to boreal forests of Ulaanbaatar, caution should be exercised in extrapolating these recommendations to other regions without further study.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-20452-5.

A classification of forest vegetation in the “Selbe-Goliin Ekh” Nature Reserve was conducted to identify structural features and ecological differentiation within boreal forest communities. Two associations of the class Vaccinio-Piceetea were distinguished: Carici iljinii-Pinetum sibiricae (dark-coniferous Siberian pine forests) and Vaccinio vitis-idaeae-Laricetum sibiricae (light-coniferous cowberry Siberian larch forests). The coenoflora of the first association comprises 38 species of vascular plants and lichens, while the second exhibits greater diversity with 41 species. Analysis of ecological groups revealed distinct differences between the associations. Vaccinio vitis-idaeae-Laricetum sibiricae is formed by light-demanding, drought-tolerant species adapted to nutrient-poor soils. Carici iljinii-Pinetum sibiricae is represented by shade-tolerant and moisture-loving plants favouring moderately fertile, moist substrates. Differences in the dominant functional groups reflect community adaptation to gradients of light availability, moisture, and soil nutrient status (trophicity). The obtained results underscore the role of ecological differentiation in maintaining biodiversity and the resilience of boreal ecosystems.

Destructive processes are taking place in boreal forests all over the planet, driven and catalyzed by climate change and the subsequent impact of forest pests. In Siberia, this pattern is most pronounced in Siberian stone pine forests on the southern border of the taiga zone. Taking into account the social significance of the village Siberian stone pine forests, the aim of the study has been to assess the condition of the forest cover of the Luchanovo-Ipatovsky Siberian stone pine forest in the Tomsk Region. In 2016–2017, there were 2 foci of the Siberian moth on its territory, and subsequently, stem pests have actively multiplied. A complete ground survey has been carried out on the lands of the forest area and a visual assessment of the sanitary condition of Siberian Stone pine (Pinus sibirica Du Tour) trees has been given. 21 sample plots have been laid, 45 samples of wood cores have been taken proportionally from living, shrinking and dead trees. Also, the interpretation of satellite images of the Luchanovo-Ipatovsky Siberian stone pine forest for the period from 2015 to 2023 has been carried out. It has been established that 75 % of the forest area under study is occupied by Siberian stone pine stands. The provision of undergrowth for preliminary generations is unsatisfactory. Statistical analysis has shown that stem pests have damaged trees of different generations and different diameters (p = 0.09 > 0.05 and p = 0.30 > 0.05, respectively). The course of growth with the age trend removed in groups of trees of different conditions has revealed the absence of a reliable difference in radial increment before the mass reproduction of the Siberian moth (p = 0.06 > 0.05), but it has appeared after the population outbreak (p = 0.04 < 0.05). It was the trees weakened by the Siberian moths that have been attacked by stem pests. According to our data, the total area of 2 isolated foci of the Siberian moth reproduction has been 34 ha (10 % of the total area of Siberian stone pine stands). It was in these foci that the mass reproduction of stem pests has occurred. An assessment of the disturbed areas has shown that their size is approximately 235 ha, or 70 % of the territory of Siberian stone stands. Ground-based studies have confirmed the results of space imagery interpretation, and in the medium term, a decrease in the forest-forming role of Siberian stone pine in this forest area is expected, up to the complete destruction of pure-composition stands and the ones with significant participation of Siberian stone pine in 1/2 of the current area of these stands.

New efficient broad-spectrum preparations have been developed on the basis of the aqueous solution of Novochizol with the addition of Siberian pine bark extract (SPE) and usnic acid (UA), the substance isolated from the Usnea lichen genus. Optimisation of the procedures for fungicide extraction from plant raw materials has been carried out to reduce costs and obtain pure extracts in quantities sufficient to make complex preparations. During field experiments conducted in 2022-2023 in the Novosibirsk Region, we studied the effect of seed treatment with Novochizol forms with the addition of SPE and UA on the development of root rot and leaf diseases, growth processes and yield of spring wheat Novosibirskaya 31. The use of Novochizol + UA complex as the growth regulator contributed to the reduction of root rot in the phases of tillering and milky-wax ripeness by 53.3 and 41.6 %, and Novochizol + SPE complex by 25.0 and 37.0 %, respectively. When using the seed protectant Dividend Extreme, the corresponding indicators were 70.0 and 28.6 %, respectively. The above-mentioned Novochizol + UA, Novokhizol + SPE complexes and the Dividend Extreme preparation showed effectiveness against septoria, which was 65.0, 66.7 and 67.7 %, respectively. Seed treatment had a positive growth-stimulating effect on such parameters as sprout formation, tillering, biomass accumulation, plant density, height and area of the flag leaf, and significantly improved ear structure indicators. The effect of the form of Novochizol with the addition of UA was more pronounced. Seed treatment provided an additional yield relative to the control (2.7 t/ha) at the level of 0.3 t/ha when using Novochizol + UA and 0.2 t/ha when using Novochizol + SPE or the fungicide Dividend Extreme.

To specify the region-associated mineral composition of the raw nut oil and seeds of the dwarf cedar pine (Pinus pumila) growing in an environmentally clean area of the Magadan Region, the content of 25 macro- and microelements in the raw materials was analysed. The results of the study allow us to conclude that the raw cedar nut oil is a source of the important trace elements - Zn and Cr. It has been determined that pine nuts can be considered as valuable food item because the inclusion of nuts in the diet in the amount of only 100 g can half satisfy the adult daily needs for Mg, P, Cu, Se, and Zn. This allows us to recommend raw cedar nut oil and pine seeds to be included into daily diet as a biologically active additive, which will replenish the deficiency of some vitally essential macro- and microelements for persons of any age when taken regularly in the amount not more than 1-2 teaspoons a day. No excess of the permissible levels of toxic elements in the studied samples was found, which confirms the environmental safety of the areas where the wild nut bush grows.

To investigate the genetic variation patterns of multiple traits in Pinus sibirica half_sibling families introduced to the Greater Khingan Range, this study aims to establish a comprehensive trait evaluation system based on genetic parameters and identify fast-growing, high-quality genetic materials. The findings provide scientific support for advanced-generation seed orchard development and multi-objective genetic improvement. A total of 66 half-sibling families from a 26-year-old trial plantation of the Tomsk seed source were evaluated. Eleven traits were measured, including growth traits (tree height, diameter at breast height, volume, and crown width), morphological traits (lateral branch diameter), wood quality traits (Pilodyn value), and needle traits (fresh weight, dry weight, moisture content, needle length, and needle width). Genetic parameters were estimated using variance component decomposition. Superior families with favorable performance in both growth and wood density traits were identified using Best Linear Unbiased Prediction (BLUP) weighted by genetic correlation coefficients. Additionally, individual tree selection was conducted based on growth traits using the index selection method. Significant genetic differences among families (Z ratio > 1.50) were observed for 10 traits, including growth, wood density, and needle traits. The phenotypic coefficient of variation (PCV: 5.05–62.50%) and genetic coefficient of variation (GCV: 2.19–13.81%) exhibited substantial heterogeneity. Volume displayed the highest variation (PCV = 62.50%, GCV = 13.81%), while the highest family heritability was observed for the needle length-to-width ratio (h2 = 78.30%), and the highest individual heritability was recorded for needle moisture content (H2 = 95.22%). Genetic correlations analysis revealed strong positive associations between volume and tree height (r = 0.880), diameter at breast height (r = 0.968), and Pilodyn value (r = 0.508). Using the BLUP method, 13 superior families (e.g., Families 59, 11, and 51) were identified, with an average genetic gain in volume of 13.377% and a family retention rate of 70%, significantly exceeding the population mean (65.10%). Through index selection, 94 elite individual trees were selected, 52.14% of which originated from superior families. The genetic gain in individual tree volume reached 26.80%, with the within-family gain for elite individuals increasing to 28.47%. This study establishes the first multi-trait genetic evaluation model for P. sibirica and proposes a “family-individual” collaborative selection strategy. The selected superior families achieved a volume genetic gain of 3.864–32.307% and an overall genetic gain of 2.729–20.069%, while elite individual trees exhibited a volume genetic gain of 16.328–52.716%. These findings would provide critical technical support for multi-objective breeding and seed orchard development in cold-temperate coniferous species.Graphic abstract

The article describes the planting of the most valuable tree species, Siberian cedar, using arbuscular mycorrhizal fungi, which performs not only environmental and sanitaryhygienic functions, but also has great nutritional and medicinal value for humans. The event of planting Siberian cedar seedlings on the territory of the Chkalovsky agrobiotechnopark is dedicated to the 245th anniversary of the State University of Land Management. It is planned to carry out educational and research work when growing these seedlings.

The purpose of the current work was to identify the efficiency of new biological complex products prepared on the basis of Novokhizol (NVKhZ) with chitosan and Siberian pine bark extract (SPBE) in protecting spring common wheat from root rot and obligate pathogens (powdery mildew, brown rust) in the forest-steppe of the Ob region, and also to establish their effect on yield elements. The trials were carried out with the spring wheat variety ‘Novosibirskaya 29’ in the field of SibNIISR – branch of the ICG SB of RAS (Novosibirsk) in 2023–2024. The method of application of the products was pre-sowing seed treatment and treatment of vegetative plants. There has been established an efficiency of NVKhZ + SPBE against common root rot. The development of the disease on the roots on average over two years decreased from 21.5 to 3.95 %, the biological efficiency of the product was 81.7 %. There has been found that the use of biological products on vegetative plants reduced the damage of plants by obligate pathogens more than pre-sowing seed treatment. Seed treatment with products contributed to an increase in plant height by 8.7 % with NVKhZ + Chitosan and by 6.8 % with NVKhZ + SPBE, root length by 36.3 % with NVHZ + Chitosan, by 22 % with NVKhZ + SPBE and plant biomass by 17.6 %. There has been found a positive effect of Novochizol compositions on the formation of productive stems, a length of the main spike, a number of kernels per main spike, and kernels per plant. There has been established and statistically proved a positive effect of the tested products on crop yields. On average, over the years of study, plant productivity in variants with biological products has exceeded control values by 1.2 times.

Mono- and sesquiterpenoid fingerprinting: A powerful and streamlined solution for pine nut authentication.

Effects of ammonia vapor and tannin treatments were studied relative to the properties of wood. The color change, surface roughness, and surface hydrophobicity of Persian oak (Quercus persica), Persian walnut (Juglans regia L.), Oriental beech (Fagus orientalis Lipsky), and Siberian pine (Pinus sibirica) were evaluated after treatments for 8 and 24 h. The color difference (ΔE*) values increased with prolonged exposure, with the highest changes observed in tannin-treated samples exposed to ammonia vapor for 24 h. Pronounced color changes were observed in Siberian pine samples, while beech and oak showed moderate color shifts. Walnut exhibited a more complex response, with an initial increase in yellowness followed by stabilization. Surface roughness measurements demonstrated a significant increase, particularly in maximum height (Rz), indicating substantial modifications to the wood surface. The most significant increase in roughness was observed in the samples treated with ammonia vapor and tannin after 24 hours of exposure, regardless of species type, although oak and walnut showed more controlled alterations. The surface hydrophobicity of the samples was increased after treatment, with the highest contact angle values after treatment for 24 h. This study highlights the potential of tannin and ammonia vapor treatments for improving the aesthetical and surface properties of wood.

Приведены результаты исследования состояния 44-летних лесных культур сосны кедровой сибирской, произрастающих в лесостепной зоне Тюменской области, в условиях дендрария Сибирской лесной опытной станции (ЛОС) города Тюмень. Изучение состояния древостоя проведено на двух временных пробных площадях (ВПП), заложенных на участках с разной схемой размещения деревьев. Деревья на участке 1 (ВПП-1) высажены по схеме 4х4 метра, на участке 2 (ВПП-2) – со схемой посадки 2,5х1 метр. Установлено, что древостой кедра сибирского на участке со схемой размещения деревьев 4х4 м является среднеполнотным, растущим по II классу бонитета, при схеме посадки 2,5х1 м – высокополнотный и характеризуется III классом бонитета. Наименьшими таксационными параметрами характеризуется древостой на участке 2 (ВПП-2) со схемой размещения 2,5х1 м. Значения средней высоты и диаметра на высоте 1,3 м на 20-35% меньше в сравнении с аналогичными показателями на участке 1 (ВПП-1) при схеме размещения 4х4 м. Полученные различия основных таксационных показателей статистически значимы. По показателям санитарного и жизненного состояния лесные культуры кедра сибирского на участке 1 характеризуются как здоровые, на участке 2 – ослабленные. Сухостойные деревья в количестве 2% от общего числа деревьев зафиксированы только на ВПП–2. Количество здоровых по состоянию деревьев на участке со схемой посадки 4х4 м в 1,8-3 раза больше в сравнении с участком со схемой посадки 2,5х1 м. При этом, количество ослабленных, сильно ослабленных и отмирающих деревьев, в среднем, в 1,5-4 раза меньше. По показателю относительной высоты (H/D) древостой на участке 1 (ВПП-1) характеризуется как биологически устойчивый. На участке 2 с более загущенным произрастанием деревьев кедра сибирского, значение относительной высоты которых больше 100 (H/D>100), составляет, в среднем, 15% от общего количества деревьев на ВПП. По полученным данным можно рекомендовать сосну сибирскую кедровую для плантационного выращивания в защитных лесах в условиях лесостепной зоны Тюменской области со схемой посадки 4х4 метра. The article provides the results of the analysis of the state of 44-year-old Siberian stone pine forest growing in the forest-steppe zone under the arboretum conditions of the Siberian Forest Experimental Station of the city of Tyumen. The study of the state of pine stands on the two temporary sample plots (TSP) with different tree planting patterns was carried. The trees on TSP -1 were arranged according to the 4x4 meter pattern, on TSP-2 – with a 2.5x1 meter planting pattern.. It was founded that the Siberian stone pine stand on TSP-1 was medium stocked, growing according to the II productivity class, in the case of the TSP-2 the stand was fully stocked and was characterized by the III productivity class. The TSP-2 stand was featured by the lowest taxation specifications. Indices of the average height and diameter at 1.3 m level were 20-35% less if compare with the same indices of the stand on TSP-1. The obtained differences of the main pine stands taxation indicators are statistically significant. According to the indicators of sanitary and vital state, Siberian stone pine forest crops on the site 1 were considered as healthy ones, on site 2 – as weakened. Dead standing trees amounted 2% of the their total number were located on TSP-2 only. The number of healthy trees on a plot with a 4x4 m planting pattern was 1.8-3 times higher compared to a plot with a 2.5 x 1m planting pattern. At the same time, the quantity of weakened, severely weakened and dying trees was on average 1.5-4 times less. According to a tree slenderness coefficient (H/D), the stand on TSP-1 is considered as biologically stable. On TSP-2, with more dense trees stand, with index of slender coefficient that was more than 100 (H/D>100), constituted on average, 15% of total number of trees on a TSP. Based on the data obtained, Siberian stone pine (Pinus sibirica Mayr.) can be recommended for plantation growth in protective forests under the forest-steppe zone of the Tyumen region with a planting pattern of 4x4 meters.

Organoleptic analysis provides an understanding and assessment of human perception of food product characteristics, while there is a limited number of studies aimed at creating organoleptic methods for assessing the quality of processed natural honey and Siberian pine seeds. The objectives of the work are to create a dictionary of organoleptic indicators of honey-cedar syrups and to develop a scoring system for organoleptic assessment of honey-cedar syrups. Objects of research: Siberian pine seed kernels and semi-finished products from them, natural flower honey, and experimental samples of honey-cedar syrups. The authors used standard organoleptic and statistical methods to achieve the goals. As a result of the research, the initial list of descriptive characteristics of honey-cedar syrups was reduced from 127 to 13 descriptors – appearance and texture (viscosity, homogeneity), color (brown, uniform), aroma (honey, nutty), taste and aftertaste (sweet, rich, honey, nutty, floral, tart, long aftertaste). A five-point system of organoleptic assessment of products has been developed taking into account the developed dictionary, in which the weight coefficient of the indicator (appearance and texture, color, aroma, taste and aftertaste - respectively 0.25; 0.15; 0.20 and 0.40) is multiplied by a point (if non-conformity is established – by the lowest). The points obtained for each indicator are summed up and the quality level is determined: excellent – above 4.4 points; good – 3.7–4.4 points; satisfactory – 2.9–3.69 points; unsatisfactory – below 2.9 points. As a result of the validation of the scoring system, the experimental samples of honey-cedar syrups with different ratios of natural honey and semi-finished product from cedar pine seed kernels were ranked by quality levels as follows: excellent– sample 60:40 (4.68 points) > sample 55:45 (4.6 points) > sample 65:35 (4.48 points); good – sample 70:30 (4.32 points). The scoring system for organoleptic evaluation of honey-cedar syrup is a means of communication between stakeholders at various stages of the product life cycle.

The purpose of the research is to investigate the resistance of Pinus sylvestris, P. sibirica and Larix sibirica pine seedlings to the nematode Bursaphelenchus xylophilus to assess the potential risk of death of these conifers from pine wilt disease.Materials and methods. In the experiment, 8-year-old seedlings of P. sylvestris, P. sibirica and 4–5-year-old seedlings of L. sibirica were used in an amount of 16 seedlings of each species (8 B. xylophilus-infected plants and 8 control plants).Results and discussion. Pines Pinus sylvestris, P. sibirica and L. sibirica were susceptible to the pine wood nematode B. xylophilus. All plants died by the end of the study, but the most rapid wilting and death of plants was observed in Siberian larch seedlings. More intensive nematode reproduction was recorded in P. sibirica, with seedlings dying later than other plants. The preliminary analysis showed that the death of conifer stands of the studied species from pine wilt disease is possible in the climatic zone of Siberia.

Lignin-carbohydrate complex reaction to fungus infection in Siberian pine tree rings

Abstract. Solid fuel (SF) combustions, including coal and biomass, are important sources of pollutants in the particle and gas phase and therefore have significant implications for air quality, climate, and human health. In this study, we systematically examined gas-phase emissions, using the Vocus proton-transfer-reaction time-of-flight (PTR-TOF) mass spectrometer, from a variety of solid fuels, including beech logs, spruce/pine logs, spruce/pine branches and needles, straw, cow dung, and coal. The average emission factors (EFs) for organic vapors ranged from 4.8 to 74.2 g kg−1, depending on the combustion phases and solid fuel types. Despite slight differences in modified combustion efficiency (MCE) for some experiments, increasing EFs for organic vapors were observed with lower MCE. The relative contribution of different classes showed large similarities between the combustion phases in beech logs stove burning, relative to the large change in EFs observed. The CxHyOz family is the most abundant group of the organic vapor emitted from all SF combustion. However, among these SF combustions, a greater contribution of nitrogen-containing species and CxHy families (related to polycyclic aromatic hydrocarbons) is observed in the organic vapors from cow dung burning and coal burning, respectively. Intermediate-volatility organic compounds (IVOCs) constituted a significant fraction of emissions in solid fuel combustion, ranging from 12.6 % to 39.3 %. This was particularly notable in the combustion of spruce/pine branches and needles (39.3 %) and coal (31.1 %). Using the Mann–Whitney U test on the studied fuels, we identified specific potential new markers for these fuels based on the Vocus measurements. The product from pyrolysis of coniferyl-type lignin and the extract of cedar pine needle were identified as markers in the open burning of spruce/pine branches and needles (e.g., C10H14O2, C11H14O2, C10H10O2). The product (C9H12O) from the pyrolysis of beech lignin was identified as the potential new marker for beech log stove burning. Many series of nitrogen-containing homologues (e.g., C10H11–21NO, C12H11–21N, C11H11–23NO, and C15H15–31N) and nitrogen-containing species (e.g., acetonitrile, acrylonitrile, propanenitrile, methylpentanenitrile) were specifically identified in cow dung burning emissions. Polycyclic aromatic hydrocarbons (PAHs) with 9–12 carbons were identified with significantly higher abundance from coal burning compared to emissions from other studied fuels. The composition of these organic vapors reflects the burned solid fuel types and can help constrain emissions of solid fuel burning in regional models.

The indicators of undergrowth accumulation in the felling sites of the West Siberian north taiga lowland forest area have been analyzed. The undergrowth has been recorded on the plots measuring 2×2 m in the amount of 30 plots on each studied felling site. It is noted that reforestation in the study area is proceeding quite successfully. In the conditions of green moss-berry and wild rosemary-lingonberry forest types, the undergrowth includes Scots pine (Pinus sylvestris L.), silver (Betula pendula Roth.) and downy (B. рubescens Ehrh.) birch, Siberian stone pine (Pinus sibirica Rupr.), aspen (Populus tremula L.), Siberian spruce (Picea obovata Ledeb.) and Siberian larch (Larix sibirica Ledeb.) with the dominance of Scots pine and silver birch. The high proportion of birch is explained by the annual seed production of the species and the transfer of seeds by wind over long distances, as well as its ability to vegetatively renew. The regeneration of coniferous species is inhibited by the periodicity of seed years, the suspension of seeds in the forest litter and moss thalli. These problems can be solved by soil mineralization. It is better to combine mineralization with the clearing of felling sites from felling residues. The latter are bulldozed onto a skidding trail from 2 sides. As a result of mixing the felling residues with the forest litter and soil, wood destruction processes are activated and the fire hazard at the felling site is minimized, and ideal conditions for the accumulation of undergrowth are created. The main area between the skidding trails (65–70 %) remains without mineralization, since in this part of the felling site, the maximum amount of pre-generation undergrowth is preserved during logging operations. In the conditions of the northern taiga subzone of the Khanty-Mansy Autonomous Okrug – Yugra, where the average wood increment is 0.6 m3/ha, the raw material value of the stands gives way to the ecological value. Considering the important ecological role of silver and downy birch, it is advisable to establish them as the main tree species. This will speed up the transfer of felling sites to forested lands and reduce an unreasonably high proportion of the forest culture fund area.

Genetic Diversity and Differentiation of Siberian Stone Pine (Pinus sibirica Du Tour) Populations from the Cis-Urals and Urals

The frequency of wildfires ignited by lightning is increasing due to global climate change. Since the forest ecological recovery is influenced by numerous factors, the process of post-fire vegetation recovery in Siberian dwarf pine shrublands remains unclear and demands in-depth study. This paper explored the short-term recovery process of vegetation after two lightning-ignited fires in the Great Xing’an Mountains that occurred in 2017 and 2020, respectively. The study was aimed at presenting a monitoring approach for estimating the post-fire vegetation state and assessing the influence of various driving factors on vegetation recovery. Spectral indices were computed to evaluate forest vegetation recovery dynamics. The differences in vegetation recovery under various fire severity and topography conditions were also examined. Correlation analysis was employed to assess the influence of moisture content on the recovery of fire sites. The results show that fire severity, topographic features, and moisture content significantly impacted the rate of vegetation recovery. Specifically, regeneration takes place more rapidly on warm, high-altitude, and gentle slopes within highly and moderately burned areas. Additionally, areas marked by high moisture content demonstrate rapid recovery. Our study enriches the research cases of global wildfires and vegetation recovery and provides a scientific basis for forest management and the restoration of post-fire ecosystems.

Tree-ring width chronologies of Pinus sibirica Du Tour from near the upper treeline in the Western Sayan, Southern Siberia are found to have an exceptional (below mean-3SD) multi-year drop near 1700 CE, highlighted by the seven narrowest-ring years in a 1524-2022 regional chronology occurring in the short span of one decade. Tree rings are sometimes applied to reconstruct seasonal air temperatures; therefore, it is important to identify other factors that may have contributed to the growth suppression. The spatiotemporal scope of the "nosedive" in tree growth is investigated with a large network of P. sibirica (14 sites) and Larix sibirica Ledeb. (61 sites) chronologies, as well as with existing climatic reconstructions, natural archives, documentary evidence (e.g., earthquake records), and climate maps based on 20th-century reanalysis data. We conclude that stress from low summer temperatures in the Little Ice Age was likely exacerbated by tree damage associated with weather extremes, including infamous Mongolian "dzuds", over 1695-1704. A tropical volcanic eruption in 1695 is proposed as the root cause of these disturbances through atmospheric circulation changes, possibly an amplified Scandinavia Northern Hemisphere teleconnection pattern. Conifer tree rings and forest productivity recorded this event across all of Altai-Sayan region.

In the southern taiga of Siberia, periodic outbreaks of the Siberian moth Dendrolimus sibrircus Tschetv. have been observed. The outbreaks result in the defoliation of Siberian fir Abies sibirica Ledeb. and Siberian pine Pinus sibirica Du Tour. stands across approximately one million hectares, leading to dieback of the affected forests. This is largely attributable to the inability to promptly identify the onset of the pest population growth in a timely manner, particularly in the context of expansive forest areas with limited accessibility. It is feasible to enhance the efficacy of monitoring Siberian moth populations by discerning stands with the highest propensity for damage and concentrating efforts on these areas. To achieve this, we employed machine learning techniques, specifically gradient boosting, support vector machines, and decision trees, training models on two sets of predictors. One of the datasets was obtained through a field study conducted in forest stands during the previous outbreak of the Siberian moth (2015–2018), while the other was derived from the analysis of remote sensing data during the same period. In both 2015 and 2016, the defoliation was most accurately predicted using gradient boosting (XGB algorithm), with ROC-AUC values reaching 0.89–0.94. The most significant predictors derived from the ground data were the proportions of Siberian fir, Siberian spruce Picea obovata Ledeb., and Scots pine Pinus sylvestris L., phytosociological data, tree age, and site quality. Among the predictors obtained from the analysis of remote sensing data, the distance to disturbed forest stands was identified as the most significant, while the proportion of dark coniferous species (A. sibirica, P. sibirica, or Picea obovata Ledeb.), the influx of solar radiation (estimated through the CHILI index), and the position in the relief (mTPI index) were also determined to be important.