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simulating stand climate, phenology, and photosynthesis of a forest stand with a process-based growth model.in the face of climate change and accompanying risks, forest management in europe is becoming increasingly important. model simulations can help to understand the reactions and feedbacks of a changing environment on tree growth. in order to simulate forest growth based on future climate change scenarios, we tested the basic processes underlying the growth model balance, simulating stand climate (air temperature, photosynthetically active radiation (par) and precipitation), tree phenology, and ph ...201020084520
girdling affects ectomycorrhizal fungal (emf) diversity and reveals functional differences in emf community composition in a beech forest.the relationships between plant carbon resources, soil carbon and nitrogen content, and ectomycorrhizal fungal (emf) diversity in a monospecific, old-growth beech (fagus sylvatica) forest were investigated by manipulating carbon flux by girdling. we hypothesized that disruption of the carbon supply would not affect diversity and emf species numbers if em fungi can be supplied by plant internal carbohydrate resources or would result in selective disappearance of emf taxa because of differences in ...201020097809
phytophthora morindae, a new species causing black flag disease on noni (morinda citrifolia l) in hawaii.a homothallic, papillate phytophthora species causing foliar and fruit blight of noni (morinda citrifolia var. citrifolia) in hawaii was identified. the asexual phase of this species is characterized by the production of umbellate sporangiophores and papillate sporangia that are ellipsoid and obpyriform with conspicuously tapered bases and possess caducous, medium to long pedicels. the sexual phase is characterized by the production of oogonia with tapered bases, small amphigynous antheridia and ...201020120235
development and verification of a water and sugar transport model using measured stem diameter variations.in trees, water and sugars are transported by xylem and phloem conduits which are hydraulically linked. a simultaneous study of both flows is interesting, since they concurrently influence important processes such as stomatal regulation and growth. a few mathematical models have already been developed to investigate the influence of both hydraulically coupled flows. however, none of these models has so far been tested using real measured field data. in the present study, a comprehensive whole-tr ...201020176887
biomass and nutrient content of sessile oak (quercus petraea (matt.) liebl.) and beech (fagus sylvatica l.) stem and branches in a mixed stand in southern belgium.accurate estimates of the amounts of nutrients immobilised in the organs and tissues of different tree species are of prime importance to make appropriate tree species selection and determine the harvesting regime that will ensure forest sustainability. sixteen sessile oaks (quercus petraea (matt.) liebl.) (64-129years; stem diameters: 17-57cm) and twelve beeches (fagus sylvatica l.) (43-86years; stem diameters: 9-50cm) were destructively sampled from a mixed stand located on an acid brown soil ...201020231032
proteomic approach to analyze dormancy breaking of tree seeds.in forest broadleaves from the temperate zone, a large number of species exhibit seed dormancy phenomena. tree seeds show some of the most pronounced and complicated forms of dormancy in the plant kingdom. many seeds are deeply physiologically dormant whatever their moisture level and age. however, dormancy can usually be overcome by a cold or warm stratification for several months. the transition from seed dormancy to germination is a multi-step process. in combination with the availability of ...201020306286
different atmospheric methane-oxidizing communities in european beech and norway spruce soils.norway spruce (picea abies) forests exhibit lower annual atmospheric methane consumption rates than do european beech (fagus sylvatica) forests. in the current study, pmoa (encoding a subunit of membrane-bound ch(4) monooxygenase) genes from three temperate forest ecosystems with both beech and spruce stands were analyzed to assess the potential effect of tree species on methanotrophic communities. a pmoa sequence difference of 7% at the derived protein level correlated with the species-level di ...201020348309
early events in populus hybrid and fagus sylvatica leaves exposed to ozone.this paper aims to investigate early responses to ozone in leaves of fagus sylvatica (beech) and populus maximowiczii x populus berolinensis (poplar). the experimental setup consisted of four open-air (oa) plots, four charcoal-filtered (cf) open-top chambers (otcs), and four nonfiltered (nf) otcs. qualitative and quantitative analyses were carried out on nonsymptomatic (cf) and symptomatic (nf and oa) leaves of both species. qualitative analyses were performed applying microscopic techniques: ev ...201020364237
the influence of climate and fructification on the inter-annual variability of stem growth and net primary productivity in an old-growth, mixed beech forest.the periodic production of large seed crops by trees (masting) and its interaction with stem growth has long been the objective of tree physiology research. however, very little is known about the effects of masting on stem growth and total net primary productivity (npp) at the stand scale. this study was conducted in an old-growth, mixed deciduous forest dominated by fagus sylvatica (l.) and covers the period from 2003 to 2007, which comprised wet, dry and regular years as well as two masts of ...201020453002
resurrection kinetics of photosynthesis in desiccation-tolerant terrestrial green algae (chlorophyta) on tree bark.the rough bark of orchard trees (malus) around darmstadt is predominantly covered in red to purple-brown layers (biofilms) of epiphytic terrestrial alga of trentepohlia umbrina. the smooth bark of forest trees (fagus sylvatica l. and acer sp.) in the same area is covered by bright green biofilms composed of the green algae desmococcus, apatococcus and trebouxia, with a few cells of coccomyxa and 'chlorella' trebouxioides between them. these algae are desiccation tolerant. after samples of bark w ...201020522179
competition for nitrogen sources between european beech (fagus sylvatica) and sycamore maple (acer pseudoplatanus) seedlings.to investigate the short-term consequences of direct competition between beech and sycamore maple on root n uptake and n composition, mycorrhizal seedlings of both tree species were incubated for 4 days (i.e. beech only, sycamore maple only or both together) in an artificial nutrient solution with low n availability. on the fourth day, n uptake experiments were conducted to study the effects of competition on inorganic and organic n uptake. for this purpose, multiple n sources were applied with ...201020522181
calcium is a major determinant of xylem vulnerability to cavitation.xylem vulnerability to cavitation is a key parameter in the drought tolerance of trees, but little is known about the control mechanisms involved. cavitation is thought to occur when an air bubble penetrates through a pit wall, and would hence be influenced by the wall's porosity. we first tested the role of wall-bound calcium in vulnerability to cavitation in fagus sylvatica. stems perfused with solutions of oxalic acid, egta, or sodium phosphate (napo(4)) were found to be more vulnerable to ca ...201020547703
mechanism of antibacterial activity of the white-rot fungus hypholoma fasciculare colonizing wood.in a previous study it was shown that the number of wood-inhabiting bacteria was drastically reduced after colonization of beech (fagus sylvatica) wood blocks by the white-rot fungus hypholoma fasciculare, or sulfur tuft (folman et al. 2008). here we report on the mechanisms of this fungal-induced antibacterial activity. hypholoma fasciculare was allowed to invade beech and pine (pinus sylvestris) wood blocks that had been precolonized by microorganisms from forest soil. the changes in the numbe ...201020555400
enhanced ozone strongly reduces carbon sink strength of adult beech (fagus sylvatica)--resume from the free-air fumigation study at kranzberg forest.ground-level ozone (o(3)) has gained awareness as an agent of climate change. in this respect, key results are comprehended from a unique 8-year free-air o(3)-fumigation experiment, conducted on adult beech (fagus sylvatica) at kranzberg forest (germany). a novel canopy o(3) exposure methodology was employed that allowed whole-tree assessment in situ under twice-ambient o(3) levels. elevated o(3) significantly weakened the c sink strength of the tree-soil system as evidenced by lowered photosynt ...201020570421
use of sap flow measurements to validate stomatal functions for mature beech (fagus sylvatica) in view of ozone uptake calculations.for a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. this technique was applied in three beech (fagus sylvatica) stands in switzerland. a canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. it represents mainly stoma ...201020580473
the presence of amino acids affects inorganic n uptake in non-mycorrhizal seedlings of european beech (fagus sylvatica).to investigate the impact of organic n compounds for inorganic nitrogen uptake in the rhizosphere, we fed ammonium nitrate with or without amino acids (i.e., glutamine or arginine) to the roots of non-mycorrhizal beech (fagus sylvatica l.) seedlings under controlled conditions at different levels of n availability. uptake of individual n sources was determined from ¹⁵n (inorganic n) and ¹⁵n ¹³c (organic n) accumulation in the roots. in addition, gene fragments encoding proteins involved in n upt ...201020595637
leaf litter decomposition in temperate deciduous forest stands with a decreasing fraction of beech (fagus sylvatica).we hypothesised that the decomposition rates of leaf litter will increase along a gradient of decreasing fraction of the european beech (fagus sylvatica) and increasing tree species diversity in the generally beech-dominated central european temperate deciduous forests due to an increase in litter quality. we studied the decomposition of leaf litter including its lignin fraction in monospecific (pure beech) stands and in stands with up to five tree genera (acer spp., carpinus betulus, fagus sylv ...201020596729
below-ground carbon allocation in mature beech and spruce trees following long-term, experimentally enhanced o3 exposure in southern germany.canopies of adult european beech (fagus sylvatica) and norway spruce (picea abies) were labeled with co(2) depleted in (13)c to evaluate carbon allocation belowground. one-half the trees were exposed to elevated o(3) for 6 yrs prior to and during the experiment. soil-gas sampling wells were placed at 8 and 15 cm and soil co(2) was sampled during labeling in mid-late august, 2006. in beech, delta(13)co(2) at both depths decreased approximately 50 h after labeling, reflecting rapid translocation o ...201020641169
ecology of coarse wood decomposition by the saprotrophic fungus fomes fomentarius.saprotrophic wood-inhabiting basidiomycetes are the most important decomposers of lignin and cellulose in dead wood and as such they attracted considerable attention. the aims of this work were to quantify the activity and spatial distribution of extracellular enzymes in coarse wood colonised by the white-rot basidiomycete fomes fomentarius and in adjacent fruitbodies of the fungus and to analyse the diversity of the fungal and bacterial community in a fungus-colonised wood and its potential eff ...201020668917
expanding leaves of mature deciduous forest trees rapidly become autotrophic.emerging leaves in evergreen tree species are supplied with carbon (c) from the previous year's foliage. in deciduous trees, no older leaves are present, and the early phase of leaf development must rely on c reserves from other tissues. how soon developing leaves become autotrophic and switch from being c sinks to sources has rarely been studied in mature forest trees, and simultaneous comparisons of species are scarce. using a canopy crane and a simple (13)co(2)-pulse-labelling technique, we d ...201020688879
host preferences and differential contributions of deciduous tree species shape mycorrhizal species richness in a mixed central european forest.mycorrhizal species richness and host ranges were investigated in mixed deciduous stands composed of fagus sylvatica, tilia spp., carpinus betulus, acer spp., and fraxinus excelsior. acer and fraxinus were colonized by arbuscular mycorrhizas and contributed 5% to total stand mycorrhizal fungal species richness. tilia hosted similar and carpinus half the number of ectomycorrhizal (em) fungal taxa compared with fagus (75 putative taxa). the relative abundance of the host tree the em fungal richnes ...201020886243
insights into xylem vulnerability to cavitation in fagus sylvatica l.: phenotypic and environmental sources of variability.xylem vulnerability to cavitation is a key parameter in understanding drought resistance of trees. we determined the xylem water pressure causing 50% loss of hydraulic conductivity (p(50)), a proxy of vulnerability to cavitation, and we evaluated the variability of this trait at tree and population levels for fagus sylvatica. we checked for the effects of light on vulnerability to cavitation of stem segments together with a time series variation of p(50). full sunlight-exposed stem segments were ...201020935319
seasonal dynamics in the stable carbon isotope composition δ¹³c from non-leafy branch, trunk and coarse root co₂ efflux of adult deciduous (fagus sylvatica) and evergreen (picea abies) trees.respiration is a substantial driver of carbon (c) flux in forest ecosystems and stable c isotopes provide an excellent tool for its investigation. we studied seasonal dynamics in δ¹³c of co₂ efflux (δ¹³c(e)) from non-leafy branches, upper and lower trunks and coarse roots of adult trees, comparing deciduous fagus sylvatica (european beech) with evergreen picea abies (norway spruce). in both species, we observed strong and similar seasonal dynamics in the δ¹³c(e) of above-ground plant components, ...201121054435
the ecological significance of phenology in four different tree species: effects of light and temperature on bud burst.the process of adaptation is the result of stabilising selection caused by two opposite forces: protection against an unfavourable season (survival adaptation), and effective use of growing resources (capacity adaptation). as plant species have evolved different life strategies based on different trade offs between survival and capacity adaptations, different phenological responses are also expected among species. the aim of this study was to compare budburst responses of two opportunistic speci ...201021113629
assessing the long-term species composition predicted by prognaus.tree growth models are supposed to contain stand growth laws as so called "emergent properties" which derive from interactions of individual-tree growth and mortality functions. this study investigates whether the evolving tree species composition in a long term simulation by the distance-independent tree growth model prognaus matches the species composition of the potential natural vegetation type which is expected to occur if one refrains from further management interventions and major disturb ...201021151325
in situ assessment of the velocity of carbon transfer by tracing (13) c in trunk co(2) efflux after pulse labelling: variations among tree species and seasons.• phloem is the main pathway for transferring photosynthates belowground. in situ(13) c pulse labelling of trees 8-10 m tall was conducted in the field on 10 beech (fagus sylvatica) trees, six sessile oak (quercus petraea) trees and 10 maritime pine (pinus pinaster) trees throughout the growing season. • respired (13) co(2) from trunks was tracked at different heights using tunable diode laser absorption spectrometry to determine time lags and the velocity of carbon transfer (v). the isotope com ...201121231935
carbon exchange between ecosystems and atmosphere in the czech republic is affected by climate factors.by comparing five ecosystem types in the czech republic over several years, we recorded the highest carbon sequestration potential in an evergreen norway spruce forest (100%) and an agroecosystem (65%), followed by european beech forest (25%) and a wetland ecosystem (20%). because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer s ...201121345558
ozone influence on native vegetation in the jizerske hory mts. of the czech republic: results based on ozone exposure and ozone-induced visible symptoms.ozone levels in the jizerske hory mts. measured at 13 sites by diffusive samplers during the 2006 and 2007 vegetation seasons are presented. a significant ozone gradient (5.4 ppb in 2006 and 4.0 ppb in 2007) per 100 m difference in altitude between 370 and 1,100 m a.s.l. was recorded. high-resolution maps of phytotoxic potential were developed. the aot40 threshold (5 ppm h) was exceeded over the entire area with the highest levels exceeding this threshold by 12 times in the upper portions of the ...201121374050
seasonal patterns of carbon allocation to respiratory pools in 60-yr-old deciduous (fagus sylvatica) and evergreen (picea abies) trees assessed via whole-tree stable carbon isotope labeling.• the co(2) efflux of adult trees is supplied by recent photosynthates and carbon (c) stores. the extent to which these c pools contribute to growth and maintenance respiration (r(g) and r(m), respectively) remains obscure. • recent photosynthates of adult beech (fagus sylvatica) and spruce (picea abies) trees were labeled by exposing whole-tree canopies to (13) c-depleted co(2). label was applied three times during the year (in spring, early summer and late summer) and changes in the stable c i ...201121395596
microbial processes and community composition in the rhizosphere of european beech - the influence of plant c exudates.plant roots strongly influence c and n availability in the rhizosphere via rhizodeposition and uptake of nutrients. this study aimed at investigating the effect of resource availability on microbial processes and community structure in the rhizosphere. we analyzed c and n availability, as well as microbial processes and microbial community composition in rhizosphere soil of european beech and compared it to the bulk soil. additionally, we performed a girdling experiment in order to disrupt root ...201121412402
spatial vs. temporal effects on demographic and genetic structures: the roles of dispersal, masting and differential mortality on patterns of recruitment in fagus sylvatica.trees' long lifespan, long-distance dispersal abilities and high year-to-year variability in fecundity are thought to have pervasive consequences for the demographic and genetic structure of recruited seedlings. however, we still lack experimental studies quantifying the respective roles of spatial processes such as restricted seed and pollen dispersal and temporal processes such as mast seeding on patterns of regeneration. dynamics of european beech (fagus sylvatica) seedling recruitment was mo ...201121426434
growth and posture control strategies in fagus sylvatica and acer pseudoplatanus saplings in response to canopy disturbance.forest tree saplings that grow in the understorey undergo frequent changes in their light environment to which they must adapt to ensure their survival and growth. crown architecture, which plays a critical role in light capture and mechanical stability, is a major component of sapling adaptation to canopy disturbance. shade-adapted saplings typically have plagiotropic stems and branches. after canopy opening, they need to develop more erect shoots in order to exploit the new light conditions. t ...201121444338
impacts of drought on mineral macro- and microelements in provenances of beech (fagus sylvatica l.) seedlings.beech seedlings originating from 11 german provenances with different climatic conditions were grown in pots and cultivated in a greenhouse. the composition of macro- and microelements in roots, axes and leaves was measured after half of the seedlings were subjected to a simulated summer drought. the recently described sensitivity of these provenances to drought was compared with drought-mediated changes in the elemental and ionic composition in organs of the seedlings; in addition, partitioning ...201121450981
is iron phloem mobile during senescence in trees? a reinvestigation of rissmüller's finding of 1874.as long as 130 years ago rissmüller reported substantial retranslocation of iron (fe) from beech leaves (fagus sylvatica l.) shortly before leaf fall. this rather limited report on fe retranslocation via the phloem in plants was the reason for this research to study changes in fe content in individual beech leaves in more detail during the vegetative period. besides fe, other micronutrients and particularly ca and k, well known to differ substantially in phloem mobility, were analysed as mineral ...201121486699
gene expression profiling in wounded and systemic leaves of fagus sylvatica reveals up-regulation of ethylene and jasmonic acid signalling.wounding is a crucial threat to plants because of the physical damage caused and the possible entry of pathogens. little is known about the wound reaction in forest trees. therefore, leaves of young beech trees were wounded and the transcriptional response of wounded leaves and leaves directly above and below was analysed. a total of 123 genes exhibited significant regulation. the magnitude of regulation was slightly weaker in the downward leaves but the regulation pattern resembles that of the ...201121489095
leaf traits, shoot growth and seed production in mature fagus sylvatica trees after 8 years of co2 enrichment.masting, i.e. synchronous but highly variable interannual seed production, is a strong sink for carbon and nutrients. it may, therefore, compete with vegetative growth. it is currently unknown whether increased atmospheric co(2) concentrations will affect the carbon balance (or that of other nutrients) between reproduction and vegetative growth of forest species. in this study, reproduction and vegetative growth of shoots of mature beech (fagus sylvatica) trees grown at ambient and elevated atmo ...201121493641
do interactions between plant and soil biota change with elevation? a study on fagus sylvatica.theoretical models predict weakening of negative biotic interactions and strengthening of positive interactions with increasing abiotic stress. however, most empirical tests have been restricted to plant-plant interactions. no empirical study has examined theoretical predictions of interactions between plants and below-ground micro-organisms, although soil biota strongly regulates plant community composition and dynamics. we examined variability in soil biota effects on tree regeneration across ...201121525055
functional analysis in arabidopsis of fsptp1, a tyrosine phosphatase from beechnuts, reveals its role as a negative regulator of aba signaling and seed dormancy and suggests its involvement in ethylene signaling modulation.by means of an rt-pcr approach we isolated a specific tyrosine phosphatase (fsptp1) induced by abscisic acid (aba) and correlated with seed dormancy in fagus sylvatica seeds. to provide genetic evidence of fsptp1 function in seed dormancy and aba signal transduction pathway, we overexpressed this gene in cape verde island ecotype of arabidopsis thaliana, which shows the deepest degree of seed dormancy among arabidopsis accessions. as a result, 35s:fsptp1 transgenic seeds showed a reduced dormanc ...201121567167
patterns of lignin degradation and oxidative enzyme secretion by different wood- and litter-colonizing basidiomycetes and ascomycetes grown on beech-wood.the degradation of lignocellulose and the secretion of extracellular oxidoreductases were investigated in beech-wood (fagus sylvatica) microcosms using 11 representative fungi of four different ecophysiological and taxonomic groups causing: (1) classic white rot of wood (e.g. phlebia radiata), (2) 'nonspecific' wood rot (e.g. agrocybe aegerita), (3) white rot of leaf litter (stropharia rugosoannulata) or (4) soft rot of wood (e.g. xylaria polymorpha). all strong white rotters produced manganese- ...201121631549
ectomycorrhizal fungal diversity, tree diversity and root nutrient relations in a mixed central european forest.knowledge is limited about whether root nutrient concentrations are affected by mixtures of tree species and interspecific root competition. the goal of this field study was to investigate root nutrient element concentrations in relation to root and ectomycorrhizal (em) diversity in six different mixtures of beech (fagus sylvatica), ash (fraxinus excelsior) and lime (tilia sp.) in an old-growth, undisturbed forest ecosystem. root biomass and nutrient concentrations per tree taxon as well as the ...201121636693
soil respiration rates and δ13c(co2) in natural beech forest (fagus sylvatica l.) in relation to stand structure.soil respiration rates were studied as a function of soil type, texture and light intensity at five selected natural beech forest stands with contrasting geology: stands on silicate bedrock at kladje and bricka in pohorje, a stand on quartz sandstone at vrhovo and two stands on a carbonate bedrock in the karstic-dinaric area in kocevski rog, snezna jama and rajhenav, slovenia, during the growing season in 2005-2006. soil respiration exhibited pronounced seasonal and spatial variations in the stu ...201121644135
a new conceptual model for the fate of lignin in decomposing plant litter.lignin is a main component of plant litter. its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. we studied the relationships between lignin degradation and the production of dissolved organic carbon (doc) and of co2 during litter decomposition. needle or leaf litter of five species (norway spruce, scots pine, mountain ash, european beech, sycamore maple) and of different decomposition stage (freshly fallen and up to 27 months of field ...201121661566
phenols in leaves and bark of fagus sylvatica as determinants of insect occurrences.beech forests play an important role in temperate and north mediterranean ecosystems in greece since they occupy infertile montane soils. in the last glacial maximum, fagus sylvatica (beech) was confined to southern europe where it was dominant and in the last thousand years has expanded its range to dominate central europe. we sampled four different beech forest types. we found 298 insect species associated with beech trees and dead beech wood. while f. sylvatica and quercus (oak) are confamili ...201121686149
simulated nitrogen deposition affects wood decomposition by cord-forming fungi.anthropogenic nitrogen (n) deposition affects many natural processes, including forest litter decomposition. saprotrophic fungi are the only organisms capable of completely decomposing lignocellulosic (woody) litter in temperate ecosystems, and therefore the responses of fungi to n deposition are critical in understanding the effects of global change on the forest carbon cycle. plant litter decomposition under elevated n has been intensively studied, with varying results. the complexity of fores ...201121735202
soil matrix tracer contamination and canopy recycling did not impair ¹³co₂ plant-soil pulse labelling experiments.when conducting (13)co(2) plant-soil pulse labelling experiments, tracer material might cause unwanted side effects which potentially affect δ(13)c measurements of soil respiration (δ(13)c(sr)) and the subsequent data interpretation. first, when the soil matrix is not isolated from the atmosphere, contamination of the soil matrix with tracer material occurs leading to a physical back-diffusion from soil pores. second, when using canopy chambers continuously, (13)co(2) is permanently re-introduce ...201121756196
the diel imprint of leaf metabolism on the δ13 c signal of soil respiration under control and drought conditions.recent (13) co(2) canopy pulse chase labeling studies revealed that photosynthesis influences the carbon isotopic composition of soil respired co(2) (δ(13) c(sr)) even on a diel timescale. however, the driving mechanisms underlying these short-term responses remain unclear, in particular under drought conditions. the gas exchange of co(2) isotopes of canopy and soil was monitored in drought/nondrought-stressed beech (fagus sylvatica) saplings after (13) co(2) canopy pulse labeling. a combined ca ...201121851360
seasonal changes of c and n non-structural compounds in the stem sapwood of adult sessile oak and beech trees.we assessed the pools of non-structural nitrogen compounds (nsnc) through a year, thereby addressing the question of whether mature sessile oak [quercus petraea (matt.) liebl.] and beech (fagus sylvatica l.), which differ in wood anatomy and growth patterns, exhibit contrasting seasonal dynamics of nsnc pools as previously shown for non-structural carbohydrate (nsc) pools. seasonal fluctuations of nsnc (amino acids and soluble proteins) and nsc (starch and soluble sugars) pools were analyzed in ...201121856656
mechanical behaviour analyses of sap ascent in vascular plants.a pure mechanical anisotropic model of a tree trunk has been developed based on the 3d finite element method. it simulates the microscopic structure of vessels in the trunk of a european beech (fagus sylvatica) in order to study and analyse its mechanical behaviour with different configurations of pressures in the conduits of xylem and phloem. the dependence of the strains at the inner bark was studied when sap pressure changed. the comparison with previously published experimental data leads to ...201021886343
comparison of pollen gene flow among four european beech (fagus sylvatica l.) populations characterized by different management regimes.the study of the dispersal capability of a species can provide essential information for the management and conservation of its genetic variability. comparison of gene flow rates among populations characterized by different management and evolutionary histories allows one to decipher the role of factors such as isolation and tree density on gene movements. we used two paternity analysis approaches and different strategies to handle the possible presence of genotyping errors to obtain robust esti ...201221897442
to what extent is altitudinal variation of functional traits driven by genetic adaptation in european oak and beech?the phenotypic responses of functional traits in natural populations are driven by genetic diversity and phenotypic plasticity. these two mechanisms enable trees to cope with rapid climate change. we studied two european temperate tree species (sessile oak and european beech), focusing on (i) in situ variations of leaf functional traits (morphological and physiological) along two altitudinal gradients and (ii) the extent to which these variations were under environmental and/or genetic control u ...201121908436
the long way down--are carbon and oxygen isotope signals in the tree ring uncoupled from canopy physiological processes?the carbon (δ(13)c) and oxygen (δ(18)o) stable isotope composition is widely used to obtain information on the linkages between environmental drivers and tree physiology over various time scales. the tree-ring archive can especially be exploited to reconstruct inter- and intra-annual variation of both climate and physiology. there is, however, a lack of information on the processes potentially affecting δ(13)c and δ(18)o on their way from assimilation in the leaf to the tree ring. as a consequen ...201121957095
genotypic variability and phenotypic plasticity of cavitation resistance in fagus sylvatica l. across europe.xylem cavitation resistance is a key physiological trait correlated with species tolerance to extreme drought stresses. little is known about the genetic variability and phenotypic plasticity of this trait in natural tree populations. here we measured the cavitation resistance of 17 fagus sylvatica populations representative of the full range of the species in europe. the trees were grown in three field trials under contrasting climatic conditions. our findings suggest that the genotypic variabi ...201121989814
reconstruction of a beech population bottleneck using archival demographic information and bayesian analysis of genetic data.range expansion and contraction has occurred in the history of most species and can seriously impact patterns of genetic diversity. historical data about range change are rare and generally appropriate for studies at large scales, whereas the individual pollen and seed dispersal events that form the basis of geneflow and colonization generally occur at a local scale. in this study, we investigated range change in fagus sylvatica on mont ventoux, france, using historical data from 1838 to the pre ...201122097929
multiplexed microsatellite markers for genetic studies of beech.european beech (fagus sylvatica l.) is one of the economically most important broadleaved tree species in europe and has become a model for studying climate change effects on forests. multiplex pcr of microsatellites is a fast and cost-effective technique allowing high-throughput genotyping. here we present the procedure used to develop two multiplex kits (8-plexes) for european beech. we paid particular attention to quality control throughout all steps of the multiplex kits development (null al ...201222145937
Are gastropods, rather than ants, important dispersers of seeds of myrmecochorous forest herbs?Abstract Seed dispersal by ants (myrmecochory) is widespread, and seed adaptations to myrmecochory are common, especially in the form of fatty appendices (elaiosomes). In a recent study, slugs were identified as seed dispersers of myrmecochores in a central European beech forest. Here we used 105 beech forest sites to test whether myrmecochore presence and abundance is related to ant or gastropod abundance and whether experimentally exposed seeds are removed by gastropods. Myrmecochorous plant ...201222173465
N(2) fixation and cycling in Alnus glutinosa, Betula pendula and Fagus sylvatica woodland exposed to free air CO(2) enrichment.We measured the effect of elevated atmospheric CO(2) on atmospheric nitrogen (N(2)) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N(2)-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N(2) fixation in A. glutinosa will increase in response to increased atmospheric CO(2) concentrations, when growing in monoculture, (2) the impact of elevated CO(2) on N(2) fixation in A. glutinosa is the same in mixture an ...201122179329
The occurrence and rapid discrimination of Fomes fomentarius genotypes by ITS-RFLP analysis.Sequence comparison of available Fomes fomentarius (L.) J. Kickx f. internal transcribed spacer (ITS) of ribosomal DNA sequences demonstrated genetic non-homogeneity of the species. Multiple sequence alignment indicated the presence of two genotypes with overall similarity of about 97% and a strong statistics support. Rapid and reliable method for discrimination of F. fomentarius genotypes based on restriction digestion of polymerase chain reaction (PCR)-amplified ITS sequences was developed. Bs ...201222208610
inhibitory effects of pentosan polysulfate sodium on map-kinase pathway and nf-κb nuclear translocation in canine chondrocytes in vitro.pentosan polysulfate sodium (pps) has a heparin-like structure and is purificated from the plant of european beech wood. pps has been used for the treatment of interstitial cystitis for human patients. recent years, it was newly recognised that pps reduce pain and inflammation of oa. the molecular biological mechanism of pps to express its clinical effects is not fully understood. the purpose of the present study is to investigate a mechanism of action of pps on inflammatory reaction of chondroc ...201122214865
status of the southern carpathian forests in the long-term ecological research network.air pollution, bulk precipitation, throughfall, soil condition, foliar nutrients, as well as forest health and growth were studied in 2006-2009 in a long-term ecological research (lter) network in the bucegi mountains, romania. ozone (o(3)) was high indicating a potential for phytotoxicity. ammonia (nh(3)) concentrations rose to levels that could contribute to deposition of nutritional nitrogen (n) and could affect biodiversity changes. higher that 50% contribution of acidic rain (ph < 5.5) cont ...201222234644
metatranscriptomics reveals the diversity of genes expressed by eukaryotes in forest soils.eukaryotic organisms play essential roles in the biology and fertility of soils. for example the micro and mesofauna contribute to the fragmentation and homogenization of plant organic matter, while its hydrolysis is primarily performed by the fungi. to get a global picture of the activities carried out by soil eukaryotes we sequenced 2×10,000 cdnas synthesized from polyadenylated mrna directly extracted from soils sampled in beech (fagus sylvatica) and spruce (picea abies) forests. taxonomic af ...201222238585
comparison of leaf gas exchange and stable isotope signature of water-soluble compounds along canopy gradients of co-occurring douglas-fir and european beech.combined δ(13) c and δ(18) o analyses of water-soluble leaf and twig phloem material were used to determine intrinsic water-use efficiency (iwue) and variability of stomatal conductance at different crown positions in adult european beech (fagus sylvatica) and douglas-fir (pseudotsuga menziesii) trees. simultaneous gas exchange measurements allowed evaluation of the differences in calculating iwue from leaf or phloem water-soluble compounds, and comparison with a semi-quantitative dual isotope m ...201222292498
throughfall deposition and canopy exchange processes along a vertical gradient within the canopy of beech (fagus sylvatica l.) and norway spruce (picea abies (l.) karst).to assess the impact of air pollution on forest ecosystems, the canopy is usually considered as a constant single layer in interaction with the atmosphere and incident rain, which could influence the measurement accuracy. in this study the variation of througfall deposition and derived dry deposition and canopy exchange were studied along a vertical gradient in the canopy of one european beech (fagus sylvatica l.) tree and two norway spruce (picea abies (l.) karst) trees. throughfall and net thr ...201222325986
wide variation in spatial genetic structure between natural populations of the european beech (fagus sylvatica) and its implications for sgs comparability.identification and quantification of spatial genetic structure (sgs) within populations remains a central element of understanding population structure at the local scale. understanding such structure can inform on aspects of the species' biology, such as establishment patterns and gene dispersal distance, in addition to sampling design for genetic resource management and conservation. however, recent work has identified that variation in factors such as sampling methodology, population characte ...201222354112
effect of flooding on c metabolism of flood-tolerant (quercus robur) and non-tolerant (fagus sylvatica) tree species.flooding is assumed to cause an energy crisis in plants because-due to a lack of o(2)-mitochondrial respiration is replaced by alcoholic fermentation which yields considerably less energy equivalents. in the present study, the effect of flooding on the carbon metabolism of flooding-tolerant pedunculate oak (quercus robur l.) and flooding-sensitive european beech (fagus sylvatica l.) seedlings was characterized. whereas soluble carbohydrate concentrations dropped in roots of f. sylvatica, they we ...201222367762
tree litter and forest understorey vegetation: a conceptual framework to understand the effects of tree litter on a perennial geophyte, anemone nemorosa.litter is a key factor in structuring plant populations, through positive or negative interactions. the litter layer forms a mechanical barrier that is often strongly selective against individuals lacking hypocotyle plasticity. litter composition also interacts with plant growth by providing beneficial nutrients or, inversely, by allowing harmful allelopathic leaching. as conspicuous litter fall accumulation is often observed under deciduous forests, interactions between tree litter and understo ...201222419760
use of thermal imaging to determine leaf conductance along a canopy gradient in european beech (fagus sylvatica).using an infrared camera, we measured the leaf temperature across different canopy positions of a 23-m-tall deciduous forest tree (fagus sylvatica l.) including typical sun and shade leaves as well as intermediate leaf forms, which differed significantly in specific leaf area (sla). we calculated a temperature index (i(g)) and a crop water stress index (cwsi) using the surface temperatures of wet and dry reference leaves. additional indices were computed using air temperature plus 5 °c (i(g) + 5 ...201222427372
drought-adaptation potential in fagus sylvatica: linking moisture availability with genetic diversity and dendrochronology.microevolution is essential for species persistence especially under anticipated climate change scenarios. species distribution projection models suggested that the dominant tree species of lowland forests in switzerland, european beech (fagus sylvatica l.), might disappear from most areas due to expected longer dry periods. however, if genotypes at the moisture boundary of the species climatic envelope are adapted to lower moisture availability, they can serve as seed source for the continuatio ...201222448260
how closely does stem growth of adult beech (fagus sylvatica) relate to net carbon gain under experimentally enhanced ozone stress?the hypothesis was tested that o(3)-induced changes in leaf-level photosynthetic parameters have the capacity of limiting the seasonal photosynthetic carbon gain of adult beech trees. to this end, canopy-level photosynthetic carbon gain and respiratory carbon loss were assessed in european beech (fagus sylvatica) by using a physiologically based model, integrating environmental and photosynthetic parameters. the latter were derived from leaves at various canopy positions under the ambient o(3) r ...201222487316
effect of habitat fragmentation on the genetic diversity and structure of peripheral populations of beech in central italy.fragmentation can affect the demographic and genetic structure of populations near the boundary of their biogeographic range. higher genetic differentiation among populations coupled with lower level of within-population variability is expected as a consequence of reduced population size and isolation. the effects of these 2 factors have been rarely disentangled. given their high gene flow, anemophilous forest trees should be more affected, in terms of loss of genetic diversity, by small populat ...201222496339
effects of a triazole fungicide and a pyrethroid insecticide on the decomposition of leaves in the presence or absence of macroinvertebrate shredders.previously, laboratory experiments have revealed that freely diluted azole fungicides potentiate the direct toxic effect of pyrethroid insecticides on daphnia magna. more ecologically relevant exposure scenarios where pesticides are adsorbed have not been addressed. in this study we exposed beech leaves (fagus sylvatica) to the azole fungicide propiconazole (50 or 500 μg l(-1)), the pyrethroid insecticide alpha-cypermethrin (0.1 or 1 μg l(-1)) or any combination of the two for 3h. exposed leaves ...201222516675
monitoring of ozone effects on the vitality and increment of norway spruce and european beech in the central european forests.the ozone effect on norway spruce (picea abies (l) karst.) and european beech (fagus sylvatica l.) was studied on 48 monitoring plots in 2005-2008. these plots represent two major forest tree species stands of different ages in eight regions of the czech republic. the forest conditions were represented by defoliation and the annual radial increment of individual trees. the ozone exposure was assessed by using modeled values of mean annual o(3) concentration and the aot40 index. the malondialdehy ...201222534676
loss of epiphytic diversity along a latitudinal gradient in southern europe.latitudinal gradients that involve macroclimatic changes can affect the diversity of several groups of plants and animals. here we examined the effect of a latitudinal gradient on epiphytic communities on a single host species (fagus sylvatica) to test the core-periphery theory. the latitudinal span considered, covering two biogeographic regions, is associated with major changes in rainfall during the dry season. because bryophytes and lichens are poikilohydric, we hypothesized that their specie ...201222542233
light-mediated k(leaf) induction and contribution of both the pip1s and pip2s aquaporins in five tree species: walnut (juglans regia) case study.understanding the response of leaf hydraulic conductance (k(leaf)) to light is a challenge in elucidating plant-water relationships. recent data have shown that the effect of light on k(leaf) is not systematically related to aquaporin regulation, leading to conflicting conclusions. here we investigated the relationship between light, k(leaf), and aquaporin transcript levels in five tree species (juglans regia l., fagus sylvatica l., quercus robur l., salix alba l. and populus tremula l.) grown i ...201222544048
sensitivity of beech trees to global environmental changes at most north-eastern latitude of their occurrence in europe.the present study aimed to detect sensitivity of beech trees (fagus sylvatica l.) to meteorological parameters and air pollution by acidifying species as well as to surface ozone outside their north-eastern distribution range. data set since 1981 of preila emep station enabled to establish that hot summers, cold dormant, and dry and cold first-half of vegetation periods resulted in beech tree growth reduction. these meteorological parameters explained 57% variation in beech tree ring widths. aci ...201222649321
novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. part 2. laboratory validation.sap flow measurements conducted with thermal dissipation probes (tdps) are vulnerable to natural temperature gradient (ntg) bias. few studies, however, attempted to explain the dynamics underlying the ntg formation and its influence on the sensors' signal. this study focused on understanding how the tdp signals are affected by negative and positive temperature influences from ntg and tested the novel cyclic heat dissipation (chd) method to filter out the ntg bias. a series of three experiments w ...201222659459
stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter.resource stoichiometry (c:n:p) is an important determinant of litter decomposition. however, the effect of elemental stoichiometry on the gross rates of microbial n and p cycling processes during litter decomposition is unknown. in a mesocosm experiment, beech (fagus sylvatica l.) litter with natural differences in elemental stoichiometry (c:n:p) was incubated under constant environmental conditions. after three and six months, we measured various aspects of nitrogen and phosphorus cycling. we f ...201222690628
comparing the intra-annual wood formation of three european species (fagus sylvatica, quercus petraea and pinus sylvestris) as related to leaf phenology and non-structural carbohydrate dynamics.monitoring cambial phenology and intra-annual growth dynamics is a useful approach for characterizing the tree growth response to climate change. however, there have been few reports concerning intra-annual wood formation in lowland temperate forests with high time resolution, especially for the comparison between deciduous and coniferous species. the main objective of this study was to determine how the timing, duration and rate of radial growth change between species as related to leaf phenolo ...201222718524
influence of litter chemistry and stoichiometry on glucan depolymerization during decomposition of beech (fagus sylvatica l.) litter.glucans like cellulose and starch are a major source of carbon for decomposer food webs, especially during early- and intermediate-stages of decomposition. litter quality has previously been suggested to notably influence decomposition processes as it determines the decomposability of organic material and the nutrient availability to the decomposer community. to study the impact of chemical and elemental composition of resources on glucan decomposition, a laboratory experiment was carried out us ...201222761539
multivariate analysis of physiological parameters reveals a consistent o3 response pattern in leaves of adult european beech (fagus sylvatica).• increasing atmospheric concentrations of phytotoxic ozone (o(3) ) can constrain growth and carbon sink strength of forest trees, potentially exacerbating global radiative forcing. despite progress in the conceptual understanding of the impact of o(3) on plants, it is still difficult to detect response patterns at the leaf level. • here, we employed principal component analysis (pca) to analyse a database containing physiological leaf-level parameters of 60-yr-old fagus sylvatica (european beec ...201222775349
sapflow+: a four-needle heat-pulse sap flow sensor enabling nonempirical sap flux density and water content measurements.• to our knowledge, to date, no nonempirical method exists to measure reverse, low or high sap flux density. moreover, existing sap flow methods require destructive wood core measurements to determine sapwood water content, necessary to convert heat velocity to sap flux density, not only damaging the tree, but also neglecting seasonal variability in sapwood water content. • here, we present a nonempirical heat-pulse-based method and coupled sensor which measure temperature changes around a linea ...201222816502
seasonal dynamics of arboreal spider diversity in a temperate forest.measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and inform management decisions. most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often-at least tacitly-assumed that these short-term findings are representative of long-term general patterns. however, should the studied biodiversity pattern in fact contain significant temporal dynamics, perh ...201222837825
phenological mismatch strongly affects individual fitness but not population demography in a woodland passerine.populations are shifting their phenology in response to climate change, but these shifts are often asynchronous among interacting species. resulting phenological mismatches can drive simultaneous changes in natural selection and population demography, but the links between these interacting processes are poorly understood. here we analyse 37 years of data from an individual-based study of great tits (parus major) in the netherlands and use mixed-effects models to separate the within- and across- ...201322862682
fagus sylvatica trunk epicormics in relation to primary and secondary growth.european beech epicormics have received far less attention than epicormics of other species, especially sessile oak. however, previous work on beech has demonstrated that there is a negative effect of radial growth on trunk sprouting, while more recent investigations on sessile oak proved a strong positive influence of the presence of epicormics. the aims of this study were, first, to make a general quantification of the epicormics present along beech stems and, secondly, to test the effects of ...201222887022
effect of tree size and competition on tension wood production over time in beech plantations and assessing relative gravitropic response with a biomechanical model.gravitropic movements are unexpected mechanical processes that could disturb tree design allometries derived from the physics of nonliving bodies. we investigated whether the scaling law of gravitropic performance (power of -2 of stem diameter) derived from integrative biomechanical modeling is disturbed by ontogeny or environment, then discuss the silvicultural and dendroecological consequences.201222922395
the composition of phyllosphere fungal assemblages of european beech (fagus sylvatica) varies significantly along an elevation gradient.little is known about the potential effect of climate warming on phyllosphere fungi, despite their important impact on the dynamics and diversity of plant communities. the structure of phyllosphere fungal assemblages along elevation gradients may provide information about this potential effect, because elevation gradients correspond to temperature gradients over short geographic distances. we thus investigated variations in the composition of fungal assemblages inhabiting the phyllosphere of eur ...201222934891
ground-level ozone differentially affects nitrogen acquisition and allocation in mature european beech (fagus sylvatica) and norway spruce (picea abies) trees.impacts of elevated ground-level ozone (o(3)) on nitrogen (n) uptake and allocation were studied on mature european beech (fagus sylvatica l.) and norway spruce (picea abies [l.] karst.) in a forest stand, hypothesizing that: (i) chronically elevated o(3) limits nutrient uptake, and (ii) beech responds more sensitively to elevated o(3) than spruce, as previously found for juvenile trees. tree canopies were exposed to twice-ambient o(3) concentrations (2 × o(3)) by a free-air fumigation system, w ...201223042769
resistance of european tree species to drought stress in mixed versus pure forests: evidence of stress release by inter-specific facilitation.while previous studies focused on tree growth in pure stands, we reveal that tree resistance and resilience to drought stress can be modified distinctly through species mixing. our study is based on tree ring measurement on cores from increment boring of 559 trees of norway spruce (picea abies [l.] karst.), european beech (fagus sylvatica [l.]) and sessile oak (quercus petraea (matt.) liebl.) in south germany, with half sampled in pure, respectively, mixed stands. indices for resistance, recover ...201323062025
assessing ozone and nitrogen impact on net primary productivity with a generalised non-linear model.some studies suggest that in europe the majority of forest growth increment can be accounted for n deposition and very little by elevated co(2). high ozone (o(3)) concentrations cause reductions in carbon fixation in native plants by offsetting the effects of elevated co(2) or n deposition. the cause-effect relationships between primary productivity (npp) of quercus cerris, q. ilex and fagus sylvatica plant species and climate and pollutants (o(3) and n deposition) in italy have been investigate ...201323078996
differences in soil fungal communities between european beech (fagus sylvatica l.) dominated forests are related to soil and understory vegetation.fungi are important members of soil microbial communities with a crucial role in biogeochemical processes. although soil fungi are known to be highly diverse, little is known about factors influencing variations in their diversity and community structure among forests dominated by the same tree species but spread over different regions and under different managements. we analyzed the soil fungal diversity and community composition of managed and unmanaged european beech dominated forests located ...201223094057
effect of elevated carbon dioxide concentration on carbon assimilation under fluctuating light.natural fluctuations in light intensity may significantly affect the amount of co assimilated by plants and ecosystems. little is known, however, about the interactive effect of dynamic light conditions and atmospheric co concentrations. the hypothesis that elevated co concentration (ec; 700 μmol co mol) increases photosynthetic efficiency in dynamic light environments as compared to ambient co concentration (ac; 385 μmol co mol) was tested. sun leaves of european beech ( l.) and current-year sh ...201323128750
hitchhiking with forests: population genetics of the epiphytic lichen lobaria pulmonaria in primeval and managed forests in southeastern europe.availability of suitable trees is a primary determinant of range contractions and expansions of epiphytic species. however, switches between carrier tree species may blur co-phylogeographic patterns. we identified glacial refugia in southeastern europe for the tree-colonizing lichen lobaria pulmonaria, studied the importance of primeval forest reserves for the conservation of genetically diverse populations and analyzed differences in spatial genetic structure between primeval and managed forest ...201223139881
fruit production in three masting tree species does not rely on stored carbon reserves.fruiting is typically considered to massively burden the seasonal carbon budget of trees. the cost of reproduction has therefore been suggested as a proximate factor explaining observed mast-fruiting patterns. here, we used a large-scale, continuous (13)c labeling of mature, deciduous trees in a temperate swiss forest to investigate to what extent fruit formation in three species with masting reproduction behavior (carpinus betulus, fagus sylvatica, quercus petraea) relies on the import of store ...201323306421
gap dynamics and structure of two old-growth beech forest remnants in slovenia.due to a long history of intensive forest exploitation, few european beech (fagus sylvatica l.) old-growth forests have been preserved in europe.201323308115
allergen of the month--european beech. 201323352543
elevated co2 enrichment induces a differential biomass response in a mixed species temperate forest plantation.in a free-air carbon dioxide (co(2)) enrichment study (bangorface), alnus glutinosa, betula pendula and fagus sylvatica were planted in areas of one-, two- and three-species mixtures (n = 4). the trees were exposed to ambient or elevated co(2) (580 μmol mol(-1)) for 4 yr, and aboveground growth characteristics were measured. in monoculture, the mean effect of co(2) enrichment on aboveground woody biomass was + 29, + 22 and + 16% for a. glutinosa, f. sylvatica and b. pendula, respectively. when t ...201323356474
assessment of spatial discordance of primary and effective seed dispersal of european beech (fagus sylvatica l.) by ecological and genetic methods.spatial discordance between primary and effective dispersal in plant populations indicates that postdispersal processes erase the seed rain signal in recruitment patterns. five different models were used to test the spatial concordance of the primary and effective dispersal patterns in a european beech (fagus sylvatica) population from central spain. an ecological method was based on classical inverse modelling (sss), using the number of seed/seedlings as input data. genetic models were based on ...201323379310
current near-to-nature forest management effects on functional trait composition of saproxylic beetles in beech forests.with the aim of wood production with negligible negative effects on biodiversity and ecosystem processes, a silvicultural practice of selective logging with natural regeneration has been implemented in european beech forests (fagus sylvatica) during the last decades. despite this near-to-nature strategy, species richness of various taxa is lower in these forests than in unmanaged forests. to develop guidelines to minimize the fundamental weaknesses in the current practice, we linked functional t ...201323432190
odor, gaseous and pm10 emissions from small scale combustion of wood types indigenous to central europe.in this study, we investigated the emissions, including odor, from log wood stoves, burning wood types indigenous to mid-european countries such as austria, czech republic, hungary, slovak republic, slovenia, switzerland, as well as baden-württemberg and bavaria (germany) and south tyrol (italy). the investigations were performed with a modern, certified, 8 kw, manually fired log wood stove, and the results were compared to emissions from a modern 9 kw pellet stove. the examined wood types were ...201223471123
tree species diversity interacts with elevated co2 to induce a greater root system response.as a consequence of land-use change and the burning of fossil fuels, atmospheric concentrations of co2 are increasing and altering the dynamics of the carbon cycle in forest ecosystems. in a number of studies using single tree species, fine root biomass has been shown to be strongly increased by elevated co2 . however, natural forests are often intimate mixtures of a number of co-occurring species. to investigate the interaction between tree mixture and elevated co2 , alnus glutinosa, betula pen ...201223504733
effects of drought on mesophyll conductance and photosynthetic limitations at different tree canopy layers.in recent years, many studies have focused on the limiting role of mesophyll conductance (gm ) to photosynthesis (an ) under water stress, but no studies have examined the effect of drought on gm through the forest canopy. we investigated limitations to an on leaves at different heights in a mixed adult stand of sessile oak (quercus petraea) and beech (fagus sylvatica) trees during a moderately dry summer. moderate drought decreased an of top and lowest beech canopy leaves much more than in leav ...201323527762
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