Larch Forest Research Articles

Fire‐Induced Carbon Loss and Tree Mortality in Siberian Larch Forests

AbstractClimate change is intensifying the fire regime across Siberia, with the potential to alter carbon combustion and post‐fire carbon re‐accumulation trajectories. Few field‐based estimates of fire severity (e.g., carbon combustion and tree mortality) exist in Siberian larch forests (Larix spp.), which limits our ability to project how an intensified fire regime will affect regional and global climate feedbacks. Here, we present field‐based estimates of fire‐induced tree mortality and carbon loss in eastern Siberian larch forests. Our results suggest that fires in this region result in high tree mortality (means of 83% and 76% at Arctic and subarctic sites, respectively). In both absolute and relative terms, aboveground carbon loss following fire is higher in Siberian larch forests than in North America, but belowground carbon loss is considerably lower. This suggests fundamental differences in wildfire behavior and carbon dynamics between dominant vegetation types across the boreal biome.

On the question of the distribution of Coniferous Island in the north of the Central Kamchatka Depression in the Holocene

Despite the long history of studying the conifers dispersal in the Central Kamchatka Depression during the Holocene, the understanding of vegetation dynamics in the northern part of the depression is much weaker due to the lack of palynological sections. Pollen analysis of a peat section located to the southwestern of Shiveluch volcano allowed an assessment of the "Coniferous Island’s" expansion dynamics in the northern part of the Central Kamchatka Depression. According to the data obtained, the expansion of larch forests in this area began about 700 cal. yrs. BP, i.e. 100-150 yrs. later than in the southern part of the depression. Spruce, which replaces larch during succession, began to spread here about 400 cal. yrs. BP, as in the rest of the depression.

Environmental Changes in the Eastern Arctic during Marine Isotope Stages 80 and 81

Palynological analysis of a 317-m-long sediment core obtained from Lake El'gygytgyn (67° 30' N, 172° 05' E) located in the Eastern Arctic documents the changes in vegetation between 2.103 and 2.146 Ma. This interval encompasses marine isotope stages (MIS) 80 and 81 and includes the Reunion paleomagnetic event, an important chronological event within MIS 81. Seven pollen zones depict the varying plant communities associated with interglacial, interstadial, and glacial intervals. The warmest climatic conditions occurred during MIS 81 (pollen zone E2) when coniferous forests dominated the landscape. These forests also included moderately thermophilous broadleaf trees and shrubs. The interstade (MIS 81, pollen zone E3) is characterized by open larch forests and forest-tundra. During the period of deepest climatic cooling, which occurred at the end of MIS 80 (pollen zone E7), larch forest-tundra and shrub tundra were present across the region. The palynological analysis of sediments from Lake El'gygytgyn illustrates the varying responses of vegetation to a wide range of climatic conditions and suggests that modern Arctic communities may disappear in the future as a result of global warming.

Effects of environmental conditions on seed yield of larch forest in green zone of Ulaanbaatar

The flowering of trees and shrubs serves as the primary indicator of the seed yield for the year. The duration of flowering, however, varies with the weather conditions throughout the year. This study aimed to determine the indicators of flowering and seed yield of larch forests in the green zone of Ulaanbaatar city and understand the effects of climate change on it. The study was carried out in the mixed forest of Khandgait and Jigjid valleys. We used sample plot separation, tree taxation, and tree selection methods to define basic parameters, and collected and analyzed soil samples. Differences between the flowering of trees and the chemical parameters of the soil were determined using one-way ANOVA. As a result, the study area consisted of a taiga mixed forest with mature trees including larch, spruce, and cedar aged between IV-VII and with a thickness of 0.6-0.7. The average diameter and height of the trees were 22.5–30.2 cm and 18.6–18.8 m, respectively, and according to the selection category, normal trees were prevalent. The trees began to bloom evenly in the second ten days of May, but due to sudden coldness in spring and continuous cold rain, the larch flowers dried up and did not produce seeds. According to the soil analysis, the content of humus contained in 100 g of soil was sufficient. The average pH was 5.8, and conductivity was ranged between 0.04 and 0.4. Carbonate content was not detected in all layers of the soil. The uppermost surface layers consisted of sandy soil followed by light loam and loam in the following layers. In conclusion, due to the climate condition, the larch trees in the green zone of Ulaanbaatar city have achieved only a 3-point flowering. Улаанбаатар хотын ногоон бүсийн шинэсэн ойн үрийн ургацад ургах орчны үзүүлэх нөлөө ХУРААНГУЙ: Мод, сөөгний цэцэглэлт нь тухайн жилийн үрийн ургацыг тодорхойлох гол үзүүлэлт болдог. Цэцэглэлтийн үргэлжлэх хугацаа нь тухайн жилийн цаг агаарын байдлаас шалтгаалж харилцан адилгүй байдаг. Энэхүү судалгааны зорилго нь Улаанбаатар хотын ногоон бүсийн шинэсэн ойн цэцэглэлт, үрийн ургацын үзүүлэлтүүдийг тодорхойлж, тухайн бүс нутгийн нөхцөлд уур амьсгалын өөрчлөлтийн үзүүлэх нөлөөг судлахад оршино. Судалгааг Хандгайтын ам, Жигжидийн амны шинэс зонхилсон холимог ойд гүйцэтгэв. Дээж талбайг тусгаарлан моддын таксацийн үндсэн үзүүлэлт, моддын селекцийн үнэлгээ болон цэцэглэлтийн үнэлгээ, дээж талбайн хөрсний шинж чанарын үзүүлэлтийг арга зүйн дагуу тодорхойлов. Моддын цэцэглэлт болон дээж талбайн хөрсний химийн шинж чанарын үзүүлэлтийн ялгааг нэг хүчин зүйлт вариансын анализаар (One-way ANOVA) тодорхойлов. Судалгааны дүнгээс үзэхэд, дээж талбай дахь модод насны IV-VII ангид хамрагдах болц гүйцсэн 0.6-0.7 өтгөрөлтэй шинэс, гацуур, хуш бүхий тайгын холимог ой тархан ургаж байна. Ойн дундаж диаметр 22.5-30.2 см, дундаж өндөр 18.6-18.8 м, селекцийн ангиллаар хэвийн модод зонхилон тархаж байна. Цэцэглэлтийн явцаас үзэхэд, 5-р сарын II арав хоногт модод жигдрэн цэцэглэж эхэлсэн боловч хаврын гэнэтийн хүйтрэлт, үргэлжилсэн хүйтэн бороо зэрэг шалтгааны улмаас шинэсний цэцгүүд хатаж цаашид үр боловсрох боломжгүй болсон байна. Хөрсний шинжилгээний дүнгээс үзэхэд, 100 г хөрсөнд агуулагдах ялзмагийн агууламж хангалттай, хөрсний уусмалын орчин дунджаар pH 5.8, хөрсний бүх үе давхаргад карбонатын агууламж илрээгүй, цахилгаан дамжуулах чанар багаас дунд зэрэг, хөдөлгөөнт фосфор, калийн хангамжаар сайн, механик бүрэлдэхүүний хувьд хамгийн дээд өнгөн үе давхаргууд элсэнцэр, түүнээс доош хөнгөн шавранцар болон шавранцар ширхгийн бүрэлдэхүүнтэй байгаа нь модлог ургамал ургахад тохиромжтой байв. Улаанбаатар хотын ногоон бүсийн шинэсэн ойд 5-р сарын II арав хоногт тохиолдох цочир хүйтрэлтийн улмаас моддын цэцэглэлт 3 балл буюу дундаж үнэлгээтэй байв. Түлхүүр үгс: Боргоцой, Ногоон бүсийн ой,Үрийн ургац, Үрийн мод, Уур амьсгал, Цэцэглэлт

Evaluating Forest Site Quality Using the Biomass Potential Productivity Approach

Biomass productivity is of great significance for the evaluation of forest quality, which is important for the improvement of forest management. We propose the computational methods of biomass potential productivity (BPP) and biomass realistic productivity (BRP), both of which provide reliable practical guides for predicting forest growth under multi-aged, multi-species, and multi-layered canopy conditions. We used 2222 national forest inventory plots that were measured in four consecutive periods in the Jilin Province for this purpose. We analyzed and verified the computational methods of BPP based on the BRP and evaluated its practical significance. The results showed that growth models of the stand height, stand basal area, and stand biomass of four forest types (pure larch forest, larch broadleaf mixed forest, Mongolian oak pure forest, and Mongolian oak broadleaf mixed forest) fit adequately, BPP was greater than BRP, and this difference decreased with an increasing stand age, suggesting that the potential productivity of the middle-aged and young forest was higher than that of the mature forest, although the difference is minimal. In addition, the realistic productivity of stands with better site quality was close to the potential productivity, which is consistent with the biological significance of the potential productivity of the biomass. The degree of difference between the potential productivity of the biomass and the realistic productivity of biomass also decreases with the decline in site quality, and it can be termed as the potentially improved stand biomass. The BPP model was able to perform well in both the pure and mixed forests. The BRP not only verifies the rationality of the BPP but can be also used to quantify the forest site quality, which is helpful for evaluating forest growth and informed decision making in forestry.

Responsive characteristics of soil water regimes to rainfall events in a boreal larch forest in China: Dynamic processes and decoupling effects

Investigating the soil water dynamics in relation to rainfall events is of great importance for enhancing our understanding of eco-hydrological processes and improving soil hydrological models. However, the lack of long-term, in-situ observational data and the neglect of soil moisture decoupling have hindered the study of dynamic responses in soil water regimes to rainfall events in China’s boreal forests with permafrost. This study utilized soil water content monitoring and rainfall observational data from the Xing’an larch (Larix gmenilii) forest in Northeast China during the growing seasons of 2015–2021 to evaluate the dynamic response of soil water regimes to rainfall events. The results show a significant increase in the decoupling strength between soil water and rainfall with increasing soil depth. The thresholds of rainfall amount (RA), duration (RD), and intensity (RI) for triggering soil wetting events also increased. Soil water dynamic processes exhibited inconsistent and complex patterns in response to the hierarchical effects of RA, RD, and RI along the vertical soil profile. However, the dominant controls on soil water dynamic responses to RA, RD, and RI varied depending on specific response metrics, such as the accumulated soil water content increments (ASMI), duration time (DT), and the mean slope of the soil wetting curve (Sm). Interestingly, the dominant factor for affecting response time (RT) changed from RI to RD as soil depths increased. Importantly, the decoupling of soil moisture led to a substantial reduction in the responsiveness of these metrics of subsurface soil water to rainfall, and the role of the decoupling effect diminished with increasing soil depths. These findings highlight the complexity of the dynamic response of soil water to rainfall events and provide new insights into the relationship between soil water dynamics and rainfall features through the introduction of the decoupling of soil moisture in boreal forests.

Resource characteristics of Rhododendron adamsii Rehder in the Okinsky district of the Republic of Buryatia (East Sayan)

This paper presents resource and phytocoenotic characteristics of Rhododendron adamsii populations in the Oka district of the Republic of Buryatia. The aim of the study was to establish the status of Rhododendron adamsii populations in the Orlik river valley as a place of active collection of plant raw materials. During fieldwork 74 survey plots were established and 27 geobotanical releves of phytocenoses with object of study were performed. At each site we carried out calculation and measurement work. As a result of the study, material on the number, yield and morphology of Rhododendron adamsii populations in the Oka district was collected. As a result of the study it was found that the most productive are populations in lichen-rodendron larch forest, where the yield was 195 g.

About two important paradigms of modern geobotany: supracenotic organization and phylocenogenesis

In the 20th century, many brilliant personalities enriched not only domestic, but also world science, including V N. Sukachev, E. M. Lavrenko, V B. Sochava. In general, paradigms are important in the development of science as examples of problem posing models or new approaches to the implementation of ideas. The paradigm of the spatial organization of phytosystems from the standpoint of a universal scientific approach is affirmed in the triad of the process of cognition: see - describe - explain. It reflects the concept of the spatial-structural approach in geobotany. To the question - why, the meaning of the explanatory paradigm of the process of cognition is focused. As an example, the results of our studies of the vegetation of the upland terraces of the Altai Mountains. Based on the analysis of their most important features of the structure and modes of operation, a schematic diagram of the types of interaction of elements of the terraced slope was created, which made it possible to reach a forecast in the dynamics of their development. The paradigm of adaptive morphogenesis of plants in ecosystems, landscape and topolithogenic spheres is expressed in the triad of relationships: the center of ore genesis - geochemical anomaly - adaptive morphogenesis. This is the basis of the biogeochemical conditionality of florogenesis, which means the prospects for research into the latest foci of speciation -the formation of endemic species and communities of vegetation. Thus, we established selective accumulation of gold (Au) by fruticose lichens in the communities of taiga larch forests of the Ilchir tract in the foothills of the Kitoi bald mountains (Eastern Sayan). The selective accumulation of elements in phytocenoses indicates the biogeochemical conditionality of florogenesis. An endemic cryophyte-steppe association with Festuca komarovii Krivot. is described. Phylocenogenesis as a process of adaptive morphogenesis of biosystems is the growth point of geobotany, and its result - speciation and cenogenesis are realized in complex geobotanical studies.

Species Diversity in Larch Forests of Amur Oblast and the Republic of Sakha (Yakutia)

Species Diversity in Larch Forests of Amur Oblast and the Republic of Sakha (Yakutia)

Biological Productivity of the Post-Fire Larch Forests in the Mountain Regions of Krasnoyarsk Krai

Biological Productivity of the Post-Fire Larch Forests in the Mountain Regions of Krasnoyarsk Krai

Life forms affect beta-diversity patterns of larch forests in China

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch (Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components (species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total beta-diversity and its components in different life forms (i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total beta-diversity of larch forests was mainly dependent on the species turnover component. In all life forms, total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%–25% of total beta-diversity, 18%–27% of species turnover component, and 4%–16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

Soil microbial diversity under different types of interference in birch secondary forest in the Greater Khingan Mountains in China.

Soil microorganisms are an important component of soil ecosystems with an indispensable role in forest ecosystems. We analyzed the soil microbial diversity in birch secondary forest formed by natural restoration or artificial reconstruction after interference by burning, clear cutting, and gradient cutting, and the Betula platyphylla Suk undisturbed forest in the Greater Khingan Mountains in China. Illumina high-throughput sequencing technology was used to analyze the characteristics of the soil microbial community during the restoration process of birch secondary forest caused by the different types of interference. The relationships between bacteria and fungi were analyzed. The gene functions of the soil bacterial community and the ecological functions of soil fungi were predicted using PICRUSt and FunGuild, respectively. At the phylum level, the species and quantity of bacteria were more abundant than that of fungi. At the genus level, no obvious differences in the abundance of bacteria were observed; there were obvious differences in the abundance of fungi. Among the eight sample plots, the artificial larch forest belt had the highest bacterial and fungal alpha diversity, which was slightly higher than undisturbed forest, while the other sample plots were significantly lower. Gradual cutting pure birch forest bacteria and fungi had the highest beta diversity, and artificial larch forest belt bacteria and heavy burn sample plot fungi had the lowest beta diversity. Samples from the cutting and burning sample plots were significantly different from the undisturbed forest at the phylum level of Acidobacteriae, Acidimicrobiia, Mortierellomycetes and Sordariomycetes. We found statistical differences in biomarkers between bacterial and fungal communities in undisturbed forest and artificial larch forest belt and burn sample plots. PICRUSt prediction and FunGuild prediction showed that soil bacterial and fungal communities were rich in gene and ecological functions, respectively. In the microbial network, the stability or anti-interference performance of the fungal community was higher than that of bacteria. Our data reveal the characteristics of the soil microbial community during the restoration process of Betula platyphylla Suk secondary forest under different types of disturbance, which is of great significance for understanding the role of soil microorganisms in the forest ecological cycle.

Global tree growth resilience to cold extremes following the Tambora volcanic eruption

Although the global climate is warming, external forcing driven by explosive volcanic eruptions may still cause abrupt cooling. The 1809 and 1815 Tambora eruptions caused lasting cold extremes worldwide, providing a unique lens that allows us to investigate the magnitude of global forest resilience to and recovery from volcanic cooling. Here, we show that growth resilience inferred from tree-ring data was severely impacted by cooling in high latitudes and elevations: the average tree growth decreased substantially (up to 31.8%), especially in larch forests, and regional-scale probabilities of severe growth reduction (below −2σ) increased up to 1390%. The influence of the eruptions extended longer (beyond the year 1824) in mid- than in high-latitudes, presumably due to the combined impacts of cold and drought stress. As Tambora-size eruptions statistically occur every 200–400 years, assessing their influences on ecosystems can help humankind mitigate adverse impacts on natural resources through improved management, especially in high latitude and elevation regions.

Evolution of vegetation of the Lake Khanka Depression in the southernmost of the Russian Far East in the Holocene

This paper presents recently obtained palynological results regarding to the evolution of vegetation of the Khanka Depression in the Holocene. Radiocarbon-dated pollen records evidence that the evolution of vegetation in this area was more complicated than one has previously thought. As a result of a rapid increase in heat supply in the Early Holocene, the plants of the Manchurian flora, primarily Ulmus davidiana, Ulmus laciniata, Quercus mongolica, and Pinus koraiensis, began to expand to the Khanka Depression. However, Sphagnum mires with Betula grandulosa, Betula pubescens, and sparse forests of Larix, still remained in plains and valleys. Picea jezoensis, Pinus pumila, Betula grandulosa, Betula alnobetula, Betula pubescens, Pinus pumila and Larix were widespread in the mountains. During the Middle Holocene these cold-tolerant plants of the north-boreal flora, completely disappeared. Broad-leaved and fir-pine forests have become widespread. The vegetation of the Khanka Depression compared with modern one was characterized by great diversity of broad-leaved plants. At the beginning of the Late Holocene cooling has caused the expansion of Betula grandulosa, Betula alnobetula, Abies nephrolepis, Picea jezoensis, Betula pubescens, Betula costata, and Alnus hirsuta. The areas of forb meadows expanded on the plains. Larch sparse forests, thickets with domination of Betula grandulosa and Sphagnum mires reappeared. However, some thermophilic plants, such as Pinus koraiensis, Abies nephrolepis, Quercus mongolica, Juglans mandshurica, Ulmus davidiana, and Ulmus laciniata have survived. Since 1 300 cal BP, vegetation of the Khanka Depression began to degrade due to fires, plowing of the land, and deforestation.

Regeneration and changes in plant community of the subtaiga forbs-fescue larch forest destroyed by harmful insects

In Mongolia, in recent years, the number of harmful insects has increased, causing the same damage as fires. This article presents the results of a long-term observation of regeneration and plant community change in the forest which in 2001 was destroyed by a Siberian moth in Gachuurt valley of the green zone of the city of Ulaanbaatar. Within 21 years after the destruction of the forest by harmful insects, natural regeneration of the forest does not occur, and the forbs-fescue meadow community is formed due to the process of terrain degradation. Larch forests destroyed by insects can only be restored by planting larch seedlings. Хөнөөлт шавжид нэрвэгдсэн алаг өвс-улалжит тайгархаг шинэсэн шинэсэн ойн ургамал бүлгэмдлийн өөрчлөгдөл, сэргэн ургалт Хураангуй. Монгол оронд сүүлийн жилүүдэд хөнөөлт шавжийн тоо толгой олширч түймрээс дутахгүй хөнөөл учруулж байна. Гачуурт орчмын ногоон бүсийн ойд 2001 онд гарсан Сибирийн хүр эрвээхэйн хүрэнцэрт идэгдэж үхсэн алаг өвс-улалжит шинэсэн ойн сэргэн ургалт, ургамал бүлгэмдлийн өөрчлөгдлийн олон жилийн мониторингийн үр дүнг энэхүү өгүүлэлд оруулав. Хөнөөлт шавжид нэрвэгдэж хатсанаас хойш 21 жилийн хугацаанд ойн байгалийн сэргэн ургалт огт ажиглагдаагүй ба хээржих үйл явц явагдаж алаг өвс-улалжит нугын хээрийн бүлгэмдэл үүссэн байна. Хөнөөлт шавжид нэрвэгдэж үхсэн шинэсэн ойг шинэсний тарьцаар ойжуулалт хийх замаар нөхөн сэргээх боломжтой. Түлхүүр үгс: Сибирь шинэс (Larix sibirica), Хөнөөлт шавж, Ургамал бүлгэмдлийн өөрчлөгдөл, Ойн сэргэн ургалт

Природные закономерности почвенно-растительного покрова юго-западных отрогов Баджальского хребта

Expert assessment has been performed using the cartographic method in a key area of the Badjal Rige southwestern spurs. The basic natural regularities of the soil and vegetation cover have been identified, including heterogeneity and contrasting change of soil and vegetation complexes within the limits of vertical zoning; belt-zone differentiation (alpine, subalpine, and taiga); wide distribution of corroms; maximum diversity and high dynamism of floodplain soil and plant complexes. The article presents a 1 : 40,000-scale vegetation map; it is based on the ecological and phytocenotic classification of vegetation. The main mapped units are association groups and their combinations. The legend reflects 13 divisions of the vegetation cover. Corroms occupy the largest areas (24.9 %). The subalpine zone vegetation makes 20.9 % of the total area. Mountain taiga forests take 32.9 % of the total mapped territory, including spruce forests (7.3 %), larch forests (21.9 %), and birch-larch forests (3.7 %). Larch woodlands are responsible for slightly less than 3 % of the territory; sphagnum oligotrophic bogs, for 0.5 %. Floodplain forests are spread over the area of 12.5 %; that includes spruce forests (4.8 %), chosenia-poplar-larch forests (4.5 %), and poplarlarch forests (3.2 %). 4.4 % of the area is pebbled. There are 5 types and 13 subtypes of soils represented in the soil cover. Dystric histosols and leptic folic histosols form the soil background. Soils are characterized by the presence of organogenic-coarse humus or dry peaty horizons. Organic matter content is high or very high. The reaction of the soil solution varies from very acidic to acidic. Based on the vegetation map, soil areas are roughly quantified. In terms of the set of soil and plant complexes as well as their regular change in vertical zoning, the area under discussion is the reference territory. Represented here is the Okhotsk type of land cover zoning, which is typical for the Far East with its monsoonal climate.

Растительные сообщества Восточной Арктики в изотопные стадии 50-59

Palynological analysis of sediments from Lake El'gygytgyn, formed during oxygen-isotope stages 50-59, documents the changes of cold stages, interstades and interglaciations. Ten pollen zones were identified and correspond to the interval 1.4920-1.6975 million years ago. This interval includes the Gilsa magnetic event (1.68 Ma), which is an important chronological landmark. Larix pollen appears in the palynological spectra of all stages. The presence of this taxon during warm climates indicates that larch forests established in the areas of the Anadyr Plateau and Lake El'gygytgyn and replaced the larch forest-tundra, which is characteristic of the cold stages. The warmest climatic conditions occur in pollen zone 6 (MIS55) and are in the range of 1.4920-1.6975 million years ago. Vegetation in the period of maximum cooling is characterized by pollen zones 7-10 (MIS50 - MIS54). The interval 1.4920-1.6975 million years ago represents the last step in the completion of the Quaternary vegetation history from a unique region of Arctic Siberia.

THE STATE AND DYNAMICS OF THE BORDERS OF CEDAR FORESTS AT THE WESTERN TANNU-OLA RANGE IN THE TYVA REPUBLIC

The paper presents the recent response of dark coniferous forest and cedar undergrowth in the forests of the Western Tannu-Ola Range to the observed climate change in the region. According to the nearby Chadan meteorological station, the anomaly of the average annual air temperature was 1,6 ± 0,8°С, the anomaly of the growing season was 1,0 ± 0,7°С. Key study areas are located in the Tyva Republic within 50°55′-51°15′N and 91°30’-92°20’E, which corresponds to three altitudinal levels: the lower belt of the middle mountains (1100-1300 m a.s.l.) bordering the steppe and covered with larch forests with birch; the middle belt of the middle mountains (1300-1800 m a.s.l.) covered with larch and cedar forests; larch and cedar forests of the upper belt of the middle mountains (1800-2120 m a.s.l.). In the course of field work, the increment of the top shoot of cedar sapling (Pinus sibirica Du Tour) was measured, as well as its height, age and total number. Correlations between the increment, air temperature and relative humidity were quantitatively determined using data from the Chadan weather station for a number of years. The results indicate a positive correlation with humidity in the lower zone of the middle mountains and with air temperature in the upper zone of the middle mountains. Higher amounts of cedar sapling in the lower zone of the middle mountains and in the upper zone of the middle mountains confirm the shift of dark coniferous forests down and up the ridge under the regional climate warming. Space images of Landsat TM/ETM+/OLI show the increasing values of NDVI and NDWI vegetation indices. According to satellite images, an increase in the area of dark coniferous forests over the past decades was calculated for the territory of key areas; however, the reliability of these data was not evaluated statistically. The work needs to be continued in the field.

Mycorrhizal parameters of Larix sibirica fine roots across gradients of main environmental factors and altitude

Siberian larch (Larix sibirica) forests cover the largest areas in the Eurasian boreal zone, but the knowledge on its root system and ectomycorrhizas (EMs) are insufficient. The aim of this research is to find out whether the morphological parameters of L. sibirica EMs respond to the changes in altitude and main environmental factors. We measured the EM diameter, root diameter, mantle width and volume share, share of tannin cell layers, EM density and length of L. sibirica fine roots in four main types of habitats across the altitudinal gradient in the Urals. The diversity of fungal mantle types depended on the type of habitat. The minimal diversity of fungal mantles and the prevalence of plectenchymatous mantles were found in moister and unfertile habitats of sphagnous type. In other types of habitats, the diversity of fungal mantle types was approximately twice higher. A combination of factors (habitat type and altitude) significantly determined all quantitative parameters of the Larix EMs under study. We found a reduction in the EM linear dimensions with increasing altitude and a deterioration of environmental conditions, accompanied by a decrease in their functional parameters with a slight increase in the EM density and the share of nonmycorrhizal roots.

Comparative analysis of microbial community structure in different times of Panax ginseng Rhizosphere microbiome and soil properties under larch forest

BackgroundPanax ginseng cultivated under the forest is popular because its shape and effective ingredients are similar to wild ginseng. The growth of P. ginseng in the larch forest is generally better than in the broad-leaved forest, and the incidence rate of diseases is low. Therefore, the selection of forest species is one of the basic factors in the successful cropping of P. ginseng.MethodsIllumina HiSeq high-throughput sequencing was used to analyze the 16S rRNA/ITS gene sequence of P. ginseng rhizosphere soil under larch forest to study the rhizosphere microbiome's diversity and community composition structure.ResultsThe species classification and richness of rhizosphere bacterial and fungal communities in the same-aged P. ginseng were similar. Consistent with the soil system of commonly cultivated crops, Proteobacteria, Actinobacteriota, Acidobacteriota, Verrucomicrobiota, Chloroflexi, and Basidiomycota, Ascomycota were the dominant phylum of bacteria and fungi, respectively. Compared with the soil without planting P. ginseng, the diversity of microorganisms and community structure of continuous planting for 2 years, 5 years, and 18 years of P. ginseng rhizosphere soil had little change. The accumulation levels of Ilyonectria, Fusarium, Gibberella, and Cylindrocarpon were not significantly increased with planting P. ginseng and the increased age of cropping P. ginseng.ConclusionsThe results of this study showed that the soil function of the larch forest was good, which provided a theoretical basis for the land selection and soil improvement of cultivating P. ginseng under the larch forest.