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Using hierarchical clustering with unweighted pair-group method with arithmetic mean (UPGMA) we arranged 602 phytosociological releves of beech forests on the present forest line, mainly from the Julian Alps and the Trnovo Forest Plateau (we also included the releves from the Karawanks and the Kamnik Alps) into 32 clusters. Based on their analysis and comparison with previously described similar (alti)montane-subalpine beech communities we classified most of the releves into the association Polysticho lonchitis-Fagetum and its new subassociations ericetosum carneae, cardaminetosum trifoliae, luzuletosum niveae, luzuletosum luzuloidis, calamagrostieteosum variae, allietosum victorialis, adoxetosum moschatellinae, stellarietosum nemorum and several new variants. The altitude of the studied stands is predominantly 1400 to 1550 m (the upper line is at 1660 m); they occur at all aspects, frequently on steep and very steep slopes, mainly on limestone and dolomite limestone, the predominant soil type is rendzina. These stands are species rich (on average 61 species per releve, altogether more than 500 vascular plants) and have many species in common with the stands of associations Rhododendro hirsuti-Fagetum and Rhodothamno-Laricetum. They belong to the habitat type of Community interest 91K0 Illyrian Fagus sylvatica forests and are some of the best preserved forest communities in the Southeastern Alps and northwestern Dinaric Alps, comprising small areas of virgin forest remnants and performing an important protective role as a biotope.

Ectomycorrhizal plants trade plant-assimilated carbon for soil nutrients with their fungal partners. The underlying mechanisms, however, are not fully understood. Here we investigate the exchange of carbon for nitrogen in the ectomycorrhizal symbiosis of Fagus sylvatica across different spatial scales from the root system to the cellular level. We provided 15N-labelled nitrogen to mycorrhizal hyphae associated with one half of the root system of young beech trees, while exposing plants to a 13CO2 atmosphere. We analysed the short-term distribution of 13C and 15N in the root system with isotope-ratio mass spectrometry, and at the cellular scale within a mycorrhizal root tip with nanoscale secondary ion mass spectrometry (NanoSIMS). At the root system scale, plants did not allocate more 13C to root parts that received more 15N. Nanoscale secondary ion mass spectrometry imaging, however, revealed a highly heterogenous, and spatially significantly correlated distribution of 13C and 15N at the cellular scale. Our results indicate that, on a coarse scale, plants do not allocate a larger proportion of photoassimilated C to root parts associated with N-delivering ectomycorrhizal fungi. Within the ectomycorrhizal tissue, however, recently plant-assimilated C and fungus-delivered N were spatially strongly coupled. Here, NanoSIMS visualisation provides an initial insight into the regulation of ectomycorrhizal C and N exchange at the microscale.

The Žumberak and Samobor highlands are situated in the north-western part of Croatia where the characteristics of the Dinarides, the Alps and the Pannonian Plain meet. The greater part of the area is occupied by beech forests. The aim of the study was to determine the syntaxonomic affiliation of these forest communities, and to explore their floristic and main ecological features. Numerical analyses of floristic compositions were conducted on a data-set consisting of 144 new relevés and 99 relevés from the existing literature. Relevés were made following the standard Braun-Blanquet method. For descriptions of ecological conditions Ellenberg’s indicator values were used. Six plant associations and two subassociations of beech forests were established in Luzulo-Fagion and Aremonio-Fagion alliances. The higher altitudes of the studied area are occupied by ass. Cardamini savensi-Fagetum, whereas the lower altitudes are occupied by ass. Lamio orvalae-Fagetum and Hacquetio-Fagetum. Ass. Hacquetio-Fagetum spreads on southern slopes and ridges, whereas ass. Lamio orvalae-Fagetum occurs in ditches and on northern slopes. In the warmer habitats with shallow soils on a dolomite base ass. Ostryo-Fagetum occurred. A small part of the area is characterized by silicate substrate which is occupied by ass. Luzulo-Fagetum and Gentiano asclepiadeae-Fagetum.

Mycorrhizal fungi play an important role for the nitrogen (N) supply of trees. The influence of different mycorrhizal types on N acquisition in tree–tree interactions is, however, not well understood, particularly with regard to the competition for growth-limiting N. We studied the effect of competition between temperate forest tree species on their inorganic and organic N acquisition in relation to their mycorrhizal type (i.e., arbuscular mycorrhiza or ectomycorrhiza). In a field experiment, we quantified net N uptake capacity from inorganic and organic N sources using 15N/13C stable isotopes for arbuscular mycorrhizal tree species (i.e., Acer pseudoplatanus L., Fraxinus excelsior L., and Prunus avium L.) as well as ectomycorrhizal tree species (i.e., Carpinus betulus L., Fagus sylvatica L., and Tilia platyphyllos Scop.). All species were grown in intra- and interspecific competition (i.e., monoculture or mixture). Our results showed that N sources were not used complementarily depending on a species’ mycorrhizal association, but their uptake rather depended on the competitor, indicating species-specific effects. Generally, ammonium was preferred over glutamine and glutamine over nitrate. In conclusion, our findings suggest that the inorganic and organic N acquisition of the studied temperate tree species is less regulated by mycorrhizal association but rather by the availability of specific N sources in the soil as well as the competitive environment of different tree species.

[Motivation] Trait variation within species can reveal plastic and/or genetic responses to environmental gradients, and may indicate where local adaptation has occurred. Here, we present a dataset of rangewide variation in leaf traits from seven of the most ecologically and economically important tree species in Europe. Sample collection and trait assessment are embedded in the GenTree project (EU-Horizon 2020), which aims at characterizing the genetic and phenotypic variability of forest tree species to optimize the management and sustainable use of forest genetic resources. Our dataset captures substantial intra- and interspecific leaf phenotypic variability, and provides valuable information for studying the relationship between ecosystem functioning and trait variability of individuals, and the response and resilience of species to environmental changes., [Main types of variable contained] We chose morphological and chemical characters linked to trade-offs between acquisition and conservation of resources and water use, namely specific leaf area, leaf size, carbon and nitrogen content and their ratio, and the isotopic signature of stable isotope 13C and 15N in leaves., [Spatial location and grain] We surveyed between 18 and 22 populations per species, 141 in total, across Europe., [Time period] Leaf sampling took place between 2016 and 2017., [Major taxa and level of measurement] We sampled at least 25 individuals in each population, 3,569 trees in total, and measured traits in 35,755 leaves from seven European tree species, i.e. the conifers Picea abies, Pinus pinaster and Pinus sylvestris, and the broadleaves Betula pendula, Fagus sylvatica, Populus nigra and Quercus petraea., [Software format] The data files are in ASCII text, tab delimited, not compressed., All authors acknowledge support from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement no. 676876 (Project GenTree). Laboratory work was also supported by other projects: COMEDIAS (CGL2017- 83170-R, Spanish Ministry of Science, Innovation and Universities), REMEDINAL IV (TE-CM S2018/EMT-4338, Project of the Autonomous Community of Madrid, Spain), SPONFOREST (BIODIVERSA-3, PCIN-2016-055), and International Laboratory of Global Change (LINCGlobal 4540-143AP). The Swiss contribution was supported by the Swiss Secretariat for Education, Research and Innovation (SERI) under contract no. 6.0032. BC was funded by a Scholarship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES (Brazil).

Inspection of green stands in order to identify representatives of the genus Phyllonorycter Hübner, 1822 (Lepidoptera: Gracillariidae, Lithocolletinae), which damage woody plants in Belarus, revealed a new species for the fauna – beech midget (Phyllonorycter maestingella (Müller, 1764)). In 2014 we discovered this new invasive insect pest of the beeches (Fagus spp.) in Belarus for the first time. During 2014–2018 leaf mines of Ph. maestingella were recorded in 2 localities, Minsk and Brest, on 3 hostplant species, Fagus sylvatica Linnaeus, 1753, Fagus grandifolia Ehrhart, 1788, and Fagus orientalis Lipsky (1898). It is important to note that American beech (F. grandifolia) is recorded as a new host plant for Ph. maestingella. A list of points of registrations is given. This species of Lithocolletinae is alien to the fauna, since all representatives of the genus Fagus L. are introduced into Belarus.

The saprotrophic, endophytic, and parasitic fungi were detected from the samples collected in the forest of the management unit East Psunj and Papuk Nature Park in Croatia. The disease symptoms, the morphology of fruiting bodies and fungal culture, and DNA barcoding were combined for determining the fungi at the genus or species level. DNA barcoding is a standardized and automated identification of species based on recognition of highly variable DNA sequences. DNA barcoding has a wide application in the diagnostic purpose of fungi in biological specimens. DNA samples for DNA barcoding were isolated from infected tree tissues, fungal fruiting bodies or fungal cultures. The ITS or ITS2 sequences of the fungal DNA were sequenced and aligned with the reference sequences in GenBank (NCBI) using BLAST. The size of ITS and ITS2 sequences were 512-584 bp and 248-326 bp, respectively. The sequences showed a high identity of 97.21%-100% at 98%-100% coverage with reference sequences in GenBank (NCBI). The exception was the species Amphilogia gyrosa that showed 95.65% identity at 100% coverage. Two fungi were determined at genus level: Cladosporium sp., and Cytospora sp., while 11 fungi were determined at species level: Alternaria alternata, Aureobasidium pullulans, Amphilogia gyrosa, Capronia pilosella, Cryphonectria parasitica, Exidia glandulosa, Epicoccum nigrum, Penicillium glabrum, Pezicula carpinea, Rosellinia corticium, and Stereum hirsutum.

Sperry’s packing rule predicts the optimum packing of xylem conduits in woody plants, where the frequency of xylem conduits varies approximately inversely with the square of the conduit radius. However, it is well established that such anatomical disposition does not remain fixed but is subject to a suite of adaptations induced by physiological constraints driven by both ontogenetic development and environmental characteristics. Here we challenge the hypothesis that increasing frequency of xylem conduits, concomitant with the decrease in their lumen area along the xylem pathway, would affect the spatial distribution of vessels inside tree-rings and their aggregation. To this end, we measured the vessels’ anatomical characteristics inside each tree-ring along with a complete radial series taken at different stem heights of Fagus sylvatica L. trees. Point pattern analysis indicated a significant effect of the distance from the tree base and a weak effect of cambial age on the nearest neighbour distance among xylem vessels, suggesting that vessels were closer to each other near the apex, and became progressively more distant toward the base. The spatial pattern of xylem vessels violated the assumption of complete spatial randomness, vessel spatial arrangement followed a uniform distribution at different distances from the tree base. Although there was an increase in the intensity and proximity among vessels, we demonstrated that no patterns of aggregation between vessels were found in sampled F. sylvatica trees. Rather, point pattern profiles clearly highlighted a lack of aggregation of vessels in the face of a regular spatial distribution in the annual growth rings along the stems.

We examined the localities and sites of the Mediterranean thermophyte Ruscus aculeatus in the southwestern part of the Julian Alps and confirmed its relatively frequent occurrence in the hilly and submontane belts up to 980 m a.s.l. It occurs predominantly on sunny aspects, gentle to very steep slopes and very stony (rocky) sites, in very different soil types and plant communities of deciduous forests, mainly with predominating tree species of Fraxinus excelsior, Carpinus betulus, Fagus sylvatica and Ostrya carpinifolia. Its northernmost sites known in Slovenia are in pioneer forests on abandoned agricultural areas in Breginjski Kot between Borjana and Sedlo, and on rockslide under the Polovnik ridge (Morizna), and are presumably younger in origin. Given the climate change (warming) in the last decades it is expected to spread further into the mountains (including the Bovec region). Key words: phytosociology, phytogeography, Ruscus aculeatus, Julian Alps, SloveniaSITES OF LOMELOSIA GRAMINIFOLIA (SCABIOSA GRAMINIFOLIA) ON THE NORTHEASTERNMOST KNOWN LOCALITY IN THE ALPS Izvleček Raziskali smo nahajališča in rastišča toploljubne mediteranske vrste Ruscus aculeatus (bodeča lobodika) v jugozahodnem delu Julijskih Alp in ugotovili njeno razmeroma pogosto uspevanje v gričevnem in podgorskem pasu, vse do nadmorske višine 980 m. Raste večinoma na prisojnih legah, na položnih do zelo strmih in zelo kamnitih (skalnatih) rastiščih, v zelo različnih talnih tipih in rastlinskih združbah listnatih gozdov, predvsem s prevladujočimi drevesnimi vrstami Fraxinus excelsior, Carpinus betulus, Fagus sylvatica in Ostrya carpinifolia. Njena do zdaj najbolj severozahodna nahajališča v Sloveniji, v pionirskih gozdovih na opuščenih kmetijskih površinah v Breginjskem kotu med Borjano in Sedlom in na podornem gradivu pod grebenom Polovnika (Morizna), so domnevno mlajšega izvora. Ob podnebnih spremembah (otoplitvi) zadnjih desetletij lahko pričakujemo njeno širjenje še bolj proti goram (tudi na Bovško). Ključne besede: fitocenologija, fitogeografija, Ruscus aculeatus, Julijske Alpe, Slovenija

In Poland and most of the areas of Europe, the beech, that is, Fagus sylvatica L. is one of the most vital species found in the species composition of forests. A number of the species of foliophages tend to develop on the leaves, which may contribute to the dieback of the tree. The demonstrated results are the effects of the research conducted in 2018 in the Cisów-Orłowiny Landscape Park. Subsequently, 11 species of foliophages were initially discovered there. Such species were inclined to form galls and the miner damages to the beech leaves. Among 4,000 of the analysed leaves, 398 galls and 498 leaf miner damages were found. They were caused by the representatives of insects and mites.

Foliar water uptake (FWU), the direct uptake of water into leaves, is a global phenomenon, having been observed in an increasing number of plant species. Despite the growing recognition of its functional relevance, our understanding of how FWU occurs and which foliar surface structures are implicated, is limited. In the present study, fluorescent and ionic tracers, as well as microcomputed tomography, were used to assess potential pathways for water entry in leaves of beech, a widely distributed tree species from European temperate regions. Although none of the tracers entered the leaf through the stomatal pores, small amounts of silver precipitation were observed in some epidermal cells, indicating moderate cuticular uptake. Trichomes, however, were shown to absorb and redistribute considerable amounts of ionic and fluorescent tracers. Moreover, microcomputed tomography indicated that 72% of empty trichomes refilled during leaf surface wetting and microscopic investigations revealed that trichomes do not have a cuticle but are covered with a pectin-rich cell wall layer. Taken together, our findings demonstrate that foliar trichomes, which exhibit strong hygroscopic properties as a result of their structural and chemical design, constitute a major FWU pathway in beech.

Common gardens are experimental plantations for comparing the performance of tree species while eliminating many of the variables that prevail in natural tree stands. The aim of this study was to evaluate the biodiversity of corticolous lichens on Danish tree species (Acer pseudoplatanus, Alnus glutinosa, Betula pendula, Fagus sylvatica, Fraxinus excelsior, Quercus robur and Tilia cordata) under common garden conditions and to examine the height distribution of particular lichen species. Observations were recorded through regular sampling of at least 36 lichen species on the main stems (from the base of the stem to the treetops) of 44-year-old trees at four common garden sites. Acer pseudoplatanus and Fraxinus excelsior had the greatest lichen species richness and Shannon diversity values while these measures were significantly lower for Betula pendula and Fagus sylvatica. The distribution of lichen species appeared biased among tree species. The general lichen distribution and relative sample height were weakly related (nonmetric multidimensional scaling). However, single lichen species showed a clear differential distribution along the tree stem (P Lepraria incana, Pseudosagedia aenea and Arthonia atra were mainly found at the stem base while Lecanora carpinea, L. chlarotera, Lecidella elaeochroma, Physcia tenella and Xanthoria parietina, were most abundant at around 70% of the total tree height. The differential distribution of single lichen species presumably reflects different specific requirements during spore germination and thallus growth. By isolating the unique effect of key variables (tree species and height), this study contributes to the knowledge base of corticolous lichen ecology.

We evaluated whether changes in fine root non-structural carbohydrate reserves of Fagus sylvatica and Pinus sylvestris trees influence potential enzymatic activities of their ectomycorrhizal symbionts from winter towards spring reactivation, and whether these changes influence potential soil enzymatic activities. We analyzed sugar and starch concentrations in the fine roots of Fagus sylvatica and Pinus sylvestris and potential activities of ß-glucosidase, ß-xylosidase, and cellobiohydrolase (as proxies for carbon-degrading enzymes) as well as leucine aminopeptidase and chitinase (as proxies for nitrogen-degrading enzymes) of their dominant ectomycorrhizal symbionts as well as in the soil. Sugar concentrations in the fine roots were significantly positively correlated with enzymatic activities of the ectomycorrhizal symbionts. In Pinus sylvestris, both carbon- and nitrogen-degrading enzyme activities showed significant positive correlations with fine root sugar concentrations. In Fagus sylvatica, fine root sugar concentrations were explicitly positively correlated with the activity of nitrogen-degrading enzymes. The chitinase activity in the soil was found to be strongly positively correlated with the enzymatic activity of the ectomycorrhizal symbionts as well as with fine root sugar concentrations. Fine root carbohydrate concentrations of Fagus sylvatica and Pinus sylvestris trees and enzymatic activities of their associated ectomycorrhizal fungi are connected. The specific nutrient demand of the tree species during spring reactivation may affect ectomycorrhizal enzymatic activity via carbon mobilization in the fine roots of Fagus sylvatica and Pinus sylvestris. Moreover, our results suggest that trees indirectly contribute to the degradation of fungal necromass by stimulating ectomycorrhizal chitinase activity in the soil.

The peculiarities of chemical elements accumulation by woody plants under conditions of Bytkiv-Babchynske oil deposit influence are investigated. X-ray fluorescence concentrations of aluminum, zinc, titanium, ferum, strontium, nickel, kuprum, arsenic, bromine, rubidium, molybdenum, palladium, argentum, plumbum, and vanadium in the dry mass of Acer platanoides L., Tilia cordata Mill., Fagus sylvatica L., Populus tremula L., Betula pendula Roth., Corylus avellana L. leaves under oil-contaminated environment are determined. With the help of CorelDRAW and ImageJ programs, the percentage of necrotized tissue of woody plants assimilation organs under the conditions of oil deposit is calculated. A direct proportional relationship between the necrotic lesions of leaf blades and the accumulation of chemical elements by plants is established. Absence of arsenic, bromine, molybdenum, palladium, argentum, plumbum, vanadium in Acer platanoides, Tilia cordata, Fagus sylvatica leaves is recorded. The growing content of chemical elements in the assimilation organs of the experimental trees is revealed in the following range: Mo → Pb → Pd → Ag → Br → As → V → Ni → Rb → Cu → Sr → Ti → Zn → Fe → Al. The percentage of leaf necrotization under conditions of Bytkiv-Babchynske oil deposit is increasing in a following range of experimental plants: Fagus sylvatica → Acer platanoides→ Tilia cordata → Populus tremula → Betula pendula → Corylus avellana. The maximum accumulative capacity of chemical elements is possessed by Corylus avellana L., minimum one – by Fagus sylvatica and Acer platanoides Because of the considerable cumulative resources of Corylus avellana, it is advisable to use the species as a phytoremediant of contaminated environment by chemical elements. Fagus sylvatica and Acer platanoides belong to the eliminator plants that absorb toxicants from the environment selectively and in small quantities due to the presence of powerful protective mechanisms in these species. Tilia cordata, Populus tremula and Betula pendula are marked by valuable bioindicator characteristics and can be used to assess the environmental stress level.

Stable carbon and oxygen isotope ratios of raw pollen sampled from nine abundant tree species growing in natural habitats of central and northern Europe were investigated to understand the intra- and inter-specific variability of pollen-isotope values. All species yielded specific δ13Cpollen and δ18Opollen values and patterns, which can be ascribed to their physiology and habitat preferences. Broad-leaved trees flowering early in the year before leaf proliferation (Alnus glutinosa and Corylus avellana) exhibited on average 2.6‰ lower δ13Cpollen and 3.1‰ lower δ18Opollen values than broad-leaved and coniferous trees flowering during mid and late spring (Acer pseudoplatanus, Betula pendula, Carpinus betulus, Fagus sylvatica, Picea abies, Pinus sylvestris and Quercus robur). Mean species-specific δ13Cpollen values did not change markedly over time, whereas δ18Opollen values of two consecutive years were often statistically distinct. An intra-annual analysis of B. pendula and P. sylvestris pollen revealed increasing δ18Opollen values during the final weeks of pollen development. However, the δ13Cpollen values remained consistent throughout the pollen-maturation process. Detailed intra-individual analysis yielded circumferential and height-dependent variations within carbon and oxygen pollen-isotopes and the sampling position on a tree accounted for differences of up to 3.5‰ for δ13Cpollen and 2.1‰ for δ18Opollen. A comparison of isotope ranges from different geographic settings revealed gradients between maritime and continental as well as between high and low altitudinal study sites. The results of stepwise regression analysis demonstrated, that carbon and oxygen pollen-isotopes also reflect local non-climate environmental conditions. A detailed understanding of isotope patterns and ranges in modern pollen is necessary to enhance the accuracy of palaeoclimate investigations on δ13C and δ18O of fossil pollen. Furthermore, pollen-isotope values are species-specific and the analysis of species growing during different phenophases may be valuable for palaeoweather reconstructions of different seasons.

Broadleaved tree species in mountainous populations usually demonstrate high levels of diversity in leaf morphology among individuals, as a response to a variety of environmental conditions associated with changes in altitude. We investigated the parameters shaping leaf morphological diversity in 80 beech individuals (Fagus sylvatica L.), in light and shade leaves, growing along an elevational gradient and under different habitat types on Mt. Paggeo in northeastern Greece. A clear altitudinal pattern was observed in the morphological leaf traits expressing lamina size and shape, with increasing altitude, trees had leaves with smaller laminas, less elongated outlines, and fewer pairs of secondary veins. However, this altitudinal trend in leaf morphology was varied in different habitat types. Furthermore, the shade leaves and light leaves showed differences in their altitudinal trend. Traits expressing lamina shape in shade leaves were more related to altitude, while leaf size appeared to be more influenced by habitat type. While the altitudinal trend in leaf morphology has been well documented for numerous broadleaved tree species, in a small spatial scale, different patterns emerged across different habitat types. This morphological variability among trees growing in a mountainous population indicates a high potential for adaptation to environmental extremes.

Filamentous fungi associated with woody tissues of European Beech (Fagus sylvatica) and isolated from diseased trees and healthy trees were examined in relation to their impact on tree health. To this end, classical culture-based isolation methods, in planta inoculations and fungal identification using ITS-barcode and morphological characters were used. Stem endophytes of healthy beech saplings collected in German forests were isolated to determine endophyte communities in woody stem tissues. Pathogenicity tests were performed on living potted beech saplings using twelve selected fungal pathogens and wood inhabiting fungi (Hypocreales, Botryosphaeriales, and Xylariales) originating mainly from European beech with symptoms of the complex disease Vitality loss, or from bark necroses, or known to be common endophytes of beech. The impact of these ascomycetous fungi with respect to tree health was discussed. The potential influences of endophytic fungi of beech and of test conditions are discussed in relation to the success of inoculation. All tested fungal strains except for Neonectria ditissima were able to establish themselves post inoculation in the beech stems and caused necroses when there was sufficient water, but at different severities. Under the experimental conditions, Botryosphaeria corticola was shown to be the most virulent tested latent pathogen against F. sylvatica. In the context of climate change and global warming, the tested Botryosphaeriaceae are able to play a primary role in the disease progress of Vitality loss of Beech. The key role of Neonectria coccinea in causing bark necroses and the loss of vitality in beech was confirmed because the tested strain induced large lesions on the beech saplings.

The wood species of 18th- and 19th-century Italian historic berlines (gala carriages mainly made of wood) housed in the Palazzo Pitti museum in Florence were investigated using non-destructive techniques based on the use of portable digital microscopes. Overall, thirteen wood taxa were identified. Among those, walnut (Juglans regia) was the most abundant species in berlines commissioned by noblemen of high rank, such as kings, princes and grand dukes, whereas in the other carriages of lower lineage, the walnut was replaced by elm (Ulmus sp.) wood, a species commonly used for carriages. Some species were typically present in specific parts of the structures, such as elm and ash (Fraxinus sp.) in the transoms and struts of the undercarriage, oak (Quercus sp.) in the wheel's spokes, poplar (Populus sp.) in the seats, panels and mouldings of the body and European beech (Fagus sylvatica) in the light frames. Species found only occasionally, including chestnut (Castanea sativa), fir (Abies alba) and spruce (Picea abies), may have been introduced in occasions of restoration or substitution. The results also showed a preference for the use of local species, which is different from carriages in other European countries where exotic species were already used.

Introduction Most secondary metabolites from plants have a prominent defensive role and repellency against predators and microbial pathogens. These properties largely vary among plant species and offer potential applications as biologically active compounds in medicine as well in agriculture. Objectives We propose a new procedure that combine different spectroscopic techniques and multivariate data analysis to determine the chemical composition and the relative amounts of each metabolites and/or each class of organic compounds. The approach was used for a rapid identification of secondary metabolites from leaf and root of eight Mediterranean plants species. Methodology The polar and the apolar extracts of two leaves and roots of each plant were analysed by proton nuclear magnetic resonance (1 H-NMR) and gas chromatography coupled to mass spectrometry (GC-MS), respectively. Multivariate data analysis was used for a faster interpretation of data. Results The metabolic fingerprint of the Mediterranean plants, Acanthus mollis, Dittrichia viscosa, Festuca drymeja, Fraxinus ornus, Fagus sylvatica, Hedera helix, Quercus ilex, and Typha latifolia, showed a complex chemical composition, being specific for each species and plant tissue. Two alditols, mannitol and quercitol, were found in manna ash (Fraxinus ornus) and holm oak (Q. ilex) polar leaf extracts, respectively. The highest levels of aromatic compounds were found in D. viscosa and T. latifolia. Fatty acids were the predominant class of compounds in all apolar extracts under investigation. Triterpene were almost exclusively found in roots, except for holm oak, where they constitute 58% of total extract. Steroids were widespread in leaf extracts. Conclusion The major advantages of the proposed approach are versatility and rapidity, thus making it suitable for a fast comparison among species and plant tissue types.

Phytoliths—also known as plant opals—are preserved in soils and sediments and have taxonomical relevance, therefore phytoliths can be fingerprints of the vegetation of the period from which they originated. Comparative phytolith studies are essential for finding phytolith morphotypes with taxonomic relevance. These are used to build reference collections for future palaeoecological and archaeobotanical studies. Biogenic silica extracted from the leaves of six woody species commonly occurring in temperate climate plant communities was examined using light and scanning electron microscope methods (Deciduous broad-leaved species: Corylus avellana, Fagus sylvatica, Quercus robur. Coniferous species: Abies alba, Picea abies, Pinus sylvestris). The element content of phytoliths was analysed by SEM EDX and the phytolith taxonomic diagnostic potential of element content was tested by discriminant analysis. An inventory of phytolith types with their anatomical origin was provided and type-frequencies were assessed. Three species have been systematically screened here for the first time in detail (C. avellana, F. sylvatica, Q. robur). This is the first time that a characteristic cubical phytolith morphotype (“Picea—blocky type”) originating from transfusion tissue was described as a distinct layer encompassing the central cylinder of the needle. High concentrations of aluminium and magnesium in phytoliths are associated with two of three conifer species. A. alba and P. sylvestris could be differentiated statistically on the basis of elemental content. Our findings open up the possibility to identify these taxa based on their phytoliths and it is anticipated that this could be a useful tool for phytolith identification originating from soils and sediments as well. Moreover, Picea—blocky type allows comparative, in situ studies (amongst others isotopic) to provide the possibility of finding further measurable proxies.

Drought events weaken trees and make them vulnerable to attacks by diverse plant pathogens. Here, we propose a molecular method for fast screening of microorganisms associated with European beech decline after an extreme drought period (2018) in a forest of Thuringia, Germany. We used Illumina sequencing with a recent bioinformatics approach based on DADA2 to identify archaeal, bacterial, and fungal ASVs (amplicon sequence variants) based on bacterial and archaeal 16S and fungal ITS genes. We show that symptomatic beech trees are associated with both bacterial and fungal plant pathogens. Although the plant pathogen sequences were detected in both discolored and non-discolored wood areas, they were highly enriched in the discolored wood areas. We show that almost each individual tree was associated with a different combination of pathogens. Cytospora spp. and Neonectria coccinea were among the most frequently detected fungal pathogens, whereas Erwinia spp. and Pseudomonas spp. were the dominant bacterial plant pathogens. We demonstrate that bacterial plant pathogens may be of major importance in beech decline.

Mineral nitrogen (N) is a major nutrient showing strong fluctuations in the environment due to anthropogenic activities. Acquisition and translocation of N to forest trees is achieved by highly diverse ectomycorrhizal fungi (EMF) living in symbioses with their host roots. Here, we examined colonized root tips to characterize the entire root-associated fungal community by DNA metabarcoding-Illumina sequencing of the fungal ITS2 molecular marker and used RNA sequencing to target metabolically active fungi and the plant transcriptome after N application. The study was conducted with beech (Fagus sylvatica L), a dominant tree species in central Europe, grown in native forest soil. We demonstrate strong enrichment of 15N from nitrate or ammonium in the ectomycorrhizal roots by stable isotope labeling. The relative abundance of the EMF members in the fungal community was correlated with their transcriptional abundances. The fungal metatranscriptome covered KEGG and KOG categories similar to model fungi and did not reveal significant changes related to N metabolization but species-specific transcription patterns, supporting trait stability. In contrast to the resistance of the fungal metatranscriptome, the transcriptome of the host exhibited dedicated nitrate- or ammonium-responsive changes with upregulation of transporters and enzymes required for nitrate reduction and drastic enhancement of glutamine synthetase transcript levels, indicating channeling of ammonium into the pathway for plant protein biosynthesis. Our results support that self-composed fungal communities associated with tree roots buffer nutritional signals in their own metabolism but do not shield plants from high environmental N.IMPORTANCEAlthough EMF are well known for their role in supporting tree N nutrition, the molecular mechanisms underlying N flux from the soil solution into the host through the ectomycorrhizal pathway remain widely unknown. Furthermore, ammonium and nitrate availability in the soil solution is subject to constant oscillations that create a dynamic environment for the tree roots and associated microbes during N acquisition. Therefore, it is important to understand how root-associated mycobiomes and the tree roots handle these fluctuations. We studied the response of the symbiotic partners by screening their transcriptomes after a sudden environmental flux of nitrate or ammonium. We show that the fungi and the host respond asynchronously, with the fungi displaying resistance to increased nitrate or ammonium, and the host dynamically metabolizing the supplied N sources. This study provides insights into the molecular mechanisms of the symbiotic partners operating under N enrichment in a multidimensional symbiotic system.

Members of the genus Fusarium and related genera are important components of many ecosystems worldwide and are responsible for many plant diseases. However, the structure of beech litter-inhabiting Fusarium communities and their potential role in reducing the natural regeneration of European beech are not well understood. To address this issue, we examined Fusarium communities in the litter of uneven-aged, old-growth beech-dominated forests in the Carpathians (Poland) and in the Alps (Austria), and in a managed beech stand (Poland). The fungi inhabiting beech litter were investigated using beechnuts and pine seedlings as bait. The pathogenicity of the most common species was investigated by inoculating beech germinants. Fusarium spp. were identified based on morphology and DNA sequence comparisons of RPB2 and TEF1-α genes, combined with phylogenetic analyses. Twelve fungal species were identified from 402 isolates, including nine known and three currently undescribed species. The isolates resided in three species complexes within the genus Fusarium. These were the F. oxysporum (one taxon), F. sambucinum (three taxa), and F. tricinctum (six taxa) species complexes. In addition, one isolate was assigned to the genus Neocosmospora, and one isolate could be placed within the genus Fusicolla. The most frequently isolated fungi from beechnuts and beech germinants were F. avenaceum (Fr.) Sacc., F. sporotrichioides Sherb. and Fusarium sp. B. The structure and abundance of species within Fusarium communities varied by beech forest type. The species richness of Fusarium spp. was greatest in old-growth beech-dominated stands, while abundances of Fusarium spp. were higher in managed beech-dominated stands. Pathogenicity tests showed that all four Fusarium species isolated from beechnuts and beech germinants could cause germinants to rot beech, suggesting that these fungi may play a negative role in the natural beech regeneration.

The results of interpopulation variability of morphometric parameters of European beech (Fagus sylvatica L.) seedlings originating from eight populations from the part of natural distribution area in Serbia are presented in this paper. The studied populations of Dubašnica, Jastrebac, Boranja, Fruška Gora, Mali Pek, Goč, Beljanica, and Javor have various ecological and vegetational characteristics. The results of this paper refer to root collar diameter and height of seedlings at the age of 1+0 and 2+0. Analysis of variance showed a statistically significant difference between the populations in terms of the studied morphological traits of seedlings (p

High-altitude tree populations are exposed to severe natural environmental conditions. Among abiotic factors, variable temperatures, early frosts, and high radiation are the factors affecting tree growth at high altitudes. Fagus sylvatica L. exhibits a variety of physiological and genetic traits that allow it to adapt to different forest habitats. This study examines the differences in the biochemical properties of senescing beech leaves between populations originating from different altitudes using a common-garden experiment. Leaves were collected from five-year-old plants from the beginning of August to the end of October for two years. Based on the changes in senescence marker levels the genetic differences and significant correlations between populations’ altitude origin and their biochemical characteristics were identified. According to the free radical theory of leaf senescence, reactive oxygen species (ROS) and senescence markers were highly correlated. In this study, populations from higher altitudes were characterized by earlier and greater increases in ROS content and oxidative stress, which resulted in higher antioxidative system activity. Increases in ROS in high-altitude populations play a controlling role to initiate earlier senescence processes that allow the trees to adapt to harsh climatic conditions. Earlier senescence allows beech trees to maintain a balance between nitrogen metabolism and photosynthetic activity. It allows for remobilization of nitrogen compounds more efficiently and protects the trees from nitrogen loss and prepares them for winter dormancy.

Transplants of beech, Fagus sylvatica, L. were planted in 1 m plastic tubes containing a mixture of peat and grit and sunk into the ground inside open-top chambers at a site in southern Britain. Chambers were ventilated with either charcoal-filtered or unfiltered air and water was withheld from half of the trees within each chamber. The influence of air quality on the growth and development of roots and interactions between air quality and drought were investigated. During May and June 1988 the growth of fine (diameter1.5 mm) and large roots (diameter1.5 m) was not significantly altered by air quality. A destructive harvest conducted in July revealed that trees exposed to ambient pollution had significantly longer roots (P0.05) compared with trees grown in filtered air, despite slightly less root dry weight (not statistically significant). Specific root length (SRL, root length per unit root dry weight) was also significantly larger (P0.05) for trees grown in the unfiltered chambers and exposed to pollution, suggesting a root system which was not only longer but also consisted of thinner roots, compared with the roots of trees grown in clean air. The effects of pollution were more pronounced for roots in the lower half of the 1 m profile. During August 1988, water was withheld from half of the trees within each chamber. Well-watered trees exposed to unfiltered air had significantly less root dry weight (P0.05) compared with well-watered trees grown in filtered air, although root length and SRL were both greater for trees grown in unfiltered air compared with those grown in filtered air. Again the effects were more pronounced lower in the root profile. Withholding water resulted in less root length being produced irrespective of air quality treatment, suggesting that trees exposed to pollution would not necessarily be more susceptible to drought-stress. Root length was also measured non-destructively in 1989 and again trees grown in unfiltered air had longer fine and large roots, compared with those grown in filtered air. These results illustrate the importance of measuring root length to complement estimates of dry weight, which may not be the best indicator of root function. The production of longer, thinner roots may be an important mechanism to compensate for reduced carbon allocation to, and dry matter accumulation by roots of trees exposed to pollution.

Summary • The effects of drought on European beech (Fagus sylvatica) were assessed in a pot experiment under controlled conditions. • Plants from 11 autochthonous provenances originating from regions in Germany, which differed in annual precipitation, were exposed to a 3-wk drought period in a glasshouse after the first stage of shoot growth had been completed. • Drought reduced the water content to 97% of control in leaves and axes and to 92% in the roots. A strong reduction of predawn water potential in roots and shoots, as well as on transpiration rate, was found. In the roots, the effect on water potential was the same for all provenances, but differences were observed in the shoot water potential. Leaf concentrations of abscisic acid (ABA), proline and sucrose increased in the drought-treated plants compared with the controls. • Two extreme clusters from opposite climatic sites were identified by cluster analysis. A drought-sensitive cluster, originating from regions with high annual precipitation, had low water potential and transpiration rates, as well as high concentrations of fructose, ABA and proline after drought. Water potential and transpiration rates were less affected by drought in the other cluster, which comprised two provenances of relatively dry habitats, and concentrations of hexose, ABA and proline were low.

Summary • In order to understand the phytohormone-like activity of humic substances (HS) with respect to vegetation, different forest ecosystems were considered. For this study, 32 soil horizons from a large area of northern Italy typical for silver fir ( Abies alba ) were evaluated. • The development of organic and humic matter in the five silver fir forest types was assessed by quantifying chemical and biochemical parameters. Phytohormone-like activity of HS was evaluated by measuring auxin-like (indoleacetic acid (IAA)-like) and gibberellin-like (GA-like) activities as well as invertase and peroxidase activities. • Differences between ecosystems were obtained by comparing the five silver fir types with previous work in beech forests, which investigated three large groups: thermophilous, mesophilous and acidophilous. In these eight forests it was reconfirmed that acid conditions were essential for the release of the IAA-like activity, whereas neutral conditions promoted GA-like activity. • Humic substances are of ecological importance because their phytohormone-like activity stands out not only within the five silver fir forest types, but also between the silver fir and beech types. Our results demonstrated a different collocation of the hormone-like activity along the profile in accordance with the different growth conditions, seed germination and the first stage of seedling growth. Humic substances evoke the greatest response on seed germination and on the first stage of seedling growth, particularly in stressed environmental conditions.

During the vegetation periods 1994 and 1995, net uptake of nitrate and ammonium by roots of adult spruce (Picea abies (L.) Karst) and beech (Fagus sylvatica L.) trees was studied at a field site exposed to high loads of N ('Hoglwald', Germany). In addition, uptake experiments were carried out under controlled conditions with young spruce and beech trees grown at normal N supply. In the field, nitrate was not taken up by the roots of spruce trees in appreciable amounts. This was also true for beech except during September 1995. Apparently, beech trees was capable of taking up nitrate, but the environmental condition prevailing at the field site usually prevented net uptake. Net uptake of ammonium in both tree species showed a seasonal course, with maximum rates in mid summer. Rates of ammonium uptake by both species correlated with soil temperature at the field site. Laboratory experiments on the influence of root temperature on uptake of nitrate indicated that uptake rates at temperatures found in the field were low compared with the uptake capacity at optimum temperature. At temperatures of 10 and 15°C, frequently found in the soil at the field site, net uptake of nitrate by spruce and beech amounted to c. 16% and 11%, respectively, of maximum uptake at 25°C. By contrast, net uptake of ammonium at 10°C reached 73% and 31% of the maximum uptake for spruce and beech trees, respectively. Independent of temperature, rates of nitrate uptake were considerably lower than those of ammonium. In young spruce and beech trees, net uptake of nitrate was significantly inhibited by ammonium at nitrate∶ammonium ratios found in the soil solution at the forest site. Preincubation of roots of both species, with amino acids present in the phloem of adult trees at the field site, led to an increase in the amino acid pool in the roots. For spruce trees a correlation between inhibition of uptake of nitrate and enrichment of the roots with the amino compounds Glu, γ-amino butyric acid (Gaba), Gln, and Asn was observed. In beech trees, enrichment of Asp and Gln in the roots correlated with a decrease in net uptake of nitrate. The results of laboratory experiments on the effects of temperature, the nitrate to ammonium ratio in the nutrient solution, and amino acid enrichment in the roots are discussed with special emphasis on the patterns of net uptake of ammonium and nitrate observed in the field.

The effects of ambient and elevated ozone levels on growth and photosynthesis of beech (Fagus sylvatica) were studied by exposing seedlings in open-top chambers for one growing season to three treatments: charcoal-filtered (CF), non-filtered (NF) and non-filtered air with addition of ozone (30 ppb ozone) on clear days for 8–10 h d−1 (NF +). Ambient levels were relatively low and accumulated to an AOT40 (accumulated exposure over a threshold of 40 ppb) of 4055 ppb h (for the period 23 Apr–30 Sept). The NF + chambers received an AOT40 of 8880 ppb h. Throughout the growing season we measured growth and photosynthetic properties. The treatments did not cause strong effects: measurements of gas exchange (light-saturated assimilation rate, CO2 and light-response curves) and chlorophyll fluorescence showed slight and mostly non-significant reductions of several parameters. No significant differences were found for growth, though in the NF + treatment (AOT40 8880 ppb h) the relative growth rate for diameter increment was at times reduced by 12% compared with the control treatment.

Aging is one of the most fundamental biological processes occurring in all forms of eukaryotic life. Beech trees (Fagus sylvatica L.) produce seeds in intervals of 5–10 years. Its yearly seed yield is usually very low, so there is a need for long-term seed storage to enable propagation of this species upon demand. Seeds for sowing must be of high quality but they are not easy to store without viability loss. Understanding the mechanism responsible for seed aging is therefore very important. We observed the generation of reactive oxygen species (ROS) in mitochondria of embryonic axes and cotyledons of beech seeds during natural aging. The presence of ROS led to changes in compromised mitochondrial membrane integrity and in mitochondrial metabolism and morphology. In this study, we pointed to the involvement of mitochondria in the natural aging process of beech seeds, but the molecular mechanisms underlying this involvement are still unknown.

Common beech is one of the most widespread and important European tree species, widely used in timber industry and for energy production. Under specific set of complex factors, it facutatetivly develops false heartwood, which considerably decreases market demand and value of processed logs. Due to its properties, false heartwood is more susceptible to attack of wood decay fungi, which leads to further loss of wood quality and value. One of the most common fungi able to cause heart rot in beech is Meripilus giganteus, known for its spread in the basal parts of the tree, where it can affect most valuable sections of round wood. The aims of this study were to monitor the distribution of fungus and appearance of its fruiting bodies in research area, and to analyze the extent of fungus impact on shape and size of false heartwood and occurrence and length of rot in infected trees, while taking into account the observed stem damage as a possible influential factor. Fruiting bodies occurrence, life span and position on a tree were monitored during a six-year period. For trees with confirmed infection, stem damage was evaluated and appointed to one of four size classes. False heartwood shape and share in associated stem cross-section were observed and measured on 1–4 cross-sections per tree at different heights, and compared between infected and uninfected trees. If present, length of wood decay extent on butt-log was measured. The obtained results confirmed increased susceptibility of mature trees to infection, which seemed to occur mostly via roots from where mycelium spread into stem base. It was found that Meripilus giganteus has a significant impact on enlargement and change of FH shape from cloud- to star-like, up to approximately 5 m of the stem height, thus causing devaluation of the first assortments. The presence of rot was confirmed on the majority of infected trees, extending averagely 0.5 m into the first processed log, causing the loss of utilizable volume and thus the value of round wood. Stem damage category showed no significant effect on false heartwood or rot, supporting the prevailing impact of the fungus.

U ovom radu prikazani su rezultati izmjere parametara koji opisuju fotosintetsku aktivnost bukovih klijanaca pod utjecajem suboptimalne ishranjenosti s mineralnim hranivima. Cilj rada bio je približiti ovu problematiku šumarskoj praksi kroz raspravu dobivenih rezultata u kontekstu dosadašnjih spoznaja o utjecaju mineralne ishrane na fotosintetski proces šumskoga drveća. U rano proljeće 2019. godine bukovi klijanci porijeklom iz jedne prirodne mješovite sastojine hrasta kitnjaka i obične bukve presađeni su u sterilni supstrat (agroperlit). Nakon presadnje redovito su zalijevani (tretirani) kompletnom hranivom otopinom (KO tretman), odnosno hranivim otopinama u kojima su izostavljeni dušik (–N tretman), fosfor (–P tretman), magnezij (–Mg tretman) ili željezo (–Fe tretman). Na šest klijanaca unutar svakog od pet prethodno opisanih tretmana tijekom vegetacijskog razdoblja 2019. godine redovito su mjereni sljedeći parametri: stopa fotosinteze (A), provodljivost puči (gs), intercelularna koncentracija CO2 (ci), indeks relativnog sadržaja klorofila u lišću (CCI) te indeks fotosintetske učinkovitosti (PIABS). Svi parametri bili su lošiji kod klijanaca iz –N, –P i –Mg tretmana u odnosu na klijance iz KO tretmana. Takav rezultat vjerojatno proizlazi iz fizioloških funkcija N, P i Mg koji sudjeluju u građi proteina i enzima, prometu i skladištenju energije te građi klorofila, što je sve skupa neophodno za uredno funkcioniranje cjelokupnog fotosintetskog procesa. Unatoč važnoj ulozi Fe u gotovo svim životnim procesima biljaka pa tako i fotosintezi svi mjereni parametri kod klijanaca iz –Fe i KO tretmana bili su podjednaki. Međutim, za razliku od N, P i Mg koji pripadaju skupini makrohraniva, Fe pripada skupini mikrohraniva, čije su koncentracije u biljnom tkivu relativno niske. Prema tome, moguće je pretpostaviti da su istraživani klijanci iz tla prirodne sastojine i/ili iz rezervi u sjemenu tijekom početne faze svoga razvoja uspjeli usvojiti i/ili mobilizirati dovoljnu količinu Fe koja im je bila dostatna za normalno funkcioniranje tijekom cijelog vegetacijskog razdoblja, bez obzira na kasniju primjenu tretmana. S obzirom na ovakav rezultat, inicijalno praćenje parametara fotosintetske aktivnosti bit će nastavljeno tijekom sljedećih nekoliko vegetacijskih razdoblja. U tom periodu planira se započeti s praćenjem dinamike vegetativnoga rasta, fenologije listanja i razvoja vizualnih simptoma pri suboptimalnoj ishranjenosti obične bukve s mineralnim hranivima s ciljem dodatnog približavanja ove problematike šumarskoj praksi.

Gall-inducing organisms change the chemical properties of galled organs and host plants due to the development of gall tissues that are supposed to shelter the galler and provide it with nutrients. Hartigiola annulipes and Mikiola fagi represent the gall midge family (Diptera; Cecidomyiidae). They share a host plant species, the common beech (Fagus sylvatica), whose leaves they use for galling. Their galls are single-chambered and occur on the upper side of the leaf blade. The morphologies of their galls are different, but there is a lack of studies comparing the impact of both species on the common host. Therefore, we analysed the total contents of carbon, nitrogen, soluble carbohydrates, starch, soluble phenolics and tannins in galls, galled leaves with removed galls and leaves without galls. Samples were collected in two different forest stands in western Poland (Scots pine forest with artificially planted beech trees and a natural beech forest). The influence of the studied gallers on the leaves is species- and forest-dependent. Perhaps seasonal changes and the level of infestation are also responsible for the chemical changes. The content of soluble carbohydrates in the galls of H. annulipes reaches an optimized level and is independent on the forest type. A high infestation level by H. annulipes is manifested itself in an elevated content of total soluble phenolics and tannins in leaves, while gall tissues do not accumulate soluble phenolics. The low levels of nitrogen in the gall tissues of both gallers leads to the rejection of the nutrition hypothesis; however, M. fagi galls act as sinks for soluble carbohydrates. Keywords: plant galls, chemistry, gall midge, common beech, biochemistry

Mycoparasites are a collection of fungicolous eukaryotic organisms that occur on and are antagonistic to a wide range of plant pathogenic fungi. To date, this fungal group has largely been neglected by biodiversity studies. However, this fungal group is of interest, as it may contain potential biocontrol agents of pathogenic fungi that cause beech Tarcrust disease (BTC), which has contributed to the devastation of European beech (Fagus sylvatica) forests. Biscogniauxia nummularia has been demonstrated to cause BTC. However, a trophic association between mycoparasites and pathogenic Biscogniauxia spp., has not been established. This study aimed to taxonomically identify and characterize Biscogniauxia, a fungus causing destructive BTC disease in European beech at Lovćen national park, Montenegro and to uncover the diversity of mycopathogens that are natural regulators of xylariaceous Biscogniauxia stroma formation, associated with beech decline. This finding is supported by distinctive phylogenetic and evolutionary characteristics, as well as unique morphological-microscopic fungal features indicating that Biscogniauxia from Montenegro, which is a major cause of BTC occurring in ancient beech forests at the edge of southern Fagus sylvatica distribution, may be described as a novel fungus specific to Fagus. Its evolutionary nuSSU&ndash, complete ITS&ndash, partial nuLSU rDNA phylogeny indicates its likely emergence by asexual fusion or introgressive hybridization between diverged B. nummularia and B. anceps species. The name Biscogniauxia destructiva is proposed for the novel fungus, as it is aggressive and highly destructive BTC disease.

This paper describes an experimental system designed for analysis of the dynamic water flow through young trees, complemented with test results of a 2-year-old beech tree (Fagus sylvatica L.). The system allows automatic and simultaneous measurements of a complex set of plant physiological processes at leaf, branch, stem and root levels [transpiration (E), sap flow (F) and diameter fluctuations (Δd)], in combination with the micrometeorological variables that control these processes [soil and air temperature (Ts and Ta), vapour pressure deficit of the air (D) and photosynthetically active radiation (PAR)]. A 2-d experimental period was used to study the whole-tree water transport dynamics of the young beech tree. Good correspondence between E of the leaves and F in the supporting branch was found. An increased time lag between the F measurements along the hydraulic pathway down towards the root system was observed, indicating the non-steady-state nature of the water flow. The daytime Δd of stem and branch revealed the depletion and the replenishment of internal water reserves. The daily amount of water withdrawn from internal storage was 5% of the total daily transpiration. A good linear relationship was found between the rate of change in internal water storage and the rate of change in stem diameter, having no time lag. We conclude that the data obtained with this system will allow experimental assessment of hydraulic properties in young trees and facilitate calibration of models for non-steady-state conditions of water flow in young trees.

Phosphorus (P) is an essential nutrient, but European forest ecosystems are experiencing widespread declines in soil P concentrations. To clarify the roles of ectomycorrhizal (EM) and saprotrophic (SAP) fungi in P cycling in forest soils that differ in inorganic and organic P availability, we conducted an ingrowth tube (IGT) experiment over 18 months of exposure in five beech (Fagus sylvatica L.) forests in Germany. To separate the contributions of both fungal guilds in situ, two different types of IGTs were used: (i) open IGTs with micromesh windows to allow EM fungi to regrow into the tubes, and (ii) closed IGTs (without mesh windows) in which recolonization by EM hyphae was restricted. We then measured phosphomonoesterase, phosphodiesterase, peroxidase, and phenoloxidase activities in EM (open IGTs) and SAP (closed IGTs) dominated fungal assemblages. Shifts in fungal assemblages occurred over time, but the speed and extent of those shifts differed between the five forest sites. In three forest sites fungal community composition shifted toward greater dominance of EM fungi in open IGTs than in closed IGTs after a period of 18 months, but these changes were not apparent in two other sites. Although shifts in fungal community composition were noticeable between treatments, we found no effect on phosphomonoesterase activity. Since phosphomonoesterase is present in both fungal guilds, this indicates functional redundancy of fungi. Phosphodiesterase activity was slightly reduced in SAP dominated IGTs, indicating that SAP fungi contribute to phosphodiesterase activity to a lesser extent than do EM fungi. P cycling enzymes did not appear to have been influenced by the total P stocks of the forest sites but may have been affected by additional abiotic factors. Contrary to our expectation, phenoloxidase activity was unaffected by fungal community composition, and only peroxidase activity was higher in SAP dominated IGTs, indicating that the contribution of EM fungi to degradation of complex organic material is driven by the need to obtain nutrients in addition to C. Overall, the results of this study contribute to a better understanding of the roles of EM and SAP fungi in P cycling in forest soils.

Belowground competition is an important structuring force in terrestrial plant communities. Uncertainties remain about the plasticity of functional root traits under competition, especially comparing interspecific vs. intraspecific situations. This study addresses the plasticity of fine root traits of competing Acer pseudoplatanus L. and Fagus sylvatica L. seedlings in nutrient-rich soil patches. Seedlings&rsquo, roots were grown in a competition chamber experiment in which root growth (biomass), morphological and architectural fine roots traits, and potential activities of four extracellular enzymes were analyzed. Competition chambers with one, two conspecific, or two allospecific roots were established, and fertilized to create a nutrient &lsquo, hotspot&rsquo, Interspecific competition significantly reduced fine root growth in Fagus only, while intraspecific competition had no significant effect on the fine root biomass of either species. Competition reduced root nitrogen concentration and specific root respiration of both species. Potential extracellular enzymatic activities of &beta, glucosidase (BG) and N-acetyl-glucosaminidase (NAG) were lower in ectomycorrhizal Fagus roots competing with Acer. Acer fine roots had greater diameter and tip densities under intraspecific competition. Fagus root traits were generally more plastic than those of Acer, but no differences in trait plasticity were found between competitive situations. Compared to Acer, Fagus roots possessed a greater plasticity of all studied traits but coarse root biomass. However, this high plasticity did not result in directed trait value changes under interspecific competition, but Fagus roots grew less and realized lower N concentrations in comparison to competing Acer roots. The plasticity of root traits of both species was thus found to be highly species- but not competitor-specific. By showing that both con- and allospecific roots had similar effects on target root growth and most trait values, our data sheds light on the paradigm that the intensity of intraspecific competition is greater than those of interspecific competition belowground.

Throughfall and stemflow are critical components of the hydrological and biogeochemical cycles of forested ecosystems, as they are the two hydrological processes responsible for the transfer of precipitation and solutes from vegetative canopies to the soil. Despite stemflow rarely accounts for >10% of the rainfall, its concentration over small areas at the base of trunks seems to affect the magnitude and timing of water inputs to the soil and biogeochemical cycling excessively.Though substantial amount of literature on throughfall and stemflow research is available, recent reviews on eco-hydrology of forested ecosystems identified several key points of uncertainty where current knowledge is weak. These points especially address the role of canopy structure among tree species (i.e., interspecific variation) as well as within a single tree species (i.e., intraspecific variation as caused e.g. by morphology and age) for explaining the large variations in precipitation partitioning into throughfall and stemflow, the spatial variability of throughfall volume and chemistry as well as the temporal and spatial patterning of stemflow inputs to the ground. The latter two points are particular sources of uncertainty, since most sampling approaches fail to adequately identify the infiltration area of stemflow inputs at the trunk base resulting in incomplete or biased evaluations of tree species effects on rainfall partitioning.Based on these deliberations we conducted a color tracer experiment with Brilliant Blue to identify flow patterns of stemflow water along the stem surface of two broad-leafed tree species (Fagus sylvatica and Acer pseudoplatanus) and to estimate the infiltration area at the trunk base and down to 12 cm soil depth. The trunk area was dye-stained up to 1.5 m height in advance and stemflow patterns along the trunk surface and soil infiltration zone were visually quantified following two natural rainfall events. Furthermore, we tested the relationship between color-stained zones of "high through-flow” and ecological soil characteristics such as fine root distribution and soil pH. This approach differs from common color tracer experiments, where stems are actively and homogeneously sprinkled with large amounts of color tracer solution.We found distinct spatially restricted stemflow pathways on the tree trunks, which appeared specific for the tree individual exhibiting larger washed-off areas for beech (4441 cm²) compared to maple (1816 cm²). The infiltration area of stemflow at the trunk base was smaller than the basal area (BA) amounting to 17% (226.2 cm²) of the BA for beech and to 30% (414.4 cm²) for maple. For beech, colored areas were restricted to a maximum extension of 13 cm distance from the stem and of 30 cm for maple.Our investigation exhibited that stemflow infiltration was spatially more concentrated at the trunk base than commonly assumed. The outcome of this study might contribute to our understanding on hydrological and biogeochemical interlinkages between the surface and subsurface of the Critical Zone.

Invasions by non-native pathogens represent a major threat to managed and natural ecosystems worldwide. Although necessary for adopting preventive strategies, the identification of invasive species before they are introduced is particularly difficult. Indeed, most pathogenic species that have become established in the last decades were first described only after they became invasive. To prevent further biological invasions, not only the early identification of potential new invasive plant pathogens is crucial, but also the assessment of their potential host range. In this study, we determined the pathogenicity and the saprotrophic ability of three Cryphonectria species towards three potential hosts in the family Fagaceae. For this, seedlings and dormant stems of European chestnut (Castanea sativa), pedunculate oak (Quercus robur) and European beech (Fagus sylvatica) were inoculated with different genotypes of C. parasitica (Asian species, invasive in Europe), C. naterciae (European species), and C. japonica (Asian species, not present in Europe). Lesion growth was measured and mortality assessed for four months. The highest damage was caused by C. parasitica on European chestnut, while C. japonica and C. naterciae induced significantly smaller lesions on this host species. All three Cryphonectria species did not grow saprophytically on F. sylvatica and Q. robur, but successfully colonized dormant stems of C. sativa. In the context of biological invasions, our study shows that the Asian C. japonica most likely represents a much less severe threat than C. parasitica for the tested European host species. Nonetheless, the ability of C. naterciae and C. japonica to saprotrophically colonize fresh chestnut wood may suggest that they could become established in chestnut forests and eventually infect weakened chestnut trees or other hosts not tested in this study.