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Today, high amounts of residual nitrogen are regularly being reported in the open field production of hardy nursery stock. In some cases, excessive fertilizers or side-dressings are applied when circumstances are not favorable for uptake. Aquatic as well as terrestrial ecosystems are sensitive to enrichment with nutrients, but growers also benefit when losses are avoided. In this study, the potential of proximal optical sensors to optimize nitrogen fertilization was investigated in four woody species: Acer pseudoplatanus L., Ligustrum ovalifolium Hassk., Prunus laurocerasus ‘Rotundifolia’ L. and Tilia cordata Mill. For three consecutive growing seasons, plants were grown under three different fertilization levels to generate different nitrogen contents. Plant growth and nitrogen uptake were monitored regularly and combined with sensor measurements including Soil Plant Analysis Development (SPAD), Dualex and GreenSeeker. Here, we show that optical sensors at the leaf level have good potential for assisting growers in the sustainable management of their nursery fields, especially if leaf mass per area is included. Nevertheless, care should be taken when plants with different leaf characteristics (e.g., wax-layer, color, and leaf thickness) are measured. When all measuring years were considered, high correlations (R2 ≥ 0.80) were found between area-based foliar nitrogen content and its non-destructive proxy (i.e., chlorophyll)measured by Dualex or SPAD. Based on our results, we recommend a relative rather than absolute approach at the nursery level, as the number of species and cultivars produced is very diverse. Hence, knowledge of absolute threshold values is scarce. In this relative approach, a saturation index was calculated based on the sensor measurements of plants grown in a reference plot with an ample nitrogen supply.

The possibility of using a morpho-geometric method for determining the indices of the fluctuating asymmetry of Асеr pseudoplatanus L. leaf for bioindication is evaluated. The material was collected on the roadside territories of motorways in Donetsk City with different traffic intensity. The values of the fluctuating asymmetry of A. pseudoplatanus leaf blade, grown in conditions of city roadside ecosystems, are increased with the increase in the transport load, obtained through Procrustean analysis of variance. The morphogeometric method for determining the fluctuating asymmetry showed greater sensitivity in comparison with the use of an index calculated by the normalizing formula based on measurements of individual bilateral features. It is expedient to carry out studies in which the task is to accumulate data on the dynamics of fluctuating asymmetry indices obtained by a morphogeometric method, with a view to the subsequent widespread application of this approach for bioindication and biomonitoring of the state of the environment. [ABSTRACT FROM AUTHOR]

Changes are reported in perpendicular and parallel glossiness, lightness (L*), red colour (a*) tone, and yellow colour (b*) tone due to thermal aging in beech (Fagus orientalis Lipsky), maple (Acer pseudoplatanus L.), northern red oak (Quercus rubra), American black walnut (Juglans nigra L.), and walnut (Juglans regia L.) wood coated with a UV system commonly used on laminated parquets. Coated samples were exposed to different thermal aging levels (30 °C for 30 days, 60 °C for 60 days, and 90 °C for 90 days). Colour and gloss were determined before and after the thermal aging processes. The L* decreased for all species with the thermal aging decreasing more for more intense processes. Variations of the a* and b* colour parameters depended on the species. The colour parameters changed for temperatures higher than 30 °C. In general, glossiness decreased proportionally to the severity of the thermal aging for all of the species studied. [ABSTRACT FROM AUTHOR]

Hypoglycin A ( HGA) was detected in blood and urine of a horse suffering from atypical myopathy ( AM; Day 2, serum, 8290 μg/l; urine: Day 1, 574, Day 2, 742 μg/l) and in its cograzing partners with a high variability (46-1570 μg/l serum). Over the period of disease, the level of the toxic metabolites (methylencyclopropylacetic acid [ MCPA]-conjugates) increased in body fluids of the AM horse ( MCPA-carnitine: Day 2, 0.246, Day 3, 0.581 μmol/l serum; MCPA-carnitine: Day 2, 0.621, Day 3, 0.884 μmol/mmol creatinine in urine) and HGA decreased rapidly (Day 3, 2430 μg/l serum). In cograzing horses MCPA-conjugates were not detected. HGA in seeds ranged from 268 to 367 μg/g. Although HGA was present in body fluids of healthy cograzing horses, MCPA-conjugates were not detectable, in contrast to the AM horse. Therefore, increasing concentrations of MCPA-conjugates are supposed to be linked with the onset of AM and both parameters seem to indicate the clinical stage of disease. However, detection of HGA in body fluids of cograzing horses might be a promising step in preventing the disease. [ABSTRACT FROM AUTHOR]

The viability of desiccation-intolerant sycamore (Acer pseudoplatanus L.) seeds during desiccation was investigated by tetrazolium and by a germinability test, together with membrane permeability and membrane phospholipid composition. Loss of viability was associated with an increase of solute leakage, reduced content of all phospholipid groups, decrease of unsaturated fatty acids and the unsaturated/saturated fatty acids ratio. Growth of malondialdehyde content was also observed. Some results were compared with those for tolerant to desiccation Norway maple (Acer platanoides L.) seeds. The results indicate active participation of membranes in the desiccation process in tolerant seeds and their decomposition in intolerant ones. The destruction of membranes was the result of lipid peroxidation, probably due to the free radical effect.

Tree litter decomposition on disturbed post-mining sites has been mainly studied within successional gradients, whereas almost no results were shown from afforested spoil heaps. Litterfall and its decomposition rate are considered the most important ecological processes for soil restoration during stand development on such initial forest habitats. These processes allow development of a functional ecosystem and productive forest stands. Moreover, the pedogenesis process on such “soilless”’ habitats can be significantly improved and accelerated by tree species selection during afforestation. The main aim of the study was to determine litter decomposition rates of nine tree species used for afforestation of a lignite mine spoil heap. We assumed that leaf litter decomposition rates would differ among tree species studied and that the site conditions would significantly influence this process. Our study was conducted on the spoil heap of the lignite open cast mine in Bełchatów, central Poland. We studied leaf litter decomposition of Alnus glutinosa , Betula pendula , Pinus sylvestris , Quercus robur , Q. rubra and Robinia pseudoacacia in pure stands of these species (home stands), and litter decomposition of Acer pseudoplatanus , A. glutinosa , Fagus sylvatica , Prunus serotina , Q. rubra , and R. pseudoacacia in Scots pine stands. We used the litterbag method. The experiments lasted for three years and the samples were collected every three months. Leaf litter decomposition calculated for home stands after three years of decomposition was 94.4% of the initial leaf mass for A. glutinosa , 70.9% for R. pseudoacacia , 70.1% for P. sylvestris , 68.3% for B. pendula , 66.9% for Q. rubra and 61.5% for Q. robur . In Scots pine stands, after three years of the experiment, 92.3% of the initial leaf mass decomposed for P. serotina , 85.7% for A. glutinosa , 83.5% for A. pseudoplatanus , 65.2% for R. pseudoacacia , 50.9% for Q. rubra and 40.1% for F. sylvatica . A. glutinosa , R. pseudoacacia and Q. rubra leaves decomposed significantly faster in home stands than in Scots pine stands. Site aspect significantly influenced litter decomposition of the species studied, with higher rates mostly on the western slope. Our study revealed that the decision on tree species used for afforestation might shorten the period needed for soil restoration and achievement of sustainability of novel ecosystems. Proper selection of main and admixture tree species for afforestation of the post-mining sites might reduce the renewal period of the soilless and newly created habitats, which may provide noticeable ecological and economical effects during stand management. [ABSTRACT FROM AUTHOR]

Research on urban climates has been an important topic in recent years, given the growing number of city inhabitants and significant influences of climate on health. Nevertheless, far less research has focused on the impacts of light pollution, not only on humans, but also on plants and animals in the landscape. This paper reports a study measuring the intensity of light pollution and its impact on the autumn phenological phases of tree species in the town of Zvolen (Slovakia). The research was carried out at two housing estates and in the central part of the town in the period 2013-2016. The intensity of ambient nocturnal light at 18 measurement points was greater under cloudy weather than in clear weather conditions. Comparison with the ecological standard for Slovakia showed that average night light values in the town centre and in the housing estate with an older type of public lighting, exceeded the threshold value by 5 lux. Two tree species, sycamore maple (Acer pseudoplatanus L.) and staghorn sumac (Rhus typhina L.), demonstrated sensitivity to light pollution. The average onset of the autumn phenophases in the crown parts situated next to the light sources was delayed by 13 to 22 days, and their duration was prolonged by 6 to 9 days. There are three major results: (i) the effects of light pollution on organisms in the urban environment are documented; (ii) the results provide support for a theoretical and practical basis for better urban planning policies to mitigate light pollution effects on organisms; and (iii) some limits of the use of plant phenology as a bioindicator of climate change are presented. [ABSTRACT FROM AUTHOR]

For the first time a pedoanthracological study was undertaken in the Black Forest, SW Germany, considering forest soils in the highest altitudes of this region. For this purpose a total of ten soil profiles were studied in the Southern Black Forest, namely each two parallel profiles in high altitudes of five summit areas. Our pedoanthracological approach includes extraction and taxonomic analysis of soil charcoal fragments as well as quantification of soil charcoal concentration. The main aims of our investigation were the verification of significant charcoal residues and their distribution and concentration within the soil on different spatial scales, as well as the taxonomic analysis of single charcoal pieces. In total, 37 g charcoal were extracted from the soil samples, which yielded 2240 charcoal fragments suitable for taxonomic analysis. Most pieces of charcoal have been established of maple ( Acer ), followed by fir ( Abies ) and spruce ( Picea ). Only 31 charcoal pieces of beech ( Fagus ) were found, which represent 1.8 % of total extracted charcoal. The four tree taxa mentioned are the most common one of the potential natural vegetation (mature forests). Species of these taxa continue to be important components in the study areas. Today norway spruce ( Picea abies ) is dominating in the upper montane belt of the Southern Black Forest by far, followed by beech ( Fagus sylvatica ), while silver fir ( Abies alba ) is rare. Currently sycamore maple ( Acer pseudoplatanus ) is frequently found in the upper montane belt, but usually with proportions of less than 10 %. The pedoanthracological results of the five study sites indicate an increase in Picea -share geographically from west to east as well as orographically with increasing altitude. Charcoal concentrations of the magnitudes established suggest that for the most part the soil charcoal found is the result of natural forest fires. [ABSTRACT FROM AUTHOR]

Whereas improved tree mineral nutrition is known to be one driver behind the higher growth in mixed vs pure stands, the effects of stand density and admixture of species with limited functional dissimilarity remain very poorly documented. Our study therefore addresses the impact of local neighbourhood, including density and species composition, on tree nutrition for two species with a limited contrast in traits. We investigated foliar nutrition in a young mixed plantation of beech ( Fagus sylvatica L.) and sycamore maple ( Acer pseudoplatanus L.), planted along a double gradient of density and species proportion. Target trees of both species were selected over the full diameter range along this double gradient, and neighbourhood (local density, species identity and diversity) was determined in a 3 m radius. Using standardized regression analysis, we investigated direct effects of tree size and neighbourhood, and indirect effects of neighbourhood through tree size. Mostly we observed positive tree size effects in both species, be it stronger in beech. For maple, direct positive species identity effects were observed for C, N, P, S, K, Mg, Mn, Zn and Al. For beech, we found indirect negative effects of stand density and diversity. These results were in general agreement with growth data, which suggests that nutrition is one of the driving factors behind complementarity in this stand. We conclude that at this stage the effect of tree size dominates over the neighbourhood effects, including density and diversity. However, the presence of beech reduced intraspecific competition in maple with a positive effect on the foliar nutrient content. As neighbourhood effects are expected to increase as the plantation matures, our findings highlight the potential of admixing tree species with limited dissimilarity in traits for practical use in forestry. [ABSTRACT FROM AUTHOR]

Sooty bark disease ( SBD) caused by the pathogen Cryptostroma corticale is currently one of the risks to the population of Acer pseudoplatanus in Europe. After a number of records of symptomatic and dead trees in Prague, assessment of the latent non-symptomatic stage of SBD was questioned as a means to forecast the health risk of the A. pseudoplatanus population. We used two methods of early detection of C. corticale in non-symptomatic trees: cultivation from wood tissue on agar plates and a culture-free approach based on nested PCR with newly designed species-specific primers. The pathogen was detected in 25% of 112 examined trees from seven localities in Prague, but the disease incidence might be higher if more A. pseudoplatanus trees in Prague were included and if the crown infections were considered. The presence of C. corticale was positively correlated with discoloured wood, but its presence did not depend on the occurrence of external symptoms. Infected trees were more frequently found in groups on steep sites at higher elevations. In addition, heavier NOx pollution combined with more paths and roads increased the incidence of C. corticale. [ABSTRACT FROM AUTHOR]

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The aim of the study was to assess the effects of different forest stands (Silver fir (Abies alba) and sycamore maple (Acer pseudoplatanus) with common hornbeam (Carpinus betulus)) on the enzymes activities and microbial biomass. The objective was to explore how changes in the detritus inputs affect soil organic matter (SOM) composition. The content of SOM fraction has been compared with soil enzyme activities. The investigation was carried out in the Świętokrzyskie Mountains of central Poland. Twenty investigation plots were selected, including fir stands (10 plots) and maple with hornbeam stands (10 plots). Contents of organic C, N and base cations, pH, hydrolytic acidity, and soil texture were investigated. The content of C and N in the physically separated SOM fractions was distinguished. The study indicated only small changes in soil properties and stabilization of organic matter as a result of different detritus inputs. The maple-hornbeam and fir stands have a similar influence on microbiological processes and the SOM. Acidity of soil is a major factor affecting microbial activity and therefore pH affects enzyme dynamics. Differences in soil pH confirmed the stronger acidifying effects of fir stands compared to maple-hornbeam stands. Additionally, fir stands stimulate β-glucosidase activity, probably through a simultaneous interaction of mycorrhizal fungi in the roots of fir stands. [ABSTRACT FROM PUBLISHER]

The knowledge of the rate at which trees grow in urban areas is an important aspect to consider as it can influence our quantification and valuation of the ecosystem services provided by an urban forest. This study investigates growth variations in diameter and height for four common urban tree species ( Acer pseudoplatanus , Betula pendula , Fraxinus excelsior and Quercus robur ) across five cities in Great Britain (GB) and how the typical radial growth of two of those species ( F. excelsior and Q. robur ) changes with climate. Dendrochronology was used to identify tree age and changes in ring width and diameter at breast height (DBH) and tree height were measured in-situ at the time of coring. Results indicate a substantial variation in the mean annual growth rates and the relationships between DBH and age or height and age of each species across different cities. However, the multiple factors affecting tree growth seem to influence different species in different ways, with for example A. pseudoplatanus trees showing overall the fastest growth in Peterborough but B. pendula ones showing the slowest. Precipitation and temperature had an effect on radial growth of F. excelsior and Q. robur trees in GB, but the strength and direction of influence varied with time of year, species and city. In particular, low precipitation at the start or during the growing season was found to be a significant factor limiting radial growth. A trend towards a reduction in ring width increment was therefore identified in hot and dry years, primarily in south-eastern cities but in other cities too. This highlights the risk that a changing climate may have on the growth and, consequently, on the ecosystem service provision of healthy urban trees. [ABSTRACT FROM AUTHOR]

• Abundance of advance regeneration of four broadleaved species in a primary beech forest. • Replacement of canopy trees by F. sylvatica occurs irrespective of canopy neighbourhood. • Proximity to dead lying trees and gaps is crucial for Acer spp. and U. glabra recruitment. • Acer spp. poles can replace F. sylvatica hosts but mainly those growing in gaps. • The number of F. sylvatica poles is the same as Acer spp. even in the largest gap (>2000 m2). Tree replacement patterns strongly shape species coexistence and dominance in forest ecosystems. In mixed forests subject to a small-scale disturbance regime, dead canopy trees are often replaced by advance regeneration. We studied the abundance of saplings (6–10 cm dbh) and poles (10–25 cm dbh) under canopy trees based on four inventories on a 10-ha permanent plot in a large primary forest dominated by Fagus sylvatica in Ukraine. Saplings and poles of Fagus sylvatica, Acer platanoides, A. pseudoplatanus and Ulmus glabra were spatially linked to canopy trees ('hosts', dbh > 25 cm) based on their crown radius, and the hosts' neighborhood was classified according to the presence of dead trees. The number of saplings and poles under hosts was modelled with a Bayesian approach. There was a higher number of advance regeneration under hosts with increasing host diameter. The abundance of advance regeneration was the lowest under hosts in the canopy (i.e., under shaded conditions) and highest for hosts growing in gaps. 1) Under the canopy, only F. sylvatica poles can replace heterospecific hosts > 80 cm dbh, while other pole species are clearly below the replacement threshold. 2) Near dead lying trees, Acer pseudoplatanus rarely achieved an abundance of one pole at a host dbh > 80 cm. 3) In gaps, Acer spp. poles were able to replace F. sylvatica hosts. The proximity to dead lying trees and gaps is crucial for Acer spp. and U. glabra saplings for recruitment to the pole stage. The higher rate of recruitment under hosts adjacent to dead lying trees suggests that the total length of gap edges may be as important as gap size or disturbance frequency. In gaps > 550 m2, advance regeneration without hosts (growing in gaps) of Acer spp. can recruit higher number of saplings than F. sylvatica, but not poles. We conclude that almost all canopy trees of Acer spp. and U. glabra are likely to be replaced by Fagus sylvatica if the current small-scale disturbance regime and single-tree mortality continue to prevail. [ABSTRACT FROM AUTHOR]

Cryptostroma corticale was observed on declining trees of Acer pseudoplatanus L. at Montovolo, a mountain site located in the northern Apennines, Italy. Morphological and biomolecular analyses confirmed the presence of the fungus in affected trees, which has not yet been officially described as occurring in Italy. No damage by the pathogen was observed on other species of Acer in the affected area, while drought–related decline symptoms were present on Quercus pubescens and Ostrya carpinifolia near the affected site, confirming the possible role of climate and especially repeated drought periods in the appearance of the problem.

Field studies were conducted in the years 2003 - 2005 in the Rymanów Forest Unit in 13 stands aged between 40 to 100 years, which had 10% - 60% of the sycamore in their species composition. They grew on a mountain forest site (12 stands) and mountain riparian forest (1 stand). In each of them 100 trees were examined, growing next to each other in the central part of the stands. The disease symptoms, on trunks and in the crown area of each tree, and their intensity were determined according to the predefined symptomatic - developmental code. More than 80 fragments of wood and bark were collected from trunks of living and dead trees with local cankers and bark peeling off exposing wood. From the samples, 798 isolations were made on 2% malt - agar medium. The examined sycamores in the Rymanów Forest Unit showed a large variation in the disease symptoms and their occurrence frequency. Among 1300 analyzed trees, only 13.7% did not show external, macroscopic disease symptoms. There was a relatively large share of dead trees (15.0%), which in individual stands ranged 4.0 - 32.0%. The most frequent symptoms in crowns were as follows: top dying (6.3% trees), entire branch dying (16.2%) or only their tops (9.6%), crown thinning (19.4%), leaf atrophy (10.8%) and leaf discoloration (11.6%). On sycamores trunks, the following symptoms were found: plate-like and strip-like necrosis of bark that was breaking, falling off and exposing wood (8.6% trees), local bark cankers (14.7%), among which healed ones dominated (10.3%), bark cracks (14.3%) and tree cancer symptoms (3.8%). Bark necrosis and wood exposure formed 1.5 times more frequently on the northern and western side than on the southern and eastern side, bark cracks appeared most frequently on the southern trunk side. On the cross sections of sycamore trunks, the following symptoms were found predominantly: T-shaped discolorations which appeared in the place of local healed cankers, dead wood regions in the places of local unhealed cankers and widespread bark cankers, sometimes taking the form of a sector reaching the part near the pith, and greyish - green or greenish - brown wood discolorations in the form of numerous stains, especially in the trunk periphery part. On the trunks of 184 (14.2%) sycamores, perithecia of Nectria coccinea were present. They formed in the area of cankers on bark and exposed wood alike. Fruiting bodies of Nectria cinnabarina, Eutypa acharii, Melanomma pulvis-pyrius, conidiomata of Cytospora ambiens, Aposphaeria cf. pulviscula and conidiomata of Stegonsporium pyriforme occurred sporadically. From wood, the following were isolated predominantly: Basidiomycetes sp. 1, Chalara sp. 1, Cadophora fastigiata, Nectria cinnabarina and Cytospora ambiens. Chalara sp.1, with its morphological features, best matched the anamorph of Ceratocystis coerulescens sensu lato.

The presence of symplasmic isolation and symplasmic continuity which are functional aspects of cell-to-cell communication, had been studied in cambium of Acer pseudoplatanus and Ulmus minor, with hope that uniqueness of this meristem, exemplified by its morphology and seasonal variations in its activity is also manifested in differences in the efficiency of communication between cambial cells during the year. The degree of symplasmic continuity was estimated by loading the fluorescent symplasmic tracer to the stem and following its distribution in a population of cambial cells observed on tangential, transverse and radial sections. In active cambium the tracer did not enter the rays. This suggested that the ray and fusiform cells, growing and dividing intensively at different rates were specifically isolated from each other. In the state of dormancy the tracer was present also in the rays implying continuity between the two types of cambial cells. Temporal restriction in tracer spreading from secondary xylem to cambial region was observed on transverse sections in both physiological states of the meristem. Higher degree of symplasmic isolation in active cambium is, most probably, associated with functional distinctiveness of ray and fusiform cells. We hypothesize further that the symplasmic continuity in dormant cambium results from the open conformation states of plasmodesmata, because the energy costs of these states are low. It is reasonable strategy when cambial cells do not divide and maintenance of their functional individuality is not necessary.

This paper examines and discusses the specific belt sanding resistance K (N·cm-2) and specific belt sanding intensity SI (g·cm-2·min-1), for wood of Pinus sylvestris L., Picea abies L., Quercus robra L., Acer pseudoplatanus L., Alnus glutinosa Gaertn., and Populus Nigra L., by different sanding pressure pS, different sanding grit NG number, and different wood grain angles Phi(v).

Wooded pastures are semi-natural ecosystems that are often considered biodiversity hotspots and are valuable for nature conservation. Ongoing land-use changes, such as management intensification, threaten these ecosystems. Several studies have assessed the effect of tree density and cover on plant species richness, but the individual effects of single trees have not been addressed previously. We studied the effects of single sycamore maple trees ( Acer pseudoplatanus ) in sycamore maple wooded pastures on vascular plant and ground bryophyte species richness at six sites in the northern European Alps. In total, we found 346 vascular plant species and 264 bryophyte species. Alpha- and beta-diversity were positively influenced by the trees and positively related to tree size- and tree age-related variables. The positive effect of the trees on the species richness of epigeic bryophytes was reduced at high levels of management intensity, possibly due to severe disturbance by cattle trampling under the trees. However, our data showed that the diversity of the ground vegetation increased when trees were present, even in intensively managed pastures. Our findings highlight the high species richness present in sycamore maple wooded pastures at different spatial scales. The trees in sycamore maple wooded pastures can thus be considered keystone structures providing a range of important functions and conservation policies should particularly emphasize the conservation of large and old trees as well as the planting of young trees in these ecosystems. [ABSTRACT FROM AUTHOR]

Temperate forests are expected to be particularly vulnerable to drought and soil drying because they are not adapted to such conditions and perform best in mesic environments. Here we ask (i) how sensitively four common temperate tree species (Fagus sylvatica, Picea abies, Acer pseudoplatanus and Fraxinus excelsior) respond in their water relations to summer soil drying and seek to determine (ii) if species-specific responses to summer soil drying are related to the onset of declining water status across the four species. Throughout 2012 and 2013 we determined tree water deficit (TWD) as a proxy for tree water status from recorded stem radius changes and monitored sap flow rates with sensors on 16 mature trees studied in the field at Lägeren, Switzerland. All tree species responded equally in their relative maximum TWD to the onset of declining soil moisture. This implies that the water supply of all tree species was affected by declining soil moisture and that none of the four species was able to fully maintain its water status, e.g., by access to alternative water sources in the soil. In contrast we found strong and highly species-specific responses of sap flow to declining soil moisture with the strongest decline in P. abies (92%), followed by F. sylvatica (53%) and A. pseudoplatanus (48%). F. excelsior did not significantly reduce sap flow. We hypothesize the species-specific responses in sap flow to declining soil moisture that occur despite a simultaneous increase in relative TWD in all species reflect how fast these species approach critical levels of their water status, which is most likely influenced by species-specific traits determining the hydraulic properties of the species tree. [ABSTRACT FROM AUTHOR]

Climate conditions in cities are constantly changing, creating a worsening environment for the growth of trees and performing their ecological functions. Qualitative evaluation of their responses to the often extreme climatic conditions and habitat for their growth is an important part of care for urban and historical greenery. This work deals with applying visual methods for the assessment of morphological characters, crown destructive manifestations and eco-physiological aspects of vitality through micromarker of quality of assimilation organs. Evaluation was carried out in two types of environment, in city of Nitra and an environmentally unloaded historical park in Nová Ves nad Žitavou. The research was conducted on six trees of species Acer pseudoplatanus L., through visual assessment and measuring the values of chlorophyll fluorescence-a. The measurement results were statistically evaluated and graphically interpreted. [ABSTRACT FROM AUTHOR]

Carbon (C) storage is considered a key component to plant survival under drought and shade, although the combined effects of these factors on survival remain poorly understood. We investigated how drought and shade alter the C dynamics and survival of tree seedlings, and whether drought limits the access to or usage of stored C. We experimentally applied two levels of soil humidity (wellwatered versus drought, the latter induced by dry-down) and light availability (light versus complete darkness) on 1-year-old seedlings of Acer pseudoplatanus L. for 3 months. We quantified the survival, biomass, growth rate and non-structural carbohydrates (NSC) of seedlings at their time of death or at the end of the experiment for those that survived. We found that the soil dried out faster when drought was combined with light than when it was combined with complete darkness. Seedlings subjected to both drought and light showed reduced growth and reached 100%mortality earlier than any other treatment, with the highest NSC concentrations at the time of death. Seedlings exposed to both drought and complete darkness died significantly earlier than seedlings exposed to complete darkness only, but had similar NSC concentrations at time of their death, suggesting that drought accelerated the use of stored C under complete darkness. Complete darkness significantly reduced seedling growth and whole-plant NSC concentrations regardless of soil humidity, while root NSC concentrations were significantly more reduced when complete darkness was combined with drought conditions. Thus, the C dynamics in A. pseudoplatanus seedlings under complete darkness was not hindered by drought, i.e., the access and use of stored C was not limited by drought. The contrasting growth and C storage responses driven by drought under light versus complete darkness are consistent with a key role of the drought progression in the C dynamics of trees. [ABSTRACT FROM AUTHOR]

Eutypella canker of maple, caused by Eutypella parasitica (which is native to North America), is reported for the first time from Germany. From 2013 to 2015, this perennial canker disease was recorded on 105 maple trees in Munich. Six maple species were affected: Acer pseudoplatanus, A. campestre, A. platanoides, A. cappadocicum, A. heldreichii ssp . trautvetteri and A. hyrcanum. Occurrence on the latter three species represents new host records for E. parasitica. In Austria, Eutypella canker was newly discovered on two trees at a second locality in 2011, and it is now known to occur on seven A. pseudoplatanus trees at two localities, which are separated nearly 150 km. A. pseudoplatanus was the most frequent host of E. parasitica in Munich and Austria, which is in agreement with previous studies in Europe. The identity of the causative pathogen as E. parasitica was verified by ITS rDNA sequencing of fungal cultures obtained from cankers in Munich and at both Austrian localities. The presence of large and old cankers in both countries suggests that introduction of E. parasitica dates back a long time, probably several decades. The new records of Eutypella canker in Germany and Austria show that the disease is more widely distributed in central Europe than previously recognized. [ABSTRACT FROM AUTHOR]

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees ( Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes. [ABSTRACT FROM AUTHOR]

Aside quantity, the value of the timber is in tight correlation with its quality as well. The quality of the timber, in living trees, is directly influenced by the site factors, but some attributes are genetically fixed. This proves the importance of genetics and tree breeding in the improvement of the timber quality. By form defects of standing trees it is understood the overcoming of certain limits, established through standards of certain morphometical attributes of the trunk. The importance of defects depends on the wood material's given destination as well. [ABSTRACT FROM AUTHOR]

By comparison with other ecosystem types, the forest describes itself as a high complexity and diversity, resilience, stability and an uncontested ecological, social and economic efficiency. Between all these characteristics of the forest there is a tight bond, and the higher the biodiversity is, the stronger its stability and resilience will be to the harmful biotic and abiotic factors. Real life examples are known, from the literature, where many stands were affected by harmful factors, like strong winds and great amounts of snow. The vast majority of these stands are pure, meaning they contained only one species, like beech or spruce. Although the pure stands are easier to manage from the silvotechnic point of view, those presents more risks than the mixed stands, where numerous species also have the mutual protection role. [ABSTRACT FROM AUTHOR]

Elevated sulphur dioxide (SO 2 ) concentrations were the major cause of the absence of symptoms of tar spot ( Rhytisma acerinum ) of sycamore ( Acer pseudoplatanus ), in urban areas in the 1970s. The subsequent large decline in SO 2 concentrations has not always been accompanied by increased tar spot symptoms, for reasons that have remained unresolved. We used a large citizen science survey, providing over 1000 records across England, to test two competing hypotheses proposed in earlier studies. We were able to demonstrate the validity of both hypotheses; tar spot symptoms were reduced where there were fewer fallen leaves as a source of inoculum, and elevated nitrogen dioxide concentrations reduced tar spot symptoms above a threshold concentration of about 20 μg m −3 . Symptom severity was also lower at sites with higher temperature and lower rainfall. Our findings demonstrate the power of citizen science to resolve competing hypotheses about the impacts of air pollution and other environmental drivers. [ABSTRACT FROM AUTHOR]