Coniferous Broad-leaved Forest Research Articles

Effects of vegetation type, season, and soil properties on soil microbial community in subtropical forests

The diversity and composition of soil microbial community in forests are affected by vegetation type, season, and soil properties, but the relative importance of these factors on the diversity and composition of microbial community is poorly understood. In this study, high-throughput sequencing was used to assess the soil prokaryote (16S rRNA) and fungal (ITS rRNA) communities of five vegetation types (evergreen broad-leaved forest [EBL], deciduous broad-leaved forest, mixed coniferous–broad-leaved forest, coniferous forest [CF], and secondary shrubland [SS]) for four seasons in a secondary subtropical forest in Eastern China. Soil physicochemical properties and plant diversity were also surveyed for each vegetation type. Vegetation type, season, and their interaction significantly affected the Shannon diversity indexes of soil prokaryotes. The Shannon index of soil fungi was affected by vegetation type. The soil prokaryote and fungal compositions of the five vegetation types were significantly different. The prokaryote compositions of EBL, CF, and SS significantly changed in four seasons, but only the fungal composition of SS changed with the seasons. Variation partition showed that vegetation type and season individually explain 25% and 29% of the variance in prokaryote composition and 19% and 1% of the variance in fungal composition, respectively. Prokaryote diversity and composition were significantly driven by soil pH and organic carbon and fungal diversity and composition were significantly driven by soil pH and electrical conductivity when controlling the effects of vegetation types and seasons.

Renewal of Fraxinus mandshurica Rupr. in Mixed Coniferous-broad Leaved Forests of the Southern Far East

Renewal of Fraxinus mandshurica Rupr. in Mixed Coniferous-broad Leaved Forests of the Southern Far East

Temporal effects of thinning on the composition and growth of regenerated woody plants in Larix kaempferi plantations

Understanding the temporal effects of thinning on the composition and growth of regene-rated broadleaved woody species in coniferous plantations can provide profound references for promoting the conversion of monoculture plantations into mixed conifer-broadleaved forests, which could solve the problem that the production and ecological functions of monoculture plantations cannot be balanced. We compared the composition of regenerated woody plant species in Larix kaempferi plantation with short-term (1-3 years), medium-term (4-9 years) and long-term (>9 years) after thinning. Furthermore, we selected three regenerated tree species with higher importance value and reciprocal symbiosis with L. kaempferi, which differed in shade tolerance, including shade-intolerant species Quercus mongolica, intermediate shade-tolerant species Acer mono, and shade-tolerant species Tilia mandschurica. We analyzed the relationships between light conditions (i.e., canopy density) and the growth (i.e., base diameter and height) of those species in L. kaempferi plantation with different terms after thinning. The results showed that 46 species of regene-rated broadleaved woody plants were recorded in thinned plantations. The common and dominant tree in different terms after thinning was A. mono, and the shrub species were Lonicera japonica and Euonymus alatus. With the increasing time after thinning, species richness of regenerated trees decreased, but the ratio of tree to shrub species increased and the intermediate shade-tolerant tree species took the dominant position. The temporal effect of thinning on the growth of three tree species was affected by shade tolerance ability. Basal diameter and height of T. mandschurica were higher than those of Q. mongolica and A. mono. With the increases of time after thinning, basal diameter of T. mandschurica and height of A. mono were more sensitive to light, indicating that there were respectively "a shade tolerance strategy" and "a shade avoidance strategy" to adapt to the post-thinning environment. The effects of thinning on the composition and growth of regenerated broadleaved woody species in L. kaempferi plantations were significantly time-sensitive. When deve-loping thinning measures to promote the regeneration of broadleaved trees in plantations, we should consider to extend the thinning interval appropriately to ensure the growth of broadleaved tree seedlings (e.g., T. mandschurica and A. mono) and accelerate their migration into the canopy layer. This would promote the formation of mixed conifer-broadleaved forests and eventually realize the sustainable development of plantations.

Biodiversity of Algae and Cyanobacteria in Biological Soil Crusts Collected Along a Climatic Gradient in Chile Using an Integrative Approach.

Biocrusts are associations of various prokaryotic and eukaryotic microorganisms in the top millimeters of soil, which can be found in every climate zone on Earth. They stabilize soils and introduce carbon and nitrogen into this compartment. The worldwide occurrence of biocrusts was proven by numerous studies in Europe, Africa, Asia and North America, leaving South America understudied. Using an integrative approach, which combines morphological and molecular characters (small subunit rRNA and ITS region), we examined the diversity of key biocrust photosynthetic organisms at four sites along the latitudinal climate gradient in Chile. The most northern study site was located in the Atacama Desert (arid climate), followed by open shrubland (semiarid climate), a dry forest region (Mediterranean climate) and a mixed broad leaved-coniferous forest (temperate climate) in the south. The lowest species richness was recorded in the desert (18 species), whereas the highest species richness was observed in the Mediterranean zone (40 species). Desert biocrusts were composed exclusively of single-celled Chlorophyta algae, followed by cyanobacteria. Chlorophyta, Streptophyta and cyanobacteria dominated semiarid biocrusts, whereas Mediterranean and temperate Chilean biocrusts were composed mostly of Chlorophyta, Streptophyta and Ochrophyta. Our investigation of Chilean biocrust suggests high biodiversity of South American biocrust phototrophs.

Ecological-coenotic characteristics of <i>Cantharellus cibarius</i> Fr. and its tolerance to human impact in southern taiga and sub-taiga forests of the Kirov Region

The paper analyzes plant communities with Cantharellus cibarius Fr. in southern taiga and sub-taiga forests in the Kirov Region. Golden chanterelle occurs mostly in pure pine forests and pine forests mixed with spruce and birch of green-moss, lichen and cowberry types in young to maturing stands; the crown density is low or medium. Species richness of herbaceous-shrub storey in the studied communities varied from 5 to 29. The ecological preferences of C. cibarius, defined with Ellenberg (1974) scales, allow to characterize the species in the following way: temperate climate species, shade-resistant, rarely found in conditions of total shading; mesophyte regarding soil humidity, prefers acidic soils with low nitrogen, but, as an exception, marked on neutral soils rich in nitrogen. The differences in the species ecological preferences in conditions of southern taiga and sub-taiga are insignificant. The hemeroby index varied from 0,05 to 0,33 for the studied communities. The average share of species tolerant to human impact was 13,23%, and the share of anthropophobic species 86,77%. These data characterise C. cibarius as the species capable of tolerating moderate human impact in southern taiga subzone, but being less tolerant to human impact in sub-taiga areas and coniferous-broadleaved forests.

Геоинформационная поддержка оценки бюджета углерода лесных экосистем

На примере лесного района хвойно-широколиственных (смешанных) лесов Европейско-Уральской части России показана возможность использования инструментария ГИС для поддержки климатических исследований, связанных с оценкой экологического потенциала лесов по накоплению биогенного углерода. The possibility of using GIS tools to support climate research related to the assessment of the environmental potential of forests to store biogenic carbon is shown by the example of the forest area of coniferous-broadleaved (mixed) forests of the European-Ural region of Russia. GIS tools allowed for identification of carbon budget accounting units of regional and local levels. With the help of ArcGIS software, a map of the division of the Russian territory into forest zones and forest areas with homogeneous site specific conditions in accordance with the regulatory documents of the Ministry of Natural Resources of the Russian Federation has been prepared. Territorial and spatial representation of forest taxation characteristics input parameters of model calculations of carbon deposition and carbon budget within the forest lands of the research object is considered. The maps of ecology and resource potential of the forest areas ecosystems were made by ArcGIS software. The indicators of the annual carbon accumulation by ecosystems (NEP) over the forest management units dedicated to the zone of coniferous-broadleaved (mixed) forests of the European-Ural part of Russia and the carbon budget (NBP) were calculated with data of the State Forest Register (SFR) as of 01.01.2016. The results of model calculations of carbon sequestration by coniferous-broadleaved (mixed) forests of the European-Ural part of Russia and carbon balance in the cartographic form are presented.

Lignicolous fungal assemblages and relationships with environment in broadleaved and mixed forests from the North-East Region of Romania

Background and aims – Lignicolous fungal assemblages perform numerous functions in forest ecosystems, one of the most important being their capacity to decay wood. As a consequence of their belonging to different ecological niches, the forest ecosystem influences the fungal assemblages in terms of species richness and composition. Methods – In this study we analyzed the main lignicolous macrofungal assemblages in some deciduous and mixed deciduous-coniferous forests in the North-East Region of Romania. We searched to find fungal indicator species for a certain forest type and which are the main drivers and their effects on the composition of the lignicolous macrofungal assemblages. Fungal assemblages were identified using a hierarchical agglomerative clustering procedure, while diagnostic species for each cluster were identified based on the indicator value index. Relationships between fungal composition of plots and environmental variables were performed using detrended and canonical correspondence analyses.Key results – A total of 377 fungal taxa in approximately 4600 records (in 59 plots) were identified. Six distinct clusters of lignicolous fungal assemblages were defined and separated three groups: 1) species-rich lignicolous fungal assemblages in beech forests (1 cluster), 2) well defined fungal assemblages in the mixed broadleaved-coniferous forests (2 clusters), and 3) fungal assemblages typical to oak forests (3 clusters). Ordination methods highlighted the forest type as the most important factor influencing the fungal composition of plots. Forestry Aridity Index, tree diversity and large trees basal area were also important factors for fungal assemblages but with a lower contribution. Conclusion – In the studied region, fungal assemblages changed from oak to beech and to mixed, broadleaved-coniferous forests mainly as a consequence of different tree composition. Climate also shaped fungal composition but to a lesser extent.

Variations in pollen deposition of the main taxa forming the land cover along a NW–SE transect in European Russia: results of a ten year Tauber trap monitoring period

Annual pollen accumulation rates of the main tree and shrub taxa of European Russia (Picea, Pinus, Betula, Alnus, Quercus, Tilia, Fraxinus, Ulmus and Corylus), as well as several herbaceous taxa (Poaceae, Cyperaceae, Chenopodiaceae and Artemisia), were obtained using Tauber pollen traps which were placed along a northwest to southeast transect in European Russia. The work was carried out within the framework of the Pollen Monitoring Programme (PMP). The data were analysed using both traditional interpretations of PAR (pollen accumulation rate) values and numerical methods (linear regressions and canonical correspondence analysis, CCA). The various vegetation zones: broadleaved-coniferous forest, broadleaved forest and forest-steppe, differ from each other by the absolute pollen values (PARs) of forest-forming taxa and several wind-pollinated herbs. However, no statistical support for zonal differentiation based on these PARs has been found. The only obvious difference was observed between the forest zone and the forest-steppe. The climatic gradient along the NW–SE transect is reflected by changes in pollen values, but is smoothed due to human influence during past centuries and as a consequence of the dominance of secondary vegetation formations. The highest total PAR, as well as PARs of all the forest-forming taxa, was observed in the southern part of the mixed broadleaved-coniferous forest zone (RU-ZV). The PARs of thermophilic taxa (Tilia, Fraxinus, Acer, Ulmus, Quercus and Corylus), as well as of Picea correspond to warmth availability which is under the influence of a combination of latitude, continentality of climate and microclimatic conditions. According to linear regressions, Picea, Tilia, Quercus and Corylus PARs correspond to Tjul, the July temperature of the previous season. Canonical correspondence analysis indicates that temperature, in particular Tjul, is the main climatic parameter controlling the variation of modern pollen rain.

Soil-surface pollen assemblages and quantitative relationships with vegetation and climate from the Inner Mongolian Plateau and adjacent mountain areas of northern China

We statistically analyzed 396 soil-surface pollen samples from the Inner Mongolian Plateau and its adjacent mountain areas of northern China to gain insights into pollen–vegetation–climate. The results of indicator species analysis, canonical correspondence analysis (CCA) and boosted regression tree (BRT) analysis suggest that: 1) soil-surface pollen assemblages can differentiate between desert, steppe, meadow steppe, cool broadleaved forest, cool conifer forest, and temperate forest, but fail to differentiate between steppe and forest steppe; shrub and temperate forest; and temperate broadleaved forest, temperate mixed conifer-broadleaved forest, and eurythermic conifer forest; 2) pollen taxa, with low percentages but frequent occurrences, strongly indicate presence in the vegetation; 3) mean annual precipitation (MAP) is the most dominant variable influencing soil-surface pollen assemblages and the most promising climate variable for quantitative reconstructions. Weighted averaging partial least squares regression (WA-PLS), modern analogue technique (MAT), and boosted regression trees (BRT) were used to construct a series of pollen-climate calibration sets. WA-PLS and MAT outperform BRT under leave-one-out cross-validation. WA-PLS models are less susceptible to spatial auto-correlation than MAT models, making WA-PLS models generally the best choice. Our soil-surface pollen data will contribute to modern pollen data in eastern Asia.

POSSIBILITIES OF CATCHMENT’S TRANSPIRATION ASSESSMENT BASED ON SAP FLOW MEASUREMENTS: THE PROBLEM STATEMENT

Study of seasonal dynamics and evapotranspiration volume of forested catchments (mainly forest stand transpiration) is the relevant objective for fundamental knowledge and practical applications. However, there are many difficulties: labor efforts of direct observations, many factors affecting against each other, observational data scaling and so on. As a result, evapotranspiration during hydrological modeling is determined by the leftover principle and simplified techniques, leading to wrong representation of water balance structure. The presented article deals with the first results of our research group focused on setting up field measurements of xylem sap flow using trunk sap flow measuring sensors as well as development of sap flow assessment methods for individual trees and whole catchment. The investigations were performed for mixed coniferous-broad leaved forests at the territory of the Central Sikhote-Alin’ within Verkhneussuriyskiy biogeocenotical station of FSC of the East Asia Terrestrial Biodiversity FEB RAS. This site is used for water balance measuring surveys from 2011. Sap flow was measured continuously during June-October of 2019 on one of the local dominant tree species. Apparently, such investigations are novel for the Russian Far East region. It is expected that direct sap flow measurements for individual trees refinement methods, data scaling and its integration to the hydrometeorological observations will help to make a comprehensive analysis of catchments water balance and to integrate measured data into hydrological models.

РАЗНООБРАЗИЕ СЕЛЕКЦИОННЫХ ФОРМ ЕЛИ ПО СТРОЕНИЮ КОРЫ В ПРИКАМЬЕ

Lately in many countries of the world there has been a massive drying up of spruce stands. Bark form testifies to trees stability to environmental unfavorable factors. Investigations were underway in the central part of Russia, in the zone of coniferous-broadleaved (mixed) forests of Permsky kray. Above scientists established that in the Permsky kray spruce trees with smooth, scaled and longitudinally fissured fracture bark types can be found. The purpose is to determine spruce selective forms the most stable for drying off according to their bark structure. Based on the materials of 9 sample plots, it was established that the sanitary condition of the spruce trees in all the investigated spruce stands was unsatisfactory. According to investigation data in all the SP stands there are dried off trees whose number a varied from 28.4 to 69.6 %. The results of investigations have shown that in stands of all sample plots specimen of spruce with scaled bark form are prevailed. The number of spruce trees with scaled bark varies from 83.1 to 98.9%. Rarely are spruce trees with longitudinally fissured and smooth bark types. We succeeded in singling out a new spruce form according bark structure – smooth warty form too. Share of spruce trees with this bark type does not exceed 4.2 % on stocking. Spruce trees of all the bark forms are subjected significantly to drying off, except the trees with smooth warty form. The conservation of spruce trees with a smooth warty bark form is 100 % on all SP within which specimens of spruce of this bark form were found.

Relationship between forest city landscape pattern and thermal environment: A case study of Longquan City, China.

The differentiation characteristics of landscape pattern affect the urban thermal environment. In this study, temperature characteristics of nine types of landscape in a national forest city, Longquan City, were analyzed by temperature inversion method and spatial analysis. The landscape pattern analysis method was used to explore the correlation of landscape metrics and the thermal environment from 1 km to 3.5 km. The results showed that the high and sub-high temperature zones of Longquan City were distributed in northeast-southwest, mainly composed of urban and rural residential areas. The low and sub-low temperature zone were mainly distributed in the northwest and southeast areas, mainly composed of public welfare forests. By calculating the mean land surface temperature of each landscape type in the area below 700 m above sea level, the temperature of coniferous forest, broadleaf forest, conifer-broadleaf forest, bamboo forest and water was relatively low, whereas that of shrub land, other forest land, cultivated land and construction land was relatively high. Through the analysis of landscape pattern and thermal environment, it was found that the class pattern index was more practical than the landscape pattern index. The correlation between thermal environment effect and construction land distribution reached 0.835, coniferous forest land, broadleaf forest land, coniferous-broadleaf forest land and water were the second, up to -0.5 to -0.4. The cooling effects of different forest types vaied across different spatial scales. Broadleaved forests and coniferous-broadleaved forests were more conducive to cooling at large scales. The larger the area and volume stock of forest land, the more likely it had the lowest land surface temperature.

Effects of simulated acid rain on soil respiration and its component in a mixed coniferous-broadleaved forest of the three gorges reservoir area in Southwest China

BackgroundSoil respiration in forest ecosystems is an important part of the forest carbon (C) cycle. Studying the variation patterns of soil respiration under acid rain conditions is critically important for understanding forest C balance and performing rational forest management and operations.MethodsA split-plot design field experiment was performed in a mixed coniferous-broadleaved forest in the Three Gorges Reservoir Area of Jinyun Mountain, Chongqing from January 2016–January 2018. There were 4 main blocks; each was split into untrenched (UT) and trenched (T) treatments. Treatments with four gradient pH levels of 4.5 (control), 4.0, 3.25 and 2.5 were randomly assigned to the untrenched and trenched treatments. The soil CO2 fluxes, soil temperature, and soil moisture content were evaluated under simulated acid rain. Additionally, the effects of soil properties (soil pH, organic C, C:N ratio, microbial biomass, and enzyme activity) on soil respiration were analysed.ResultsThe soil CO2 fluxes exhibited seasonal variation trends. The annual mean soil respiration rates of the UTCK (control), UT4.0, UT3.25, and UT2.5 treatments in untrenched plots were 1.91, 1.91, 1.77, and 1.74 μmol∙m− 2∙s− 1 in 2016 and 1.91, 1.81, 1.55 and 1.37 μmol∙m− 2∙s− 1 in 2017, respectively. The annual mean heterotrophic respiration rates of the TCK (control), T4.0, T3.25, and T2.5 treatments in the trenched plots were 1.39, 1.32, 1.19 and 1.14 μmol∙m− 2∙s− 1 in 2016 and 1.28, 1.18, 1.02 and 0.83 μmol∙m− 2∙s− 1 in 2017, respectively. Acid rain had a significant cumulative effect on soil respiration and heterotrophic respiration (P < 0.01). In 2016, soil respiration was similar in the UTCK versus the UT4.0 treatment but significantly inhibited under higher acidity. In 2017, soil respiration and heterotrophic respiration were significantly decreased by simulated acid rain. The treatments increased the temperature sensitivity of soil respiration but did not significantly affect the soil temperature or moisture content (P > 0.05); moreover, they significantly increased the soil organic C content and C:N ratio, lowered the hydrolysable N and total P concentrations, and lowered the soil pH and fine root biomass at a later experimental stage. Urease and sucrase activities were significantly reduced in the higher-acidity treatments. Soil respiration rate was significantly positively correlated with the soil pH, fine root biomass, and urease and sucrase activity and significantly negatively correlated with the soil organic C and C:N ratio.ConclusionsAcid rain had a significant cumulative and inhibitory effect on soil respiration and heterotrophic respiration, while soil temperature and moisture had a limited effect on soil respiration under simulated acid rain. The variation in soil properties (e.g., soil organic C, C:N ratio, and fine root biomass) caused by acid rain inhibited the microbial utilization of substrates, which was the main cause of the respiration differences.

Carbon Stock in Sandy and Loamy Soils of Coniferous–Broadleaved Forests at Different Succession Stages

A comparative assessment of the carbon stock in loamy soils (Albic Retisols) of coniferous–broadleaved forests on the Moskvoretsko-Oksky Plain and sandy soils (Albic Podzols) in the Bryansk region is given. The carbon accumulation in soils is related to the texture of their mineral horizons and biotic factors, such as the quality of litter and activity of earthworms. The forests on sandy soils were characterized by a high carbon stock in the plant litter, which is explained by the low biomass of earthworms. The carbon content was significantly higher in the mineral horizons of loamy soils owing to high share of fine particles. The carbon stock in the litter and mineral horizons of loamy and sandy soils turned out to be comparable, except for the sandy soils of mixed forests due to higher clay content. In the course of succession of the coniferous-deciduous forests on the loamy soil, the carbon accumulation in the litter was high only at the late stage due to the high input of spruce needles. The carbon stock in the humus horizons of the loamy soils varied due to changes in their density, which was regulated by earthworms. When comparing different succession stages/types of the forests on sandy soils, it was found that the carbon stock in the litter of the pine forests at the early stage of succession was significantly higher than that of the mixed and broadleaved forests. Trends of carbon accumulation in the mineral horizons of sandy soils were mainly explained by their thickness, which was related to the amount of percolating precipitation regulated by woody plants.

Northwest Caucasus forest spreading evaluation by GIS modeling and historical and geographic data analysis

The article presents the results of the GIS modeling of the potential areas of the Northwest Caucasus coniferous and broad leaved forest stand dominants (Abies nordmanniana, Carpinus betulus, Fagus orientalis, Picea orientalis, Quercus species). The constructed models demonstrate the significantly wider potential areas of these species as compared with the real ones and the almost complete coincidence of the potential areas of dark coniferous tree species A. nordmanniana and P. orientalis. The precipitation parameter in the driest month of the year, altitude above the sea level and temperature seasonality make the greatest contribution to the construction of GIS models of the modern area of the dark coniferous and broad leaved tree species. The analysis of the materials on the natural resource management history demonstrated that it is not the climatic changes, but the anthropogenic changes, that has been the main cause of the reduction of the area of the coniferous-broad leaved forests of the Northwest Caucasus since the middle of the 19th century. The northern boundary of the forest belt has shifted significantly from the plains and foothills to the foothill and mountain areas as a result of the economic and military development of the area.

Environmental and geodynamic settings of the earliest hominin migration to the Arabian-Caucasus region: A review

Majority of researchers consider the Arabian-Caucasus region as a corridor for migration of earliest hominins from their African motherland to Eurasia. The paper is devoted to geological position of main stratified localities of the earliest Paleolithic industries in the Arabian-Caucasus region and estimation of environment of creators of these industries. The following early Paleolithic localities are analyzed: ‘Ubeidiya in Israel, middle Orontes River, Halabiyeh-Zalabiyeh area in the Euphrates River valley, and Ain al Fil in Syria, Dursunlu in Central Turkey, Sambayat, Bostancik, Eskimalatya, and Kovancilar in Eastern Turkey, Karakhach, Muradovo, Agvoric, and Jradzor in NW Armenia, Dmanisi in Southern Georgia, the Azykh cave in Nagornyi Karabakh, Muhkai II in Dagestan, and Kermek in the Taman Peninsula. The evolution of large and small mammals and palynological data on changes of vegetation from the Late Pliocene to the early Middle Pleistocene are studied to determine the age of the earliest Paleolithic industries and climatic conditions of that epoch. Combined analysis of paleontological, paleomagnetic and radio-isotopic data and geological correlation of the sections available for the Halabiyeh-Zalabiyeh, Sambayat, Kovancilar, Karakhach, Dmanisi, Muhkai II, and Kermek localities shows that their age is ranged in time interval ca. 2.0–1.7 Ma. The 1.7–1.6 Ma age of the lowest layers of ‘Ubeidiya with Oldowan-type artefacts probably marks the end of this epoch. Removal of topographic effects of the late Calabrian and younger tectonic uplifts and offsets on major strike-slip faults shows that the topography of the late Gelasian – early Calabrian was much lower and less differentiated and main river systems were more passable than in the present time. The climate of the end of Gelasian was wet and relatively warm, with meadow-steppe and forest-steppe savanna-type vegetation in basins and valleys and coniferous and coniferous–broad-leaved forests in the mountains. Abundance of vegetation was supported by water resources of numerous rivers, lakes, and springs in the intermountain basins and valleys that were controlled partly by fault activity. This stimulated abundance of herbivorous mammals. In spite of relative aridisation at the beginning of Calabrian, vegetation continued to be freely available for herbivores. Hominin dispersal into the region was supported by rich resources of herbivores during the late Gelasian – early Calabrian time.

Changes in defense traits of young leaves in subtropical forests succession

Plants develop diverse adaptive traits in changeable environments, yet whether plant defense traits change during succession remains unclear. In this study, we investigated the young leaf physical traits (i.e., upright orientation of leaves, trichomes, an enhanced cuticle, and a multilayered epidermis) and leaf color trait (i.e., red pigmentation) of dominant plants in three subtropical forests. These forests included a pioneer forest, a mixed coniferous-broadleaved forest, and a monsoon-evergreen broadleaved forest representing early, middle, and later successional stages, respectively. Our results show that the red color trait in young leaves is related to anti-herbivory defense, and the percentage of species with red young leaves is higher in later than in early succession. Physical defense tends to be weaker for red young leaves than for green young leaves in early and middle successions. In addition, the number of defense traits of young leaves increases with succession. We speculate that young leaves in subtropical forests depend increasingly on multiple defense traits during succession because of the increased biotic stresses and environmental complexity in later succession.

Vegetation and climate changes since the middle MIS 3 inferred from a Wulagai Lake pollen record, Inner Mongolia, Northeastern China

The climate conditions during Marine Isotope Stage (MIS) 3 were similar to present-day conditions, but whether humidity then exceeded present levels is debated, and the driving mechanisms of palaeoclimate evolution since MIS 3 remain unclear. Here, we use pollen data from Wulagai Lake, Inner Mongolia, to reconstruct vegetation and climate changes since the middle MIS 3. The steppe biome is reconstructed as the first dominant biome and the desert biome as the second, and the results show that the vegetation was steppe over the last 43,800 years. Poaceae, Artemisia, Caryophyllaceae and Humulus were abundant from middle to late MIS 3, indicating humid climate conditions. As drought-tolerant species such as Hippophae, Nitraria and Chenopodiaceae spread during MIS 2, the climate became arid. The Holocene is characterized by the dominance of steppe with mixed coniferous-broadleaved forests in the Greater Hinggan Range, and the desert biome retains high affinity scores, indicating that the climate was semi-arid. The climate from middle to late MIS 3 was wetter than in the Holocene; this shift was related to changes in the Northern Hemisphere's solar insolation and ice volume. The humid conditions during MIS 3 were attributed to strong ice–albedo feedback, which led to evaporation that was less than the precipitation. The enhanced evaporation caused by increased solar insolation and decreased ice volume might have exceeded the precipitation during the Holocene and resulted in low effective humidity in the Wulagai Lake basin.

The Dependence of the Productivity of Pine Forests of Moscow Experimental Forestry on Soil Conditions

We have studied the effect of soil conditions on the productivity (site index) of pine forests in the zone of coniferous–broad-leaved forests. The research object is natural pine forests of different productivities related to the effect of soil and ground factors. The research is performed in northeastern Moscow oblast at the Sverdlovsk branch of the Moscow educational–experimental forestry. It is revealed that it is the main soil properties that determine the site index of the studied pine forests, include groundwater level, the thickness of the ungleyed mineral part of soil profile, and humus reserves in the mineral part of soil. Gleying rate, the depth of the gley horizon, the thickness of the organic horizon, and the occurrence of ortsteins and iron-manganese concretions are the most important soil indicators of the water regime, which is closely related to forest productivity (site index). The cluster analysis has enabled us to assign the soil varieties to five groups with respect to their productivity and taxonomic position. These informative soil properties should be included into forest GIS and taken into account when planning forestry measures. The diagnostic model may be used in assessing the potential productivity of forest soils and elaborating measures for the rational use of forest lands.

Forest Litters as a Link in the Carbon Cycle in Coniferous–Broadleaved Forests of the Southern Far East of Russia

Forest litter as a component of the carbon cycle in pine–broadleaved forests of different ages was characterized. Field studies of the forest site of the Primorskaya State Agricultural Academy in the south of the Sikhote Alin Range continued for three years. Multiple sampling of forest litter and plant litter fall and measurements of the CO2 emission from the litter and underlying soil horizons were performed on test plots. The maximum litter pool (14.44 ± 0.86 t/ha) was found in the mature stand of Pinus koraiensis; the minimum litter pool (11.52 ± 0.65 t/ha), in the 80-year-old stand. The carbon stock in the litters amounted to 3.7% of the phytomass carbon. The rate of carbon turnover in the forest litters was relatively low in comparison with that in other regions: the ratio of carbon pools in the litter horizons and annual plant falloff reached 3.5. The winter season provided about 10–25% of the annual plant litter fall. The data obtained in this study describe a part of the carbon cycle and contribute to our understanding of the ecosystem function of climate regulation by valuable forest massifs in the south of the Far East of Russia. In this region, the decomposition of forest litters generates the CO2 flux amounting up to 16% of the total CO2 emission from the soil.