Larch Species Research Articles

The age and genetics of individual larches in four rural parks and at the Järvselja Educational and Experimental Forest Centre in Estonia

Abstract The article investigates the historical presence and current status of larch trees within the parks of five former manors in South Estonia: Kastre and its Peravalla forest district (now Järvselja Educational and Experimental Forest Centre), Mäksa, Kabina and Mõniste. Before 1918, South Estonia was part of the province of Livonia in the Russian Empire. The analysis encompasses taxonomy, habitats and the introduction of various larch species. Selected larch trees within these parks were dated using dendrochronological methods. The research revealed a consistent pattern of larch tree planting over a century, occurring in seven distinct rounds between the 1820s (Kastre Park) and the 1940s (Järvselja) as follows: 1) 1820 and 1895 (Kastre), 2) 1907 and 1920–1940 (Järvselja), 3) 1825–1840 (Mõniste), 4) 1855–1865 (Kabina), and 5) 1870–1880 (Mäksa). Genetic characterization was applied to determine individual tree species based on morphometric determinations. The majority of larch trees within the parks were genetically confirmed as European larches, which was consistent to the morphological assessments conducted at Kastre, Järvselja and Mäksa. The analysis revealed that a younger, naturally propagated larch located at Kastre with morphological characteristics of European larch showed subtle genetic indicators of Japanese larch. The cause of this unexpected finding remains vague. It is hypothesized that this specific tree might represent a hybrid of European and Siberian larches, given its inclusion within a stand hosting both species in proximity. At Järvselja, the genetic method confirmed the morphological identification of four larches as Japanese and two as Dunkeld larches. Six Siberian larches (sensu lato) located at Kastre and Järvselja were genetically identified as hybrids of Japanese and European larches while the cause of this hybridization remains unclear. Utilization of genetic markers not validated for Russian (L. archangelica), Siberian (L. sibirica s. str.), and hybrid (L. decidua × L. sibirica and L. sibirica × L. decidua) larches makes the obtained results inconclusive. In the case of Mäksa, both morphological and genetic analyses confirmed the presence of Japanese and Euro-Japanese larches, which was previously confirmed. It is important to note that the classification of L. leptolepis × L. decidua proposed by Bobrov is considered incorrect. Trees displaying similar characteristics, especially older specimens, should be classified according to Bobrov’s description as L. decidua f. kaempferi or f. marschlinsii.

Evaluation on the Efficacy of Farrerol in Inhibiting Shoot Blight of Larch (Neofusicoccum laricinum).

Neofusicoccum laricinum is the causal agent of larch shoot blight, a fungal disease affecting several species of larch. It causes severe damage, including stunting and mortality. This study aims to address the severe impact of larch shoot blight by evaluating the effect of farrerol on the inhibition of Neofusicoccum laricinum in Larix olgensis. We used LC-MS/MS and weighted gene co-expression network analysis to investigate farrerol's effects on Neofusicoccum laricinum and identify associated genes in resistant and susceptible larch. Our study identified significant differences in metabolite profiles between resistant and susceptible cultivars, with higher concentrations of farrerol showing complete inhibition of N. laricinum. Additionally, specific genes associated with farrerol content were up-regulated in resistant larch. Farrerol at higher concentrations completely inhibited N. laricinum, showing a strong correlation with increased disease resistance. This research suggests that farrerol enhances disease resistance in larch and provides a foundation for developing disease-resistant larch varieties based on antifungal metabolite traits.

A comparison of the early growth and survival of lesser-known tree species for climate change adaptation in Britain

Globally, climate change is altering both seasonal climates and the occurrence of extreme climate events, resulting in a drive to ensure our forests are resilient to these changes and the challenges they will bring. In Great Britain (GB), there has been a reliance on a limited number of species grown in monospecific plantations and concerns over the resilience of these forests is leading to a growing recognition of the need to diversify tree species composition. However, evidence of the relative growth rate and survival of alternative tree species and provenances during the critical establishment phase (typically within five or six years of planting) is often limited, hampering consideration of the wider adoption of many potentially suitable species. To address this knowledge gap, we compared tree height and survival data six years after planting from 34 provenances across 18 tree species at five experimental sites established across GB in 2012 in monospecific plots. For coniferous species, we found that Larix decidua, Larix x marschlinsii and Pinus radiata (on drier sites) were consistently amongst the tallest species, but survival could be variable. Pseudotsuga menziesii and Pinus pinaster also showed good early growth, matching the growth rate of Picea sitchensis (the most widely planted conifer in GB) when co-occurring and often exhibited good survival. In contrast Picea orientalis was slow to establish and amongst the smallest species at all five sites after six years, with Cedrus atlantica also performing poorly where planted. Surprisingly, we found very few differences in both mean tree height and survival between most provenances of the same species across all experimental sites, though more obvious differences may emerge as these trees mature. Only a small number of broadleaf species were available for analysis at age six in this study, but as expected Betula pendula generally performed well, while Acer macrophyllum often had very high mortality. While there are concerns around the susceptibility of pine species to Dothistroma septosporum and the future use of larch species in GB forestry is currently limited by the disease Phytophthora ramorum, our results highlight the potential for these species to establish well and exhibit good initial growth and survival on drier sites, with the same true of P. menziesii on moister sites. Future work should aim to understand whether further differences between species and provenances emerge with age and explore the potential of these emerging species as components of mixed-species stands to increase GB forest resilience to climate change.

Antennal Transcriptome Screening and Identification of Chemosensory Proteins in the Double-Spine European Spruce Bark Beetle, Ips duplicatus (Coleoptera: Scolytinae).

The northern bark beetle, Ips duplicatus, is an emerging economic pest, reportedly infesting various species of spruce (Picea spp.), pine (Pinus spp.), and larch (Larix spp.) in Central Europe. Recent climate changes and inconsistent forest management practices have led to the rapid spread of this species, leaving the current monitoring strategies inefficient. As understanding the molecular components of pheromone detection is key to developing novel control strategies, we generated antennal transcriptomes from males and females of this species and annotated the chemosensory proteins. We identified putative candidates for 69 odorant receptors (ORs), 50 ionotropic receptors (IRs), 25 gustatory receptors (GRs), 27 odorant-binding proteins (OBPs), including a tetramer-OBP, 9 chemosensory proteins (CSPs), and 6 sensory neuron membrane proteins (SNMPs). However, no sex-specific chemosensory genes were detected. The phylogenetic analysis revealed conserved orthology in bark beetle chemosensory proteins, especially with a major forest pest and co-habitant, Ips typographus. Recent large-scale functional studies in I. typographus chemoreceptors add greater significance to the orthologous sequences reported here. Nevertheless, identifying chemosensory genes in I. duplicatus is valuable to understanding the chemosensory system and its evolution in bark beetles (Coleoptera) and, generally, insects.

Pathogenicity and induced resistance in Larix kaempferi and Larix olgensis inoculated with Endoconidiophora fujiensis.

With climate warming and economic globalization, insect-microbe assemblages are becoming increasingly responsible for various devastating forest diseases worldwide. Japanese larch (Larix kaempferi) is extensively cultivated in China because of its high survival rate, rapid maturation and robust mechanical properties. Endoconidiophora fujiensis, an ophiostomatoid fungus associated with Ips subelongatus, has been identified as a lethal pathogen of L. kaempferi in Japan. However, there is a dearth of research on the pathogenicity of E. fujiensis in larches in China. Therefore, we investigated the pathogenicity of E. fujiensis in introduced L. kaempferi and indigenous larch (Larix olgensis) trees and compared the induced resistance responses to the pathogen in both tree species in terms of physiology and gene expression. Five-year-old saplings and 25-year-old adult trees of L. olgensis and L. kaempferi were inoculated in parallel during the same growing season. Endoconidiophora fujiensis exhibited high pathogenicity in both larch species, but particularly in L. kaempferi compared with L. olgensis adult trees; adult L. olgensis was more resistant to E. fujiensis than adult L. kaempferi, which was reflected in higher accumulation of defensive monoterpenes, such as myrcene, 3-carene and limonene and the earlier induction of defense genes catalase (CAT) and pathogenesis-related protein 1 (PR1). This study contributes to our understanding of the interactions between bark beetle-associated ophiostomatoid fungi and host larches, from phenotypic responses to alterations in secondary metabolites via defense- and metabolism-related gene activation, providing a valuable foundation for the management of larch diseases and pests in the future.

Siberian Pine and Larch Response to Warming-Drying Climate in the Southern Boundary of Their Range

Trees’ growth and areal responses to changing climate are primarily expected within the edges of the species range. Here, we compared the responses of Siberian pine (Pinus sibirica Du Tour), a moisture-sensitive species, and drought-resistant larch (Larix sibirica Ledeb.) at the southern part of their ranges in the Siberian Mountains (the Tannu-Ola Ridge). We study the species’ growth and proportion in the forests from forest-steppe to treeline ecotone along the elevation gradient. These studies are based on radial growth index (GI) analysis and GI dependence on the climate variables. We used satellite time series to detect the land cover changes (areas of larch and Siberian pine, as well as shrubs and birch). We compared trees’ GI before and after warming “restart” in the late 1990s. Generally, GI dependence on the air temperature was negative at elevations below c. 1600 m a.s.l., whereas GI dependence on the moisture variables (precipitation, vapor pressure deficit, and soil moisture) was positive for both species. Above 1600 m, increasing air temperatures stimulated species growth, whereas the influence of moisture variables was negative (for larch) or neutral (for Siberian pine). After the warming restart, the GI of both conifers increased in moisture-sufficient high elevations and treeline ecotone, whereas within low elevations (<1300 m), the GI was stagnant or suppressed. Both species’, especially Siberian pine, negative growth dependence on air temperature and positive dependence on the moisture variables strongly increased since the warming restart. We found a risen growth dependence of both species on the soil-stored water during the previous year (September–October), which smoothed moisture stress at the beginning of the growing season. Yet both species’ growth also suffered as a result of early spring warms. We found that larch is migrating in both uphill and downhill directions, while Siberian pine is migrating uphill only. Forests loss occurred at low elevations (<1300 m), whereas forest and shrub gain occurred at high (>2000 m) ones. The upper boundary of the forests and shrubs is migrating uphill at rates of about 0.8 and 0.3 m/y, respectively. We observed a decrease in Siberian pine proportion in the forests, whereas areas of larch and birch strongly increased (by 150% and 100%, respectively), which indicates the retreat of Siberian pine from its southern habitat. We suggested afforestation of the areas of Siberian pine mortality by the drought-tolerant larch species.

Perspectives on Using Alder, Larch, and Birch Wood Species to Maintain the Increasing Particleboard Production Flow.

Particleboard, engineered wood products as part of a large family of wood composite materials, developed in use mainly in the 1950s and 1960s to utilize inferior wood and wood waste when good-quality wood was in short supply; the annual production capacity worldwide is over 100 million m3. It is also necessary to have a lot of wood raw material for its production, although raw material resources are limited on our planet. In addition to the main wood species, it is therefore possible to think about the wider use of alternative, lesser-known European species of alder, larch, and birch in particleboard production. These three wood species represent an eco-friendly and sustainable wood alternative to the conventional wood raw materials used. This review confirms the diversity of the use of these three species in different fields and proves their suitability in relation to particleboard production. Fundamental research is ongoing in certain universities to determine the proportional shares of use of these tree species in particleboard (in a certain weight proportion in their core layers) for the purpose of formulating the correct technology shares and rules for their application in the wood-based panel industry.

First record of Adelges (Cholodkovskya) viridanus (Hemiptera: Adelgidae) in North America, with a description of the fundatrix form in Japan

AbstractAdelges (Cholodkovskya) viridanus (Cholodkovsky 1896) (Hemiptera: Adelgidae) is found throughout Eurasia where it is understood to be anholocyclic, feeding on species of larch (Larix), without host alternation. For the first time, we report this species in North America, outside of its native range, from specimens collected in an arboretum in Ohio, USA. Molecular phylogenetic analysis was inconclusive as to whether it was introduced from Europe or Asia. In addition, specimens collected from Picea jezoensis in Japan were confirmed for the first time as A. (C.) viridanus by matching DNA sequences to specimens collected on Larix. Therefore, A. (C.) viridanus is either capable of completing a host‐alternating holocycle in Japan, or includes very recently diverged anholocyclic populations on Picea. Finally, we describe the adult fundatrix form, which was previously unknown.

Интродукция кедра и лиственницы в условиях Кольского Заполярья

The purpose of this study was to investigate the history of growth of the introduced species Pinus sibirica Du Tour and Larix sibirica Ledeb. in the Murmansk region and their state in natural areas of preferential protection. The first finds of Siberian cedar in the Arctic region were recorded in 1911, and Siberian larch in 1925. In the 1930s and 1950s–1960s, these kinds of trees were extensively cultivated in the region. Many cedar and larch growth areas are protected as natural monuments of regional significance. Currently, there are eight natural monuments with Siberian cedar growing on the territory of the Murmansk region and seven natural monuments with Siberian larch. The condition of the trees in the territories under preferential protection and the Lapland State Natural Biosphere Reserve was studied in detail. The invasive species occupy a territory of about 70 ha. It was a complete or random enumeration of the trees and undergrowth with measurements of height and diameter. Siberian cedar ranged in height from 0.02 to 18.00 m, whereas Siberian larch was between 0.01 and 18.00 m. Cedar diameters varied from 0.3 to 31.7 cm, whereas larch diameters ranged from 0.4 to 38.3 cm. It is shown that coniferous introduced species are well acclimatized to the natural conditions of the Arctic, which increases the biodiversity of ecosystems and aesthetic perception. Pinus sibirica Du Tour and Larix sibirica Ledeb. fructify in the conditions of the Kola Arctic region that is a sign of a natural regeneration. It is recommended to monitor the conditions of the plantations on a regular basis in order to provide appropriate care. With the inclusion of plots with the growth of the studied species in natural areas of preferential protection, it is necessary to study their condition, location, accessibility, and targeted application. Evaluation of the effectiveness of existing forest management system will allow a more rational approach to the conservation of valuable cedar and larch tree species in the Arctic region. For citation: Isaeva L.G., Ershov V.V., Urbanavichus G.P., Borovichev E.A. Introduced Species of Cedar and Larch in the Climate Conditions of the Kola Arctic Region. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 4, pp. . 41–57. (In Russ.). https://doi.org/10.37482/0536-1036-2023-4-41-57

A nature reserve as a repository of genetic richness – The case of European larch from the Gorce Mountains

Conservation of valuable populations must be based on a thorough understanding of their genetic variation, especially for species negatively affected by human activities. We investigated the population of larch from the nature reserve in the Gorce Mountains, which was established to preserve a unique stand of Larix decidua subsp. polonica, a remnant of one of the largest native complexes of this species. The chloroplast marker ll-TaqI was used to investigate whether the gene pool of the analysed population was contaminated with the alien larch species. We used eleven nuclear DNA microsatellite markers (nSSRs) to examine this population’s genetic diversity and verify the hypothesis about historical use of the larch from the reserve as a source of reproductive material for the Tatra Mountains. The link between the reserve population and the European larch’s ancestral groups was also verified. No contamination of the studied pool of individuals by alien species was found. The study showed high genetic variability in larch from the Gorce Mountains (HE = 0.689, HO = 0.671). The differentiation between the Gorce and Tatra National Park populations was FST = 0.038 (p < 0.001). Trees from the reserve and the national park formed two distinct genetic groups. We rejected the hypothesis that the nature reserve was the source of the regeneration material used in the Tatra Mountains. The study proved the uniqueness of the reserve population, and confirmed the appropriateness of the protection measures taken.

Automated Segmentation of Individual Tree Structures Using Deep Learning over LiDAR Point Cloud Data

Deep learning techniques have been widely applied to classify tree species and segment tree structures. However, most recent studies have focused on the canopy and trunk segmentation, neglecting the branch segmentation. In this study, we proposed a new approach involving the use of the PointNet++ model for segmenting the canopy, trunk, and branches of trees. We introduced a preprocessing method for training LiDAR point cloud data specific to trees and identified an optimal learning environment for the PointNet++ model. We created two learning environments with varying numbers of representative points (between 2048 and 8192) for the PointNet++ model. To validate the performance of our approach, we empirically evaluated the model using LiDAR point cloud data obtained from 435 tree samples scanned by terrestrial LiDAR. These tree samples comprised Korean red pine, Korean pine, and Japanese larch species. When segmenting the canopy, trunk, and branches using the PointNet++ model, we found that resampling 25,000–30,000 points was suitable. The best performance was achieved when the number of representative points was set to 4096.

Colour Modification of Wood by Dry Thermal Treatment between 90 °C and 200 °C

The colour modification effect of dry thermal treatment was studied in black locust (Robinia pseudoacacia L.), poplar (Populus x euramericana cv. Pannonia), Scots pine (Pinus sylvestris L.), spruce (Picea abies Mill.) and larch (Larix decidua L.) species in the temperature range 90-200 °C. Colour data were presented and evaluated in the CIE L*a*b* coordinate system. All thermal treatments applied altered the wood colour throughout the entire cross section regardless of the treatment temperature. At lower temperatures, wood extractives played a decisive role in colour change. The degradation products of hemicelluloses were the major determinant of the change in lightness at 200°C. Redness change in percentage showed much greater alteration than the yellowness and the lightness change. Spruce presented the greatest chromaticity coordinate (a* and b*) alteration among the investigated species. Changes in redness and yellowness followed the Arrhenius law during the investigated dry thermal treatments confirming that the temperature dependence of these colour parameters is exponential for wood material.

Интродукция климатипов лиственницы европейской в зоне смешанных лесов

The range of European larch (Larix decidua Mill.) covers Central Europe, while in Podmoskovie this species grows out of its natural distribution area. In plantings this species is known for its fast growth, stability, good soil and water protection properties, and high wood quality. All larch species in the Moscow region have a positive reputation in terms of high adaptability, they are often more productive than the local coniferous forest-forming species. Similar results were obtained by foresters in Central and Eastern Europe. The increment in stock in a number of Polish larch populations at the age of 50–60 years can reach 10–15 m3/ha per year, that is why this wood species is widely used in silvicultural practice in these countries. The research aims at studying the growth and productivity of European larch climatypes outside its natural habitat. The research covered experimental sites of European larch introduction located in the territory of the center of the Russian Plain within the Moscow region. Of all the European larch climatypes, the Polish larch has the highest growth rates in height and diameter, as well as in the accumulation of trunk stock. It forms stands with very large trunks and has an increased value of soil-light basic increment in diameter of the trunks. The Polish larch is superior to the European larch of Sudeten origin in terms of silvicultural effect. As a result, Polish larch has undeniable advantages among all the reviewed provenances in terms of growth rate and accumulation of trunk wood reserves, which is a strong argument in the issue of its expanded introduction as a promising conifer for target reforestation. European larch from Scotland has the worst growth and productivity. On the whole, all climatypes of European larch successfully adapt to the conditions of the center of the Russian Plain and are superior to all local coniferous forest-forming species in terms of inventory characteristics.

Comparative transcriptomic responses of European and Japanese larches to infection by Phytophthora ramorum

Background and objectivesPhytophthora ramorum severely affects both European larch (EL) and Japanese larch (JL) trees as indicated by high levels of mortality particularly in the UK. Field observations suggested that EL is less severely affected and so may be less susceptible to P. ramorum than JL; however, controlled inoculations have produced inconsistent or non-statistically significant differences. The present study aimed to compare RNA transcript accumulation profiles in EL and JL in response to inoculation with P. ramorum to improve our understanding of their defence responses.MethodologyRNA-sequencing was carried out on bark tissues following the inoculation with P. ramorum of potted saplings in both EL and JL carried out under controlled environment conditions, with sampling at 1, 3, 10, and 25 days post inoculation in infected and control plants.ResultsAll of the inoculated trees rapidly developed lesions but no statistically significant differences were found in lesion lengths between EL and JL. RNA-Sequencing comparing control and inoculate saplings identified key differences in differentially expressed genes (DEGs) between the two larch species. European larch had rapid induction of defence genes within 24 hours of infection followed by sustained expression until 25 days after inoculation. Results in JL were more varied; upregulation was stronger but more transient and represented fewer defence pathways. Gene enrichment analyses highlighted differences in jasmonate signalling and regulation including NPR1 upregulation in EL only, and specific aspects of secondary metabolism. Some DEGs were represented by multiple responsive copies including lipoxygenase, chalcone synthase and nucleotide-binding, leucine-rich-repeat genes.ConclusionThe variations between EL and JL in responsive DEGs of interest as potentially related to differences seen in the field and should be considered in the selection of trees for planting and future breeding.

Comprehensive collection of genes and comparative analysis of full-length transcriptome sequences from Japanese larch (Larix kaempferi) and Kuril larch (Larix gmelinii var. japonica)

BackgroundJapanese larch (Larix kaempferi) is an economically important deciduous conifer species that grows in cool-temperate forests and is endemic to Japan. Kuril larch (L. gmelinii var. japonica) is a variety of Dahurian larch that is naturally distributed in the Kuril Islands and Sakhalin. The hybrid larch (L. gmelinii var. japonica × L. kaempferi) exhibits heterosis, which manifests as rapid juvenile growth and high resistance to vole grazing. Since these superior characteristics have been valued by forestry managers, the hybrid larch is one of the most important plantation species in Hokkaido. To accelerate molecular breeding in these species, we collected and compared full-length cDNA isoforms (Iso-Seq) and RNA-Seq short-read, and merged them to construct candidate gene as reference for both Larix species. To validate the results, candidate protein-coding genes (ORFs) related to some flowering signal-related genes ​were screened from the reference sequences, and the phylogenetic relationship with closely related species was elucidated.ResultsUsing the isoform sequencing of PacBio RS ll and the de novo assembly of RNA-Seq short-read sequences, we identified 50,690 and 38,684 ORFs in Japanese larch and Kuril larch, respectively. BUSCO completeness values were 90.5% and 92.1% in the Japanese and Kuril larches, respectively. After comparing the collected ORFs from the two larch species, a total of 19,813 clusters, comprising 22,571 Japanese larch ORFs and 22,667 Kuril larch ORFs, were contained in the intersection of the Venn diagram. In addition, we screened several ORFs related to flowering signals (SUPPRESSER OF OVEREXPRESSION OF CO1: SOC1, LEAFY: LFY, FLOWERING Locus T: FT, CONSTANCE: CO) from both reference sequences, and very similar found in other species.ConclusionsThe collected ORFs will be useful as reference sequences for molecular breeding of Japanese and Kuril larches, and also for clarifying the evolution of the conifer genome and investigating functional genomics.

Forest‐permafrost feedbacks and glacial refugia help explain the unequal distribution of larch across continents

AbstractAimThe continental‐scale distribution of plant functional types, such as evergreen and summergreen needle‐leaf forest, is assumed to be determined by contemporary climate. However, the distribution of summergreen needle‐leaf forest of larch (Larix Mill.) differs markedly between the continents, despite relatively similar climatic conditions. The reasons for these differences are little understood. Our aim is to identify potential triggers and drivers of the current distribution patterns by comparing species' bioclimatic niches, glacial refugia and postglacial recolonization patterns.LocationNorthern hemisphere.TaxonSpecies of the genus Larix (Mill.).MethodsWe compare species distribution and dominance using species ranges and sites of dominance, as well as their occurrence on modelled permafrost extent, and active layer thickness (ALT). We compare the bioclimatic niches and calculate the niche overlap between species, using the same data in addition to modern climate data. We synthesize pollen, macrofossil and ancient DNA palaeo‐evidence of past Larix occurrences of the last 60,000 years and track differences in distribution patterns through time.ResultsBioclimatic niches show large overlaps between Asian larch species and American Larix laricina. The distribution across various degrees of permafrost extent is distinctly different for Asian L. gmelinii and L. cajanderi compared to the other species, whereas the distribution on different depths of ALT is more similar among Asian and American species. Northern glacial refugia for Larix are only present in eastern Asia and Alaska.Main ConclusionThe dominance of summergreen larches in Asia, where evergreen conifers dominate most of the rest of the boreal forests, is dependent on the interaction of several factors which allows Asian L. gmelinii and L. cajanderi to dominate where these factors coincide. These factors include the early postglacial spread out of northern glacial refugia in the absence of competitors as well as a positive feedback mechanism between frozen ground and forest.

Larix species range dynamics in Siberia since the Last Glacial captured from sedimentary ancient DNA

Climate change is expected to cause major shifts in boreal forests which are in vast areas of Siberia dominated by two species of the deciduous needle tree larch (Larix). The species differ markedly in their ecosystem functions, thus shifts in their respective ranges are of global relevance. However, drivers of species distribution are not well understood, in part because paleoecological data at species level are lacking. This study tracks Larix species distribution in time and space using target enrichment on sedimentary ancient DNA extracts from eight lakes across Siberia. We discovered that Larix sibirica, presently dominating in western Siberia, likely migrated to its northern distribution area only in the Holocene at around 10,000 years before present (ka BP), and had a much wider eastern distribution around 33 ka BP. Samples dated to the Last Glacial Maximum (around 21 ka BP), consistently show genotypes of L. gmelinii. Our results suggest climate as a strong determinant of species distribution in Larix and provide temporal and spatial data for species projection in a changing climate.

Современное состояние лиственницы ольгинской (Larix olgensis A. Henry) на Борисовском плато (Приморский край)

The modern literature on dendrology recognizes and describes 3 species of larch: Gmelin (Daurian) larch (L. gmelinii (Rupr) Rupr), Kayander larch (L. cajanderi Mayr.) and Olginsky larch (Larix olgensis A. Henry). However, Far Eastern foresters-researchers believe that the Lyubarsky larch, described in 1931 by V.N. Sukachev, grows on the territory of Primorsky Krai. The article presents research data on the current state of the Olginskaya larch (Lyubarsky larch) biogroups on the territory of the Borisov Plateau in Primorsky Krai. The Olginsky larch vegetation area and the grass cover of the territory is described in detail. The characteristics of the stand are given according to taxation indicators: origin, composition divided into stories (by weight and number of trees), age, forest density, average height and diameter, bonus, sum of cross-sectional areas, stock. The measurement results of 100 larch trees (diameter and height) were processed in the Exel STATISTIKA program. The age of the stand was determined, the influence of the average annual temperature and the annual amount of precipitation on the growth of larch in diameter was analyzed. The dynamics of the growth of model trees in diameter is analyzed. It has been established that the Olginskaya larch under the conditions of the Borisov Plateau shows negative growth rates in diameter with a lack and excess of moisture, and also at high temperatures the growth rates decrease. The analysis showed that in the conditions of the Borisov plateau there is a general dependence of the increments in diameter on climatic factors. Larch trees growing in the same micro-conditions showed completely different growth rates, which is obviously explained by genetic differences.

Исследование морфологических признаков и посевных качеств семян видов рода Larix Mill. в условиях интродукции

The paper presents the results of studying morphological characteristics and sowing qualities of seeds of larch species introduced to the center of European Russia (Larix sibirica Ledeb., L. sukaczewii Dyl., L. decidua Mill., L. marschlinsii Coaz, L. olgensis A. Henry, L. principis-rupprechtii Mayr, L. kaempferi (Lamb.) Carriere, L. laricina (Du Roi) K. Koch). The research was carried out in Moscow (Main Botanical Garden of the Russian Academy of Sciences) and the Moscow region (Ivanteevsky Dendrological Garden, Yegoryevsky phosphorite deposit). This topic is urgent since determination of seed germination and viability is essential for introduction, whereas there are no recommendations for American larch and Prince Rupprecht’s larch in the State Standards (GOST) for determination of sowing qualities and quality class of seeds. The data on the variability of morphological characteristics of seeds of different larch species presented in the paper allow revealing their biological features under introduction conditions, which can be the basis for expanding the use of the studied plants in the center of European Russia. The individual variability of seed length and width, the relationship of these characteristics, as well as germination energy, germination, viability, and seed quality class were considered. Olga Bay larch has substandard seeds. Seeds of other larch species (Siberian, Sukachev’s, European, Margilind, Prince Rupprecht’s, Japanese and American larches) belong to the 2nd and 3rd quality classes. It allows recommending these species for sowing. Siberian larch growing on the Yegoryevsky phosphorite deposit showed a decrease in the sowing qualities of seeds (compared to the species from the Main Botanical Garden of the Russian Academy of Sciences) and the absence of relationship of seed length and width (compared to other objects of the research). Correlation analysis showed differences in linear and curvilinear relationships of seed length and width in Siberian and Sukachev’s larches, as well as in Margilind larch and its parental species (European and Japanese larches).

Novel coupled permafrost–forest model (LAVESI–CryoGrid v1.0) revealing the interplay between permafrost, vegetation, and climate across eastern Siberia

Abstract. Boreal forests of Siberia play a relevant role in the global carbon cycle. However, global warming threatens the existence of summergreen larch-dominated ecosystems, likely enabling a transition to evergreen tree taxa with deeper active layers. Complex permafrost–vegetation interactions make it uncertain whether these ecosystems could develop into a carbon source rather than continuing atmospheric carbon sequestration under global warming. Consequently, shedding light on the role of current and future active layer dynamics and the feedbacks with the apparent tree species is crucial to predict boreal forest transition dynamics and thus for aboveground forest biomass and carbon stock developments. Hence, we established a coupled model version amalgamating a one-dimensional permafrost multilayer forest land-surface model (CryoGrid) with LAVESI, an individual-based and spatially explicit forest model for larch species (Larix Mill.), extended for this study by including other relevant Siberian forest species and explicit terrain. Following parameterization, we ran simulations with the coupled version to the near future to 2030 with a mild climate-warming scenario. We focus on three regions covering a gradient of summergreen forests in the east at Spasskaya Pad, mixed summergreen–evergreen forests close to Nyurba, and the warmest area at Lake Khamra in the southeast of Yakutia, Russia. Coupled simulations were run with the newly implemented boreal forest species and compared to runs allowing only one species at a time, as well as to simulations using just LAVESI. Results reveal that the coupled version corrects for overestimation of active layer thickness (ALT) and soil moisture, and large differences in established forests are simulated. We conclude that the coupled version can simulate the complex environment of eastern Siberia by reproducing vegetation patterns, making it an excellent tool to disentangle processes driving boreal forest dynamics.