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Climate change means that in many areas in boreal region, the duration and thickness of the winter snow cover is decreasing. Young seedlings are exposed to fluctuating winter temperatures in the absence of protecting snow cover. Responses to winter warm and cold spells were studied with Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth.), and Norway spruce (Picea abies (L.) Karts.) container seedlings in Finland. The frost hardiness of whole seedlings and buds was determined for seedlings sampled directly from outdoor overwintering conditions, after 7-day deacclimation (+5 °C; +7 °C in late March) and deacclimation combined with 7-day reacclimation (− 7 °C) treatments between January and late March. The frost hardiness of buds and whole seedlings in Scots pine was between − 40 and − 30 °C from January to early March. Norway spruces tolerated at least − 50 °C in midwinter, but their frost hardiness in outdoor conditions decreased more rapidly in March than that of Scots pines. Silver birch tolerated − 30 °C in February. During simulated warm spells, the Scots pine and silver birch deacclimated without an ability to reacclimate during simulated cold spells. The buds and whole seedlings of Norway spruces also deacclimated, but they had some ability to reacclimate in February and early March, but not in late March. In Nordic boreal conditions, one-year-old Scots pines and silver birches respond strongly to fluctuating winter temperatures during snowless winters, whereas Norway spruces can tolerate typical winter temperatures in midwinter, but their frost hardiness may reduce during warm spells in March. [ABSTRACT FROM AUTHOR]

Trees affect the biotic and abiotic properties of the soil in which they grow. Tree species-specific effects can persist for a long time, even after the trees have been removed. We investigated to what extent such soil legacies of different tree species may impact tree seedlings in their emergence and growth. We performed a plant–soil feedback experiment, using soil that was conditioned in plots that vary in tree species composition in Białowieża Forest, Poland. Soil was taken from plots varying in proportion of birch, hornbeam, pine, and oak. In each soil, seeds of the same four target species were sown in pots. Seedling emergence and growth were monitored for one growing season. To further explore biotic implications of soil legacies, ectomycorrhizal root tip colonization of oak, a keystone forest species, was determined. We found no effect of soil legacies of tree species on the emergence measures. We, however, found a clear negative effect of pine legacies on the total biomass of all four seedling species. In addition, we found relationships between the presence of pine and soil fertility and between soil fertility and root tip colonization. Root tip colonization was positively correlated with the biomass of oak seedlings. We conclude that tree species can leave legacies that persist after that species has been removed. These legacies influence the growth of the next generation of trees likely via abiotic and biotic pathways. Thus, the choice of species in today's forest may also matter for the structure and composition of future forests. [ABSTRACT FROM AUTHOR]

In the Trans-Baikal Territory, mining enterprises significantly pollute the environment with chemical elements. In these conditions, monitoring the state of the environment, including with the help of indicator plants, is of great importance. Among the woody plants, Gmelin larch (Larix gmelinii (Rupr.) Kuzen.) and silver birch (Betula pendula Roth.) are the most common in the region. Using the example of the Bystrinskoe Cu–Au–Fe skarnporphyry deposit, the concentrarion of 46 chemical elements in the needles of Gmelin larch and the leaves of silver birch, as well as the content of these elements in the soil, has been studied. The aim of the study is to identify plant species differences in the accumulation of elements and the prospect for using plants as indicators of environmental pollution. Scientific work has been carried out on 11 sample plots in natural plant communities near the enterprise’s facilities in August 2022. Soil and plant samples have been collected at the same time, at the same sites. The chemical analysis of the samples has been carried out using the “Methodology for measuring the metal content in solid objects by inductively coupled spectrometry” (FER 16.1:2.3:3.11–98). Differences in the concentration of elements in plants in relation to the clarke of terrestrial plants have been established. A statictically significant higher concentration of K, Ca, P, Mg, Fe, Ba, Zn, Na, Rb, Ni, Co, Ga, Sn, Y, Zr, Cd and Nb has been found in birch leaves compared to larch needles, and, conversely, a higher concentration of Sc, W and Hg – in larch needles than in birch leaves. Significant differences between plants have been established in the biological absorption coefficient of Se, P, Sn, Ca, Mn, Sr, Cd, Mg, K, W, Ni, Zn, Sc, Rb, Na and Nb. Knowledge about the peculiarities of accumulation of chemical elements in plant organs can be used for biomonitoring environmental pollution and, possibly, for phytoremediation of contaminated soils.

In the work, the relationship (FA) of the leaves of the hanging birch Betula pendula Roth with atmospheric pollution, climatic indicators and soil characteristics was determined. We analyzed data obtained from 10 sites located in the main geographical directions from the city of Ukhta (Komi Republic, Russia). FA was based on 5 morphological parameters (n=100). In the soil, we determined the pH (water and salt extracts), the content of organic matter and mobile forms of metals. Information on air pollution and climate parameters was obtained from open sources. We established high FA of B. pendula at all sites (0.064-0.076). It was shown that this is not related to the geographical location of the birch growing area. There was no excess of standards of pollutants in the air and soil at the sites. Correlation analysis showed that FA increases in response to a decrease in the proportion of organic matter in the soil and an increase in soil acidity (r is -0.49 and -0.42, respectively). Also, the increase in FA is associated with the content of mobile forms of Pb, Mn, Cu (r is 0.6, 0.36, 0.35, respectively). We found no effect of the content of mobile Zn, Fe, Cd in the soil on the FA level of the leaves. Thus, it is shown that soil characteristics affect the asymmetry of the bioindicator plant, including within environmental regulations. This fact should be taken into account when interpreting the results of the assessment of the ecological state of the territories.

Background and purpose: Osteoarthritis is the most common joint disease in humans, the main symptoms of which are joint pain and dryness. On the other hand, the knee is the most common joint affected by osteoarthritis. The main goals in the treatment of this disease are to reduce pain restore function and improve the patient's quality of life. In many parts of the world, non-steroidal anti-inflammatory drugs are used as the first-line treatment for osteoarthritis. However, researchers are still investigating herbal and alternative treatments. Therefore, this research aimed to make a local herbal lipogel that can be effective in improving the symptoms of osteoarthritis. Materials and methods: This study was a double-blind randomized clinical trial study. Seventy patients were randomly selected from those who were referred to the rheumatologist's office and were diagnosed with osteoarthritis and ruled out systemic rheumatism diseases by observing the entry and exit criteria. The patients had been referred to the doctor for the treatment of 1st and 2nd-degree osteoarthritis and after explaining to them the objectives of the study, after obtaining written consent, they entered the study and were divided into two groups receiving lipogel Arthrohil (35 people) and receiving lipogel placebo (35 people) were divided. To prepare plastic base gel, first, 5% low-density polyethylene (LDPE) was added in 95% liquid paraffin and it was indirectly heated at 130°C for three hours. Then we cooled it very quickly to form a plastic base gel. The gel obtained from Plastibase was investigated in terms of physical stability in ambient and refrigerator temperatures, in terms of occurrence of turbidity, syneresis phenomenon, appearance change of consistency, and pH. The extracts of each of the plants Turmeric (2%), Betula (4%), and Marmaki (4%) were added separately to the gel base and mixed until the gel reached the appropriate consistency. Lipogel was used topically for two months twice a day each time in the amount of two knuckles on each joint. The results of the WOMAC and VAS questionnaires were collected before the treatment, at the end of the first month, and the end of the second month after the treatment. The significance level of the tests was considered P

The actual study is the description of the biochemical characteristics of a wide range of enzymes (phenylalanine ammonia lyase, superoxide dismutase, catalase, peroxidase, polyphenol oxidase) and metabolites (malondialdehyde, phenols, extractives, cellulose, lignin), as well as the profiles of their activities during the xylem structural elements' formation during the predominance of differentiation processes during straight-grained wood formation or proliferation while the figured wood formation in the radial row cambial zone (Fraction 1)—differentiating xylem (Fraction 2)—mature xylem (MX) in the period of active cambial growth in 16-year-old straight-grained Betula pendula var. pendula and figured Betula pendula var. carelica plants. We generalized the processes associated with abnormal xylogenesis were separated spatially, and, to the greatest extent, the metabolism of the studied birch forms differed in the Fraction 2, while the diagnostic contribution of secondary metabolism enzymes and malondialdehyde (MDA) probably characterized the active secondary metabolism of parenchyma cells, which formed figured wood basis. This study described for the first time the biochemical features of a wide range of enzymes and metabolites as well as the profiles of their activities in the xylem structural elements' formation. The necessity of separately analyzing all tissue complexes was proven. This approach made possible to separate the generally observed biochemical patterns spatially. Thus, during the active cambial growth period in 16-year-old B. pendula var. pendula and B. pendula var. carelica, the differences between straight-grained plants and Karelian birch plants (non-figured and figured trunk parts) were most clearly expressed in the differentiating xylem. [ABSTRACT FROM AUTHOR]

A dataset collected from central South Finland was used to investigate the mortality of boreal trees. The mortality rate was found to be the order of three times that predicted by earlier Nordic mortality models, being in the upper range of international literature observations. Small subpopulations of any tree species tend to die out. The mortality of downy birch increases with stand basal area, as well as with stand age. The mortality of Norway spruce and silver birch increases after 100 years, while that of Scots pine is invariant to age. It is suspected that the high mortality of conifers is due to climatic phenomena of anthropogenic origin. As the relative loss rate of basal area is insensitive to stand basal area, the mortality of trees does not strongly regulate thinning practices, but stand-replacing damage can be avoided by retaining a larger timber stock, along with an enhanced proportion of deciduous trees. [ABSTRACT FROM AUTHOR]

Accurate knowledge of site conditions and their effects on regeneration establishment is important for selecting the most appropriate tree species and regeneration methods for a given regeneration site. This study examined the response of the first-year field performance of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth.) seedlings in boreal forests to variables available in open forest and natural resources datasets. Survival, height increment and damage of planted tree seedlings and the success of direct seeding of pine were analysed on a total of 284 plots (1000 m2) in 18 regeneration experiments established in 2020–2022 in southern and central Finland. The height increment of silver birch was higher than that of conifers, while the lowest mortality rate was found for spruce. In the generalised linear mixed models, topographic wetness index, soil texture, site type and growing stock at clearcut explained the species-specific survival and height increment of planted seedlings and the success of pine seeding. Low-cost, open geospatial data effectively provide useful details on the site conditions suitable for diversifying tree species composition in boreal forests instead of monocultures. [ABSTRACT FROM AUTHOR]

Background and purpose: Osteoarthritis is the most common joint disease in humans, the main symptoms of which are joint pain and dryness. On the other hand, the knee is the most common joint affected by osteoarthritis. The main goals in the treatment of this disease are to reduce pain restore function and improve the patient's quality of life. In many parts of the world, non-steroidal anti-inflammatory drugs are used as the first-line treatment for osteoarthritis. However, researchers are still investigating herbal and alternative treatments. Therefore, this research aimed to make a local herbal lipogel that can be effective in improving the symptoms of osteoarthritis. Materials and methods: This study was a double-blind randomized clinical trial study. Seventy patients were randomly selected from those who were referred to the rheumatologist's office and were diagnosed with osteoarthritis and ruled out systemic rheumatism diseases by observing the entry and exit criteria. The patients had been referred to the doctor for the treatment of 1st and 2nd-degree osteoarthritis and after explaining to them the objectives of the study, after obtaining written consent, they entered the study and were divided into two groups receiving lipogel Arthrohil (35 people) and receiving lipogel placebo (35 people) were divided. To prepare plastic base gel, first, 5% low-density polyethylene (LDPE) was added in 95% liquid paraffin and it was indirectly heated at 130°C for three hours. Then we cooled it very quickly to form a plastic base gel. The gel obtained from Plastibase was investigated in terms of physical stability in ambient and refrigerator temperatures, in terms of occurrence of turbidity, syneresis phenomenon, appearance change of consistency, and pH. The extracts of each of the plants Turmeric (2%), Betula (4%), and Marmaki (4%) were added separately to the gel base and mixed until the gel reached the appropriate consistency. Lipogel was used topically for two months twice a day each time in the amount of two knuckles on each joint. The results of the WOMAC and VAS questionnaires were collected before the treatment, at the end of the first month, and the end of the second month after the treatment. The significance level of the tests was considered P<0.05. Results: The studied patients were in the age range of 40 to 73 years. The prepared herbal lipogel can be used for clinical tests in terms of microbial control and it contained 0.03% of total flavonoid and 0.1027% of total phenol. The stability of herbal lipogel was more than 94%. According to the WOMAC questionnaire, compared to placebo, herbal lipogel significantly reduced pain, joint stiffness, and movement disorder in osteoarthritis patients (P<0.05). The results of the Friedman test, to compare the scores of the VAS questionnaire before the start of the treatment, at the end of the first month, and at the end of the second month showed that after the treatment with herbal lipogel, the amount of pain felt by the patients decreased significantly (P<0.05). Conclusion: By comparing the scores obtained from the WOMAC and VAS questionnaires in the placebo and herbal lipogel groups, we found that the topical use of herbal lipogel has been effective in increasing the performance and pain control of patients with osteoarthritis, which is due to the antioxidant and anti-inflammatory properties of the compounds. In this lipogel, it seems obvious. [ABSTRACT FROM AUTHOR]

Autumn senescence is characterised by spatial and temporal heterogeneity. We show that senescing birch (Betula spp.) leaves had lower PSII activity (probed by the FV/FM chlorophyll a fluorescence parameter) in late autumn than in early autumn. We confirmed that PSII repair slows down with decreasing temperature, while rates of photodamage and recovery, measured under laboratory conditions at 20°C, were similar in these leaves. We propose that low temperatures during late autumn hinder repair and lead to accumulation of non-functional PSII units in senescing leaves. Fluorescence imaging of birch revealed that chlorophyll preferentially disappeared from interveinal leaf areas. These areas showed no recovery capacity and low non-photochemical quenching while green veinal areas of senescing leaves resembled green leaves. However, green and yellow leaf areas showed similar values of photochemical quenching. Analyses of thylakoids isolated from maple (Acer platanoides) leaves showed that red, senescing leaves contained high amounts of carotenoids and α-tocopherol, and our calculations suggest that α-tocopherol was synthesised during autumn. Thylakoids isolated from red maple leaves produced little singlet oxygen, probably due to the high antioxidant content. However, the rate of PSII photodamage did not decrease. The data show that the heterogeneity of senescing leaves must be taken into account to fully understand autumn senescence. [ABSTRACT FROM AUTHOR]

Biodiversity is the basis for the maintenance and functioning of ecosystems. Genetic diversity is at the heart of biodiversity, and therefore an understanding of the current state of plant genetic diversity can contribute to the future provision of sustainable ecological values and services by ecosystems. This study was conducted in the Irtysh River basin (five tributaries) with the dominant species of river valley forests, Betula pendula. Sampling points were set up at approximately 10 km intervals within each tributary using a random sampling method for genetic diversity studies based on chloroplast microsatellite molecular markers. The results indicated that (1) nine alleles were identified in 198 samples. The genetic diversity of Betula pendula was relatively rich in all tributaries (I = 0.216~0.546); genetic diversity was significantly higher in the downstream area of the basin than in the midstream and upstream areas of the basin. Genetic differentiation was at a low level in the tributaries except for the Berezek River, where genetic differentiation was high. (2) Genetic variation was mainly derived from within populations, accounting for 62% of the total genetic variation. The genetic distance was significantly positively correlated with the geographical distance (p < 0.05). The Betula pendula population structure was divided into two major groups. (3) Twelve haplotypes were identified in the basin. The dominant haplotypes in the upper tributaries were H2 and H4, while in the lower tributaries these were H1 and H3. Therefore, this paper suggests the future establishment of a germplasm resource bank for populations of the Berezek River, and the implementation of priority conservation measures for the downstream populations with higher genetic diversity, so as to realize the sustainable ecological value of the valley forests of the Betula pendula. [ABSTRACT FROM AUTHOR]

Silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.) are the two most common broadleaf species in Sweden, together making up approximately 12% of the standing timber volume. The two birch species are usually not distinguished in practice, although they tend to differ in terms of volume production, timber quality, and site preferences. To map the proportion of the two birch species in Sweden's young forests, we used survey data from 123 stands 6–7 years after clearfelling, and data from Sweden's meteorological and hydrological institute. We also examined Sweden's young forests in terms of area, volume, and stem density between 1983 and 2021, using national forest inventory data. Proportions of the two birch species varied significantly across Sweden, and the average temperature sum over the first five years after clearfelling explained 72% of the variation. There was no significant change in area of forest classified as young forest in Sweden, over the last four decades, although there was a significant increase in volume and stem density in Sweden's young forests, with birch making up most of the increase in stem numbers. [ABSTRACT FROM AUTHOR]

Abstract Adventitious root formation is a key step in vegetative propagation via cuttings. It is crucial for establishing birch plantations and preserve birch varieties. Although previous studies have highlighted role of WOX11 in controlling adventitious root formation, no such study has been conducted in birch. Understanding the mechanism of adventitious root formation is essential for improvement of rooting or survival rate using stem cuttings in birch. In this study, we cloned BpWOX11 and produced BpWOX11 overexpression (OE) transgenic lines using the Agrobacterium-mediated plant transformation. OE lines exhibited early initiated adventitious root formation, leading to increase the rooting rate of stem cuttings plants. RNA sequencing analysis revealed that OE lines induced the gene expression related to expansin and cell division pathway, as well as defense and stress response genes. These may be important factors for the BpWOX11 gene to promote adventitious root formation in birch cuttings. The results of this study will help to further understand the molecular mechanisms controlling the formation of adventitious roots in birch.

Adventitious root formation is a key step in vegetative propagation via cuttings. It is crucial for establishing birch plantations and preserve birch varieties. Although previous studies have highlighted role of WOX11 in controlling adventitious root formation, no such study has been conducted in birch. Understanding the mechanism of adventitious root formation is essential for improvement of rooting or survival rate using stem cuttings in birch. In this study, we cloned BpWOX11 and produced BpWOX11 overexpression (OE) transgenic lines using the Agrobacterium-mediated plant transformation. OE lines exhibited early initiated adventitious root formation, leading to increase the rooting rate of stem cuttings plants. RNA sequencing analysis revealed that OE lines induced the gene expression related to expansin and cell division pathway, as well as defense and stress response genes. These may be important factors for the BpWOX11 gene to promote adventitious root formation in birch cuttings. The results of this study will help to further understand the molecular mechanisms controlling the formation of adventitious roots in birch. [ABSTRACT FROM AUTHOR]

We tested three soil scarification approaches of varying intensity (intensive preparation exposing bare mineral soil, medium intensity with a mixture of organic material and mineral soil, and control without site preparation) on six clear-felled sites in two localities in northern and central Sweden between 2018 and 2021. The effect of soil scarification intensity and soil moisture on the occurrence of naturally regenerated birch seedlings was tested one, two and three years after soil scarification, and the density of direct-seeded birch seedlings one year after seeding. In addition, we tested the effect of the annual seed rain, and differences between the two birch species, on the density of direct-seeded seedlings. Soil scarification and its interaction with soil moisture had a significant positive effect on both the occurrence of naturally regenerated birch seedlings and the density of direct-seeded birch seedlings. There was no significant effect of neither annual natural seed rain nor species choice on direct-seeded seedling density. Time since soil scarification had a significant effect on the occurrence of naturally regenerated birch seedlings. In moist soils with high volumetric water content (≥ 28%), birch seeds germinate at high rates and seedlings survive without soil scarification. In mesic soils, birch seeds germinate with higher rates after soil scarification. In dry soils, birch seeds rarely germinate regardless of any disturbance of the humus layer. [ABSTRACT FROM AUTHOR]

Silver birch (Betula pendula Roth) is one of the fast-growing tree species that often colonize abandoned agricultural lands in Europe and the European part of Russia. The purpose of this article is to analyze the spatiotemporal dynamics of Betula pendula crown cover on abandoned arable lands in a zone of broad-leaved forests of the Bashkir Cis-Ural (Russia, Republic of Bashkortostan). The assessment of current and retrospective values of crown cover was carried out using a regression model of the dependence of crown cover on the values of red channel brightness in early-spring images from Landsat 5–8 and Sentinel-2 satellites from 2012–2022. To estimate the number and height of trees, a survey was carried out using a LiDAR camera mounted on a UAV. After calculating the crown cover in grid squares and their distance from the seed source in QGIS, variance analysis was carried out to assess the influence of the factor of distance from the seed source on the crown cover. The influence of the factor of distance from the seed source on the crown cover was higher at earlier stages of overgrowth of abandoned agricultural lands. An exception to this dependence was only one sample plot where the prevailing wind direction was opposite to the direction of seed dispersal. The leading factors affecting the distribution of birch on abandoned agricultural lands were wind direction, height of seed trees, and grazing. In the parts of the sample plots that were furthest away from seed sources, the trees were 1–3 years younger or the same age, and stand density was lower than in sites located closer to the seed trees. In general, the results of the present study indicate two opposite relationships between seedling survival and distance to seed trees: (1) seed fall and seedling density decrease with increasing distance from the seed tree, and (2) the probability of seed/seedling survival increases due to decreased competition. [ABSTRACT FROM AUTHOR]

Summary: Climate warming advances the onset of tree growth in spring, but above‐ and belowground phenology are not always synchronized. These differences in growth responses may result from differences in root and bud dormancy dynamics, but root dormancy is largely unexplored.We measured dormancy in roots and leaf buds of Fagus sylvatica and Populus nigra by quantifying the warming sum required to initiate above‐ and belowground growth in October, January and February. We furthermore carried out seven experiments, manipulating only the soil and not air temperature before or during tree leaf‐out to evaluate the potential of warmer roots to influence budburst timing using seedlings and adult trees of F. sylvatica and seedlings of Betula pendula.Root dormancy was virtually absent in comparison with the much deeper winter bud dormancy. Roots were able to start growing immediately as soils were warmed during the winter. Interestingly, higher soil temperature advanced budburst across all experiments, with soil temperature possibly accounting for c. 44% of the effect of air temperature in advancing aboveground spring phenology per growing degree hour.Therefore, differences in root and bud dormancy dynamics, together with their interaction, likely explain the nonsynchronized above‐ and belowground plant growth responses to climate warming. [ABSTRACT FROM AUTHOR]

Birch tree Betula pendula Roth. is an important ornamental and forest plant, which has a distribution in many parts of the world and has about 40 species. In Turkey, it is frequently encountered in North Anatolia and East Anatolia regions. There are many harmful insect species known to damage birch trees. Samples of the pest species that are the subject of this study were taken from Erzurum Center, Atatürk University Campus, Merkez Teke Stream and Aziziye Campus. The aim of the study is to determine the biology and damage of Nematus (=Croesus) septentrionalis (L., 1758) on birch trees. Samples were collected between 20 June and 20 September 2019 and 2020. A preliminary assessment study was conducted in 2018 to determine the pest's ecology. The adult specimen of the insect was collected from birch trees on sunny days. The larvae were collected by cutting with the help of pruning shears together with the leaves of the branches they ate. Pupae were obtained by digging the soil to a depth of 4 fingers (10-15 cm) with the help of a hoe. The collected adults were placed in jars and killed with ethyl acetate. Dead samples were transferred to a small cardboard box, brought to the laboratory, taped and labeled with the location, size and date of sample collection written on the box. The larvae were placed in a desiccator with the soil at the bottom together with the leaves they will feed on, absorbent cotton moistened with water was left on the ground and fresh leaves were brought to the laboratory every other day to feed and mature the larvae. As a result of the research, spawning time, larval stage and number of generations of Nematus (=Croesus) septentrionalis were determined under natural living conditions. While the number of damaged trees was determined to obtain the parasitism ratio, the damaged leaves on the branches of randomly selected trees were also counted to determine the number of eggs and larvae on the leaves. In this study, the biology of Nematus (=Croesus) septentrionalis and its damage to birch trees were investigated. Useful information has been uncovered for future researchers working on this topic. It was determined that the pest gave one generation per year in Erzurum conditions. [ABSTRACT FROM AUTHOR]

Currently, studies investigating the carbon balance in forest ecosystems are particularly relevant due to the global increase in CO2 content in the atmosphere. Due to natural reforestation over the past 25–30 years, birch (Betula pendula Roth.) forests were extensively grown and established on abandoned agricultural lands in Bashkir Cis-Ural (Republic of Bashkortostan, Russia). The significant positive aspect of reforestation on fallow lands is the carbon sequestration that takes place in the tree phytomass, especially at the growth stage of stand formation. The aim of this article is to test the approach of using a UAV-mounted LiDAR camera to estimate the phytomass and carbon stocks in different-aged birch forests growing on abandoned arable lands in Bashkir Cis-Ural. The methodology was developed using 28 sample plots, where the LiDAR survey was performed using a DJI Matrice 300 RTK UAV. Simultaneously, the stand characteristics and phytomass of stem wood were also estimated, using traditional methods in the field of forest science. The regression equations of phytomass dependence on stand characteristics at different stages of reforestation were constructed using data obtained from LiDAR imagery. It was shown that the above-ground tree biomass could be precisely estimated using the index obtained by multiplying the number of trees and their average height. A comparison of the data obtained using traditional and LiDAR survey methods found that the accuracy of the latter increased in conjunction with stand density. The accuracy of estimation ranged from 0.2 to 6.8% in birch forests aged 20 years and over. To calculate carbon stocks of the above-ground tree stands, the use of regional conversion coefficients is suggested, which could also be applied for the estimation of carbon content in trunk wood and leaves. An equation for the calculation of above-ground biomass carbon stocks of birch forests on abandoned arable lands is proposed. [ABSTRACT FROM AUTHOR]

Mixed forests are known for their ability to provide a wide range of ecosystem services. Such forests have higher biodiversity compared to monocultures, are resilient against disturbances and may mitigate the effects of climate change. Despite well-known benefits, there is still little information on how these forests should be established and managed. The aim of this study was to describe the early growth dynamics of current boreal young mixed stands of planted Norway spruces (Picea abies (L.) Karst.) and naturally regenerated birches (Betula spp.). We collected data from 9 stands planted for spruce 8–14 years ago in Southern and Central Finland. Stem analysis was conducted to 144 spruces and to 144 birches to determine previous growth. We modelled the height and diameter development of individual trees in relation to tree age at stump height using non-linear mixed Chapman-Richards model. There were no significant differences between spruce and seed-origin birch in diameter growth at stump height, but the initial height increments of natural birches were larger than those of planted spruces. However, planted spruces were able to keep up with the height development of birches, if spruces received a head start over naturally regenerated seed-origin birch for two growing seasons. Thus, naturally regenerated birch admixture can be utilized to establish single-storied spruce-birch mixtures, and the admixture should be retained during the early cleaning of planted spruce stands.

Establishing the role of woody species as an instrument for heavy metal bioaccumulation is a relevant issue today in the context of the development of the phytoremediation system. The article presents the results of studies on the influence of different Arsenic (As) concentrations in soil on the development of aboveground biomass in Betula pendula Roth. and Populus tremula L. stands under conditions of reclamation plantings. The studies were conducted in 30 locations of birch and poplar tree plantations within the ore-producing regions of Saxony (Eastern Germany) in soil with different levels of As contamination. The highest As content was noted in the technosoil of the Davidschacht site, where the metalloid content was 229.3 times greater compared with a value in a conditionally uncontaminated area (Großschirma). The values of leaf area index and aboveground biomass obtained in field measurements were presented. The aboveground biomass values in the investigated plantations ranged from 189.9 ±10.16 to 201.8 ± 19.09 t/ha, and leaf area index values ranged from 1.74 ± 0.29 to 2.05 ± 0.16 m2/m2. Sentinel-2A multispectral images were processed for the construction of a map of the aboveground biomass distribution within the region under study. The values of the spectral indices for leaf area index were obtained with subsequent construction of the regression dependence of the aboveground biomass in the plantings on this indicator. The RMSE value for the developed model of the dependence of aboveground biomass on the leaf area index was 17.84 t/ha, which could be considered as satisfactory and can serve as a basis for practical application of the model developed. The inverse trend in relation to locations with different levels of soil contamination with As was determined for the aboveground biomass indicator. Within the region under study, the highest value of aboveground biomass in the stands was found for the area with the lowest As level. The results showed that the correlation coefficient between the highest of the optimal spectral indices, the leaf area index, and the aboveground biomass in B. pendula and P. tremula plantings was statistically significant and approached the value of 0.7. The results presented can become a theoretical basis for monitoring the accumulation of aboveground biomass of tree stands in areas with different levels of soil contamination with As. In perspective, the presented model of biomass estimation based on spectral technologies can serve as an application basis for rapid assessment of the growth and development parameters of forest stands in As-contaminated areas.

Genetic gains realised through silver birch (Betula pendula Roth) seed orchards were studied using data from common-garden trials established at 34 sites in southern and central Finland. The test materials include seedlots representing 19 commercial seed orchards that operated between 1972 and 2009, and 21 natural stands. All the trials were assessed for several growth and quality traits between the ages of 9 and 24. Realised gains were estimated based on univariate linear mixed models with corrections for latitudinal seed transfer effects. Overall, seed orchard materials outperformed unimproved reference materials in all the traits but results for individual seed orchards varied substantially. Stem volume gains ranged from 1.0% to 31.1%. Improved trees had, on average, 6.8% (up to 26.7%) fewer ramicorn branches and 16.2% (up to 57.6%) fewer forks than unimproved trees. Branch and overall quality showed consistently positive gains. More recently established seed orchards performed better than older ones, and seed orchards with fewer clones outperformed those with dozens of clones. "JR-1" and "JR-2" bi-clonal seed orchards fared differently, with "JR-1" showing modest genetic gains and "JR-2" emerging as the top overall performer across all seed orchards. An alternative statistical concept, the D-value, was utilised to assess the magnitude of genetic gain for different scaled, normally distributed traits. Average D-values implied a similar level of improvement for stem volume, branch quality, and forking, and a smaller gain for stem slenderness and the number of ramicorn branches. The results for individual seed orchards suggest a slight trade-off between stem volume growth and branch quality.

Due to their long lifespan, trees and bushes develop higher order of branches in a perennial manner. In contrast to a tall tree, with a clearly defined main stem and branching order, a bush is shorter and has a less apparent main stem and branching pattern. To address the developmental basis of these two forms, we studied several naturally occurring architectural variants in silver birch (Betula pendula). Using a candidate gene approach, we identified a bushy kanttarelli variant with a loss-of-function mutation in the BpMAX1 gene required for strigolactone (SL) biosynthesis. While kanttarelli is shorter than the wild type (WT), it has the same number of primary branches, whereas the number of secondary branches is increased, contributing to its bush-like phenotype. To confirm that the identified mutation was responsible for the phenotype, we phenocopied kanttarelli in transgenic BpMAX1::RNAi birch lines. SL profiling confirmed that both kanttarelli and the transgenic lines produced very limited amounts of SL. Interestingly, the auxin (IAA) distribution along the main stem differed between WT and BpMAX1::RNAi. In the WT, the auxin concentration formed a gradient, being higher in the uppermost internodes and decreasing toward the basal part of the stem, whereas in the transgenic line, this gradient was not observed. Through modeling, we showed that the different IAA distribution patterns may result from the difference in the number of higher-order branches and plant height. Future studies will determine whether the IAA gradient itself regulates aspects of plant architecture. [ABSTRACT FROM AUTHOR]

Pollen production is one plant characteristic that is considered to be altered by changes in environmental conditions. In this study, we investigated pollen production of the three anemophilous species Betula pendula, Plantago lanceolata, and Dactylis glomerata along an urbanization gradient in Ingolstadt, Germany. We compared pollen production with the potential influencing factors urbanization, air temperature, and the air pollutants nitrogen dioxide (NO2) and ozone (O3). While we measured air temperature in the field, we computed concentration levels of NO2 and O3 from a land use regression model. The results showed that average pollen production (in million pollen grains) was 1.2 ± 1.0 per catkin of Betula pendula, 5.0 ± 2.4 per inflorescence of Plantago lanceolata, and 0.7 ± 0.5 per spikelet of Dactylis glomerata. Pollen production was higher in rural compared to urban locations on average for B. pendula (+ 73%) and P. lanceolata (+ 31%), while the opposite was the case for D. glomerata (− 14%). We found that there was substantial heterogeneity across the three species with respect to the association of pollen production and environmental influences. Pollen production decreased for all species with increasing temperature and urbanization, while for increasing pollutant concentrations, decreases were observed for B. pendula, P. lanceolata, and increases for D. glomerata. Additionally, pollen production was found to be highly variable across species and within species—even at small spatial distances. Experiments should be conducted to further explore plant responses to altering environmental conditions. [ABSTRACT FROM AUTHOR]

The JIP test, based on fast chlorophyll fluorescence (ChlF) kinetics and derived parameters, is a dependable tool for studying photosynthetic efficiency under varying environmental conditions. We extracted additional information from the whole OJIP and the normalized variable fluorescence (Vt) transient curve using first and second-order derivatives to visualize and localize points of landmark events. To account for light-induced variations in the fluorescence transient, we present a time-adjusted JIP test approach in which the derivatives of the transient curve are used to determine the exact timing of the J and I steps instead of fixed time points. We compared the traditional JIP test method with the time-adjusted method in analyzing fast ChlF measurements of silver birch (Betula pendula) in field conditions studying diurnal and within-crown variation. The time-adjusted JIP test method showed potential for studying ChlF dynamics, as it takes into account potential time shifts in the occurrence of J and I steps. The exact occurrence times of J and I steps and other landmark events coincided with the times of significant differences in fluorescence intensity. Chlorophyll fluorescence parameters were linearly related to photosynthetic photon flux density (PPFD) at different times of day, and the values obtained by the time-adjusted JIP test showed a stronger linear regression than the traditional JIP test. For fluorescence parameters having significant differences among different times of day and crown layers, the time-adjusted JIP test resulted in more clear differences than the traditional JIP test. Diurnal ChlF intensity data indicated that differences between the southern and northern provenance were only evident under low light conditions. Taken together, our results emphasize the potential relevance of considering the time domain in the analysis of the fast ChlF induction. [ABSTRACT FROM AUTHOR]

Applying arginine-phosphate (AP) to tree seedlings at planting is a novel silvicultural practice in Northern Europe to improve the success of forest regeneration. We present three case-studies of the potential advantages of adding AP at planting on the establishment and damage susceptibility of seedlings in pure and mixed plantings of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst. ) and silver birch (Betula pendula Roth) over two years in the field. Location of study sites were in southern (S), northeastern (NE) and northwestern (NW) Sweden. The main agents of damage were pine weevil (Hylobius abietis L.) on conifers at the south site, browsing of birch at all sites and browsing/other top damage to conifers at the north sites. The effect of adding AP varied between the sites. It was positive for survival of pine at site S, despite considerable damage by pine weevil. However, at the S site more of the surviving spruce and birch were browsed when treated with AP. At the NE site AP-treatment had positive effects on conifer growth. At the NW site adding AP positively affected survival and growth of all three species, and AP-treated seedlings of all species were less browsed than untreated seedlings. AP treatment presents a potential tool to improve the success of forest regeneration, especially when establishing pine stands in south Sweden.

The reasons for distortion of the results of assessment of fluctuating asymmetry of woody plants are examined by the example of the silver birch Betula pendula Roth. The results of assessment of the fluctuating asymmetry by researchers with different skill levels in using this method are presented; it is shown that, for researchers without any experience in using this method, it is typical to overestimate the results by up to 50%, while training provides similar results. When assessing the environmental health by the magnitude of fluctuating asymmetry, it is necessary to comply with the method requirements for material collection and processing; noncompliance can lead to problems with the interpretation of the results. [ABSTRACT FROM AUTHOR]

Inonotus obliquus, a wood-decaying mushroom, has been used as a health-promoting supplement and nutraceutical for centuries. It is a source of bioactive compounds accumulated in both the conks (pseudosclerotia/sclerotia) and the biomass obtained in vitro. This study aimed to qualitatively and quantitatively analyze the bioelements and selected metabolites produced in mycelial cultures obtained from different host species. The mycochemical potential of mycelial cultures isolated from pseudosclerotia grown in Betula pendula, Alnus glutinosa, and Carpinus betulus was compared. Parent cultures were obtained in two types of medium (malt extract agar substrates without and with birch wood). Experimental cultures were developed in 2 L bioreactors for 10 days. The content of bioelements was determined using FAAS and FAES methods. Organic compounds were estimated using the RP–HPLC–DAD method. The cytotoxicity of the extracts was evaluated in human keratinocytes HaCaT, human skin fibroblasts BJ, human liver cancer HepG2, human melanoma A375, and mouse melanoma B16-F10. The extracts showed the presence of bioelements: sodium, potassium, magnesium, calcium, zinc, manganese, iron, and copper; phenolic acids: p-hydroxybenzoic, caffeic, p-coumaric, and protocatechuic; sterols: lanosterol, ergosterol, ergosterol peroxide; triterpene compounds: betulin, betulinic acid, inotodiol; indole compounds: L-tryptophan, tryptamine, 5-methyltryptamine, melatonin. The content of bioactive substances in the biomass was dependent on both the origin of the host species of the fungus isolate and the type of culture medium. Based on the results of this study, mycelial cultures can be proposed as a potential source of bioactive compounds and are promising naturally derived cytotoxic agents. [ABSTRACT FROM AUTHOR]

South rear-edge populations of widely distributed temperate and boreal tree species such as birches (Betula pubescens and Betula pendula) are considered particularly vulnerable to climate warming, and at the same time, they constitute genetic reservoirs of drought-adapted ecotypes. Here, we compared radial growth patterns and responses to climate, river, or reservoir flows and a drought index of rear-edge (southernmost) populations (Toledo Mountains, central-southern Spain) with populations located in northern Spain of B. pubescens and B. pendula. Then, we performed a comparative analysis across Europe of B. pendula populations. The main climatic constraint of birch growth was a high summer water deficit, although the effect of local hydrological conditions was particularly important in rear-edge populations. We found declining growth trends in rear-edge stands dating from the early 21st century, related to decreasing water availability and increasing aridity. Our results also suggested distinct growth patterns and climate-growth associations of B. pendula across Europe that show how populations further south and in warmer locations were more sensitive to drought stress. Drought-induced growth decline can be exacerbated by local human land uses, leading to reduced river inflow, thus endangering birch populations at their southern distribution limit. Protection of threatened rear-edge birch populations requires adequate management of local water resources. [ABSTRACT FROM AUTHOR]

Due to the global increase in CO2 in the atmosphere, studies focusing on the carbon balance in forest ecosystems are currently particularly relevant. Abandoned agricultural lands could provide an important contribution to carbon sequestration in many parts of the world. In the broad-leaved forest zone of the Cis-Ural (Southern Ural region, Russia), the carbon sequestration dynamics in the biomass of woody and herbaceous plants, as well as in the litter and soil on abandoned arable lands repopulated with silver birch (Betula pendula), was studied. The data were collected on 35 round (with diameter of 30 m) sample plots located within communities representing the different stages of reforestation with tree stands aged 3 to 30 years. It was found that the carbon content of the stem wood and herbaceous understory did not depend on the succession stages, which largely corresponds to the literature data. The carbon content in root biomass and soil organic matter increased along with the growth of tree stands. While the forest stand grew, the carbon content in the grey forest soil increased from 2.5 to 4.4%, and in the more fertile dark grey forest soil it changed only slightly. The carbon deposition by the forest stands on the sample plots located on the dark grey forest soils was higher than on grey forest soils. The average rate of carbon sequestration in the tree stand was 2.7 t/ha/year. Most mature, 25–30-years-old silver birch tree stands provided the highest average annual increase in tree biomass and the rate of carbon sequestration evaluated was 9 t/ha/year. Also, the carbon pool in the 30 cm soil layer was 2.7 times greater than in the tree stand. It was concluded that abandoned agricultural lands overgrowing by forest in the Cis-Ural are promising for carbon sequestration. [ABSTRACT FROM AUTHOR]

• 38 strains of endophytic fungi were isolated from silver birch. The presence of Betulin and Betulinic acid was confirmed in 32 isolates. • The highest amount of betulin in Fusarium cicatricum (311.604 mg/ml) and Penicillium citrinum (409/381 mg/ml) and the highest amount of Betulinic acid in Alternaria alternate (431.275 mg/ml) was found. • Cellulose nanofibers increased the amount of terpenes by 27.5 and 8 times respectively in P. citrinum and F. fuckelii compared to the control. This study specifically aims to produce Betulin and Betulinic acid derivatives, which are anticancer terpenes by endophytic fungi isolated from the bark of silver Birch (Betula pendula Roth) for the first time. Betulin can be converted or decomposed into its derivatives over time, but all these derivatives are known, as terpenes how, are exciting prospects for application in medicine and cosmetics. In order to carry out this research, bark samples were collected from silver birch trees in Siahmarzkooh – Golsetan – Iran. Samples were cultured in potato dextrose agar (PDA) after surface sterilization. Thirty-eight endophytic fungi were isolated. The ability of Betulin and Betulinic acid induction by endophytic fungi was measured by HPLC and three isolates with the highest amount were selected and molecularly recognized (PCR-sequencing). In the next step, elicitors were induced into 2-year-old mycelium reserves of birch endophytic fungi. The cultures were extracted with three concentrations and three different times of cellulose nanofibers and sodium nitrate, and the changes of terpenes were measured by HPLC. The results showed that 32 of 38 isolates have terpene. Fusarium fuckelii (311.604 µg/mL), Penicillium citrinum (381/409 µg/mL) had the highest amount of Betulin, and Alternaria alternate (431.275 µg/mL) had the highest amount of Betulinc acid. The results reconfirmed the conversion of Betulin into its derivatives over time. Cellulosic nanofibers had a more significant effect on the increase of terpene as an elicitor, so 100 mg/L of it induced 27.5 and 8 times in P. citrinum and F. fuckelii , respectively, compared to the control. This study showed that the endophytic fungi isolated from the silver birch trees could produce, increase terpenes, and probably can be more easily used in the cosmetic or pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the current state of silver birch (Betula pendula Roth.) stands in Ukrainian Polissya, as well as to identify optimal composition resulting in productive and resilient mixed birch forests. It was found that in forests managed by the State Forest Resources Agency of Ukraine, birch stands grow on an area of 352 800 ha, covering 5.6% of the total area of forests in Ukraine. Within the study region of Ukrainian Polissya, birch stands cover 294 900 ha making 12.3% of the total forest area. Naturally originated birch stands were found to dominate in the study region, with 65.4% of vegetative stands and 25.2% of those grown from seeds. However, planted stands significantly prevail in terms of growing stock as compared to natural ones. In Ukrainian Polissya, silver birch trees grow as a part of mixed pine and birch forests on 632 400 ha. Our study found that mixed pine and birch stands with 80-90% of Scots pine and 20-10% of silver birch in the composition are the most productive.

In plants, phase change from the juvenile stage to maturity involves physiological and anatomical changes, which are initiated and controlled by evolutionary highly conserved microRNAs. This process is of particular significance for the in vitro propagation of woody plant species, as individuals or tissues that have undergone the transition to vegetative maturity are recalcitrant to propagation. Conserved miRNAs differentially expressed between juvenile (including rejuvenated) and mature silver birch tissues were identified using high-throughput sequencing of small RNA libraries. Expression of some miR156 isoforms was high in juvenile tissues and has been previously reported to regulate phase transitions in a range of species. Additional miRNAs, such as miR394 and miR396, that were previously reported to be highly expressed in juvenile woody plant tissues were also differentially expressed in this study. However, expression of miR172, previously reported to be highly expressed in mature tissues, was low in all sample types in this study. The obtained results will provide insight for further investigation of the molecular mechanisms regulating vegetative phase change in silver birch and other perennial woody plant species, by analysing a wider range of genotypes, tissue types and maturation stages. This knowledge can potentially assist in identification of rejuvenated material at an earlier stage than currently possible, increasing the efficiency of silver birch in vitro propagation. [ABSTRACT FROM AUTHOR]

Interest in the cultivation of mushrooms, including medicinal mushrooms like Chaga (Inonotus obliquus) has increased in recent years. To provide commercial cultivators with vigorous and productive strains of I. obliquus, 38 strains were isolated from the conks in Estonia and Finland. The growth rates of these isolates were determined on Malt Extract Agar (MEA), and on wood sticks of Betula pendula, B. pubescens, Alnus incana and A. glutinosa. Growth rates differed for the various isolates, depending on temperature as well as substrate. On the MEA at 9°C the fastest-growing strain of I. obliquus was PAT21061, at 18°C PAT22871 and at 22°C PAT21058. On B. pendula, the I. obliquus strain, PATKJ180 had the highest growth rate; on B. pubescens, PAT21061; on A. glutinosa, PATKA880; and on A. incana, PATKA2679 exhibited the highest growth rate. But the growth rate characteristics of I. obliquus were not correlated with the host species origin of the fungus isolate. Still, the ability of strains to form conks is unknown and needs to be tested in vivo. Because I. obliquus grows faster in Betula wood than Alnus, the use of Betula wood for producing inoculation dowels is recommended in order to shorten the production time. [ABSTRACT FROM AUTHOR]

Symbiotic relationships maintain the balance of forest ecosystems, with ectomycorrhizal (EcM) symbiosis being one of the most significant. EcM symbiosis in forests dominated by Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.) has been often observed, but remain understudied in parts of world. This study was conducted in the State Forest Natural Reserve "Ertis Ormany" in Kazakhstan. The aim of this study was to identify EcM symbionts on Scots pine and silver birch by analyzing ribosomal DNA sequences isolated from hyphal endings. Our results show that among all EcM symbionts the order Agaricales (13 species/28.8% of total species numer) had highest species diversity in Scots pine, followed by Boletales (9/20%) and Russulales (8/17.7 %). For silver birch, the order Russulales (7/15.5%) had highest species diversity, followed by Agaricales (5/11.1%), and Boletales (3/6.7%). A total of 15 symbiont families were identified: Agaricaceae (2 species/4,4% of the total number of species identified in the study area), Amanitaceae (4/8.9%), Boletacea (5/11.1%), Cortinariaceae (3/6.7%), Gloeophyllaceae (1/2.2%), Inocybaceae (1/2.2%), Lycoperdaceae (1/2.2%), Lyophyllaceae (2/4.4%), Paxillaceae (1/2.2%), Polyporaceae (3/6.7%), Psathyrellaceae (2/4.4%), Pseudoclitocybaceae (2/4.4%), Russulaceae (8/17.8%), Suillaceae (6/13.3%), and Tricholomataceae (4/8.9). A higher symbiotic association with EcM was found in Scots pine (66.5%) compared to silver birch (33.3%). [ABSTRACT FROM AUTHOR]

Fluctuating asymmetry is a sensitive indicator of favorable conditions during the period of individual development. The influence of climatic factors, biotopic conditions, latitude, altitude, and age of plants from the natural populations of the silver birch Betula pendula Roth was analyzed. The material consisted of 13,000 leaves of the silver birch from 11 regions of north-eastern Siberia. The influence of 23 climatic factors and six integrated coefficients characterizing the general suitability of the climate, as well as summer, winter, spring, and autumn was analyzed. The developmental stability of woody plants and, consequently, the level of the FA of the lamina in natural biotopes can vary in a wide range. We found that climatic factors, mainly conditions in the warm season, have a significant impact. We also noted the influence of the age, biotope, and light conditions. For Betula pendula, an increase in FA was registered on the ecological periphery of its range, i.e., on the edge of the forest belt in the north and in the mountains. The data obtained demonstrate the high influence of natural stress-inducing factors on development stability in plants. [ABSTRACT FROM AUTHOR]

Silver birch (Betula pendula Roth.) is an ecologically and economically important deciduous tree species in Northern Europe. In vitro culture initiation and shoot rejuvenation from birches in their reproductive phase is difficult and often unsuccessful. Currently, markers to evaluate the degree of juvenility of birch in vitro shoots, which could be used to track the rejuvenation process and to determine factors affecting it, have not been developed. The aims of this study were to assess expression of juvenility related microRNAs and target genes during micropropagation of silver birch, and to investigate factors affecting juvenility of birch genotypes with different in vitro morphogenic ability. Potential precursor sequences and target genes of the microRNAs miR156 and miR172 were determined by alignment to the birch unigene set. Ten potential miR156 and miR172 precursor sequences were identified, and were tested for the ability to form the required stem-loop structure. Based on precursor sequences, primers were designed for real time PCR analysis of precursor miRNA expression. Expression patterns of two miR156 family precursors (miR156_511 and miR156_789) and one miR172 precursor (miR172_1931) and two target genes (BpSPL1 and BpAP2) had the best correlation with juvenility/maturity in the analysed in vitro propagated silver birch samples. Expression patterns of these miRNA precursors and target genes were also investigated in samples cultured under different in vitro conditions. This study provides an initial survey of molecular markers for assessment of phase change in birch in vitro micropropagation. Key message: This study investigated expression of juvenility related micro RNAs and target genes in Betula pendula micropropagated material with differing juvenility and in vitro culture conditions. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the antibacterial activity of the aqueous and ethanolic extracts of Betula pendula (silver birch) bark against various microorganisms causing urinary tract infections.Material and methods. Aqueous and ethanol extracts of biologically active compounds from Betula pendula bark were tested against ten clinical uropathogenic strains (gram-positive bacteria — Kocuria rhizophila 1542, Staphylococcus simulans 5882, Enterococcus avium 1669, Enterococcus faecalis 5960, and Corynebacterium spp. 1638; gram-negative bacteria — Enterococcus cloacae, Morganella morganii 6392, Escherichia coli 1449, Seratia mansescens 6441, and Achromobacter xylosoxidans 4892). Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 25922 were used as reference standards for Gram-positive and Gram-negative microorganisms. The sensitivity of the experimental strains to the antibiotic was evaluated by the Kirby–Bauer disk diffusion method, while the antibacterial activity of the obtained extracts was evaluated using the agar diffusion method. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were also determined via the serial dilution method.Results. The bark of B.pendula contained 78.85% of dry matter. The volume yield of the aqueous (AE) and ethanol extract (EE) was 74.66% and 86.66% (v/v), respectively, while their mass yields were 6.59% and 10.65% (w/w). K.rizophilia 1542 and Corynebacterium spp. 1638 were the most resistant bacteria with a multidrug resistance index of 0.45. AE and EE were active against all microorganisms tested. MIC of AE ranged from 8 to 32 mg/ml, while MIC of EE ranged from 2 to 16 mg/ml.Conclusion. An aqueous extract of Betula pendula bark exhibits weak antimicrobial activity, while the ethanol extract exhibits a more pronounced antimicrobial activity, but has a bacteriostatic effect.

Mixed-species plantation forests are of high interest both because of their potentially superior productivity and multi-functionality benefits over monocultures. However, how trees of different species interact at the canopy level in mixed forests remains unclear, even at young growth stages. We tested whether crown shape and size and stand-level canopy packing were affected by stand composition and how mixture effects varied with stand density and irrigation. We measured crown attributes in pure and mixed plots of two light-demanding species, silver birch (Betula pendula Roth) and maritime pine (Pinus pinaster Ait.), in a 10-year-old tree diversity experiment (ORPHEE). This allowed us to estimate tree-level crown volumes and stand-level canopy packing. We found that (i) at the tree level, stand composition influenced crown-stem allometric relationships in pine but not in birch, (ii) mixture led to greater crown and tree dimensions in pine, but to the opposite for birch, (iii) the changes in crown volume resulted in a higher canopy packing in mixed stands, only at high density and with no irrigation, i.e., under highest constraints for light availability but also soil water availability, contrary to initial expectations. This study sheds light on the effects of water constraints on the aboveground mechanistic processes that explain greater productivity in young mixed plantations, and improves our understanding of canopy packing in mixed stands. [ABSTRACT FROM AUTHOR]

In this research, it was aimed to investigate (i) the recultivation efficiency, (ii) to assess the plantation state via a complex estimated indicator, and (iii) to evaluate the environmental quality in disturbed lands in a zone under influence of copper smelting production. The research was carried out on Golden Mountain, located in the influenced zone of the Karabashed Joint Stock Company. In three plantations as reclamation sites established by sowing and planting, silver birch (Betula pendula Roth), aspen (Populus tremula L.), balsam poplar (Populus balsamifera L.), goat willow (Salix caprea L.) as broadleaves, and Scots pine (Pinus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) as conifers were selected. Moreover, environmental quality was rated based on the condition scores by collecting leaf samples in four different sites of silver birch forests. As a result, the fluctuating activity method of the silver birch leaf blade seems to be effectively used to assess the environmental quality. At a considerable distance of 8.0 and 13.0 km from the pollution source, the environmental quality has an average [condition score: III with .046 integral asymmetry index] and initial level (condition score: II with .041 integral asymmetry index) of deviation from the norm, respectively. In addition, silver birch can be recommended as the main species in forestry on disturbed lands in the South Ural forest steppe region. [ABSTRACT FROM AUTHOR]

Mixed-species forests in Fennoscandia are of increasing interest because they may improve resilience, biodiversity, and productivity. Currently there is scarce knowledge available of the early growth dynamics of mixed spruce–birch stands in even-aged managed production forests with artificial regeneration of spruce. The main objective of our study was to examine the present state and the past growth dynamics of current single-storied, young spruce–birch (Picea abies (L.) Karst., Betula pendula Roth, Betula pubescens Ehrh.) stands (age 17–29 years), where spruce was planted and birch naturally regenerated, and juvenile management practices (early cleaning and precommercial thinning) were carried out. We inventoried ten such stands in Southern Finland, for a total of twenty plots. For 160 spruces and 160 birch trees, we reconstructed the past diameter and height growth through stem analysis. We analyzed mean stand characteristics by tree species, and we modelled the individual tree height and diameter growth using the mixed effects Chapman–Richards model. Spruces had slower initial height growth, but by the age of about 20 years their height growth rate eventually approached and exceeded that of birches regenerated naturally at the time of spruce planting. The diameter growth of planted spruce exceeded that of birches even sooner (at the age of about 10 years). Thus, spruces are not suppressed by birches, and they may coexist in the same canopy layer in managed stands. Contrary to earlier guidelines, due to the fast growth of planted spruces, birch mixture needs to be maintained already in the first juvenile stand management (i.e., early cleaning). The growth dynamics of young, planted spruce, and naturally regenerated birch allow the establishment and management of such mixtures and also maintenance of the mixture in the future until the end of the rotation, thus improving biodiversity in boreal, planted spruce forests. [ABSTRACT FROM AUTHOR]

The collection of birch sap in spring has become, in the past decades, a regular practice in Romania, because of its multiple health benefits. Over the years, many collectors experienced unsatisfactory results in terms of the amount of sap harvested, usually attributed to the unpredictable spring weather of some years, with large variations from a day to another. The results of this study revealed that independently of weather conditions in spring, the best period of sap harvesting in North-East of Romania was between 25th of March - 5th of April, when the air temperatures did not exceed 15°C. Trees higher than 20 m were most productive. At the end of the growing season, tapped trees were smaller than those untapped. These results suggest that in time, the tapped trees are less productive due to loss of vigour rather than spring weather conditions. [ABSTRACT FROM AUTHOR]

The aboveground parts of boreal forest trees grow earlier in the growing season, the roots mostly later. The idea was to examine whether root growth followed soil temperature, or whether shoot growth also demanded most resources in the early growing season (soil temperature vs internal sink strengths for resources). The linkage between air and soil temperature was broken by switching the soil temperature. We aimed here to identify the direct effects of different soil temperature patterns on physiology, leaf anatomy and their interactions, and how they relate to the control of the growth dynamics of silver birch (Betula pendula Roth). Sixteen 2-year-old seedlings were grown in a controlled environment for two 14-week simulated growing seasons (GS1, GS2). An 8-week dormancy period interposed the GSs. In GS2, soil temperature treatments were applied: constant 10 °C (Cool), constant 18 °C (Warm), early growing season at 10 °C switched to 18 °C later (Early Cool Late Warm) and 18 °C followed by 10 °C (Early Warm Late Cool) were applied during GS2. The switch from cool to warm enhanced the water status, net photosynthesis, chlorophyll content index, effective yield of photosystem II (Δ F / F m ′) and leaf expansion of the seedlings. Warm treatment increased the stomatal number per leaf. In contrast, soil cooling increased glandular trichomes. This investment in increasing the chemical defense potential may be associated with the decreased growth in cool soil. Non-structural carbohydrates were accumulated in leaves at a low soil temperature showing that growth was more hindered than net photosynthesis. Leaf anatomy differed between the first and second leaf flush of silver birch, which may promote tree fitness in the prevailing growing conditions. The interaction of birch structure and function changes with soil temperature, which can further reflect to ecosystem functioning. [ABSTRACT FROM AUTHOR]

Leaves are one of the vegetative organs of plants that are essential for plant growth and development. PIN-FORMED (PINs) gene is an indoleacetic acid (IAA) transporter that plays a critical role in leaf development. To determine the function of BpPIN3 in leaf polarity formation in Betula pendula, the transgenic lines with BpPIN3 overexpression (OE) and BpPIN3-reduced expression (RE) were analyzed using the Agrobacterium-mediated method. The RE lines displayed the characteristics of leaf margin adaxial upward curling, with lower expression of BpPIN3 resulting in greater rolling. Tissue localization of IAA in the auxin GUS reporter system proved that auxin in the RE was mainly distributed in the secondary veins, palisade tissues, and epidermal cells in the leaf margin area. The auxin content in the leaf margin area was significantly greater than that in the main vein tissue. The cell density of the palisade tissue and the ratio of palisade tissue to spongy tissue in the curled leaf margin of the RE lines were found to be significantly decreased. RNA-seq analysis revealed that the RE hormone-signaling pathway genes were significantly enriched compared with those of the OE and WT lines; in particular, the auxin response-related genes SAURs (i.e., SAUR23, SAUR24, SAUR28, and SAUR50) and GH3.10 were found to be significantly upregulated. qRT-PCR analysis indicated that BpPIN3 expression at the leaf margin was significantly lower than that near the main vein in the RE lines. In contrast, the expression levels of SAURs and GH3.10 were significantly higher than those near the midrib. In conclusion, BpPIN3 regulates the expression of auxin response-related genes and the polar transport of auxin to change the polar form of the proximal and distal axes of birch leaves. [ABSTRACT FROM AUTHOR]

The concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd, Pb and As heavy metals and the heavy metal accumulation levels of these plants were determined in Betula pendula and Populus tremula trees, which are the characteristic trees of Nemrut Crater Lake, the second largest crater lake in the world, and the soil samples surrounding them. Heavy metals are considered to be one of the most dangerous and priority pollutants due to their high persistence and toxicity to plant and animal life in the environment. For this reason, the results obtained will contribute to the studies carried out to determine the uptake of heavy metal pollutants in the environment and the selfhealing effort of the polluted environments by applying the phytoremediation method. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the current state of silver birch (Betula pendula Roth.) stands in Ukrainian Polissya, as well as to identify optimal composition resulting in productive and resilient mixed birch forests. It was found that in forests managed by the State Forest Resources Agency of Ukraine, birch stands grow on an area of 352 800 ha, covering 5.6% of the total area of forests in Ukraine. Within the study region of Ukrainian Polissya, birch stands cover 294 900 ha making 12.3% of the total forest area. Naturally originated birch stands were found to dominate in the study region, with 65.4% of vegetative stands and 25.2% of those grown from seeds. However, planted stands significantly prevail in terms of growing stock as compared to natural ones. In Ukrainian Polissya, silver birch trees grow as a part of mixed pine and birch forests on 632 400 ha. Our study found that mixed pine and birch stands with 80-90% of Scots pine and 20-10% of silver birch in the composition are the most productive. [ABSTRACT FROM AUTHOR]

Background. The tick-borne encephalitis virus (TBEV) is one of the most dangerous and epidemiologically significant vector-borne pathogens. There is a need for effective antiviral agents for the treatment and prevention of this infection. Previously we found that the mycelium of Inonotus rheades grown on birch wood contains water-soluble substances with strong virulicidal properties against TBEV. It is necessary to check whether the mycelium of I. rheades can synthesize virulicidal substances from wood of other species.The aim: to study the antiviral properties of extracts of I. rheades mycelium grown on coniferous wood, both in the presence and in the absence of blue light during cultivation.Materials and methods. The mycelium of I. rheades was grown on birch, pine, and fir wood. The direct virulicidal effect of the extract was evaluated by the decrease in the titer of the infectious virus incubated in the presence of the extract. The ability of the extract to inhibit the reproduction of the virus in infected cells was studied by the calculation of 50 % effective concentration (EC50). The toxicity of extracts for cells was evaluated based on the calculation of 50 % cytotoxic concentration.Results. Mycelium extracts grown on conifers under blue light do not cause a statistically significant decrease in the concentration of infectious TBEV (p = 0.2563). However, the BP10 extract (pine, blue light) inhibits TBEV reproduction in infected cells (EC50 = 0.28 ± 0.06 mg/mL). Toxicity for SPEV cell culture is low. In the extracts of conifers grown in the dark, no antiviral effect was found at all.Conclusions. The component composition and mechanism of the antiviral action of I. rheades extracts are determined by the species of the wood substrate. The most promising sources of new drugs in relation to TBEV appear to be extracts of I. rheades mycelium grown on birch and pine.

The number of invasive non-native pests is increasing rapidly in forests as a result of global change. It is therefore important to prevent their damage in order to preserve the integrity of forest ecosystems and the associated services. According to the biotic resistance hypothesis, species-rich communities are less likely to be invaded. The associational resistance hypothesis states that insect herbivores are more likely to colonise and exploit plants surrounded by conspecific neighbours than heterospecific, non-host plant species. More diverse forests would therefore be less damaged by non-native pests than tree monocultures. We tested these hypotheses by comparing the damage caused to seeds by the western conifer bug Leptoglossus occidentalis , an invasive insect native to North America, in plots of pure maritime pine and mixed plots of maritime pine and birch. These plots were in two tree diversity experiments in Europe. Mixed pine plots differed in terms of pine density (1250 versus 625 pines/ha), proportion of pine and birch (25 %, 50 %, 75 %) and spatial mixing pattern (aggregated versus dispersed). We sampled 635 cones in 37 plots. Overall, the proportion of seeds damaged by the invasive bug was significantly lower in mixed plots than in pure pine plots at both experimental sites. There was no significant effect of pine density or relative proportion in the mixtures on seed damage. Aggregated pines in the mixed plots were significantly more damaged than dispersed pines, suggesting that bugs may have done less damage when they had more difficulty locating their host trees. This is consistent with the hypothesis of lower plant apparency. These results support the view that forest plantations of mixed species, which are known to be less vulnerable to attack by native insects, may also be more resistant to infestation by exotic insects. Row-wise, intimate mixtures of two species represent a promising option for designing tree plantations that are more resistant and easier to manage. • The seed bug Leptoglossus occidentalis is invading coniferous forest in Europe. • Its damage to maritime pine is significantly lower in mixtures with birch. • Intimate mixing of pine with birch reduces damage even more. • The diversity of trees provides biotic resistance to plantations. [ABSTRACT FROM AUTHOR]

Plant polyploidization changes its leaf morphology and leaf development patterns. Understanding changes in leaf morphology and development patterns is a prerequisite and key to studying leaf development in polyploid plants. In this study, we quantified and analyzed the differences in leaf morphology, leaf growth polarity, and leaf size between diploid and tetraploid birches (Betula pendula subsp. pendula), and preliminarily investigated genes involved in leaf growth and development in birch. The results showed significant changes in leaf morphology in tetraploid birches, especially the basal part of the leaf. In addition, the proximal growth rate of tetraploid leaves was altered. The changed proximal growth rate did not affect the growth polarity pattern of tetraploid leaves. The leaf area of tetraploid was significantly larger than that of diploid birch. The difference in leaf size was mainly due to differences in their growth rates in the middle and late stages of leaf development. Increased cell expansion capacity was the major reason for the enormous leaves of tetraploid birch; however, cell proliferation did not contribute to the larger tetraploid leaf. The gene expression of ATHB12 was associated with cell size and leaf area, and may be a critical gene affecting the leaf size in diploid and tetraploid birches. The results will provide valuable insights into plant polyploid leaf development and a theoretical basis for later investigations into the molecular mechanisms underlying the gigantism of tetraploid birch leaves. [ABSTRACT FROM AUTHOR]