Acer Pseudoplatanus Research Articles

Integration of MsrB1 and MsrB2 in the Redox Network during the Development of Orthodox and Recalcitrant Acer Seeds.

Two related tree species, Norway maple (Acer platanoides L.) and sycamore (Acer pseudoplatanus L.), produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. We compared the seeds of these two species to characterize the developmentally driven changes in the levels of peptide-bound methionine sulfoxide (MetO) and the abundance of methionine sulfoxide reductases (Msrs) B1 and B2, with respect to the cellular redox environment. Protein oxidation at the Met level was dynamic only in Norway maple seeds, and the reduced MsrB2 form was detected only in this species. Cell redox status, characterized by the levels of reduced and oxidized ascorbate, glutathione, and nicotinamide adenine dinucleotide (NAD)/phosphate (NADP), was clearly more reduced in the Norway maple seeds than in the sycamore seeds. Clear correlations between MetO levels, changes in water content and redox status were reported in orthodox Acer seeds. The abundance of Msrs was correlated in both species with redox determinants, mainly ascorbate and glutathione. Our data suggest that MsrB2 is associated with the acquisition of desiccation tolerance and that ascorbate might be involved in the redox pathway enabling the regeneration of Msr via intermediates that are not known yet.

Аналіз життєвості вуличних насаджень після омолоджувальної обрізки (на прикладі м. Дніпро)

The influence of pruning of the crown on the state of five tree species has been studied (Robinia pseudoacacia L., Ulmus pumila L., Gleditsia triacanthos L., Acer pseudoplatanus L. and Populus bolleana Lauch.). The trees were pruning at a height of 8 meters, leaving only the trunk and lower branches. Control plants were not pruned. All plants are growing on the boulevard near the highway with high traffic. It was found that among the rejuvenated trees there are more both healthy plants and severely damaged ones. Dead plants appeared among species such as G. triacanthos, A. pseudoplatanus, and R. pseudoacacia also. The best vital state was found in P. bolleana and U. pumila. Plants after crowning have more water content in leaves. U. pumila and G. triacanthos have the greatest difference in water content between the two variants. The intensity of transpiration in pruning plants P. bolleana and G. triacanthos is 2 times higher, and in U. pumila – by 20 %. In A. pseudoplatanus and R. pseudoacacia, there is no difference in this indicator between the variants. Pruned plants have a lower water-holding capacity by an average of 30 % compared to control (except for P. bolleana, in which the difference between the variants is insignificant). The content of green pigments is higher than in the control samples in the leaves of the rejuvenated plants. The exception is R. pseudoacacia, which has a reverse reaction. Thus, the intensification of the processes of water exchange and the pigment system does not occur in all species to the same extent. It is most pronounced in U. pumila and G. triacanthos. The activity of photosynthesis and water exchange in both variants differs insignificantly at P. bolleana. R. pseudoacacia have deterioration in all parameters. This probably explains the poor condition of pruned trees of this species.

Moderate effects of tree species identity on soil microbial communities and soil chemical properties in a common garden experiment

Knowledge about the effects of tree species on soil physicochemical and microbial properties is crucial for sustainable forest management. The evaluation of these effects in common garden experiments may be advantageous compared to natural conditions due to the reduction of confounding factors such as differences in topography, microclimate, the age of the tree stand, the admixture of other tree species or soil type. In this study, we assessed the effects of 14 tree species grown for nearly 50 years in monospecific plots in the Siemianice Experimental Forest in Poland on soil microbial community assessed by phospholipid fatty acid (PLFA) analysis, namely total, bacterial (G+, G−) and fungal biomass, fungi/bacteria ratio, G+/G− ratio, and microbial community structure, as well as on soil chemical properties, namely pH, organic C, total Ca, K, Mg, N, P, exchangeable Ca, K, Mg, N-NH4, N-NO3, S-SO4, and C/N ratio. Species richness (species number) and cover of undergrowth vegetation were also assessed. We found only moderate effects of tree species identity on soil. Significant differences were found in fungal biomass, fungi/bacteria ratio, and microbial community structure, with the highest fungal biomass under Betula pendula and Quercus rubra. Among chemical parameters, significant differences were observed in soil pH and base cations concentrations. The highest values of these parameters were under Acer pseudoplatanus, A. platanoides, and Tilia cordata. Total microbial, bacterial (G−), fungal biomass, and fungi/bacteria ratio were significantly higher under broadleaf than under coniferous species, while for G+/G− ratio the opposite was observed. Tree species with arbuscular mycorrhiza did not generally differ in their effects on soil microbial biomass from those with ectomycorrhiza. Total microbial and G+ bacterial biomass correlated positively with soil elements, mainly base cations, C, and N, while very few correlations were found between soil chemical properties and G− bacteria and fungi. Species richness and cover of undergrowth vegetation were not related to any of soil microbial properties. The lack of correlations between soil element contents, undergrowth vegetation, and some microbial groups may suggest that these microorganisms are primarily influenced by other soil/litter properties, for example secondary metabolite concentrations.

Development of Root Architecture in Thirty-seven Tree Species of Field Grown Nursery Stock1

AbstractThe number and size of lateral roots of a tree seedling can be evaluated visually, and could potentially be used to select plants with better root systems early in nursery production. To evaluate how root architecture develops in young trees, root architecture of 37 species of trees was compared at two stages of development: as harvested seedlings, and then one year after replanting. The total number of lateral roots and the number of roots >2mm (0.08 in) diameter that were present on the portion of the taproot remaining on seedlings after standard root pruning were recorded. Neither could consistently predict the number of lateral roots on the root system one year after replanting. Development of roots (sum of diameters) regenerated from the cut end of the seedling taproot was equal or greater than lateral root development in 84 percent of evaluated species. Even when regenerated root development was significantly less than lateral root development, the regenerated roots still comprised up to 44 percent of the root system. Regenerated roots from the cut end of the taproot can become a major component of the architecture of the structural root system in nursery stock.Index words: structural roots, nursery production, root regeneration.Species used in this study: European black alder (Alnus glutinosa Gaertn.), green ash (Fraxinus pennsylvanica Marshall), quaking aspen (Populus tremuloides Michx.), European white birch. (Betula pendula Roth), river birch (Betula nigra L.), black locust (Robinia pseudoacacia L.), northern catalpa (Catalpa speciosa (Warder) Warder ex Engelm.), Mazzard cherry [Prunus avium [L.) L.], chokecherry (Prunus virginiana L.), American elm (Ulmus americana L.), Siberian elm (Ulmus pumilia L.), goldenchain tree (Laburnum anagyroides Medik.), northern hackberry (Celtis occidentalis L.), Cockspur hawthorn (Crateagus crus-galli L.), single seed hawthorn (Crateagus monogyna Jacq.), honeylocust (Gleditsia tricanthos L.), Japanese pagodatree [Sophora japonica (L.) Schott], Katsura tree (Cercidiphyllum japonicum Siebold & Zucc.), Kentucky coffee tree [Gymnocladus dioicus (L.) K. Koch], littleleaf linden (Tilia cordata Mill.), boxelder (Acer negundo L.), hedge maple (Acer campestre L.), Norway maple (Acer platanoides L.), red maple (Acer rubrum L.), silver maple (Acer saccharinum L.), sugar maple (Acer saccharum Marshall), sycamore maple (Acer pseudoplatanus L.), English Oak (Quercus robur L.), northern red oak (Quercus rubra L.), Siberian peashrub (Caragana arborescens Lam.), American plum (Prunus Americana Marshall ), Myrobalan plum (Prunus cerasifera Ehrh.), redbud (Cercis Canadensis L.), Russian olive (Elaeagnus angustifoliaI L.), tuliptree (Liriodendron tulipifera L.), black walnut (Juglans nigra L.), Japanese zelkova (Zelkova serrata (Thunb.) Makino).

Effect of the wood anisotropy on eigenmodes and eigenvalues using finite element analysis – case of violin plates

The paper presents numerical studies performed with FEA related to the effect of wood anisotropy on vibration modes of violin plates made of spruce (Picea abies) and maple (Acer pseudoplatanus). The two-wood species are the traditional species for the top and back of the violins. In this study, three hypotheses – the material is isotropic; the material is transverse isotropic; the material is orthotropic, was used for modal analysis of violin plates. The plates were considered flat and having uniform thickness of 3 mm. Patterns obtained with modal analysis of violin vibration plates are illustrated for low frequencies modes and were compared to experimental results. The effect of anisotropy was illustrated by the variation of modal frequency of plates with the frequency of resonance modes. The difference between modal frequencies for the modes 6, 9, 10 and 12, calculated for the plate made of spruce and for the plate made of maple having orthotropic symmetry is respectively between 1.38% and 7%. For isotropic symmetry and for the same modes, this difference for the plate made of spruce and maple varies respectively between 57% and 18.92 %. The effect of anisotropy on the modal frequency of plate made of maple is more important than that on plate made of spruce.

Effects of drought on nitrogen uptake and carbon dynamics in trees.

Research on drought impact on tree functioning is focussed primarily on water and carbon (C) dynamics. Changes in nutrient uptake might also affect tree performance under drought and there is a need to explore underlying mechanisms. We investigated effects of drought on (a) in situ nitrogen (N) uptake, accounting for both, N availability to fine roots in soil and actual N uptake, (b) physiological N uptake capacity of roots and (c) the availability of new assimilates to fine roots influencing the N uptake capacity using 15N and 13C labelling. We assessed saplings of six different tree species (Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl., Abies alba Mill., Picea abies (L.) H.Karst. and Pinus sylvestris L.). Drought resulted in significant reduction of in situ soil N uptake in deciduous trees accompanied by reduced C allocation to roots and by a reduction in root biomass available for N uptake. Although physiological root N uptake capacity was not affected by drought in deciduous saplings, reduced maximum ammonium but not nitrate uptake was observed for A. alba and P. abies. Our results indicate that drought has species-specific effects on N uptake. Even water limitations of only 5weeks as assessed here can decrease whole-plant inorganic N uptake, independent of whether the physiological N uptake capacity is affected or not.

Short-term survival and crown rebuilding of European broadleaf tree species following a severe ice storm

Ice storms cause widespread damage to forests in many temperate regions, leaving behind many live trees with severe crown damage. Following a severe ice storm in 2014 that damaged forests across Slovenia, we examined how tree-level attributes influenced survival and crown rebuilding three growing seasons after the storm. Field sampling was carried out in four mature stands dominated by native broadleaf species. Of the 763 sampled trees, the annual mortality rate following the storm was 2.2%, and nearly all trees that died experienced >75% crown removal. Oak (Quercus petraea (Matt.) Liebl.) and chestnut (Castanea sativa Mill.) had higher rates of mortality than beech (Fagus sylvatica L.) and maple (Acer pseudoplatanus L.). Mixed models revealed that survival significantly increased with tree diameter and decreased with increasing crown damage. Although we observed sprouting across all the dominant species, maple, oak, and chestnut showed a more vigorous response than beech, and maple had the fastest sprout growth. Model results showed that sprout density and length increased with level of crown damage. The results indicate that these broadleaf forests are resilient to severe ice damage. Consequently, hasty salvage cutting of trees with canopy damage should be avoided, as many individuals with >75% crown damage are likely to survive and recover.

Long-term tree species population dynamics in Swiss forest reserves influenced by forest structure and climate

Changes in tree species composition can have strong effects on ecosystem functioning and the services provided by forests. Empirical observations can provide an improved understanding of the drivers of species population dynamics, yet long-term datasets are scarce in natural forests. This study used inventory data of the Swiss forest reserve network to assess tree population dynamics over the past 60 years. Tree status, species and dbh were repeatedly measured between 1956 and 2018 in 211 permanent plots of 34 forest reserves that covered a wide environmental gradient. Differences in species richness and tree density were compared between the first and last inventory. Furthermore, we used generalized linear mixed effect models to estimate the processes of ingrowth and tree mortality of seven abundant species (Abies alba, Acer pseudoplatanus, Fagus sylvatica, Fraxinus excelsior, Picea abies, Pinus sylvestris and Quercus spp.) separately as a function of stand structural attributes and climate. We found a general decline in the density of the dominant species, with a low recruitment of light-demanding species and an increase in species richness, particularly in the colline vegetation zone. Both species-specific ingrowth and tree mortality were influenced by stand density and climate variables. Tree mortality increased with live tree density and increasing temperature. Ingrowth increased with tree density and decreased with higher temperature. Therefore, forest structural properties and climate have a strong influence on species population dynamics, and both are essential for predicting ingrowth and tree mortality in forest ecosystems.

Plant-mycorrhiza association in urban forests: Effects of the degree of urbanisation and forest size on the performance of sycamore (Acer pseudoplatanus) saplings

Environmental change as result of urbanisation can influence soil microbial communities in green areas. In cities, forests are among the most frequent types of green areas and provide a wide variety of ecosystem services for the residents, such as air cleaning, nutrient cycling and area for recreational activities. Mycorrhizal fungi play an important role for the establishment of trees and therefore for the natural regeneration of forests. We examined the effect of urbanisation on the arbuscular mycorrhizal (AM) fungal symbiosis and performance of Acer pseudoplatanus saplings in a controlled field experiment in forests situated in the city of Basel and its suburbs in Switzerland. A total of 660 one-year-old A. pseudoplatanus saplings were planted in plots in 11 forests, which differed in degree of urbanisation in the surroundings and size. Saplings including their full root systems were harvested after 4, 6 and 13 months. AM fungal colonisation was 15–45 % lower on roots of saplings growing in forests located in areas with a high degree of urbanisation than that on sapling roots in forests in less urbanised areas. Furthermore, AM fungal colonisation of saplings decreased with decreasing forest size. Sapling survival was not influenced by urbanisation, but by forest size. In particular, sapling survival was reduced in small and medium-sized forests. Sapling survival also increased with increasing percentage of AM fungal colonisation after 13 months. These urbanisation- and forest-size induced changes became more pronounced with the time elapsed since the saplings were planted. Our findings demonstrate the negative impact of urbanisation on AM fungal symbiosis and the performance of A. pseudoplatanus saplings and indicate that urbanisation is a threat for the long-term maintenance of intact small urban forests.

UAS Imagery-Based Mapping of Coarse Wood Debris in a Natural Deciduous Forest in Central Germany (Hainich National Park)

Dead wood such as coarse dead wood debris (CWD) is an important component in natural forests since it increases the diversity of plants, fungi, and animals. It serves as habitat, provides nutrients and is conducive to forest regeneration, ecosystem stabilization and soil protection. In commercially operated forests, dead wood is often unwanted as it can act as an originator of calamities. Accordingly, efficient CWD monitoring approaches are needed. However, due to the small size of CWD objects satellite data-based approaches cannot be used to gather the needed information and conventional ground-based methods are expensive. Unmanned aerial systems (UAS) are becoming increasingly important in the forestry sector since structural and spectral features of forest stands can be extracted from the high geometric resolution data they produce. As such, they have great potential in supporting regular forest monitoring and inventory. Consequently, the potential of UAS imagery to map CWD is investigated in this study. The study area is located in the center of the Hainich National Park (HNP) in the federal state of Thuringia, Germany. The HNP features natural and unmanaged forest comprising deciduous tree species such as Fagus sylvatica (beech), Fraxinus excelsior (ash), Acer pseudoplatanus (sycamore maple), and Carpinus betulus (hornbeam). The flight campaign was controlled from the Hainich eddy covariance flux tower located at the Eastern edge of the test site. Red-green-blue (RGB) image data were captured in March 2019 during leaf-off conditions using off-the-shelf hardware. Agisoft Metashape Pro was used for the delineation of a three-dimensional (3D) point cloud, which formed the basis for creating a canopy-free RGB orthomosaic and mapping CWD. As heavily decomposed CWD hardly stands out from the ground due to its low height, it might not be detectable by means of 3D geometric information. For this reason, solely RGB data were used for the classification of CWD. The mapping task was accomplished using a line extraction approach developed within the object-based image analysis (OBIA) software eCognition. The achieved CWD detection accuracy can compete with results of studies utilizing high-density airborne light detection and ranging (LiDAR)-based point clouds. Out of 180 CWD objects, 135 objects were successfully delineated while 76 false alarms occurred. Although the developed OBIA approach only utilizes spectral information, it is important to understand that the 3D information extracted from our UAS data is a key requirement for successful CWD mapping as it provides the foundation for the canopy-free orthomosaic created in an earlier step. We conclude that UAS imagery is an alternative to laser data in particular if rapid update and quick response is required. We conclude that UAS imagery is an alternative to laser data for CWD mapping, especially when a rapid response and quick reaction, e.g., after a storm event, is required.

In Vitro Interactions between Eutypella parasitica and Some Frequently Isolated Fungi from the Wood of the Dead Branches of Young Sycamore Maple (Acer pseudoplatanus)

The ten most frequently isolated fungi from the wood of the dead branches of Acer pseudoplatanus L. were tested in dual cultures to evaluate their in vitro antagonistic activity against Eutypella parasitica R.W. Davidson and R.C. Lorenz, the causative agent of a destructive disease of maples in Europe and North America. The tested fungi, treated also as challenge isolates, were Diaporthe sp., Eutypa sp., Eu. maura, E. parasitica, Fusarium avenaceum, Neocucurbitaria acerina, Neonectria sp., Peniophora incarnata, Petrakia irregularis, and Phomopsis pustulata. The antagonistic ability of each challenge isolate was evaluated by calculating an index of antagonism (AI) based on the interaction type in the dual cultures. The results of competition between the fungal isolates were quantified after re-isolations from the interaction zone (s). The dual cultures revealed two main types of competitive interactions: Deadlock, consisting of mutual inhibition after mycelial contact or at a distance, and replacement, reflecting in the inhibition of E. parasitica, followed by partial overgrowth by the replacing fungus. Statistical analysis showed significant differences in average AI and s of challenge isolates between different dual culture assays. Based on the results of the antagonism index, Eutypa sp., Eu. maura, Neonectria sp., and P. incarnata had the highest inhibitory effect on E. parasitica growth and were recognized as the most promising candidates for further biocontrol studies of E. parasitica. The mycelium of E. parasitica at the interaction zones remained mostly viable, except in dual cultures with Eutypa sp., F. avenaceum, and Neonectria sp., where re-isolations did not yield any colony of the E. parasitica isolate. Based on the results, we assume that E. parasitica is a weak competitor, which invests less energy in direct mycelial competition. We discuss the potential of the observed antagonists as a possible biocontrol of Eutypella canker of maple. Nevertheless, additional experiments should be performed for a solid conclusion about competitive ability of E. parasitica and usefulness of antagonists as biocontrol.

On the state of the ground cover of shaded areas in urban landscaping objects

It has been established that in municipal forestry of Stavropol (streets, squares, boulevards, parks) mixed plantations of broad-leaved tree species Tilia cordata Mill., Acer pseudoplatanus L., A. platanoides L., Aesculus hippocastanum L., Fraxinus excelsior L., Quercus robur L., prevail, which increases the shading conditions for lawns arranged under their canopy. With sparse and single-row planting of trees, lawn grass is in conditions of temporary shading and does not significantly suffer (lawns of good and satisfactory quality). In places with multi-row and group placement of tree plantations, the grass of lawns is in conditions of both temporary and permanent shading and is thinned up to 40–60 %, the relative amount of sunlight (RAS) is 2.1–9.2 % (mediocre and poor lawns). In conditions of constant intensive shading with a RAS of 0.6–2.6 %, turf grasses completely fall out, a dead cover forms, which reduces the quality of greening. Usually sparse grass are sown with fast-growing turf grasses annually. The issue of turfing of the shaded areas of parks with local forest grasses Brachypodium sylvaticum (Huds.) P. Beauv., Dactylis polygama Horvat., Festuca gigantea (L.) Vill., Poa nemoralis L. (RAS 2.1–5.8 %) and sedge Carex divulsa Stokes, (RAS 1.0–4.2 %) and the conservation of forest herbaceous cenoses is discussed. In shady parks, the use of ground cover introduced species Vinca minor L., Hedera helix L, and the herbaceous perennial Helleborus caucasicus A. Braun (RAS 1.2–7.4 %) is promising.

Horse-chestnut leafminer Cameraria ohridella: invasion history and prognosis

This work summarizes all known data on the distributive history of Cameraria ohridella in Europe and in Russia with special reference to current process of invasion to different regions of Russia and prognosis on its future spread through Russian territories. The invasion of the pest started in 1980s and to the present time Cameraria ohridella had occupied the most part of Europe. During last ten years from 2010 to 2020, Cameraria ohridella occupied 11 oblasts of the European Russia and was discovered in Kyrgyzstan and Kazakhstan. The main host trees of the pest are trees from the genus Aesculus. However, in the focus locations of invasion, the pest damages other trees growing near chestnuts. The data on biology of Cameraria ohridella showing that its larvae as a rule perish within the first two instars in case of development for example on Acer pseudoplatanus trees, give us confidence that the distributive range of the pest is restricted to the area of chestnut and locations of its decorative use.

Functional and ecosystem service differences between tree species: implications for tree species replacement

Tree species differ in their functioning at the scale of an individual tree which will result in differences in ecosystem service provision. Replacement trees for diseased trees should take account of functional differences. Globally tree species composition is changing due to species loss from pests and pathogens. The impact of this change on ecological functioning is rarely tested. Using six sites across the UK, with multiple tree species at each site, we test for functional differences between three species threatened by disease in the UK: Quercus petraea, Q. robur and Fraxinus excelsior and six other species: Acer pseudoplatanus, Castanea sativa, Fagus sylvatica, Quercus cerris, Quercus rubra, and Tilia x europaea, which have previously been suggested as ecological replacements. Differences between species were detected for all the variables measured: nitrogen mineralization, decomposition rate, total soil carbon and nitrogen, soil pH, soil temperature, and bark water holding capacity. Non-native Quercus species were only suitable replacements for native Quercus for some of the functions measured but replicating native Quercus functioning using a mixture of other species may be possible. The functioning of F. excelsior was different from most other tree species, suggesting that replicating its functioning with replacement tree species is difficult. The work highlighted that which species replaces diseased trees, even at the scale of single trees, will impact on the functions and ecosystem services provided.

A phytoplasma survey reveals the presence of ‘CandidatusPhytoplasma fragariae’ inUlmusspp. andAcer pseudoplatanusin Belgium

AbstractA Belgium‐wide survey to determine the presence of ‘CandidatusPhytoplasma ulmi’ elm trees was performed on nearly 600 elm trees. The randomly sampled elms were screened for the presence of phytoplasmas using a standard generic nested PCR method. In five symptomless elm trees, phytoplasmas were detected. Multiple gene sequence analysis (16S rRNA, tuf, rplV‐rpsC‐rplP), virtual RFLP of the 16S rRNA gene fragment and phylogenetic analysis showed that the phytoplasma strains detected in all five elm trees could be classified into the 16SrXII‐E subgroup (‘CandidatusPhytoplasma fragariae’‐related phytoplasma). In addition, a maple tree (Acer pseudoplatanus) located in close proximity to one of these elm trees was also determined to be infected with ‘Ca. P. fragariae’.UlmusandAcerare new host plant genera for this phytoplasma. Further studies are needed to elucidate the epidemiological impact of these findings.

Spontaneous forest communities of introduced species in Kryvyi Rih area

The article is devoted to the study of woody plants communities, that spontaneously form in the abandoned areas of Kryvyi Rih Area as a result of spontaneous-invasive settling of species in previously established plantations. For the study, we laid 16 trial plots in 5 growth sites of such communities. We determined the species composition and biometric characteristics of primary woody plants and those, that formed these communities due to the invasion. In the first such community, which was formed due to the settling of other species in a 40-year-old plantation of Salix alba L., we found on 3 plots with an area of 625 m2 94 medium-sized trees Acer negundo L. having height (h) 11.8–13.6 m, trunk diameter (D) 16.8–17.3 cm and crown projection area (S) 9.5–10.4 m2, as well as 210 young generative trees, their height varies between 6.5–7.3 m, trunk diameter 5.0–5.4 cm, and the projection of the crown 2.5–6.3 m2. In this community also grow young and medium-generative trees of Robinia pseudoacacia L. – respectively 7 individuals – h = 7.2–11.7 m, D = 8.1–10.7 cm, S = 6.1–6.5 m2 and 7 ones – h = 13.5–14.0 m, D = 18.1–27.0 cm, S = 14.0–38.5 m2. Among self-seeding plants, such species predominate: Acer platanoides L. – 3905 specimens and Acer negundo – 1823 specimens. Three species dominate in the three dense forestation massive near the highway, which occupy an area of 250 m2: Robinia pseudoacacia, Ulmus pumila L., Fraxinus excelsior L. and Cerasus avium (L.) Moench. Robinia pseudoacacia is the most common among medium-generative plants, and Acer negundo, A. platanoides, A. tataricum L. – among young generative plants. Self-seeding of Robinia pseudoacacia, Acer platanoides, Fraxinus excelsior and Acer negundo is dominated in this area. In the abandoned Ulmus pumila plantation near the iron ore mine in three areas with an area of 625 m2, 12 to 33 specimens of medium-generative trees of this species with a height of 12.2–13.1 m with a trunk diameter of 14.7–16.0 cm and a crown projection of 25, 5–27.3 m2. Its self-seeding is quite active in all areas. Self-seeding plants of Acer negundo are also present here – 51 specimens and Acer platanoides – 35 ones. Self-seeding plants of A. platanoides – 9837 specimens, A. pseudoplatanus – 2111 specimens, Ailanthus altissima (Mill.) Swingle – 396 specimens dominate in the neglected park on the territory of 500 m2, where Acer pseudoplatanus, Acer platanoides, Robinia pseudoacacia grow. A study was also carried out on the example of the Zelena gully in order to determine how invasive species spontaneously penetrate into the formed steppe feathergrass-fescue phytocenoses. In the upper part of the Zelena gully, located outside of Kryvyi Rih, more than 40 years ago, forest belts were created from many species of shrubs, which have already been listed. Crataegus fallacina Klokov and Rhamnus cathartica L. diffusely inhabit and clearly predominate in the 6 trial plots that were laid on the slopes of the south-eastern and north-western exposures. In the presence of a large number of seed donors from the previously mentioned species on the slopes of the gully firstly Crataegus fallacina settles. Morphometric parameters of shrubs of these species were slightly larger on the north-western slope than on the south-eastern: the height of Crataegus fallacina – 2.5–2.9 m, and the diameter of the crown – 3.5–4.3 m, while in Rhamnus cathartica – the height of the bush was 0.7–0.8 m, and the diameter of the crown – 0.5–1.1 m. Thus, invasive species of Ulmus pumila, Acer negundo, Robinia pseudoacacia and Ailanthus altissima, which are the main in spontaneous communities in abandoned anthropogenically disturbed areas of the city, do not penetrate into stable phytocenoses. Most of these species of woody plants show low invasive activity and do not form multispecies communities in weakly disturbed feather-fescue phytocenoses.

Equine atypical myopathy: consumption of sycamore maple seedlings (Acer pseudoplatanus) by pastured horses is driven by seedling maturity and might be associated with phenolic compounds.

Poisoning with Acer pseudoplatanus L. in horses contradicts the hypothesis of coexistence between plants and vertebrate herbivores being mediated through antipastoral traits as toxins. However, incidental observations showed that horses evaded Acer seedlings with primary leaves. The objective of the present cross-discipline study was (i) to analyse whether developmental stages of A. pseudoplatanus L. differed as to phenolics hypothesised as antipastoral traits, and (ii) to observe systematically the selection behaviour of pastured horses towards A. pseudoplatanus seedlings. Phenolic profiles of five developmental stages from fruits to seedlings of progressing age up to adult leaves of A. pseudoplatanus and Acer campestre L. were characterised. Video recordings of grazing behaviour of 29 pastured horses towards seedlings of A. pseudoplatanus resulted into 117 sequences as additional field data. The horses ingested 19.1 per cent of juvenile seedlings with cotyledons (1.65 mg total phenolics/g fresh weight (FW), 82 compounds, 0.02 mg total gallic acid/g FW) yet only 5.46 per cent of older seedlings with primary leaves (8.48 mg total phenolics/g FW, 120 compounds, 3.13 mg total gallic acid/g FW). Horses distinguished between seedlings in distinct stages that could be chemically distinguished, too. Acer seedlings with primary leaves provide a strong, but not complete antipastoral effect that correlates with dramatic changes in phenolic compounds.

Strength grading of hardwoods using transversal ultrasound

Detection of local wood inhomogeneities is important for accurate strength and stiffness prediction. In hardwood specimens, visual characteristics (e.g. knots or fibre deviation) are difficult to detect, either with a visual surface inspection or by the machine. Transversal ultrasound scan (TUS) is a non-destructive evaluation method with high potential for hardwoods. The method relies on differences in ultrasound wave propagation in perpendicular to the grain direction. The aim of this study is to estimate and analyse the capabilities of TUS for defect detection in hardwoods and prediction of mechanical property values. In the current paper, the TUS was applied to the hardwood species European ash (Fraxinus excelsior L.), Norway maple (Acer platanoides L.) and sycamore maple (Acer pseudoplatanus L.). In total, 16 boards of both specimens were completely scanned perpendicular to the grain using a laboratory scanner with dry-coupled transducers. The measurements were processed to 2D scan images of the boards, and image processing routines were applied to further feature extraction, defect detection and grading criteria calculation. In addition, as a reference for each board, all relevant visual characteristics and mechanical properties from the tensile test were measured. Using the TUS global fibre deviation, the size and the position of the knots can be detected. Knottiness correlates to the strength properties similarly or even better compared to the manual knottiness measurement. Between the global fibre angle measured using TUS and measured on the failure pattern, no correlation could be found. The ultrasound modulus of elasticity perpendicular to the grain does not show any meaningful correlation to the elastic properties parallel to the grain. In overall, TUS shows high potential for the strength grading of hardwoods.

Arsenic uptake, speciation and physiological response of tree species (Acer pseudoplatanus, Betula pendula and Quercus robur) treated with dimethylarsinic acid

The aim of the study was to evaluate the effect of dimethylarsinic acid (DMA) on growth parameters and levels of stress-related metabolites in Acer pseudoplatanus, Betula pendula and Quercus robur. The increase of DMA concentration in the solution led to a notable growth retardation of trees. An intense As accumulation (mainly As(III) and As(V)) expressed as BCF and TF > 1 was recorded only for Q. robur. Generally a decrease in contents of cellulose, hemicellulose and holocellulose with a simultaneous increase in lignin content were recorded. Phenolic composition of leaf extracts was modified by DMA, while root and rhizosphere extracts were poor in phenolics. Toxicity of DMA leads to a significant drop in salicylic acid content in leaves observed at lower doses. Higher DMA levels caused a second, probably ROS-derived depletion of the metabolite accompanied with a severe growth retardation, most pronounced in the case of B. pendula. DMA caused the inhibition of LMWOA biosynthesis in roots of A. pseudoplatanus, B. pendula and their exudation into the rhizosphere, while in Q. robur roots and leaves a stimulation of their accumulation was observed. Disturbances in the activity of enzymatic antioxidants were observed for all the species following the increasing level of DMA.

Canopy Position Has a Stronger Effect than Tree Species Identity on Phyllosphere Bacterial Diversity in a Floodplain Hardwood Forest

The phyllosphere is a challenging microbial habitat in which microorganisms can flourish on organic carbon released by plant leaves but are also exposed to harsh environmental conditions. Here, we assessed the relative importance of canopy position—top, mid, and bottom at a height between 31 and 20 m—and tree species identity for shaping the phyllosphere microbiome in a floodplain hardwood forest. Leaf material was sampled from three tree species—maple (Acer pseudoplatanus L.), oak (Quercus robur L.), and linden (Tilia cordata MILL.)—at the Leipzig canopy crane facility (Germany). Estimated bacterial species richness (Chao1) and bacterial abundances approximated by quantitative PCR of 16S rRNA genes exhibited clear vertical trends with a strong increase from the top to the mid and bottom position of the canopy. Thirty operational taxonomic units (OTUs) formed the core microbiome, which accounted for 77% of all sequence reads. These core OTUs showed contrasting trends in their vertical distribution within the canopy, pointing to different ecological preferences and tolerance to presumably more extreme conditions at the top position of the canopy. Co-occurrence analysis revealed distinct tree species-specific OTU networks, and 55–57% of the OTUs were unique to each tree species. Overall, the phyllosphere microbiome harbored surprisingly high fractions of Actinobacteria of up to 66%. Our results clearly demonstrate strong effects of the position in the canopy on phyllosphere bacterial communities in a floodplain hardwood forest and—in contrast to other temperate or tropical forests—a strong predominance of Actinobacteria.