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Sample records for beech trees

  1. Evaluation of digital photography for quantifying Cryptococcus fagisuga (Hemiptera: Eriococcidae) density on American beech trees.

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    Wieferich, D J; Hayes, D B; McCullough, D G

    2013-06-01

    Beech scale (Cryptococcus fagisuga Lindinger) (Hemiptera: Eriococcidae) is an invasive forest insect established in the eastern United States and Canada. It predisposes American beech (Fagus grandifolia Ehrhart) trees to infection by Neonectria spp. Fungi causing beech bark disease. White wax secreted by the diminutive scales obscures individual insects, making it difficult to accurately quantify beech scale density. Our goals were to 1) evaluate the relationship between the area of wax and number of beech scales on bark samples, 2) determine whether digital photos of bark could accurately quantify beech scale density, and 3) compare efficiency and utility of a qualitative visual estimate and using the quantitative digital photo technique to assess beech scale populations. We visually estimated beech scale abundance and photographed designated areas on the trunk of 427 trees in 40 sites across Michigan. Photos were analyzed using a binary threshold technique to quantify the area of beech scale wax on each photo. We also photographed and then collected 104 bark samples from 45 additional beech trees in ten sites. We removed the wax, counted individual scales on each sample using a microscope, and assessed the linear relationship between wax area and scale counts. Area of wax explained approximately 80% of the variability in scale density. We could typically quantify beech scale density on 15 photographs per hour. Qualitative visual assessments of beech scale in the field corresponded with estimates derived from photos of bark samples for 79% of trees.

  2. Beech vs. Pine - how different tree species manage their water demands

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    Heidbüchel, Ingo; Dreibrodt, Janek; Simard, Sonia; Güntner, Andreas; Blume, Theresa

    2016-04-01

    In north-eastern Germany large parts of the landscape are covered by pine trees. Although beech used to be one of the typical species for the region, today it makes up only a small fraction of the forested area. In order to reinstate a more natural forest composition an effort is made to decrease the coniferous forest in the next 30 years from 70% to 40% while increasing the deciduous forest from 20% to 40%. This will have consequences for the forest water balance that we would like to understand better. In an attempt to capture the complete tree water balance for both species we monitored all relevant hydrologic fluxes in four stands of pure beech and pine (both young and old stands) as well as in eight mixed stands (as part of the TERENO observatory). Extensive measurements of throughfall and stemflow were conducted with 35 rain trough systems, 50 stemflow collectors and tipping buckets. Soil moisture was monitored in 70 depth profiles with a total of 450 sensors ranging from 10 cm down to 200 cm. In combination with soil water potential measurements at 5 depths root water uptake from different depths and hydraulic redistribution between depths could be determined. Sapflux sensors recorded tree water use for 16 trees and groundwater level was monitored at 16 locations. We found that soil moisture conditions under beech were more variable than under pine, especially in the upper 100 cm. This was due to the higher influx of water from stemflow on the one hand and to the more intensive/effective use of soil water by the beech on the other hand. Our sap flux measurements show that beech was able to sustain steady rates of sapflux even under extremely dry soil conditions. While annual average sapflow was twice as high for pines compared to beeches, pine trees were less effective in taking up water from the soil and reduced sap flow considerably during dry phases. We still found the upper 100 cm of soil under pine to be generally wetter than under beech and considered

  3. Tree development and productivity of beech coppice stands in the Crni Vrh region

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    Pantić Damjan

    2003-01-01

    Full Text Available The trends of development and increment of individual trees, as well as the productivity of beech coppice stands in the region of Crni Vrh were studied. The trees in the category of 20% of the largest-diameter trees in the stand were analyzed by the standard dendrometric analysis, the productivity was assessed based on the values of the major taxation elements measured at the sample plots. The results of these analyses, combined with the results reported by other authors, who studied beech coppice forests at the same locality but from different aspects, enable the real and comprehensive assessment of the state of these stands. On this basis, the aim of long-term management (conversion into a high silvicultural form and the actual silvicultural measure (high selection thinning were defined.

  4. Parametric identification of a functional-structural tree growth model and application to beech trees (Fagus sylvatica)

    CERN Document Server

    Letort, Veronique; Mathieu, Amélie; De Reffye, Philippe; Constant, Thiéry

    2010-01-01

    Functional-structural models provide detailed representations of tree growth and their application to forestry seems full of prospects. However, owing to the complexity of tree architecture, parametric identification of such models remains a critical issue. We present the GreenLab approach for modelling tree growth. It simulates tree growth plasticity in response to changes of their internal level of trophic competition, especially topological development and cambial growth. The model includes a simplified representation of tree architecture, based on a species-specific description of branching patterns. We study whether those simplifications allow enough flexibility to reproduce with the same set of parameters the growth of two observed understorey beech trees (Fagus sylvatica L.) of different ages in different environmental conditions. The parametric identification of the model is global, i.e. all parameters are estimated simultaneously, potentially providing a better description of interactions between sub...

  5. A double-entry tree volume table for beech (Fagus sylvatica L. coppices in Piedmont

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    Nosenzo A

    2008-09-01

    Full Text Available The aim of the present work is to fill a gap in the collection of available algorithms for the estimation of standing tree volume. The deficiency of such tools is especially marked when their object is represented by stands undergoing strong or rapid changes in forest structure. Such is the case of beech (Fagus sylvatica L. coppices in Piedmont, once managed mainly for firewood, i.e., with fast rotations and a mean tree size much smaller than what observed in current stands. In addition, the structure of most of these stands was heavily impacted by selection cuttings in the early '90s, aimed at the conversion of coppices to high forests in the long run. A single tree volume table (inclusive of branches and bark volumes has been prepared according to the following steps: (1 selection of relevant stands, representative in their extent, density and merchantability (13 alpine valleys in 6 provinces; (2 computation of sample size according to the observed variability in the selected study areas (1085 model trees for height and volume; (3 tree measurement and data mining (statistical detection of outliers and selection of the most suitable model form for a double-entry tree volume table. The main output of the study is the volume table itself. The paramount importance of such tool for forest management is confirmed by the abundance of beech forests (136000 hectares, i.e., the second most represented forest cover type in the study region, 90% of which is still managed as coppice stands.

  6. Over-mature beech trees (Fagus orientalis Lipsky) and close-to-nature forestry in northern Iran

    Institute of Scientific and Technical Information of China (English)

    Mostafa Moradi; Mohammad R.Marvie Mohadjer; Kiomars Sefidi; Mahmoud Zobiri; Ali Omidi

    2012-01-01

    Oriental Beech is the most important commercial tree species in northern Iran.In recent years wood production companies interested in felling large beech trees for profit have challenged advocates of close-to-nature silviculture who favor conservation.Our study objective was to assess the economic value of over-mature beech trees by relating tree diameter (DBH) to amount of decay.Based on the location of onset of decay,we categorized three types of decay as stump,stem,and crown decay.Trees of greater diameter (age) typically showed greater decay in the stem.Percent of decayed volume,diameter of decayed tissue,and length of decay in tree stems varied between 0.5%-64.3%,15 cm-75 cm,and 2.0-19.5 m,respectively.With increasing trunk diameter,the proportion of truck decay increased.Red heart and dark red heart constituted 25% and 14.3% of sampled trees,respectively.However,we found no correlation between intensity of stem decay and morphological characteristics of trees.Seedlings were not abundant around the bases of over-mature trees,suggesting that the trees did not contribute to regeneration of the stand.Beech trees of diameter >1 m do not provide valuable round wood for industries and cause to raise wood production costs.We recommend that these trees >1 m DBH should be retained in forest stands because of their low commercial value but high ecological and conservational values such as maintaining biodiversity in forest ecosystems.

  7. DECLINE IN SOIL CO2 EFFLUX FOLLOWING TREE GIRTLING IN MATURE BEECH AND SPRUCE STANDS IN GERMANY

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    Studies were undertaken to estimate the contribution of autotrophic respiration to total soil CO2 efflux in stands of mature European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Five mature trees of each species were girdled to eliminate carbo...

  8. Sensitivity of European beech trees to unfavorable environmental factors on the edge and outside of their distribution range in northeastern Europe

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    Augustaitis A

    2016-04-01

    Full Text Available European beech is a successful tree species outside its distribution range in northeastern Europe, where Prussian foresters introduced it mainly into Scots pine stands. This forest management practice resulted in new issues related to the sensitivity of European beech to current environmental changes in areas outside its natural range. We hypothesized that recent global environmental changes promoted the northeast migration of European beech outside its distribution range in Europe. To test this hypothesis, dendrochronological analysis of beech tree ring series was performed for eight sites located in Poland, Lithuania and Latvia. Frost in winter months and heat in June, along with drought in the vegetation period, limited beech tree growth outside its natural distribution range in northeast Europe. Higher air concentration of surface ozone and sulphur deposition level reinforced the negative effect of the detected key meteorological variables on beech growth, while higher air concentrations and deposition of nitrate had a positive effect. These factors explained about 50% of the total variation in increment indexes of beech trees at sites on the northeasren edge of their range. The observed trends of beech growth over the last 25 years has determined favorable conditions for planting this tree species outside its natural range in northeastern European forests.

  9. Tree biomass and deadwood density into aged holm oak (Sardinia and beech coppices (Tuscany

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    Bertini G

    2012-05-01

    Full Text Available Current National Forest Inventory highlight the further increase over the last two decades of coppice area under the position of mature standing crop or in the post-cultivation phase, both being developed throughout the original cultivation area. This pattern, mainly due to the unprofitable fuel wood harvesting, also involved holm oak and beech forests, some of the most diffused forest covers in Sardinia, along the Apennines and pre-Alps. The alternative management option to ageing (the pro-active way of coppice conversion into high forest has been also practiced in the public domain, but on much smaller areas as compared with those undergoing post-cultivation phase. Aged coppices located into medium-good site classes showed a positive growth pattern resulting in a high, age-related, wood matter storage. At the meantime, regular mortality occurring since former rotation into the fully-stocked shoot populations, stocked up high deadwood amounts, this becoming an outstanding attribute of these types. Carbon storage is becoming one of the major tasks attributable to these systems within the post-cultivation phase. Purposes are here to: (i estimate living woody and standing + lying deadwood mass densities; (ii determine deadwood/living mass ratio; (iii verify lying deadwood decay class; (iv analyse diversity between two sites aged likewise but different as for geographical location and tree species. A holm oak coppice aged 55 in Sardinia and a beech coppice aged 57 in Tuscany were selected at the purpose. Both stands have been developing the post-cultivation phase since two-three times the traditional rotation and represent the maximum ages in this position. Living and standing dead woody dry mass density were determined in each site by specific allometric functions. Lying deadwood amount was assessed by a sampling design covering systematically the full test area. Three decay classes were determined according to Hunter (modified. The tree species

  10. Changes in the Community of Ectomycorrhizal Fungi and Increased Fine Root Number Under Adult Beech Trees Chronically Fumigated with Double Ambient Ozone Concentration

    OpenAIRE

    Grebenc, Tine; Kraigher, Hojka

    2007-01-01

    Forest soils are an important but under-studied part of forest ecosystems. The effects of O3 on below-ground processes in a mature forest have only received limited attention so far. In our study, we have analysed the community of ectomycorrhizal fungi and beech fine root dynamics over two growing seasons (2003–2004) in a 70-year old mixed spruce-beech forest stand, in which two groups of five adult beech trees were either fumigated by 2 × ambient ozone concentration or used as control. The m...

  11. The amount and quality of dead trees in a mixed beech forest with different management histories in northern Iran

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    KIOMARS SEFIDI

    2014-10-01

    Full Text Available Sefidi K, Etemad V. 2014. The amount and quality of dead trees in a mixed beech forest with different management histories in northern Iran. Biodiversitas 15: 162-168. Dead tree (fallen logs and snags, is regarded as an important ecological component of forests on which many forest dwelling species depend, yet its relation to management history in Caspian forest has gone unreported. The aim of research aim was to compare the amounts of dead tree in the forests with historically different intensities of management, including: forests with the long term implication of management (Patom, the short term implication of management (Namekhaneh which were compared with semi virgin forest (Gorazbon. The number of 215 individual dead trees were recorded and measured at 79 sampling locations. ANOVA revealed volume of dead tree in the form and decay classes significantly differ within sites and dead volume in the semi virgin forest significantly higher than managed sites. Comparing the amount of dead tree in three sites showed that, dead tree volume related with management history and significantly differ in three study sites. Reaching their highest in virgin site and their lowest in the site with the long term implication of management, it was concluded that forest management cause reduction of the amount of dead tree. Forest management history affect the forest's ability to generate dead tree specially in a large size, thus managing this forest according to ecological sustainable principles require a commitment to maintaining stand structure that allow, continued generation of dead tree in a full range of size.

  12. Canopy recovery of pedunculate oak, Turkey oak and beech trees after severe defoliation by gypsy moth (Lymantria dispar): Case study from Western Hungary

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    Csóka György; Pödör Zoltán; Nagy Gyula; Hirka Anikó

    2015-01-01

    We investigated the canopy recovery of 3 tree species (pedunculate oak, Turkey oak, European beech) at two locations in the Veszprém county (Western Hungary) after severe defoliation by gypsy moth caterpillars in the spring of 2005. The Turkey oak has evidently the best recovery potential, and it almost completely replaced the lost foliage in 4 months. The pedunculate oak and beech needed 2 years to reach the same level of recovery. The pedunculate oak suffered from a heavy infection of Micro...

  13. Beech tree analyses in the Bohemian/Austrian/Bavarian frontier region; Fallstudie Buche im Dreilaendereck Boehmen/Oberoesterreich/Bayern

    Energy Technology Data Exchange (ETDEWEB)

    Kirchner, M. [GSF - Forschungszentrum fuer Umwelt und Gesundheit GmbH, Muenchen (Germany). Inst. fuer Oekologische Chemie; Baumgarten, M.; Matyssek, R. [Muenchen Univ., Freising (DE). Lehrstuhl fuer Forstbotanik] [and others

    2000-08-01

    The condition of beech trees was investigated in six forest stands in the Bayerischer Wald and Boehmerwald mountains between 1995 and 1997 in order to establish the interdependence between tree conditions, the prevailing natural and anthropogenic site factors, and air pollution especially with groundlevel ozone. Details of the investigations are presented. Although a potential long-term effect of ozone cannot be excluded, the damage observed in beech trees in this region since the eighties is assumed to be caused not by a single factor but by complex interaction patterns between several anthropogenic and natural factors. [German] Es erfolgte im Untersuchungsgebiet Bayerischer Wald/Boehmerwald im Zeitraum 1995 bis 1997 eine detaillierte Zustandscharakterisierung von Altbuchen an sechs Standorten. Im Rahmen der Gesamtuntersuchung sollte geklaert werden, ob Zusammenhaenge zwischen dem Baumzustand und den herrschenden natuerlichen und anthropogenen Standortfaktoren und Luftbelastungen mit Schwerpunkt des bodennahen Ozons bestehen. An Hand kontinuierlicher Ozonmessungen konnte bestaetigt werden, dass die Konzentration des bodennahen Ozons im wesentlichen eine Funktion der Meereshoehe ist; somit ist an Hochlagenstandorten von hoeheren Immissionen auszugehen. Bei den moeglicherweise besser an photooxidativen Stress akklimatisierten Hochlagenbuchen waren die Schaeden bei erhoehter Ozonbelastung geringer ausgepraegt als bei Tieflagenbuchen. Fuer die Hypothese, wonach man eine staerkere Schaedigung der Hochlagenbestaende zu erwarten hat, wurde keine Bestaetigung gefunden. Inositol wird seit einiger Zeit als sensitiver Indikator diskutiert, der auf veraenderte Umweltbedingungen reagiert. Die Inositolkonzentration in Sonnenblaettern von Altbuchen im Bayerischen Wald war in 1995 um ca. 50% geringer als in 1996. Bei den Jungbuchen im Phytotronenexperiment kam es bei anhaltendem Ozonstress und zunehmender Schaedigung zu einer starken Reduktion der Inositolkonzentration in

  14. Form of beech trees in coppice forests of Fruška Gora

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    Banković Staniša

    2004-01-01

    Full Text Available The study of tree form - form factors and form quotients and their interrelationship and the relation with other elements of volume is a necessary precondition for the construction of volume tables by the increasingly applied indirect methods. After the magnitudes of these parameters of tree form were defined, we studied the correlation between normal form quotients and normal form factor, between normal form factor and tree diameter and height, and between normal form factor and artificial form factor.

  15. Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach.

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    Genet, H; Bréda, N; Dufrêne, E

    2010-02-01

    Two types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root:shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m(-)(2) year(-1) at 30 years old to 129 gC m(-2) year(-1) at 138 years old. In beech, carbon allocation to storage and

  16. Occurrence of tannins in leaves of beech trees (Fagus sylvatica) along an ecological gradient, detected by histochemical and ultrastructural analyses

    International Nuclear Information System (INIS)

    Sclerophylly and synthesis of phenolic compounds are active responses of plants subjected to environmental stress (drought, low nutrient supply, u.v.-B radiation, ozone). Here we describe the morphological and histochemical alterations occurring in field-grown leaves of Fagus sylvatica L. from three sites located along an ecological gradient: from a site in cool and protected conditions to one located on a mountain ridge, where the trees grow on a thin layer of soil and are exposed to the wind and to intense solar radiation in summer. The morphological data show that, as the ecological conditions of the stand worsen, individual leaf surface decreases, while the thickness of the leaves and their specific d. wt (i.e. d. wt per unit leaf area) increases. Histochemical and ultrastructural tests show a marked increase of phenolics during the course of the year. These substances, present primarily in the leaves of trees growing in stress conditions, have been identified mainly as tannins. They accumulate in the vacuoles, especially those of the upper epidermal layer and the palisade mesophyll; at a later stage they appear to be solubilized in the cytoplasm and retranslocated, eventually impregnating the outer wall of the epidermal cells amidst the cellulose fibrils, where they cluster together and form an electron-opaque layer between the wall and the cuticle. Observation of the epidermal cells also reveals that the outer cell wall is thicker. The paper discusses the roles of secondary metabolites in protection and detoxification processes; the possible ecological significance of these alterations in the ecophysiology of beech trees. (author)

  17. Canopy recovery of pedunculate oak, Turkey oak and beech trees after severe defoliation by gypsy moth (Lymantria dispar: Case study from Western Hungary

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    Csóka György

    2015-09-01

    Full Text Available We investigated the canopy recovery of 3 tree species (pedunculate oak, Turkey oak, European beech at two locations in the Veszprém county (Western Hungary after severe defoliation by gypsy moth caterpillars in the spring of 2005. The Turkey oak has evidently the best recovery potential, and it almost completely replaced the lost foliage in 4 months. The pedunculate oak and beech needed 2 years to reach the same level of recovery. The pedunculate oak suffered from a heavy infection of Microsphaera alphitoides after defoliation and it probably slowed down its recovery. Neither the presence of Agrilus biguttatus in the oak plot nor the appearance of Agrilus viridis in the beech plot was observed during the study period. Population density of the buprestid Coraebus floerentinus showed a considerable increase in the oak plot, but remained under the damage level. Neither other harmful appearance of other pests nor significant tree mortality were observed within 4 years from the defoliation. These results provide information for the evaluation of longer term influences of the gypsy moth defoliation and may support the decisions concerning pest control.

  18. Ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus Apiognomonia errabunda of adult European beech trees

    International Nuclear Information System (INIS)

    In 2006, a controlled infection study was performed in the 'Kranzberger Forst' to address the following questions: (1) Will massive artificial inoculation with Apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) Can biochemical or molecular markers be detected to account for the action of ozone? To this end six adult beech trees were chosen, three ozone fumigated (2x ozone) and three control trees (ambient = 1x ozone). Spore-sprayed branches of sun and shade crown positions of each of the trees, and uninoculated control branches, were enclosed in 100-L plastic bags for one night to facilitate infection initiation. Samples were taken within a five-week period after inoculation. A. errabunda infestation levels quantified by real-time PCR increased in leaves that were not fumigated with additional ozone. Cell wall components and ACC (ethylene precursor 1-amino cyclopropane-1-carboxylic acid) increased upon ozone fumigation and may in part lead to the repression of fungal infection. - Chronic sublethal ozone exposure reduces both natural and artificial infestation of beech leaves by the endophytic fungus Apiognomonia errabunda.

  19. Long-term effects of gap creation and liming on understory vegetation with a focus on tree regeneration in a European beech (Fagus sylvatica L. forest

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    N. Lin

    2014-12-01

    Full Text Available The long-term effects of gap creation and liming on tree regeneration and understory competition were examined in a mature European beech (Fagus sylvatica stand on a nutrient-poor site. In 1989, trees were felled to create four 30 m wide circular gaps, and 3 t ha-1 fine dolomite was applied to two of these gaps and the surrounding area, whereas the remaining two gaps and most parts of the stand remained untreated. In 2010, the stand density was 153 trees x ha-1 and the basal area was 29.51 m2 x ha-1. Testing a factorial combination of two levels of canopy cover (gap and stand and two levels of lime application (limed and unlimed, the results of the case study partly support our initial hypothesis that the combined or single effects of liming and canopy removal on understory plant communities last for more than 20 years. Some effects disappeared slowly over time, while others did not. Understory vegetation of the unlimed gaps and thelimed and unlimed stands was rapidly dominated by beech regeneration, whereas limed gaps were dominated by fireweed (Epilobium angustifolium, bramble (Rubus fruticosus agg. and raspberry (Rubus ideaus for around 14 years. There, the density of the beech regeneration was reduced by competitive ground vegetation species. Plant species richness (n/100 m² was still significantly different after 23 years, with an average 10 species per 100 m² in the limed stand area, 5 species in the unlimed stand area, 25 species in the limed gaps, and only 5 species in the unlimed gaps. Only the combination of liming and canopy removal enhanced the species richness in the long run. On our study site, this combination of liming and canopy opening had a long lasting influence on the ground vegetation in terms of retarding the beech regeneration and enhancing species’ richness.

  20. Beech trees exposed to high CO{sub 2} and to simulated summer ozone levels: Effects on photosynthesis, chloroplast components and leaf enzyme activity

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, C. [Univ. of Innsbruck, Inst. of Botany, Innsbruck (Austria); Anegg, S. [GFS. National Research Centre for Environment and Health, Inst. of Biochemical Plant Pathology, Oberschleissheim (Germany); Gerant, D.; Dizengremel, P. [Univ. Henri Poincare Nancy 1, Lab. de Biologie Forestiere, Vandauvre les Nancy cedex (France); Alaoui-Sosse, B. [Lab. de Biologie et Ecophysiologie, Besancon cedex (France)

    2000-07-01

    Young trees of European beech (Fagus sylvatica L.) were exposed in a phytotron to different levels of ozone and CO{sub 2} under the climatic simulation of one vegetation period. High ozone levels were simulated similar to high ozone concentration in the field (up to 110 ppb), while CO{sub 2} was added as 300 ppm to the present level of ca 380 ppm. Our study describes different aspects of photosynthesis from the leaf level to the reactions of selected thylakoid components at different harvest times during growth of the beech trees under the different fumigation regimes. Ozone effects appeared in the first weeks of the treatment as a stimulation of chlorophyll fluorescence (F{sub v}/F{sub m}), in oxygen production and in ribulose-1,5-bisphosphate carboxylase/oxygenase activity, while the summer and early autumn harvests showed strong reductions in these parameters. Only phosphoenolpyruvate carboxylase (PEPcase) activity remained higher under high ozone. The effects of high CO{sub 2} appeared in general as a small stimulation in enzyme activity like PEPcase in spring. However, with increasing time of fumigation, reductions of all parameters were observed. Especially chlorophylls showed strong reductions under high CO{sub 2}. The combined treatment with high ozone plus high CO{sub 2} resulted mostly in an amelioration of the negative ozone effects, although control levels were not reached. (au)

  1. Biomass equations for European beech growing on dry sites

    OpenAIRE

    Chakraborty T; Saha S; Reif A

    2016-01-01

    Biomass equations for European beech (Fagus sylvatica L.) trees growing on dry sites have not been published, although such equations are needed for a proper estimation of the biomass of beech trees growing naturally at their drought limit in dry forests. We aimed to: (1) develop new allometric above-ground biomass equations for European beech trees growing on dry sites; (2) compare these equations with existing biomass equations. We harvested 86 plants, ranging from saplings to trees, from f...

  2. Ecology of beech forests in the northern hemisphere.

    NARCIS (Netherlands)

    Peters, R.

    1992-01-01

    Beech forests are dominated or codominated by at least one Fagus species. The beeches are a homogeneous group of 11 deciduous tree species growing in the Northern Hemisphere (Figure 1.1). They often dominate forest ecosystems throughout their ranges. The optimum for beech is on acidic and mesic loam

  3. Effects of thinning on stand structure and tree stability in an afforested oriental beech (Fagus orientalis Lipsky) stand in northeast Turkey

    Institute of Scientific and Technical Information of China (English)

    Zafer Yucesan; Sevilay O zc¸elik; Ercan Oktan

    2015-01-01

    We studied relationships between stand structure and stand stability according to thinning intensity in an afforested oriental beech stand. Various thinning intensities were applied in sample stands. We sampled eight plots in stands that were lightly thinned, eight plots in heavily thinned stands and eight plots in unthinned stands as a control. Height and diameter distributions of the stands were measured to assess stand structure. We quantified individual tree stability and collective stability. Heavy thinning during the first thin-ning operation damaged the storied structure of the stand in thicket stage and affected collective structuring ability. While most control plots had multi-storied stands, after light and heavy thinning two-storied structure became more common. Large gaps occurred in the canopy after heavy thinning. On average, nine tree collectives were formed per sampling plot in the untreated stand, seven collectives after thinning in 2008 and four collectives after thinning in 2009. Stable trees accounted for 17%of trees in control plots, 24%in lightly thinned plots, and 15%in heavily thinned plots. Collective stability values were 83%in control plots, 82%in lightly thinned plots and 36%in heavily thinned plots. We conclude that it is necessary to retain collective structuring capacity during thinning operations for sustaining stand stability.

  4. Subcellular nutrient element localization and enrichment in ecto- and arbuscular mycorrhizas of field-grown beech and ash trees indicate functional differences.

    Directory of Open Access Journals (Sweden)

    Jasmin Seven

    Full Text Available Mycorrhizas are the chief organ for plant mineral nutrient acquisition. In temperate, mixed forests, ash roots (Fraxinus excelsior are colonized by arbuscular mycorrhizal fungi (AM and beech roots (Fagus sylvatica by ectomycorrhizal fungi (EcM. Knowledge on the functions of different mycorrhizal species that coexist in the same environment is scarce. The concentrations of nutrient elements in plant and fungal cells can inform on nutrient accessibility and interspecific differences of mycorrhizal life forms. Here, we hypothesized that mycorrhizal fungal species exhibit interspecific differences in mineral nutrient concentrations and that the differences correlate with the mineral nutrient concentrations of their associated root cells. Abundant mycorrhizal fungal species of mature beech and ash trees in a long-term undisturbed forest ecosystem were the EcM Lactarius subdulcis, Clavulina cristata and Cenococcum geophilum and the AM Glomus sp. Mineral nutrient subcellular localization and quantities of the mycorrhizas were analysed after non-aqueous sample preparation by electron dispersive X-ray transmission electron microscopy. Cenococcum geophilum contained the highest sulphur, Clavulina cristata the highest calcium levels, and Glomus, in which cations and P were generally high, exhibited the highest potassium levels. Lactarius subdulcis-associated root cells contained the highest phosphorus levels. The root cell concentrations of K, Mg and P were unrelated to those of the associated fungal structures, whereas S and Ca showed significant correlations between fungal and plant concentrations of those elements. Our results support profound interspecific differences for mineral nutrient acquisition among mycorrhizas formed by different fungal taxa. The lack of correlation between some plant and fungal nutrient element concentrations may reflect different retention of mineral nutrients in the fungal part of the symbiosis. High mineral concentrations

  5. Povezave med kakovostjo bukovih dreves in iz njih izdelanih sortimentov: Links between beech tree quality and assortments made of them:

    OpenAIRE

    Marenče, Jurij; Šega, Bogdan

    2015-01-01

    In our research we dealt with the standing tree, estimation of the standing tree, evaluation of its quality and evaluation of quality of assortments made of it. Thereby we critically discussed diverse criteria, currently used in the practice - the five-grade scale for standing tree evaluation, used on permanent sampling plots, and current standards for evaluating the quality of the produced assortments. On the basis of a small analyzed sample of the evaluated and afterwards felled trees we we...

  6. The effect of single-tree selction system on soil properties in an oriental beech stand of Hyrcanian forest, north of Iran

    Institute of Scientific and Technical Information of China (English)

    Kambiz Abrari Vajari; Hamid Jalilvand; Mohammad Reza Pourmajidian; Kambiz Espahbodi; Alireza Moshki

    2011-01-01

    A case study was conducted in beech forests of northern Iran to determine the effect of the created gaps on some soil properties in beech stand.Changes of soil properties in small (60-150 m2),medium (151-241 m2),large (242-332 m2) and very large (333-550 m2) gaps,as well as under closed stands were studied eight years after·the gap creation.Soil samples were taken from three depths,0-10,10-20 and 20-30 cm.The gaps were different from their around undisturbed stands in terms of the following soil parameters:Mg+2 concentration of 0-10 cm at medium gap size,bulk density of 10-20 cm at very large gap size as well as K+ and Ca+2 concentrations at 20-30 cm at small and large gap sizes,respectively.Furthermore,the size of the gaps had no effect on soil characteristics through the whole profile.Water saturation percent (Sp %) at 0-10cm as well as P and Mg+2 at 20-30 cm was different amongst undisturbed stands around different gap sizes.The center and the edges of the gap were different only in terms of organic carbon at the depth of 10-20 cm.Significant differences were observed between gaps and closed canopy regarding P and Ca+2 at depth 0-10 cm and 10-20 cm,respectively.It can be concluded that applied silvicultural system for harvesting trees which created these gaps might be suitable for conservation and forest management in the region.

  7. Tree ring isotopes of beech and spruce in response to short-term climate variability across Central European sites: Common and contrasting physiological mechanisms

    Science.gov (United States)

    Weigt, Rosemarie; Klesse, Stefan; Treydte, Kerstin; Frank, David; Saurer, Matthias; Siegwolf, Rolf T. W.

    2016-04-01

    The combined study of tree-ring width and stable C and O isotopes provides insight in the coherences between carbon allocation during stem growth and the preceding conditions of gas exchange and formation of photosynthates as all influenced by environmental variation. In this large-scale study comprising 10 sites across a range of climate gradients (temperature, precipitation) throughout Central Europe, we investigated tree-rings in European beech (Fagus sylvatica) and Norway spruce (Picea abies) trees. The sampling design included larger and smaller trees. The short-term, i.e. year-to-year, variability in the isotope time series over 100 yrs was analyzed in relation to tree-ring growth and climate variation. The generally strong correlation between the year-to-year differences in δ13C (corrected for the atmospheric shift due to 13C-depleted CO2 from fossil combustion) and δ18O across most sites emphasized the role of stomatal conductance in controlling leaf gas exchange. However, the correlation between both isotopes decreased during some periods. At several sites this reduction in correlation was particularly pronounced during recent decades. This suggests a decoupling between stomatal and photosynthetic responses to environmental conditions on the one hand, and carbon allocation to stem tissue on the other hand. Variability in the isotopic ratio largely responded to summer climate, but was weakly correlated to annual stem growth. In contrast, climate sensitivity of radial growth in both species was rather site-dependent, and was strongest at the driest (in terms of soil water capacity) site. We will also present results of isotope responses with respect to extreme climate events. Understanding the underlying physiological mechanisms controlling the short-term variation in tree-ring signals will help to assess and more precisely constrain the possible range of growth performance of these ecologically and economically important tree species under future climate

  8. Assessing the risk caused by ground level ozone to European forest trees: a case study in pine, beech and oak across different climate regions.

    Science.gov (United States)

    Emberson, Lisa D; Büker, Patrick; Ashmore, Mike R

    2007-06-01

    Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold of 40 ppb) and (ii) the recently developed flux based AFstY index (Accumulated stomatal Flux above a flux threshold Y). This paper compares the AOT40 and AFstY indices for three forest trees species at different locations in Europe. The AFstY index is estimated using the DO(3)SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (Pinus sylvestris), beech (Fagus sylvatica) and holm oak (Quercus ilex). The results show a large difference in the perceived O(3) risk when using AOT40 and AFstY indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFstY. There are significant differences in modelled AFstY between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O(3) risk. PMID:17412465

  9. Belowground carbon allocation by trees drives seasonal patterns of extracellular enzyme activities by altering microbial community composition in a beech forest soil.

    Science.gov (United States)

    Kaiser, Christina; Koranda, Marianne; Kitzler, Barbara; Fuchslueger, Lucia; Schnecker, Jörg; Schweiger, Peter; Rasche, Frank; Zechmeister-Boltenstern, Sophie; Sessitsch, Angela; Richter, Andreas

    2010-08-01

    *Plant seasonal cycles alter carbon (C) and nitrogen (N) availability for soil microbes, which may affect microbial community composition and thus feed back on microbial decomposition of soil organic material and plant N availability. The temporal dynamics of these plant-soil interactions are, however, unclear. *Here, we experimentally manipulated the C and N availability in a beech forest through N fertilization or tree girdling and conducted a detailed analysis of the seasonal pattern of microbial community composition and decomposition processes over 2 yr. *We found a strong relationship between microbial community composition and enzyme activities over the seasonal course. Phenoloxidase and peroxidase activities were highest during late summer, whereas cellulase and protease peaked in late autumn. Girdling, and thus loss of mycorrhiza, resulted in an increase in soil organic matter-degrading enzymes and a decrease in cellulase and protease activity. *Temporal changes in enzyme activities suggest a switch of the main substrate for decomposition between summer (soil organic matter) and autumn (plant litter). Our results indicate that ectomycorrhizal fungi are possibly involved in autumn cellulase and protease activity. Our study shows that, through belowground C allocation, trees significantly alter soil microbial communities, which may affect seasonal patterns of decomposition processes.

  10. Assessing the risk caused by ground level ozone to European forest trees: A case study in pine, beech and oak across different climate regions

    International Nuclear Information System (INIS)

    Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold of 40 ppb) and (ii) the recently developed flux based AFstY index (Accumulated stomatal Flux above a flux threshold Y). This paper compares the AOT40 and AFstY indices for three forest trees species at different locations in Europe. The AFstY index is estimated using the DO3SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (Pinus sylvestris), beech (Fagus sylvatica) and holm oak (Quercus ilex). The results show a large difference in the perceived O3 risk when using AOT40 and AFstY indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFstY. There are significant differences in modelled AFstY between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O3 risk. - A new flux-based model provides a revised assessment of risks of ozone impacts to European forests

  11. A Technique to Screen American Beech for Resistance to the Beech Scale Insect (Cryptococcus fagisuga Lind.)

    OpenAIRE

    Koch, Jennifer L.; Carey, David W.

    2014-01-01

    Beech bark disease (BBD) results in high levels of initial mortality, leaving behind survivor trees that are greatly weakened and deformed. The disease is initiated by feeding activities of the invasive beech scale insect, Cryptococcus fagisuga, which creates entry points for infection by one of the Neonectria species of fungus. Without scale infestation, there is little opportunity for fungal infection. Using scale eggs to artificially infest healthy trees in heavily BBD impacted stands demo...

  12. Influence of soil temperature on growth traits of European beech seedlings

    OpenAIRE

    Peter C Frederick; Štraus, Ines; Mrak, Tanja; Hylton, Becky; Heath, Julie; Ferlan, Mitja; Spalding, Marilyn; Železnik, Peter; Kraigher, Hojka

    2014-01-01

    European beech (Fagus sylvatica L.) is an economically and ecologically important forest tree species in Europe. Expected future temperature increases due to global climate change may significantly affect growth of beech trees and consequently influence carbon cycling in beech forests. We tested the hypothesis that soil temperature influences the growth of both belowground and aboveground parts of beech seedlings. One-year-old seedlings were transferred into rhizotrons and subjected ...

  13. The role of the organic layer for phosphorus nutrition of young beech trees (Fagus sylvatica L.) at two sites differing in soil Phosphorus availability

    Science.gov (United States)

    Hauenstein, Simon

    2016-04-01

    Simon Hauenstein1, Thomas Pütz2, and Yvonne Oelmann1, 1 Geoecology, Department of Geosciences, University of Tübingen, Tübingen, Germany 2 Agrosphere (IBG-3), Forschungszentrum Jülich, Jülich, Germany The accumulation of an organic layer in forests is linked to the ratio between litterfall rates and decomposition rates with decomposition rates being decelerated due to acidification and associated nutrient depletion with proceeding ecosystem development. Nevertheless, the nutrient pool in the organic layer might still represent an important source for Phosphorus (P) nutrition of forests on nutrient-poor soils. Our objective was to assess the importance of the organic layer to P nutrition of young beech trees at two sites differing in soil P availability. We established a mesocosm experiment including plants and soil from a Phosphorus depleted forest site on a Haplic Podzol in Lüss and a Phosphorus rich forest site on a Eutric Cambisol in Bad Brückenau either with or without the organic layer. After 1 year under outdoor conditions, we applied 33P to the pots. After 0h, 24h, 48h, 96h, 192h, 528h we destructively harvested the young beech trees (separated into leaves, branches, stems) and sampled the organic layer and mineral soil of the pots. In each soil horizon we measured concentrations of resin-extractable P, plant available P fractions and total P. We extracted the xylem sap of the whole 2-year-old trees by means of scholander pressure bomb. 33P activity was measured for every compartment in soil and plant. The applied 33P was recovered mainly in the organic layer in Lüss, whereas it was evenly distributed among organic and mineral horizons in pots of Bad Brückenau soil. Comparing pots with and without an organic layer, the specific 33P activity differed by 323% between pots with and without an organic layer present in the Lüss soil. For both sites, the presence of the organic layer increased 33P activity in xylem sap compared to the treatment without

  14. Thinning in artificially regenerated young beech stands

    Directory of Open Access Journals (Sweden)

    Novák Jiří

    2015-12-01

    Full Text Available Although beech stands are usually regenerated naturally, an area of up to 5,000 ha year−1 is artificially regenerated by beech in the Czech Republic annually. Unfortunately, these stands often showed insufficient stand density and, consequently, lower quality of stems. Therefore, thinning methods developed for naturally regenerated beech stands are applicable with difficulties. The paper evaluates the data from two thinning experiments established in young artificially regenerated beech stands located in different growing conditions. In both experiments, thinning resulted in the lower amount of salvage cut in following years. Positive effect of thinning on periodic stand basal area increment and on periodic diameter increment of dominant trees was found in the beech stand located at middle elevations. On the other hand, thinning effects in mountain conditions were negligible. Thinning focusing on future stand quality cannot be commonly applied in artificially regenerated beech stands because of their worse initial quality and lower density. However, these stands show good growth and response to thinning, hence their management can be focused on maximising beech wood production.

  15. Unraveling carbohydrate transport mechanisms in young beech trees (Fagus sylvatica f. purpurea) by 13CO2 efflux measurements from stem and soil

    Science.gov (United States)

    Thoms, Ronny; Muhr, Jan; Keitel, Claudia; Kayler, Zachary; Gavrichkova, Olga; Köhler, Michael; Gessler, Arthur; Gleixner, Gerd

    2016-04-01

    Transport mechanisms of soluble carbohydrates and diurnal CO2 efflux from tree stems and surrounding soil are well studied. However, the effect of transport carbohydrates on respiration and their interaction with storage processes is largely unknown. Therefore, we performed a set of 13CO2 pulse labeling experiments on young trees of European beech (Fagus sylvatica f. purpurea). We labeled the whole tree crowns in a closed transparent plastic chamber with 99% 13CO2 for 30 min. In one experiment, only a single branch was labeled and removed 36 hours after labeling. In all experiments, we continuously measured the 13CO2 efflux from stem, branch and soil and sampled leaf and stem material every 3 h for 2 days, followed by a daily sampling of leaves in the successive 5 days. The compound specific δ 13C value of extracted soluble carbohydrates from leaf and stem material was measured by high-performance liquid chromatography linked with an isotope ratio mass spectrometer (HPLC-IRMS). The 13CO2 signal from soil respiration occurred only few hours after labeling indicating a very high transport rate of carbohydrates from leaf to roots and to the rhizosphere. The label was continuously depleted within the next 5 days. In contrast, we observed a remarkable oscillating pattern of 13CO2 efflux from the stem with maximum 13CO2 enrichment at noon and minima at night time. This oscillation suggests that enriched carbohydrates are respired during the day, whereas in the night the enriched sugars are not respired. The observed oscillation in stem 13CO2 enrichment remained unchanged even when only single branches were labelled and cut right afterwards. Thus, storage and conversion of carbohydrates only occurred within the stem. The δ13C patterns of extracted soluble carbohydrates showed, that a transformation of transitory starch to carbohydrates and vice versa was no driver of the oscillating 13CO2 efflux from the stem. Carbohydrates might have been transported in the phloem to

  16. Observations on the slime moulds growing on the moulder beech wood

    OpenAIRE

    Wanda Stojanowska

    2014-01-01

    We have found that the most suitable substrate for slime molds developement is the wood of dicotyledoneus trees especially that of beech. This is due to its impermanency and weak resistance to biological agents. In Silesia 42 slime molds species were found to grow on beech wood. The development of Fuligo rufa and Lucogala exiguum seems to be closely connected with beech wood.

  17. Comparisons of protein profiles of beech bark disease resistant and susceptible American beech (Fagus grandifolia

    Directory of Open Access Journals (Sweden)

    Mason Mary E

    2013-01-01

    Full Text Available Abstract Background Beech bark disease is an insect-fungus complex that damages and often kills American beech trees and has major ecological and economic impacts on forests of the northeastern United States and southeastern Canadian forests. The disease begins when exotic beech scale insects feed on the bark of trees, and is followed by infection of damaged bark tissues by one of the Neonectria species of fungi. Proteomic analysis was conducted of beech bark proteins from diseased trees and healthy trees in areas heavily infested with beech bark disease. All of the diseased trees had signs of Neonectria infection such as cankers or fruiting bodies. In previous tests reported elsewhere, all of the diseased trees were demonstrated to be susceptible to the scale insect and all of the healthy trees were demonstrated to be resistant to the scale insect. Sixteen trees were sampled from eight geographically isolated stands, the sample consisting of 10 healthy (scale-resistant and 6 diseased/infested (scale-susceptible trees. Results Proteins were extracted from each tree and analysed in triplicate by isoelectric focusing followed by denaturing gel electrophoresis. Gels were stained and protein spots identified and intensity quantified, then a statistical model was fit to identify significant differences between trees. A subset of BBD differential proteins were analysed by mass spectrometry and matched to known protein sequences for identification. Identified proteins had homology to stress, insect, and pathogen related proteins in other plant systems. Protein spots significantly different in diseased and healthy trees having no stand or disease-by-stand interaction effects were identified. Conclusions Further study of these proteins should help to understand processes critical to resistance to beech bark disease and to develop biomarkers for use in tree breeding programs and for the selection of resistant trees prior to or in early stages of BBD

  18. Hypoxylon species on beech and other broadleaves

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    Milijašević Tanja

    2004-01-01

    Full Text Available Fungi in the genus Hypoxylon cause wood decay and most of them are saprophytes on dead wood or parasites of weakness. The following species in this genus were identified in this study performed at several localities in Serbia and Montenegro: H. deustum, H. fragiforme, H. nummularium, H. multiforme, H. rubiginosum and H. fuscum. Among them the most significant species is H. deustum, the fungus causing root and butt rot of standing beech trees. It was recorded from all coppice and high forests of beech. This paper presents the morphological characteristics of the recorded fungi their range, plant hosts and significance.

  19. A technique to screen American beech for resistance to the beech scale insect (Cryptococcus fagisuga Lind.).

    Science.gov (United States)

    Koch, Jennifer L; Carey, David W

    2014-01-01

    Beech bark disease (BBD) results in high levels of initial mortality, leaving behind survivor trees that are greatly weakened and deformed. The disease is initiated by feeding activities of the invasive beech scale insect, Cryptococcus fagisuga, which creates entry points for infection by one of the Neonectria species of fungus. Without scale infestation, there is little opportunity for fungal infection. Using scale eggs to artificially infest healthy trees in heavily BBD impacted stands demonstrated that these trees were resistant to the scale insect portion of the disease complex(1). Here we present a protocol that we have developed, based on the artificial infestation technique by Houston(2), which can be used to screen for scale-resistant trees in the field and in smaller potted seedlings and grafts. The identification of scale-resistant trees is an important component of management of BBD through tree improvement programs and silvicultural manipulation.

  20. Ecology and Control of Rhododendron (Rhododendron ponticum L.) in Turkish Eastern Beech (Fagus orientalis Lipsky) Forests

    OpenAIRE

    ESEN, DERYA

    2000-01-01

    Purple-flowered rhododendron (Rhododendron ponticum L.) and yellow-flowered rhododendron (R. flavum Don.) are two dominant shrub species of the eastern beech (Fagus orientalis L.) understories in the eastern and western Black Sea Region (BSR), respectively. These invasive woody species significantly reduce beech growth and can preclude tree regeneration. The ecological consequence is an aging beech overstory with little or no regeneration to replace the mature trees. Great rhododendron (R. ...

  1. Selective bark-stripping of beech, Fagus sylvatica, by free-ranging horses

    NARCIS (Netherlands)

    Kuiters, A.T.; Sluijs, van der L.A.M.; Wytema, G.A.

    2006-01-01

    Incidence and intensity of bark-stripping by horses was surveyed in stands and tree lanes of European beech (Fagus sylvatica L.) in Veluwezoom National Park, by using transects. Damage was apparent on 38% of beech trees, and 11% were seriously damaged (score 3 or more). Susceptibility to bark-stripp

  2. Differential Responses of Herbivores and Herbivory to Management in Temperate European Beech

    OpenAIRE

    Gossner, Martin M.; Pašalić, Esther; Lange, Markus; Lange, Patricia; Boch, Steffen; Hessenmöller, Dominik; Müller, Jörg; Socher, Stephanie; Fischer, Markus; Schulze, Ernst-Detlef; Weisser, Wolfgang W.

    2014-01-01

    Forest management not only affects biodiversity but also might alter ecosystem processes mediated by the organisms, i.e. herbivory the removal of plant biomass by plant-eating insects and other arthropod groups. Aiming at revealing general relationships between forest management and herbivory we investigated aboveground arthropod herbivory in 105 plots dominated by European beech in three different regions in Germany in the sun-exposed canopy of mature beech trees and on beech saplings in the...

  3. Differential responses of herbivores and herbivory to management in temperate European beech

    OpenAIRE

    Gossner, Martin M.; Esther Pašalić; Markus Lange; Patricia Lange; Steffen Boch; Dominik Hessenmöller; Jörg Müller; Socher, Stephanie A.; Markus Fischer; Ernst-Detlef Schulze; Weisser, Wolfgang W.

    2014-01-01

    Forest management not only affects biodiversity but also might alter ecosystem processes mediated by the organisms, i.e. herbivory the removal of plant biomass by plant-eating insects and other arthropod groups. Aiming at revealing general relationships between forest management and herbivory we investigated aboveground arthropod herbivory in 105 plots dominated by European beech in three different regions in Germany in the sun-exposed canopy of mature beech trees and on beech saplings in the...

  4. Seasonality and resource availability control bacterial and archaeal communities in soils of a temperate beech forest

    OpenAIRE

    Rasche, Frank; Knapp, Daniela; Kaiser, Christina; Koranda, Marianne; Kitzler, Barbara; Zechmeister-Boltenstern, Sophie; Richter, Andreas; Sessitsch, Angela

    2010-01-01

    It was hypothesized that seasonality and resource availability altered through tree girdling were major determinants of the phylogenetic composition of the archaeal and bacterial community in a temperate beech forest soil. During a 2-year field experiment, involving girdling of beech trees to intercept the transfer of easily available carbon (C) from the canopy to roots, members of the dominant phylogenetic microbial phyla residing in top soils under girdled versus untreated control trees wer...

  5. Effects of simultaneous ozone exposure and nitrogen loads on carbohydrate concentrations, biomass, growth, and nutrient concentrations of young beech trees (Fagus sylvatica)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, V.F.D. [Institute for Applied Plant Biology, Sandgrubenstr. 25/27, 4124 Schoenenbuch (Switzerland)]. E-mail: vera.thomas@iap.ch; Braun, S. [Institute for Applied Plant Biology, Sandgrubenstr. 25/27, 4124 Schoenenbuch (Switzerland); Flueckiger, W. [Institute for Applied Plant Biology, Sandgrubenstr. 25/27, 4124 Schoenenbuch (Switzerland)

    2006-09-15

    Beech seedlings were grown under different nitrogen fertilisation regimes (0, 20, 40, and 80 kg N ha{sup -1} yr{sup -1}) for three years and were fumigated with either charcoal-filtered (F) or ambient air (O{sub 3}). Nitrogen fertilisation increased leaf necroses, aphid infestations, and nutrient ratios in the leaves (N:P and N:K), as a result of decreased phosphorus and potassium concentrations. For plant growth, biomass accumulation, and starch concentrations, a positive nitrogen effect was found, but only for fertilisations of up to 40 kg N ha{sup -1} yr{sup -1}. The highest nitrogen load, however, reduced leaf area, leaf water content, growth, biomass accumulation, and starch concentrations, whereas soluble carbohydrate concentrations were enhanced. The ozone fumigation resulted in reduced leaf area, leaf water content, shoot growth, root biomass accumulation, and decreased starch, phosphorus, and potassium concentrations, increasing the N:P and N:K ratios. A combined effect of the two pollutants was detected for the leaf area and the shoot elongation, where ozone fumigation amplified the nitrogen effects. - The effects of nitrogen and ozone on growth, carbohydrate concentrations, and nutrients are mainly additive.

  6. Effects of planted European beech on the understory in Scots pine forests of Lithuania

    Directory of Open Access Journals (Sweden)

    Marozas V

    2014-02-01

    Full Text Available Understanding how the planting of non-native species impacts native vegetation is of most importance for forest management, as introduced species may alter environmental conditions with respect to soil composition, light intensity, and species composition. Here, we compared the stand structure, understory vegetation and site properties of a natural Scots pine (Pinus sylvestris L. stand with Norway spruce (Picea abies (L. Karst. and European beech (Fagus sylvatica L. as the second tree layer. We recorded saplings and species and their abundance in the understory vegetation, the thicknesses of organic (O and humus (A soil layers, soil pH and light indexes in nine Scots pine stands with a second tree layer of beech and in nine control pine stands with a second tree layer of spruce. An ordination method was used to analyze all the data together and ANOVA to determine whether there were differences between stands. We found that species diversity in pine stands with planted beech as the second layer was lower than in pine stands with spruce as the second layer. In pine stands with beech as the second tree layer, shrub, herb and moss cover was significantly lower, and the soil humus layer and organic soil layer were thicker and thinner, respectively. Stand parameters such as mean volume and mean annual increment of the second tree layer were significantly higher in pine stands with planted beech as the second tree layer than in pine stand with spruce as the second tree layer. The mean volume and the mean annual increment of the first tree layer dominated by Scots pine did not differ significantly between stands with planted beech and those with natural spruce. Scots pine stands with a beech second layer had negative effects on understory species richness and abundance. This effect was most likely due to the lower light transmittance and poor physical properties of the forest-floor litter in the Scots pine stands with planted beech.

  7. Wybrane zagadnienia z morfogenezy liści drzew. II. Występowanie młodocianych form liści w koronach drzew buka zwyczajnego (Fagus silvatica L. [Studies on the mohprogenesis of tree-leaves. II. The occurrence of juvenile forms of leaves in the crowns of beech trees (Fagus silvatica L.

    Directory of Open Access Journals (Sweden)

    I. Więckowska

    2015-05-01

    Full Text Available It was fairly often observed that Fagus silvatica L. leafed twice during one vegetational season. This secondary growth occurred on all trees, when the first leaves underwent destruction, e.g. in consequence of late spring frost. The leaves of secondary growth differed pronouncedly from normally developed ones by their shape and irregular nervation and were similar to the juvenile leaves of one-year-old seedlings of beech. Observations of leaf buds showed that the nerves appeared in leaf-primordia of Fagus silvatica as late as the latter part of July and if the secondary leaves developed at the end of July, they were normal in shape and bad regular nervation. Leaf-primordia compelled to an earlier development gave leaves of different form and irregular nervation.

  8. Cascading effects of a highly specialized beech-aphid–fungus interaction on forest regeneration

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    Susan C. Cook-Patton

    2014-06-01

    Full Text Available Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold (Scorias spongiosa colonizes the honeydew from a specialist beech aphid (Grylloprociphilus imbricator, ultimately decreasing the survival of seedlings beneath American beech trees (Fagus grandifolia. A common garden experiment indicated that this mortality resulted from moldy honeydew impairing leaf function rather than from chemical or microbial changes to the soil. In addition, aphids consistently and repeatedly colonized the same large beech trees, suggesting that seedling-depauperate islands may form beneath these trees. Thus this highly specialized three-way beech-aphid–fungus interaction has the potential to negatively impact local forest regeneration via a cascade of indirect effects.

  9. Competition for nitrogen sources between European beech (Fagus sylvatica) and sycamore maple (Acer pseudoplatanus) seedlings.

    Science.gov (United States)

    Simon, J; Waldhecker, P; Brüggemann, N; Rennenberg, H

    2010-05-01

    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 a single label. Furthermore, fine roots were sampled and analysed for total amino acids, soluble protein, total nitrogen, nitrate and ammonium content. Our results clearly show that both tree species were able to use inorganic and organic N sources. Uptake of inorganic and organic N by beech roots was negatively affected in the presence of the competing tree species. In contrast, the presence of beech stimulated inorganic N uptake by sycamore maple roots. Both the negative effect of sycamore maple on N uptake of beech and the positive effect of beech on N uptake of sycamore maple led to an increase in root soluble protein in beech, despite an overall decrease in total N concentration. Thus, beech compensated for the negative effects of the tree competitor on N uptake by incorporating less N into structural N components, but otherwise exhibited the same strategy as the competitor, namely, enhancing soluble protein levels in roots when grown under competition. It is speculated that enhanced enzyme activities of so far unknown nature are required in beech as a defence response to inter-specific competition.

  10. Is there a Future for the Isolated Oriental Beech (Fagus orientalis Lipsky Forests in Southern Turkey?

    Directory of Open Access Journals (Sweden)

    YILMAZ, Mustafa

    2010-01-01

    Full Text Available Oriental beech (Fagus orientalis Lipsky is mainly found in the northern region of Turkey.There is also an approximate 40,000 ha of isolated relict oriental beech forest in southern Turkey. Thisrelict population differs somewhat from the northern distribution in terms of average altitudinaldistribution, health conditions, and reactions to climate change. Beech forest distribution in southernTurkey starts at about 1000 m, contrary to the northern distribution, which begins at about 150-200 m. Insouthern Turkey, the average temperature is higher, and summer drought occurs due to irregular rainfall.Beech trees in the south decay at earlier ages due to their sprout origins and higher temperatures than in thenorth. In recent decades, some part of the beech forests have shed leaves during the summer in response tosevere drought. Therefore, these relict populations are on the verge of extinction under unfavorableconditions.

  11. Different Atmospheric Methane-Oxidizing Communities in European Beech and Norway Spruce Soils▿ †

    OpenAIRE

    Degelmann, Daniela M.; Borken, Werner; Drake, Harold L; Kolb, Steffen

    2010-01-01

    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 CH4 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 d...

  12. Morphological and physiological damage to the mycorrhiza/root system in beech trees as a consequence of soil pollution, and chances of regeneration. Final report. Morphologische und physiologische Schaedigung des Mykorrhiza-Wurzel-Systems bei der Buche als Folge von Bodenbelastungen und Moeglichkeiten der Regeneration. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, H.G. (Karlsruhe Univ. (T.H.) (Germany, F.R.). Botanisches Inst. und Botanischer Garten)

    1989-01-01

    In a first partial project, the development of micorrhizas in old beech trees damaged in varying degrees was investigated. As the course of these investigations revealed, it is practically impossible to make statements on the development, frequency, vitality, and structural intactness of micorrhizas in correlation to the degree of damage of the tree. A second partial project aimed to verify whether the root section of trees sustained phytotoxic damage from the impact of pollutants under controlled conditions. The investigations concentrated on some heavy metals as stress factors, as soil analyses revealed the existence of heavy metal enrichments in the sites of observation and as the intention was to verify in how far the heavy metal resistance of seedlings is increased by developed mycorrhizas. The investigations in the field yielded no obvious result. Consequently, it is still deemed uncertain whether air pollutants harm the mycorrhizas of forest trees, be it directly via the soil or indirectly via influences on epigeal parts of the plant. Under controlled conditions in the laboratory, the author achieved the 'in vitro' synthesis of a mycorrhiza between Fagus sylvatica and Cenococcum geophilum. It provided proof of the fact that only small amounts of copper in the culture medium are needed to disturb the symbiontic equilibrium between root and fungus in a way endowing the fungus with parasitic properties. But these result obtained in an artifical substrate cannot simply be transferred to conditions in the field. (orig./MG).

  13. Assortment structure in beech coppice stands in Boljevac region

    Directory of Open Access Journals (Sweden)

    Danilović Milorad

    2004-01-01

    Full Text Available Assortment structure in beech coppice stands was studied in the area of Boljevac. Assortment structure was evaluated according to the articles of the valid standard (JUS. The assortments represented in the assortment structure, based on the stemwood quality are: Logs for matches, sawlogs I II and III classes, mine timber, technical roundwood, pulpwood, wood for excelsior and fuelwood, I and II classes. The results of the analyses show that the value assortment structure (sum of the values of assortments produced from one tree grows significantly with the increase of tree diameter and this dependence is presented by a degree function. The value percentage of logs for matches, sawlogs of the I and II classes, technical roundwood, mine timber, fuelwood and pulpwood, grows with the increase of the tree diameter. The occurrence of better quality logs (sawlogs in these stands, in contrast to the beech coppice stand in the area of Crni Vrh results from the more favourable diameter structure. There are no statistically significant differences between the value assortment structure on the established sample plot series within the same locality, consequently the data ere united. Because of the differences in stand age, the data are not unified for the localities, although there are no statistically significant differences between value assortment structure for diameter degrees represented in them. False heart (red heart is one of very significant defects of beech wood, and its incidence, inter alia, depends on tree age. The low effect of this defect of wood resulted in a significant percentage of logs for matches. Along with the value assortment structure this paper also presents the percentage of assortments depending on tree diameter.

  14. Variation in Ecophysiological Traits and Drought Tolerance of Beech (Fagus sylvatica L.) Seedlings from Different Populations.

    Science.gov (United States)

    Cocozza, Claudia; de Miguel, Marina; Pšidová, Eva; Ditmarová, L'ubica; Marino, Stefano; Maiuro, Lucia; Alvino, Arturo; Czajkowski, Tomasz; Bolte, Andreas; Tognetti, Roberto

    2016-01-01

    Frequency and intensity of heat waves and drought events are expected to increase in Europe due to climate change. European beech (Fagus sylvatica L.) is one of the most important native tree species in Europe. Beech populations originating throughout its native range were selected for common-garden experiments with the aim to determine whether there are functional variations in drought stress responses among different populations. One-year old seedlings from four to seven beech populations were grown and drought-treated in a greenhouse, replicating the experiment at two contrasting sites, in Italy (Mediterranean mountains) and Germany (Central Europe). Experimental findings indicated that: (1) drought (water stress) mainly affected gas exchange describing a critical threshold of drought response between 30 and 26% SWA for photosynthetic rate and Ci/Ca, respectively; (2) the Ci to Ca ratio increased substantially with severe water stress suggesting a stable instantaneous water use efficiency and an efficient regulation capacity of water balance achieved by a tight stomatal control; (3) there was a different response to water stress among the considered beech populations, differently combining traits, although there was not a well-defined variability in drought tolerance. A combined analysis of functional and structural traits for detecting stress signals in beech seedlings is suggested to assess plant performance under limiting moisture conditions and, consequently, to estimate evolutionary potential of beech under a changing environmental scenario. PMID:27446118

  15. Differential responses of herbivores and herbivory to management in temperate European beech.

    Science.gov (United States)

    Gossner, Martin M; Pašalić, Esther; Lange, Markus; Lange, Patricia; Boch, Steffen; Hessenmöller, Dominik; Müller, Jörg; Socher, Stephanie A; Fischer, Markus; Schulze, Ernst-Detlef; Weisser, Wolfgang W

    2014-01-01

    Forest management not only affects biodiversity but also might alter ecosystem processes mediated by the organisms, i.e. herbivory the removal of plant biomass by plant-eating insects and other arthropod groups. Aiming at revealing general relationships between forest management and herbivory we investigated aboveground arthropod herbivory in 105 plots dominated by European beech in three different regions in Germany in the sun-exposed canopy of mature beech trees and on beech saplings in the understorey. We separately assessed damage by different guilds of herbivores, i.e. chewing, sucking and scraping herbivores, gall-forming insects and mites, and leaf-mining insects. We asked whether herbivory differs among different forest management regimes (unmanaged, uneven-aged managed, even-aged managed) and among age-classes within even-aged forests. We further tested for consistency of relationships between regions, strata and herbivore guilds. On average, almost 80% of beech leaves showed herbivory damage, and about 6% of leaf area was consumed. Chewing damage was most common, whereas leaf sucking and scraping damage were very rare. Damage was generally greater in the canopy than in the understorey, in particular for chewing and scraping damage, and the occurrence of mines. There was little difference in herbivory among differently managed forests and the effects of management on damage differed among regions, strata and damage types. Covariates such as wood volume, tree density and plant diversity weakly influenced herbivory, and effects differed between herbivory types. We conclude that despite of the relatively low number of species attacking beech; arthropod herbivory on beech is generally high. We further conclude that responses of herbivory to forest management are multifaceted and environmental factors such as forest structure variables affecting in particular microclimatic conditions are more likely to explain the variability in herbivory among beech forest

  16. SOIL CO2 EFFLUX FROM ISOTOPICALLY LABELED BEECH AND SPRUCE IN SOUTHERN GERMANY

    Science.gov (United States)

    • Carbon acquisition and transport to roots in forest trees is difficult to quantify and is affected by a number of factors, including micrometeorology and anthropogenic stresses. The canopies of mature European beech (Fagus sylvatica) and Norway spruce (Picea abies) were expose...

  17. The proposition of optimal silvicultural-reclamation operations in untended beech stands of mixed origin

    Directory of Open Access Journals (Sweden)

    Krstić Milun

    2004-01-01

    Full Text Available The state, quality, spontaneous development and silvicultural demands of untended beech stands of mixed origin were studied, the age of trees in the dominant layer is about 75 years. The analysis of stand development through a 17-year period (1986-2003 included the monitoring of the elements of stand structure: Number of trees, basal area, volume, diameter and volume increment, mean stand diameter, structure, mortality and tree removal from the stand, morphological, biological and technical characteristics of trees and biological differentiation of trees. The adequate silvicultural-reclamation measures are proposed based on the identified stand state.

  18. Effect of canopy gap size and ecological factors on species diversity and beech seedlings in managed beech stands in Hyrcanian forests

    Institute of Scientific and Technical Information of China (English)

    Kambiz Abrari Vajari; Hamid Jalilvand; Mohammad Reza Pourmajidian; Kambiz Espahbodi; Alireza Moshki

    2012-01-01

    We studied the species diversity of the herb layer and ecological factors in harvest-created gaps in beech stands under a single-tree selection system in Northern Iran.To determine diversity,the number of beech seedlings,and other ecological factors,16 gaps were selected and subplots of 5 m2 were positioned at the centre and at the cardinal points of each gap.Species richness and Simpson diversity index increased with increasing gap area as did numbers of seedlings.with increasing humus layer thickness,species richness declined but the Hill evenness index increased.Species richness increased with increasing light availability.There was no relationship between crown radii of beech trees and diversity indices.Correlations between environmental factors and numbers of individuals of some species in the herb layer were not significant except in a few cases.The results help explain the effects of man-made gaps on the dynamics of mnanaged beech stands and this benefits evaluation of silvicultural operating plans.

  19. Finders keepers, losers weepers - drought as a modifier of competition between European beech and Norway spruce -

    Science.gov (United States)

    Goisser, Michael; Blanck, Christian; Geppert, Uwe; Häberle, Karl-Heinz; Matyssek, Rainer; Grams, Thorsten E. E.

    2016-04-01

    Mixed stands of European beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) Karst.) frequently reflect over-yielding, when compared to respective monospecific stands. Over-yielding is attributed to enhanced resource uptake efficiency through niche complementarity alleviating species competition. Under climate change, however, with severe and frequent summer drought, water limitation may become crucial in modifying the competitive interaction between neighboring beech and spruce trees. In view of the demands by silvicultural practice, basic knowledge from experimental field work about competitive versus facilitative interaction in maturing mixed beech-spruce forests is scarce. To this end, we investigate species-specific drought response including underlying mechanisms of species interaction in a maturing group-wise mixed beech-spruce forest, amongst 60 and 53 adult trees of beech and spruce, respectively (spruce 65 ± 2, beech 85 ± 4 years old). Severe and repeated experimental drought is being induced over several years through a stand-scale approach of rain throughfall exclusion (Kranzberg Forest Roof Experiment, KROOF). The experimental design comprises 6 roofed (E, automated, closing only during rain) and 6 control (C) plots with a total area of almost 1800 square meters. In 2015 minimum predawn potentials of -2.16 MPa and -2.26 MPa were reached in E for beech and spruce respectively. At the leaf level, spruce displayed high drought susceptibility reflected by a distinct decrease in both stomatal conductance and net CO2 uptake rate by more than 80% each, suggesting isohydric response. Beech rather displayed anisohydry indicated by less pronounced yet significant reduction of stomatal conductance and net CO2 uptake rate by more than 55% and 45%, respectively. Under the C regime, a negative species interaction effect on stomatal conductance was found in beech, contrasting with a positive effect in spruce. However, drought reversed the effect of

  20. Trees

    Science.gov (United States)

    Al-Khaja, Nawal

    2007-01-01

    This is a thematic lesson plan for young learners about palm trees and the importance of taking care of them. The two part lesson teaches listening, reading and speaking skills. The lesson includes parts of a tree; the modal auxiliary, can; dialogues and a role play activity.

  1. Seasonal variation in N uptake strategies in the understorey of a beech-dominated N-limited forest ecosystem depends on N source and species.

    Science.gov (United States)

    Li, Xiuyuan; Rennenberg, Heinz; Simon, Judy

    2016-05-01

    In forest ecosystems, species use different strategies to increase their competitive ability for nitrogen (N) acquisition. The acquisition of N by trees is regulated by tree internal and environmental factors including mycorrhizae. In this study, we investigated the N uptake strategies of three co-occurring tree species [European beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and Norway maple (Acer platanoides L.)] in the understorey of a beech-dominated, N-limited forest on calcareous soil over two consecutive seasons. For this purpose, we studied (15)N uptake capacity as well as the allocation to N pools in the fine roots. Our results show that European beech had a higher capacity for both inorganic and organic N acquisition throughout the whole growing season compared with sycamore maple and Norway maple. The higher capacity of N acquisition in beech indicates a better adaption of beech to the understorey conditions of beech forests compared with the seedlings of other tree competitors under N-limited conditions. Despite these differences, all three species preferred organic over inorganic N sources throughout the growing season and showed similar seasonal patterns of N acquisition with an increased N uptake capacity in summer. However, this pattern varied with N source and year indicating that other environmental factors not assessed in this study further influenced N acquisition by the seedlings of the three tree species.

  2. Seasonal variation in N uptake strategies in the understorey of a beech-dominated N-limited forest ecosystem depends on N source and species.

    Science.gov (United States)

    Li, Xiuyuan; Rennenberg, Heinz; Simon, Judy

    2016-05-01

    In forest ecosystems, species use different strategies to increase their competitive ability for nitrogen (N) acquisition. The acquisition of N by trees is regulated by tree internal and environmental factors including mycorrhizae. In this study, we investigated the N uptake strategies of three co-occurring tree species [European beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and Norway maple (Acer platanoides L.)] in the understorey of a beech-dominated, N-limited forest on calcareous soil over two consecutive seasons. For this purpose, we studied (15)N uptake capacity as well as the allocation to N pools in the fine roots. Our results show that European beech had a higher capacity for both inorganic and organic N acquisition throughout the whole growing season compared with sycamore maple and Norway maple. The higher capacity of N acquisition in beech indicates a better adaption of beech to the understorey conditions of beech forests compared with the seedlings of other tree competitors under N-limited conditions. Despite these differences, all three species preferred organic over inorganic N sources throughout the growing season and showed similar seasonal patterns of N acquisition with an increased N uptake capacity in summer. However, this pattern varied with N source and year indicating that other environmental factors not assessed in this study further influenced N acquisition by the seedlings of the three tree species. PMID:26786538

  3. Biomass and nutrients allocation in pot cultured beech seedlings:influence of nitrogen fertilizer

    Institute of Scientific and Technical Information of China (English)

    Ali Bagherzadeh; Rainer Brumme; Friedrich Beese

    2008-01-01

    Allocation of biomass and nutrient elements including Nitrogen to above and belowground compartments of beech seedlings (Fagus sylvatica L.) treated by labeled nitrogen fertilizer in the form of 15NH4 and 15NO3 were investigated at the end of two successive growing seasons.Pot cultured beech seedlings were grown at a green house on intact soil cores sampled from three adjacent stands including beech,Norway spruce and mixed beech-spruce cultures of Solling forest,Germany.Comparing biomass allocation and nutrients concentrations of the seedlings between the control and 15N-fertilized treatments revealed no significant effect of N fertilization on nutrients uptake by seedlings over the experiment.The form of N input influenced its movement into plant pools.It was demonstrated that beech seedlings take up nitrogen mainly in the form of nitrate,which is then reduced in the leaves,although the differences between the retention of NO3 ̄-N and NH4+-N in plants were not statistically significant.Percent recoveries of 15N in trees were typically greater after 15NO3 than after 15NH4 additions.It was indicated that immobilization of 15N tracer in fine roots was a slower process comparing other plant compartments such as stem and coarse roots,but a powerful sink for N during the course of study.

  4. Chemical remediation of beech condensates.

    Science.gov (United States)

    Irmouli, Mohammed; Haluk, Jean Pierre

    2005-01-01

    In the present work, beech wood condensates are separated from the aqueous phase. Experimental results reveal an electrostatic interaction between the oppositely charged wood extracts after oxidation and Ca(OH)(2). The increase in aqueous phase pH resulted in enhanced removal of wood extracts from water. The polarographic assays were carried out at 25 degrees C using a Gilson oxygraph equipped with a Clark electrode in order to determine the oxygen uptake during the oxidation reaction. The effect of pH is explained based on oxygen uptake. The organic compounds found in the aqueous effluent are responsible for the brown color. The objective of this study is to find the optimum pH to eliminate the wood extracts from the liquid effluents. PMID:15567404

  5. Patterns of mast fruiting of common beech, sessile and common oak, Norway spruce and Scots pine in Central and Northern Europe

    DEFF Research Database (Denmark)

    Nussbaumer, Anita; Waldner, Peter; Etzold, Sophia;

    2016-01-01

    Occurrence of mast years, i.e. the synchronous production of vast amounts of fruits or seeds, has an important impact on forest ecosystems, their functioning and their services. We investigated the mast patterns of the forest tree species common beech, common and sessile oak, Norway spruce and Sc...... hypotheses, and beech and spruce supported the economy of scale, predator satiation and resource allocation hypotheses....

  6. Greater accumulation of litter in spruce (Picea abies) compared to beech (Fagus sylvatica) stands is not a consequence of the inherent recalcitrance of needles

    OpenAIRE

    Berger, Torsten W.; Berger, Pétra

    2012-01-01

    Background and aims Replacement of beech by spruce is associated with changes in soil acidity, soil structure and humus form, which are commonly ascribed to the recalcitrance of spruce needles. It is of practical relevance to know how much beech must be admixed to pure spruce stands in order to increase litter decomposition and associated nutrient cycling. We addressed the impact of tree species mixture within forest stands and within litter on mass loss and nutritional release from litter. M...

  7. Trees

    CERN Document Server

    Epstein, Henri

    2016-01-01

    An algebraic formalism, developped with V.~Glaser and R.~Stora for the study of the generalized retarded functions of quantum field theory, is used to prove a factorization theorem which provides a complete description of the generalized retarded functions associated with any tree graph. Integrating over the variables associated to internal vertices to obtain the perturbative generalized retarded functions for interacting fields arising from such graphs is shown to be possible for a large category of space-times.

  8. Assortment structure in beech coppice stands in the Crni vrh region

    Directory of Open Access Journals (Sweden)

    Danilović Milorad

    2003-01-01

    Full Text Available Assortment structure in beech coppice stands was studied for the region of Crni vrh. Assortment structure was determined according to the standard (JUS in two ecological units. The study results show that the assortment value structure significantly increases with the increase of tree diameter and that there are no statistically significant differences in assortment structure between the selected ecological units. The dependence of the assortment value structure on tree diameter can be represented by an exponential function. The value percentage of assortments made of stem wood in theoretical crosscutting depending on tree diameter has an increasing tendency, except for the wood for excelsior.

  9. INVASION OF BEECH AND E STABLISHMENT OF BEECH FORESTS IN EUROPE

    Directory of Open Access Journals (Sweden)

    R. POTT

    1997-01-01

    Full Text Available When studying the natural development in the evolution of beechwood forests in Central Europe after the last glaciation, it is necessary to look at the warm periods prior to the last Weichselian glaciation. The Eem interglacial period has already been studied in great detail in Europe; it is evidend with similar climatic conditions as the current Holocene. At that time nearly all of Europe was more or less completely covered with forests. As laminated sediments and datings indicate, the Eem interglacial period lasted from approximately 125000 to 113000 years before today. The types of trees were generally the same as those of the present, except for the beech (Fagus which was missing due to its delayed re-migration and was replaced by the hornbeam (Carpinus. It was not until the present time following the glaciation-periods that Fagus sylvatica could be found again widespread throughout the woodland vegetation covering Central Europe. The Holocene expansion and re-colonisation of Fagus sylvatica from its refuges during the glacial periods will be described in great detail, based on the most recent pollen analytic proofs.

  10. Effects of planted European beech on the understory in Scots pine forests of Lithuania

    OpenAIRE

    Marozas V; Augustaitis A; Armolaitis K; Kliucius A; Pilkauskas M

    2014-01-01

    Understanding how the planting of non-native species impacts native vegetation is of most importance for forest management, as introduced species may alter environmental conditions with respect to soil composition, light intensity, and species composition. Here, we compared the stand structure, understory vegetation and site properties of a natural Scots pine (Pinus sylvestris L.) stand with Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) as the second tree lay...

  11. Measuring and modelling precipitation components in an Oriental beech stand of the Hyrcanian region, Iran

    Science.gov (United States)

    Rahmani, Ramin; Sadoddin, Amir; Ghorbani, Somayeh

    2011-07-01

    SummaryInterception loss from the canopy is a major pathway for the loss of water from forest ecosystems. This study was conducted in an Oriental beech stand, neighboring Gorgan, representing typical forest characteristics of the Hyrcanian region. The Hyrcanian region is situated to the south of the Caspian Sea and covers approximately 1.8 million ha of the northern foothills of the Alborz Mountains in northern Iran. This region is characterised by temperate deciduous forests with Oriental beech stands, formed mainly of Fagus orientalis. Because these beech stands occupy 80% of the Hyrcanian region, rainfall interception via the tree canopy is an important pathway for water loss in this region. The main objectives of this study were to determine and model the precipitation components including stemflow, throughfall, net precipitation, and interception loss using gross precipitation and to understand how the diameter classes influence precipitation partitioning by comparing precipitation components across the tree diameter classes. A total of 31 beech trees with the following classes of diameter were randomly chosen: 11 trees of 30-60 cm (young), 10 trees of 60-100 cm (middle-aged), and 10 trees of 100-130 cm (old) of Diameter at Breast Height (DBH). Field measurements of gross precipitation, stemflow, and throughfall were made for 33 rainfall events over a period of 12 months from November 2005. Then, based on these measurements, net precipitation and interception loss were calculated. The value of gross precipitation was approximately 827 mm. Interception loss estimated to be about 53%, 57%, and 60% of gross precipitation corresponding to the tree diameter classes of 30-60, 60-100, and 100-130 cm, respectively. ANOVA results show that the values of the mean of precipitation components were significantly different across the diameter classes. There was an indirect relationship between tree diameter and the volumes of stemflow, throughfall, and net precipitation

  12. The effects of habitat degradation on metacommunity structure of wood-inhabiting fungi in European beech forests

    DEFF Research Database (Denmark)

    Halme, Panu; Odor, Peter; Christensen, Morten;

    2013-01-01

    with different management histories. For this purpose, we used a large data set of wood-inhabiting fungi collected from dead beech trees in European beech-dominated forest reserves. The structure of fungal assemblages showed high beta diversity, while nestedness and similarity was low. During the decomposition......Intensive forest management creates habitat degradation by reducing the variation of forest stands in general, and by removing old trees and dead wood in particular. Non-intervention forest reserves are commonly believed to be the most efficient tool to counteract the negative effects...... process of trees beta diversity between the communities occupying different trees increased in natural, but not in previously managed sites. Effects of management and decay process on nestedness were complex. We argue that the detected differences most likely reflect historical effects which have...

  13. Natural Regeneration of Beech Forests in the Strict Protected Area of the Plitvice Lakes National Park

    Directory of Open Access Journals (Sweden)

    Tomislav Dubravac

    2013-12-01

    Full Text Available Background and Purpose: The study presents the results of an investigation of regeneration processes, growth, development and survival of young growth by field measurement and three-dimensional visualization of horizontal and vertical structure. The results are based on the ten-year investigation (1998-2009 on a permanent experimental plot in a mountain beech forest with dead nettle tree (Lamio orvale - Fagetum sylvaticae Ht. 1938 in conditions of passive protection. Materials and Methods: Basic structural indicators were measured (diameter at breast height and height, structural crown elements (size and shape, ground cover crowns and the occurrence and survival of young growth as the basic conditions of natural regeneration. Particular emphasis in the investigation was paid to the development of crown structures and the process of natural regeneration during the 10 year period. Results and Conclusions: Investigation indicates the occurrence of young growth regeneration cores arising as a result of the die-back of one dominant beech tree with horizontal crown projections of 145 m2 which initiated the possibility of natural regeneration. The greatest change occurred in the beech seedling count, whose numbers increased fourfold from 3556 plants per hectare in 1998 to 12694 plants per hectare in 2009. The share of beech seedlings increased from 8.7% to 22.6% of all species of young growth and shrubs. Thus beech became dominant among the tree species regeneration. However, the majority of the young plants of beech are of poor quality and thus their further development in conditions of passive protection is questionable. The investigations also showed the possibility of a new approach to the study of the dynamics of crown structures and the process of natural regeneration by methods of three-dimensional visualization of horizontal and vertical structures. The methods presented offer a more graphic illustration of the development of stands and high

  14. Effect of CO2 enhancement on beech (Fagus sylvatica L. seedling root rot due to Phytophthora plurivora and Phytophthora cactorum

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2014-09-01

    Full Text Available Global climate change is associated with higher concentrations of atmospheric carbon dioxide (CO2. The ongoing changes are likely to have significant, direct or indirect effects on plant diseases caused by many biotic agents such as phytopathogenic fungi. This study results showed that increased CO2 concentration did not stimulate the growth of 1-year-old beech Fagus sylvatica L seedlings but it activated pathogenic Phytophthora species (P. plurivora and P. cactorum which caused significant reduction in the total number of fine roots as well as their length and area. The results of the greenhouse experiment indicated that pathogens once introduced into soil survived in pot soil, became periodically active (in sufficient water conditions and were able to damage beech fine roots. However, the trees mortality was not observed during the first year of experiment. DNA analyses performed on soil and beech tissue proved persistence of introduced Phytophthora isolates.

  15. Desiccation and Mortality Dynamics in Seedlings of Different European Beech (Fagus sylvatica L.) Populations under Extreme Drought Conditions

    Science.gov (United States)

    Bolte, Andreas; Czajkowski, Tomasz; Cocozza, Claudia; Tognetti, Roberto; de Miguel, Marina; Pšidová, Eva; Ditmarová, Ĺubica; Dinca, Lucian; Delzon, Sylvain; Cochard, Hervè; Ræbild, Anders; de Luis, Martin; Cvjetkovic, Branislav; Heiri, Caroline; Müller, Jürgen

    2016-01-01

    European beech (Fagus sylvatica L., hereafter beech), one of the major native tree species in Europe, is known to be drought sensitive. Thus, the identification of critical thresholds of drought impact intensity and duration are of high interest for assessing the adaptive potential of European beech to climate change in its native range. In a common garden experiment with one-year-old seedlings originating from central and marginal origins in six European countries (Denmark, Germany, France, Romania, Bosnia-Herzegovina, and Spain), we applied extreme drought stress and observed desiccation and mortality processes among the different populations and related them to plant water status (predawn water potential, ΨPD) and soil hydraulic traits. For the lethal drought assessment, we used a critical threshold of soil water availability that is reached when 50% mortality in seedling populations occurs (LD50SWA). We found significant population differences in LD50SWA (10.5–17.8%), and mortality dynamics that suggest a genetic difference in drought resistance between populations. The LD50SWA values correlate significantly with the mean growing season precipitation at population origins, but not with the geographic margins of beech range. Thus, beech range marginality may be more due to climatic conditions than to geographic range. The outcome of this study suggests the genetic variation has a major influence on the varying adaptive potential of the investigated populations. PMID:27379105

  16. Desiccation and Mortality Dynamics in Seedlings of Different European Beech (Fagus sylvatica L.) Populations under Extreme Drought Conditions.

    Science.gov (United States)

    Bolte, Andreas; Czajkowski, Tomasz; Cocozza, Claudia; Tognetti, Roberto; de Miguel, Marina; Pšidová, Eva; Ditmarová, Ĺubica; Dinca, Lucian; Delzon, Sylvain; Cochard, Hervè; Ræbild, Anders; de Luis, Martin; Cvjetkovic, Branislav; Heiri, Caroline; Müller, Jürgen

    2016-01-01

    European beech (Fagus sylvatica L., hereafter beech), one of the major native tree species in Europe, is known to be drought sensitive. Thus, the identification of critical thresholds of drought impact intensity and duration are of high interest for assessing the adaptive potential of European beech to climate change in its native range. In a common garden experiment with one-year-old seedlings originating from central and marginal origins in six European countries (Denmark, Germany, France, Romania, Bosnia-Herzegovina, and Spain), we applied extreme drought stress and observed desiccation and mortality processes among the different populations and related them to plant water status (predawn water potential, ΨPD) and soil hydraulic traits. For the lethal drought assessment, we used a critical threshold of soil water availability that is reached when 50% mortality in seedling populations occurs (LD50SWA). We found significant population differences in LD50SWA (10.5-17.8%), and mortality dynamics that suggest a genetic difference in drought resistance between populations. The LD50SWA values correlate significantly with the mean growing season precipitation at population origins, but not with the geographic margins of beech range. Thus, beech range marginality may be more due to climatic conditions than to geographic range. The outcome of this study suggests the genetic variation has a major influence on the varying adaptive potential of the investigated populations. PMID:27379105

  17. Spatiogenetic characteristics of beech stands with different degrees of autochthony

    Science.gov (United States)

    Gregorius, Hans-Rolf; Kownatzki, Dierk

    2005-01-01

    Background Autochthony in forest tree stands is characterized by a number of criteria, among which the range over which stands act as a population has been suggested to play a central role. Therefore, measures are needed for the delineation of populations or the detection of subpopulation structure. It is argued here that methods of population delineation must be based on the combined consideration of spatial distances and genetic differences between adult individuals. Conventional approaches and a set of newly developed methods are applied to seven isozyme loci in four beech stands which are distinguished by different types of forest management based on natural regeneration. Results Permutation analyses show that correlations between spatial distances and genetic differences vary only little in the studied beech stands. In view of the popularity of this and related descriptors of spatiogenetic covariation, this result came as a surprise. The newly developed methods lead to a different conclusion. Significant spatiogenetic structure is indicated in all stands when considering the mean and variance of spatiogenetic separation, where separation is measured by the smallest spatiogenetic difference of an individual from all others. Spatiogenetic difference is measured here by a combination of the spatial distances and genetic differences between individuals. This descriptor indicates the existence of spatiogenetic clusters in the beech stands. In order to arrive at an explicit representation of cluster structure as a representation of subpopulation structure, two types of cluster structure (primary and α-isolated) are distinguished, both of which reflect desirable characteristics of subpopulation structure. Particularly in the α-isolated structure, the proportion of individuals organized in clusters, the effective size, and the effective number of clusters clearly distinguish and consistently rank the four stands with respect to their types of forest management and

  18. Radial variations in cation exchange capacity and base saturation rate in the wood of pedunculate oak and European beech

    Energy Technology Data Exchange (ETDEWEB)

    Herbauts, J.; Penninckx, V.; Gruber, W.; Meerts, P. [Universite Libre de Bruxelles, Laboratoire de genetique et d' ecologie vegetales, Brussels (Belgium)

    2002-10-01

    Visual observation of pedunculate oak trees and European beech trees in a mixed forest stand in the Belgian Ardennes revealed decreasing cation concentration profiles in wood. In order to determine whether these profiles are attributable to endogenous factors or to decreased availability of cations in the soil, radial profiles of water-soluble, exchangeable and total cations were investigated. Cation exchange capacity of wood was also determined. Results showed wood cation exchange capacity to decrease from pith to bark in European beech and from pith to outer heartwood in pedunculate oak. Decreasing profiles of exchangeable calcium and magnesium in peduncular oak and exchangeable calcium in European beech were found to be strongly constrained by cation exchange capacity, and thus not related to environmental change. Base cation saturation rate showed no consistent radial change in either species. It was concluded that the results did not provide convincing evidence to attribute the decrease in divalent cation concentration in pedunculate oak and European beech in this location to be due to atmospheric pollution. 42 refs., 1 tab., 4 figs.

  19. Diversity and primary productivity of hill beech forests from Doftana Valley (Romanian Subcarpathians

    Directory of Open Access Journals (Sweden)

    Mihaela Paucã-Comãnescu

    2009-11-01

    Full Text Available The hill beech forests cover most of the woody area in the Doftana Valley. The present study refers, for the first time, to two beech forests typical to this belt, which belong to the phytocoenological associations Epipactieto-Fagetum (Resmeritã,1972, in the Lunca Mare area, and Hieracio rotundati-Fagetum (Vida 1983, Täuber 1987 in the Sotrile area, from floristic, structural, biomass and necromassaccumulation point of view, within the framework of the vertical structure of biocoenosis.The limestone substratum, occasionally with small outcrops in the first beech forest, differs chiefly through the pH levels (6.34-5.67 from the siliceous substratum (pH 5.11-4.36 in the second beech forest. The layer of trees is dominated by Fagus sylvatica in both forests; this species is associated with Cerasus avium (4.5%,Acer pseudoplatanus (2% and Sorbus torminalis (2% in the first beech forest, and is monodominant in the second. Although the forest underwent selective cuts, more intense in the Lunca Mare area, the aboveground ligneous biomass reaches nowadays 222 t/ha in the Lunca Mare area compared to only 163 t/ha in the Sotrile area; theaverage height is 28.8±2.49 m and 23.7±1.12 m, respectively, and the diameter is 33.30±7.9 cm and 31.60±6.28 cm, respectively. The species of macrofungi, not very numerous during the study because of scarce precipitations (6 and 7 species, respectively,are predominant on the rhytidoma trees in the beech forest rooted on the limestone ground; in the Sotrile beech forest they are joined by mycorrhizal and parasite species. The layer of shrub is underdeveloped. The herbaceous layer is discontinuous, and includes, along herbs, small plants and saplings belonging to the ligneous species and to liana Hedera helix. The maximal value of the aboveground biomass of thelayer is 317 kg/ha DM in the Lunca Mare area and 235 kg /ha DM in the Sotrile area.Bryophyta is present in large quantities, especially in the ªotrile area

  20. TORREFACTION OF BEECH AND SPRUCE SAWDUST

    Directory of Open Access Journals (Sweden)

    Tatiana GRÎU

    2014-06-01

    Full Text Available This paper aims to apply a thermal treatment of beech and spruce sawdust dried to 10% moisture in order to determine the mass loss and to obtain pellet sets. This paper considers the colour change of the treated material during the treatment, as function of time and temperature increase. It also highlights the changes in the chemical composition of sawdust connected with the mass loss. The paper also studies the physical integrity of the obtained pellets, using the method of free fall, with the results showing that spruce sawdust pellets appear to be more stable. The optimal temperature of thermal treatment proves to be 2600C and the duration of treatments are 5 and 10 minutes, when the sawdust has dimensions between 0.4-1mm. Regarding the pellets formed at the temperature above 2600C, it should be noted that their stability is low, in particular that one of beech, which is difficult to compress and compact

  1. VOC emissions from beech, birch, and oak

    Science.gov (United States)

    Wildt, J.; Folkers, A.; Koch, N.; Kleist, E.

    2003-04-01

    VOC emissions from beech (Fagus sylvatica), birch (Betula pendula), and oak (Quercus robur) were studied in continuously stirred tank reactors. Oak emitted nearly exclusively isoprene. The dependence of these isoprene emissions on temperature and photosynthetic radiation (PAR) could quite well be described with existing algorithms and the emission factors were fairly constant. Beech and birch emitted mainly short chained oxygenated VOC and monoterpenes. Temperature and PAR dependence of monoterpene emissions were superimposed by a slow frequency modulation. Hence, descriptions of these emissions with existing algorithms were not successful. Moreover, in some cases the emission pattern switched drastically. For birch it was observed that the plant switched from a sesquiterpene emitter to a monoterpene emitter. emission pattern plants. Emissions of ethanol, acetaldehyde, and methanol were not affected by PAR. Here, the emission factors are determined by other factors not included in existing algorithms.

  2. Edaphic potentials of beech forests on Brezovica

    Directory of Open Access Journals (Sweden)

    Knežević Milan

    2002-01-01

    Full Text Available The study deals with the soils in the montane beech forest (Fagetum moesiacae montanum Jov. 53 in the management units "Južni Kuèaj II" and "Bogovina I", on the mountain massif Brezovica. Soil genesis in the beech forests of Brezovica, along with vegetation and relief, was affected by the character of parent rock. The study soils occur over two types of bedrock: limestone and argilloschist The soil types and sub-types are defined based on the profile morphology, parent rock and pedogenetic processes Two types of soil were analysed on limestone: black earth (calcomelanosol and brown soil (calcocambisol. Two sub-types of black earth were defined: organomineral and brownised. There are two varieties of organomineral black earth: colluvial and lithic. Also two sub-types of brown soils were defined and: typical and illimerised. The soils on limestone are characterised by great spatial variability. Different combinations of soil formations occur on a small area. Soil combinations consist of two or three development phases, the most represented of which are the following: organomineral black earth - brownised black earth; organomineral black earth - brownised black earth - typical brown soil; typical brown soil - illimerised soil Typical brown soil is formed on argilloschists and it occurs in two forms: medium deep, medium skeletal acid brown soil and deep, poorly skeletal acid brown soil The most productive sites of the montane beech forest on Brezovica are deep acid brown soils and the soil combination: typical brown soil - illimerised soil on limestone.

  3. Major Changes in Growth Rate and Growth Variability of Beech (Fagus sylvatica L. Related to Soil Alteration and Climate Change in Belgium

    Directory of Open Access Journals (Sweden)

    Nicolas Latte

    2016-08-01

    Full Text Available Global change—particularly climate change, forest management, and atmospheric deposition—has significantly altered forest growing conditions in Europe. The influences of these changes on beech growth (Fagus sylvatica L. were investigated for the past 80 years in Belgium, using non-linear mixed effects models on ring-width chronologies of 149 mature and dominant beech trees (87–186 years old. The effects of the developmental stage (i.e., increasing tree size were filtered out in order to focus on time-dependent growth changes. Beech radial growth was divided into a low-frequency signal (=growth rate, mainly influenced by forest management and atmospheric deposition, and into a high-frequency variability (≈mean sensitivity, mainly influenced by climate change. Between 1930 and 2008, major long-term and time-dependent changes were highlighted. The beech growth rate has decreased by about 38% since the 1950–1960s, and growth variability has increased by about 45% since the 1970–1980s. Our results indicate that (1 before the 1980s, beech growth rate was not predominantly impacted by climate change but rather by soil alteration (i.e., soil compaction and/or nitrogen deposition; and (2 since the 1980s, climate change induced more frequent and intense yearly growth reductions that amplified the growth rate decrease. The highlighted changes were similar in the two ecoregions of Belgium, although more pronounced in the lowlands than in the uplands.

  4. Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates in northwestern Turkey

    OpenAIRE

    Sariyildiz T; Savaci G; Kravkaz IS

    2016-01-01

    Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates were investigated in the northwest of Turkey using 4 common tree species as black pine (Pinus nigra Arnold.), Scots pine (Pinus sylvestris L.), Oriental beech (Fagus orientalis Lipsky) and Uludag fir (Abies nordmanniana ssp. bornmuelleriana). Three tree species (black pine, Scots pine and Oriental beech) were used to investigate the differences in soil C and N among tree species. Old and young Uluda...

  5. The Decline of Vitality Caused by Increasing Drought in a Beech Provenance Trial Predicted by Juvenile Growth

    OpenAIRE

    Horváth, Anikó; Mátyás, Csaba

    2016-01-01

    Background and Purpose: Due to rapidly changing environmental conditions, locally adapted tree populations are likely to experience climate conditions to which they are not well adapted. Common garden experiments provide a powerful tool for studying adaptive responses in changing climates. Out of the 1998 series of international beech provenance trials, one experiment was established in Bucsuta, SW Hungary. Because of its peripheral location, this is probably the most apposite site in the exp...

  6. Content of Total Phenols in Red Heart and Wound-Associated Wood in Beech (Fagus sylvatica L.

    Directory of Open Access Journals (Sweden)

    Viljem Vek

    2013-03-01

    Full Text Available The structure of wound-associated wood has been relatively well studied in beech, but only a little information about the occurrence of extractives and particular classes of compounds in these tissues is available. We examined the content of total phenols and variability in their distribution in sapwood, wound-wood and the reaction zones walling-off typical red heart and xylem altered by wounding in two beech trees, using spectrophotometric method. Significant differences in total phenols in different types of beech wood, as well as differences between trees, were confi rmed. Concentrations of total phenols were markedly lower in red heart than in reaction zones and sapwood extracts. The content of total phenols was highest in extracts of the reaction zones formed as a direct response of sapwood to wounding. Differences in the content of total phenols in reaction zones walling-off typical red heart and directly wounded xylem indicate differences in their formation process, in alterations to surrounding tissues and in the characteristics of individual trees.

  7. Climate Change Impairs Nitrogen Cycling in European Beech Forests.

    Science.gov (United States)

    Dannenmann, Michael; Bimüller, Carolin; Gschwendtner, Silvia; Leberecht, Martin; Tejedor, Javier; Bilela, Silvija; Gasche, Rainer; Hanewinkel, Marc; Baltensweiler, Andri; Kögel-Knabner, Ingrid; Polle, Andrea; Schloter, Michael; Simon, Judy; Rennenberg, Heinz

    2016-01-01

    European beech forests growing on marginal calcareous soils have been proposed to be vulnerable to decreased soil water availability. This could result in a large-scale loss of ecological services and economical value in a changing climate. In order to evaluate the potential consequences of this drought-sensitivity, we investigated potential species range shifts for European beech forests on calcareous soil in the 21st century by statistical species range distribution modelling for present day and projected future climate conditions. We found a dramatic decline by 78% until 2080. Still the physiological or biogeochemical mechanisms underlying the drought sensitivity of European beech are largely unknown. Drought sensitivity of beech is commonly attributed to plant physiological constraints. Furthermore, it has also been proposed that reduced soil water availability could promote nitrogen (N) limitation of European beech due to impaired microbial N cycling in soil, but this hypothesis has not yet been tested. Hence we investigated the influence of simulated climate change (increased temperatures, reduced soil water availability) on soil gross microbial N turnover and plant N uptake in the beech-soil interface of a typical mountainous beech forest stocking on calcareous soil in SW Germany. For this purpose, triple 15N isotope labelling of intact beech seedling-soil-microbe systems was combined with a space-for-time climate change experiment. We found that nitrate was the dominant N source for beech natural regeneration. Reduced soil water content caused a persistent decline of ammonia oxidizing bacteria and therefore, a massive attenuation of gross nitrification rates and nitrate availability in the soil. Consequently, nitrate and total N uptake of beech seedlings were strongly reduced so that impaired growth of beech seedlings was observed already after one year of exposure to simulated climatic change. We conclude that the N cycle in this ecosystem and here

  8. Climate Change Impairs Nitrogen Cycling in European Beech Forests

    Science.gov (United States)

    Dannenmann, Michael; Bilela, Silvija; Gasche, Rainer; Hanewinkel, Marc; Baltensweiler, Andri; Kögel-Knabner, Ingrid; Polle, Andrea; Schloter, Michael; Simon, Judy; Rennenberg, Heinz

    2016-01-01

    European beech forests growing on marginal calcareous soils have been proposed to be vulnerable to decreased soil water availability. This could result in a large-scale loss of ecological services and economical value in a changing climate. In order to evaluate the potential consequences of this drought-sensitivity, we investigated potential species range shifts for European beech forests on calcareous soil in the 21st century by statistical species range distribution modelling for present day and projected future climate conditions. We found a dramatic decline by 78% until 2080. Still the physiological or biogeochemical mechanisms underlying the drought sensitivity of European beech are largely unknown. Drought sensitivity of beech is commonly attributed to plant physiological constraints. Furthermore, it has also been proposed that reduced soil water availability could promote nitrogen (N) limitation of European beech due to impaired microbial N cycling in soil, but this hypothesis has not yet been tested. Hence we investigated the influence of simulated climate change (increased temperatures, reduced soil water availability) on soil gross microbial N turnover and plant N uptake in the beech-soil interface of a typical mountainous beech forest stocking on calcareous soil in SW Germany. For this purpose, triple 15N isotope labelling of intact beech seedling-soil-microbe systems was combined with a space-for-time climate change experiment. We found that nitrate was the dominant N source for beech natural regeneration. Reduced soil water content caused a persistent decline of ammonia oxidizing bacteria and therefore, a massive attenuation of gross nitrification rates and nitrate availability in the soil. Consequently, nitrate and total N uptake of beech seedlings were strongly reduced so that impaired growth of beech seedlings was observed already after one year of exposure to simulated climatic change. We conclude that the N cycle in this ecosystem and here

  9. Climate Change Impairs Nitrogen Cycling in European Beech Forests.

    Science.gov (United States)

    Dannenmann, Michael; Bimüller, Carolin; Gschwendtner, Silvia; Leberecht, Martin; Tejedor, Javier; Bilela, Silvija; Gasche, Rainer; Hanewinkel, Marc; Baltensweiler, Andri; Kögel-Knabner, Ingrid; Polle, Andrea; Schloter, Michael; Simon, Judy; Rennenberg, Heinz

    2016-01-01

    European beech forests growing on marginal calcareous soils have been proposed to be vulnerable to decreased soil water availability. This could result in a large-scale loss of ecological services and economical value in a changing climate. In order to evaluate the potential consequences of this drought-sensitivity, we investigated potential species range shifts for European beech forests on calcareous soil in the 21st century by statistical species range distribution modelling for present day and projected future climate conditions. We found a dramatic decline by 78% until 2080. Still the physiological or biogeochemical mechanisms underlying the drought sensitivity of European beech are largely unknown. Drought sensitivity of beech is commonly attributed to plant physiological constraints. Furthermore, it has also been proposed that reduced soil water availability could promote nitrogen (N) limitation of European beech due to impaired microbial N cycling in soil, but this hypothesis has not yet been tested. Hence we investigated the influence of simulated climate change (increased temperatures, reduced soil water availability) on soil gross microbial N turnover and plant N uptake in the beech-soil interface of a typical mountainous beech forest stocking on calcareous soil in SW Germany. For this purpose, triple 15N isotope labelling of intact beech seedling-soil-microbe systems was combined with a space-for-time climate change experiment. We found that nitrate was the dominant N source for beech natural regeneration. Reduced soil water content caused a persistent decline of ammonia oxidizing bacteria and therefore, a massive attenuation of gross nitrification rates and nitrate availability in the soil. Consequently, nitrate and total N uptake of beech seedlings were strongly reduced so that impaired growth of beech seedlings was observed already after one year of exposure to simulated climatic change. We conclude that the N cycle in this ecosystem and here

  10. Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L.) stand in south-eastern Germany based on repeated digital photographs

    OpenAIRE

    Menzel, Annette; Helm, Raimund; Zang, Christian

    2015-01-01

    Damage by late spring frost is a risk deciduous trees have to cope with in order to optimize the length of their growing season. The timing of spring phenological development plays a crucial role, not only at the species level, but also at the population and individual level, since fresh new leaves are especially vulnerable. For the pronounced late spring frost in May 2011 in Germany, we studied the individual leaf development of 35 deciduous trees (mainly European beech Fagus sylvatica L.) a...

  11. Some observations of slime moulds on wood and litter of beech forests

    OpenAIRE

    Dominika Ślusarczyk

    2013-01-01

    The results of research into slime moulds in beech forest reserves in Central Poland are discussed. Thirty species of slime moulds directly associated with beech wood and beech litter were recorded. Species associated with different decay phases of beech wood and litter were identified.

  12. Beech carbon productivity as driver of ectomycorrhizal abundance and diversity.

    Science.gov (United States)

    Druebert, Christine; Lang, Christa; Valtanen, Kerttu; Polle, Andrea

    2009-08-01

    We tested the hypothesis that carbon productivity of beech (Fagus sylvatica) controls ectomycorrhizal colonization, diversity and community structures. Carbon productivity was limited by long-term shading or by girdling. The trees were grown in compost soil to avoid nutrient deficiencies. Despite severe limitation in photosynthesis and biomass production by shading, the concentrations of carbohydrates in roots were unaffected by the light level. Shade-acclimated plants were only 10% and sun-acclimated plants were 74% colonized by ectomycorrhiza. EM diversity was higher on roots with high than at roots with low mycorrhizal colonization. Evenness was unaffected by any treatment. Low mycorrhizal colonization had no negative effects on plant mineral nutrition. In girdled plants mycorrhizal colonization and diversity were retained although (14)C-leaf feeding showed almost complete disruption of carbon transport from leaves to roots. Carbohydrate storage pools in roots decreased upon girdling. Our results show that plant carbon productivity was the reason for and not the result of high ectomycorrhizal diversity. We suggest that ectomycorrhiza can be supplied by two carbon routes: recent photosynthate and stored carbohydrates. Storage pools may be important for ectomycorrhizal survival when photoassimilates were unavailable, probably feeding preferentially less carbon demanding EM species as shifts in community composition were found. PMID:19344334

  13. Links between phenology and ecophysiology in a European beech forest

    Directory of Open Access Journals (Sweden)

    Urban J

    2015-08-01

    Full Text Available Over the course of a year, tree physiological processes are not only directly affected by environmental conditions, but also by the tree’s own phenological stages. At the same time, phenological stages should, to a certain degree, reflect tree physiology. However, we have rather poor knowledge of the details of the interplay between phenology and ecophysiology. The objective of this study was to develop a better understanding of the links between phenology and ecophysiology. We investigated the degree to which various physiological processes are synchronized both with each other and with phenology and what information related to phenology can be obtained from instrumental ecophysiological measurements. Phenological observations, along with measurements of transmittance of photosynthetically active radiation (PAR, stem volume changes, sap flow and xylogenesis were conducted in a 45-year old European beech (Fagus sylvatica stand in the Czech Republic. Results indicated that ecophysiology was tightly related with the phenological stage of the tree. Early spring phenological stages were closely linked with the beginning of cambial activity and the onset of sap flow, i.e., the first leaves were produced simultaneously with the beginning of stem radial growth. The highest xylem growth rates occurred in June, simultaneously with the highest sap flow rates. Cambial activity ceased with the onset of summer leaf coloring at the end of July, at the same time as the permanent decrease in sap flow rate. The end of cell wall maturation was linked to the onset of autumn leaf coloring. We conclude that instrumental measurements of tree and stand ecophysiology provided additional information better specifying the onset of particular phenostages. In our case, twelve permanently located sensors used to measure PAR transmittance captured leaf area development with acceptable accuracy, thus limiting the need for frequent visits to the forest site in the spring and

  14. Sap flow for beech (Fagus sylvatica L.) in a natural and a managed forest-effect of spatial heterogeneity

    DEFF Research Database (Denmark)

    Dalsgaard, Lise; Mikkelsen, Teis Nørgaard; Bastrup-Birk, Annemarie

    2011-01-01

    Beech (Fagus sylvatica L.) is an important species in natural and managed forests in Europe. This drought-sensitive species dominates even-aged stands as well more natural stands composed of a mixture of tree species, age and size classes. This study evaluates the extent that heterogeneity...... in spacing and tree diameter affect the seasonal availability and use of water. Two stands were evaluated: (i) a heterogeneous forest remnant (NAT) with trees up to similar to 300 years old, a mean top height of 28.4 m and a total of 733 stems ha(-1)with stem diameters averaging 18 cm and (ii) an even......(s-sum)) for trees growing in the evenly spaced MAN stand and trees in canopy and closed forest positions in NAT stand decreased as the availability of soil moisture was reduced. In the heterogeneous NAT stand, SWC in a recently formed canopy gap remained high throughout the vegetation period. Based on regression...

  15. Changes in the proteome of juvenile European beech following three years exposure to free-air elevated ozone

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    Kerner R

    2011-04-01

    Full Text Available Tropospheric ozone, one of the most phytotoxic air pollutants, may specially impose in long-lived forest trees substantial reduction in productivity and biomass. European beech saplings grown in lysimeter around areas were used to monitor proteomic changes upon elevated ozone concentrations following four vegetation periods of exposure. A proteome study based on highly sensitive two-dimensional fluorescence difference gel electrophoresis (2-D DIGE was performed to identify protein changes in European beech, the most important deciduous tree in Central Europe. Main emphasis was on identifying differentially expressed proteins after long-time period of ozone exposure under natural conditions rather than short-term responses or reactions under controlled conditions. Our results clearly demonstrate a response of European beech saplings to long-term ozone fumigation at the protein level. We indicate changes in the protein abundance of 142 protein spots; among them 59 were increased and 83 decreased following three years of elevated ozone exposure. As the first step, 40 proteins were identified by a homology driven mass spectrometric approach. Some of the identified proteins have been previously described in the context of short-term ozone responses in plants, indicating, at least for certain cellular functions, the congruence of plant reactions following short- and long-term ozone exposure. Under elevated ozone exposure, abundance of proteins related to the Calvin cycle and photosynthetic electron transport chain were decreased whereas the abundance of proteins regarding the carbon metabolism/catabolism were increased.

  16. Allocation of recent photoassimilates in mature European beech and Norway spruce - seasonal variability and responses to experimentally increased tropospheric O3 concentration and long-term drought

    Science.gov (United States)

    Grams, Thorsten

    2016-04-01

    This contribution summarizes a series of C allocation studies in maturing European beech and Norway spruce trees at Kranzberg Forest, located in southern Germany. Study objects are 60 to 70 year old trees, readily accessible via scaffoldings and canopy crane. Allocation of recently fixed photoassimilates is assessed either by conventional branch-bag labelling with 99 atom% 13CO2 or whole-tree labeling using 13C-depleted CO2 (isoFACE system). While labeling in branch bags, employed for few hours only, focused on phloem functionality in particular under long-term drought, C labeling of whole tree canopies was employed for up to 20 days, studying allocation of recent photoassimilates from the canopy along branches and stems to roots and soils below ground. In all experiments, dynamics of C allocation were mostly pursued assessing carbon isotopic composition of CO2 efflux from woody tissues which typically reflected isotopic composition of phloem sugars. Effects of severe and long-term summer drought are assessed in an ongoing experiment with roughly 100 trees assigned to a total of 12 plots (kroof.wzw.tum.de). Precipitation throughfall was completely excluded since early spring, resulting in pre-dawn leaf water potentials of both beech and spruce up to -2.2 MPa. The hypothesis was tested that long-term drought affects allocation of recently fixed C to branches and phloem functionality. In the annual course under unstressed conditions, phloem transport speed from the canopy to the stem (breast height) was double in beech compared to spruce, with highest transport velocities in early summer (about 0.51 and 0.26 m/h) and lowest in spring (0.26 and 0.12 m/h for beech and spruce, respectively). After leaf flush in spring, growth respiration of beech trunks was largely supplied by C stores. Recent photoassimilates supplied beech stem growth in early summer and refilled C stores in late summer, whereas seasonality was less pronounced in spruce. The hypothesis that growth

  17. Infectivity of Arbuscular Mycorrhizal Fungi in Naturally Regenerating, Unmanaged and Clear-Cut Beech Forests

    Institute of Scientific and Technical Information of China (English)

    I.CLOSA; N.GOICOECHEA

    2011-01-01

    Clear-cutting, a management practice applied to many beech forests in the North of Spain, modifies microclimate and, consequently,the composition of the understory plant community in the disturbed areas. The objectives of this study were to assess if changes in the understory vegetation caused by altered light microclimate after clear-cutting affect the infectivity of arbuscular mycorrhizal fungi (AMF) on herbaceous plant species in beech (Fagus sylvatica L.) forests naturally regenerating from clear-cutting and to test if the use of bioassays for studying the infectivity of native AMF could provide aseful information to improve the management of clear-cut areas.Three nearby beech forests in northwest Navarra, Spain, a region in the northwest part of the Pyrenees, were selected: an unmanaged forest, a forest clear-cut in 1996, and another forest clear-cut in 2001. High stem density in the forest clear-cut in 1996 (44 000 trees ha-1) attenuated photosynthetic active radiation (PAR) and impaired the growth of herbaceous species within the ecosystem. The percentage of AMF colonization of plants in bioassays performed on soil samples collected from the forest clear-cut in 1996 was always lower than 10%. In the forest clear-cut in 2001, where soil was covered by perennial grasses, PAR was high and thc infectivity of native AMF achieved minimum values in spring and autumn and a maximum value in summer. In contrast, the infectivity of native AMF in the umnanaged forest remained similar across the seasons. Our results demonstrated that changes in the composition of understory vegetation within beech forests strongly affected the infectivity of native AMF in clear-cut areas and suggested that the assessment of the infectivity of native AMF through bioassays could provide helpful information for planning either the removal of overstory when the tree density is so high that it impairs the correct development of herbaceous species or the plantation of new sesdlings when high

  18. State and silvicultural problems of beech forests in Northeast Serbia

    Directory of Open Access Journals (Sweden)

    Krstić Milun

    2002-01-01

    Full Text Available The state and silvicultural demands in beech forests of northeast Serbia were studied in the economic regions of Severni Kučaj, Timok and Južni Kučaj, and in the region of the National Park Đerdap. The detailed analysis of state forests was performed: representation of beech forests according to silvicultural form, origin, age structure, stand state and productivity Average volume in high beech forests of 218 m3 x ha–1 is for about 5% lower than the average in Serbia (207.2 m3 x ha–1, and it amounts to 87% of the optimal volume of beech forests in Serbia. Volume increment of 4.5 m3ha–1 is approximate to the average increment of high beech forests in Serbia, and it amounts to 75% of the optimal value. The average volume of coppice beech forests of 150 m3ha–1 is 60% of the optimal volume of beech forests in Serbia The age structure is unfavourable, because the percentage of well conserved mature stands is only about 8%. Unplanned regeneration has started on about 15% of the area. Middle-aged and maturing stands account for more than 3/4 of the total area (80%. Stand state of beech forests in this region can be assessed as close to unsatisfactory, if the criteria are conservation, origin, vitality, and also the health state Based on the above state, the concrete silvicultural demands for each silvicultural situation were determined and the silvicultural measures were proposed aiming at their rational utilisation and improvement of forest state: measures aiming at the establishment of new, quality stands and measures aiming at the improvement of the state of existing forests.

  19. Mapping beech ( Fagus sylvatica L.) forest structure with airborne hyperspectral imagery

    Science.gov (United States)

    Cho, Moses Azong; Skidmore, Andrew K.; Sobhan, Istiak

    2009-06-01

    Estimating forest structural attributes using multispectral remote sensing is challenging because of the saturation of multispectral indices at high canopy cover. The objective of this study was to assess the utility of hyperspectral data in estimating and mapping forest structural parameters including mean diameter-at-breast height (DBH), mean tree height and tree density of a closed canopy beech forest ( Fagus sylvatica L.). Airborne HyMap images and data on forest structural attributes were collected from the Majella National Park, Italy in July 2004. The predictive performances of vegetation indices (VI) derived from all possible two-band combinations (VI ( i, j) = ( Ri - Rj)/( Ri + Rj), where Ri and Rj = reflectance in any two bands) were evaluated using calibration ( n = 33) and test ( n = 20) data sets. The potential of partial least squares (PLS) regression, a multivariate technique involving several bands was also assessed. New VIs based on the contrast between reflectance in the red-edge shoulder (756-820 nm) and the water absorption feature centred at 1200 nm (1172-1320 nm) were found to show higher correlations with the forest structural parameters than standard VIs derived from NIR and visible reflectance (i.e. the normalised difference vegetation index, NDVI). PLS regression showed a slight improvement in estimating the beech forest structural attributes (prediction errors of 27.6%, 32.6% and 46.4% for mean DBH, height and tree density, respectively) compared to VIs using linear regression models (prediction errors of 27.8%, 35.8% and 48.3% for mean DBH, height and tree density, respectively). Mean DBH was the best predicted variable among the stand parameters (calibration R2 = 0.62 for an exponential model fit and standard error of prediction = 5.12 cm, i.e. 25% of the mean). The predicted map of mean DBH revealed high heterogeneity in the beech forest structure in the study area. The spatial variability of mean DBH occurs at less than 450 m. The DBH

  20. Seasonality and resource availability control bacterial and archaeal communities in soils of a temperate beech forest.

    Science.gov (United States)

    Rasche, Frank; Knapp, Daniela; Kaiser, Christina; Koranda, Marianne; Kitzler, Barbara; Zechmeister-Boltenstern, Sophie; Richter, Andreas; Sessitsch, Angela

    2011-03-01

    It was hypothesized that seasonality and resource availability altered through tree girdling were major determinants of the phylogenetic composition of the archaeal and bacterial community in a temperate beech forest soil. During a 2-year field experiment, involving girdling of beech trees to intercept the transfer of easily available carbon (C) from the canopy to roots, members of the dominant phylogenetic microbial phyla residing in top soils under girdled versus untreated control trees were monitored at bimonthly intervals through 16S rRNA gene-based terminal restriction fragment length polymorphism profiling and quantitative PCR analysis. Effects on nitrifying and denitrifying groups were assessed by measuring the abundances of nirS and nosZ genes as well as bacterial and archaeal amoA genes. Seasonal dynamics displayed by key phylogenetic and nitrogen (N) cycling functional groups were found to be tightly coupled with seasonal alterations in labile C and N pools as well as with variation in soil temperature and soil moisture. In particular, archaea and acidobacteria were highly responsive to soil nutritional and soil climatic changes associated with seasonality, indicating their high metabolic versatility and capability to adapt to environmental changes. For these phyla, significant interrelations with soil chemical and microbial process data were found suggesting their potential, but poorly described contribution to nitrification or denitrification in temperate forest soils. In conclusion, our extensive approach allowed us to get novel insights into effects of seasonality and resource availability on the microbial community, in particular on hitherto poorly studied bacterial phyla and functional groups.

  1. Effect of environmental variables and stand structure on ecosystem respiration components in a Mediterranean beech forest.

    Science.gov (United States)

    Guidolotti, Gabriele; Rey, Ana; D'Andrea, Ettore; Matteucci, Giorgio; De Angelis, Paolo

    2013-09-01

    The temporal variability of ecosystem respiration (RECO) has been reported to have important effects on the temporal variability of net ecosystem exchange, the net amount of carbon exchanged between an ecosystem and the atmosphere. However, our understanding of ecosystem respiration is rather limited compared with photosynthesis or gross primary productivity, particularly in Mediterranean montane ecosystems. In order to investigate how environmental variables and forest structure (tree classes) affect different respiration components and RECO in a Mediterranean beech forest, we measured soil, stem and leaf CO2 efflux rates with dynamic chambers and RECO by the eddy-covariance technique over 1 year (2007-2008). Ecosystem respiration showed marked seasonal variation, with the highest rates in spring and autumn and the lowest in summer. We found that the soil respiration (SR) was mainly controlled by soil water content below a threshold value of 0.2 m(3) m(-3), above which the soil temperature explained temporal variation in SR. Stem CO2 effluxes were influenced by air temperature and difference between tree classes with higher rates measured in dominant trees than in co-dominant ones. Leaf respiration (LR) varied significantly between the two canopy layers considered. Non-structural carbohydrates were a very good predictor of LR variability. We used these measurements to scale up respiration components to ecosystem respiration for the whole canopy and obtained cumulative amounts of carbon losses over the year. Based on the up-scaled chamber measurements, the relative contributions of soil, stem and leaves to the total annual CO2 efflux were: 56, 8 and 36%, respectively. These results confirm that SR is the main contributor of ecosystem respiration and provided an insight on the driving factors of respiration in Mediterranean montane beech forests. PMID:24044943

  2. Investigation of process of interception in beech-fir stand on mountain Goch

    Directory of Open Access Journals (Sweden)

    Ristić Ratko

    2002-01-01

    Full Text Available Part of the precipitation is intercepted by vegetation before reaching the ground. The portion of intercepted water, which is retained in storage of the vegetal cover and evaporates, is called the interception loss. Interception represents important component of water balance, because of reduction of total rainfall. It decreases potential for forming of surface runoff. Depends on complex of vegetative and climate factors. In humid forested regions about 25% of the annual precipitation may become interception loss. Results of investigation in beech-fir stand on mountain Goch are presented in this paper Investigation was carried out on experimental catchment area Vaona IV (A=0.098 km2, in association Abieti-fagetum, on mountain Goch, in Central Serbia. Standard rain gauges were used to determine total precipitation and throughfalls, during vegetation period (1992-1997. Total interception (Ic depends on total precipitation (Pb, kind of trees, shape and density of the crown, position in the stand and age. Average values of interception (Icsr during vegetation period (1992-1997, amount to Icsr=43.7-53.3% of total precipitation (fir, and Icsr=17.7-22.8% (beech.

  3. Ash recycling to spruce and beech stands effects on nutrients, growth, nitrogen dynamics and carbon balance; Askaaterfoering till gran- och bokbestaand - effekter paa naering, tillvaext, kvaevedynamik och kolbalans

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2006-03-15

    Ash recycling is an important part in a modern, sustainable forestry, especially in whole-tree harvest systems. Nutrients lost at harvest are returned to the forest with the wood-ash. In the project the effects of ash treatment on needle and leaf chemistry, tree growth, soil chemistry, soil water chemistry, and carbon and nitrogen dynamics were studied on 23 Norway spruce sites in south-western Sweden and in ten European beech sites in Scania, southern Sweden. On some of the sites there were previously established ash recycling experiments, but on a majority of the sites ash recycling was performed without experimental lay-out and ash and control plots were established afterwards. The most common dose was two tons of self hardened crushed wood-ash and two tons of Mg-lime. On average seven to eight years after ash recycling the results were 1. increased exchangeable stores of base cations in the soil in the beech and the spruce stands 2. increased base saturation in the beech and the spruce stands and increased BC/Al in the spruce stands 3. increased concentrations and ratios to N of P, Ca, Zn, and S in the needles, the increased P-values are especially important since P is close to or below deficiency levels in a majority of the spruce stands 4. decreased K-concentration in the beech leaves 5. increased tree growth with on average 14 % in the ash treated spruce stands compared to the control plots 6. increased carbon and nitrogen amounts in the biomass in the spruce stands 7. tendencies towards increased amounts of carbon and nitrogen in the soil in the beech stands and no effect in the soil in the spruce stands 8. increased concentrations of Ca, Mg, and SO{sub 4} and no effect on ANC in the soil water 9. no effect on potential net mineralization but increased potential nitrification rates 10. decreased concentration of nitrate in the soil water in the beech stands and no effect in the spruce stands 11. lower system N losses in the beech stands and possibly in the

  4. Height-Diameter Models for Mixed-Species Forests Consisting of Spruce, Fir, and Beech

    Directory of Open Access Journals (Sweden)

    Petráš Rudolf

    2014-06-01

    Full Text Available Height-diameter models define the general relationship between the tree height and diameter at each growth stage of the forest stand. This paper presents generalized height-diameter models for mixed-species forest stands consisting of Norway spruce (Picea abies Karst., Silver fir (Abies alba L., and European beech (Fagus sylvatica L. from Slovakia. The models were derived using two growth functions from the exponential family: the two-parameter Michailoff and three-parameter Korf functions. Generalized height-diameter functions must normally be constrained to pass through the mean stand diameter and height, and then the final growth model has only one or two parameters to be estimated. These “free” parameters are then expressed over the quadratic mean diameter, height and stand age and the final mathematical form of the model is obtained. The study material included 50 long-term experimental plots located in the Western Carpathians. The plots were established 40-50 years ago and have been repeatedly measured at 5 to 10-year intervals. The dataset includes 7,950 height measurements of spruce, 21,661 of fir and 5,794 of beech. As many as 9 regression models were derived for each species. Although the “goodness of fit” of all models showed that they were generally well suited for the data, the best results were obtained for silver fir. The coefficient of determination ranged from 0.946 to 0.948, RMSE (m was in the interval 1.94-1.97 and the bias (m was -0.031 to 0.063. Although slightly imprecise parameter estimation was established for spruce, the estimations of the regression parameters obtained for beech were quite less precise. The coefficient of determination for beech was 0.854-0.860, RMSE (m 2.67-2.72, and the bias (m ranged from -0.144 to -0.056. The majority of models using Korf’s formula produced slightly better estimations than Michailoff’s, and it proved immaterial which estimated parameter was fixed and which parameters

  5. Diversity and primary productivity of hill beech forests from Doftana Valley (Romanian Subcarpathians

    Directory of Open Access Journals (Sweden)

    Mihaela Paucã-Comãnescu

    2009-12-01

    Full Text Available The hill beech forests cover most of the woody area in the Doftana Valley. The present study refers, for the first time, to two beech forests typical to this belt, which belong to the phytocoenological associations Epipactieto-Fagetum (Resmeriţă, 1972, in the Lunca Mare area, and Hieracio rotundati-Fagetum (Vida 1983, Täuber 1987 in the Sotrile area, from floristic, structural, biomass and necromass accumulation point of view, within the framework of the vertical structure of biocoenosis. The limestone substratum, occasionally with small outcrops in the first beech forest, differs chiefly through the pH levels (6.34-5.67 from the siliceous substratum (pH 5.11-4.36 in the second beech forest. The layer of trees is dominated by Fagus sylvatica in both forests; this species is associated with Cerasus avium (4.5%, Acer pseudoplatanus (2% and Sorbus torminalis (2% in the first beech forest, and is monodominant in the second. Although the forest underwent selective cuts, more intense in the Lunca Mare area, the aboveground ligneous biomass reaches nowadays 222 t/ha in the Lunca Mare area compared to only 163 t/ha in the Sotrile area; the average height is 28.8ą2.49 m and 23.7ą1.12 m, respectively, and the diameter is 33.30ą7.9 cm and 31.60ą6.28 cm, respectively. The species of macrofungi, not very numerous during the study because of scarce precipitations (6 and 7 species, respectively, are predominant on the rhytidoma trees in the beech forest rooted on the limestone ground; in the Sotrile beech forest they are joined by mycorrhizal and parasite species. The layer of shrub is underdeveloped. The herbaceous layer is discontinuous, and includes, along herbs, small plants and saplings belonging to the ligneous species and to liana Hedera helix. The maximal value of the aboveground biomass of the layer is 317 kg/ha DM in the Lunca Mare area and 235 kg /ha DM in the Sotrile area. Bryophyta is present in large quantities, especially in the Sotrile

  6. Effects of ozone-induced stomatal closure on ozone uptake and its changes due to leaf age in sun and shade leaves of Siebold's beech

    OpenAIRE

    Hoshika, Yasutomo; Watanabe, Makoto; Inada, Naoki; KOIKE, Takayoshi

    2015-01-01

    An estimation of stomatal ozone uptake for the assessment of ozone risks in forest trees can be modified by ozone-induced stomatal closure. We thus examined a seasonal course of stomatal conductance in sun and shade leaves of Siebold's beech native to northern Japan (Fagus crenata) grown under free-air ozone exposure. A performance of multiplicative stomatal conductance model was also tested, when considering ozone-induced stomatal closure into the model. Ozone caused stomatal closure in both...

  7. Projected effects of climate change on the carbon stocks of European beech (Fagus sylvatica L. forests in Zala County, Hungary

    Directory of Open Access Journals (Sweden)

    Somogyi Zoltán

    2016-03-01

    Full Text Available Recent studies suggest that climate change will lead to the local extinction of many tree species from large areas during this century, affecting the functioning and ecosystem services of many forests. This study reports on projected carbon losses due to the assumed local climate change-driven extinction of European beech (Fagus sylvatica L. from Zala County, South-Western Hungary, where the species grows at the xeric limit of its distribution. The losses were calculated as a difference between carbon stocks in climate change scenarios assuming an exponentially increasing forest decline over time, and those in a baseline scenario assuming no climate change. In the climate change scenarios, three different sets of forest management adaptation measures were studied: (1 only harvesting damaged stands, (2 additionally salvaging dead trees that died due to climate change, and (3 replacing, at an increasing rate over time, beech with sessile oak (Quercus petraea Matt. Lieb. after final harvest. Projections were made using the open access carbon accounting model CASMOFOR based on modeling or assuming effects of climate change on mortality, tree growth, root-to-shoot ratio and decomposition rates. Results demonstrate that, if beech disappears from the region as projected by the end of the century, over 80% of above-ground biomass carbon, and over 60% of the carbon stocks of all pools (excluding soils of the forests will be lost by 2100. Such emission rates on large areas may have a discernible positive feedback on climate change, and can only partially be offset by the forest management adaptation measures.

  8. Structure and dynamics of a beech forest in a fully protected area in the northern Apennines (Sasso Fratino, Italy

    Directory of Open Access Journals (Sweden)

    Bianchi L

    2011-06-01

    Full Text Available Sasso Fratino Nature Reserve (National Park of Casentino Forests, northern Apennines is a quite rare example of natural Apennine forest. The Reserve was established in 1959, aiming to protect a forest, although not a virgin one, low-intensively disturbed in the past by comparison with other neighbouring stands. Causes of such a low disturbance are the very limited accessibility of the area due to the very steep slopes characterising the site morphology, as well as historical features. The forest is a pure beech stand from 1250 m a.s.l. upwards, below this altitude is a mixed beech and silver fir forest. The study focuses on the understanding of the processes driving the evolution of the forest in the absence of human activities. To achieve this goal, 9 permanent, long-term research plots were established at different altitudes, in order to investigate on forest dynamics and regeneration processes. Simplified (single-layer stand structures are more frequent where canopy gaps are absent. Two-layered structures are the result of the occurrence of canopy gaps, which allow the settlement, and subsequently the establishment, of a lower regeneration layer. Where the gap dimensions allow canopy closure, this kind of structure persists. When the gaps are quite large, the regeneration layer reaches the top layer and the structure stand tends, once more, toward a single-layer. Multilayered structures are extremely rare at plot level and become evident only at a wider scale. Our surveys indicate also a high variability of tree diameter distribution patterns in the forest stands. Such variability could be strictly related to the heterogeneity of site characteristics as well as to the effects of disturbance factors (both natural and anthropic. Concerning altitude, we observed an increase both of site index (dominant height and species diversity in the regeneration layer, moving from higher (1500 m to lower (900 m altitudes. As a whole, our observations show

  9. Competition for nitrogen between European beech and sycamore maple shifts in favour of beech with decreasing light availability.

    Science.gov (United States)

    Simon, Judy; Li, Xiuyuan; Rennenberg, Heinz

    2014-01-01

    Plant species use different strategies for maximizing growth and fitness under changing environmental conditions. At the ecosystem level, seedlings in particular compete with other vegetation components for light and nitrogen (N), which often constitute growth-limiting resources. In this study, we investigated the effect of light availability on the competition for N between seedlings of European beech and sycamore maple and analysed the consequences of this competition for the composition of N metabolites in fine roots. Our results show different strategies in N acquisition between beech and sycamore maple. Both species responded to reduced light availability by adapting their morphological and physiological traits with a decrease in biomass and net assimilation rate and an increase in specific leaf area and leaf area ratio. For beech seedlings, competition with sycamore maple led to a reduction in organic N uptake capacity. Reduced light availability led to a decrease in ammonium, but an increase in glutamine-N uptake capacity in sycamore maple. However, this response was stronger compared with that of beech and was accompanied by reduced growth. Thus, our results suggest better adaptation of N acquisition to reduced light availability in beech compared with sycamore maple seedlings.

  10. Flux-profile relationships over a fetch limited beech forest

    DEFF Research Database (Denmark)

    Dellwik, E.; Jensen, N.O.

    2005-01-01

    The influence of an internal boundary layer and a roughness sublayer on flux-profile relationships for momentum and sensible heat have been investigated for a closed beech forest canopy with limited fetch conditions. The influence was quantified by derivation of local scaling functions for sensible...... the canopy top for some wind sectors led to an increase in phi(m), a feature that has not previously been observed. For a fetch of 500 m over the beech forest during neutral atmospheric conditions, there is no height range at the site where profiles can be expected to be logarithmic with respect to the local...

  11. Beech bark necrosis: partition- ing the environmental and spatial variation of the damage severity in Central and South-Eastern Europe

    Directory of Open Access Journals (Sweden)

    Benjamín Jarčuška

    2013-12-01

    Full Text Available The beech bark necrosis (BBN infestation severity of European beech (Fagus sylvatica L. was assessed in regions of Central (CE and South-Eastern Europe (SE. Altogether more than 10,000 trees were sampled at 114 sites. Using variation partitioning method, we examined the pure and shared effects of stand, site, climate and spatial sets of variables on mean BBN severity. Our rating included (i the whole stand, (ii tree social status classes, (iii canopy (C and (iv understory (U trees separately. We found that C trees were less affected by BBN than sub-canopy and U trees in both regions. There were found inter-regional differences in amount of explained variability (25.4–73.9% for whole stand BBN and in the sensitivity of C and U trees to the environmental gradients. The analysis revealed that the climate and spatial variables followed by stand variables had the largest marginal effects on mean BBN severity in all models, while the site set of variables had the weakest one. More than half of the explained variation was shared among four sets of variables in SE, contrary to CE. Except to U trees in SE, the effect of climate – pure or spatially structured – remained the highest also after partitioning of variance; more in SE than in CE. Taking into account positive association between mean annual temperature and mean BBN severity in C trees in SE, reinforced negative effect of climate change on the necrosis might be expected to be more serious mainly in low situated beech forests there. Promoting the tree species diversity in forested areas with higher incidence of beech bark necrosis, i.e. in low altitudes in SE, could reduce the susceptibility of forests to the necrosis at regional level in the future. For better understanding of the relative importance of environmental and spatial variables on BBN severity, further research performed on finer spatial scale (extent and grain is necessary, along with accounting for pathogens involved in the

  12. The Effects of Exposure, Elevation and Tree Age on Seed Characteristics of Fagus orientalis Lipsky

    Directory of Open Access Journals (Sweden)

    Murat Ertekin

    2015-06-01

    Full Text Available Background and Purpose: Natural or artificial regeneration, rehabilitation, and conversion from coppice to high forest are important practices in Oriental beech (Fagus orientalis Lipsky forests in Turkey. Studies of the seeds of this species have increased in number because mast years are infrequent and seed germination is inhibited by dormancy. In this study we quantified the effects of tree age (40-59, 60-79 and 80-99 years, stand exposure (north, west, east and south and elevation (600 and 800 m a.s.l. on seed characteristics (germination, moisture content, and weight of Oriental beech. Material and Methods: The seeds used in this study were collected from natural beech forest at Kumluca, Bartin, in the western Black Sea region of Turkey. Experiments were carried out in the laboratory and the greenhouse of Bartin University. Results: Seed germination and moisture content varied significantly by elevation, and seed germination was strongly influenced by elevation. Moisture content was 14% at 600 m and 16% at 800 m. The effects of elevation and tree age on 100 seed weights were not significant but exposure had a significant effect. The highest 100 seed weight was recorded for trees on southern exposures and the highest germination percentage of 82% was recorded for trees on northern exposures. Conclusions: In conclusion, since oriental beech seedlings are produced by generative propagation method, seeds should be harvested in optimum distribution area of beech, from average ages and phenotypically plus tree.

  13. Experimental Study on Dry Torrefaction of Beech Wood

    NARCIS (Netherlands)

    Gucho, E.M.; Shahzad, K.; Bramer, E.A.; Akhtar, N.A.; Brem, G.

    2015-01-01

    Torrefaction is a thermochemical pre-treatment process for upgrading the properties of biomass to resemble those of fossil fuels such as coal. Biomass properties of particular interest are chemical composition, physical property and combustion characteristics. In this work, torrefaction of beech woo

  14. Experimental Study on Dry Torrefaction of Beech Wood and Miscanthus

    Directory of Open Access Journals (Sweden)

    Eyerusalem M. Gucho

    2015-05-01

    Full Text Available Torrefaction is a thermochemical pre-treatment process for upgrading the properties of biomass to resemble those of fossil fuels such as coal. Biomass properties of particular interest are chemical composition, physical property and combustion characteristics. In this work, torrefaction of beech wood and miscanthus (sinensis was carried out to study the influence of torrefaction temperature (240–300 °C and residence time (15–150 min on the aforementioned properties of the biomass. Results of the study revealed that torrefaction temperature has a significant influence on mass and energy yields, whereas the influence of the residence time becomes more apparent for the higher torrefaction temperatures (>280 °C. Torrefied miscanthus resulted in higher energy densification compared to beech wood for a residence time of 30 min. A significant improvement in grindability of the torrefied beech wood was obtained even for lightly torrefied beech wood (at 280 °C and 15 min of residence time. Observation from the combustion study showed that the ignition temperature is slightly affected by the torrefaction temperature. As a whole, the torrefaction temperature determines the characteristics of the torrefied fuel compared to other process parameters like residence time. Furthermore, with optimal process conditions, torrefaction produces a solid fuel with combustion reactivity and porosity comparable to raw biomass, whereas grindability and heating value are comparable to low quality coal.

  15. Species diversity and area-relationships in Danish beech forests

    NARCIS (Netherlands)

    Lawesson, J.E.; Blust, de G.; Grashof, C.; Firbanks, L.; Honnay, O.; Hermy, M.; Hobitz, P.; Jensen, L.M.

    1998-01-01

    The vascular flora of 62 Danish beech forests of eastern Jutland ranging in size from 1-445 ha, was investigated for species-area relations. Species richness reflecting total diversity, forest diversity, and of different habitat groups, were corrected for non-linearity by means of a log-log power fu

  16. The influence of the soil on spring and autumn phenology in European beech.

    Science.gov (United States)

    Arend, Matthias; Gessler, Arthur; Schaub, Marcus

    2016-01-01

    Tree phenology is a key discipline in forest ecology linking seasonal fluctuations of photoperiod and temperature with the annual development of buds, leaves and flowers. Temperature and photoperiod are commonly considered as main determinants of tree phenology while little is known about interactions with soil chemical characteristics. Seedlings of 12 European beech (Fagus sylvatica L.) provenances were transplanted in 2011 to model ecosystems and grown for 4 years on acidic or calcareous forest soil. Spring bud burst and autumnal leaf senescence were assessed in the last 2 years, 2013 and 2014, which were characterized by contrasting annual temperatures with a very warm spring and autumn in 2014. In 2013, spring bud burst and autumnal leaf senescence were advanced on acidic soil with a greater effect on leaf senescence. Hence, the vegetation period 2013 was shorter on this soil type compared with that on calcareous soil. In 2014, a similar soil effect was observed for spring bud burst while autumnal leaf senescence and the length of the vegetation period were not affected, probably due to interferences with the overall extension of the vegetation period in this exceptionally warm year. A different soil responsiveness was observed among the provenances with early bursting or senescing provenances being more sensitive than late bursting or senescing provenances. The findings of this study highlight the soil as an ecologically relevant factor in tree phenology and might help explain existing uncertainties in current phenology models. PMID:26420791

  17. The influence of the soil on spring and autumn phenology in European beech.

    Science.gov (United States)

    Arend, Matthias; Gessler, Arthur; Schaub, Marcus

    2016-01-01

    Tree phenology is a key discipline in forest ecology linking seasonal fluctuations of photoperiod and temperature with the annual development of buds, leaves and flowers. Temperature and photoperiod are commonly considered as main determinants of tree phenology while little is known about interactions with soil chemical characteristics. Seedlings of 12 European beech (Fagus sylvatica L.) provenances were transplanted in 2011 to model ecosystems and grown for 4 years on acidic or calcareous forest soil. Spring bud burst and autumnal leaf senescence were assessed in the last 2 years, 2013 and 2014, which were characterized by contrasting annual temperatures with a very warm spring and autumn in 2014. In 2013, spring bud burst and autumnal leaf senescence were advanced on acidic soil with a greater effect on leaf senescence. Hence, the vegetation period 2013 was shorter on this soil type compared with that on calcareous soil. In 2014, a similar soil effect was observed for spring bud burst while autumnal leaf senescence and the length of the vegetation period were not affected, probably due to interferences with the overall extension of the vegetation period in this exceptionally warm year. A different soil responsiveness was observed among the provenances with early bursting or senescing provenances being more sensitive than late bursting or senescing provenances. The findings of this study highlight the soil as an ecologically relevant factor in tree phenology and might help explain existing uncertainties in current phenology models.

  18. How adaptable is the hydraulic system of European beech in the face of climate change-related precipitation reduction?

    Science.gov (United States)

    Schuldt, Bernhard; Knutzen, Florian; Delzon, Sylvain; Jansen, Steven; Müller-Haubold, Hilmar; Burlett, Régis; Clough, Yann; Leuschner, Christoph

    2016-04-01

    Climate warming will increase the drought exposure of many forests world-wide. It is not well understood how trees adapt their hydraulic architecture to a long-term decrease in water availability. We examined 23 traits characterizing the hydraulic architecture and growth rate of branches and the dependent foliage of mature European beech (Fagus sylvatica) trees along a precipitation gradient (855-594 mm yr(-1) ) on uniform soil. A main goal was to identify traits that are associated with xylem efficiency, safety and growth. Our data demonstrate for the first time a linear increase in embolism resistance with climatic aridity (by 10%) across populations within a species. Simultaneously, vessel diameter declined by 7% and pit membrane thickness (Tm ) increased by 15%. Although specific conductivity did not change, leaf-specific conductivity declined by 40% with decreasing precipitation. Of eight plant traits commonly associated with embolism resistance, only vessel density in combination with pathway redundancy and Tm were related. We did not confirm the widely assumed trade-off between xylem safety and efficiency but obtained evidence in support of a positive relationship between hydraulic efficiency and growth. We conclude that the branch hydraulic system of beech has a distinct adaptive potential to respond to a precipitation reduction as a result of the environmental control of embolism resistance.

  19. Forest structure and woody plant species composition after a wildfire in beech forests in the north of Iran

    Institute of Scientific and Technical Information of China (English)

    Mohammad Naghi Adel; Hassan Pourbabaei; Ali Omidi; Daniel C Dey

    2013-01-01

    Beech (Fagus orientalis Lipsky) forest covers about 565,000 ha of land in Guilan province,north of Iran and forms a major carbon pool.It is an important economic,soil protection and recreation resource.We studied long-term effects of fire on the structure and composition 37 years after fire occurrence in these forests.To do this research,we selected 85 ha burned and 85 ha unbumed beech forests).The results indicated that the fire had not changed the overall uneven-aged structure,but it changed forest composition from pure stands to mixed stands that now include species such as Carpinus betulus,Acer cappadocicum and Alnus subcordata.The density of trees and regeneration was significantly increased,while the density of shrubs significantly decreased.The main reasons for increased tree regeneration were attributed to (1) reduction of litter depth,and (2) increase in available light from opening of the canopy and reduction in shrub competition.It is apparent that the forest is on a path to return to its natural state before the fire after 37 years.

  20. The influence of gap size on plant species diversity and composition in beech (Fagus orientalis forests, Ramsar, Mazandaran Province, North of Iran

    Directory of Open Access Journals (Sweden)

    MARZIEH BEGYOM-FAGHIR

    2013-10-01

    Full Text Available Pourbabaei H, Haddadi-Moghaddam H, Begyom-Faghir M, Abedi T. 2013. The influence of gap size on plant species diversity and composition in beech (Fagus orientalis forests, Ramsar, Mazandaran Province, North of Iran. Biodiversitas 14: 89-94.This study was conducted to investigate the influence of gap size on plant species diversity and composition in beech (Fagus orientalis Lipsky. forests, Ramsar, Mazandaran province. Fifteen gaps in small, medium, and large sizes were randomly selected. Abundance of tree saplings, shrubs and herbaceous species were counted on 4 m2 micro-plots within the gaps. Diversity indices including Shannon-Wiener, Simpson, Mc Arthur's N1, Hill's N2, species richness and Smith-Wilson’s evenness index were computed. The results revealed that there was significant difference among three gap categories in terms of diversity. The highest diversity values of tree and herbaceous species were obtained in the large gaps, while the highest diversity value of shrub species was in the medium gaps. Species composition of small gaps (28 species: 7 trees and 21 herbaceous, medium gaps (37 species: 7 trees, 5 shrubs and 25 herbaceous and large gaps (40 species: 7 trees, 4 shrubs and 29 herbaceous were recognized. Therefore, based on the results of this study, it is recommended that in order to maintain plant diversity and composition up to 400 m2 gap size cloud be used in this forests.

  1. Specific impacts of beech and Norway spruce on the structure and diversity of the rhizosphere and soil microbial communities.

    Science.gov (United States)

    Uroz, S; Oger, P; Tisserand, E; Cébron, A; Turpault, M-P; Buée, M; De Boer, W; Leveau, J H J; Frey-Klett, P

    2016-01-01

    The impacts of plant species on the microbial communities and physico-chemical characteristics of soil are well documented for many herbs, grasses and legumes but much less so for tree species. Here, we investigate by rRNA and ITS amplicon sequencing the diversity of microorganisms from the three domains of life (Archaea, Bacteria and Eukaryota:Fungi) in soil samples taken from the forest experimental site of Breuil-Chenue (France). We discovered significant differences in the abundance, composition and structure of the microbial communities associated with two phylogenetically distant tree species of the same age, deciduous European beech (Fagus sylvatica) and coniferous Norway spruce (Picea abies Karst), planted in the same soil. Our results suggest a significant effect of tree species on soil microbiota though in different ways for each of the three microbial groups. Fungal and archaeal community structures and compositions are mainly determined according to tree species, whereas bacterial communities differ to a great degree between rhizosphere and bulk soils, regardless of the tree species. These results were confirmed by quantitative PCR, which revealed significant enrichment of specific bacterial genera, such as Burkholderia and Collimonas, known for their ability to weather minerals within the tree root vicinity. PMID:27302652

  2. Herbicide Hardwood Crop Trees Release in Central West Virginia

    OpenAIRE

    Kochenderfer, Jeffrey Davis

    1999-01-01

    Repeated partial cutting in the Appalachian hardwood region has often favored the development of tolerant species like American beech (Fagus grandifolia Ehrh.) and stands with a high proportion of cull trees. Crop tree release is a widely recommended practice to improve species composition and growth rates in these unevenaged structured stands. Chemical control offers some distinct advantages from the standpoint of safety and residual stand damage, over mechani...

  3. Transfer Analysis of Provenance Trials Reveals Macroclimatic Adaptedness of European Beech (Fagus sylvatica L.

    Directory of Open Access Journals (Sweden)

    RASZTOVITS, Ervin

    2009-01-01

    Full Text Available The aim of the study was to analyse provenance tests of beech situated close to theSoutheastern-continental limits of the species, in order to develop a response model of adaptation andplasticity of populations on evolutionary-ecological basis, following sudden climatic changes as aresult of transplanting. Modelling of juvenile height was performed with the help of ecodistancevariables. The concept of transfer analysis and ecodistance is based on the hypothesis that phenotypicresponse to macroclimatic changes depends on the inherited adaptive potential of the population andon the magnitude and direction of experienced environmental change. In common garden experiments,the transfer to the planting site is interpreted as simulation of environmental change. The applicationof ecodistance of transfer for evaluating common garden experiments provides much neededquantitative information about response of tree populations to predicted climatic changes.The analysis of three field experiments of European beech in SE Europe invalidate earlier doubtsabout the existence of macroclimatic adaptation patterns in juvenile growth and justify restrictions ofuse of reproductive material on the basis of evolutionary ecology. The presented model illustrates thatresponse to climatic change is regionally divergent, depending on testing conditions and on hereditarytraits. In particular, climatic warming in the central-northern part of the range may lead to productionincrease. However, under the stressful and uncertain conditions at the lower (xeric limit of thespecies, growth depression and vitality loss are predicted. The deviating behaviour of higher elevationprovenances support their separate treatment.The results may be utilised in climate change adaptation and mitigation policy in forestry andnature conservation, to revise rules for use of reproductive material and also for validatingevolutionary and ecological hypotheses related to climate change effects.

  4. Comparison of the carbon stock in forest soil of sessile oak and beech forests

    Science.gov (United States)

    Horváth, Adrienn; Bene, Zsolt; Bidló, András

    2016-04-01

    Forest ecosystems are the most important carbon sinks. The forest soils play an important role in the global carbon cycle, because the global climate change or the increase of atmospheric CO2 level. We do not have enough data about the carbon stock of soils and its change due to human activities, which have similar value to carbon content of biomass. In our investigation we measured the carbon stock of soil in 10 stands of Quercus petraea and Fagus sylvatica. We took a 1.1 m soil column with soil borer and divided to 11 samples each column. The course organic and root residues were moved. After evaluation, we compared our results with other studies and the carbon stock of forests to each other. Naturally, the amount of SOC was the highest in the topsoil layers. However, we found significant difference between forest stands which stayed on the same homogenous bedrock, but very close to each other (e.g. distance was 1 or 2 km). We detected that different forest utilizations and tree species have an effect on the forest carbon as the litter as well (amount, composition). In summary, we found larger amount (99.1 C t/ha on average) of SOC in soil of stands, where sessile oak were the main stand-forming tree species. The amount of carbon was the least in turkey oak-sessile oak stands (85.4 C t/ha on average). We found the highest SOC (118.3 C t/ha) in the most mixed stand (silver lime-beech-red oak). In the future, it will be very important: How does climate change affect the spread of tree species or on carbon storage? Beech is more sensitive, but even sessile oak. These species are expected to replace with turkey oak, which is less sensitive to drought. Thus, it is possible in the future that we can expect to decrease of forest soil carbon stock capacity, which was confirmed by our experiment. Keywords: carbon sequestration, mitigation, Fagus sylvatica, Quercus petraea, litter Acknowledgements: Research is supported by the "Agroclimate.2" (VKSZ_12-1-2013-0034) EU

  5. SYNTAXOMOMICAL SURVEY O F EUROPEAN BEECH FORESTS: SOME GENERAL CONCLUSIONS

    Directory of Open Access Journals (Sweden)

    H. DIERSCHKE

    1997-01-01

    Full Text Available A short overwiev is given about the historical development of syntaxonomy of European beech forests. Different solutions of classification have been proposed, following more or less two main approaches: Division of alliances and suballiances by ecologically or geographically orientated species groups. A new classification of European beech forests is proposed with 8 (or more geographically orientated alliances, which can be further divided into suballiances by ecological species groups. For each alliance character and differential species, nomenclatural type and the area is mentioned, based on a (non puplished synthetic table, including 10.006 relevés from all parts of Europe. From this table also some overlapping species groups (a-n are given.

  6. Disintegration of beech wood char during thermal conversion

    DEFF Research Database (Denmark)

    Hindsgaul, Claus

    were limited by Knudsen diffusion through the pits in the wood cell walls for degrees of conversion by gasification up to at least 0.5. A computer model of slab gasification based on the diffusion measurements successfully predicted the mass loss rate during diffusion-limited gasification of beech wood......In the present work the processes occurring in the structures of slowly pyrolysed beech wood char during thermal gasification have been investigated. Emphasis was put on physical changes and gas transport properties during conversion. The highly anisotropic structure of wood was preserved in its...... char. Direct observation of the microscopic char structures during gasification in CO2 at 735 QC showed that the basic structure was nearly intact up to degrees of conversion of 0.6—0.7. Uni-axial measurements of diffusion coefficients and permeabilities with a Wicke-Kallenbach cell revealed...

  7. China's Beech Forests in the Pre-Quaternary

    Directory of Open Access Journals (Sweden)

    L. Yu-Sheng

    1998-01-01

    Full Text Available Fagus in China is never dominant in Late Cretaceous and Tertiary floras although it might reach its highest diversity in the Miocene. The genus Fagus was more widely distributed during the Palaeogene than in the Neogene. Furthermore, the ecological requirements of Fagus in the Palaeogene seem much broader than those in the Neogene onwards. This is because the Palaeogene floras containing Fagus lived in various conditions from an arid and hot climate to a humid and warm habitat. Additionally, Fagus then coexisted with many kinds of hygrophilous, thermophilous and xerophilous plants. However, the wide distribution, broad ecological adaptation and species composition changed greatly in the Neogene. The Neogene Fagus-containing floras are slightly more similar to the modern beech forests than the Palaeogene ones, although a big difference remains. Chinese fossil data document the post-Tertiary development of the modern beech forests. doi:10.1002/mmng.19980010111

  8. Structure and management of beech (Fagus sylvatica L.) forests in Italy

    OpenAIRE

    Nocentini S

    2009-01-01

    Beech forests characterise the landscape of many mountain areas in Italy, from the Alps to the southern regions. This paper analyses the relationship between stand structure and the management history of beech in Italy. The aim is to outline possible strategies for the sustainable management of these forest formations. The present structure of beech forests in Italy is the result of many interacting factors. According to the National Forest Inventory, more than half the total area covered by ...

  9. Influence of Climatic Type of Year on Beech and Scots Pine Eustress

    Science.gov (United States)

    Lyubenova, Mariyana; Chikalanov, Alexandre; van Bodegom, Peter; Kattge, Jens; Popova, Silvia; Zlateva, Plamena

    2016-04-01

    The present study deals with the relationships of climate types and the periods with low radial stem growth of black pine and beech locations in Europe. The identification of climatic types (CT) and eustress caused CT, their relative participation in the period of 1901-2009 by locations, the manifestation of main adverse type, led periodically to reduction of tree ring width, as well as the comparison of obtained types by precipitations and the SPI classes were the subjects of investigation. The analyses demonstrated that despite the local differences, the stress impact of dry and wet years, especially if they are accompanied by the cold or hot regimes, is well expressed. The successive changes of climate types at least two years before the eustress year are also relevant. The application of climatic types to study the relationship with trees eustress is more applicable when there are no large deviations in temperatures or precipitations by years and locations. The demonstrated holistic analyses are applicable for the forest areas monitoring and management. Key words Pinus sylvestris L., Fagus sylvatica L., climatic type, SPI, eustress, SPPAM application, SPI

  10. THE QUALITY OF THE SURFACE AT THE BEECH WOODTURNING

    Directory of Open Access Journals (Sweden)

    Mirela CHERCIU

    2015-05-01

    Full Text Available There have been experiments made with outside cylindrical beech woodturning with low cutting speed, and feed successively changed. We study, qualitative rather than quantitative, the roughnesss of the surface achieved. It interprets the appearance of each surface based on the theory of cutting considerations. Resulted surface images are given, photographed with a camera and microscope. It appears that here are no propellers generated by the cutting tool nose on the cylindrical part, excepting the situation of using high feeds.

  11. Dead trees in the virgin forest of Pečka

    OpenAIRE

    Debeljak, Marko

    1999-01-01

    This study treats dead trees and their remnants in the research areas of the Pe~ka virgin forest at a location of Abieti-Fagetum dinaricum. It covers four decaying stages: stump, mound, wood remnants, standing dead trees and their remnants. We first classify and describe the decaying stages, and define a manner of calculating their specific volume. We then compare the decaying stages, establishing regularities in the decaying process for the beech and the fir tree. Moreover, a quantitative co...

  12. Changes in susceptibility of beech (Fagus sylvatica) seedlings towards Phytophthora citricola under the influence of elevated atmospheric CO{sub 2} and nitrogen fertilization

    Energy Technology Data Exchange (ETDEWEB)

    Fleischmann, F., E-mail: fleischmann@wzw.tum.d [Phytopathology of Woody Plants, Technische Universitaet Muenchen, Am Hochanger 13, 85354 Freising (Germany); Raidl, S. [Department Biology I and GeoBioCenterLMU, Systematic Mycology, Ludwig Maximilians Universitaet Muenchen, Menzinger Strasse 67, 80638 Muenchen (Germany); Osswald, W.F. [Phytopathology of Woody Plants, Technische Universitaet Muenchen, Am Hochanger 13, 85354 Freising (Germany)

    2010-04-15

    The growth-differentiation balance hypothesis (GDBH) predicts changes in susceptibility of plants against herbivores with changing resource availability. In the presented study we tested the validity of the GDBH for trees infected with a root pathogen. For this purpose Fagus sylvatica seedlings grown under different atmospheric CO{sub 2}- and soil nitrogen regimes were infected with the root pathogen Phytophthora citricola. High nitrogen supply increased total biomass of beech regardless of the CO{sub 2}-treatment, whereas elevated CO{sub 2} enhanced biomass only in the high nitrogen treatment. The responses of beech under the different growing regimes to the Phytophthora root infection were not in line with the predictions of the GDBH. Enhanced susceptibility of beech against P. citricola was found in seedlings grown under elevated CO{sub 2} and low nitrogen supply. Fifteen months after inoculation these plants were characterized by enhanced water use efficiency, by altered root-shoot ratios, and by enhanced specific root tip densities. - Susceptibility of Fagus sylvatica to the root pathogen Phytophthora citricola increased under elevated CO{sub 2}

  13. Seasonal dynamics of δ(13) C of C-rich fractions from Picea abies (Norway spruce) and Fagus sylvatica (European beech) fine roots.

    Science.gov (United States)

    Paya, Alex M; Grams, Thorsten E E; Bauerle, Taryn L

    2016-09-01

    The (13/12) C ratio in plant roots is likely dynamic depending on root function (storage versus uptake), but to date, little is known about the effect of season and root order (an indicator of root function) on the isotopic composition of C-rich fractions in roots. To address this, we monitored the stable isotopic composition of one evergreen (Picea abies) and one deciduous (Fagus sylvatica), tree species' roots by measuring δ(13) C of bulk, respired and labile C, and starch from first/second and third/fourth order roots during spring and fall root production periods. In both species, root order differences in δ(13) C were observed in bulk organic matter, labile, and respired C fractions. Beech exhibited distinct seasonal trends in δ(13) C of respired C, while spruce did not. In fall, first/second order beech roots were significantly depleted in (13) C, whereas spruce roots were enriched compared to higher order roots. Species variation in δ (13) C of respired C may be partially explained by seasonal shifts from enriched to depleted C substrates in deciduous beech roots. Regardless of species identity, differences in stable C isotopic composition of at least two root order groupings (first/second, third/fourth) were apparent, and should hereafter be separated in belowground C-supply-chain inquiry. PMID:27155532

  14. Temporally resolved intra-annual wood density variations in European beech (Fagus sylvatica L. as affected by climate and aspect

    Directory of Open Access Journals (Sweden)

    Ernst van der Maaten

    2012-05-01

    Full Text Available We investigated the temporal variability of intra-annual wood density variations in European beech (Fagus sylvatica L. in a valley in southwestern Germany. Samples were collected from 11 beech trees growing at north-west (NW and south-west (SW exposed slopes. High-frequency densitometry was used to obtain wood density profiles. We converted radial positions within these profiles to a seasonal time scale over automatic point dendrometer data for the period 2001–2006. Temporally resolved wood density data was analyzed both visually and statistically, using correlation analysis and multiple linear regressions. Water availability was found to be of major importance for wood formation. Further, our results suggest that climatic forcing of wood density is not necessarily restricted to the late growing season only, but that strong associations may exist during a major part of the growing season. Combining wood property data with point dendrometer measurements was demonstrated to be valuable for increasing the understanding on the effects of changing environmental conditions on wood formation

  15. Temporally resolved intra-annual wood density variations in European beech (Fagus sylvatica L. as affected by climate and aspect

    Directory of Open Access Journals (Sweden)

    Ernst van der Maaten

    2012-06-01

    Full Text Available We investigated the temporal variability of intra-annual wood density variations in European beech (Fagus sylvatica L. in a valley in southwestern Germany. Samples were collected from 11 beech trees growing at north-west (NW and south-west (SW exposed slopes. High-frequency densitometry was used to obtain wood density profiles. We converted radial positions within these profiles to a seasonal time scale over automatic point dendrometer data for the period 2001-2006. Temporally resolved wood density data was analyzed both visually and statistically, using correlation analysis and multiple linear regressions. Water availability was found to be of major importance for wood formation. Further, our results suggest that climatic forcing of wood density is not necessarily restricted to the late growing season only, but that strong associations may exist during a major part of the growing season. Combining wood property data with point dendrometer measurements was demonstrated to be valuable for increasing the understanding on the effects of changing environmental conditions on wood formation.

  16. The Contribution of Managed and Unmanaged Forests to Climate Change Mitigation—A Model Approach at Stand Level for the Main Tree Species in Bavaria

    OpenAIRE

    Christoph Schulz; Markus Blaschke; Sebastian Höllerl; Daniel Klein

    2013-01-01

    Forestry-based carbon sequestration projects demand a comprehensive quantification of the different climate change mitigation effects. In our study, we modeled a life cycle of managed pure stands consisting of the four main tree species in Bavaria (spruce, pine, beech and oak). For spruce and beech, an unmanaged stand was additionally integrated in order to analyze the differences in climate change mitigation effects compared to the managed stands. We developed a climate change mitigation mod...

  17. The natural abundance of 15N in litter and soil profiles under six temperate tree species: N cycling depends on tree species traits and site fertility

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Nilsson, Lars Ola; Schmidt, Inger Kappel;

    2013-01-01

    for these N variables and for the litter δ15N and enrichment factor. Litter from ash and sycamore maple with high N status and low fungal mycelia activity was enriched in 15N (+0.9 delta units) relative to other tree species (European beech, pedunculate oak, lime and Norway spruce) even though the latter...

  18. Harvested wood products and carbon sink in a young beech high forest

    Directory of Open Access Journals (Sweden)

    Pilli R

    2008-03-01

    Full Text Available According to art. 3.4 of the Kyoto Protocol (KP, Italy has elected forest management as additional human-induced activity to attain the goal of reduction in greenhouse gas emissions. The whole forest area not subjected to afforestation, reforestation or deforestation processes since 1990 will be considered as managed forest. In order to analyse different management strategies, the Carbon-Pro Project, involving 9 partners of the European CADSES area, considered a young beech high forest (ex-coppice, defined as "transitory silvicultural system" as a common case study for the Pre-alps region. Using data collected with forest plans during the period 1983 - 2005, aboveground and belowground forest carbon stock and sink of a specific forest compartment were estimated by the Carbon Stock Method proposed by the IPCC Guidelines. In order to apply this approach 41 trees were cut and a species-specific allometric equation was developed. Considering the aboveground tree biomass, the carbon sink amounts to 1.99 and 1.84 Mg C ha-1 y-1 for the period 1983 - 1994 and 1994 - 2005 respectively. Adding the belowground tree biomass, the estimated sink amounts to 2.59 and 2.39 Mg C ha-1 y-1 for each period. Taking the harvested wood products (firewood, the total carbon sequestration during the second period is 0.16 Mg C ha-1 y-1. The case study highlights the possible rules for the different management strategies. In effect, the utilisation of the entire increase in aboveground biomass as firewood gives an energy substitution effect but, according to the Marrakesh Accords, it cannot be accounted for the KP. On the other hand, an accumulation strategy gives the maximum possible carbon absorption and retention.

  19. Arthropod diversity in pristine vs. managed beech forests in Transcarpathia (Western Ukraine

    Directory of Open Access Journals (Sweden)

    Vasyl Chumak

    2015-01-01

    We conclude that biodiversity in pristine beech forests is not generally higher than in managed beech forests. However, the much higher amount of dead wood in pristine forests provides a source habitat for saproxylic species spreading into managed forest plots in the same region, but not to distant forests, far from virgin forests, such as in Western Europe.

  20. Characterization of soil microarthropod communities in Italian beech forest

    Science.gov (United States)

    Conti, F. D.; Menta, C.; Piovesan, G.

    2009-04-01

    The contribution of soil organisms to ecosystem functions such as decomposition, nutrient recycling and the maintenance of physico-chemical properties is well recognised, as is the fact that soil fauna plays an important role in the formation and stabilisation of soil structure. The diversity of soil fauna includes a quarter of described living species, the majority of which are insects and arachnids. Soil fauna plays an essential role in forests and agro-ecosystems by maintaining their functionality and productivity. The aim of this study is to evaluate the biodiversity of soil microarthropods communities in different Italian beech forest. Particular attention is paid to the role of fossorial microarthropods in the maintenance of soil structure and in the organic matter movements. Three beech forests are studied, two located in the North and one in the Centre of Italy. Microarthropods are extracted from litter and soil with a Berlese-Tullgren funnel, identified to order level (class level for myriapods) and counted using a microscope. Relative order abundance and biodiversity are expressed using the Shannon-Weaver diversity index (H) and evenness index (J). Soil biological quality is expressed using the QBS-ar index and Acari/Collembola ratio. The results show a richness of microarthropods: several orders, till 19 different groups, are determined and identified. Acari and collembola are the main represented taxa and, especially in litter samples, pseudoscorpions, different specimens of diplopods (or millipedes) and chilopods (centipedes) are found. Thus the presence in particular of diplopods offers the possibility of studying fossorial microarthropods functions in detail. Furthermore, both in soil and in litter samples, adapted groups are recognized, such as pauropods, symphyla, proturans and diplurans, with specific morphological characteristics that these species suited to soil habitat. Therefore they attest a good level of soil quality and high natural value

  1. Nitrogen addition enhances drought sensitivity of young deciduous tree species

    Directory of Open Access Journals (Sweden)

    Christoph Dziedek

    2016-07-01

    Full Text Available Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N and drought (D effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii in relation to functional diverse species mixtures using data from a four-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e. combined treatment effects were non-additive, while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e. trait combination, but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role (‘trait portfolio’ that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they

  2. Nitrogen Addition Enhances Drought Sensitivity of Young Deciduous Tree Species.

    Science.gov (United States)

    Dziedek, Christoph; Härdtle, Werner; von Oheimb, Goddert; Fichtner, Andreas

    2016-01-01

    Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N) and drought (D) effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii) in relation to functional diverse species mixtures using data from a 4-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e., combined treatment effects were non-additive), while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e., trait combination), but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role ('trait portfolio') that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they provide further

  3. Ozone-induced stomatal sluggishness develops progressively in Siebold's beech (Fagus crenata)

    International Nuclear Information System (INIS)

    We investigated the effects of ozone and leaf senescence on steady-state stomatal conductance and stomatal response to light variation. Measurements were carried out in a free-air ozone exposure experiment on a representative deciduous broadleaved tree species in Japan (Fagus crenata). Both steady-state and dynamic stomatal response to light variation varied intrinsically with season due to leaf senescence. Ozone induced the decrease in steady-state leaf gas exchange and the sluggish stomatal closure progressively. These findings suggest that ozone reduces the ability of plants to adapt to a fluctuating light environment under natural conditions, and therefore impairs plant growth and ability to control water loss. - Highlights: ► We investigated the effects of ozone and leaf senescence on stomatal response to light variation. ► Measurements were carried out in a free-air ozone exposure experiment on Siebold's beech. ► Stomatal response to light variation varied intrinsically with season due to leaf senescence. ► Steady-state stomatal conductance was reduced under elevated ozone. ► Ozone increased time for stomatal closing and reduced light-saturated photosynthesis progressively. - Ozone progressively induces a sluggishness of stomatal light response.

  4. Divergent habitat filtering of root and soil fungal communities in temperate beech forests.

    Science.gov (United States)

    Goldmann, Kezia; Schröter, Kristina; Pena, Rodica; Schöning, Ingo; Schrumpf, Marion; Buscot, François; Polle, Andrea; Wubet, Tesfaye

    2016-01-01

    Distance decay, the general reduction in similarity of community composition with increasing geographical distance, is known as predictor of spatial variation and distribution patterns of organisms. However, changes in fungal communities along environmental gradients are little known. Here we show that distance decays of soil-inhabiting and root-associated fungal assemblages differ, and identify explanatory environmental variables. High-throughput sequencing analysis of fungal communities of beech-dominated forests at three study sites across Germany shows that root-associated fungi are recruited from the soil fungal community. However, distance decay is substantially weaker in the root-associated than in the soil community. Variance partitioning of factors contributing to the observed distance decay patterns support the hypothesis that host trees stabilize the composition of root-associated fungi communities, relative to soil communities. Thus, they not only have selective impacts on associated communities, but also buffer effects of changes in microclimatic and environmental variables that directly influence fungal community composition. PMID:27511465

  5. Divergent habitat filtering of root and soil fungal communities in temperate beech forests

    Science.gov (United States)

    Goldmann, Kezia; Schröter, Kristina; Pena, Rodica; Schöning, Ingo; Schrumpf, Marion; Buscot, François; Polle, Andrea; Wubet, Tesfaye

    2016-01-01

    Distance decay, the general reduction in similarity of community composition with increasing geographical distance, is known as predictor of spatial variation and distribution patterns of organisms. However, changes in fungal communities along environmental gradients are little known. Here we show that distance decays of soil-inhabiting and root-associated fungal assemblages differ, and identify explanatory environmental variables. High-throughput sequencing analysis of fungal communities of beech-dominated forests at three study sites across Germany shows that root-associated fungi are recruited from the soil fungal community. However, distance decay is substantially weaker in the root-associated than in the soil community. Variance partitioning of factors contributing to the observed distance decay patterns support the hypothesis that host trees stabilize the composition of root-associated fungi communities, relative to soil communities. Thus, they not only have selective impacts on associated communities, but also buffer effects of changes in microclimatic and environmental variables that directly influence fungal community composition. PMID:27511465

  6. Effect of tree species and soil properties on nutrient immobilization in the forest floor

    DEFF Research Database (Denmark)

    Raulund-Rasmussen, Karsten; Vejre, Henrik

    1995-01-01

    To investigate the effect of tree species and soil properties on organic matter accumulation and associated nutrients, an area-based sampling of the forest floor was carried out in a 28 years old species trial including Norway spruce, Douglas fir, beech, and common oak at two sites, a poor and sa...

  7. The yeast flora of some decaying mushrooms on trunks of living trees

    NARCIS (Netherlands)

    Middelhoven, W.J.

    2004-01-01

    Several ascomycetous and basidiomycetous yeasts were isolated from rotten mushrooms on the trunks of beech and tamarisk trees. One strain, identified as the novel species Cryptococcus allantoinivorans, assimilated allantoin as the sole carbon source. Phylogenetically it belongs to the C. laurentii c

  8. A slight recovery of soils from Acid Rain over the last three decades is not reflected in the macro nutrition of beech (Fagus sylvatica) at 97 forest stands of the Vienna Woods.

    Science.gov (United States)

    Berger, Torsten W; Türtscher, Selina; Berger, Pétra; Lindebner, Leopold

    2016-09-01

    Rigorous studies of recovery from soil acidification are rare. Hence, we resampled 97 old-growth beech stands in the Vienna Woods. This study exploits an extensive data set of soil (infiltration zone of stemflow and between trees area at different soil depths) and foliar chemistry from three decades ago. It was hypothesized that declining acidic deposition is reflected in soil and foliar chemistry. Top soil pH within the stemflow area increased significantly by 0.6 units in both H2O and KCl extracts from 1984 to 2012. Exchangeable Ca and Mg increased markedly in the stemflow area and to a lower extent in the top soil of the between trees area. Trends of declining base cations in the lower top soil were probably caused by mobilization of organic S and associated leaching with high amounts of sulfate. Contents of C, N and S decreased markedly in the stemflow area from 1984 to 2012, suggesting that mineralization rates of organic matter increased due to more favorable soil conditions. It is concluded that the top soil will continue to recover from acidic deposition. However, in the between trees areas and especially in deeper soil horizons recovery may be highly delayed. The beech trees of the Vienna Woods showed no sign of recovery from acidification although S deposition levels decreased. Release of historic S even increased foliar S contents. Base cation levels in the foliage declined but are still adequate for beech trees. Increasing N/nutrient ratios over time were considered not the result of marginally higher N foliar contents in 2012 but of diminishing nutrient uptake due to the decrease in ion concentration in soil solution. The mean foliar N/P ratio already increased to the alarming value of 31. Further nutritional imbalances will predispose trees to vitality loss. PMID:27344089

  9. Sapling herbivory, invertebrate herbivores and predators across a natural tree diversity gradient in Germany’s largest connected deciduous forest

    OpenAIRE

    Sobek, Stephanie; Scherber, Christoph; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2009-01-01

    Tree species-rich forests are hypothesised to be less susceptible to insect herbivores, but so far herbivory–diversity relationships have rarely been tested for tree saplings, and no such study has been published for deciduous forests in Central Europe. We expected that diverse tree communities reduce the probability of detection of host plants and increase abundance of predators, thereby reducing herbivory. We examined levels of herbivory suffered by beech (Fagus sylvatica L.) and maple sapl...

  10. Tree sets

    OpenAIRE

    Diestel, Reinhard

    2015-01-01

    We study an abstract notion of tree structure which generalizes tree-decompositions of graphs and matroids. Unlike tree-decompositions, which are too closely linked to graph-theoretical trees, these `tree sets' can provide a suitable formalization of tree structure also for infinite graphs, matroids, or set partitions, as well as for other discrete structures, such as order trees. In this first of two papers we introduce tree sets, establish their relation to graph and order trees, and show h...

  11. Evaluation and comparison of size-density relationships for pure even-aged stands of ash (Fraxinus excelsior L.), beech (Fagus silvatica L.), oak (Quercus petraea Liebl.), and sycamore maple (Acer pseudoplatanus L.)

    OpenAIRE

    Le Goff, Noël; Ottorini, Jean Marc; Ningre, Francois

    2011-01-01

    Size-density relationships define the maximum number of stems that even-aged stands of a given species can hold in relation to the mean size of trees. They are used to derive stand density measures and are useful tools used to control tree mortality. Size-density relationships were already available in France for beech and oak. The objective of this study was to extend these relations to younger development stages and test if specific relations are needed to be established for a set of specie...

  12. Dead wood characteristics influencing macrofungi species abundance and diversity in Caspian natural beech (Fagus orientalis Lipsky forests

    Directory of Open Access Journals (Sweden)

    Kiomars Sefidi

    2015-08-01

    Full Text Available Aim of study: This study aimed to examine the dead wood inhabiting macrofungi communities occurring on dead beech and hornbeam trees in Caspian forests. Area of study: The Kheiroud forest in the north of Iran. Material and Methods: Data from 205 sampling dead tree were analyzed by means of Generalized Linear Models (GLM to test the effects of decay stage, DBH, Length or Height on macrofungi diversity. Additionally, tree species, dead wood size, log position, decay stage were used as predictor factors for the number of sporocarps species (NSS as a fungal species richness and diversity in each dead log using analysis of variance Main results: The number of sporocarps species (NSS varied in different dead wood size and decay classes. The different stages of decay and the different size classes of dead wood had significantly different species richness of macrofungi. Deadwood in the high-decayed stages contained the highest diversity of fungi. Most of fungi identified on both logs and snags belonged to Basidiomycetes and Ascomycetes. The highest value for richness and evenness indices calculated in large diameter dead wood in decay class III. The results indicated the size and decay class of dead wood describe the greatest variance of the model that means the highest number of sporocarps species inhabited on the large dead wood in advanced stage of decaying. Research highlights: Macrofungi diversity varied significantly across pieces of dead wood with downed logs, larger pieces, and wood in later stages of decay having the highest macrofungi diversity.

  13. Belowground carbon trade among tall forest trees

    Science.gov (United States)

    Klein, Tamir; Siegwolf, Rolf; Koerner, Christian

    2016-04-01

    Just imagine one tree could hand over large quantities of carbon to another tree. How would that change our thinking about carbon relations of forests, the single biggest biological C reservoir on earth? If such a tree-to-tree C shuttle would exist, it required a demand-supply gradient and a pipeline. Here we show that exactly this unthinkable does occur in overlapping root spheres of tall trees in a mixed temperate forest. Using canopy scale stable carbon isotope labelling applied from a construction crane, we demonstrate that carbon assimilated by spruce is traded over to neighbouring beech, larch, and pine in amounts so large that fine roots almost equilibrate the carbon source signature. The isotope mixing ratio indicated that the interspecific transfer accounted for 40% of the fine root carbon, which is ca. 280 kg ha-1 a-1. This is the first forest scale evidence of a large flux of carbon among mature trees from evolutionary distant taxa. Carbon transfer most likely occurred through common ectomycorrhiza networks, which also exhibited the labelled carbon signal. These observations indicate that while competition for resources (e.g. light, water, nutrients) is often considered the dominant tree-tree interaction in a forest, trees actually interact in more complex pathways including a massive carbon exchange.

  14. Frost Crack Impact on European Beech (Fagus sylvatica L.) Wood Quality

    OpenAIRE

    Vasile R. CÂMPU; Radu DUMITRACHE

    2015-01-01

    Frost crack represents one of the main defects which affect European beech wood quality. Therefore, the purpose of this paper is to improve the knowledge regarding both the impact of frost crack on European beech wood quality and the frost crack characteristics which affect wood quality. In order to do this, nineteen European beech trunks with frost crack have been studied. Each trunk has been cross-cut every 1 meter and the characteristics of frost crack and frost crack star-shaped heart hav...

  15. Similar net ecosystem exchange of beech stands located in France and Denmark

    DEFF Research Database (Denmark)

    Granier, A.; Pilegaard, K.; Jensen, N.O.

    2002-01-01

    Net ecosystem exchange (NEE), as measured with eddy covariance was compared for two European beech stands for the years 1996-1999: a young beech forest (32 year-old) growing in east France, and a mature beech stand (80 year-old) located in Denmark. Those sites are included in the Carboeuroflux/Ca......, explaining carbon uptake being significantly lower at the Danish than at the French site. If it exists, an age effect could not be detected in this comparison. (C) 2002 Elsevier Science B.V. All rights reserved....

  16. Tree species mapping by combining hyperspectral with LiDAR data

    OpenAIRE

    KEMPENEERS Pieter; Vancoillie, Friedl; Liao, Wenzhi; Devriendt, Flore; Vandekerkhove, Kris

    2014-01-01

    This study deals with data fusion of hyperspectral and LiDAR sensors for forest applications. In particular, the added value of different data sources on tree species mapping has been analyzed. A total of seven species have been mapped for a forested area in Belgium: Beech, Ash, Larch, Poplar, Copper beech, Chestnut and Oak. Hyperspectral data is obtained from the APEX sensor in 286 spectral bands. LiDAR data has been acquired with a TopoSys sensor Harrier 56 at full waveform. Confirming previ...

  17. Belowground carbon trade among tall trees in a temperate forest.

    Science.gov (United States)

    Klein, Tamir; Siegwolf, Rolf T W; Körner, Christian

    2016-04-15

    Forest trees compete for light and soil resources, but photoassimilates, once produced in the foliage, are not considered to be exchanged between individuals. Applying stable carbon isotope labeling at the canopy scale, we show that carbon assimilated by 40-meter-tall spruce is traded over to neighboring beech, larch, and pine via overlapping root spheres. Isotope mixing signals indicate that the interspecific, bidirectional transfer, assisted by common ectomycorrhiza networks, accounted for 40% of the fine root carbon (about 280 kilograms per hectare per year tree-to-tree transfer). Although competition for resources is commonly considered as the dominant tree-to-tree interaction in forests, trees may interact in more complex ways, including substantial carbon exchange. PMID:27081070

  18. Belowground carbon trade among tall trees in a temperate forest.

    Science.gov (United States)

    Klein, Tamir; Siegwolf, Rolf T W; Körner, Christian

    2016-04-15

    Forest trees compete for light and soil resources, but photoassimilates, once produced in the foliage, are not considered to be exchanged between individuals. Applying stable carbon isotope labeling at the canopy scale, we show that carbon assimilated by 40-meter-tall spruce is traded over to neighboring beech, larch, and pine via overlapping root spheres. Isotope mixing signals indicate that the interspecific, bidirectional transfer, assisted by common ectomycorrhiza networks, accounted for 40% of the fine root carbon (about 280 kilograms per hectare per year tree-to-tree transfer). Although competition for resources is commonly considered as the dominant tree-to-tree interaction in forests, trees may interact in more complex ways, including substantial carbon exchange.

  19. An index of structural complexity for Apennine beech forests

    Directory of Open Access Journals (Sweden)

    Sabatini FM

    2015-06-01

    Full Text Available A broad interest exists in developing structure-based indicators to use as proxies for other attributes that are difficult to assess, such as biological diversity. Summary variables that account for stand-scale forest structural complexity could facilitate the comparison among stands and provide a means of ranking stands in terms of their potential contribution to biodiversity. We developed an index of structural heterogeneity (SHI for beech forests in southern Italy: (i we established a preliminary list of 23 structural variables obtained from data routinely collected in forest inventories; (ii we quantified these variables in a set of 64 beech-dominated stands encompassing a wide range of variability in the Cilento, Vallo di Diano and Alburni National Park; (iii we identified a core set of attributes that take into account the main sources of structural he­terogeneity identified in reference old-growth forests; and (iv we combined these core attributes into a simple additive index (SHI. We identified eight core attributes that were rescaled to the range 0 to 10 using regression equations based on raw attribute data. The SHI was calculated as the sum of these attribute scores and then expressed as a percentage. The index performance was evaluated against ten reference old-growth beech stands in the Apennines. The index ranged between 38 and 79.1 (median=59.4 and was distri­buted normally for the calibration dataset. The SHI successfully discriminated between old-growth (range=71.9-99.9, median=85.1 and early-mature to mature forests. Furthermore, the SHI linearly increased with stand age and was higher in multi-layer high forests than in single- and double-layer forests. However, a large variation was detected within both management types and age classes. SHI could be helpful for foresters as a tool for quantifying and compa­ring structural heterogeneity before and after a silvicultural intervention ai­med at restoring the structural

  20. Rainfall interception by an evergreen beech forest, Nelson, New Zealand

    Science.gov (United States)

    Rowe, L. K.

    1983-10-01

    Throughfall under a beech ( Nothofagus) forest canopy at Donald Creek, Nelson, averaged 69% of the rain falling on the canopy, i.e. 1060 mm of 1530 mm in a year of normal rainfall. Using an estimate for stemflow at 2% of gross rainfall, interception loss averaged 29% of the annual rainfall, or 440 mm yr. -1. Seasonal differences in interception loss were significant, ranging from 22% in winter to 35% in summer, and resulted from seasonal variation in evaporation rates from a wet canopy. Seasonal variation in rainfall rate was slight. Four models, storm linear regression, monthly linear regression, sine curve and Gash's analytical model, were tested by comparison of predicted and observed interception. All gave very satisfactory estimates (< 10% error) and tended to slightly underestimate the measured interception loss.

  1. Coagulation-flocculation of beech condensate: particles size distribution.

    Science.gov (United States)

    Irmouli, Mohammed; Haluk, Jean Pierre

    2002-05-01

    Beech wood (Fagus sylvatica L.) condensate from a steaming operation was studied. The objective of our work was to study the precipitation of these wood extracts in presence of calcium ion after autoxidation at basic pH (8). The autoxidation was carried out at 250 rpm for 30 min, and flocculation was followed up for 30 min. An investigation with a laser sizer Mastersizer of Malvern has been done in order to study the influence of the agitation on the state of aggregation of the condensate. A negative correlation was observed between the mean size of particles and the agitation rate. Without stirring, flocculation rapidly occurred and the mean size of particles was high. Calcium-induced aggregation of the condensate was also found to be reversible toward agitation. PMID:16290593

  2. Priority effects during fungal community establishment in beech wood.

    Science.gov (United States)

    Hiscox, Jennifer; Savoury, Melanie; Müller, Carsten T; Lindahl, Björn D; Rogers, Hilary J; Boddy, Lynne

    2015-10-01

    Assembly history of fungal communities has a crucial role in the decomposition of woody resources, and hence nutrient cycling and ecosystem function. However, it has not been clearly determined whether the fungal species that arrive first may, potentially, dictate the subsequent pathway of community development, that is, whether there is a priority effect at the species level. We used traditional culture-based techniques coupled with sequencing of amplified genetic markers to profile the fungal communities in beech (Fagus sylvatica) disks that had been pre-colonised separately with nine species from various stages of fungal succession. Clear differences in community composition were evident following pre-colonisation by different species with three distinct successor communities identified, indicating that individual species may have pivotal effects in driving assembly history. Priority effects may be linked to biochemical alteration of the resource and combative ability of the predecessor. PMID:25798754

  3. Climatic Triggers of Extremes in Daily Beech, Oak and Pine Stem Diameter Growth and Shrinkage in Northeastern Germany: An Event Coincidence Analysis

    Science.gov (United States)

    Siegmund, Jonatan; Sanders, Tanja; Heinrich, Ingo; Helle, Gerd; Donner, Reik

    2016-04-01

    Observed recent and expected future increases in frequency and intensity of climatic extremes in central Europe may pose critical challenges for domestic tree species. Continuous dendrometer recordings provide a valuable source of information on tree stem diameter growth and shrinkage, offering the possibility to study a tree's response to environmental influences at a high temporal resolution. In this study, we analyze stem diameter variations of three domestic tree species (beech, oak and pine) from 2012-2014. We use the novel statistical approach of event coincidence analysis (ECA) to investigate the simultaneous occurrence of extreme daily weather conditions and extreme daily stem variations, using a 60-days sliding window analysis covering the full growth period of each year. Besides defining extreme events based on individual meteorological variables, we test 105 different combinations of variables regarding their impact on tree growth and shrinkage, postulating conditional event coincidence analysis as a new extension of the original methodology. Our results reveal a strong susceptibility of all three species to extremes in several meteorological variables. Yet, the intra-species differences are comparatively low. The obtained results provide a thorough extension of previous correlation-based studies by emphasizing on the timings of climatic extremes only.We suggest that the employed methodological approach should be further promoted in forest research regarding the investigation of tree responses to changing environmental conditions.

  4. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield

    Science.gov (United States)

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0–14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ13C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ13C, both hydraulic efficiency and embolism resistance were

  5. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield.

    Science.gov (United States)

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0-14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ(13)C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ(13)C, both hydraulic efficiency and embolism resistance were

  6. Intraspecific Variation in Wood Anatomical, Hydraulic, and Foliar Traits in Ten European Beech Provenances Differing in Growth Yield.

    Science.gov (United States)

    Hajek, Peter; Kurjak, Daniel; von Wühlisch, Georg; Delzon, Sylvain; Schuldt, Bernhard

    2016-01-01

    In angiosperms, many studies have described the inter-specific variability of hydraulic-related traits and little is known at the intra-specific level. This information is however mandatory to assess the adaptive capacities of tree populations in the context of increasing drought frequency and severity. Ten 20-year old European beech (Fagus sylvatica L.) provenances representing the entire distribution range throughout Europe and differing significantly in aboveground biomass increment (ABI) by a factor of up to four were investigated for branch wood anatomical, hydraulic, and foliar traits in a provenance trial located in Northern Europe. We quantified to which extend xylem hydraulic and leaf traits are under genetic control and tested whether the xylem hydraulic properties (hydraulic efficiency and safety) trades off with yield and wood anatomical and leaf traits. Our results showed that only three out of 22 investigated ecophysiological traits showed significant genetic differentiations between provenances, namely vessel density (VD), the xylem pressure causing 88% loss of hydraulic conductance and mean leaf size. Depending of the ecophysiological traits measured, genetic differentiation between populations explained 0-14% of total phenotypic variation, while intra-population variability was higher than inter-population variability. Most wood anatomical traits and some foliar traits were additionally related to the climate of provenance origin. The lumen to sapwood area ratio, vessel diameter, theoretical specific conductivity and theoretical leaf-specific conductivity as well as the C:N-ratio increased with climatic aridity at the place of origin while the carbon isotope signature (δ(13)C) decreased. Contrary to our assumption, none of the wood anatomical traits were related to embolism resistance but were strong determinants of hydraulic efficiency. Although ABI was associated with both VD and δ(13)C, both hydraulic efficiency and embolism resistance were

  7. Nematode communities of natural and managed beech forests - a pilot study

    DEFF Research Database (Denmark)

    Strandmark, Lisa Bjørnlund; Madsen, Mette Vestergård; Johansson, Sanne;

    2002-01-01

    was found in a Canonical Community Ordination (CANOCO) that related nematode data and various soil parameters in each sample. Beech forests of Mid-Zealand (Suserup) had significantly lower sand content, higher pH, higher PPI and higher nematode diversity according to the Shannon-index than the forests......The soil nematode communities of natural beech forests and managed beech forests were surveyed in order to examine which community parameters, if any, would be suited to differentiate between the two management regimes. Nematodes were collected from mineral soil at three sites, each including...... managed and adjacent natural beech forests. Following enumeration and identification of nematodes to family level, relative abundance of trophic groups, adult/juvenile ratio, Shannon-index, Plant Parasitic Index (PPI) and Maturity Index (MI) were determined. A clear separation of samples according to site...

  8. Morphological and physiological damages of the mycorrhiza-root-system of the beech, due to soil contamination and possibilities of regeneration. Morphologische und physiologische Schaedigungen des Mykorrhiza-Wurzel-Systems bei der Buche als Folge von Bodenbelastungen und Moeglichkeiten der Regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Heumann, H.G.; Hofmann, H.P.; Kubach, D.; Linert, U.

    1989-08-01

    Field and laboratory examinations were carried out in order to find out whether mycorrhizae of beeches are damaged by acid deposits or experimental changes of the substrate. The examined samples of mycorrhizae collected from areas of severely damaged beeches and from areas of undamaged beeches showed no significant correlation to the visible damage of trees in respect to frequency, vitality or structural organization. Laboratory experiments for artificial mycorrhizal formation of beech seedlings with Cenococcum geophilum in sloping plastic plate cultures and in a vermiculite/peat/sand substrate were successful. Metal treatments reduced shoot and root weights, whereby copper and nickel effected the mycorrhizal seedlings more than the non-mycorrhizal ones. Cytological examinations revealed that in the damaged plants cortical root cells are often destroyed by intracellular infections of C. geophilum. Our findings show that the positive effect of ectomycorrhizae on metal tolerance of trees cannot be generalized with respect to either metal, or fungal symbiont. (orig.) With 34 refs., 8 tabs., 62 figs.

  9. Structure and management of beech (Fagus sylvatica L. forests in Italy

    Directory of Open Access Journals (Sweden)

    Nocentini S

    2009-06-01

    Full Text Available Beech forests characterise the landscape of many mountain areas in Italy, from the Alps to the southern regions. This paper analyses the relationship between stand structure and the management history of beech in Italy. The aim is to outline possible strategies for the sustainable management of these forest formations. The present structure of beech forests in Italy is the result of many interacting factors. According to the National Forest Inventory, more than half the total area covered by beech has a long history of coppicing. High forests cover 34% of the total beech area and 13% have complex structures which have not been classified in regular types. Coppices are very widespread mainly because of the past, but also present importance of firewood and charcoal for mountain populations. A particular type of beech coppice, the selection coppice (or uneven aged coppice, was traditional in Tuscany and in some alpine areas. Starting from the fifties, following the widespread use of other low cost energy sources and the depopulation of mountain areas, many beech coppices have been progressively abandoned. Forest policies have been increasingly directed to favouring beech coppice conversion to high forests, which are considered more productive and ecologically more functional. Beech high forests have a very interesting management history which is a very good example of the separation between classical forest management, i.e., forest management systems defined by “scientific forestry”, described in text books and usually prescribed in forest regulation plans, and real life forest management, i.e., how forests have been, and mostly still are, actually managed. The analysis of the management history of beech high forests in Italy shows that management systems which favour simplified stand structure and composition according to rigid, predetermined models have been rarely applied. However, the traditional silviculture of beech stands in Southern

  10. Juvenile growth response of European beech (Fagus sylvatica L. to sudden change of climatic environment in SE European trials

    Directory of Open Access Journals (Sweden)

    Rasztovits E

    2009-12-01

    Full Text Available The aim of the study was to analyse provenance tests of beech situated close to the south-eastern continental limits of the species, in order to develop a response model of adaptation and plasticity of populations on evolutionary-ecological basis, following sudden climatic changes, as a result of transplanting. Modelling of juvenile height was performed with the help of ecodistance variables. The concept of transfer analysis and ecodistance is based on the hypothesis that phenotypic response to macroclimatic changes depends on the inherited adaptive potential of the population and on the magnitude and direction of experienced environmental change. In common garden experiments, the transfer to the planting site is interpreted as simulation of environmental change. The application of ecodistance of transfer for evaluating common garden experiments provides much needed quantitative information about response of tree populations to predicted climatic changes. The analysis of three field experiments of European beech in SE Europe indicates that macroclimatic adaptation patterns exist in juvenile growth and justify restrictions of use of reproductive material on the basis of evolutionary ecology. The presented model illustrates that response to climatic change is regionally divergent, depending on testing conditions and on hereditary traits. In particular, climatic warming in the central-northern part of the range may lead to production increase. However, under the stressful and uncertain conditions at the lower (xeric limit of the species, growth depression and vitality loss are predicted. The deviating behaviour of higher elevation provenances support their separate treatment. The results may be utilised in climate change adaptation and mitigation policy in forestry and nature conservation, to revise rules for use of reproductive material and also for validating evolutionary and ecological hypotheses related to climate change effects.

  11. Macromycetes of beech forests within the eastern part of the Fagus area in Europe

    Directory of Open Access Journals (Sweden)

    Maria Lisiewska

    2014-11-01

    Full Text Available This work presents the author's view on the habitat if individual forest communities based on the fungi she has collected and gives a comparison of the mycoflora of beech forest in Poland and in south and central Europe. The beech forest were studied by the phytosociological method. Fruit bodies occurring on the soil, in the litter and on rotten wood were studied.

  12. Comparison of Physical Properties of Untreated and Heat Treated Beech and Hornbeam

    Directory of Open Access Journals (Sweden)

    Tomislav Sinković

    2011-12-01

    Full Text Available The investigation of physical properties of heat treated beech wood and hornbeam wood found that their average value is lower and significantly different from average values of physical properties of untreated beech wood and hornbeam wood. The average value of density in absolutely dry condition of heat treated beech wood is smaller by 8.5% from the untreated, and the hornbeam wood is smaller by 7.5%. Reduction of average values of maximum shrinkage of heat treated beech wood and hornbeam wood is even bigger in relation to the untreated wood. Maximum radial shrinkage of heat treated beech wood is smaller by 7%, maximum tangential shrinkage by 23.5% and maximum volumetric shrinkage by 19.3% compared to the same physical properties of untreated beech wood. Heat treated hornbeam wood has an average value of maximum radial shrinkage smaller by 123%, maximum tangential shrinkage by 86% and maximum volume shrinkage by 99.5% compared to the same physical properties of untreated hornbeam wood. With such reduction in the maximum shrinkage in radial and tangential direction using heat treatment, hornbeam becomes particulary suitable for making products where dimensional stability is important.

  13. Occurrence and spatial pattern of water repellency in a beech forest subsoil

    Directory of Open Access Journals (Sweden)

    Bachmann Jörg

    2016-06-01

    Full Text Available Most recent studies on soil water repellency (WR were limited to the humous topsoil or to shallow subsoil layers slightly below the main root zone to approximately 0.5 m depth. Hence, the main objective of the present study was to investigate the wettability pattern of a forest soil including the deeper subsoil. The selected site was a 100 years old beech forest on a well-drained sandy Cambisol in northern Germany which showed moderate to partly extended acidification. Results obtained from three sampling transects (3 m length, 2 m depth; sampling grid 8 × 8 samples per transect; minimum distance of sampling locations to nearest tree about 0.5 m show that contact angles (CA were always in the subcritical WR range (0° < CA < 90°. Significant impact of the tree distance on WR was not observed for any of the transects. A prominent feature of two transects was the minimum WR level (CA < 10° for samples with soil organic carbon (SOC contents around 0.25–0.4%. For the topsoils it was observed that CA increased with SOC content from that minimum to a maximum CA of 60–75° for transects 1 and 2 with mean pH values < 3.5. For transect 3 with slightly higher average pH close to 4.0, average CA of samples were always < 10° and showed no trend to increase with increasing SOC content or other soil parameters like N content or C/N ratio. Subsoil samples, however, behave differently with respect to SOC: for these samples, generally low in SOC, the CA increase with decreasing SOC occurred at all transects for approximately 50% of the samples but did not show any clear tendencies with respect to further parameters like texture, pH or N content. We conclude that the SOC content is the most prominent parameter determining wettability, either positively correlated with WR for topsoils or negatively correlated for subsoil samples very low in SOC. We finally conclude for moderately acid beech forest stands that emerging WR starts in the A horizon after

  14. Comparison of Decomposition Rates of Beech (Fagus orientalis Lipsky) and Spruce (Picea orientalis (L.) Link) Litter in Pure and Mixed Stands of Both Species in Artvin, Turkey

    OpenAIRE

    SARIYILDIZ, Temel; TÜFEKÇİOĞLU, Aydın; Küçük, Mehmet

    2005-01-01

    The decomposition of spruce, beech and mixed litters of spruce and beech was investigated over 3.5 years in beech, spruce and mixed (beech/spruce) stands using less than 1.5 mm mesh litter bags. Initially, carbon, nitrogen, lignin and cellulose concentrations, and C:N and lignin:N ratios were determined in beech and spruce litters. For all sampling intervals, mixed litters showed higher decay rates than individual beech and spruce litters in both pure stands and mixed stands. Spruce decompose...

  15. Non-linear height-diameter models for oriental beech (Fagus orientalis Lipsky in the Hyrcanian forests, Iran

    Directory of Open Access Journals (Sweden)

    Ahmadi, K.

    2013-01-01

    Full Text Available The relationship between tree height and diameter is an important element in growth and yield models, in carbon budget and timber volume models, and in the description of stand dynamics. Six non-linear growth functions (i.e. Chapman-Richards, Schnute, Lundqvist/Korf, Weibull, Modified Logistic and Exponential were fitted to tree height-diameter data of oriental beech in the Hyrcanian mixed hardwood forests of Iran. The predictive performance of these models was in the first place assessed by means of different model evaluation criteria such as adjusted R squared (adjR2, root mean square error (RMSE, Akaike information criterion (AIC, mean difference (MD, mean absolute difference (MAD and mean square (MS error criteria. Although each of the six models accounted for approximately 75% of total variation in height, a large difference in asymptotic estimates was observed. Apart from this, the predictive performance of the models was also evaluated by means of cross-validation and by splitting the data into 5-cm diameter classes. Plotting the MD in relation to these diameter at breast height (DBH classes showed for all growth functions, except for the Modified Logistic function, similar mean prediction errors for small- and medium-sized trees. Large-sized trees, however, showed a higher mean prediction error. The Modified Logistic function showed the worst performance due to a large model bias. The Exponential and Lundqvist/Korf models were discarded due to their showing biologically illogical behavior and unreasonable estimates for the asymptotic coefficient, respectively. Considering all the above-mentioned criteria, the Chapman-Richards, Weibull, and Schnute functions provided the most satisfactory height predictions. However, we would recommend the Chapman-Richards function for further analysis because of its higher predictive performance.

  16. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    Directory of Open Access Journals (Sweden)

    M. Pihlatie

    2005-05-01

    Full Text Available Spring time soil nitrous oxide (N2O fluxes were measured in an old beech (Fagus sylvatica L. forest with eddy covariance (EC and chamber techniques. The aim was to compare the two techniques and to test whether EC can be used in the trunk-space of the forest to measure N2O. Mean N2O fluxes over the five week measurement period were 5, 10 and 16 μg N m-2h-1 from EC, automatic chamber and manual chambers, respectively. When data from one hot spot chamber was excluded the mean N2O flux of 8 μg N m-2h-1 from the soil chambers nearly equaled to the mean flux of 7 μg N m-2h-1 measured with EC from the direction were soil chambers located. Spatial variability in the N2O emissions was high in soil chamber measurements, while the EC integrated over this spatial variability and suggested that N2O emissions were uniform within the footprint area. The highest emissions measured with the EC occurred during the first week of May when the trees were leafing and when soil moisture content was at its highest. To our knowledge, this is the first study to demonstrate that the EC technique can be used to measure N2O fluxes in the trunk-space of a forest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placing of the chambers should be considered carefully to cover the heterogeneity in the soil N2O emissions.

  17. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    Directory of Open Access Journals (Sweden)

    M. Pihlatie

    2005-01-01

    Full Text Available Spring time nitrous oxide (N2O emissions from an old beech (Fagus sylvatica L. forest were measured with eddy covariance (EC and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters. Mean N2O fluxes over the five week measurement period were 5.6±1.1, 10±1 and 16±11 μg N m−2 h−1 from EC, automatic chamber and manual chambers, respectively. High temporal variability characterized the EC fluxes in the trunk-space. To reduce this variability, resulting mostly from random uncertainty due to measuring fluxes close to the detection limit, we averaged the fluxes over one day periods. The variability in the chamber measurements was much smaller and dominated by high small scale spatial variability. The highest emissions measured by the EC method occurred during the first week of May when the trees were leafing and the soil moisture content was at its highest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placement of the chambers should be considered carefully to cover the spatial variability in the soil N2O emissions. The EC technique, applied in this study, is a promising alternative tool to measure ecosystem level N2O fluxes in forest ecosystems. To our knowledge, this is the first study to demonstrate that the EC technique can be used to measure N2O fluxes in the trunk-space of a forest.

  18. Seasonal variation in functional properties of microbial communities in beech forest soil.

    Science.gov (United States)

    Koranda, Marianne; Kaiser, Christina; Fuchslueger, Lucia; Kitzler, Barbara; Sessitsch, Angela; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2013-05-01

    Substrate quality and the availability of nutrients are major factors controlling microbial decomposition processes in soils. Seasonal alteration in resource availability, which is driven by plants via belowground C allocation, nutrient uptake and litter fall, also exerts effects on soil microbial community composition. Here we investigate if seasonal and experimentally induced changes in microbial community composition lead to alterations in functional properties of microbial communities and thus microbial processes. Beech forest soils characterized by three distinct microbial communities (winter and summer community, and summer community from a tree girdling plot, in which belowground carbon allocation was interrupted) were incubated with different (13)C-labeled substrates with or without inorganic N supply and analyzed for substrate use and various microbial processes. Our results clearly demonstrate that the three investigated microbial communities differed in their functional response to addition of various substrates. The winter communities revealed a higher capacity for degradation of complex C substrates (cellulose, plant cell walls) than the summer communities, indicated by enhanced cellulase activities and reduced mineralization of soil organic matter. In contrast, utilization of labile C sources (glucose) was lower in winter than in summer, demonstrating that summer and winter community were adapted to the availability of different substrates. The saprotrophic community established in girdled plots exhibited a significantly higher utilization of complex C substrates than the more plant root associated community in control plots if additional nitrogen was provided. In this study we were able to demonstrate experimentally that variation in resource availability as well as seasonality in temperate forest soils cause a seasonal variation in functional properties of soil microorganisms, which is due to shifts in community structure and physiological

  19. Photosynthetic traits of Siebold's beech and oak saplings grown under free air ozone exposure in northern Japan

    International Nuclear Information System (INIS)

    We set up a free-air ozone (O3) exposure system for determining the photosynthetic responses of Siebold's beech (Fagus crenata) and oak (Quercus mongolica var. crispula) to O3 under field conditions. Ten-year-old saplings of beech and oak were exposed to an elevated O3 concentration (60 nmol mol−1) during daytime from 6 August to 11 November 2011. Ozone significantly reduced the net photosynthetic rate in leaves of both species in October, by 46% for beech and 15% for oak. In beech there were significant decreases in maximum rate of carboxylation, maximum rate of electron transport in photosynthesis, nitrogen content and photosynthetic nitrogen use efficiency, but not in oak. Stomatal limitation of photosynthesis was unaffected by O3. We therefore concluded photosynthesis in beech is more sensitive to O3 than that in oak, and the O3-induced reduction of photosynthetic activity in beech was due not to stomatal closure, but to biochemical limitation. -- Highlights: ► A free air ozone exposure system was set up in northern Japan. ► Beech is more sensitive to ozone than oak. ► Decrease of photosynthesis in beech was mainly due to biochemical limitation. -- Photosynthesis of beech is more sensitive to free air ozone exposure than that of oak

  20. Meteorological Drivers of Extremes in Daily Stem Radius Variations of Beech, Oak, and Pine in Northeastern Germany: An Event Coincidence Analysis.

    Science.gov (United States)

    Siegmund, Jonatan F; Sanders, Tanja G M; Heinrich, Ingo; van der Maaten, Ernst; Simard, Sonia; Helle, Gerhard; Donner, Reik V

    2016-01-01

    Observed recent and expected future increases in frequency and intensity of climatic extremes in central Europe may pose critical challenges for domestic tree species. Continuous dendrometer recordings provide a valuable source of information on tree stem radius variations, offering the possibility to study a tree's response to environmental influences at a high temporal resolution. In this study, we analyze stem radius variations (SRV) of three domestic tree species (beech, oak, and pine) from 2012 to 2014. We use the novel statistical approach of event coincidence analysis (ECA) to investigate the simultaneous occurrence of extreme daily weather conditions and extreme SRVs, where extremes are defined with respect to the common values at a given phase of the annual growth period. Besides defining extreme events based on individual meteorological variables, we additionally introduce conditional and joint ECA as new multivariate extensions of the original methodology and apply them for testing 105 different combinations of variables regarding their impact on SRV extremes. Our results reveal a strong susceptibility of all three species to the extremes of several meteorological variables. Yet, the inter-species differences regarding their response to the meteorological extremes are comparatively low. The obtained results provide a thorough extension of previous correlation-based studies by emphasizing on the timings of climatic extremes only. We suggest that the employed methodological approach should be further promoted in forest research regarding the investigation of tree responses to changing environmental conditions. PMID:27375625

  1. Meteorological Drivers of Extremes in Daily Stem Radius Variations of Beech, Oak and Pine in Northeastern Germany: An Event Coincidence Analysis

    Directory of Open Access Journals (Sweden)

    Jonatan Frederik Siegmund

    2016-06-01

    Full Text Available Observed recent and expected future increases in frequency and intensity of climatic extremes in central Europe may pose critical challenges for domestic tree species. Continuous dendrometer recordings provide a valuable source of information on tree stem diameter or radius variations, offering the possibility to study a tree's response to environmental influences at a high temporal resolution. In this study, we analyze stem radius variations (SRV of three domestic tree species (beech, oak and pine from 2012 to 2014. We use the novel statistical approach of event coincidence analysis (ECA to investigate the simultaneous occurrence of extreme daily weather conditions and extreme SRVs, where extremes are defined with respect to the common values at a given phase of the annual growth period. Besides defining extreme events based on individual meteorological variables, we additionally introduce conditional and joint ECA as new multivariate extensions of the original methodology and apply them for testing 105 different combinations of variables regarding their impact on SRV extremes. Our results reveal a strong susceptibility of all three species to the extremes of several meteorological variables. Yet, the inter-species differences regarding their response to the meteorological extremes are comparatively low. The obtained results provide a thorough extension of previous correlation-based studies by emphasizing on the timings of climatic extremes only. We suggest that the employed methodological approach should be further promoted in forest research regarding the investigation of tree responses to changing environmental conditions.

  2. Substrate influences ecophysiological performance of tree seedlings.

    Science.gov (United States)

    Pröll, Gisela; Hietz, Peter; Delaney, Christina M; Katzensteiner, Klaus

    2016-01-01

    Unfavourable soil conditions frequently limit tree regeneration in mountain forests on calcareous bedrock. Rocky, shallow organic soils on dolomite pose a particular problem for tree regeneration due to commonly restricted water and nutrient supplies. Moreover, an often dense layer of understorey vegetation competes for the limited resources available. Hence, an array of interacting factors impairs tree seedlings' performance on dolomite, but there is little information on the ecophysiological mechanisms. We studied the effects of substrate, competing vegetation and foliar nutrient concentrations on the photosynthetic rate (A), stomatal conductance (gs) and leaf water potentials (ψ) of sycamore (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), spruce [Picea abies (L.) Karst.] and larch (Larix decidua Mill.) under controlled (well-watered/drought-stressed) conditions and under prevailing field conditions. While A and gs of well-watered spruce in the pot experiment were reduced by the mineral substrate, the organic dolomite substrate with dense competing vegetation reduced gs and ψ of sycamore, spruce and larch under drought-stressed conditions in the field. For sycamore and spruce, A and gs were strongly correlated with foliar nitrogen (N) and potassium (K) concentrations in the pot experiment. In contrast, soil water primarily affected beech and larch. Finally, dense competing vegetation negatively affected A and gs of spruce and A of larch on dolomite. Our results highlight the critical role of N, K and water availability for tree seedlings in shallow soils on calcareous bedrock. On these sites, natural tree regeneration is at particular risk from episodic drought, a likely consequence of climate change.

  3. Substrate influences ecophysiological performance of tree seedlings.

    Science.gov (United States)

    Pröll, Gisela; Hietz, Peter; Delaney, Christina M; Katzensteiner, Klaus

    2016-01-01

    Unfavourable soil conditions frequently limit tree regeneration in mountain forests on calcareous bedrock. Rocky, shallow organic soils on dolomite pose a particular problem for tree regeneration due to commonly restricted water and nutrient supplies. Moreover, an often dense layer of understorey vegetation competes for the limited resources available. Hence, an array of interacting factors impairs tree seedlings' performance on dolomite, but there is little information on the ecophysiological mechanisms. We studied the effects of substrate, competing vegetation and foliar nutrient concentrations on the photosynthetic rate (A), stomatal conductance (gs) and leaf water potentials (ψ) of sycamore (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), spruce [Picea abies (L.) Karst.] and larch (Larix decidua Mill.) under controlled (well-watered/drought-stressed) conditions and under prevailing field conditions. While A and gs of well-watered spruce in the pot experiment were reduced by the mineral substrate, the organic dolomite substrate with dense competing vegetation reduced gs and ψ of sycamore, spruce and larch under drought-stressed conditions in the field. For sycamore and spruce, A and gs were strongly correlated with foliar nitrogen (N) and potassium (K) concentrations in the pot experiment. In contrast, soil water primarily affected beech and larch. Finally, dense competing vegetation negatively affected A and gs of spruce and A of larch on dolomite. Our results highlight the critical role of N, K and water availability for tree seedlings in shallow soils on calcareous bedrock. On these sites, natural tree regeneration is at particular risk from episodic drought, a likely consequence of climate change. PMID:26446268

  4. Effect of tree species substitution on organic matter biodegradability and mineral nutrient availability in a temperate topsoil

    OpenAIRE

    Moukoumi, Judicaël; Munier-Lamy, Colette; Berthelin, Jacques; Ranger, Jacques

    2006-01-01

    In the Breuil-Chenue experimental site (Morvan, France), the native forest, a 150-year-old coppice with standards dominated by beech was partly clear-cut thirty years ago and replanted with several tree species. Soil samples were collected from the A1 horizon, in the 0–5 cm layer of the preserved native forest and three plantations: European beech, Douglas-fir and Norway spruce. Aliquots of 0–2 mm sieved soils were incubated for 40 days under laboratory conditions (15 ◦C, water-holding capaci...

  5. Assessment of spatial discordance of primary and effective seed dispersal of European beech (Fagus sylvatica L.) by ecological and genetic methods.

    Science.gov (United States)

    Millerón, M; López de Heredia, U; Lorenzo, Z; Alonso, J; Dounavi, A; Gil, L; Nanos, N

    2013-03-01

    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 direct kernel fitting of mother-to-offspring distances estimated by a parentage analysis or were spatially explicit models based on the genotype frequencies of offspring (competing sources model and Moran-Clark's Model). A fully integrated mixed model was based on inverse modelling, but used the number of genotypes as input data (gene shadow model). The potential sources of error and limitations of each seed dispersal estimation method are discussed. The mean dispersal distances for seeds and saplings estimated with these five methods were higher than those obtained by previous estimations for European beech forests. All the methods show strong discordance between primary and effective dispersal kernel parameters, and for dispersal directionality. While seed rain was released mostly under the canopy, saplings were established far from mother trees. This discordant pattern may be the result of the action of secondary dispersal by animals or density-dependent effects; that is, the Janzen-Connell effect. PMID:23379310

  6. Up in the tree--the overlooked richness of bryophytes and lichens in tree crowns.

    Directory of Open Access Journals (Sweden)

    Steffen Boch

    Full Text Available Assessing diversity is among the major tasks in ecology and conservation science. In ecological and conservation studies, epiphytic cryptogams are usually sampled up to accessible heights in forests. Thus, their diversity, especially of canopy specialists, likely is underestimated. If the proportion of those species differs among forest types, plot-based diversity assessments are biased and may result in misleading conservation recommendations. We sampled bryophytes and lichens in 30 forest plots of 20 m × 20 m in three German regions, considering all substrates, and including epiphytic litter fall. First, the sampling of epiphytic species was restricted to the lower 2 m of trees and shrubs. Then, on one representative tree per plot, we additionally recorded epiphytic species in the crown, using tree climbing techniques. Per tree, on average 54% of lichen and 20% of bryophyte species were overlooked if the crown was not been included. After sampling all substrates per plot, including the bark of all shrubs and trees, still 38% of the lichen and 4% of the bryophyte species were overlooked if the tree crown of the sampled tree was not included. The number of overlooked lichen species varied strongly among regions. Furthermore, the number of overlooked bryophyte and lichen species per plot was higher in European beech than in coniferous stands and increased with increasing diameter at breast height of the sampled tree. Thus, our results indicate a bias of comparative studies which might have led to misleading conservation recommendations of plot-based diversity assessments.

  7. Behavior of Beech Sawdust during Densification into a Solid Biofuel

    Directory of Open Access Journals (Sweden)

    Peter Križan

    2015-06-01

    Full Text Available In solid biofuel manufacture technological and material variables influence the densification process and thus also the final briquette quality. The impact of these technological variables, especially compression pressure and compression temperature, and also of the material parameters (particle size and moisture content can generally be observed during biomass densification in the quality indicators, where the abovementioned variables have a significant influence, especially on the mechanical indicators of quality (briquette density, mechanical durability, etc.. This paper presents the results of experimental research dealing with determining the relationship between the technological and the material variables during densification of beech sawdust. The main goal of the paper is to determine the mutual interaction between compression pressure, compression temperature and material particle size. Research findings were obtained using single-axis densification. The influence of the particle size interacting with compression pressure and compression temperature on the final briquette density was determined. The research findings obtained should prove valuable in briquette production and also in the engineering of densification machines.

  8. Planting Trees

    OpenAIRE

    Relf, Diane

    2009-01-01

    The key aspects in planning a tree planting are determining the function of the tree, the site conditions, that the tree is suited to site conditions and space, and if you are better served by a container-grown. After the tree is planted according to the prescribed steps, you must irrigate as needed and mulch the root zone area.

  9. Ungulate Impact on Natural Regeneration in Spruce-Beech-Fir Stands in Černý důl Nature Reserve in the Orlické Hory Mountains, Case Study from Central Sudetes

    Directory of Open Access Journals (Sweden)

    Zdeněk Vacek

    2014-11-01

    Full Text Available The paper presents the results of a study on tree regeneration of forest stands in the Černý důl Nature Reserve, which is situated in the Orlické hory Mountains Protected Landscape area in the Czech Republic. Research was conducted in a spruce-beech stand with an admixture of silver fir, sycamore maple and rowan on two comparative permanent research plots (PRPs (PRP 1—fenced enclosure and PRP 2—unfenced. Typological, soil, phytosociological and stand characteristics of the two PRPs are similar. The results showed that ungulate browsing is a limiting factor for successful development of natural regeneration of autochthonous tree species. The population of tree species of natural regeneration on the fenced plot (PRP 1 is sufficient in relation to the site and stand conditions. However, natural regeneration on PRP 2 is considerably limited by browsing. Damage is greatest to fir, sycamore maple and rowan; less severe to beech; and the least to spruce.

  10. Characterizing Stand Structure and Growth of Natural Beech Forests for the Development of Sustainable Forest Practices

    DEFF Research Database (Denmark)

    Ghalandarayeshi, Shaaban

    Understanding of ecological processes and the ability to make reasonable forecasts is pivotal for the development of sustainable forest management practices as the effect of specific treatments may not be visible in the lifetime of the forester. Current forest management practices for oriental beech...... management practices in these forests. Like in Iran, sustainable forest management practices are on the agenda in Denmark. Current understanding of near natural forest management relies to a large extend on a series of studies in Suserup Forest – a natural, nemoral European beech forest in Denmark. However...... forests in northern Iran lack such scientific foundation. The objective of the present study is to assist in this process by characterizing growth and stand structure of oriental beech for a range of growing conditions in northern Iran and to provide useful insight for application in sustainable...

  11. Aluminum solubility and mobility in relation to organic carbon in surface soils affected by six tree species of the northeastern United States

    NARCIS (Netherlands)

    Dijkstra, F.A.; Fitzhugh, R.D.

    2003-01-01

    We compared Al solubility and mobility in surface soils among six tree species (sugar maple [Acer saccharum], white ash [Fraxinus americana], red maple [Acer rubrum, L.], American beech [Fagus grandifolia, Ehrh.], red oak [Quercus rubra, L.], and hemlock [Tsuga canadensis, Carr.]) in a mixed hardwoo

  12. Differences in soil fungal communities between European beech (Fagus sylvatica L. dominated forests are related to soil and understory vegetation.

    Directory of Open Access Journals (Sweden)

    Tesfaye Wubet

    Full Text Available 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 in three German regions, the Schwäbische Alb in Southwestern, the Hainich-Dün in Central and the Schorfheide Chorin in the Northeastern Germany, using internal transcribed spacer (ITS rDNA pyrotag sequencing. Multiple sequence quality filtering followed by sequence data normalization revealed 1655 fungal operational taxonomic units. Further analysis based on 722 abundant fungal OTUs revealed the phylum Basidiomycota to be dominant (54% and its community to comprise 71.4% of ectomycorrhizal taxa. Fungal community structure differed significantly (p≤0.001 among the three regions and was characterized by non-random fungal OTUs co-occurrence. Soil parameters, herbaceous understory vegetation, and litter cover affected fungal community structure. However, within each study region we found no difference in fungal community structure between management types. Our results also showed region specific significant correlation patterns between the dominant ectomycorrhizal fungal genera. This suggests that soil fungal communities are region-specific but nevertheless composed of functionally diverse and complementary taxa.

  13. Autoencoder Trees

    OpenAIRE

    İrsoy, Ozan; Alpaydın, Ethem

    2014-01-01

    We discuss an autoencoder model in which the encoding and decoding functions are implemented by decision trees. We use the soft decision tree where internal nodes realize soft multivariate splits given by a gating function and the overall output is the average of all leaves weighted by the gating values on their path. The encoder tree takes the input and generates a lower dimensional representation in the leaves and the decoder tree takes this and reconstructs the original input. Exploiting t...

  14. Microwave sensing of tree trunks

    Science.gov (United States)

    Jezova, Jana; Mertens, Laurence; Lambot, Sebastien

    2015-04-01

    was divided into three sections to separate parts with different moisture (heartwood and sapwood) or empty space (decays). For easier manipulation with the antenna we developed a special ruler for measuring the distance along the scans. Instead of the surveying wheel we read the distance with a camera, which was fixed on the antenna and focused on the ruler with a binary pattern. Hence, during whole measurement and the data processing we were able to identify an accurate position on the tree in view of the scan. Some preliminary measurements on the trees were also conducted. They were performed using a GSSI 900 MHz antenna. Several tree species (beech, horse-chestnut, birch, ...) in Louvain-la-Neuve and Brussels, Belgium, have been investigated to see the internal structure of the tree decays. The measurements were carried out mainly by circumferential measurement around the trunk and also by vertical measurement along the trunk for approximate detection of the cavity. The comparison between the numerical simulations, simplified tree trunk model and real data from trees is presented. This research is funded by the Fonds de la Recherche Scientifique (FNRS, Belgium) and benefits from networking activities carried out within the EU COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

  15. Summer drought impedes beech seedling performance more in a sub-Mediterranean forest understory than in small gaps.

    Science.gov (United States)

    Robson, T Matthew; Rodríguez-Calcerrada, Jesús; Sánchez-Gómez, David; Aranda, Ismael

    2009-02-01

    Refugia of mixed beech forest persist in the central mountains of the Iberian Peninsula at the south-western limit of European beech (Fagus sylvatica L.) distribution. The lack of beech regeneration is a concern in this region that has experienced reduced rainfall and higher temperatures over the past 30 years. Beech is considered especially susceptible to climate change because of its conservative shade-tolerant growth strategy; hence seedling responses to drought stress in gaps and in the understory are of particular interest. During the summer of 2007, a watering treatment raised the soil water content by up to 5% in gap and understory plots of beech seedlings in a mixed beech forest. Root-collar diameter was increased by our watering treatment in understory seedlings. Neither drought-avoidance through stomatal closure nor physiological drought-tolerance mechanisms were able to mitigate the effects of water stress in the understory seedlings, whereas osmotic adjustment enhanced the ability of the gap seedlings to tolerate water stress. Overall, high photosynthetic rates in the gaps, despite the photoinhibitory effects of high radiation, allowed gap seedlings to survive and grow better than the understory seedlings irrespective of water availability. Our results indicate that further intensification of summer drought, predicted for the Iberian Peninsula, will hinder the establishment of a beech seedling bank in the understory because of the conflicting seedling trait responses to simultaneously withstand water stress and to tolerate shade. PMID:19203950

  16. Shading and root-shoot relations in saplings of silver birch, pedunculate oak and beech

    NARCIS (Netherlands)

    Hees, van A.F.M.; Clerkx, A.P.P.M.

    2003-01-01

    Silver birch (Betula pendula Roth), pedunculate oak (Quercus robur L.) and beech (Fagus sylvatica L.) can regenerate successfully under a canopy of Scots pine (Pinus sylvestris L.). Shading reduces plant growth and modifies plant form, two related aspects. This study focuses on the effects of shadin

  17. Methanol and other VOC fluxes from a Danish beech forest during late springtime

    DEFF Research Database (Denmark)

    Schade, Gunnar W.; Solomon, Sheena J.; Dellwik, Ebba;

    2011-01-01

    In-canopy mixing ratio gradients and above-canopy fluxes of several volatile organic compounds (VOCs) were measured using a commercial proton transfer reaction mass spectrometer (PTR-MS) in a European beech (Fagus sylvatica) forest in Denmark. Fluxes of methanol were bidirectional: Emission...

  18. Signals from beech (Fagus sylvatica L.) in response to precipitation extremes - flowering induction and reduced foliation

    DEFF Research Database (Denmark)

    Callesen, Ingeborg

    Reduced foliation in older (but also young) beech (Fagus sylvatica L.) stands was observed in Denmark in the mid 1990ies and culminated with the 1996 summer drought and heat wave. Large differences in the degree of reduced foliation between regions and within stands were observed e.g. reflecting ......) caused by poor internal drainage and minor depressions in micro relief ....

  19. Effect of particle geometry and micro-structure on fast pyrolysis of beech wood

    NARCIS (Netherlands)

    Westerhof, R.J.M.; Nygard, H.; Swaaij, van W.P.M.; Kersten, S.R.A.; Brilman, D.W.F.

    2012-01-01

    The influence of particle geometry and microstructure in fast pyrolysis of beech wood has been investigated. Milled wood particles (<0.08–2.4 mm) and natural wood cylinders (2–14 mm) with different lengths (10–50 mm) and artificial wood cylinders (Dp = 0.5–14 mm) made of steel walls, filled with sma

  20. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    DEFF Research Database (Denmark)

    Pihlatie, M.; Rinne, J.; Ambus, P.;

    2005-01-01

    Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameter...

  1. ESTIMATING ROOT RESPIRATION IN SPRUCE AND BEECH: DECREASES IN SOIL RESPIRATION FOLLOWING GIRDLING

    Science.gov (United States)

    A study was undertaken to follow seasonal fluxes of CO2 from soil and to estimate the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) in a mixed stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) near Freising, Germany. Matu...

  2. Wood structural differences between northern and southern beech provenances growing at a moderate site

    NARCIS (Netherlands)

    Eilmann, B.; Sterck, F.J.; Wegner, L.; Vries, de S.M.G.; Arx, von G.; Mohren, G.M.J.; Ouden, den J.; Sass-Klaassen, U.G.W.

    2014-01-01

    Planting provenances originating from southern to northern locations has been discussed as a strategy to speed up species migration and mitigate negative effects of climate change on forest stability and productivity. Especially for drought-susceptible species such as European beech (Fagus sylvatica

  3. Gap formation in Danish beech (Fagus sylvatica) forests of low management intensity

    DEFF Research Database (Denmark)

    Ritter, Eva; Vesterdal, Lars

    2006-01-01

    Soil moisture content (0-90 cm depth) and nitrate-nitrogen (NO3-N) concentrations in soil solution (90 cm depth) were monitored after gap formation (diameter 15-18 m) in three Danish beech-dominated forests on nutrient-rich till soils. NO3-N drainage losses were estimated by the water balance mod...

  4. Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

    DEFF Research Database (Denmark)

    Pihlatie, M.; Rinne, J.; Ambus, P.;

    2005-01-01

    Spring time nitrous oxide (N2O) emissions from an old beech (Fagus sylvatica L.) forest were measured with eddy covariance (EC) and chamber techniques. The aim was to obtain information on the spatial and temporal variability in N2O emissions and link the emissions to soil environmental parameters...

  5. Impact of tree species on soil carbon stocks and soil acidity in southern Sweden

    International Nuclear Information System (INIS)

    The impact of tree species on soil carbon stocks and acidity in southern Sweden was studied in a non-replicated plantation with monocultures of 67-year-old ash (Fraxinus excelsior L.), beech (Fagus silvatica L.), elm (Ulmus glabra Huds.), hornbeam (Carpinusbetulus L.), Norway spruce (Picea abies L.) and oak (Quercus robur L.). The site was characterized by a cambisol on glacial till. Volume-determined soil samples were taken from the O-horizon and mineral soil layers to 20 cm. Soil organic carbon (SOC), total nitrogen (TN), pH (H2O), cation-exchange capacity and base saturation at pH 7 and exchangeable calcium, magnesium, potassium and sodium ions were analysed in the soil fraction hornbeam > oak > beech > ash > elm. The pH in the O-horizon ranged in the order elm > ash > hornbeam > beech > oak > spruce. In the mineral soil, SOC and TN ranged in the order elm > oak > ash = hornbeam > spruce > beech, i.e. partly reversed, and pH ranged in the same order as for the O-horizon. It is suggested that spruce is the best option for fertile sites in southern Sweden if the aim is a high carbon sequestration rate, whereas elm, ash and hornbeam are the best solutions if the aim is a low soil acidification rate

  6. Impact of Elevated PCO2 on Mass Flow of Reduced Nitrogen in Trees

    Institute of Scientific and Technical Information of China (English)

    Xi-Ping Liu

    2006-01-01

    To analyze the effects of elevated carbon dioxide concentration (PCO2) on the mass flow of reduced nitrogen (N) in the phloem and xylem of trees, juvenile beech (Fagus sylvatica L.) and spruce (Picea abies (L.)Karst.) were grown in phytotrons and exposed to ambient and elevated PCO2 (plus 687.5 mg/m3 CO2) for three growing seasons. Elevated PCO2 significantly decreased the mass flow of N from the shoot to roots of beech by significantly reducing the concentration of soluble amino compounds in the phloem, even if the area of conductive phloem of cross-sectional bark tissue was significantly increased, because of less callus deposition in the sieve elements. In spruce, the downward mass flow of reduced N also tended to be decreased, similar to that in beech. Resembling findings in the phloem, N mass flow from roots to shoot in both tree species was significantly diminished owing to significantly reduced concentrations of amino compounds in the xylem and a lower transpiration rate. Therefore, the mass flow of reduced N between shoots and roots of trees was mainly governed by the concentrations of soluble amino compounds in the phloem and xylem in relation to the loading of reduced N in both long-distance transport pathways.

  7. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.;

    2013-01-01

    We introduce a new compression scheme for labeled trees based on top trees [3]. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  8. Tree compression with top trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Landau, Gad M.;

    2015-01-01

    We introduce a new compression scheme for labeled trees based on top trees. Our compression scheme is the first to simultaneously take advantage of internal repeats in the tree (as opposed to the classical DAG compression that only exploits rooted subtree repeats) while also supporting fast...

  9. Plants control the seasonal dynamics of microbial N cycling in a beech forest soil by belowground C allocation.

    Science.gov (United States)

    Kaiser, Christina; Fuchslueger, Lucia; Koranda, Marianne; Gorfer, Markus; Stange, Claus F; Kitzler, Barbara; Rasche, Frank; Strauss, Joseph; Sessitsch, Angela; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2011-05-01

    Soil microbes in temperate forest ecosystems are able to cycle several hundreds of kilograms of N per hectare per year and are therefore of paramount importance for N retention. Belowground C allocation by trees is an important driver of seasonal microbial dynamics and may thus directly affect N transformation processes over the course of the year. Our study aimed at unraveling plant controls on soil N cycling in a temperate beech forest at a high temporal resolution over a time period of two years, by investigating the effects of tree girdling on microbial N turnover. In both years of the experiment, we discovered (1) a summer N mineralization phase (between July and August) and (2) a winter N immobilization phase (November-February). The summer mineralization phase was characterized by a high N mineralization activity, low microbial N uptake, and a subsequent high N availability in the soil. During the autumn/winter N immobilization phase, gross N mineralization rates were low, and microbial N uptake exceeded microbial N mineralization, which led to high levels of N in the microbial biomass and low N availability in the soil. The observed immobilization phase during the winter may play a crucial role for ecosystem functioning, since it could protect dissolved N that is produced by autumn litter degradation from being lost from the ecosystem during the phase when plants are mostly inactive. The difference between microbial biomass N levels in winter and spring equals 38 kg N/ha and may thus account for almost one-third of the annual plant N demand. Tree girdling strongly affected annual N cycling: the winter N immobilization phase disappeared in girdled plots (microbial N uptake and microbial biomass N were significantly reduced, while the amount of available N in the soil solution was enhanced). This was correlated to a reduced fungal abundance in autumn in girdled plots. By releasing recently fixed photosynthates to the soil, plants may thus actively control the

  10. Frost Crack Impact on European Beech (Fagus sylvatica L. Wood Quality

    Directory of Open Access Journals (Sweden)

    Vasile R. CÂMPU

    2015-04-01

    Full Text Available Frost crack represents one of the main defects which affect European beech wood quality. Therefore, the purpose of this paper is to improve the knowledge regarding both the impact of frost crack on European beech wood quality and the frost crack characteristics which affect wood quality. In order to do this, nineteen European beech trunks with frost crack have been studied. Each trunk has been cross-cut every 1 meter and the characteristics of frost crack and frost crack star-shaped heart have been measured in each cross-cut section. The defects which accompany frost crack have also been identified in each cross-cut section. Moreover, the possibility of determining these defects using the IML RESIF500 – S Resistograph has been tested. The research has emphasized the existence of statistical correlations between frost crack star-shaped heart expansion, frost crack rib prominence and frost crack length. These correlations are expressed by multiple linear regressions. The presence of defects which affect wood structure leading to a decrease in penetration resistance can be determined accurately with the resistograph. Decay (in frost cracks older than 8 years and ring shake have been identified as the most frequent defects which accompany frost crack. The measurements made on the frost cracks studied have been gathered in a graph which shows frost crack impact on European beech wood quality. The results obtained lead to the improvement of the criteria of European beech wood quality assessment by expanding the already existent knowledge and by identifying new aspects which may complete standing wood quality determination and sorting methods.

  11. A Study of the Ultrastructure and Chemistry of Beech (Fagus grandifolia Ehrh.) Normal Wood Rays and Tension Wood Rays

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tension wood and normal wood rays of American Beech Fagus grandifolia Ehrh. were examined by microscopy and chemical means and no significant differences were...

  12. Evidence of PCDD/Fs and PCBs contamination in trees grown in forests far from their production and contamination-free areas

    OpenAIRE

    Yasuhara, A.; Katami, T; Shibamoto, T

    2014-01-01

    Polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in trees grown in pathless forests were analyzed to investigate their dispersal patterns in the atmosphere. The pg/g levels of 23 PCCD, 22 PCDF, and 54 PCB congeners were identified. The total amount of PCDDs in the red pine tree sample (95.8 pg/g) was approximately 7 times that in the beech tree sample (13.2 pg/g). The total amount of PCDFs in the red pine tree sample (71.1 pg/g) wa...

  13. Impact of interspecific competition and drought on the allocation of new assimilates in trees.

    Science.gov (United States)

    Hommel, R; Siegwolf, R; Zavadlav, S; Arend, M; Schaub, M; Galiano, L; Haeni, M; Kayler, Z E; Gessler, A

    2016-09-01

    In trees, the interplay between reduced carbon assimilation and the inability to transport carbohydrates to the sites of demand under drought might be one of the mechanisms leading to carbon starvation. However, we largely lack knowledge on how drought effects on new assimilate allocation differ between species with different drought sensitivities and how these effects are modified by interspecific competition. We assessed the fate of (13) C labelled assimilates in above- and belowground plant organs and in root/rhizosphere respired CO2 in saplings of drought-tolerant Norway maple (Acer platanoides) and drought-sensitive European beech (Fagus sylvatica) exposed to moderate drought, either in mono- or mixed culture. While drought reduced stomatal conductance and photosynthesis rates in both species, both maintained assimilate transport belowground. Beech even allocated more new assimilate to the roots under moderate drought compared to non-limited water supply conditions, and this pattern was even more pronounced under interspecific competition. Even though maple was a superior competitor compared to beech under non-limited soil water conditions, as indicated by the changes in above- and belowground biomass of both species in the interspecific competition treatments, we can state that beech was still able to efficiently allocate new assimilate belowground under combined drought and interspecific competition. This might be seen as a strategy to maintain root osmotic potential and to prioritise root functioning. Our results thus show that beech tolerates moderate drought stress plus competition without losing its ability to supply belowground tissues. It remains to be explored in future work if this strategy is also valid during long-term drought exposure. PMID:27061772

  14. The effect of drought on forest tree species' nourishment: the chosen path of phosphorus cycling

    OpenAIRE

    Marfo, Theodore Danso

    2015-01-01

    This research sought to evaluate the effect of drought on forest tree species with emphasis on bio-available phosphorus obtained via phosphorus cycling. Soil samples were collected at root zone depth from areas of varied altitudes and tree species thus H-horizon soils from the mountain Spruce forest at Bily Kriz, A-horizon soils from both the young Spruce monoculture at Rajec and Beech forest at Stitna. Acid phosphatase activity of the various soil samples was measured in optimal conditions o...

  15. The potential of beech seedlings to adapt to low P availability in soil - plant versus microbial effects on P mobilising potential in the rhizosphere

    Science.gov (United States)

    Meller, Sonia; Frey, Beat; Frossard, Emmanuel; Spohn, Marie; Schack-Kirchner, Helmer; Luster, Jörg

    2016-04-01

    The objective of our work was to investigate to what extent tree seedlings (Fagus sylvatica) are able to adapt the process of P mobilisation in the rhizosphere according to P speciation in the soil. Such mobilisation activity can include root exudation of P mobilising compounds or stimulation of specific P mobilising soil microbes. We hypothesized that Fagus sylvatica seedlings can adapt their own activity based on their P nutritional status and genetic memory of how to react under a given nutritional situation. To test the hypothesis, we set up a cross-growth experiment with beech of different provenances growing in soil from their own provenance site and in soil differing in P availability. Experiments were performed as a greenhouse experiment, with temperature control and natural light, during one vegetation period in rhizoboxes . We used two acidic forest soils, contrasting in P availability, collected at field sites of the German research priority program "Ecosystem Nutrition". Juvenile trees were collected along with the soils at the sites and planted respectively. The occurrence of P mobilising compounds and available P in the rhizosphere and in bulk soil were measured during the active growth season of the plants. In particular, we assessed phosphatase activity, (measured with zymography and plate enzymatic assay at pH 4,6.5, and 11) carboxylates and phosphate (measured by application of ion exchange membranes to specific soil micro zones, and by microdialysis), and pH (mapping with optodes). Plant P nutrition status was assessed by total P, N/P, phosphatase activity, and metabolic (TCA extractable) P in the leaves. The P-nutritional status of the beech provenances differed markedly independent from the P status of the soil where they were actually grown during experiment. In particular, the juvenile trees from the site rich in mineral P were sufficient in P, while those from the P-poor site with mostly organic P, were deficient. Enzymatic activity at the

  16. Exemplifying whole-plant ozone uptake in adult forest trees of contrasting species and site conditions

    International Nuclear Information System (INIS)

    Whole-tree O3 uptake was exemplified for Picea abies, Fagus sylvatica and Larix decidua in stands at high and low altitude and contrasting water availability through sap flow measurement in tree trunks, intrinsically accounting for drought and boundary layer effects on O3 flux. O3 uptake of evergreen spruce per unit foliage area was enhanced by 100% at high relative to low elevation, whereas deciduous beech and larch showed similar uptake regardless of altitude. The responsiveness of the canopy conductance to water vapor and, as a consequence, O3 uptake to soil moisture and air humidity did not differ between species. Unifying findings at the whole-tree level will promote cause-effect based O3 risk assessment and modeling. - Sap flow-based assessment of whole-tree O3 uptake reflects similar responsiveness of canopy conductance and O3 uptake across contrasting tree species and site conditions

  17. Talking Trees

    Science.gov (United States)

    Tolman, Marvin

    2005-01-01

    Students love outdoor activities and will love them even more when they build confidence in their tree identification and measurement skills. Through these activities, students will learn to identify the major characteristics of trees and discover how the pace--a nonstandard measuring unit--can be used to estimate not only distances but also the…

  18. CULTIVATION OF P. FLORIDA SUPLEMENTED OF RICE BRAIN ON BEECH WOOD WASTE

    Directory of Open Access Journals (Sweden)

    Hüseyin SİVRİKAYA

    1998-03-01

    Full Text Available Cultivation of Pleurotus spp. reached to the second largest in amount after Agaricus bisporus (Lange sing. in the world. There recently has also been growing interest to cultivate them on wastes of forest and agricultural plants in Turkey. In the scope of study Pleurotus florida was produced on beech wood sawmill waste and rice brain. Beech wood sawmill waste (Fagus orientalis Lipsky were used as main substrate and supplemented with rice brain as co-substrate by 10 % W/W, 0 % W/W, 40 % W/W mixing ratios based on dry weights. To produce P. florida substrates were ground, air dried, moistured up to 70-80 % by tap water, supplemented, pasteurized with live steam and spawned. Highest yields (440 gr/kg of P. florida were obtained by supplementing wood waste and rice brain (% 80 + % 20. Furthermore, the best mycelia development were obtained by % 90 + % 10.

  19. The Analysis of Favourable Mass Multiplication Conditions of Defoliator Lymantria Dispar in Beech Forests from Romania

    Directory of Open Access Journals (Sweden)

    TOMESCU Romica

    2010-08-01

    Full Text Available In Romania, Lymantria dispar is a defoliator with a high injury potential that produces strong and frequentgradations in Querqus forests in mixture with beech. The research concerning Lymantria dispar infestation was carriedout by in brushes from Herculane Baths County, with gradations of the defoliator in numerical growth and eruptionphases. The statistical data were processed by using the Discriminative Analysis. It has put into evidence the influenceof stationed and brushes properties on the appearance and development of gradations. Strong infestations dominatebrushes with a reduced consistency (0.4 – 0.7 and included in larger age classes. In eruption phase, one evidences theextension tendency on the altitude of infestations (advancing towards the versant, strongly inclined and in brushes witha larger participation of beech, situated in different age classes and middle-superior production classes, with a morevigorous vegetation stage.

  20. Plant biodiversity of beech forests in central-northern Italy: a methodological approach for conservation purposes

    OpenAIRE

    Marcantonio M; Chiarucci A; Maccherini S; Guglietta D; Bacaro G

    2012-01-01

    Forests are reckoned essentials as biodiversity reservoirs and carbon sinks. Current threats to forest ecosystems (e.g., climate changes, habitat loss and fragmentation, management changes) call for monitoring their biodiversity and preserving their ecological functions. In this study, we characterized plants diversity of five beech forests located in central and north Apennines mountain chain, using results by a probabilistic sampling. In order to achieve our goals, we have considered specie...

  1. Relaxed molecular clock provides evidence for long-distance dispersal of Nothofagus (southern beech).

    OpenAIRE

    Michael Knapp; Karen Stöckler; David Havell; Frédéric Delsuc; Federico Sebastiani; Lockhart, Peter J.

    2005-01-01

    Nothofagus (southern beech), with an 80-million-year-old fossil record, has become iconic as a plant genus whose ancient Gondwanan relationships reach back into the Cretaceous era. Closely associated with Wegener's theory of “Kontinentaldrift”, Nothofagus has been regarded as the “key genus in plant biogeography”. This paradigm has the New Zealand species as passengers on a Moa's Ark that rafted away from other landmasses following the breakup of Gondwana. An alternative explanation for the c...

  2. Methanol and other VOC fluxes from a Danish beech forest during springtime

    OpenAIRE

    Schade, G. W.; Solomon, S. J.; E. Dellwik; K. Pilegaard; A. Ladstätter-Weissenmayer

    2008-01-01

    In-canopy mixing ratio gradients and above-canopy fluxes of several volatile organic compounds (VOCs) were measured using a commercial proton transfer reaction mass spectrometer (PTR-MS) in a European beech (Fagus sylvatica) forest in Denmark. Emission fluxes of methanol occurred dominantly late at night, which was supported by highest mixing ratios in the crown region, and is in line with recent controlled laboratory experiments. Also confirming previous measurements, mono...

  3. Chemical Elements in Mulch and Litterfall of Beech Ecosystems and Their Total Turnover

    OpenAIRE

    Mariyana I. Lyubenovа; Violeta G. Dimitrova

    2011-01-01

    The beech communities on the territory of Bulgaria had been objects of regional, local as well as large scale national investigations aiming their classification, determination of their ecological characteristics, conservation status, habitats etc. They are included as objects of the intensive monitoring of forest ecosystems in Bulgaria also. The investigations of chemical content of the litter – fall in these forests were conducted until now. The novelty of the present research is investiga...

  4. Types of ectomycorrhizae on beech seedlings (Fagus sylvatica L.) in rhizotrons

    OpenAIRE

    Štraus, Ines; Bajc, Marko; Grebenc, Tine; Mali, Boštjan; Kraigher, Hojka

    2011-01-01

    Natural processes or human activities affect environmental conditions, as reflected in the structure of the communities and the level of ectomycorrhizalfungi. The aim of the study was to determine the potential impacts of several temperature regimes of air and soil (substrate) on the occurrence and species diversity of ectomycorrhizal fungi in symbiosis and in the substrate. For this purpose, we analyzed the occurrence of types of ectomycorrhizae on beech seedlings in rhizotrons exposed to fo...

  5. RELATIONSHIPS BETWEEN EASTERN BEECH FORESTS STAND PARAMETERS AND LANDSAT ETM SPECTRAL RESPONSES IN TURKEY

    OpenAIRE

    Ateşoğlu, Ayhan; TUNAY, Metin

    2013-01-01

    This paper explores relationships between forest stand parameters and Landsat Enhancement Thematic Mapper (ETM), atmospheric correction applied, spectral responses thorough analyses of study area in Mugada, Bartin and its vicinity where natural beech (Fagus orientalis L.) stands. ETM bands and many vegetation indices were examined thorough integration of spectral responses and field vegetation inventory data. Pearson’s correlation coefficients were used to interpret relationships between fore...

  6. Harvested wood products and carbon sink in a young beech high forest

    OpenAIRE

    Pilli R; Dalla Valle E; Anfodillo T; Fontanella F; Penzo D

    2008-01-01

    According to art. 3.4 of the Kyoto Protocol (KP), Italy has elected forest management as additional human-induced activity to attain the goal of reduction in greenhouse gas emissions. The whole forest area not subjected to afforestation, reforestation or deforestation processes since 1990 will be considered as managed forest. In order to analyse different management strategies, the Carbon-Pro Project, involving 9 partners of the European CADSES area, considered a young beech high forest (ex-c...

  7. Finite Changes of Bound Water Moisture Content in a Given Volume of Beech Wood

    OpenAIRE

    Richard Hrčka

    2016-01-01

    The undesired wood instabilities are connected with the changes of bound water moisture content. The rates of finite changes of bound water moisture content in a given volume of wood were determined in the frame of the specimen dimensions. The derivation is based on the 1st Fick’s law and diffusion equation solution in three dimensions. The inverse solution of diffusion equation provided the diffusion coefficients in the principal anatomical directions. Beech wood was tested. The nonlinear re...

  8. Comparative phylogeography of two sympatric beeches in subtropical China: Species-specific geographic mosaic of lineages

    OpenAIRE

    Zhang, Zhi-Yong; Wu, Rong; Wang, Qun; Zhang, Zhi-rong; López-Pujol, Jordi; Fan, Deng-Mei; Li, De-Zhu

    2013-01-01

    In subtropical China, large-scale phylogeographic comparisons among multiple sympatric plants with similar ecological preferences are scarce, making generalizations about common response to historical events necessarily tentative. A phylogeographic comparison of two sympatric Chinese beeches (Fagus lucida and F. longipetiolata, 21 and 28 populations, respectively) was conducted to test whether they have responded to historical events in a concerted fashion and to determine whether their phylo...

  9. Conversion of Mountain Beech Coppices into High Forest: An Example for Ecological Intensification.

    Science.gov (United States)

    Mattioli, Walter; Ferrari, Barbara; Giuliarelli, Diego; Mancini, Leone Davide; Portoghesi, Luigi; Corona, Piermaria

    2015-11-01

    Converting beech coppices into high forest stands has been promoted in the last decades as a management goal to attenuate the negative effects that frequent clearcutting may have on soil, landscape, and biodiversity conservation. The silvicultural tool usually adopted is the gradual thinning of shoots during the long span of time required to complete the conversion, that also allows the owner to keep harvesting some wood. This research reports and discusses, in the light of the ecological intensification approach, the results achieved from an experimental test started more than 25 years ago in a 42-year-old beech (Fagus sylvatica L.) coppice with standards in central Italy. The effects of various thinning intensities (three treatments plus a control) on the stand growth and structure are assessed by successive forest inventories. Analyses are integrated by spatial indices to assess stem density and canopy cover. Converting beech coppices into high forest through gradual thinning of shoots proves to be an effective step down the road to silvicultural systems characterized by continuous forest cover, as a tool of ecological intensification suitable to guarantee both public and private interests. Thinning has led to stands with fewer but larger stems, thus accelerating the long conversion process while maintaining both wood harvesting capability and environmental services.

  10. Conversion of Mountain Beech Coppices into High Forest: An Example for Ecological Intensification

    Science.gov (United States)

    Mattioli, Walter; Ferrari, Barbara; Giuliarelli, Diego; Mancini, Leone Davide; Portoghesi, Luigi; Corona, Piermaria

    2015-11-01

    Converting beech coppices into high forest stands has been promoted in the last decades as a management goal to attenuate the negative effects that frequent clearcutting may have on soil, landscape, and biodiversity conservation. The silvicultural tool usually adopted is the gradual thinning of shoots during the long span of time required to complete the conversion, that also allows the owner to keep harvesting some wood. This research reports and discusses, in the light of the ecological intensification approach, the results achieved from an experimental test started more than 25 years ago in a 42-year-old beech ( Fagus sylvatica L.) coppice with standards in central Italy. The effects of various thinning intensities (three treatments plus a control) on the stand growth and structure are assessed by successive forest inventories. Analyses are integrated by spatial indices to assess stem density and canopy cover. Converting beech coppices into high forest through gradual thinning of shoots proves to be an effective step down the road to silvicultural systems characterized by continuous forest cover, as a tool of ecological intensification suitable to guarantee both public and private interests. Thinning has led to stands with fewer but larger stems, thus accelerating the long conversion process while maintaining both wood harvesting capability and environmental services.

  11. Changes Caused by Heat Treatment in Color and Dimensional Stability of Beech (Fagus sylvatica L. Wood

    Directory of Open Access Journals (Sweden)

    Ioannis Barboutis

    2014-09-01

    Full Text Available Thermal modification of wood permanently alters several of its chemical and physical properties. Beech wood is one of the most important hardwoods in Central and Eastern Europe and is extensively used in furniture production. In this study the effects of thermal modification of beech wood (Fagus sylvatica L. on hygroscopic properties were examined and the color changes of the treated wood were determined. Beech wood has been subjected to a heat treatment at the temperature of 180 °C for five different durations ranging from 2 to 10 h. A more intense, gradual color change of the treated samples was observed after 4-h treatment, whereas in some other cases the recorded alterations were less intense. The most pronounced color differentiations compared to untreated samples occurred in 8-h and 10-h treatments. Dimensional stability and absorption were measured after 1-h, 3-h, 6-h, 1 day and 3 days immersion in water. The 8-h treatment duration exhibits the greatest reduction of swelling and absorption percentage.

  12. Canopy carbon budget of Siebold's beech (Fagus crenata) sapling under free air ozone exposure

    International Nuclear Information System (INIS)

    To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol−1, during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons. -- Highlights: • Upper canopy leaf of Siebold's beech is sensitive to ozone. • The net carbon gain of canopy was reduced by ozone. • Enhanced respiration by ozone highly contributes to net carbon gain in late summer. -- Contributions of ozone-induced reduction in photosynthesis and increase in respiration to canopy net carbon gain of beech sapling were different between seasons

  13. Status and trend of tree growth and mortality rate at the CONECOFOR plots, 1997-2004

    Directory of Open Access Journals (Sweden)

    Gianfranco Fabbio

    2013-11-01

    Full Text Available The circumference of trees in the CONECOFOR permanent monitoring plots (PMPs were measured by three surveys carried out in 1997, 2000 and 2005. Plots were arranged into forest types according to tree species, management system and stand structure: beech (Fagus sylvatica L. and spruce (Picea abies K. high forests, aged coppice forests and transitory crops (deciduous, evergreen oaks and beech. Diameter distribution, basal area, basal area increment, tree mortality rate and in-growth were calculated per layer (dominant, intermediate, dominated within each PMP, to point out relative contributions and changes. A range in relative annual growth was detected both within and between types over the monitored period, but an obvious reduction of annual increment was found in two/thirds of plots over 2000-04 as compared to 1997-99. Current mortality, mostly allocated into the dominated and intermediate layers, can be explained as “regular” due to overstocking and high inter-tree competition in almost all of the observed case-studies. Opposite patterns were found to occur as for stand growth vs. mortality rate between coppice forests and the other types owing to the different dynamics of tree competition in progress. Drought 2003 is the likely large-scale factor determining the reduced annual growth course over the second period.

  14. Holy Trees

    OpenAIRE

    Elosua, Miguel

    2013-01-01

    Puxi's streets are lined with plane trees, especially in the former French Concession (and particularly in the Luwan and Xuhui districts). There are a few different varieties of plane tree, but the one found in Shanghai, is the hybrid platane hispanica. In China they are called French Plane trees (faguo wutong - 法国梧桐), for they were first planted along the Avenue Joffre (now Huai Hai lu - 淮海路) in 1902 by the French. Their life span is long, over a thousand years, and they may grow as high as ...

  15. Effects of elevated pO3 on carbon cycle between above and belowground organs of trees

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-ping; Rennenberg Heinz; Matyssek Rainer

    2006-01-01

    Translocation of carbohydrate from leaves to roots via phloem and reallocation from roots to leaves via xylem regulate the allocation of carbon (C) between above and belowground organs of trees. To quantitatively analyze effects of elevated ozone concentrations pO3 on the internal cycle of C, juvenile beech and spruce were grown in phytotrons and exposed to ambient and elevated pO3 (i.e. twice-ambient O3 levels, restricted to < 150 ppb) for two growing seasons. The translocation of C in the phloem and xylem was quantitatively studied by investigating the phloem/xylem-loading of sugars, the differentiation of stem conductive tissue and the hourly water flow through the stem. Results in the present study shown, elevated pO3 significantly decreased C translocation from shoot to roots in beech by reducing both sugar concentration in the phloem and conductive phloem area. Elevated pO3 also significantly decreased C reallocation from the roots to the shoot in beech by reducing both of sugar concentration in the xylem and transpiration rate. The adverse effects of elevated pO3 on C translocation in the phloem and xylem, however, were small in spruce.Contrasting to beech, spruce is less sensitive to elevated pO3, regarding to phloem differentiation and sugar concentrations in the phloem and xylem.

  16. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  17. Game tree algorithms and solution trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie)

    1998-01-01

    textabstractIn this paper, a theory of game tree algorithms is presented, entirely based upon the concept of solution tree. Two types of solution trees are distinguished: max and min trees. Every game tree algorithm tries to prune nodes as many as possible from the game tree. A cut-off criterion in

  18. Temporal variability of the NPP-GPP ratio at seasonal and interannual time scales in a temperate beech forest

    Directory of Open Access Journals (Sweden)

    M. Campioli

    2011-09-01

    Full Text Available The allocation of carbon (C taken up by the tree canopy for respiration and production of tree organs with different construction and maintenance costs, life span and decomposition rate, crucially affects the residence time of C in forests and their C cycling rate. The carbon-use efficiency, or ratio between net primary production (NPP and gross primary production (GPP, represents a convenient way to analyse the C allocation at the stand level. In this study, we extend the current knowledge on the NPP-GPP ratio in forests by assessing the temporal variability of the NPP-GPP ratio at interannual (for 8 years and seasonal (for 1 year scales for a young temperate beech stand, reporting dynamics for both leaves and woody organs, in particular stems. NPP was determined with biometric methods/litter traps, whereas the GPP was estimated via the eddy covariance micrometeorological technique.

    The interannual variability of the proportion of C allocated to leaf NPP, wood NPP and leaf plus wood NPP (on average 11% yr−1, 29% yr−1 and 39% yr−1, respectively was significant among years with up to 12% yr−1 variation in NPP-GPP ratio. Studies focusing on the comparison of NPP-GPP ratio among forests and models using fixed allocation schemes should take into account the possibility of such relevant interannual variability. Multiple linear regressions indicated that the NPP-GPP ratio of leaves and wood significantly correlated with environmental conditions. Previous year drought and air temperature explained about half of the NPP-GPP variability of leaves and wood, respectively, whereas the NPP-GPP ratio was not decreased by severe drought, with large NPP-GPP ratio on 2003 due mainly to low GPP. During the period between early May and mid June, the majority of GPP was allocated to leaf and stem NPP, whereas these sinks were of little importance later on. Improved estimation of seasonal GPP and of the

  19. Temporal variability of the NPP-GPP ratio at seasonal and interannual time scales in a temperate beech forest

    Science.gov (United States)

    Campioli, M.; Gielen, B.; Göckede, M.; Papale, D.; Bouriaud, O.; Granier, A.

    2011-09-01

    The allocation of carbon (C) taken up by the tree canopy for respiration and production of tree organs with different construction and maintenance costs, life span and decomposition rate, crucially affects the residence time of C in forests and their C cycling rate. The carbon-use efficiency, or ratio between net primary production (NPP) and gross primary production (GPP), represents a convenient way to analyse the C allocation at the stand level. In this study, we extend the current knowledge on the NPP-GPP ratio in forests by assessing the temporal variability of the NPP-GPP ratio at interannual (for 8 years) and seasonal (for 1 year) scales for a young temperate beech stand, reporting dynamics for both leaves and woody organs, in particular stems. NPP was determined with biometric methods/litter traps, whereas the GPP was estimated via the eddy covariance micrometeorological technique. The interannual variability of the proportion of C allocated to leaf NPP, wood NPP and leaf plus wood NPP (on average 11% yr-1, 29% yr-1 and 39% yr-1, respectively) was significant among years with up to 12% yr-1 variation in NPP-GPP ratio. Studies focusing on the comparison of NPP-GPP ratio among forests and models using fixed allocation schemes should take into account the possibility of such relevant interannual variability. Multiple linear regressions indicated that the NPP-GPP ratio of leaves and wood significantly correlated with environmental conditions. Previous year drought and air temperature explained about half of the NPP-GPP variability of leaves and wood, respectively, whereas the NPP-GPP ratio was not decreased by severe drought, with large NPP-GPP ratio on 2003 due mainly to low GPP. During the period between early May and mid June, the majority of GPP was allocated to leaf and stem NPP, whereas these sinks were of little importance later on. Improved estimation of seasonal GPP and of the contribution of previous-year reserves to stem growth, as well as reduction

  20. Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L.) stand in south-eastern Germany based on repeated digital photographs

    Science.gov (United States)

    Menzel, Annette; Helm, Raimund; Zang, Christian

    2015-04-01

    The seasonality of woody plants in cold and temperate climates is adapted to the annual course of temperature and photoperiod in order to maximise the length of the active growing season and, at the same time, avoid damages by frost events, especially by late spring frosts. Winter chilling, spring warming and finally photoperiod trigger the timely bud burst of European beech (Fagus sylvatica L.) which as a climax species is quite sensitive to winter frost and also as seedling to late spring frosts. However, due to relatively late and less varying dates of leaf unfolding, damages by late spring frosts should not occur each year. In case of a total loss due to a late frost event, F. sylvatica trees produce a new set of leaves which guarantees survival, but diminishes carbon reserves. With a phenological camera we observed the phenological course of such an extreme event in the Nationalpark Bayerischer Wald in May 2011: Spring leaf unfolding, an almost complete loss of fresh green leaves after the frost event in the night 3rd to 4th May, a subsequent leafless period followed by re-sprouting. We modeled this special leaf development from day 80 to 210, observed as green% from the repeated digital camera pictures, using the Bayesian multiple change point approach recently introduced by Henneken et al. (2013). The results for more than 30 trees predominantly suggested a model with five change points: firstly, start of the season, abrupt ending before the frost event, the loss by the frost event and after a longer period of recovery the second leaf unfolding (St. John's sprout) ending in full leaf maturity. Analyzing the results of these models the following questions were answered (1) how long is the period of recovery till the second green-up? (2) does the temporal course of the second leafing differ from the first one? (3) what are the individual factors influencing damage and recovery? (4) are individuals with early or late bud burst more prone to damage? The five

  1. Does reduced precipitation trigger physiological and morphological drought adaptations in European beech (Fagus sylvatica L.)? Comparing provenances across a precipitation gradient.

    Science.gov (United States)

    Knutzen, Florian; Meier, Ina Christin; Leuschner, Christoph

    2015-09-01

    Global warming and associated decreases in summer rainfall may threaten tree vitality and forest productivity in many regions of the temperate zone in the future. One option for forestry to reduce the risk of failure is to plant genotypes which combine high productivity with drought tolerance. Growth experiments with provenances from different climates indicate that drought exposure can trigger adaptive drought responses in temperate trees, but it is not well known whether and to what extent regional precipitation reduction can increase the drought resistance of a species. We conducted a common garden growth experiment with five European beech (Fagus sylvatica L.) populations from a limited region with pronounced precipitation heterogeneity (816-544 mm year(-1)), where phylogenetically related provenances grew under small to large water deficits. We grew saplings of the five provenances at four soil moisture levels (dry to moist) and measured ∼30 morphological (leaf and root properties, root : shoot ratio), physiological (leaf water status parameters, leaf conductance) and growth-related traits (above- and belowground productivity) with the aim to examine provenance differences in the drought response of morphological and physiological traits and to relate the responsiveness to precipitation at origin. Physiological traits were more strongly influenced by provenance (one-third of the studied traits), while structural traits were primarily affected by water availability in the experiment (two-thirds of the traits). The modulus of leaf tissue elasticity ϵ reached much higher values late in summer in plants from moist origins resulting in more rapid turgor loss and a higher risk of hydraulic failure upon drought. While experimental water shortage affected the majority of morphological and productivity-related traits in the five provenances, most parameters related to leaf water status were insensitive to water shortage. Thus, plant morphology, and root

  2. Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L. stand in south-eastern Germany based on repeated digital photographs

    Directory of Open Access Journals (Sweden)

    Annette eMenzel

    2015-02-01

    Full Text Available Damage by late spring frost is a risk deciduous trees have to cope with in order to optimize the length of their growing season. The timing of spring phenological development plays a crucial role, not only at the species level, but also at the population and individual level, since fresh new leaves are especially vulnerable. For the pronounced late spring frost in May 2011 in Germany, we studied the individual leaf development of 35 deciduous trees (mainly European beech Fagus sylvatica L. at a mountainous forest site in the Bayerischer Wald National Park using repeated digital photographs. Analyses of the time series of greenness by a novel Bayesian multiple change point approach mostly revealed five change points which almost perfectly matched the expected break points in leaf development: i start of the first greening between DOY (day of the year 108 to 119 (mean 113, ii end of greening and iii visible frost damage after the frost on the night of May 3rd/4th (DOY 123, 124, iv re-sprouting 19 to 38 days after the frost, and v full maturity around DOY 178 (166 to 184 when all beech crowns had fully recovered. Since frost damage was nearly 100%, individual susceptibility did not depend on the timing of first spring leaf unfolding. However, we could identify significant patterns in fitness linked to an earlier start of leaf unfolding. Those individuals that had an earlier start of greening during the first flushing period had a shorter period of recovery and started the second greening earlier. Thus, phenological timing triggered the speed of recovery from such an extreme event. The maximum greenness achieved, however, did not vary with leaf unfolding dates. Two mountain ashes (Sorbus aucuparia L. were not affected by the low temperatures of −5°C. Time series analysis of webcam pictures can thus improve process-based knowledge and provide valuable insights into the link between phenological variation, late spring frost damage and recovery

  3. Patterns of late spring frost leaf damage and recovery in a European beech (Fagus sylvatica L.) stand in south-eastern Germany based on repeated digital photographs.

    Science.gov (United States)

    Menzel, Annette; Helm, Raimund; Zang, Christian

    2015-01-01

    Damage by late spring frost is a risk deciduous trees have to cope with in order to optimize the length of their growing season. The timing of spring phenological development plays a crucial role, not only at the species level, but also at the population and individual level, since fresh new leaves are especially vulnerable. For the pronounced late spring frost in May 2011 in Germany, we studied the individual leaf development of 35 deciduous trees (mainly European beech Fagus sylvatica L.) at a mountainous forest site in the Bayerischer Wald National Park using repeated digital photographs. Analyses of the time series of greenness by a novel Bayesian multiple change point approach mostly revealed five change points which almost perfectly matched the expected break points in leaf development: (i) start of the first greening between day of the year (DOY) 108-119 (mean 113), (ii) end of greening, and (iii) visible frost damage after the frost on the night of May 3rd/4th (DOY 123/124), (iv) re-sprouting 19-38 days after the frost, and (v) full maturity around DOY 178 (166-184) when all beech crowns had fully recovered. Since frost damage was nearly 100%, individual susceptibility did not depend on the timing of first spring leaf unfolding. However, we could identify significant patterns in fitness linked to an earlier start of leaf unfolding. Those individuals that had an earlier start of greening during the first flushing period had a shorter period of recovery and started the second greening earlier. Thus, phenological timing triggered the speed of recovery from such an extreme event. The maximum greenness achieved, however, did not vary with leaf unfolding dates. Two mountain ashes (Sorbus aucuparia L.) were not affected by the low temperatures of -5°C. Time series analysis of webcam pictures can thus improve process-based knowledge and provide valuable insights into the link between phenological variation, late spring frost damage, and recovery within one stand

  4. Tree Species Specific Soil Moisture Patterns and Dynamics

    Science.gov (United States)

    Heidbuechel, I.; Dreibrodt, J.; Guntner, A.; Blume, T.

    2014-12-01

    Land use has a major influence on the hydrologic processes that take place in soils. Soil compaction on pastures for example leads to infiltration patterns that differ considerably from the ones observable in forests. It is not clear, however, how different forest stands influence soil infiltration and soil moisture distributions. Factors that that vary amongst different stands and potentially affect soil moisture processes in forests are, amongst others, canopy density, throughfall patterns, the intensity and frequency of stem flow, litter type, root distributions and rooting depth. To investigate how different tree species influence the way soils partition, store and conduct incoming precipitation we selected 15 locations under different tree stands within the TERENO observatory in north-east Germany. The forest stands under investigation were mature oak, young pine, mature pine, young beech and mature beech. At each location we installed 30 FDR soil moisture sensors grouped into five depth profiles (monitoring soil moisture from 10 cm to 200 cm) and 5 additional near surface sensors. The profile locations within each forest stand covered most of the anticipated variability by ranging from minimum to maximum distance to the trees including locations under more and less dense canopy. Supplementary to the FDR sensors, throughfall measurements, tensiometers and groundwater data were available to observe dynamics of tree water availability, water fluxes within the soils and percolation towards the groundwater. To identify patterns in space and time we referred to the statistical methods of wavelet analysis and temporal stability analysis. Finally, we tried to link the results from these analyses to specific hydrologic processes at the different locations.

  5. Pollution and Climate Effects on Tree-Ring Nitrogen Isotopes

    Science.gov (United States)

    Savard, M. M.; Bégin, C.; Marion, J.; Smirnoff, A.

    2009-04-01

    BACKGROUND Monitoring of nitrous oxide concentration only started during the last 30 years in North America, but anthropogenic atmospheric nitrogen has been significantly emitted over the last 150 years. Can geochemical characteristics of tree rings be used to infer past changes in the nitrogen cycle of temperate regions? To address this question we use nitrogen stable isotopes in 125 years-long ring series from beech specimens (Fagus grandifolia) of the Georgian Bay Islands National Park (eastern Ontario), and pine (Pinus strobus) and beech trees of the Arboretum Morgan near Montreal (western Quebec). To evaluate the reliability of the N stable isotopes in wood treated for removal of soluble materials, we tested both tree species from the Montreal area. The reproducibility from tree to tree was excellent for both pine and beech trees, the isotopic trends were strongly concordant, and they were not influenced by the heartwood-sapwood transition zone. The coherence of changes of the isotopic series observed for the two species suggests that their tree-ring N isotopic values can serve as environmental indicator. RESULTS AND INTERPRETATION In Montreal and Georgian Bay, the N isotopes show strong and similar parallel agreement (Gleichlaufigkeit test) with the climatic parameters. So in fact, the short-term isotopic fluctuations correlate directly with summer precipitation and inversely with summer and spring temperature. A long-term decreasing isotope trend in Montreal indicates progressive changes in soil chemistry after 1951. A pedochemical change is also inferred for the Georgian Bay site on the basis of a positive N isotopic trend initiated after 1971. At both sites, the long-term ^15N series correlate with a proxy for NOx emissions (Pearson correlation), and carbon-isotope ring series suggest that the same trees have been impacted by phytotoxic pollutants (Savard et al., 2009a). We propose that the contrasted long-term nitrogen-isotope changes of Montreal and

  6. Soil carbon accumulation and nitrogen retention traits of four tree species grown in common gardens

    DEFF Research Database (Denmark)

    Gurmesa, Geshere Abdisa; Schmidt, Inger Kappel; Gundersen, Per;

    2013-01-01

    Tree species effects on soil carbon (C) accumulation are uncertain, especially with respect to the mineral soil C, and the consistency of such effects across soil types is not known. The interaction between C accumulation and nitrogen (N) retention among common tree species has also been little...... explored. Effects of four tree species on soil C and N stocks and soil water nitrate concentration below the root zone were evaluated in a common garden design replicated at eight sites in Denmark. The tree species were beech (Fagus sylvatica L.), oak (Quercus robur L.), larch (Larix leptolepis Kaempf......), and Norway spruce (Picea abies (L) Karst.). After four decades, there were significant differences in forest floor C stocks among all four species, and C stocks increased consistently in the order oak

  7. Interpreting Tree Ensembles with inTrees

    OpenAIRE

    Deng, Houtao

    2014-01-01

    Tree ensembles such as random forests and boosted trees are accurate but difficult to understand, debug and deploy. In this work, we provide the inTrees (interpretable trees) framework that extracts, measures, prunes and selects rules from a tree ensemble, and calculates frequent variable interactions. An rule-based learner, referred to as the simplified tree ensemble learner (STEL), can also be formed and used for future prediction. The inTrees framework can applied to both classification an...

  8. Structural research in the natural beech forest, situated at the eastern limit (Humosu Old Growth Beech Forest, Iași county, Romania

    Directory of Open Access Journals (Sweden)

    Flutur Gheorghe

    2010-11-01

    Full Text Available The paper points out the stability of the natural forest due to its structural complexity, reachedthrough milennia of evolution. The „Humosu Old Growth Beech Forest” situated between 450-500m altitudein the Moldavian Plateau is a clear example of a natural structure with a continuous transformation given bythe passage through a series of stages (phases with individual characteristics. Five of these individualphases are identified and described: the initial phase, the optimal phase, the terminal phase, the degradationphase and the regeneration phase. For each of these phases biometric characteristics are indicated, and thegeneral structural profile, as well. The distribution of dead wood volume inside these phases, as part of anatural matter circuit, found in different stages of degradation, shows the complexity of natural ecosystemsand their importance to life, in general.

  9. Social valuation of scenic beauty in Catalonian beech forests; Valoracion social de las propiedades esteticas de los hayedos en Cataluna

    Energy Technology Data Exchange (ETDEWEB)

    Vega-Garcia, C.; Burriel, M.; Alcazar, J.

    2011-07-01

    Methods tested in other countries are applied for scenic beauty valuation in several beech locations in Catalonia including significant differences in site, origin, age and stand structure. The study intends to measure stand scenic beauty as seen from inside the forest, as forest visitors see it (near-view). Assessments are obtained through panels of observers in slide sessions, which are transformed into scaled ratings and related through regression analysis to plot-based forest inventory data. The development of statistical models that describe social visual preferences allows the assessment of the contribution of different forestry-related physical variables to the aesthetic improvement of beech forests. It can also be useful as a guide to beech forest planning where recreational use is prevailing or very important. (Author) 37 refs.

  10. Contributions to the phytocoenologic study in pure european beech stand forests in Codru-Moma Mountains (North-Western Romania

    Directory of Open Access Journals (Sweden)

    Călin-Gheorghe PĂŞCUŢ

    2010-05-01

    Full Text Available In the present work we present a phytocoenologic study on the associations found in pure European beech stand forests in Codru-Moma Mountains namely: Festuco drymejae-Fagetum Morariu et al. 1968, Luzulo albidae-Fagetum sylvaticae Zólyomi 1955.Characterization of the associations we studied and presentation of the tables have been made considering the selection of the most representative relevées of pure European beech forests belonging to Codru-Moma Mountains.The phytocoenoses of pure forest stands of European beech forests belonging to the two associations were analyzed in terms of floristic composition, life forms spectrum, spectrum chart of the floral elements and ecological indices.

  11. Competitive strategies in adult beech and spruce: space-related foliar carbon investment versus carbon gain.

    Science.gov (United States)

    Reiter, I M; Häberle, K-H; Nunn, A J; Heerdt, C; Reitmayer, H; Grote, R; Matyssek, R

    2005-12-01

    In Central Europe, Fagus sylvatica and Picea abies represent contrasting extremes in foliage type, crown structure and length of growing season. In order to examine the competitive strategies of these two co-occurring species, we tested the following hypotheses: (1) the space occupied by the foliage of sun branches is characterized by greater foliar mass investment compared to shade branches, (2) the carbon (C) gain per unit of occupied space is greater in sun than in shade branches, and (3) annual C and water costs of the foliage for sustaining the occupied space are low, wherever C gain per unit of occupied space is low. These were investigated in a mature forest in Southern Germany. The examination was based on the annual assessment of space-related resource investments and gains of the foliage. The foliated space around branches was regarded as the relevant volume with respect to aboveground resource availability. Occupied crown space per standing foliage mass was higher in shade compared to sun branches of beech, whereas no difference existed in crown volume per foliage mass between sun and shade branches of spruce (hypothesis 1 accepted for beech but rejected for spruce). However, beech occupied more space per foliage mass than spruce. The C gain per occupied crown volume was greater in sun than in shade branches (hypothesis 2 accepted) but did not differ between species. The amount of occupied space per respiratory and transpiratory costs did not differ between species or between sun and shade branches. In beech and spruce, the proportion of foliage investment in the annual C balance of sun and shade branches remained rather stable, whereas respiratory costs distinctly increased in shade foliage. Hence, shade branches were costly structures to occupy space, achieving only low and even negative C balances (rejection of hypothesis 3), which conflicts with the claimed C autonomy of branches. Our findings suggest that competitiveness is determined by the

  12. Molten salt pyrolysis of milled beech wood using an electrostatic precipitator for oil collection

    OpenAIRE

    Nygård, Heidi S.; Espen Olsen

    2015-01-01

    A tubular electrostatic precipitator (ESP) was designed and tested for collection of pyrolysis oil in molten salt pyrolysis of milled beech wood (0.5-2 mm). The voltage-current (V-I) characteristics were studied, showing most stable performance of the ESP when N2 was utilized as inert gas. The pyrolysis experiments were carried out in FLiNaK and (LiNaK)2CO3 over the temperature range of 450-600 ℃. The highest yields of pyrolysis oil were achieved in FLiNaK, with a maximum of 34.2 wt% at 500 ℃...

  13. Leaf area index from litter collection: impact of specific leaf area variability within a beech stand

    International Nuclear Information System (INIS)

    Litter fall collection is a direct method widely used to estimate leaf area index (LAI) in broad-leaved forest stands. Indirect measurements using radiation transmittance and gap fraction theory are often compared and calibrated against litter fall, which is considered as a reference method, but few studies address the question of litter specific leaf area (SLA) measurement and variability. SLA (leaf area per unit of dry weight, m2·g-1) is used to convert dry leaf litter biomass (g .m-2) into leaf area per ground unit area (m2·m-2). We paid special attention to this parameter in two young beech stands (dense and thinned) in northeastern France. The variability of both canopy (closure, LAI) and site conditions (soil properties, vegetation) was investigated as potential contributing factors to beech SLA variability. A systematic description of soil and floristic composition was performed and three types of soil were identified. Ellenberg's indicator values were averaged for each plot to assess nitrogen soil content. SLA of beech litter was measured three times during the fall in 23 plots in the stands (40 ha). Litter was collected bimonthly in square-shaped traps (0.5 m2) and dried. Before drying, 30 leaves per plot and for each date were sampled, and leaf length, width, and area were measured with the help of a LI-COR areameter. SLA was calculated as the ratio of cumulated leaf area to total dry weight of the 30 leaves. Leaves characteristics per plot were averaged for the three dates of litter collection. Plant area index (PAI), estimated using the LAI-2000 plant canopy analyser and considering only the upper three rings, ranged from 2.9 to 8.1. Specific leaf area of beech litter was also highly different from one plot to the other, ranging from 150 to 320 cm2·g-1. Nevertheless, no relationship was found between SLA and stand canopy closure or PAI On the contrary, a significant relationship between SLA and soil properties was observed. Both SLA and leaf area had

  14. Pyrolysis reactions of Japanese cedar and Japanese beech woods in a closed ampoule reactor

    OpenAIRE

    Asmadi, Mohd; Kawamoto, Haruo; Saka, Shiro

    2010-01-01

    The chemical structures of hemicellulose and lignin are different for two distinct types of wood, i.e., softwood and hardwood. Such differences are expected to affect pyrolysis behavior. In this article, the differences are discussed for Japanese cedar wood (a softwood) and Japanese beech wood (a hardwood) pyrolyzed in a closed ampoule reactor (N2/600°C/40–600 s). Oven-dried samples were used to eliminate the influence of initial water. Demineralized samples (prepared by acid washing) were al...

  15. Aspen Trees.

    Science.gov (United States)

    Canfield, Elaine

    2002-01-01

    Describes a fifth-grade art activity that offers a new approach to creating pictures of Aspen trees. Explains that the students learned about art concepts, such as line and balance, in this lesson. Discusses the process in detail for creating the pictures. (CMK)

  16. The influence of tree traits and storm event characteristics on stemflow production from isolated deciduous trees in an urban park

    Science.gov (United States)

    Carlyle-Moses, D. E.; Schooling, J. T.

    2014-12-01

    Urban tree canopy processes affect the volume and biogeochemistry of inputs to the hydrological cycle in cities. We studied stemflow from 37 isolated deciduous trees in an urban park in Kamloops, British Columbia which has a semi-arid climate dominated by small precipitation events. Precipitation and stemflow were measured on an event basis from June 12, 2012 to November 3, 2013. To clarify the effect of canopy traits on stemflow thresholds, rates, yields, percent, and funneling ratios, we analyzed branch angles, bark roughness, tree size, cover, leaf size, and branch and leader counts. High branch angles promoted stemflow in all trees, while bark roughness influenced stemflow differently for single- and multi-leader trees. The association between stemflow and numerous leaders deserves further study. Columnar-form trees often partitioned a large percentage of precipitation into stemflow, with event-scale values as high as 27.9 % recorded for an Armstrong Freeman Maple (Acer x freemanii 'Armstrong'). Under growing-season conditions funneling ratios as high as 196.9 were derived for an American Beech (Fagus grandifolia) individual. Among meteorological variables, rain depth was strongly correlated with stemflow yields; intra-storm break duration, rainfall intensity, rainfall inclination, wind speed, and vapour pressure deficit also played roles. Greater stemflow was associated with leafless canopies and with rain or mixed events versus snow. Results can inform climate-sensitive selection and siting of urban trees towards integrated rainwater management. For example, previous studies suggest that the reduction in storm-water generation by urban trees is accomplished through canopy interception loss alone. However, trees that partition large quantities of precipitation canopy-drainage as stemflow to the base of their trunks, where it has the potential to infiltrate into the soil media rather than fall on impervious surfaces as throughfall, may assist in reducing

  17. Tree Species Classification By Multiseasonal High Resolution Satellite Data

    Science.gov (United States)

    Elatawneh, Alata; Wallner, Adelheid; Straub, Christoph; Schneider, Thomas; Knoke, Thomas

    2013-12-01

    Accurate forest tree species mapping is a fundamental issue for sustainable forest management and planning. Forest tree species mapping with the means of remote sensing data is still a topic to be investigated. The Bavaria state institute of forestry is investigating the potential of using digital aerial images for forest management purposes. However, using aerial images is still cost- and time-consuming, in addition to their acquisition restrictions. The new space-born sensor generations such as, RapidEye, with a very high temporal resolution, offering multiseasonal data have the potential to improve the forest tree species mapping. In this study, we investigated the potential of multiseasonal RapidEye data for mapping tree species in a Mid European forest in Southern Germany. The RapidEye data of level A3 were collected on ten different dates in the years 2009, 2010 and 2011. For data analysis, a model was developed, which combines the Spectral Angle Mapper technique with a 10-fold- cross-validation. The analysis succeeded to differentiate four tree species; Norway spruce (Picea abies L.), Silver Fir (Abies alba Mill.), European beech (Fagus sylvatica) and Maple (Acer pseudoplatanus). The model success was evaluated using digital aerial images acquired in the year 2009 and inventory point records from 2008/09 inventory. Model results of the multiseasonal RapidEye data analysis achieved an overall accuracy of 76%. However, the success of the model was evaluated only for all the identified species and not for the individual.

  18. Effect of livestock grazing and human uses on herbaceous species diver-sity in oriental beech (Fagus orientalis Lipsky) forests, Guilan, Masal, northern Iran

    Institute of Scientific and Technical Information of China (English)

    Sepide Sadat Ebrahimi; Hassan Pourbabaei; David Potheir; Ali Omidi; Javad Torkaman

    2014-01-01

    Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of pro-tected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech (Fagus orientalis Lipsky) forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H (Shan-non-Wiener index ), N1 (McArthur index), N2 (Hill΄s index), EQ (Modified Nee index), Evar (Smith-Wilson index), E5 (modified index of Hill) and R=S (species richness) and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and even-ness indices was higher than that between diversity and richness.

  19. Age-related changes in protein metabolism of beech (Fagus sylvatica L.) seeds during alleviation of dormancy and in the early stage of germination.

    Science.gov (United States)

    Ratajczak, Ewelina; Kalemba, Ewa M; Pukacka, Stanislawa

    2015-09-01

    The long-term storage of seeds generally reduces their viability and vigour. The aim of this work was to evaluate the effect of long-term storage on beech (Fagus sylvatica L.) seeds at optimal conditions, over 9 years, on the total and soluble protein levels and activity of proteolytic enzymes, including endopeptidases, carboxypeptidases and aminopeptidases, as well as free amino acid levels and protein synthesis, in dry seeds, after imbibition and during cold stratification leading to dormancy release and germination. The same analyses were conducted in parallel on seeds gathered from the same tree in the running growing season and stored under the same conditions for only 3 months. The results showed that germination capacity decreased from 100% in freshly harvested seeds to 75% in seeds stored for 9 years. The levels of total and soluble proteins were highest in freshly harvested seeds and decreased significantly during storage, these proportions were retained during cold stratification and germination of seeds. Significant differences between freshly harvested and stored seeds were observed in the activities of proteolytic enzymes, including endopeptidases, aminopeptidases and carboxypeptidases, and in the levels of free amino acids. The neosynthesis of proteins during dormancy release and in the early stage of seed germination was significantly weaker in stored seeds. These results confirm the importance of protein metabolism for seed viability and the consequences of its reduction during seed ageing.

  20. Unimodular trees versus Einstein trees

    Science.gov (United States)

    Álvarez, Enrique; González-Martín, Sergio; Martín, Carmelo P.

    2016-10-01

    The maximally helicity violating tree-level scattering amplitudes involving three, four or five gravitons are worked out in Unimodular Gravity. They are found to coincide with the corresponding amplitudes in General Relativity. This a remarkable result, insofar as both the propagators and the vertices are quite different in the two theories.

  1. Atmospheric deposition in coniferous and deciduous tree stands in Poland

    Science.gov (United States)

    Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

    2016-05-01

    The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

  2. Tree species specific soil moisture patterns and dynamics through the seasons

    Science.gov (United States)

    Heidbüchel, Ingo; Dreibrodt, Janek; Simard, Sonia; Güntner, Andreas; Blume, Theresa

    2015-04-01

    Soil moisture patterns in the landscape are largely controlled by soil types (pore size distributions) and landscape position. But how strong is the influence of vegetation on patterns within a single soil type? While we would envision a clear difference in soil moisture patterns and responses between for example bare soil, a pasture and a forest, our conceptual images start to become less clear when we move on to different forest stands. Do different tree species cause different moisture patterns to emerge? Could it be possible to identify the dominant tree species of a site by classifying its soil moisture pattern? To investigate this question we analyzed data from 15 sensor clusters in the lowlands of north-eastern Germany (within the TERENO observatory) which were instrumented with soil moisture sensors (5 profiles per site), tensiometers, sap flow sensors, throughfall and stemflow gages. Data has been collected at these sites since May 2014. While the summer data has already been analyzed, the analysis of the winter data and thus the possible seasonal shifts in patterns will be carried out in the coming months. Throughout the last summer we found different dynamics of soil moisture patterns under pine trees compared to beech trees. While the soils under beech trees were more often relatively wet and more often relatively dry, the soils under pine trees showed less variability and more often average soil moisture. These differences are most likely due to differences in both throughfall patterns as well as root water uptake. Further analysis includes the use of throughfall and stemflow data as well as stable water isotope samples that were taken at different depths in the soil, in the groundwater and from the sapwood. The manifestation of tree species differences in soil moisture patterns and dynamics is likely to have implications for groundwater recharge, transit times and hydrologic partitioning.

  3. Tree Age Effects on Fine Root Biomass and Morphology over Chronosequences of Fagus sylvatica, Quercus robur and Alnus glutinosa Stands.

    Science.gov (United States)

    Jagodzinski, Andrzej M; Ziółkowski, Jędrzej; Warnkowska, Aleksandra; Prais, Hubert

    2016-01-01

    There are few data on fine root biomass and morphology change in relation to stand age. Based on chronosequences for beech (9-140 years old), oak (11-140 years) and alder (4-76 years old) we aimed to examine how stand age affects fine root biomass and morphology. Soil cores from depths of 0-15 cm and 16-30 cm were used for the study. In contrast to previously published studies that suggested that maximum fine root biomass is reached at the canopy closure stage of stand development, we found almost linear increases of fine root biomass over stand age within the chronosequences. We did not observe any fine root biomass peak in the canopy closure stage. However, we found statistically significant increases of mean fine root biomass for the average individual tree in each chronosequence. Mean fine root biomass (0-30 cm) differed significantly among tree species chronosequences studied and was 4.32 Mg ha(-1), 3.71 Mg ha(-1) and 1.53 Mg ha(-1), for beech, oak and alder stands, respectively. The highest fine root length, surface area, volume and number of fine root tips (0-30 cm soil depth), expressed on a stand area basis, occurred in beech stands, with medium values for oak stands and the lowest for alder stands. In the alder chronosequence all these values increased with stand age, in the beech chronosequence they decreased and in the oak chronosequence they increased until ca. 50 year old stands and then reached steady-state. Our study has proved statistically significant negative relationships between stand age and specific root length (SRL) in 0-30 cm soil depth for beech and oak chronosequences. Mean SRLs for each chronosequence were not significantly different among species for either soil depth studied. The results of this study indicate high fine root plasticity. Although only limited datasets are currently available, these data have provided valuable insight into fine root biomass and morphology of beech, oak and alder stands.

  4. Comparative economic and environmental assessment of four beech wood based biorefinery concepts.

    Science.gov (United States)

    Budzinski, Maik; Nitzsche, Roy

    2016-09-01

    The aim of this study was to analyze four conceptual beech wood based biorefineries generated during process design in terms of environmental and economic criteria. Biorefinery 1 annually converts 400,000 dry metric tons of beech wood into the primary products 41,600t/yr polymer-grade ethylene and 58,520tDM/yr organosolv lignin and the fuels 90,800tDM/yr hydrolysis lignin and 38,400t/yr biomethane. Biorefinery 2 is extended by the product of 58,400t/yr liquid "food-grade" carbon dioxide. Biorefinery 3 produces 69,600t/yr anhydrous ethanol instead of ethylene. Compared to biorefinery 3, biorefinery 4 additionally provides carbon dioxide as product. Biorefinery 3 and 4 seem most promising, since under basic assumptions both criteria, (i) economic effectiveness and (ii) reduction of potential environmental impacts, can be fulfilled. All four alternatives may reduce potential environmental impacts compared to reference systems using the ReCiPe methodology. Economic feasibilities of the analyzed biorefineries are highly sensitive. PMID:27285577

  5. Plant biodiversity of beech forests in central-northern Italy: a methodological approach for conservation purposes

    Directory of Open Access Journals (Sweden)

    Marcantonio M

    2012-07-01

    Full Text Available Forests are reckoned essentials as biodiversity reservoirs and carbon sinks. Current threats to forest ecosystems (e.g., climate changes, habitat loss and fragmentation, management changes call for monitoring their biodiversity and preserving their ecological functions. In this study, we characterized plants diversity of five beech forests located in central and north Apennines mountain chain, using results by a probabilistic sampling. In order to achieve our goals, we have considered species richness and abundance, taxonomic distinctness and species composition, using both old and new analytical approaches. Results have shown how: (1 the forest type dominated by Fagus sylvatica is characterized by high complexity, with marked compositional, structural and biodiversity differences; (2 beech forests of Pigelleto di Piancastagnaio and Valle della Corte show the highest plants diversity values. The ecological characteristics of these areas, which sustain high diversity values, are unique and of great conservation interest; (3 the use of species richness as the only diversity measure have not allowed an efficient differentiation between studied areas. Indeed, the use of different indexes and analytical methods is required to detect multiple characteristics of biological diversity, as well as to carry out efficient biodiversity surveys aimed to develop optimal conservation strategies. In the future, we plan to apply the sampling methodology and the analytical approach used in this paper to characterize plants diversity of similar forest types.

  6. Fluxes of CO2, CH4 and N2O at two European beech forests: linking soil gas production profiles with soil and stem fluxes

    Science.gov (United States)

    Maier, Martin; Machacova, Katerina; Halaburt, Ellen; Haddad, Sally; Urban, Otmar; Lang, Friederike

    2016-04-01

    Soil and plant surfaces are known to exchange greenhouse gases with the atmosphere. Some gases like nitrous oxide (N2O) and methane (CH4) can be produced and re-consumed in different soil depths and soil compartments, so that elevated concentrations of CH4 or N2O in the soil do not necessarily mean a net efflux from the soil into the atmosphere. Soil aeration, and thus the oxygen status can underlay a large spatial variability within the soil on the plot and profile scale, but also within soil aggregates. Thus, conditions suitable for production and consumption of CH4 and N2O can vary on different scales in the soil. Plant surfaces can also emit or take up CH4 and N2O, and these fluxes can significantly contribute to the net ecosystem exchange. Since roots usually have large intercellular spaces or aerenchyma they may represent preferential transport ways for soil gases, linking possibly elevated soil gas concentrations in the subsoil in a "shortcut" to the atmosphere. We tested the hypothesis that the spatial variability of the soil-atmosphere fluxes of CO2, CH4 and N2O is caused by the heterogeneity in soil properties. Therefore, we measured soil-atmosphere gas fluxes, soil gas concentrations and soil diffusivity profiles and did a small scale field assessment of soil profiles on the measurments plots. We further tried to link vertical profiles of soil gas concentrations and diffusivity to derive the production and consumption profiles, and to link these profiles to the stem-atmosphere flux rates of individual trees. Measurements were conducted in two mountain beech forests with different geographical and climatic conditions (White Carpathians, Czech Republic; Black Forest, Germany). Gas fluxes at stem and soil levels were measured simultaneously using static chamber systems and chromatographic and continuous laser analyses. Monitoring simultaneously vertical soil gas profiles allowed to assess the within-soil gas fluxes, and thus to localize the production and

  7. Combining stable isotope and carbohydrate analyses in phloem sap and fine roots to study seasonal changes of source-sink relationships in a Mediterranean beech forest.

    Science.gov (United States)

    Scartazza, Andrea; Moscatello, Stefano; Matteucci, Giorgio; Battistelli, Alberto; Brugnoli, Enrico

    2015-08-01

    Carbon isotope composition (δ(13)C) and carbohydrate content of phloem sap and fine roots were measured in a Mediterranean beech (Fagus sylvatica L.) forest throughout the growing season to study seasonal changes of source-sink relationships. Seasonal variations of δ(13)C and content of phloem sap sugars, collected during the daylight period, reflected the changes in soil and plant water status. The correlation between δ(13)C and content of phloem sap sugars, collected from plants belonging to different social classes, was significantly positive only during the driest month of July. In this month, δ(13)C of phloem sap sugars was inversely related to the increment of trunk radial growth and positively related to δ(13)C of fine roots. We conclude that the relationship between δ(13)C and the amount of phloem sap sugars is affected by a combination of causes, such as sink strength, tree social class, changes in phloem anatomy and transport capacity, and phloem loading of sugars to restore sieve tube turgor following the reduced plant water potential under drought conditions. However, δ(13)C and sugar composition of fine roots suggested that phloem transport of leaf sucrose to this belowground component was not impaired by mild drought and that sucrose was in a large part allocated towards fine roots in July, depending on tree social class. Hence, fine roots could represent a functional carbon sink during the dry seasonal periods, when transport and use of assimilates in other sink tissues are reduced. These results indicate a strict link between above- and belowground processes and highlight a rapid response of this Mediterranean forest to changes in environmental drivers to regulate source-sink relationships and carbon sink capacity. PMID:26093372

  8. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

    Directory of Open Access Journals (Sweden)

    P. Priault

    2011-02-01

    Full Text Available Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objectives of our study were to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tunable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season, and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. Seasonal patterns of carbon allocation to soil CO2 efflux differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with other sinks (aboveground growth in late spring and storage in late summer that were not observed in oak.

  9. 77 FR 31642 - Hawker Beech Craft Defense Company, LLC, Also Known As Hawker Beechcraft Corporation, Also Known...

    Science.gov (United States)

    2012-05-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration Hawker Beech Craft Defense Company, LLC, Also Known As Hawker Beechcraft Corporation, Also Known As Hawker Beechcraft International SVC, Also Known As Rapid Surplus...

  10. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda;

    2002-01-01

    treatment gave a more reactive surface than alkaline wet oxidation for wheat straw, whereas the opposite was observed for beech. Fourier transform infrared (FT-IR) spectroscopy showed an almost complete loss of the ester carbonyl stretching signal and the corresponding C-C-O stretching in wet...

  11. The influece of forest gaps on some properties of humus in a managed beech forest, northern Iran

    Science.gov (United States)

    Vajari, K. A.

    2015-10-01

    The present research focuses on the effect of eight-year-old artificially created gaps on some properties of humus in managed beech-dominated stand in Hyrcanian forest of northern Iran. In this study, six-teen gaps were sampled in site and were classified into four classes (small, medium, large, and very large) with four replications for each. Humus sampling was carried out at the centre and at the cardinal points within each gap as well as in the adjacent closed stand, separately, as composite samples. The variables of organic carbon, P, K, pH, and total N were measured for each sample. It was found that the gap size had significant effect only on total N (%) and organic carbon (%) in beech stand. The amount of potassium clearly differed among three positions in beech forest. The adjacent stand had higher significantly potassium than center and edge of gaps. Different amount of potassium was detected in gap center and gap edge. Comparison of humus properties between gaps and its adjacent stand pointed to the higher amount of potassium in adjacent stand than that in gaps but there was no difference between them regarding other humus properties. According to the results, it can be concluded that there is relatively similar condition among gaps and closed adjacent stands in terms of humus properties eight years after logging in the beech stand.

  12. Climate change impairs processes of soil and plant N cycling in European beech forests on marginal soil

    Science.gov (United States)

    Tejedor, Javier; Gasche, Rainer; Gschwendtner, Silvia; Leberecht, Martin; Bimüller, Carolin; Kögel-Knabner, Ingrid; Pole, Andrea; Schloter, Michael; Rennenberg, Heinz; Simon, Judy; Hanewinkel, Marc; Baltensweiler, Andri; Bilela, Silvija; Dannenmann, Michael

    2014-05-01

    Beech forests of Central Europe are covering large areas with marginal calcareous soils, but provide important ecological services and represent a significant economical value. The vulnerability of these ecosystems to projected climate conditions (higher temperatures, increase of extreme drought and precipitation events) is currently unclear. Here we present comprehensive data on the influence of climate change conditions on ecosystem performance, considering soil nitrogen biogeochemistry, soil microbiology, mycorrhiza ecology and plant physiology. We simultaneously quantified major plant and soil gross N turnover processes by homogenous triple 15N isotope labeling of intact beech natural regeneration-soil-microbe systems. This isotope approach was combined with a space for time climate change experiment, i.e. we transferred intact beech seedling-soil-microbe mesocosms from a slope with N-exposure (representing present day climate conditions) to a slope with S exposure (serving as a warmer and drier model climate for future conditions). Transfers within N slope served as controls. After an equilibration period of 1 year, three isotope labeling/harvest cycles were performed. Reduced soil water content resulted in a persistent decline of ammonia oxidizing bacteria in soil (AOB). Consequently, we found a massive five-fold reduction of gross nitrification in the climate change treatment and a subsequent strong decline in soil nitrate concentrations as well as nitrate uptake by microorganisms and beech. Because nitrate was the major nutrient for beech in this forest type with little importance of ammonium and amino acids, this resulted in a strongly reduced performance of beech natural regeneration with reduced N content, N metabolite concentrations and plant biomass. These findings provided an explanation for a large-scale decline of distribution of beech forests on calcareous soils in Europe by almost 80% until 2080 predicted by statistical modeling. Hence, we

  13. Regulation of N2O and NOx emission patterns in six acid temperate beech forest soils by soil gas diffusivity, N turnover, and atmospheric NOx concentrations

    OpenAIRE

    Eickenscheidt, Nadine; Brumme, Rainer

    2013-01-01

    Low gas diffusivity of the litter layer is held responsible for high seasonal nitrous oxide (N2O) and low nitric oxide (NO) emissions from acid beech forest soils with moder type humus. The objectives were (i) to evaluate whether these beech forest soils generally exhibit high seasonal N2O emissions and (ii) to assess the influence of gas diffusivity and nitrogen (N) mineralisation on N oxide fluxes.We measured N2O and NOx (NO + NO2) fluxes in six German beech stands and determined net N turn...

  14. Effects of increased UV-B radiation and elevated levels of tropospheric ozone on physiological processes in European beech (Fagus sylvatica)

    International Nuclear Information System (INIS)

    As a consequence of the ongoing reduction of the stratospheric ozone layer, the vegetation is exposed to increasing levels of UV-B radiation (280–320 nm). In addition ozone in the troposphere is a pollutant and also capable of affecting the photosynthetic machinery. In this study, 5-year-old European beech trees were exposed from 1 July to October 1993 to two levels of UV-B radiation and two levels of ozone, alone and in combination, in open-top chambers equipped with lamps. The simulated UV-B levels corresponded to either clear sky ambient level or a 14% decrease in the stratospheric ozone column over eastern Denmark, resulting in a 23% difference in biologically effective UV-B (UV-BBE) irradiance. The maximum UV-BBE given was 8.61 kJ m−2 day−1. The ozone levels were either the ambient (average 32 nl l−1) or ambient with ozone addition (average resulting concentration 71 nl l−1). Compared to the control treatment (ambient UV-B, ambient O3) the elevated levels of UV-B and O3 affected the trees negatively, expressed as declines in net photosynthesis (Pn), stomatal conductance (gs), chlorophyll fluorescence (Fv/Fm) and acceleration of senescence, measured as yellowing of the leaves. The UV-B treatment induced stomatal closure before the other treatments did. The magnitude of the decreases in Pn and Fv/Fm occurred in the order: control trees in the chambers showed a higher Pn and Fv/Fm and a 14-day delayed senescence compared to the trees outside

  15. Profile distribution and temporal changes of sulphate and nitrate contents and related soil properties under beech and spruce forests.

    Science.gov (United States)

    Tejnecký, Václav; Bradová, Monika; Borůvka, Luboš; Němeček, Karel; Sebek, Ondřej; Nikodem, Antonín; Zenáhlíková, Jitka; Rejzek, Jan; Drábek, Ondřej

    2013-01-01

    The behaviour of principal inorganic anions in forest soils, originating mainly from acid deposition, strongly influences the forest ecosystem response on acidification. The aim of this study was to describe seasonal and temporal changes of sulphate and nitrate contents and related soil properties under beech and spruce forests in a region heavily impacted by acidification. The Jizera Mountains area (Czech Republic) was chosen as such a representative mountainous soil ecosystem. Soil samples were collected at monthly intervals from April to October during the years 2008-2010 under both beech and spruce stands. Soil samples were collected from surface fermentation (F) and humified (H) organic horizons, humic (A) organo-mineral horizons and subsurface mineral (B) horizons (cambic or spodic). A deionised water extract was applied to unsieved fresh samples and the content of anions in these extracts was determined by ion chromatography (IC). In the studied soil profiles, the lowest amount of SO(4)(2-) was found in the organo-mineral A horizons under both types of vegetation. Under spruce the highest amount of SO(4)(2-) was determined in mineral spodic (B) horizons, where a strong sorption influence of Fe and Al oxy-hydroxides is expected. Under beech the highest amount was observed in the surface organic F horizons (forest floor). The amount of NO(3)(-) is highest in the F horizons and decreases with increasing soil profile depth under both types of vegetation. A significantly higher amount of NO(3)(-) was determined in soils under the beech stand compared to spruce. For both soil environments - under beech and also spruce stands - we have determined a general increase of water-extractable SO(4)(2-) and NO(3)(-) during the whole monitoring period. The behaviour of SO(4)(2-) and NO(3)(-) in the soils is strongly related to the dynamics of soil organic matter and particularly to the DOC.

  16. Finite Sholander Trees, Trees, and their Betweenness

    CERN Document Server

    Chvátal, Vašek; Schäfer, Philipp Matthias

    2011-01-01

    We provide a proof of Sholander's claim (Trees, lattices, order, and betweenness, Proc. Amer. Math. Soc. 3, 369-381 (1952)) concerning the representability of collections of so-called segments by trees, which yields a characterization of the interval function of a tree. Furthermore, we streamline Burigana's characterization (Tree representations of betweenness relations defined by intersection and inclusion, Mathematics and Social Sciences 185, 5-36 (2009)) of tree betweenness and provide a relatively short proof.

  17. Recovery of trees from drought depends on belowground sink control.

    Science.gov (United States)

    Hagedorn, Frank; Joseph, Jobin; Peter, Martina; Luster, Jörg; Pritsch, Karin; Geppert, Uwe; Kerner, Rene; Molinier, Virginie; Egli, Simon; Schaub, Marcus; Liu, Jian-Feng; Li, Maihe; Sever, Krunoslav; Weiler, Markus; Siegwolf, Rolf T W; Gessler, Arthur; Arend, Matthias

    2016-01-01

    Climate projections predict higher precipitation variability with more frequent dry extremes(1). CO2 assimilation of forests decreases during drought, either by stomatal closure(2) or by direct environmental control of sink tissue activities(3). Ultimately, drought effects on forests depend on the ability of forests to recover, but the mechanisms controlling ecosystem resilience are uncertain(4). Here, we have investigated the effects of drought and drought release on the carbon balances in beech trees by combining CO2 flux measurements, metabolomics and (13)CO2 pulse labelling. During drought, net photosynthesis (AN), soil respiration (RS) and the allocation of recent assimilates below ground were reduced. Carbohydrates accumulated in metabolically resting roots but not in leaves, indicating sink control of the tree carbon balance. After drought release, RS recovered faster than AN and CO2 fluxes exceeded those in continuously watered trees for months. This stimulation was related to greater assimilate allocation to and metabolization in the rhizosphere. These findings show that trees prioritize the investment of assimilates below ground, probably to regain root functions after drought. We propose that root restoration plays a key role in ecosystem resilience to drought, in that the increased sink activity controls the recovery of carbon balances. PMID:27428669

  18. Impact of the 2013-2015 weather variability on seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species

    Science.gov (United States)

    van der Maaten, Ernst; Pape, Jonas; van der Maaten Theunissen, Marieke; Scharnweber, Tobias; Smiljanic, Marko; Wilmking, Martin

    2016-04-01

    Dendrometers are measurement devices that continuously monitor stem-size changes of trees without invasive sampling of the cambium. Dendrometers record both irreversible tree growth as well as reversible signals of stem water storage and depletion, making them important tools for studying tree water status, tree physiology and short-term growth responses of trees to weather fluctuations. In this study, a three-year dendrometer dataset (2013-2015) is used to study seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species (common hornbeam (Carpinus betulus L.), European beech (Fagus sylvatica L.), and pedunculate oak (Quercus robur L.)), growing in an unmanaged forest in northeastern Germany. Seasonal growth patterns (i.e. growth onset, cessation and duration) are analyzed in relation to environmental conditions, and forest meteorological factors driving daily stem-size changes are identified. Following dry conditions in 2014, especially the growth of beech was reduced. Oak was less affected, and displayed a distinct early growth onset for all study years.

  19. URBAN TREE CLASSIFICATION USING FULL-WAVEFORM AIRBORNE LASER SCANNING

    Directory of Open Access Journals (Sweden)

    Zs. Koma

    2016-06-01

    Full Text Available Vegetation mapping in urban environments plays an important role in biological research and urban management. Airborne laser scanning provides detailed 3D geodata, which allows to classify single trees into different taxa. Until now, research dealing with tree classification focused on forest environments. This study investigates the object-based classification of urban trees at taxonomic family level, using full-waveform airborne laser scanning data captured in the city centre of Vienna (Austria. The data set is characterised by a variety of taxa, including deciduous trees (beeches, mallows, plane trees and soapberries and the coniferous pine species. A workflow for tree object classification is presented using geometric and radiometric features. The derived features are related to point density, crown shape and radiometric characteristics. For the derivation of crown features, a prior detection of the crown base is performed. The effects of interfering objects (e.g. fences and cars which are typical in urban areas on the feature characteristics and the subsequent classification accuracy are investigated. The applicability of the features is evaluated by Random Forest classification and exploratory analysis. The most reliable classification is achieved by using the combination of geometric and radiometric features, resulting in 87.5% overall accuracy. By using radiometric features only, a reliable classification with accuracy of 86.3% can be achieved. The influence of interfering objects on feature characteristics is identified, in particular for the radiometric features. The results indicate the potential of using radiometric features in urban tree classification and show its limitations due to anthropogenic influences at the same time.

  20. Urban Tree Classification Using Full-Waveform Airborne Laser Scanning

    Science.gov (United States)

    Koma, Zs.; Koenig, K.; Höfle, B.

    2016-06-01

    Vegetation mapping in urban environments plays an important role in biological research and urban management. Airborne laser scanning provides detailed 3D geodata, which allows to classify single trees into different taxa. Until now, research dealing with tree classification focused on forest environments. This study investigates the object-based classification of urban trees at taxonomic family level, using full-waveform airborne laser scanning data captured in the city centre of Vienna (Austria). The data set is characterised by a variety of taxa, including deciduous trees (beeches, mallows, plane trees and soapberries) and the coniferous pine species. A workflow for tree object classification is presented using geometric and radiometric features. The derived features are related to point density, crown shape and radiometric characteristics. For the derivation of crown features, a prior detection of the crown base is performed. The effects of interfering objects (e.g. fences and cars which are typical in urban areas) on the feature characteristics and the subsequent classification accuracy are investigated. The applicability of the features is evaluated by Random Forest classification and exploratory analysis. The most reliable classification is achieved by using the combination of geometric and radiometric features, resulting in 87.5% overall accuracy. By using radiometric features only, a reliable classification with accuracy of 86.3% can be achieved. The influence of interfering objects on feature characteristics is identified, in particular for the radiometric features. The results indicate the potential of using radiometric features in urban tree classification and show its limitations due to anthropogenic influences at the same time.

  1. Comparative study on the mechanical performance of beech and ash laminated panels

    Directory of Open Access Journals (Sweden)

    Andreea HEGYI

    2014-07-01

    Full Text Available This paper presents a comparative study on the mechanical performance of beech and ash wood laminated panels. Within the experimental study the bending strength, bending modulus of elasticity and the bonding characteristics to gluing (bonding quality were analyzed. The experimental results emphasized the influence of the type of wood, the panel thickness, the effect on the bending strength, respectively on the gluing quality of the direction of the wood lamellas in relation with the mechanical load (direction of cutting specimens. It can be said that the use of hardwood meets the needs and demands of the construction area, but it’s necessary a careful analysis of the requests that occur mainly at the site, thus an optimal direction of the wooden glued lamellas can be chosen. Laminated wood panels are a product with real physical and mechanical qualities, which can be successfully used to obtain construction elements that are bringing benefits to environmental quality of living areas.

  2. Characteristics of the soil in mountain beech communities on mountain Manjača

    Directory of Open Access Journals (Sweden)

    Eremija Saša

    2008-01-01

    Full Text Available The presented results of soil study, which will be used for defining the beech forest types of management unit 'Dubička Gora' on Mt. Manjača, are the basis for solving a series of current tasks of forestry profession. Relief and chemical nature of limestone are the main factors of the soil cover differentiation (Knežević, Košanin, 2004.. The results of physical and chemical soil properties are shown and its taxonomy is determined. Forest cover is represented by heterogeneous units-forest combinations. Four basic soil types are defined on the basis of detailed field and laboratory research: rendzina on dolomite, chernozem on limestone, brown soil on limestone, illimerised soil on limestone and dolomite.

  3. Black carbon surface oxidation and organic composition of beech-wood soot aerosols

    Directory of Open Access Journals (Sweden)

    J. C. Corbin

    2015-10-01

    oxygenated carbonaceous ions (CO1-2+, potassium (K+, and water (H2O+ and related fragments. The C4+ : C3+ ratio, but not the C1+ : C3+ ratio, was consistent with the BC-structure trends of Corbin et al. (2015c. The CO1-2+ signals likely originated from BC surface groups: upon aging, both CO+ and CO2+ increased relative to C1-3+ while CO2+ simultaneously increased relative to CO+. Factor analysis (positive matrix factorization of SP-AMS and AMS data, using a modified error model to address peak-integration uncertainties, indicated that the surface composition of the BC was approximately constant across all stages of combustion for both fresh and aged samples. These results represent the first time-resolved measurements of in situ BC surface aging and suggest that the surface of beech-wood BC may be modelled as a single chemical species.

  4. The influence of seedling density in containers on morphological characteristics of European beech

    Directory of Open Access Journals (Sweden)

    Wrzesiński Piotr

    2015-09-01

    Full Text Available This study examines the influence on growth parameters, in particular the morphological features of the root system, of 1-year-old European beech seedlings cultivated in containers with two different densities. The experiment was conducted in the container nursery in Skierdy (Forest District of Jabłonna in spring 2011. After 10 months of cultivation in Hiko polyethylene containers, above- and below-ground parts of the seedlings were measured. The measurements of the root system were conducted with a scanner and the WinRHIZO software. No influence due to the seedling density on either shoot height or thickness was observed, but instead the research showed that different seedling densities affected the development of root systems. The mean root thickness and dry mass of the European beech seedlings were significantly higher at the lower density. The influence of seedling density on the development of root mass deserves special attention as it is the most important factor affecting future growth of the seedlings during cultivation. This tendency also suggests that the amount of nutrients allocated to shoot development may be higher in order to improve the efficiency of photosynthesis. At both densities, differences in biomass accumulation affected the root-toshoot ratio. In seedlings cultivated at the lower density, the increased dry root matter of the seedlings resulted in a significant increase in the root-to-shoot ratio. This may cause a potential growth advantage of these seedlings after they are planted and may thus result in a more productive cultivation.

  5. Methanol and other VOC fluxes from a Danish beech forest during springtime

    Directory of Open Access Journals (Sweden)

    G. W. Schade

    2008-11-01

    Full Text Available In-canopy mixing ratio gradients and above-canopy fluxes of several volatile organic compounds (VOCs were measured using a commercial proton transfer reaction mass spectrometer (PTR-MS in a European beech (Fagus sylvatica forest in Denmark. Emission fluxes of methanol occurred dominantly late at night, which was supported by highest mixing ratios in the crown region, and is in line with recent controlled laboratory experiments. Also confirming previous measurements, monoterpene emissions showed a diurnal cycle consistent with light-dependent emissions, supported by highest mixing ratios in the canopy space during early afternoon. Also emitted was acetone, but only at ambient temperatures exceeding 20°C. Deposition dominated at lower temperatures. Deposition fluxes occurred also for methanol but seemingly as a result of high ambient methanol mixing ratios. Our in-canopy gradient measurements contrasted earlier results from tropical and pine forest ecosystems in that they did not show this beech ecosystem to be a strong sink for oxygenated VOCs. Instead, their gradients were flat and only small deposition velocities (<0.1 cm s–1 were observed to the onsite soil. However, as soil uptake was consistent and appeared to be related to soil moisture, more measurements are needed to evaluate the soil sink strength. In turn, as canopy scale fluxes are net fluxes with emissions from photosynthesizing leaves affecting potential oxygenated VOC uptake, only independent, controlled laboratory experiments may be successful in separating stomatal from non-stomatal fluxes, and emission from deposition.

  6. Modular Tree Automata

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2012-01-01

    Tree automata are traditionally used to study properties of tree languages and tree transformations. In this paper, we consider tree automata as the basis for modular and extensible recursion schemes. We show, using well-known techniques, how to derive from standard tree automata highly modular r...

  7. Identifying Standing Dead Trees in Forest Areas Based on 3d Single Tree Detection from Full Waveform LIDAR Data

    Science.gov (United States)

    Yao, W.; Krzystek, P.; Heurich, M.

    2012-07-01

    In forest ecology, a snag refers to a standing, partly or completely dead tree, often missing a top or most of the smaller branches. The accurate estimation of live and dead biomass in forested ecosystems is important for studies of carbon dynamics, biodiversity, and forest management. Therefore, an understanding of its availability and spatial distribution is required. So far, LiDAR remote sensing has been successfully used to assess live trees and their biomass, but studies focusing on dead trees are rare. The paper develops a methodology for retrieving individual dead trees in a mixed mountain forest using features that are derived from small-footprint airborne full waveform LIDAR data. First, 3D coordinates of the laser beam reflections, the pulse intensity and width are extracted by waveform decomposition. Secondly, 3D single trees are detected by an integrated approach, which delineates both dominate tree crowns and understory small trees in the canopy height model (CHM) using the watershed algorithm followed by applying normalized cuts segmentation to merged watershed areas. Thus, single trees can be obtained as 3D point segments associated with waveform-specific features per point. Furthermore, the tree segments are delivered to feature definition process to derive geometric and reflectional features at single tree level, e.g. volume and maximal diameter of crown, mean intensity, gap fraction, etc. Finally, the spanned feature space for the tree segments is forwarded to a binary classifier using support vector machine (SVM) in order to discriminate dead trees from the living ones. The methodology is applied to datasets that have been captured with the Riegl LMSQ560 laser scanner at a point density of 25 points/m2 in the Bavarian Forest National Park, Germany, respectively under leaf-on and leaf-off conditions for Norway spruces, European beeches and Sycamore maples. The classification experiments lead in the best case to an overall accuracy of 73% in a leaf

  8. Forest trees filter chronic wind-signals to acclimate to high winds.

    Science.gov (United States)

    Bonnesoeur, Vivien; Constant, Thiéry; Moulia, Bruno; Fournier, Meriem

    2016-05-01

    Controlled experiments have shown that trees acclimate thigmomorphogenetically to wind-loads by sensing their deformation (strain). However, the strain regime in nature is exposed to a full spectrum of winds. We hypothesized that trees avoid overreacting by responding only to winds which bring information on local climate and/or wind exposure. Additionally, competition for light dependent on tree social status also likely affects thigmomorphogenesis. We monitored and manipulated quantitatively the strain regimes of 15 pairs of beech (Fagus sylvatica) trees of contrasting social status in an acclimated stand, and quantified the effects of these regimes on the radial growth over a vegetative season. Trees exposed to artificial bending, the intensity of which corresponds to the strongest wind-induced strains, enhanced their secondary growth by at least 80%. Surprisingly, this reaction was even greater - relatively - for suppressed trees than for dominant ones. Acclimated trees did not sense the different types of wind events in the same way. Daily wind speed peaks due to thermal winds were filtered out. Thigmomorphogenesis was therefore driven by intense storms. Thigmomorphogenesis is also likely to be involved in determining social status.

  9. Bronchi, Bronchial Tree, & Lungs

    Science.gov (United States)

    ... specific Modules Resources Archived Modules Updates Bronchi, Bronchial Tree, & Lungs Bronchi and Bronchial Tree In the mediastinum , at the level of the ... trachea. As the branching continues through the bronchial tree, the amount of hyaline cartilage in the walls ...

  10. INDUSTRIAL SCALE BEECH WOODLAM GST AND FINGERJOINTS BY MAXIMIZING NATURAL COMPONENTS IN HONEYMOON FAST-SET ADHESIVES

    Directory of Open Access Journals (Sweden)

    Pierre-Jean MÉAUSOONE

    2014-12-01

    Full Text Available Fingerjoints and woodlam GST (Glued Laminated Timber were prepared with beech wood on industrial scale with a cold-set honeymoon type adhesive comprising 65% of natural material, namely condensed flavonoid tannin, already developed to satisfy the relevant adhesives standard requirements. The adhesive system stood up to the scaling up to industrial dimension with good performance of strength. The strength characteristic were compared with those obtained with a 50% natural material honeymoon adhesive already in commercial operation for several decades with yielding even better results. Full scale fingerjoints and woodlam prepared with beech timber gave good results. The fast-set characteristics of the adhesive system were maintained in the scaling up too.

  11. Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates in northwestern Turkey

    Directory of Open Access Journals (Sweden)

    Sariyildiz T

    2016-02-01

    Full Text Available Effects of tree species, stand age and land-use change on soil carbon and nitrogen stock rates were investigated in the northwest of Turkey using 4 common tree species as black pine (Pinus nigra Arnold., Scots pine (Pinus sylvestris L., Oriental beech (Fagus orientalis Lipsky and Uludag fir (Abies nordmanniana ssp. bornmuelleriana. Three tree species (black pine, Scots pine and Oriental beech were used to investigate the differences in soil C and N among tree species. Old and young Uludag fir stands and adjacent grassland were used to study the differences in soil C and N with stand age and land-use change. Mineral soil samples were taken from 0-10 cm and 10-20 cm soil depths, and analyzed for pH, soil texture, bulk density, total soil carbon and total nitrogen. The total soil carbon and total nitrogen pools were then calculated by multiplying soil volume, soil bulk density, and the total soil carbon or total nitrogen content. Results showed significant differences in soil carbon and nitrogen contents, carbon/nitrogen ratios and stock rates among the three species, and between old and young fir stands and grassland. In general, when 0-20 cm soil depth was considered, mean soil carbon stock rate was the highest under black pine (79 Mg C ha-1 followed by Scots pine (73 Mg C ha-1 and beech (67 Mg C ha-1, whereas mean soil nitrogen stock rate was the highest under beech (9.57 Mg N ha-1 followed by Scots pine (5.77 Mg N ha-1 and black pine (4.20 Mg N ha-1. Young fir stands showed lower soil carbon stock, but higher soil nitrogen stock rates compared to old fir stands and grassland. Our results demonstrated that tree species, stand tree age and land-use change can have significant effects on soil carbon and nitrogen content and stocks rates. These findings can help to enhance forest management activities, such as selection of tree species for carbon sequestration in plantation systems, design of sustainable agroforestry systems, and improvement of

  12. Girdling Affects Ectomycorrhizal Fungal (EMF) Diversity and Reveals Functional Differences in EMF Community Composition in a Beech Forest

    OpenAIRE

    Pena, R.; Offermann, C.; Simon, J.; Naumann, P. S.; Gessler, A.; Holst, J; Dannenmann, M.; Mayer, H.; Kogel-Knabner, I.; Rennenberg, H.; Polle, A.

    2010-01-01

    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...

  13. Response of ectomycorrhizal community structure to gap opening in natural and managed temperate beech-dominated forests

    OpenAIRE

    Grebenc, Tine; Christensen, Morten; Vilhar, Urša; Čater, Matjaž; Martín, María P.; Simončič, Primož; Kraigher, Hojka

    2009-01-01

    Data on the impact of forest management practices on ectomycorrhizal community structure remains fragmentary and mainly originates from studies in northern coniferous forests. This study focuses on a comparison of ectomycorrhizal communities between canopy gaps and closed canopy areas within natural and managed beech-dominated forests at four locations in Europe. We used high resolution rDNA techniques to identify ectomycorrhiza-forming fungi and attempted to extract potential stand-, gap-, s...

  14. Variability of half-sib progeny properties as the base of Moesian beech (Fagus moesiaca (Maly) Czeczott) breeding

    OpenAIRE

    Ocokoljić Mirjana; Anastasijević Nebojša

    2004-01-01

    Based on the analysis of several morphological features and phenotype characteristics of seedlings in the juvenile test with 10 half-sib lines of Moesian beech (Fagus moesiaca (Maly) Czeczott), this paper gives the guidelines for further breeding and production of planting material for urban coenoses and the establishment of special purpose plantations of this species. The comparative analysis enabled the identification of the extreme planting material for further breeding programs aiming at ...

  15. An interactive effect of simultaneous death of dwarf bamboo, canopy gap, and predatory rodents on beech regeneration.

    Science.gov (United States)

    Abe, M; Miguchi, H; Nakashizuka, T

    2001-04-01

    To clarify the interactive effect of the simultaneous death of dwarf bamboo (Sasa kurilensis), forest canopy gap formation, and seed predators on beech (Fagus crenata) regeneration, we analyzed beech demography from seed fall until the end of the first growing season of seedlings in an old-growth forest near Lake Towada, northern Japan. The simultaneous death of S. kurilensis took place in 1995. We established four types of sampling site differing in forest canopy conditions (closed or gap) and Sasa status (dead or alive). Beech seed survival and emergence ratio were both highest in gaps with dead Sasa (gap-dead), because rate of predation was lowest. Seedling survival during the first growing season was also highest in the gap-dead treatment, because of less predation and less damping off. As a result, even though density of seed fall was lowest in the gap-dead treatment, the living seedling density there was highest at the end of the first growing season. Predation, which caused the greatest mortality during the seed and seedling stages, was significantly lower at both sites in gaps and sites with dead Sasa. This was probably due to changes in the behavior of rodents in response to the structure of the forest canopy and undergrowth. Both the death of Sasa and canopy gap formation allowed seedlings to avoid damping off because of the high light availability. The indirect effect of the simultaneous death of Sasa and canopy gap formation in reducing predation contributed more to beech regeneration than their direct effect in increasing light for the seedlings. PMID:24577661

  16. Stomatal and non-stomatal limitations on leaf carbon assimilation in beech (Fagus sylvatica L.) seedlings under natural conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, I.; Rodriguez-Calcerrada, J.; Robson, T. M.; Cano, F. J.; Alte, L.; Sanchez-Gomez, D.

    2012-07-01

    Limitations to diffusion and biochemical factors affecting leaf carbon uptake were analyzed in young beech seedlings (Fagus sylvtica L.) growing in natural gaps of a beech-wood at the southern limit of the species. Half of the seedlings received periodic watering in addition to natural rainfall to reduce the severity of the summer drought. Plant water status was evaluated by measuring predawn water potential. Basic biochemical parameters were inferred from chlorophyll fluorescence and photosynthesis-CO{sub 2} curves (A-C{sub c}) under saturating light. The curves were established on three dates during the summer months. The main variables studied included: stomatal and mesophyll conductance to CO{sub 2} (g{sub s} and g{sub m} respectively), maximum velocity of carboxylation (V{sub c}max) and maximum electron transport capacity (J{sub m}ax). The gm was estimated by two methodologies: the curve-fitting and J constant methods. Seedlings withstood moderate water stress, as the leaf predawn water potential ({Psi}{sub p}d) measured during the study was within the range -0.2 to -0.5 MPa. Mild drought caused gs and gm to decrease only slightly in response to {Psi}{sub p}d. However both diffusional parameters explained most of the limitations to CO{sub 2} uptake. In addition, it should be highlighted that biochemical limitations, prompted by V{sub c}max and J{sub m}ax, were related mainly to ontogenic factors, without any clear relationship with drought under the moderate water stress experienced by beech seedlings through the study. The results may help to further understanding of the functional mechanisms influencing the carbon fixation capacity of beech seedlings under natural conditions. (Author) 68 refs.

  17. Seasonal variations of belowground carbon transfer assessed by in situ 13CO2 pulse labelling of trees

    Directory of Open Access Journals (Sweden)

    L. Barthes

    2011-05-01

    Full Text Available Soil CO2 efflux is the main source of CO2 from forest ecosystems and it is tightly coupled to the transfer of recent photosynthetic assimilates belowground and their metabolism in roots, mycorrhiza and rhizosphere microorganisms feeding on root-derived exudates. The objective of our study was to assess patterns of belowground carbon allocation among tree species and along seasons. Pure 13CO2 pulse labelling of the entire crown of three different tree species (beech, oak and pine was carried out at distinct phenological stages. Excess 13C in soil CO2 efflux was tracked using tuneable diode laser absorption spectrometry to determine time lags between the start of the labelling and the appearance of 13C in soil CO2 efflux and the amount of 13C allocated to soil CO2 efflux. Isotope composition (δ13C of CO2 respired by fine roots and soil microbes was measured at several occasions after labelling, together with δ13C of bulk root tissue and microbial carbon. Time lags ranged from 0.5 to 1.3 days in beech and oak and were longer in pine (1.6–2.7 days during the active growing season, more than 4 days during the resting season, and the transfer of C to the microbial biomass was as fast as to the fine roots. The amount of 13C allocated to soil CO2 efflux was estimated from a compartment model. It varied between 1 and 21 % of the amount of 13CO2 taken up by the crown, depending on the species and the season. While rainfall exclusion that moderately decreased soil water content did not affect the pattern of carbon allocation to soil CO2 efflux in beech, seasonal patterns of carbon allocation belowground differed markedly between species, with pronounced seasonal variations in pine and beech. In beech, it may reflect competition with the strength of other sinks (aboveground growth in late spring and storage in late summer that were not observed in oak. We report a fast transfer of recent photosynthates to the mycorhizosphere and we conclude that the

  18. Tree Tectonics

    Science.gov (United States)

    Vogt, Peter R.

    2004-09-01

    Nature often replicates her processes at different scales of space and time in differing media. Here a tree-trunk cross section I am preparing for a dendrochronological display at the Battle Creek Cypress Swamp Nature Sanctuary (Calvert County, Maryland) dried and cracked in a way that replicates practically all the planform features found along the Mid-Oceanic Ridge (see Figure 1). The left-lateral offset of saw marks, contrasting with the right-lateral ``rift'' offset, even illustrates the distinction between transcurrent (strike-slip) and transform faults, the latter only recognized as a geologic feature, by J. Tuzo Wilson, in 1965. However, wood cracking is but one of many examples of natural processes that replicate one or several elements of lithospheric plate tectonics. Many of these examples occur in everyday venues and thus make great teaching aids, ``teachable'' from primary school to university levels. Plate tectonics, the dominant process of Earth geology, also occurs in miniature on the surface of some lava lakes, and as ``ice plate tectonics'' on our frozen seas and lakes. Ice tectonics also happens at larger spatial and temporal scales on the Jovian moons Europa and perhaps Ganymede. Tabletop plate tectonics, in which a molten-paraffin ``asthenosphere'' is surfaced by a skin of congealing wax ``plates,'' first replicated Mid-Oceanic Ridge type seafloor spreading more than three decades ago. A seismologist (J. Brune, personal communication, 2004) discovered wax plate tectonics by casually and serendipitously pulling a stick across a container of molten wax his wife and daughters had used in making candles. Brune and his student D. Oldenburg followed up and mirabile dictu published the results in Science (178, 301-304).

  19. Chemical Elements in Mulch and Litterfall of Beech Ecosystems and Their Total Turnover

    Directory of Open Access Journals (Sweden)

    Mariyana I. Lyubenovа

    2011-07-01

    Full Text Available The beech communities on the territory of Bulgaria had been objects of regional, local as well as large scale national investigations aiming their classification, determination of their ecological characteristics, conservation status, habitats etc. They are included as objects of the intensive monitoring of forest ecosystems in Bulgaria also. The investigations of chemical content of the litter – fall in these forests were conducted until now. The novelty of the present research is investigation of these elements in the mulch and the ratio between the established quantities calculation. The main goal is the biological turnover special features characterization of the investigated elements which give us a chance to define the investigated ecosystems state and functioning. The indexes as litter – mulch and acropetal coefficients were used for this aim. The content of macroelements as N, Ca and K and microelements as Pb, Zn, Mn and Fe in soils, mulch and in different litter fall fractions have been calculated. The investigation was carried out on three sample plots. During the investigation was established that the soils are characterized with acid reaction, high content of Fe, N and Mn and low content of Ca and K. The concentration of Zn and Pb are high also. The calculated average store of investigated elements in litter – fall is 81.312 kg.ha1 and in the mulch 314 kg.ha1. According to the acropetal coefficient N is accumulated mainly in the acorns, K – in the annual phytomass fractions and Ca – in the perennial fractions. The leaves and the acorns fraction accumulate Mn, and cupolas Fe. The litter – mulch coefficient vary from 1,6 (Mn to 4,2 (Pb. The tendencies of Zn and Ca turnovers acceleration are discovered, while the turnover of more investigated elements is inhibited. The litter – mulch coefficient for Zn and Ca is 0,8 and 1,4 accordingly, i.е. corresponding to the intensive type of turnovers which is not typical for the

  20. Healthy,Happy trees

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Healthy trees are important to us all. Trees provide shade, beauty, and homes for wildlife. Trees give us products like paper and wood. Trees can give us all this only if they are healthy.They must be well cared for to remain healthy.

  1. Dissolution of granulated wood ash examined by in situ incubation: Effects of tree species and soil type

    DEFF Research Database (Denmark)

    Callesen, Ingeborg; Ingerslev, M.; Raulund-Rasmussen, K.

    2007-01-01

    handling and to avoid undesired effects on vegetation and leaching of nutrients. Forest ecosystems with different tree species and soils provide variable conditions for mineral dissolution with respect to pH, amount of organic ligands and humidity in the forest floor and the top soil. To study the effects...... of tree species and soil type on wood ash dissolution, granulated wood ash with particle size 2-4 mm was incubated in situ for 7 years in polyamide mesh bags. The bags were placed under the organic horizon of beech, oak, Norway spruce and Douglas-fir on a nutrient poor soil (typic Haplorthod......) and a nutrient-rich soil (oxyaquic Hapludalf) in Denmark. After 7 years of incubation, the weight loss of the wood ash granulates was 20% in both soil types. Nutrient losses determined by total element analysis were about 35% for calcium, magnesium and potassium and 19% for phosphorus, regardless of tree species...

  2. X-tree

    OpenAIRE

    Keim, Daniel A.; Bustos Cárdenas, Benjamin Eugenio; Berchtold, Stefan; Kriegel, Hans-Peter

    2008-01-01

    The X-tree (eXtended node tree) [1] is a spatial access method [2] that supports efficient query processing for high-dimensional data. It supports not only point data but also extended spatial data. The X-tree provides overlap-free split whenever it is possible without allowing the tree to degenerate; otherwise, the X-tree uses extended variable size directory nodes, so-called supernodes. The X-tree may be seen as a hybrid of a linear array-like and a hierarchical R-tree-like directory.

  3. Pure stands of temperate forest tree species modify soil respiration and N turnover

    Directory of Open Access Journals (Sweden)

    N. Brüggemann

    2005-04-01

    Full Text Available The effects of five different tree species common in the temperate zone, i.e. beech (Fagus sylvatica L., pedunculate oak (Quercus robur L., Norway spruce (Picea abies [L.] Karst, Japanese larch (Larix leptolepis [Sichold and Zucc.] Gordon and mountain pine (Pinus mugo Turra, on soil respiration, gross N mineralization and gross nitrification rates were investigated. Soils were sampled in spring and summer 2002 at a forest trial in Western Jutland, Denmark, where pure stands of the five tree species of the same age were growing on the same soil. Soil respiration, gross rates of N mineralization and nitrification were significantly higher in the organic layers than in the Ah horizons for all tree species and both sampling dates. In summer (July, the highest rates of soil respiration, gross N mineralization and gross nitrification were found in the organic layer under spruce, followed by beech > larch > oak > pine. In spring (April, these rates were also higher under spruce compared to the other tree species, but were significantly lower than in summer. For the Ah horizons no clear seasonal trend was observed for any of the processes examined. A linear relationship between soil respiration and gross N mineralization (r2=0.77, gross N mineralization and gross nitrification rates (r2=0.72, and between soil respiration and gross nitrification (r2=0.81 was found. The results obtained underline the importance of considering the effect of forest type on soil C and N transformations.

  4. Variability of Physiological Parameters of European Beech Provenances in International Provenance Trials in Serbia

    Directory of Open Access Journals (Sweden)

    STOJNIĆ, Srdjan

    2010-01-01

    Full Text Available In this study, the variability of physiological parameters of five provenances of Europeanbeech (Fagus sylvatica, which were planted at two locations with different ecological conditions atFruška Gora and Debeli Lug, was estimated. Provenance trials were established in the framework ofCOST Action E52: "Evaluation of Beech Genetic Resources for Sustainable Forestry". 2-3 years oldseedlings originating from Croatia, Germany, Bosnia, Austria and Serbia were planted in blocks offifty plants with a spacing of 2 x 1 m. Physiological parameters such as net photosynthesis, rate oftranspiration and stomatal conductance were measured with a portable gas analysis system. Generally,provenances from Fruška Gora Mountain showed higher intensity of all physiological parameters thanprovenances located at site Debeli Lug. High correlations among rates of net photosynthesis andtranspiration, on one side, and stomatal conductance, on the other side, were found. ANOVA testindicates that variability of net photosynthesis, transpiration and stomatal conductance of investigatedprovenances, at the two locations, was influenced both by environmental conditions of sites andgenetic constitution of provenances.

  5. Tracking the incorporation of 15N from labeled beech litter into mineral-organic associations

    Science.gov (United States)

    Kleber, M.; Hatton, P.; Derrien, D.; Lajtha, K.; Zeller, B.

    2008-12-01

    Nitrogen containing organic compounds are thought to have a role in the complex web of processes that control the turnover time of soil organic matter. The sequential density fractionation technique is increasingly used for the purpose of investigating the association of organic materials with the mineral matrix. Organic materials in the denser fractions (>2.0 kg L-1) typically show 13C NMR signals indicative of carbohydrate and aliphatic structures, an absence of lignin and tannin structures and a narrow C:N ratio, suggesting a microbial origin of organic matter in these fractions. Here we take advantage of a labeling experiment conducted at two different sites in Germany and in France to investigate the incorporation of organic nitrogen into physical fractions of increasing density, representing a proximity gradient to mineral surfaces. 15N labeled beech litter was applied to two acidic forest topsoils 8 and 12 years ago. Although there are differences in the distribution patterns between the two soils, and the majority of the organic nitrogen was recovered in fractions representing organic matter of plant origin and not bound to the mineral matrix, our data clearly show that after a decade, significant amounts of the nitrogen had been incorporated in mineral-organic fractions of supposedly slow turnover. It remains to be shown to which extent the N in the densest fractions was incorporated by soil microbiota and associated with mineral surfaces in organic form or adsorbed to mineral surfaces in inorganic form (NH4+).

  6. Simulation of dye adsorption by beech sawdust as affected by pH.

    Science.gov (United States)

    Batzias, F A; Sidiras, D K

    2007-03-22

    The effect of pH on the batch kinetics of methylene blue adsorption on beech sawdust was simulated, in order to evaluate sawdust potential use as low cost adsorbent for wastewater dye removal. The zero point of charge pH(pzc) of the sawdust, in order to explain the effect of pH in terms of pH(pzc), was measured by the mass titration and the automatic titration methods. The adsorption capacity, estimated according to Freundlich's model, indicate that increase of the pH enhances the adsorption behaviour of the examined material. The lower adsorption of methylene blue at acidic pH is due to the presence of excess H(+) ions that compete with the dye cation for adsorption sites. As the pH of the system increases, the number of positively charged sites decreases while the number of the negatively charged sites increases. The negatively charged sites favour the adsorption of dye cation due to electrostatic attraction. The increase in initial pH from 8.0 to 11.5 increases the amount of dye adsorbed. PMID:16934396

  7. Molten salt pyrolysis of milled beech wood using an electrostatic precipitator for oil collection

    Directory of Open Access Journals (Sweden)

    Heidi S. Nygård

    2015-07-01

    Full Text Available A tubular electrostatic precipitator (ESP was designed and tested for collection of pyrolysis oil in molten salt pyrolysis of milled beech wood (0.5-2 mm. The voltage-current (V-I characteristics were studied, showing most stable performance of the ESP when N2 was utilized as inert gas. The pyrolysis experiments were carried out in FLiNaK and (LiNaK2CO3 over the temperature range of 450-600 ℃. The highest yields of pyrolysis oil were achieved in FLiNaK, with a maximum of 34.2 wt% at 500 ℃, followed by a decrease with increasing reactor temperature. The temperature had nearly no effect on the oil yield for pyrolysis in (LiNaK2CO3 (19.0-22.5 wt%. Possible hydration reactions and formation of HF gas during FLiNaK pyrolysis were investigated by simulations (HSC Chemistry software and measurements of the outlet gas (FTIR, but no significant amounts of HF were detected.

  8. The influence of fire retardants on the properties of beech and poplar veneers and plywood

    Directory of Open Access Journals (Sweden)

    Miljković Jovan

    2005-01-01

    Full Text Available Rising demands for fire resistance properties of wood construction and elements matching new standards have been an important part of building codes during the last decade. On the other side, lack of more detailed research on interaction between wood species and selected fire retardant chemicals even with basically one is evident. This is particularly truth with domestic wood species. In this research, beech and poplar veneers were immersed in 25% solutions of monoammonium phosphate (MP and sodium acetate (SA and impregnated for different periods of time. To determine the preliminary level of fire retardancy achieved in veneers before manufacturing of finished plywood, thermo gravimetric (TG and derivative thermo gravimetric (DTG methods were used. TG and DTG analyses of treated and untreated wood, as well as of fire retardants alone, were performed. The next properties of impregnated and no impregnated veneers and plywood were determined: absorption of imp regnant solution (A, weight percent gain (WPG of imp regnant, equilibrium moisture content (EMC, pH values, and in the case of plywood, strength and fire resistance. Fire resistance of plywood was tested in accordance with standard test for resistance to the effects of fire and the most efficient fire retardant, monoammonium phosphate, had the same result as TG/DTG analyses, which pointed out the validity of TG methods in predicting fire resistance of future products.

  9. Factors affecting industrial wood, material production yield in Turkey’s natural beech forests

    Directory of Open Access Journals (Sweden)

    Atilla Atik

    2014-07-01

    Full Text Available The objectives of the present study are to determine the most important factors affecting industrial wood material production yield in natural oriental beech forests in Turkey using a multifaceted approach and to help entrepreneurs consider these factors to develop more sensitive and realistic production plans. In Günye Forest Management in Bartın province of the West Black Sea Region of Turkey, 41 production units were chosen as the study area. The 1277 ha study area was included in the 2007 and 2010 production management plan. The general state of the stand, natural stand structure, and production methods and tools are the factors thought most strongly affect industrial wood material production yield; 26 variables representing these factors were evaluated in the study. Through multidimensional statistical analyses, including main components, factor and regression  analysis, we found that the most important factors affecting production yield were fertility, aspect of land, skidding method, stand structure, skidding distance, growing stock, transportation and harmful abiotic factors. Production units were divided into three groups based on yield rates and the 26 variables, using discriminate analysis. From the results of the study, a sample model can be developed to help forest managers predict and plan annual industrial wood production more sensitively and realistically.

  10. Radiocarbon-based estimation of soil carbon turnover in a cool-temperate beech forest

    International Nuclear Information System (INIS)

    Soil is the largest pool of terrestrial organic carbon (C) in the biosphere, storing twice as much C as the atmosphere. For deep understanding of the soil organic carbon (SOC) dynamics, we collected surface soil (to 20 cm depth) and litter samples from the Appi forest meteorology research site dominated by Japanese beech (Fagus crenata) in 2005, and then determined their radiocarbon isotope ratios (Δ14C). The Δ14C values of SOC allowed us to estimate their turnover times, further quantifying the rates of heterotrophic respiration by dividing the carbon stocks by the estimated turnover times. Our findings obtained in this study are that: (1) The total annual heterotrophic respiration is 0.38 kgC m-2 y-1 in the site, about two-third of which comes from O horizon storing only 6.3% of total carbon stock; (2) More than 80% of C fixed by vegetation can be re-emitted to the atmosphere from soil within a decade; and (3) The A1 and A2 horizons, having the apparent turnover times of several decades to several centuries, has high potential for C loss from the soil due to warming for a long-term perspective. (author)

  11. Functional significance of tree species diversity and species identity on soil organic carbon, C/N ratio and pH in major European forest types

    DEFF Research Database (Denmark)

    Dawud, Seid Muhie

    Forests provide different ecosystem functions and services including soil carbon sequestration and nutrient supply to maintain growth and productivity. This PhD thesis explored tree species diversity and tree species identity (conifer proportion of basal area) effects on soil C stock and nutrient...... supply (C/N ratio and pH). The studies were carried out in (1) forest floor and mineral soil to 20 cm depth across six different sites of major European forest types based on samples from one to five tree species mixtures along a latitudinal gradient from Spain to Finland, (2) soil profiles down to 40 cm...... within comparable environmental conditions in a Polish forest area, and (3) a trans-boundary approach in adjacent monoculture stands of Douglas-fir and beech at two common garden sites in Denmark. The thesis also included tree species diversity effects on fine root biomass, production and turnover under...

  12. Fault tree handbook

    International Nuclear Information System (INIS)

    This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation

  13. Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly.

    Directory of Open Access Journals (Sweden)

    Andreas Fichtner

    Full Text Available The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica forest by quantifying variation in the intensity of above- (shading and belowground competition (crowding among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.

  14. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jiong; Ibragimov, Rashid

    2015-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

  15. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jian-Ying; Ibragimov, Rashid

    2013-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

  16. Fault-Tree Compiler

    Science.gov (United States)

    Butler, Ricky W.; Boerschlein, David P.

    1993-01-01

    Fault-Tree Compiler (FTC) program, is software tool used to calculate probability of top event in fault tree. Gates of five different types allowed in fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N. High-level input language easy to understand and use. In addition, program supports hierarchical fault-tree definition feature, which simplifies tree-description process and reduces execution time. Set of programs created forming basis for reliability-analysis workstation: SURE, ASSIST, PAWS/STEM, and FTC fault-tree tool (LAR-14586). Written in PASCAL, ANSI-compliant C language, and FORTRAN 77. Other versions available upon request.

  17. Făgetele primare din România, o contribuţie la Patrimoniul Mondial UNESCO [Romania’s primary beech forests, a contribution to UNESCO World Heritage

    Directory of Open Access Journals (Sweden)

    Iovu Adrian Biriș

    2014-08-01

    Full Text Available The World Heritage List (WHL of UNESCO currently comprises 1007 properties in 161 States Parties. Most of these sites are cultural (779 and only 197 are natural sites whereas 31 are mixed sites with outstanding universal cultural and natural values. Romania has only 8 sites registered on WHL of UNESCO, 7 cultural sites and one natural site – The Danube Delta Biosphere Reserve - being underrepresented in relation with the real value of its natural patrimony. Beech is a deciduous species exclusively European and the beech forests constitute the potential natural vegetation for the temperate zone of Europe. Beech forests represent an outstanding and globally unparalleled example of the ongoing ecological processes of post-glacial expansion. This is a key factor for supporting the nomination of beech forests under WHL of UNESCO. Romania, the country with the larges area of beech forests and well preserved primary beech forests, has an important responsibility for the conservation of an adequate and representative network of beech forests. Considering these aspects, the Ministry of the Environment and Climate Change - Department for Waters, Forests and Fisheries, National Forest Administration – Romsilva, Forest Research and Management Institute, WWF Danube-Carpathian Programme Office and Greenpeace CEE Romania Foundation have signed a protocol for collaboration having as target the selection of certain beech forests to be included on the WHL of UNESCO. Keywords

  18. Impacts of age-dependent tree sensitivity and dating approaches on dendrogeomorphic time series of landslides

    Science.gov (United States)

    Šilhán, Karel; Stoffel, Markus

    2015-05-01

    Different approaches and thresholds have been utilized in the past to date landslides with growth ring series of disturbed trees. Past work was mostly based on conifer species because of their well-defined ring boundaries and the easy identification of compression wood after stem tilting. More recently, work has been expanded to include broad-leaved trees, which are thought to produce less and less evident reactions after landsliding. This contribution reviews recent progress made in dendrogeomorphic landslide analysis and introduces a new approach in which landslides are dated via ring eccentricity formed after tilting. We compare results of this new and the more conventional approaches. In addition, the paper also addresses tree sensitivity to landslide disturbance as a function of tree age and trunk diameter using 119 common beech (Fagus sylvatica L.) and 39 Crimean pine (Pinus nigra ssp. pallasiana) trees growing on two landslide bodies. The landslide events reconstructed with the classical approach (reaction wood) also appear as events in the eccentricity analysis, but the inclusion of eccentricity clearly allowed for more (162%) landslides to be detected in the tree-ring series. With respect to tree sensitivity, conifers and broad-leaved trees show the strongest reactions to landslides at ages comprised between 40 and 60 years, with a second phase of increased sensitivity in P. nigra at ages of ca. 120-130 years. These phases of highest sensitivities correspond with trunk diameters at breast height of 6-8 and 18-22 cm, respectively (P. nigra). This study thus calls for the inclusion of eccentricity analyses in future landslide reconstructions as well as for the selection of trees belonging to different age and diameter classes to allow for a well-balanced and more complete reconstruction of past events.

  19. Tree species related functional properties of dissolved and total organic matter in throughfall, stemflow and forest floor solutions

    Science.gov (United States)

    Michalzik, Beate; Bischoff, Sebastian; Schwarz, Martin; Siemens, Jan; Thieme, Lisa; Wilcke, Wolfgang

    2016-04-01

    The amount and chemical nature of water-bound organic matter is a prerequisite for advancing our understanding of the C and nutrient cycling and associated ecosystem processes. While many investigations have addressed the nature and dynamics of DOM in terrestrial ecosystems, only a few have investigated the dynamics and composition of water-bound total OM (TOM) including the particulate organic matter fraction (POM; 0.45 μm material via throughfall (TF), stemflow (SF) and its compositional fate traversing the forest floor (FF) are insufficiently understood. In particular we asked: How do tree species and forest types affect the amount of dissolved and particulate C and N in TF and FF solutions and thus the input into the mineral soil? Do functional properties (e.g. aromaticity) of DOM and TOM differ in TF, SF and FF solutions collected in beech and spruce stands and among different beech stands across Germany? To monitor (mineral) soil input fluxes of DOM and POM in different spruce and beech forests, we fortnightly sampled TF and FF solution over three years (2010-2012) in the "Hainich-Dün-Exploratory", Thuringia, Central Germany, which forms part of the DFG SPP 1374 "Exploratories for Large-scale and Long-term Functional Biodiversity Research". To characterize chemical properties of DOM and TOM, we applied solid-state 13C NMR spectroscopy to TF, SF and FF solutions from three European beech regions across Germany and from Norway spruce sites of the Hainich-Dün-Exploratory. Fluxes of POC and PN were highly variable between years and added significantly to the annual budgets of DOC and DN in TF and FF solutions especially in beech forests. The non-consideration of these particle-bound element fluxes remarkable underestimates the TOC input to the soil by 30 to 40% and those of TN by 10 to 20%. We therefore emphasize the imperative to include POC and PN fluxes into C and N budgeting of forest ecosystems. 13C NMR spectroscopy revealed remarkable tree

  20. Contributions to the phytocoenological study of pure european beech forests in Oraştie river basin (central-western Romania

    Directory of Open Access Journals (Sweden)

    Petru BURESCU

    2012-05-01

    Full Text Available În the current paper we present a phytocoenologic study of the phytocoenoses of the association Festuco drymejaeFagetum Morariu et al. 1968 (Syn.: Fagetum sylvaticae transylvaticum facies with Festuca drymeja I. Pop et al. 1974, found in the pure European beech forests of the Orăştie river basin, lying in the central-western part of Romania. The characterisation of the association under analysis as well as the presentation of the synthetic table have been done byselecting the most representative relevées of pure European beech forests belonging to the Orăştie river basin. The phytocoenoses of these beech forests were analysed in terms of physiognomy and floristic composition, life forms spectrum, floristic elements, and ecological indices.

  1. Tree number estimation with the use of VHR natural colour orthophotos over a heterogeneous landscape in northern Greece

    Science.gov (United States)

    Stournara, P.; Tsakiri-Strati, M.; Siachalou, S.; Doxani, G.; Mallinis, G.; Tsioukas, V.

    2015-04-01

    Spatial explicit knowledge regarding the quantity and the spatial distribution of forest parameters is crucial for sustainable forest management, as well as in fulfilling national reporting needs in the framework of international treaties (i.e. Kyoto Protocol, FAO, EFFIS etc). Especially, tree number which can be used for assessing forest tree density (tree number/ha), is among the most important and laboursome parameters to be measured in the field. The aim of this study is to estimate tree number based on the use of nationwide, freely available, very high spatial resolution orthophotos acquired from Greek National Cadastre and Mapping Agency during the 2007-2009 period. The study area is the University Forest of Taxiarchis, which is located in central Halkidiki, Northern Greece. The dominant species of the forest includes both broadleaves (oak, beech) and coniferous species (Black pine, Calabrian pine), which are found in both pure and mixed stands. Tree crown detection was tested on natural color orthophoto bands in several plots. The principal components and intensity-hue-saturation transformations were also applied in order to enhance tree detection accuracy. Local maxima technique was utilized for tree crown detection. Accuracy results were evaluated based on field plot data available from the official forest management plan of the area completed in 2011. Overall, the detection accuracy exceeded 50% which is deemed satisfactory considering also the heterogeneity of the Mediterranean landscape and the limited spectral resolution of the remote sensing data available.

  2. Response of Soil Respiration to Repeated Extreme Events in a Temperate Beech Forest in Austria

    Science.gov (United States)

    Leitner, S.; Kobler, J.; Holtermann, C.; Zechmeister-Boltenstern, S.; Saronjic, N.; Zimmermann, M.

    2015-12-01

    Climate change research predicts an increase in weather extremes like severe droughts and heavy rainfalls in central Europe. Since soil moisture is one of the most important drivers of soil respiration, a change in precipitation regime is likely to influence ecosystem C cycling. During drying of soils, soil microbial activity decreases and dead microbial cells, osmolytes, and semi-decomposed organic matter accumulate. When dry soils are rewetted, this easily-decomposable C leads to a pulse in soil respiration, a phenomenon known as "Birch-effect". In terms of annual soil CO2emissions, it is not clear whether these post-wetting respiration pulses outweigh or even overcompensate preceding drought-induced reductions in soil respiration. To investigate the impact of repeated drought and heavy rainfall events, a two-year precipitation manipulation experiment was conducted in an Austrian beech forest. Experimental plots were covered with transparent roofs to exclude rainfall, and an irrigation system was used to simulate heavy rainfall events. Control plots received natural precipitation. Soil respiration was monitored 3-hourly with an automatic static chamber system connected to an infrared CO2 analyzer. Soil temperature (Tsoil) and volumetric water content (VWC) were recorded with a datalogger. Various statistical models were tested to describe the relationship between soil respiration, Tsoiland VWC. Our results showed that repeated extreme events strongly reduced variation in soil respiration. Droughts significantly reduced soil respiration, and reductions depended on the length of the drought period. Post-wetting respiration pulses did not outweigh drought-induced reductions. Temperature sensitivity of soil respiration was best described with a Lloyd & Taylor model. Furthermore, in stressed plots VWC became limiting for soil respiration. Overall, our data corroborate the importance of the precipitation regime for soil respiration.

  3. Relaxed molecular clock provides evidence for long-distance dispersal of Nothofagus (southern beech.

    Directory of Open Access Journals (Sweden)

    Michael Knapp

    2005-01-01

    Full Text Available Nothofagus (southern beech, with an 80-million-year-old fossil record, has become iconic as a plant genus whose ancient Gondwanan relationships reach back into the Cretaceous era. Closely associated with Wegener's theory of "Kontinentaldrift", Nothofagus has been regarded as the "key genus in plant biogeography". This paradigm has the New Zealand species as passengers on a Moa's Ark that rafted away from other landmasses following the breakup of Gondwana. An alternative explanation for the current transoceanic distribution of species seems almost inconceivable given that Nothofagus seeds are generally thought to be poorly suited for dispersal across large distances or oceans. Here we test the Moa's Ark hypothesis using relaxed molecular clock methods in the analysis of a 7.2-kb fragment of the chloroplast genome. Our analyses provide the first unequivocal molecular clock evidence that, whilst some Nothofagus transoceanic distributions are consistent with vicariance, trans-Tasman Sea distributions can only be explained by long-distance dispersal. Thus, our analyses support the interpretation of an absence of Lophozonia and Fuscospora pollen types in the New Zealand Cretaceous fossil record as evidence for Tertiary dispersals of Nothofagus to New Zealand. Our findings contradict those from recent cladistic analyses of biogeographic data that have concluded transoceanic Nothofagus distributions can only be explained by vicariance events and subsequent extinction. They indicate that the biogeographic history of Nothofagus is more complex than envisaged under opposing polarised views expressed in the ongoing controversy over the relevance of dispersal and vicariance for explaining plant biodiversity. They provide motivation and justification for developing more complex hypotheses that seek to explain the origins of Southern Hemisphere biota.

  4. Particulate matter in terrestrial solutions: insights from a European beech forest in Germany

    Science.gov (United States)

    Levia, Delphis; Michalzik, Beate; Bischoff, Sebastian; Näthe, Kerstin; Gruselle, Marie-Cecile; Legates, David; Richter, Susanne

    2015-04-01

    Particulate matter (PM) can affect the functional ecology and health of forest ecosystems. Nonetheless, the cycling of particulate matter is usually neglected in studies examining the biogeochemistry of forest ecosystems. The size and shape of PM has been documented to influence both its impaction on forest canopies and its biogeochemical reactivity. So what is the size and shape of PM in bulk precipitation, throughfall, stemflow, and Oa solution? An answer to this question is of prime importance to those wishing to better model the biogeochemistry of forests. This presentation examines the nature of PM in terrestrial solutions from a European beech (Fagus sylvatica L.) in east-central Germany during the leafed and leafless periods. Scanning electron microscopy, image processing, and data analysis permitted quantification of the size and shape of PM in forest solutions. Building upon the work of Levia et al. [2013]* who quantified the diameter distributions of 43,278 individual particulates in bulk precipitation, throughfall, stemflow, and Oa soil solution, this work delves into surface area, roundness, and perimeter of PM in terrestrial solutions. Initial analyses have revealed that there are marked differences in the geometry of PM in bulk precipitation, throughfall, stemflow, and Oa solutions with implications for biogeochemical modeling of PM flux in forests. --------------- * Levia, D.F., Michalzik, B., Bischoff, S., Näthe, K., Legates, D.R., Gruselle, M.C-. and Richter, S. 2013. Measurement and modeling of diameter distributions of particulate matter in terrestrial solutions. Geophysical Research Letters 40(7): 1317-1321. [DOI: 10.1002/grl.50305] Funding note: This work was funded by the Alexander von Humboldt Foundation.

  5. Significance of tree roots for preferential infiltration in stagnic soils

    Directory of Open Access Journals (Sweden)

    B. Lange

    2008-08-01

    Full Text Available It is generally believed that roots have an effect on infiltration. In this study we analysed the influence of tree roots from Norway spruce (Picea abies (L. Karst, silver fir (Abies alba Miller and European beech (Fagus sylvatica L. on preferential infiltration in stagnic soils in the northern pre-Alps in Switzerland. We conducted irrigation experiments (1 m2 and recorded water content variations with time domain reflectrometry (TDR. A rivulet approach was applied to characterise preferential infiltration. Roots were sampled down to a depth of 0.5 to 1 m at the same position where the TDR-probes had been inserted and digitally measured. The basic properties of preferential infiltration, film thickness of mobile water and the contact length between soil and mobile water in the horizontal plane are closely related to fine root densities. An increase in root density resulted in an increase in contact length, but a decrease in film thickness. We modelled water content waves based on fine root densities and identified a range of root densities that lead to a maximum volume flux density and infiltration capacity. These findings provide convincing evidence that tree roots improve soil structure and thus infiltration.

  6. Uniform random spanning trees

    OpenAIRE

    Pemantle, Robin

    2004-01-01

    There are several good reasons you might want to read about uniform spanning trees, one being that spanning trees are useful combinatorial objects. Not only are they fundamental in algebraic graph theory and combinatorial geometry, but they predate both of these subjects, having been used by Kirchoff in the study of resistor networks. This article addresses the question about spanning trees most natural to anyone in probability theory, namely what does a typical spanning tree look like?

  7. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... as possible. Evaluations show that the proposed protocol provides considerable gains over the standard tree splitting protocol applying SIC. The improvement comes at the expense of an increased feedback and receiver complexity....

  8. Major characteristics of mixed fir and beech virgin forests in the National park Biogradska Gora in Montenegro

    Directory of Open Access Journals (Sweden)

    Čurović Milić

    2011-01-01

    Full Text Available In order to manage forest ecosystems at a sufficiently high biodiversity level it is necessary to study the ecological, structural and production characteristics of virgin forests. The research was directed towards identifying the characteristics of mixed fir and beech forests (Abieti-Fagetum s. lat. in the area of the strict reserve of the National Park Biogradska Gora in Montenegro. Basic characteristics of these forests were researched in the process of definition of forest types. In this manner, it is for the first time that a realistic base for typological management of forests and forest ecosystems with similar ecological and structural characteristics was provided for the specific sites.

  9. SOME SITE CHARACTERISTICS OF EASTERN BEECH (Fagus orientalis Lipsky.) FORESTS ON TÜRKMEN MOUNTAIN (EVKONDU HILL)

    OpenAIRE

    GÖL, Ceyhun; ÇELİK, Nejat; ÇAKIR, Meriç; GÜL, Ebru

    2009-01-01

    The purpose of this research is to investigate some site conditions of eastern beech (Fagus orientalis Lipsky) forests and to determine some relationships between soil, plant and forest floor on Evkondu hill located on Türkmen Mountain of Eskişehir province. This study was carried out at 20x10 m size sample plots on upper, middle and bottom slopes of hill at north aspect. Soil, and forest floor samples were collected from these sample plots. It was observed that distribution of Fagus oriental...

  10. Winter Birch Trees

    Science.gov (United States)

    Sweeney, Debra; Rounds, Judy

    2011-01-01

    Trees are great inspiration for artists. Many art teachers find themselves inspired and maybe somewhat obsessed with the natural beauty and elegance of the lofty tree, and how it changes through the seasons. One such tree that grows in several regions and always looks magnificent, regardless of the time of year, is the birch. In this article, the…

  11. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  12. The Wish Tree Project

    Science.gov (United States)

    Brooks, Sarah DeWitt

    2010-01-01

    This article describes the author's experience in implementing a Wish Tree project in her school in an effort to bring the school community together with a positive art-making experience during a potentially stressful time. The concept of a wish tree is simple: plant a tree; provide tags and pencils for writing wishes; and encourage everyone to…

  13. Distributed Contour Trees

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Dmitriy; Weber, Gunther H.

    2014-03-31

    Topological techniques provide robust tools for data analysis. They are used, for example, for feature extraction, for data de-noising, and for comparison of data sets. This chapter concerns contour trees, a topological descriptor that records the connectivity of the isosurfaces of scalar functions. These trees are fundamental to analysis and visualization of physical phenomena modeled by real-valued measurements. We study the parallel analysis of contour trees. After describing a particular representation of a contour tree, called local{global representation, we illustrate how di erent problems that rely on contour trees can be solved in parallel with minimal communication.

  14. Trees in Lhasa

    Institute of Scientific and Technical Information of China (English)

    Degyi

    2008-01-01

    Trees are flourishing in Lhasa wherever the history exists. There is such a man. He has already been through cus-toms after his annual trek to Lhasa, which he has been doing for over twenty years in succession to visit his tree.Although he has been making this journey for so long,it is neither to visit friends or family,nor is it his hometown.It is a tree that is tied so profoundly to his heart.When the wind blows fiercely on the bare tree and winter snow falls,he stands be-fore the tree with tears of jo...

  15. Response of soil microbial community composition to afforestation with pure and mixed tree species

    Science.gov (United States)

    Gunina, Anna; Smith, Andrew; Godbold, Douglas; Kuzyakov, Yakov; Jones, Davey

    2016-04-01

    Afforestation of agricultural land affects soil ecosystem functions by inducing carbon (C) and nitrogen (N) sequestration and promoting shifts in microbial community structure. Soil C and N stocks undergo progressive changes over several decades after forest establishment, particularly in successional forests. In contrast, microbial community structure can be shifted already in the first decade and thus, direct effect of tree species can be revealed. Thus, the aim of this study was to determine how soil microbial community composition is altered by afforestation with either one, two or three species mixtures of trees, which possess strongly contrasting functional traits. The study was conducted at the BangorDIVERSE temperate forest experiment established in 2004 on a former arable soil. Soil samples were collected under single, two and three species mixtures of alder, birch, beech and oak, while contiguous field was chosen as a control. Soil samples were analysed for key quality indicators (total C and N, pH, nitrate and ammonium), and microbial community structure was determined by phospholipid fatty acids (PLFAs) analysis. Ten years after afforestation, total soil C, N and C/N ratios were not strongly affected, with the highest positive changes (up to 20%) for the birch, alder+oak and birch+beech plots. Decrease of C and N contents were observed for the pure beech plot. pH decreased by 1-1.2 units for all forest plots compare to the control soil. Total PLFAs content (370-630 nmol g‑1 soil) increased in comparison to the control (315 nmol g‑1 soil), resulting in the changes in total PLFAs content from 20 to 100%. Thus, changes of chemical properties (C, N) occur slower than changes of microbial biomarkers at the early stage of afforestation. Bacterial PLFA content was shifted by 20-120%, whereas fungal PLFAs were changed by 50-300%, reflecting stronger impact of afforestation on the recovery of fungal communities than on bacterial. Principal component analysis

  16. Growth of a Pine Tree

    Science.gov (United States)

    Rollinson, Susan Wells

    2012-01-01

    The growth of a pine tree is examined by preparing "tree cookies" (cross-sectional disks) between whorls of branches. The use of Christmas trees allows the tree cookies to be obtained with inexpensive, commonly available tools. Students use the tree cookies to investigate the annual growth of the tree and how it corresponds to the number of whorls…

  17. Effect of a long-term afforestation of pine in a beech domain in NE-Spain revealed by analytical pyrolysis (Py-GC/MS)

    Science.gov (United States)

    Girona García, Antonio; Badía-Villas, David; Tomás Jiménez-Morillo, Nicasio; Martí-Dalmau, Clara; González-Pérez, José Antonio

    2015-04-01

    The replacement of native beech forests (Fagus sylvatica) by Scots pine (Pinus sylvestris) afforestation may exert changes in soil properties, particularly in soil organic matter (SOM) [1]. It is known that the products generated by Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) pyrolysis of organic matter are related to their origin [2 and references therein]. Therefore this technique can be used to investigate said changes. In this work, Py-GC/MS is used to study changes in SOM quality surrogated to the effect of the centennial replacement of beech by Scots pine. The soils studied were two acid soil profiles developed on quartzites under a humid climate at an altitude of 1400-1500 masl from Moncayo (Iberian range, NE-Spain). For each soil profile three organic layers (litter: OL, fragmented litter OF and humified litter OH) and the mineral soil horizons (Ah, E, Bhs and C) were sampled. After 100 years since the pine afforestation, differences in the relative abundance of lipids released by pyrolysis were observed in the O-layers ranging from 3.82-7.20% in pine soils and 0.98-1.25% in beech soils. No differences were observed in mineral horizons with depth except for the C horizons where beech lipid content was much higher (21.25%) than in that under pine (1.07%). Both pine and beech soils show similar nitrogen compounds relative contents along the soil profile, increasing from OL to Ah (3.49-9.11% and 2.75-11.73% in beech and pine respectively) with a conspicuous reduction in the E horizon. It is remarkable the absence of nitrogen compounds in beech Bhs and C horizons. The relative content of aromatic compounds in O-layers show opposite trends for beech and pine; an enrichment in aromatic compounds is observed in beech OL layer (12.39%) decreasing to 4.11% in OH layer in contrast, whereas for pine O-layers the aromatic compounds relative abundance was higher in the OH (5.83%) than in the OL layer (2.8%). Mineral Ah and E horizons show similar values in

  18. Mode I Critical Stress Intensity Factor of Beech Wood (Fagus Sylvatica in a TL Configuration: A Comparison of Different Methods

    Directory of Open Access Journals (Sweden)

    Miran Merhar, Dominika Gornik Bučar, Bojan Buča

    2013-09-01

    Full Text Available The paper presents a comparison between various methods of mode I critical stress intensity factor KIC calculations of beech wood in the TL configuration. The first method is the stress intensity factor extrapolation to the distance of 0 mm from the crack tip; the second method is the use of the J integral; and the third method is based on the differences in deformation energies from which the strain energy release rate per unit of crack propagation length was obtained. The fourth method is the calculation of material deformation around the crack or the displacement of the triangle element node; and the fifth method uses a generally known equation for the CT specimen for plane-strain conditions in isotropic material. Using the finite element method, it was found that the J integral was least sensitive to the size and shape of the elements. It was used to calculate the critical stress intensity factor KIC for beech wood in a TL configuration. The average value is 0.56 MPa√m with a standard deviation of 0.047 MPa√m.

  19. Use of sap flow measurements to validate stomatal functions for mature beech (Fagus sylvatica) in view of ozone uptake calculations

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Sabine, E-mail: sabine.braun@iap.c [Institute for Applied Plant Biology, Sangrubenstrasse 25, CH-4124 Schoenenbuch (Switzerland); Schindler, Christian [Swiss Tropical and Public Health Institute, University of Basel, Socinstrasse 57, CH-4051 Basel (Switzerland); Leuzinger, Sebastian [Forest Ecology, Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetsstr. 16, 8092 Zuerich (Switzerland)

    2010-09-15

    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 stomatal conductance as the boundary layer resistance in forests is usually small. Based on this relative conductance, stomatal functions to describe the dependence on light, temperature, vapour pressure deficit and soil moisture were derived using multivariate nonlinear regression. These functions were validated by comparison with conductance values directly estimated from sap flow. The results corroborate the current flux parameterization for beech used in the DO{sub 3}SE model. - A method was developed to derive stomatal functions and ozone uptake calculation from sap flow.

  20. From gene trees to species trees II: Species tree inference in the deep coalescence model

    OpenAIRE

    Zhang, Louxin

    2010-01-01

    When gene copies are sampled from various species, the resulting gene tree might disagree with the containing species tree. The primary causes of gene tree and species tree discord include lineage sorting, horizontal gene transfer, and gene duplication and loss. Each of these events yields a different parsimony criterion for inferring the (containing) species tree from gene trees. With lineage sorting, species tree inference is to find the tree minimizing extra gene lineages that had to coexi...

  1. Black carbon surface oxidation and organic composition of beech-wood soot aerosols

    Science.gov (United States)

    Corbin, J. C.; Lohmann, U.; Sierau, B.; Keller, A.; Burtscher, H.; Mensah, A. A.

    2015-10-01

    composition of the BC was approximately constant across all stages of combustion for both fresh and aged samples. These results represent the first time-resolved measurements of in situ BC surface aging and suggest that the surface of beech-wood BC may be modelled as a single chemical species.

  2. Comparison of drought stress indices in beech forests: a modelling study

    Directory of Open Access Journals (Sweden)

    Vilhar U

    2016-08-01

    Full Text Available Two drought stress indices were applied to managed as well as old-growth beech forests and gaps for the 2001 to 2013 period to aid in the development of an efficient tool for field water supply diagnosis. The relative extractable soil water (REW, which was calculated from the soil water content in the root zone, and the transpiration index (TI, calculated as the ratio between the actual and potential transpiration were used. Both indices were calculated on a daily basis using the water balance model BROOK90, which was fitted and tested using measured data on throughfall and soil water content. A sensitivity analysis apportioned to the input parameters of the drought stress indices was conducted to assess uncertainty. Both drought stress indices showed the greatest drought stress in the years 2009, 2003 and 2011, as also indicated by the Standardized Precipitation Evapotranspiration Index (SPEI at the nearest meteorological station. However, drought stress intensity and duration differed between the indices and study sites. Greater water supply stress was shown in the forests than the gaps. Furthermore, the agreement among the indices was smaller for gaps compared with forests, which implies that careful index selection is needed when comparing water supply stresses in different stages of forest stand development. Due to the low amount of input data required and the parameters that can be measured with relative ease in the field, REW might be an efficient tool for field water supply diagnosis when analyzing the drought stresses of similar forest types and at unique stages of development. REW satisfactorily indicated drought stress in forests but to a lesser extent in gaps. TI demonstrated more consistent differences in drought stress between forests and gaps and therefore proved to be the appropriate index for a detailed analysis of drought stress variation between different stages of forest stand development. However, due to a greater number of

  3. Black-carbon-surface oxidation and organic composition of beech-wood soot aerosols

    Directory of Open Access Journals (Sweden)

    J. C. Corbin

    2015-03-01

    Full Text Available Soot particles are the most strongly light-absorbing particles commonly found in the atmosphere. They are major contributors to the radiative budget of the Earth and to the toxicity of atmospheric pollution. Atmospheric aging of soot may change its health- and climate-relevant properties by oxidizing the primary black carbon (BC or organic particulate matter (OM which, together with ash, comprise soot. This atmospheric aging, which entails the condensation of secondary particulate matter as well as the oxidation of the primary OM and BC emissions, is currently poorly understood. In this study, atmospheric aging of wood-stove soot aerosols was simulated in a continuous-flow reactor. The composition of fresh and aged soot particles was measured in real time by a dual-vaporizer aerosol-particle mass spectrometer (SP-AMS. The SP-AMS provided information on the OM, BC, and surface composition of the soot. The OM appeared to be generated largely by cellulose and/or hemicellulose pyrolysis, and was only present in large amounts when new wood was added to the stove. BC signals otherwise dominated the mass spectrum. These signals consisted of ions related to refractory BC (rBC, C+1−5, oxygenated surface groups (CO+1−2, potassium (K+ and water (H+2O and related fragments. The C+4 : C+3 ratio, but not the C+1 : C+3 ratio, was consistent with the BC-structure trends of Corbin et al. (2015c. The CO+1−2 signals likely originated from BC surface groups: upon aging, both CO+ and CO+2 increased relative to C+1−3 while CO+2 simultaneously increased relative to CO+. Factor analysis (PMF of SP-AMS and AMS data, using a new error model to account for peak-integration uncertainties, indicated that the surface composition of the BC was approximately constant across all stages of combustion for both fresh and aged samples. These results represent the first time-resolved measurements of in-situ BC-surface aging and suggest that the surface of beech-wood BC may

  4. Nitrogen oxides emission from two beech forests subjected to different nitrogen loads

    Directory of Open Access Journals (Sweden)

    B. Kitzler

    2006-01-01

    Full Text Available We analysed nitrogen oxides (N2O, NO and carbon dioxide (CO2 emissions from two beech forest soils close to Vienna, Austria, which were exposed to different nitrogen input from the atmosphere. The site Schottenwald (SW received 20.2 kg N ha−1 y−1 and Klausenleopoldsdorf (KL 12.6 kg N ha−1 y−1 through wet deposition. Nitric oxide emissions from soil were measured hourly with an automatic dynamic chamber system. Daily N2O measurements were carried out by an automatic gas sampling system. Measurements of nitrous oxide (N2O and CO2 emissions were conducted over larger areas on a biweekly (SW or monthly (KL basis by manually operated chambers. We used an autoregression procedure (time-series analysis for establishing time-lagged relationships between N-oxides emissions and different climate, soil chemistry and N-deposition data. It was found that changes in soil moisture and soil temperature significantly effected CO2 and N-oxides emissions with a time lag of up to two weeks and could explain up to 95% of the temporal variations of gas emissions. Event emissions after rain or during freezing and thawing cycles contributed significantly (for NO 50% to overall N-oxides emissions. In the two-year period of analysis the annual gaseous N2O emissions at SW ranged from 0.64 to 0.79 kg N ha−1 y−1 and NO emissions were 0.24 to 0.49 kg N ha−1 per vegetation period. In KL significantly lower annual N2O emissions (0.52 to 0.65 kg N2O-N kg ha−1 y−1 as well as considerably lower NO-emissions were observed. During a three-month measurement campaign NO emissions at KL were 0.02 kg N ha−1, whereas in the same time period significantly more NO was emitted in SW (0.32 kg NO-N ha−1. Higher N-oxides emissions, especially NO emissions from the high N-input site (SW may indicate that atmospheric deposition has an impact on emissions of gaseous N from our forest soils. At KL there was a strong correlation between N-deposition and N-emission over time

  5. Ammonia emissions from beech forest after leaf fall – measurements and modelling

    Directory of Open Access Journals (Sweden)

    K. Hansen

    2012-11-01

    Full Text Available The understanding of biochemical feed-back mechanisms in the climate system is lacking knowledge in relation to bi-directional ammonia (NH3 exchange between natural ecosystems and the atmosphere. We therefore study the atmospheric NH3 fluxes during a 25 days period during autumn 2010 (21 October–15 November for the Danish beech forest, Lille Bøgeskov, to address the hypothesis that NH3 emissions occur from deciduous forests in relation to leaf fall. This is accomplished by using observations of vegetation status, NH3 fluxes and model calculations. Vegetation status was observed using plant area index (PAI and leaf area index (LAI. NH3 fluxes were measured using the relaxed eddy accumulation (REA method. The REA based NH3 concentrations were compared to NH3 denuder measurements. Model calculations were obtained with the Danish Ammonia MOdelling System (DAMOS. 57.7% of the fluxes measured showed emission and 19.5% showed deposition. The mean NH3 flux was 0.087 ± 0.19 μg NH3-N m−2 s−1. A clear tendency of the flux going from negative (deposition to positive (emission fluxes of up to 0.96 ± 0.40 μg NH3-N m−2 s−1 throughout the measurement period was found. In the leaf fall period (23 October–8 November, an increase in the atmospheric NH3 concentrations was related to the increasing forest NH3 flux. The modelled concentration from DAMOS fits well the measured concentrations before leaf fall. During and after leaf fall, the modelled concentrations are too low. The results indicate that the missing contribution to atmospheric NH3 concentration from vegetative surfaces related to leaf fall are of a relatively large magnitude. We therefore conclude that emissions from deciduous forests are important to include in model calculations of atmospheric NH

  6. Inter-specific competition in mixed forests of Douglas-fir (Pseudotsuga menziesii) and common beech (Fagus sylvatica) under climate change – a model-based analysis

    NARCIS (Netherlands)

    Reyer, C.; Lasch, P.; Mohren, G.M.J.; Sterck, F.J.

    2010-01-01

    Mixed forests feature competitive interactions of the contributing species which influence their response to environmental change. • We analyzed climate change effects on the inter-specific competition in a managed Douglas-fir/beech mixed forest. • Therefore, we initialised the process-based forest

  7. Below-ground effects of enhanced tropospheric ozone and drought in a beech/spruce forest (Fagus sylvatica L. / Picea abies [L.] Karst)

    Science.gov (United States)

    The effects of experimentally elevated O3 on soil respiration rates, standing fine-root biomass, fine-root production and δ13C signature of newly produced fine roots were investigated in an adult European beech/Norway spruce forest in Germany during two subsequent years with cont...

  8. Modelling exploratio of the future of European beech (Fagus sylvatica L.) under climate change - Range, abundance, genetic diversity and adaptive response

    NARCIS (Netherlands)

    Kramer, K.; Degen, B.; Buschbom, J.; Hickler, T.; Thuiller, W.; Sykes, M.T.; Winter, de W.P.

    2010-01-01

    We explored impacts of climate change on the geographic distribution of European beech by applying state of the art statistical and process-based models, and assessed possible climate change impacts on both adaptive capacity in the centre of its distribution and adaptive responses of functional trai

  9. Lignin properties in topsoils of a beech/oak forest after 8 years of manipulated litter fall: relevance of altered input and oxidation of lignin

    NARCIS (Netherlands)

    T. Klotzbücher; S. Strohmeier; K. Kaiser; R.D. Bowden; K. Lajtha; H. Ohm; K. Kalbitz

    2013-01-01

    Background and aims We studied the response of lignin oxidation in soils of a beech/oak forest to changes in litter fall. Additionally we considered possible factors in lignin oxidation, including altered (i) input of fresh organic matter and (ii) fungi-to-bacteria ratios. Methods The field-based ex

  10. Carbon flux to woody tissues in a beech/spruce forest during summer and in response to chronic O3 exposure

    Science.gov (United States)

    The present study compares the dynamics in carbon (C) allocation of adult deciduous beech (Fagus sylvatica) and evergreen spruce (Picea abies) during summer and in response to seven-year-long exposure with twice-ambient ozone (O3) concentrations (2 × O3). Focus was on the respira...

  11. Significant light and temperature dependent monoterpene emissions from European beech (fagus sylvatiga L.) and their potential impact on the European VOC budget

    NARCIS (Netherlands)

    Dindorf, T.; Kuhn, U.; Ganzeveld, L.N.; Schebeske, G.; Ciccioli, P.; Holzke, C.; Köble, R.; Seufert, G.; Kesselmeier, J.

    2006-01-01

    By using a dynamic branch enclosure system the emission of monoterpenes from European beech (Fagus sylvatica L.) was investigated during two consecutive summer vegetation periods in the years of 2002 and 2003 in Germany. All measurements were performed under field conditions within the framework of

  12. Regions of provenance of European beech (Fagus sylvatica L.) in Europe

    NARCIS (Netherlands)

    Aunon, F.J.; Garcia del Barrio, J.M.; Mancha, J.A.; Vries, de S.M.G.; Alia, R.

    2011-01-01

    The European Council Directive 1999/105/CE, concerning the marketing of forest reproductive material, establishes a Region of Provenance as the basic unity for trading tree reproductive materials (fruits, seeds or plants) and defines it as “the area or group of areas subjected to sufficiently unifor

  13. The valuative tree

    CERN Document Server

    Favre, Charles

    2004-01-01

    This volume is devoted to a beautiful object, called the valuative tree and designed as a powerful tool for the study of singularities in two complex dimensions. Its intricate yet manageable structure can be analyzed by both algebraic and geometric means. Many types of singularities, including those of curves, ideals, and plurisubharmonic functions, can be encoded in terms of positive measures on the valuative tree. The construction of these measures uses a natural tree Laplace operator of independent interest.

  14. Trees in renorming theory

    OpenAIRE

    Haydon, Richard

    1995-01-01

    Trees are very agreeable objects to work with, offering a diversity of behaviour within a structure that is sufficiently simple to admit precise analysis. Thus we are able to offer fairly satisfactory necessary and sufficient conditions on a tree $\\Upsilon $ for the existence of equivalent LUR or strictly convex norms on $\\C_0(\\Upsilon )$ and for norms with the Kadec Property. In particular, we show that for a {\\sl finitely branching} tree $\\Upsilon $ the space $\\C_0(\\Upsilon )$ admits a Kade...

  15. Generalized Binomial Trees

    OpenAIRE

    Jackwerth, Jens Carsten

    1996-01-01

    We consider the problem of consistently pricing new options given the prices of related options on the same stock. The Black-Scholes formula and standard binomial trees can only accommodate one related European option which then effectively specifies the volatility parameter. Implied binomial trees can accommodate only related European options with the same time-to-expiration.The generalized binomial trees introduced here can accommodate any kind of related options (European, American, or exo...

  16. Influences of calcium availability and tree species on Ca isotope fractionation in soil and vegetation

    Science.gov (United States)

    Page, B.D.; Bullen, T.D.; Mitchell, M.J.

    2008-01-01

    The calcium (Ca) isotope system is potentially of great use for understanding biogeochemical processes at multiple scales in forest ecosystems, yet remains largely unexplored for this purpose. In order to further our understanding of Ca behavior in forests, we examined two nearly adjacent hardwood-dominated catchments with differing soil Ca concentrations, developed from crystalline bedrock, to determine the variability of 44Ca/ 40Ca ratios (expressed as ??44Ca) within soil and vegetation pools. For both sugar maple and American beech, the Ca isotope compositions of the measured roots and calculated bulk trees were considerably lighter than those of soil pools at these sites, suggesting that the trees were able to preferentially take up light Ca at the root-soil interface. The Ca isotope compositions of three of four root samples were among the lightest values yet reported for terrestrial materials (??44Ca ???-3.95???). Our results further indicate that Ca isotopes were fractionated along the transpiration streams of both tree species with roots having the least ??44Ca values and leaf litter the greatest. An approximately 2??? difference in ??44Ca values between roots and leaf litter of both tree species suggests a persistent fractionation mechanism along the transpiration stream, likely related to Ca binding in wood tissue coupled with internal ion exchange. Finally, our data indicate that differing tree species demand for Ca and soil Ca concentrations together may influence Ca isotope distribution within the trees. Inter-catchment differences in Ca isotope distributions in soils and trees were minor, indicating that the results of our study may have broad transferability to studies of forest ecosystems in catchments developed on crystalline substrates elsewhere. ?? 2008 Springer Science+Business Media B.V.

  17. D2-tree

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Sioutas, Spyros; Pantazos, Kostas;

    2015-01-01

    We present a new overlay, called the Deterministic Decentralized tree (D2-tree). The D2-tree compares favorably to other overlays for the following reasons: (a) it provides matching and better complexities, which are deterministic for the supported operations; (b) the management of nodes (peers......-balancing scheme of elements into nodes is deterministic and general enough to be applied to other hierarchical tree-based overlays. This load-balancing mechanism is based on an innovative lazy weight-balancing mechanism, which is interesting in its own right....

  18. The tree BVOC index

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, J.R., E-mail: jrsimpson@ucdavis.edu [U.S. Forest Service, Pacific Southwest Research Station, Urban Ecosystems and Processes, 1731 Research Park Drive, Davis, CA 95616 (United States); McPherson, E.G. [U.S. Forest Service, Pacific Southwest Research Station, Urban Ecosystems and Processes, 1731 Research Park Drive, Davis, CA 95616 (United States)

    2011-08-15

    Urban trees can produce a number of benefits, among them improved air quality. Biogenic volatile organic compounds (BVOCs) emitted by some species are ozone precursors. Modifying future tree planting to favor lower-emitting species can reduce these emissions and aid air management districts in meeting federally mandated emissions reductions for these compounds. Changes in BVOC emissions are calculated as the result of transitioning to a lower-emitting species mix in future planting. A simplified method for calculating the emissions reduction and a Tree BVOC index based on the calculated reduction is described. An example illustrates the use of the index as a tool for implementation and monitoring of a tree program designed to reduce BVOC emissions as a control measure being developed as part of the State Implementation Plan (SIP) for the Sacramento Federal Nonattainment Area. - Highlights: > A Tree BVOC index based on reduced emissions from low emitting trees is described. > An example illustrates use of the index as an implementation and monitoring tool. > This index could be useful for including urban trees in air quality mitigation plans. - A tree BVOC index is presented that calculates reduced BVOC emissions from planting lower-emitting urban tree species that has potential application for SIP compliance.

  19. Symmetric M-tree

    CERN Document Server

    Sexton, Alan P

    2010-01-01

    The M-tree is a paged, dynamically balanced metric access method that responds gracefully to the insertion of new objects. To date, no algorithm has been published for the corresponding Delete operation. We believe this to be non-trivial because of the design of the M-tree's Insert algorithm. We propose a modification to Insert that overcomes this problem and give the corresponding Delete algorithm. The performance of the tree is comparable to the M-tree and offers additional benefits in terms of supported operations, which we briefly discuss.

  20. A theory of game trees, based on solution trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie); A. Plaat (Aske)

    1996-01-01

    textabstractIn this paper a complete theory of game tree algorithms is presented, entirely based upon the notion of a solution tree. Two types of solution trees are distinguished: max and min solution trees respectively. We show that most game tree algorithms construct a superposition of a max and a

  1. Retranslocation of foliar nutrients of deciduous tree seedlings in different soil condition under free-air O3 enrichment

    Directory of Open Access Journals (Sweden)

    Shi C

    2016-06-01

    Full Text Available Retranslocation is the amount of an element that is depleted from old plant components and is provided for new growth. Leaf senescence is usually accelerated at elevated O3 (eO3, and leaf shedding is influenced by soil nutrient availability (and acidification. In this study, we focused on the net retranslocation and allocation dynamics of foliar nutrients (N, P, Mg, K, Ca, Mn, Fe and Al to investigate the effect of eO3 on birch (Betula platyphylla var. japonica, oak (Quercus mongolica var. crispula, and beech (Fagus crenata seedlings grown in different soil conditions. Seedlings of the 3 species were planted in a free-air O3 enrichment system under 3 soil types (brown forest soil, serpentine soil, volcanic ash soil for one growing season. All tree species were grown with 3 replications per each plot at elevated O3 (about 80 ppb and ambient condition (O3 ranging 25-35 ppb. Leaf samples were taken from the top part of seedlings during the growing season in mid-September, and senescing leaves were sampled in mid-November. Both were collected for chemical composition analysis. Retranslocation rate of P was markedly increased by eO3 in birch and significantly differed among soil types in oak seedlings, while was constant across treatments in beech seedlings. Retranslocation of N in oak seedlings was significantly affected by soil type. Retranslocation of other elements was most sensitive to both eO3 and soil type in beech seedlings. The influence of differential growth patterns among species in modulating the physiological response of seedlings to high levels of ozone and different soil conditions are discussed.

  2. Nitrogen oxides emission from two beech forests subjected to different nitrogen loads

    Directory of Open Access Journals (Sweden)

    B. Kitzler

    2005-09-01

    Full Text Available We analysed nitrogen oxides (N2O, NO and NO2 and carbon dioxide (CO2 emissions from two beech forest soils close to Vienna, Austria, which were exposed to different nitrogen input from the atmosphere. The site Schottenwald (SW received 22.6 kg N y-1 and Klausenleopoldsdorf (KL 13.5 kg N y-1 through wet and dry deposition. Nitrogen oxide emissions from soil were measured hourly with an automatic dynamic chamber system. Daily N2O measurements were carried out by an automatic gas sampling system. Measurements of nitrous oxide (N2O and CO2 emissions were conducted over larger areas on a biweekly (SW or monthly (KL basis by manually operated chambers. We used an autoregression procedure (time-series analysis for establishing time-lagged relationships between N-oxide emissions and different climate, soil chemistry and N-deposition data. It was found that changes in soil moisture and soil temperature significantly effected CO2 and N-oxide emissions with a time lag of up to two weeks and could explain up to 95% of the temporal variations of gas emissions. Event emissions after rain or during freezing and thawing cycles contributed significantly (for NO 50% to overall N-oxides emissions. In the two-year period of analysis the annual gaseous N2O losses at SW ranged from 0.65 to 0.77 kg N ha-1 y-1 and NO losses were 0.18 to 0.67 kg N ha-1 per vegetation period. In KL significantly lower annual N2O emissions (0.52 kg N2O-N kg ha-1 y-1 as well as considerably lower NO-losses were observed. During a three-month measurement campaign NO losses at KL were 0.02 kg, whereas in the same time period significantly more NO was emitted in SW (0.32 kg NO-N ha-1. Higher N-oxide emissions, especially NO emissions from the high N-input site (SW indicate that atmospheric

  3. Searching informed game trees

    NARCIS (Netherlands)

    W.H.L.M. Pijls (Wim); A. de Bruin (Arie)

    1992-01-01

    textabstractWell-known algorithms for the evaluation of the minimax function in game trees are alpha-beta and SSS*. An improved version of SSS* is SSS-2. All these algorithms don't use any heuristic information on the game tree. In this paper the use of heuristic information is introduced into the a

  4. Structural Equation Model Trees

    Science.gov (United States)

    Brandmaier, Andreas M.; von Oertzen, Timo; McArdle, John J.; Lindenberger, Ulman

    2013-01-01

    In the behavioral and social sciences, structural equation models (SEMs) have become widely accepted as a modeling tool for the relation between latent and observed variables. SEMs can be seen as a unification of several multivariate analysis techniques. SEM Trees combine the strengths of SEMs and the decision tree paradigm by building tree…

  5. Matching Subsequences in Trees

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li

    2009-01-01

    Given two rooted, labeled trees P and T the tree path subsequence problem is to determine which paths in P are subsequences of which paths in T. Here a path begins at the root and ends at a leaf. In this paper we propose this problem as a useful query primitive for XML data, and provide new...

  6. Pruning peach trees

    OpenAIRE

    Sagers, Larry A.

    1988-01-01

    Discusses the importance of annual pruning to produce high yield and quality of peaches. Advises that the successful pruner should understand how the trees grow, and how the trees respond to pruning. Also cautions that improper pruning will lower yield and quality of fruit.

  7. Tree nut oils

    Science.gov (United States)

    The major tree nuts include almonds, Brazil nuts, cashew nuts, hazelnuts, macadamia nuts, pecans, pine nuts, pistachio nuts, and walnuts. Tree nut oils are appreciated in food applications because of their flavors and are generally more expensive than other gourmet oils. Research during the last de...

  8. Mineralisation, leaching and stabilisation of 13C-labelled leaf and twig litter in a beech forest soil

    Directory of Open Access Journals (Sweden)

    F. Hagedorn

    2011-02-01

    Full Text Available Very few field studies have quantified the different pathways of C loss from decomposing litter even though this is essential to better understand long-term dynamics of C stocks in soils. Using 13C-labelled leaf (isotope ratio (δ13C = −40.8‰ and twig litter (δ13C = −38.4‰, we tracked down the litter-derived C in the soil respiration, in the dissolved organic C (DOC and in the soil organic matter of a beech forest in the Swiss Jura. After one year of decomposition, mass loss in the litter layer was almost twice as great for leaves as it was for twigs (75% vs. 40%. This difference was not the result of a slow mineralisation of the woody litter, but primarily of the only slight incorporation of twig-derived C into mineral soils. The C mineralisation rates of the twig litter were only slightly lower than those of the leaf litter (10–35%, in particular after the loss of the readily available litter fraction. However, the leaching of DOC from twigs amounted only to half of that from leaves. Tracing the litter-derived DOC showed that DOC from both litter types was mostly retained (88–96% and stabilised in the top centimetres of the mineral soil. In the soil organic C at 0–2 cm depth, we recovered 8% of the initial leaf C, but only 4% of the twig C. Moreover, the 13C mass balance suggested that a substantial fraction of the leaf material (~30% was transported via soil fauna to soil depths below 2 cm, while the twig litter mainly decomposed in situ on the soil surface, probably due to its rigid structure and low nutritional value. In summary, our study shows that decaying twigs are rapidly mineralised, but seem to be clearly less important for the C storage in this beech forest soils than leaf litter.

  9. Distribution model of understory vegetation in beech forests from Central Apennines (Italy in relation to edaphic parameters

    Directory of Open Access Journals (Sweden)

    De Nicola C

    2007-12-01

    Full Text Available The first results of a study of monitoring species and habitats in the framework of the Life 04NAT/IT/000190 "Tutela dei siti Natura 2000 gestiti dal Corpo Forestale dello Stato" are presented. This study was carried out by the Department of Plant Biology of the University of Rome (La Sapienza and the National Forest Service. We focused the investigation on the relationships between herbaceous species and pedological parameters (humus and soil in Central-Apennine beech forests. Data have been collected through 40 phytosociological relevés, 15 soil profiles and 40 humus profiles in 40 forest plots, between March 2005 and September 2006. In this paper we presented data elaborated on a subset of 15 plots where soil profiles were available. The species of undergrowth showed different ecological requirements to some edaphic and humus parameters (pH, sand, loam, clay, organic matter, nitrogen, carbon/nitrogen ratio, Ca++, K+;thickness and carbon content of the organic layers: significant correlations have been found using Pearson correlation test. The multiple regression analysis allowed to identify the factors more influencing the species distribution: thickness of the organic layers, carbon content (% C and carbon/nitrogen ratio (C/N. Basing on the thickness of humus horizons (OL, OF, OH, and on carbon content, two species groups with different ecology have been recognized: (a nemoral species typical of shady beech stands on oligomull/dysmull/thin amphimull (0 < 1cm.; 5.7 < %C < 9.9; (b heliophilous species of more xeric stands on thick amphimull (1.25 < 11.5 cm.; 9.9 < %C < 13.7. The relationships among species and soil parameters and humus forms allow to recognize small differences within a homogeneous habitat and therefore they can provide management indications also at micro-scale level.

  10. PaisleyTrees: A Size-Invariant Tree Visualization

    Directory of Open Access Journals (Sweden)

    Katayoon Etemad

    2014-10-01

    Full Text Available Squeezing large tree structures into suitable visualizations has been a perennial problem. In response to this challenge, we present PaisleyTrees, a size-invariant tree visualization. PaisleyTrees integrate node-of-interest focus with tree-cut presentations to support rapid tree navigation without resorting to zooming and panning. This visualization offers the ability to work with trees of arbitrary depth and breadth, and maintains legibility for displayed elements. These advantages are achieved by using a hybrid layout, inspired by traditional Paisley patterns, that combines node-link, nested and djacency-based tree layout techniques, and offers both depth and breadth elision.

  11. Significance of tree roots for preferential infiltration in stagnic soils

    Directory of Open Access Journals (Sweden)

    B. Lange

    2009-10-01

    Full Text Available It is generally recognized that roots have an effect on infiltration. In this study we analysed the relation between root length distributions from Norway spruce (Picea abies (L. Karst, silver fir (Abies alba Miller, European beech (Fagus sylvatica L. and preferential infiltration in stagnic soils in the northern Pre-Alps in Switzerland. We conducted irrigation experiments (1 m2 and recorded water content variations with time domain reflectometry (TDR. A rivulet approach was applied to characterise preferential infiltration. Roots were sampled down to a depth of 0.5 to 1 m at the same position where the TDR-probes had been inserted and digitally measured. The basic properties of preferential infiltration, film thickness of mobile water and the contact length between soil and mobile water in the horizontal plane are closely related to root densities. An increase in root density resulted in an increase in contact length, but a decrease in film thickness. We modelled water content waves based on root densities and identified a range of root densities that lead to a maximum volume flux density and infiltration capacity. These findings provide convincing evidence that tree roots in stagnic soils represent the pore system that carries preferential infiltration. Thus, the presence of roots should improve infiltration.

  12. Changes of soil conditions and floristic composition in Black Pine forest (Fraxino orni-Pinetum nigrae) and in the forest of beech and Hairy Alpenrose (Rhododendro hirsuti-Fagetum) after the wildfire

    OpenAIRE

    Urbančič, Mihej; Dakskobler, Igor

    2001-01-01

    We studied soil conditions and floristic comsposition in the forest of beech and Hairy Alpenrose (Rhododendro hirsuti-Fagetum) and in the south-Alpine Austrian black pine forest (Fraxino orni-Pinetum nigrae) within the area of the forest fire in Govci (which is located in the northwestern edge of the Trnovski gozd plateau, western Slovenia) and compared them with conditions in preserved beech and black pine forests five years after the wildfire. The black pine forest overgrows Lithosols and M...

  13. Skewed Binary Search Trees

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Moruz, Gabriel

    2006-01-01

    It is well-known that to minimize the number of comparisons a binary search tree should be perfectly balanced. Previous work has shown that a dominating factor over the running time for a search is the number of cache faults performed, and that an appropriate memory layout of a binary search tree...... can reduce the number of cache faults by several hundred percent. Motivated by the fact that during a search branching to the left or right at a node does not necessarily have the same cost, e.g. because of branch prediction schemes, we in this paper study the class of skewed binary search trees....... For all nodes in a skewed binary search tree the ratio between the size of the left subtree and the size of the tree is a fixed constant (a ratio of 1/2 gives perfect balanced trees). In this paper we present an experimental study of various memory layouts of static skewed binary search trees, where each...

  14. Phylogenetic trees in bioinformatics

    Energy Technology Data Exchange (ETDEWEB)

    Burr, Tom L [Los Alamos National Laboratory

    2008-01-01

    Genetic data is often used to infer evolutionary relationships among a collection of viruses, bacteria, animal or plant species, or other operational taxonomic units (OTU). A phylogenetic tree depicts such relationships and provides a visual representation of the estimated branching order of the OTUs. Tree estimation is unique for several reasons, including: the types of data used to represent each OTU; the use ofprobabilistic nucleotide substitution models; the inference goals involving both tree topology and branch length, and the huge number of possible trees for a given sample of a very modest number of OTUs, which implies that fmding the best tree(s) to describe the genetic data for each OTU is computationally demanding. Bioinformatics is too large a field to review here. We focus on that aspect of bioinformatics that includes study of similarities in genetic data from multiple OTUs. Although research questions are diverse, a common underlying challenge is to estimate the evolutionary history of the OTUs. Therefore, this paper reviews the role of phylogenetic tree estimation in bioinformatics, available methods and software, and identifies areas for additional research and development.

  15. Compatible spanning trees

    OpenAIRE

    Garcia Olaverri, Alfredo Martin; Huemer, Clemens; Hurtado Díaz, Fernando Alfredo; Tejel Altarriba, Francisco Javier

    2014-01-01

    Two plane geometric graphs are said to be compatible when their union is a plane geometric graph. Let S be a set of n points in the Euclidean plane in general position and let T be any given plane geometric spanning tree of S. In this work, we study the problem of finding a second plane geometric tree T' spanning S, such that is compatible with T and shares the minimum number of edges with T. We prove that there is always a compatible plane geometric tree T' having at most #n - 3#/4 edges in ...

  16. LIMSUP DEVIATIONS ON TREES

    Institute of Scientific and Technical Information of China (English)

    Fan Aihua

    2004-01-01

    The vertices of an infinite locally finite tree T are labelled by a collection of i.i.d. real random variables {Xσ}σ∈T which defines a tree indexed walk Sσ = ∑θ<r≤σXr. We introduce and study the oscillations of the walk:Exact Hausdorff dimension of the set of such ξ 's is calculated. An application is given to study the local variation of Brownian motion. A general limsup deviation problem on trees is also studied.

  17. The gravity apple tree

    Science.gov (United States)

    Espinosa Aldama, Mariana

    2015-04-01

    The gravity apple tree is a genealogical tree of the gravitation theories developed during the past century. The graphic representation is full of information such as guides in heuristic principles, names of main proponents, dates and references for original articles (See under Supplementary Data for the graphic representation). This visual presentation and its particular classification allows a quick synthetic view for a plurality of theories, many of them well validated in the Solar System domain. Its diachronic structure organizes information in a shape of a tree following similarities through a formal concept analysis. It can be used for educational purposes or as a tool for philosophical discussion.

  18. Creating 13C- and 15N-enriched tree leaf litter for decomposition experiments

    Science.gov (United States)

    Szlavecz, K. A.; Pitz, S.; Chang, C.; Bernard, M.

    2013-12-01

    Labeling plant material with heavy isotopes of carbon and nitrogen can produce a traceable nutrient signal that can be followed into the different trophic levels and decomposer food web. We treated 60 tree saplings with 13C-enriched CO2 gas and 15N-enriched ammonium nitrate over a three-month period to create dually-labeled plant material for future decomposition experiments. The trees included both early (Red maple, Sweetgum, Tulip poplar) and late (American beech, White oak) successional deciduous tree species, and a conifer, White pine. We constructed a 2.4 m × 2.4 m × 2.4 m environmental chamber that was climate-controlled using an air conditioning system. An Arduino microcontroller interfaced with a Vaisala GMP343 CO2 probe maintained a CO2 concentration between 500-520 ppm by controlling a solenoid valve on the CO2 tank regulator. The trees were placed into the chamber in August 2012 and remained until senescence unless they were lost to death or disease. Ammonium nitrate was added twice, in September and October. Leaf samples were collected prior to the start of the experiment and after senescence, whereas root samples were collected only in December. Samples were dried, ground and analyzed using an isotope ratio mass spectrometer. American beech and White oak had 40% mortality, and 34% of tulip poplar trees were removed because of powdery mildew overgrowth or death. Most tulip poplar trees exhibited a second leaf out following senescence in late September. Nearly 1 kg of litter was produced with tulip poplar representing over half of the total mass. Levels of enrichment varied greatly by species. Beech (-14.2‰) and White oak (-4.8‰) had low levels of enrichment in comparison to early successional species such as Sweetgum (41.7‰) and Tulip poplar (30.7‰ [first leaf fall] and 238.0‰ [second leaf fall]). Leaf enrichment with 15N followed a similar pattern, though it was achieved at a higher level with δ15N values varying from 271.6‰ to 1354.2

  19. Long-term growth trajectories in a changing climate: disentangling age from size effects in old Fagus trees from contrasting bioclimates

    Science.gov (United States)

    Di Filippo, Alfredo; Piovesan, Gianluca

    2016-04-01

    Understanding the drivers promoting exceptional longevity in trees and how their growth performances vary approaching maximum lifespan still represent intriguing challenges not only for tree biology, but also for modelling the long-term forest ecosystem functioning under a changing environment. Tree growth rate is expected to increase with increasing stem size, but higher risk of hydraulic failure and mortality can affect larger trees under increasingly dry conditions. In turn, very old trees are characterized by slow growth and smaller size, factors able to confer advantages against biotic and abiotic disturbances. Rising evidences that very old trees are negligibly affected by the progressive deterioration of physiological functions associated with age support the idea that size, not age, is the main constrain to tree lifespan, so that negative senescence has been proposed as a frequent phenomenon in trees. Additional empirical knowledge is needed to thoroughly assess how complex, uneven-aged old-growth forests cope under climate change in order to define their role in terrestrial carbon cycle. We used a tree-ring network of 8 European beech (Fagus sylvatica L.) old-growth forests containing several of the oldest crossdated broadleaf trees of the Northern Hemisphere (400-600 years old) to analyse how their growth rates vary along age/size development. We sampled advanced old-growth stands, where canopy tree mortality is naturally occurring, divided among contrasting bioclimatic conditions: eastern Alps and central Apennines (rainy vs. dry summer). To disentangle the long-term effects of size and age on long-term tree growth history, we reconstructed Basal Area Increment (BAI) along size (DBH) development, grouping growth trajectories in different age classes. On average, BAI increased continuously as stem size increased, regardless of bioclimatic region and age class. Old trees grew the slowest and kept increasing BAI trends. In turn, especially on the drier

  20. Depth distribution and composition of seed banks under different tree layers in a managed temperate forest ecosystem

    Science.gov (United States)

    Godefroid, Sandrine; Phartyal, Shyam S.; Koedam, Nico

    2006-05-01

    In the present work we examined the composition and distribution across three soil layers of the buried soil seed bank under three different overstory types ( Fagus sylvatica, Quercus robur, Pinus sylvestris) and in logging areas in a 4383-ha forest in central Belgium. The objectives were: (1) to investigate whether species composition and species richness of soil seed banks are affected by different forest stands; (2) to examine how abundant are habitat-specific forest species in seed banks under different planted tree layers. The study was carried out in stands which are replicated, managed in the same way (even-aged high forest), and growing on the same soil type with the same land-use history. In the investigated area, the seed bank did show significant differences under oak, beech, pine and in logging areas, respectively in terms of size, composition and depth occurrence. All species and layers taken together, the seed bank size ranked as follows: oakwood > beechwood > logging area > pinewood. The same pattern was found for forest species. Seed numbers of Betula pendula, Calluna vulgaris, Dryopteris dilatata and Rubus fruticosus were significantly higher under the beech canopy. Carex remota, Impatiens parviflora and Lotus sp. showed a significantly denser seed bank in logging areas, while Digitalis purpurea seeds were significantly more abundant in soils under the oak canopy. The fact that the seed bank of an originally homogeneous forest varies under different planted stands highlights that a long period of canopy conversion can affect the composition and depth of buried seeds.

  1. Tree-growth analyses to estimate tree species' drought tolerance

    NARCIS (Netherlands)

    Eilmann, B.; Rigling, A.

    2012-01-01

    Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree specie

  2. A Characterization of the average tree solution for tree games

    OpenAIRE

    Debasis Mishra; Dolf Talman

    2009-01-01

    For the class of tree games, a new solution called the average tree solution has been proposed recently. We provide a characterization of this solution. This characterization underlines an important difference, in terms of symmetric treatment of the agents, between the average tree solution and the Myerson value for the class of tree games.

  3. ControlTree: Navigating and Selecting in a Large Tree

    OpenAIRE

    Appert, Caroline; Fekete, Jean-Daniel

    2006-01-01

    International audience We introduce ControlTree, a novel interface using crossing interaction to navigate and select nodes in a large tree. ControlTree combines an optimized dynamic layout with interaction features to quickly reach a node in a node-link tree representation.

  4. Tree-like tableaux

    CERN Document Server

    Aval, Jean-Christophe; Nadeau, Philippe

    2011-01-01

    In this work we introduce and study tree-like tableaux, which are certain fillings of Ferrers diagrams in simple bijection with permutation tableaux and alternative tableaux. We exhibit an elementary insertion procedure on our tableaux which gives a clear proof that tableaux of size n are counted by n!, and which moreover respects most of the well-known statistics studied originally on alternative and permutation tableaux. Our insertion procedure allows to define in particular two simple new bijections between tree-like tableaux and permutations: the first one is conceived specifically to respect the generalized pattern 2-31, while the second one respects the underlying tree of a tree-like tableau.

  5. The tree BVOC index.

    Science.gov (United States)

    Simpson, J R; McPherson, E G

    2011-01-01

    Urban trees can produce a number of benefits, among them improved air quality. Biogenic volatile organic compounds (BVOCs) emitted by some species are ozone precursors. Modifying future tree planting to favor lower-emitting species can reduce these emissions and aid air management districts in meeting federally mandated emissions reductions for these compounds. Changes in BVOC emissions are calculated as the result of transitioning to a lower-emitting species mix in future planting. A simplified method for calculating the emissions reduction and a Tree BVOC index based on the calculated reduction is described. An example illustrates the use of the index as a tool for implementation and monitoring of a tree program designed to reduce BVOC emissions as a control measure being developed as part of the State Implementation Plan (SIP) for the Sacramento Federal Nonattainment Area. PMID:21435760

  6. Loops and trees

    Science.gov (United States)

    Caron-Huot, S.

    2011-05-01

    We investigate relations between loop and tree amplitudes in quantum field theory that involve putting on-shell some loop propagators. This generalizes the so-called Feynman tree theorem which is satisfied at 1-loop. Exploiting retarded boundary conditions, we give a generalization to ℓ-loop expressing the loops as integrals over the on-shell phase space of exactly ℓ particles. We argue that the corresponding integrand for ℓ > 2 does not involve the forward limit of any physical tree amplitude, except in planar gauge theories. In that case we explicitly construct the relevant physical amplitude. Beyond the planar limit, abandoning direct integral representations, we propose that loops continue to be determined implicitly by the forward limit of physical connected trees, and we formulate a precise conjecture along this line. Finally, we set up technology to compute forward amplitudes in supersymmetric theories, in which specific simplifications occur.

  7. A parallel buffer tree

    DEFF Research Database (Denmark)

    Sitchinava, Nodar; Zeh, Norbert

    2012-01-01

    We present the parallel buffer tree, a parallel external memory (PEM) data structure for batched search problems. This data structure is a non-trivial extension of Arge's sequential buffer tree to a private-cache multiprocessor environment and reduces the number of I/O operations by the number...... of available processor cores compared to its sequential counterpart, thereby taking full advantage of multicore parallelism. The parallel buffer tree is a search tree data structure that supports the batched parallel processing of a sequence of N insertions, deletions, membership queries, and range queries...... in the optimal OhOf(psortN + K/PB) parallel I/O complexity, where K is the size of the output reported in the process and psortN is the parallel I/O complexity of sorting N elements using P processors....

  8. NLCD 2001 - Tree Canopy

    Data.gov (United States)

    Minnesota Department of Natural Resources — The National Land Cover Database 2001 tree canopy layer for Minnesota (mapping zones 39-42, 50-51) was produced through a cooperative project conducted by the...

  9. Robustness of a routing tree for the Push Tree Problem

    OpenAIRE

    Havet, Frédéric

    2002-01-01

    The Push Tree problem contains elements from both the Steiner Tree and Shortest Path problem. It deals with the trade-offs between the push and pull mechanism used in information distribution and retrieval. In , a two step approach for the Push Tree Problem was proposed. In the first step, a «good» spanning tree (called routing tree) is constructed and then the problem is solved in this particular tree. Finding a routing tree is NP-hard but the second step may be performed easily, thus the id...

  10. Type extension trees

    DEFF Research Database (Denmark)

    Jaeger, Manfred

    2006-01-01

    We introduce type extension trees as a formal representation language for complex combinatorial features of relational data. Based on a very simple syntax this language provides a unified framework for expressing features as diverse as embedded subgraphs on the one hand, and marginal counts...... of attribute values on the other. We show by various examples how many existing relational data mining techniques can be expressed as the problem of constructing a type extension tree and a discriminant function....

  11. Information flow on trees

    OpenAIRE

    Mossel, Elchanan; Peres, Yuval

    2003-01-01

    Consider a tree network $T$, where each edge acts as an independent copy of a given channel $M$, and information is propagated from the root. For which $T$ and $M$ does the configuration obtained at level $n$ of $T$ typically contain significant information on the root variable? This problem arose independently in biology, information theory and statistical physics. ¶ For all $b$, we construct a channel for which the variable at the root of the break $b$-ary tree is...

  12. Urban tree mortality

    OpenAIRE

    Roman, Lara Angelica

    2013-01-01

    Urban forests have aesthetic, environmental, human health, and economic benefits that motivate tree planting programs. Realizing these benefits depends on tree survival. Cost-benefit analyses for urban forest ecosystem services are sensitive to mortality rate assumptions and associated population projections. However, long-term mortality data is needed to assess the accuracy of these assumptions. Analytical tools from demography, such as life tables, mortality curves, and survival analysis, c...

  13. Tree Improvement Glossary

    DEFF Research Database (Denmark)

    Schmidt, Lars Holger

    Forest tree improvement encompasses a number of scientific and technical areas like floral-, reproductive- and micro-biology, genetics breeding methods and strategies, propagation, gene conservation, data analysis and statistics, each area with a comprehensive terminology. The terms selected...... for definition here are those most frequently used in tree improvement literature. Clonal propagation is included in the view of the great expansion of that field as a means of mass multiplication of improved material....

  14. Tree felling 2014

    CERN Multimedia

    2014-01-01

    With a view to creating new landscapes and making its population of trees safer and healthier, this winter CERN will complete the tree-felling campaign started in 2010.   Tree felling will take place between 15 and 22 November on the Swiss part of the Meyrin site. This work is being carried out above all for safety reasons. The trees to be cut down are at risk of falling as they are too old and too tall to withstand the wind. In addition, the roots of poplar trees are very powerful and spread widely, potentially damaging underground networks, pavements and roadways. Compensatory tree planting campaigns will take place in the future, subject to the availability of funding, with the aim of creating coherent landscapes while also respecting the functional constraints of the site. These matters are being considered in close collaboration with the Geneva nature and countryside directorate (Direction générale de la nature et du paysage, DGNP). GS-SE Group

  15. Geometric Decision Tree

    CERN Document Server

    Manwani, Naresh

    2010-01-01

    In this paper we present a new algorithm for learning oblique decision trees. Most of the current decision tree algorithms rely on impurity measures to assess the goodness of hyperplanes at each node while learning a decision tree in a top-down fashion. These impurity measures do not properly capture the geometric structures in the data. Motivated by this, our algorithm uses a strategy to assess the hyperplanes in such a way that the geometric structure in the data is taken into account. At each node of the decision tree, we find the clustering hyperplanes for both the classes and use their angle bisectors as the split rule at that node. We show through empirical studies that this idea leads to small decision trees and better performance. We also present some analysis to show that the angle bisectors of clustering hyperplanes that we use as the split rules at each node, are solutions of an interesting optimization problem and hence argue that this is a principled method of learning a decision tree.

  16. Microbial processes and community composition in the rhizosphere of European beech – The influence of plant C exudates

    OpenAIRE

    Koranda, Marianne; Schnecker, Jörg; Kaiser, Christina; Fuchslueger, Lucia; Kitzler, Barbara; Stange, Claus Florian; Sessitsch, Angela; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2011-01-01

    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 ro...

  17. Tipi ektomikorize pri sadikah bukve (Fagus sylvatica L.) v rizotronih: Types of ectomycorrhizae on beech seedlings (Fagus sylvatica L.) in rhizotrons:

    OpenAIRE

    Bajc, Marko; Grebenc, Tine; Kraigher, Hojka; Mali, Boštjan; Štraus, Ines

    2011-01-01

    Natural processes or human activities affect environmental conditions, as reflected in the structure of the communities and the level of ectomycorrhizalfungi. The aim of the study was to determine the potential impacts of several temperature regimes of air and soil (substrate) on the occurrence and species diversity of ectomycorrhizal fungi in symbiosis and in the substrate. For this purpose, we analyzed the occurrence of types of ectomycorrhizae on beech seedlings in rhizotrons exposed to fo...

  18. Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3.

    Science.gov (United States)

    Kitao, Mitsutoshi; Yasuda, Yukio; Kominami, Yuji; Yamanoi, Katsumi; Komatsu, Masabumi; Miyama, Takafumi; Mizoguchi, Yasuko; Kitaoka, Satoshi; Yazaki, Kenichi; Tobita, Hiroyuki; Yoshimura, Kenichi; Koike, Takayoshi; Izuta, Takeshi

    2016-01-01

    Ground-level ozone (O3) concentrations are expected to increase over the 21(st) century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive Japanese beech (Fagus crenata), and in a warm temperate deciduous and evergreen forest dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations. On the basis of a practical approach for a continuous estimation of canopy-level stomatal conductance (Gs), higher phytotoxic ozone dose above a threshold of 0 uptake (POD0) with higher Gs was observed in the beech forest than that in the oak forest. Light-saturated gross primary production, as a measure of carbon sequestration capacity of forest ecosystem, declined earlier in the late growth season with increasing POD0, suggesting an earlier autumn senescence, especially in the O3-sensitive beech forest, but not in the O3-tolerant oak forest. PMID:27601188

  19. Effects of the distribution, amount, and size of beech fine roots on the C-turnover in the topsoil and subsoil of a sandy podzolic Cambisol

    Science.gov (United States)

    Vormstein, Svendja; Kaiser, Michael; Ludwig, Bernard

    2015-04-01

    The function of soil to act as a sink for CO2 is affected by the decomposition intensity of plant roots entering the mineral soil at different depths. Little is known about the key factors governing the mineralization kinetics of beech fine roots in different soil depths. We aimed to analyze the effects of the distribution, amount, and size of beech fine roots on their decomposition in the top- and subsoil. Topsoil (2 - 10 cm) and subsoil (145 - 152 cm) samples were taken from 3 profiles of a sandy Cambisol under beech located near Hannover (Germany). Incubation experiments were carried out for 300 days at 10°C and water contents at 50% of the water-holding capacity and CO2 emission rates were determined using an automated microcosm system. Treatments included control soils (either homogenized and sieved received the 1-2 cm roots compared to those containing the account for the elucidation of differences in the decomposition kinetics of roots between topsoil and subsoil.

  20. Effect of the silvicultural treatment on canopy properties, litter and seed production in beech coppices under conversion to high forest.

    Directory of Open Access Journals (Sweden)

    Andrea Cutini

    2010-12-01

    Full Text Available European beech (Fagus sylvatica L. is widely distributed in Italy where it covers 1035103 ha, mainly concentrated in the mountainous areas at altitudes above 900 m. The major part is represented by high forest often issued from the conversion of coppice woods, which in the past was the silvicultural system most widely applied mainly to provide fire wood. The social changes occurred in the second half of the last century –fire wood market crisis and the increasing importance of environmental issues- enhanced the conversion into high forest of large areas previously managed as coppice by means of different silvicultural treatments and practices. Nevertheless, the environmental benefits of this choice were not adequately investigated. Results of annual measurements (1992-2009 made in a beech coppice stand aged 65 are here reported. The study area is located on the Alpe di Catenaia, a pre-Apennine outcrop close to Arezzo (Central Italy. Variables strictly related to stand productivity and dynamics such as annual litter and seed production, leaf area index (LAI and transmittance (PAR were measured in the research area of Buca Zamponi to estimate the effects of two theses, natural evolution (TEST and conversion into high forest (DIR. Three thinnings were undertaken in the latter thesis in 1972, 1987 and 2002. Additional theses of natural evolution (CONTR and advance seed cutting (TS were added in 2002 in a nearby study area (Eremo della Casella. Results showed the high productivity of coppice stands, under conversion to high forest, with mean values of annual total litter, leaf litter and leaf area index of 5 Mg ha-1, 3 Mg ha-1 and 6 m2m-2, respectively. These findings confirm both the prompt response of beech to intensive thinning cycles and the reliability of undertaking coppice conversion into high forest. Furthermore, the positive trend observed in the ecological parameters and the high consistency of leaf fraction, highlight the still juvenile

  1. Variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species.

    Science.gov (United States)

    Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

    2008-12-01

    Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter. In all investigated species except the diffuse-porous beech (Fagus sylvatica L.) and ring-porous ash (Fraxinus excelsior L.), sap flux density peaked at a depth of 1 to 4 cm beneath the cambium, revealing a hump-shaped curve with species-specific slopes. Beech and ash reached maximum sap flux densities immediately beneath the cambium in the youngest annual growth rings. Experiments with dyes showed that the hydro-active sapwood occupied 70 to 90% of the stem cross-sectional area in mature trees of diffuse-porous species, whereas it occupied only about 21% in ring-porous ash. Dendrochronological analyses indicated that vessels in the older sapwood may remain functional for 100 years or more in diffuse-porous species and for up to 27 years in ring-porous ash. We conclude that radial sap flux density patterns are largely dependent on tree species, which may introduce serious bias in sap-flux-derived forest transpiration estimates, if non-specific sap flux profiles are assumed.

  2. Covering R-trees

    CERN Document Server

    Berestovskii, V N

    2007-01-01

    We show that every inner metric space X is the metric quotient of a complete R-tree via a free isometric action, which we call the covering R-tree of X. The quotient mapping is a weak submetry (hence, open) and light. In the case of compact 1-dimensional geodesic space X, the free isometric action is via a subgroup of the fundamental group of X. In particular, the Sierpin'ski gasket and carpet, and the Menger sponge all have the same covering R-tree, which is complete and has at each point valency equal to the continuum. This latter R-tree is of particular interest because it is "universal" in at least two senses: First, every R-tree of valency at most the continuum can be isometrically embedded in it. Second, every Peano continuum is the image of it via an open light mapping. We provide a sketch of our previous construction of the uniform universal cover in the special case of inner metric spaces, the properties of which are used in the proof.

  3. Steiner trees in industry

    CERN Document Server

    Du, Ding-Zhu

    2001-01-01

    This book is a collection of articles studying various Steiner tree prob­ lems with applications in industries, such as the design of electronic cir­ cuits, computer networking, telecommunication, and perfect phylogeny. The Steiner tree problem was initiated in the Euclidean plane. Given a set of points in the Euclidean plane, the shortest network interconnect­ ing the points in the set is called the Steiner minimum tree. The Steiner minimum tree may contain some vertices which are not the given points. Those vertices are called Steiner points while the given points are called terminals. The shortest network for three terminals was first studied by Fermat (1601-1665). Fermat proposed the problem of finding a point to minimize the total distance from it to three terminals in the Euclidean plane. The direct generalization is to find a point to minimize the total distance from it to n terminals, which is still called the Fermat problem today. The Steiner minimum tree problem is an indirect generalization. Sch...

  4. The inference of gene trees with species trees.

    Science.gov (United States)

    Szöllősi, Gergely J; Tannier, Eric; Daubin, Vincent; Boussau, Bastien

    2015-01-01

    This article reviews the various models that have been used to describe the relationships between gene trees and species trees. Molecular phylogeny has focused mainly on improving models for the reconstruction of gene trees based on sequence alignments. Yet, most phylogeneticists seek to reveal the history of species. Although the histories of genes and species are tightly linked, they are seldom identical, because genes duplicate, are lost or horizontally transferred, and because alleles can coexist in populations for periods that may span several speciation events. Building models describing the relationship between gene and species trees can thus improve the reconstruction of gene trees when a species tree is known, and vice versa. Several approaches have been proposed to solve the problem in one direction or the other, but in general neither gene trees nor species trees are known. Only a few studies have attempted to jointly infer gene trees and species trees. These models account for gene duplication and loss, transfer or incomplete lineage sorting. Some of them consider several types of events together, but none exists currently that considers the full repertoire of processes that generate gene trees along the species tree. Simulations as well as empirical studies on genomic data show that combining gene tree-species tree models with models of sequence evolution improves gene tree reconstruction. In turn, these better gene trees provide a more reliable basis for studying genome evolution or reconstructing ancestral chromosomes and ancestral gene sequences. We predict that gene tree-species tree methods that can deal with genomic data sets will be instrumental to advancing our understanding of genomic evolution.

  5. Generic Ising trees

    DEFF Research Database (Denmark)

    Durhuus, Bergfinnur Jøgvan; Napolitano, George Maria

    2012-01-01

    The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove that they......The Ising model on a class of infinite random trees is defined as a thermodynamiclimit of finite systems. A detailed description of the corresponding distribution of infinite spin configurations is given. As an application, we study the magnetization properties of such systems and prove...... that they exhibit no spontaneous magnetization. Furthermore, the values of the Hausdorff and spectral dimensions of the underlying trees are calculated and found to be, respectively,¯dh =2 and¯ds = 4/3....

  6. Active flows on trees

    CERN Document Server

    Forrow, Aden; Dunkel, Jörn

    2016-01-01

    Coherent, large scale dynamics in many nonequilibrium physical, biological, or information transport networks are driven by small-scale local energy input. We introduce and explore a generic model for compressible active flows on tree networks. In contrast to thermally-driven systems, active friction selects discrete states with only a small number of oscillation modes activated at distinct fixed amplitudes. This state selection interacts with graph topology to produce different localized dynamical time scales in separate regions of large networks. Using perturbation theory, we systematically predict the stationary states of noisy networks and find good agreement with a Bayesian state estimation based on a hidden Markov model applied to simulated time series data on binary trees. While the number of stable states per tree scales exponentially with the number of edges, the mean number of activated modes in each state averages $\\sim 1/4$ the number of edges. More broadly, these results suggest that the macrosco...

  7. The gene tree delusion.

    Science.gov (United States)

    Springer, Mark S; Gatesy, John

    2016-01-01

    Higher-level relationships among placental mammals are mostly resolved, but several polytomies remain contentious. Song et al. (2012) claimed to have resolved three of these using shortcut coalescence methods (MP-EST, STAR) and further concluded that these methods, which assume no within-locus recombination, are required to unravel deep-level phylogenetic problems that have stymied concatenation. Here, we reanalyze Song et al.'s (2012) data and leverage these re-analyses to explore key issues in systematics including the recombination ratchet, gene tree stoichiometry, the proportion of gene tree incongruence that results from deep coalescence versus other factors, and simulations that compare the performance of coalescence and concatenation methods in species tree estimation. Song et al. (2012) reported an average locus length of 3.1 kb for the 447 protein-coding genes in their phylogenomic dataset, but the true mean length of these loci (start codon to stop codon) is 139.6 kb. Empirical estimates of recombination breakpoints in primates, coupled with consideration of the recombination ratchet, suggest that individual coalescence genes (c-genes) approach ∼12 bp or less for Song et al.'s (2012) dataset, three to four orders of magnitude shorter than the c-genes reported by these authors. This result has general implications for the application of coalescence methods in species tree estimation. We contend that it is illogical to apply coalescence methods to complete protein-coding sequences. Such analyses amalgamate c-genes with different evolutionary histories (i.e., exons separated by >100,000 bp), distort true gene tree stoichiometry that is required for accurate species tree inference, and contradict the central rationale for applying coalescence methods to difficult phylogenetic problems. In addition, Song et al.'s (2012) dataset of 447 genes includes 21 loci with switched taxonomic names, eight duplicated loci, 26 loci with non-homologous sequences that are

  8. The gene tree delusion.

    Science.gov (United States)

    Springer, Mark S; Gatesy, John

    2016-01-01

    Higher-level relationships among placental mammals are mostly resolved, but several polytomies remain contentious. Song et al. (2012) claimed to have resolved three of these using shortcut coalescence methods (MP-EST, STAR) and further concluded that these methods, which assume no within-locus recombination, are required to unravel deep-level phylogenetic problems that have stymied concatenation. Here, we reanalyze Song et al.'s (2012) data and leverage these re-analyses to explore key issues in systematics including the recombination ratchet, gene tree stoichiometry, the proportion of gene tree incongruence that results from deep coalescence versus other factors, and simulations that compare the performance of coalescence and concatenation methods in species tree estimation. Song et al. (2012) reported an average locus length of 3.1 kb for the 447 protein-coding genes in their phylogenomic dataset, but the true mean length of these loci (start codon to stop codon) is 139.6 kb. Empirical estimates of recombination breakpoints in primates, coupled with consideration of the recombination ratchet, suggest that individual coalescence genes (c-genes) approach ∼12 bp or less for Song et al.'s (2012) dataset, three to four orders of magnitude shorter than the c-genes reported by these authors. This result has general implications for the application of coalescence methods in species tree estimation. We contend that it is illogical to apply coalescence methods to complete protein-coding sequences. Such analyses amalgamate c-genes with different evolutionary histories (i.e., exons separated by >100,000 bp), distort true gene tree stoichiometry that is required for accurate species tree inference, and contradict the central rationale for applying coalescence methods to difficult phylogenetic problems. In addition, Song et al.'s (2012) dataset of 447 genes includes 21 loci with switched taxonomic names, eight duplicated loci, 26 loci with non-homologous sequences that are

  9. Increasing net CO2 uptake by a Danish beech forest during the period from 1996 to 2009

    DEFF Research Database (Denmark)

    Pilegaard, Kim; Ibrom, Andreas; Courtney, Michael;

    2011-01-01

    The exchange of CO2 between the atmosphere and a beech forest near Sorø, Denmark, was measured continuously over 14 years (1996–2009). The simultaneous measurement of many parameters that influence CO2 uptake makes it possible to relate the CO2 exchange to recent changes in e.g. temperature...... in GEE. The overall trend in NEE was significant with an average increase in uptake of 23 g C m−2 yr−2. The carbon uptake period (i.e. the period with daily net CO2 gain) increased by 1.9 days per year, whereas there was a non significant tendency of increase of the leafed period. This means...... that the leaves stayed active longer. The analysis of CO2 uptake by the forest by use of light response curves, revealed that the maximum rate of photosynthetic assimilation increased by 15% during the 14-year period. We conclude that the increase in the overall CO2 uptake of the forest is due to a combination...

  10. Effects of lead and cadmium on the growth and cation contents of beech seedlings on forest soils

    International Nuclear Information System (INIS)

    The influence of lead and cadmium on the growth and Ca, K and Mg contents of beech seedlings (Fagus sylvatica L.) was investigated. The seedlings were cultivated for three months on mineral soil of pH = 3.6 that was treated with various concentrations of either lead or cadmium or combinations of both. Growth was significantly reduced by levels of 280 ppm plant-available Pb and 5 ppm Cd in soil. The reduction in growth seems to be synergistically affected by the treatment with the heavy metals. Cd decreased the contents of Ca and Mg in the plants while the concentration of K was not affected. Among other things there are two reasons discussed for this decrease: (I) the competition of Cd with Ca and Mg in uptake and translocation; (II) an inhibiting effect of Cd on transpiration. The addition of Pb to the Cd-treated plants weakened the influence of Cd on the Ca and Mg concentrations of the seedlings. (orig.)

  11. Penetration of urea-formaldehyde adhesives in wood tissue, part I: Radial penetration of UF adhesives into beech

    Directory of Open Access Journals (Sweden)

    Gavrilović-Grmuša Ivana

    2008-01-01

    Full Text Available Adhesive penetration plays an important role in wood adhesion, since wood is a porous material. The degree of penetration mostly depends on the wood factors, resin type and formulation and processing parameters. Tangentially cut 5 mm thick beech wood (Fagus moesiaca plies, 100 mm long (parallel to grain and 30 mm wide, were prepared for this study. The urea-formaldehyde (UF adhesive was applied to the surface of one ply. Two plies were assembled into sample so that the grains of two plies were parallel. Samples were pressed in a hydraulic press at 120°C and 0,7 MPa for 15 min. Microtome test-specimens were cut of each sample. 20 μm thick microtomes were cut by sliding microtome apparatus, exposing a bondline with a cross-sectional surface. The lack of more exhausting research on the penetration of urea-formaldehyde adhesives in wood is evident. Since ureaformaldehyde (UF glue resins were the most important type of adhesives in the wood industry in the last 60 years (Dunky, 2000, the objective of this research was microscopic detection of UF adhesive penetration in wood tissue. Four types of UF resins with different levels of polycondensation were used in this research. Safranin was added in resins, since epi-fluorescence microscope was used in this research for measuring the adhesive penetration.

  12. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate.

  13. Towards the harmonization between National Forest Inventory and Forest Condition Monitoring. Consistency of plot allocation and effect of tree selection methods on sample statistics in Italy.

    Science.gov (United States)

    Gasparini, Patrizia; Di Cosmo, Lucio; Cenni, Enrico; Pompei, Enrico; Ferretti, Marco

    2013-07-01

    In the frame of a process aiming at harmonizing National Forest Inventory (NFI) and ICP Forests Level I Forest Condition Monitoring (FCM) in Italy, we investigated (a) the long-term consistency between FCM sample points (a subsample of the first NFI, 1985, NFI_1) and recent forest area estimates (after the second NFI, 2005, NFI_2) and (b) the effect of tree selection method (tree-based or plot-based) on sample composition and defoliation statistics. The two investigations were carried out on 261 and 252 FCM sites, respectively. Results show that some individual forest categories (larch and stone pine, Norway spruce, other coniferous, beech, temperate oaks and cork oak forests) are over-represented and others (hornbeam and hophornbeam, other deciduous broadleaved and holm oak forests) are under-represented in the FCM sample. This is probably due to a change in forest cover, which has increased by 1,559,200 ha from 1985 to 2005. In case of shift from a tree-based to a plot-based selection method, 3,130 (46.7%) of the original 6,703 sample trees will be abandoned, and 1,473 new trees will be selected. The balance between exclusion of former sample trees and inclusion of new ones will be particularly unfavourable for conifers (with only 16.4% of excluded trees replaced by new ones) and less for deciduous broadleaves (with 63.5% of excluded trees replaced). The total number of tree species surveyed will not be impacted, while the number of trees per species will, and the resulting (plot-based) sample composition will have a much larger frequency of deciduous broadleaved trees. The newly selected trees have-in general-smaller diameter at breast height (DBH) and defoliation scores. Given the larger rate of turnover, the deciduous broadleaved part of the sample will be more impacted. Our results suggest that both a revision of FCM network to account for forest area change and a plot-based approach to permit statistical inference and avoid bias in the tree sample

  14. Tree-string duality

    International Nuclear Information System (INIS)

    After the termination of perturbative QCD tree evolution, colourless clusters are formed. Similarly, after the first generation cuts in the (classical) Artru-Mennessier string model, disconnected lengths of string result. The mass spectra of clusters and first generation strings are similar, and the similarity extends to the rapidity distributions as a function of mass. (author)

  15. Christmas Tree Category Manual.

    Science.gov (United States)

    Bowman, James S.; Turmel, Jon P.

    This manual provides information needed to meet the standards for pesticide applicator certification. Pests and diseases of christmas tree plantations are identified and discussed. Section one deals with weeds and woody plants and the application, formulation and effects of herbicides in controlling them. Section two discusses specific diseases…

  16. A Universal Phylogenetic Tree.

    Science.gov (United States)

    Offner, Susan

    2001-01-01

    Presents a universal phylogenetic tree suitable for use in high school and college-level biology classrooms. Illustrates the antiquity of life and that all life is related, even if it dates back 3.5 billion years. Reflects important evolutionary relationships and provides an exciting way to learn about the history of life. (SAH)

  17. The Sacred Tree.

    Science.gov (United States)

    Lethbridge Univ. (Alberta).

    Designed as a text for high school students and adults, this illustrated book presents ethical concepts and teachings of Native societies throughout North America concerning the nature and possibilities of human existence. The final component of a course in self-discovery and development, the book begins with the legend of the "Sacred Tree"…

  18. Multiscale singularity trees

    DEFF Research Database (Denmark)

    Somchaipeng, Kerawit; Sporring, Jon; Johansen, Peter;

    2007-01-01

    We propose MultiScale Singularity Trees (MSSTs) as a structure to represent images, and we propose an algorithm for image comparison based on comparing MSSTs. The algorithm is tested on 3 public image databases and compared to 2 state-of-theart methods. We conclude that the computational complexi...

  19. A Suffix Tree Or Not a Suffix Tree?

    DEFF Research Database (Denmark)

    Starikovskaya, Tatiana; Vildhøj, Hjalte Wedel

    2015-01-01

    , in particular we do not require that S ends with a unique symbol. This corresponds to considering the more general definition of implicit or extended suffix trees. Such general suffix trees have many applications and are for example needed to allow efficient updates when suffix trees are built online. We prove...

  20. The effect of felled tree stems as bio-engineering type rockfall protection

    Science.gov (United States)

    Bigot, Christophe; Bourrier, Franck; Berger, Frederic; Dorren, Luuk; Astrade, Laurent

    2010-05-01

    In mountainous regions forested slopes play an important protective role against rockfall. Up to now, most of the researches on rockfall protection forest have been and are focused on the dissipative effect of standing and living trees. There are hardly any studies on the protective capacity of tree stumps and lying stems against snow avalanches and rockfalls. Although, these techniques are more and more used throughout the Alps. In Austria, the felling technique Alpi has been developed, which allows a specialised lumberjack to create small rockfall barriers using one or two tree stems anchored on high tree stumps. Lying tree stems can be then used to increase efficiently the roughness of the soil and so to limit or avoid triggering and propagation falling rocks. But, due to the wood decay, the efficiency of such bio-engineering type protective works is decreasing with time. One of the questions that the forest and natural hazard managers have to answer is: what is the lifetime of such protective structures? In order to answer to this question we have developed a specific research on this thematic. The main objectives of this research program are to quantify the efficacy of these bio-engineering type rockfall fences depending on their characteristics (stump and stems density, position on the slope, tree species, etc.), and to evaluate their resistance over time. To achieve these objectives we have developed two types of experiments. The first one, performed during the summer 2009 on our experimental site test of Vaujany (France), are full scale rockfall experiments on four felled trees, which have been anchored on their stumps and are lying in an oblique direction to the slope. In total, fifty rocks (from 522 at 2242 kg) have been released one by one. For each rock, the trajectory has been filmed with high speed digital cameras. The second type of experiment is the uprooting of tree stumps (spruce, fir and beech) of different ages and diameter. To uproot the stumps

  1. Roost selection by barbastelle bats (Barbastella barbastellus, Chiroptera: Vespertilionidae in beech woodlands of central Italy

    Directory of Open Access Journals (Sweden)

    Danilo Russo

    2003-10-01

    Full Text Available The barbastelle bat, Barbastella barbastellus (Schreber, 1774 is a medium-sized, tree-dwelling vespertilionid classified as ?Endangered? in Italy; in western Europe it may be one of the rarest bat species. B. barbastellus shows roosting preferences that should be regarded as a key point in conservation protocols. We examined roost selection in a breeding population of B. barbastellus from the Abruzzo Lazio and Molise National Park (central Italy at three levels: woodland structure and management type; tree characteristics; and cavity characteristics. In 2001-2002, we fitted 31 adult B. barbastellus (29 lactating females, one pregnant female and one male with 0.48g radio-tags and tracked them to their roost-trees. The bats were tracked for 4.5 ± 3.7 days (range: 0-12 days. We located 33 roosts used by 25 subjects (1.8±1.2 roosts/bat, range 1-5. The bats switched roosts frequently: 13 bats used more than one tree over the study period. A chi-square analysis showed that the roosts were not distributed at random across woodland categories: unmanaged woodland was positively selected, whereas shelterwood-harvested woodland was used in proportion to its availability, and ?pastures+scattered trees? was avoided. Twenty out of 33 roost trees were dead Fagus sylvatica trees; conversely, living F. sylvatica dominated in a tree sample obtained at random; dead trees were used more than expected (Χ² test, P <0.001. Overall, roost trees were significantly taller and had a larger diameter at breast?s height and more cavities than random trees; they also had a lower percent canopy closure than random trees. To highlight which variables were actually associated with selection, we devised a logistic regression model. The full model was significant (P <0.001; removal of tree type and tree height affected the model significantly, but the other variables did not produce detectable effects. The

  2. Tree Formation Using Coordinate Method

    Directory of Open Access Journals (Sweden)

    Monika Choudhary

    2015-06-01

    Full Text Available In this paper we are introducing a new method of tree formation, we propose a coordinate based method by which we can store and access tree structures. As we know in NLP, parsing is the most important module. The output of this module is generally parsed trees. Currently, TAG (Tree Adjoining Grammar is widely used grammar due to its linguistic and formal nature. It is simply tree generating system. The unit structure used in TAG is structured trees. So we used our new method to store trees where we worked on English to Hindi language. We worked on different sentences from English to Hindi, our method is the easiest way to manipulate tree. We have implemented within small corpus and for finite number of structures and further can be extended in future.

  3. Tree Transduction Tools for Cdec

    Directory of Open Access Journals (Sweden)

    Austin Matthews

    2014-09-01

    Full Text Available We describe a collection of open source tools for learning tree-to-string and tree-to-tree transducers and the extensions to the cdec decoder that enable translation with these. Our modular, easy-to-extend tools extract rules from trees or forests aligned to strings and trees subject to different structural constraints. A fast, multithreaded implementation of the Cohn and Blunsom (2009 model for extracting compact tree-to-string rules is also included. The implementation of the tree composition algorithm used by cdec is described, and translation quality and decoding time results are presented. Our experimental results add to the body of evidence suggesting that tree transducers are a compelling option for translation, particularly when decoding speed and translation model size are important.

  4. Visual perception of tree forms

    Energy Technology Data Exchange (ETDEWEB)

    Muederrisoglu, Haldun; Eroglu, Engin; OEzkan, Suekran; Ak, Kivanc [Department of Landscape Architecture, Faculty of Forestry, Abant Izzet Baysal University, 81000, Duzce (Turkey)

    2006-06-15

    This study, made in the cities of Adapazari, Duzce, and Bolu, has three fundamental goals. The first one is the evaluation of visual quality and strength of each tree form, second is the determination of visual quality and strength of different tree forms next to each other, and the third goal of this study is determining the effects of personal characteristics to the perception of tree forms. To reach these three goals the semantic differential method was used to evaluate graphical visions of tree forms. According to the findings, trees with pyramid forms have the most effective visual quality and strength. Pyramid-formed tree combinations have higher visual quality and strength than mixed combinations do. At the same time personal characteristics are effective on the visual perception of tree forms. A strong relationship between the amount of area per person in the cities the participants live in and their visual perception of tree forms has been found. (author)

  5. Recent Trends of Tree Growth in Relation to Climate Change in Hungary

    Directory of Open Access Journals (Sweden)

    SOMOGYI, Zoltán

    2008-01-01

    Full Text Available The paper addresses two related issues. One is whether, and how, growth patterns of standmean height have changed in Hungary in the last few decades, and the other is whether recentlyobserved increases in mean annual temperature might have caused changes in growth trends. Changesin tree growth were investigated for beech (Fagus sylvatica, sessile oak (Quercus petraea andTurkey oak (Quercus cerris by comparing stand mean heights over age using data from the forestinventories of 1981 and 2001, and for sessile oak using stand mean height data from permanentsample plots since 1961. Tree growth was found to have accelerated for each species mentioned, withTurkey oak showing the largest acceleration. To study the second issue, stand mean height was relatedto elevation, wich in turn was related to mean annual temperature and precipitation. For theseanalyses, too, data of many thousands of stands in the forest inventory was used. Stand mean heightwas found to increase with decreasing elevation, i.e. with increasing mean annual temperature, foreach of the three species. As the annual precipitation and air humidity decreases with decreasingelevation, it was concluded that increases of mean annual temperature could positively have affectedtree growth in the last few decades. However, this effect is expected to be soon limited by wateravailability.

  6. Learning Stochastic Tree Edit Distance

    OpenAIRE

    Bernard, Marc; Habrard, Amaury; Sebban, Marc

    2006-01-01

    Trees provide a suited structural representation to deal with complex tasks such as web information extraction, RNA secondary structure prediction, or conversion of tree structured documents. In this context, many applications require the calculation of similarities between tree pairs. The most studied distance is likely the tree edit distance for which improvements in terms of complexity have been achieved during the last decade. However, this classic edit distance usually uses a priori fixe...

  7. Connected searching of weighted trees

    CERN Document Server

    Dereniowski, Dariusz

    2010-01-01

    In this paper we consider the problem of connected edge searching of weighted trees. It is shown that there exists a polynomial-time algorithm for finding optimal connected search strategy for bounded degree trees with arbitrary weights on the edges and vertices of the tree. The problem is NP-complete for general node-weighted trees (the weight of each edge is 1).

  8. Adjustable Chain Trees for Proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Fonseca, Rasmus

    2012-01-01

    A chain tree is a data structure for changing protein conformations. It enables very fast detection of clashes and free energy potential calculations. A modified version of chain trees that adjust themselves to the changing conformations of folding proteins is introduced. This results in much...... tighter bounding volume hierarchies and therefore fewer intersection checks. Computational results indicate that the efficiency of the adjustable chain trees is significantly improved compared to the traditional chain trees....

  9. A Class of Graceful Trees

    Institute of Scientific and Technical Information of China (English)

    孟凡洪; 苏耕; 杨继

    2000-01-01

    The present paper shows the coordinates of a tree and its vertices, defines a kind of Trees with Odd-Number Radiant Type (TONRT), deals with the gracefulness of TONRT by using the edge-moving theorem, and uses graceful TONRT to construct another class of graceful trees.

  10. The Hopi Fruit Tree Book.

    Science.gov (United States)

    Nyhuis, Jane

    Referring as often as possible to traditional Hopi practices and to materials readily available on the reservation, the illustrated booklet provides information on the care and maintenance of young fruit trees. An introduction to fruit trees explains the special characteristics of new trees, e.g., grafting, planting pits, and watering. The…

  11. PoInTree: A Polar and Interactive Phylogenetic Tree

    Institute of Scientific and Technical Information of China (English)

    Carreras Marco; Gianti Eleonora; Sartori Luca; Plyte Simon Edward; Isacchi Antonella; Bosotti Roberta

    2005-01-01

    PoInTree (Polar and Innteractive Tree) is an application that allows to build, visualize, and customize phylogenetic trees in a polar, interactive, and highly flexible view. It takes as input a FASTA file or multiple alignment formats. Phylogenetic tree calculation is based on a sequence distance method and utilizes the Neighbor Joining (NJ) algorithm. It also allows displaying precalculated trees of the major protein families based on Pfam classification. In PoInTree, nodes can be dynamically opened and closed and distances between genes are graphically represented.Tree root can be centered on a selected leaf. Text search mechanism, color-coding and labeling display are integrated. The visualizer can be connected to an Oracle database containing information on sequences and other biological data, helping to guide their interpretation within a given protein family across multiple species.The application is written in Borland Delphi and based on VCL Teechart Pro 6 graphical component (Steema software).

  12. Direct contribution of nitrogen deposition to nitrous oxide emissions in a temperate beech and spruce forest – a 15N tracer study

    Directory of Open Access Journals (Sweden)

    E. Veldkamp

    2011-03-01

    Full Text Available The impact of atmospheric nitrogen (N deposition on nitrous oxide (N2O emissions in forest ecosystems is still unclear. Our study assessed the direct contribution of N deposition to N2O emissions in temperate forests exposed to chronic high N depositions using a 15N labelling technique. In a Norway spruce stand (Picea abies and in a beech stand (Fagus sylvatica at the Solling, Germany, we used a low concentrated 15N-labelled ammonium-nitrate solution to simulate N deposition. Nitrous oxide fluxes and 15N isotope abundances in N2O were measured using the closed chamber method combined with 15N isotope analyses. Emissions of N2O were higher in the beech stand (2.6 ± 0.6 kg N ha−1 yr−1 than in the spruce stand (0.3 ± 0.1 kg N ha−1 yr−1. We observed a direct effect of N input on 15N-N2O emissions, which lasted for less than three weeks and was mainly caused by denitrification. No further increase in 15N enrichment of N2O occurred during a one-year experiment, which was probably due to immobilisation of deposited N. The annual emission factor for N2O from deposited N was 0.1% for the spruce stand and 0.6% for the beech stand. Standard methods used in the literature applied to the same stands grossly overestimated emission factors with values of up to 25%. Only 6–13% of the total N2O emissions were derived from direct N depositions. Whether the remaining emissions resulted from accumulated anthropogenic N depositions or native soil N, could not be distinguished with the applied methods. The 15N tracer technique is a useful tool, which may improve estimates of the current contribution of N deposition to N2O emissions.

  13. Fringe trees, Crump-Mode-Jagers branching processes and $m$-ary search trees

    OpenAIRE

    Holmgren, Cecilia; Janson, Svante

    2016-01-01

    This survey studies asymptotics of random fringe trees and extended fringe trees in random trees that can be constructed as family trees of a Crump-Mode-Jagers branching process, stopped at a suitable time. This includes random recursive trees, preferential attachment trees, fragmentation trees, binary search trees and (more generally) $m$-ary search trees, as well as some other classes of random trees. We begin with general results, mainly due to Aldous (1991) and Jagers and Nerman (1984). T...

  14. Estimation of canopy attributes in beech forests using true colour digital images from a small fixed-wing UAV

    Science.gov (United States)

    Chianucci, Francesco; Disperati, Leonardo; Guzzi, Donatella; Bianchini, Daniele; Nardino, Vanni; Lastri, Cinzia; Rindinella, Andrea; Corona, Piermaria

    2016-05-01

    Accurate estimates of forest canopy are essential for the characterization of forest ecosystems. Remotely-sensed techniques provide a unique way to obtain estimates over spatially extensive areas, but their application is limited by the spectral and temporal resolution available from these systems, which is often not suited to meet regional or local objectives. The use of unmanned aerial vehicles (UAV) as remote sensing platforms has recently gained increasing attention, but their applications in forestry are still at an experimental stage. In this study we described a methodology to obtain rapid and reliable estimates of forest canopy from a small UAV equipped with a commercial RGB camera. The red, green and blue digital numbers were converted to the green leaf algorithm (GLA) and to the CIE L*a*b* colour space to obtain estimates of canopy cover, foliage clumping and leaf area index (L) from aerial images. Canopy attributes were compared with in situ estimates obtained from two digital canopy photographic techniques (cover and fisheye photography). The method was tested in beech forests. UAV images accurately quantified canopy cover even in very dense stand conditions, despite a tendency to not detecting small within-crown gaps in aerial images, leading to a measurement of a quantity much closer to crown cover estimated from in situ cover photography. Estimates of L from UAV images significantly agreed with that obtained from fisheye images, but the accuracy of UAV estimates is influenced by the appropriate assumption of leaf angle distribution. We concluded that true colour UAV images can be effectively used to obtain rapid, cheap and meaningful estimates of forest canopy attributes at medium-large scales. UAV can combine the advantage of high resolution imagery with quick turnaround series, being therefore suitable for routine forest stand monitoring and real-time applications.

  15. Heterogeneous genetic structure in a Fagus crenata population in an old-growth beech forest revealed by microsatellite markers.

    Science.gov (United States)

    Asuka, Y; Tomaru, N; Nisimura, N; Tsumura, Y; Yamamoto, S

    2004-05-01

    The within-population genetic structure of Fagus crenata in a 4-ha plot (200 x 200 m) of an old-growth beech forest was analysed using microsatellite markers. To assess the genetic structure, Moran's I spatial autocorrelation coefficient was calculated. Correlograms of Moran's I showed significant positive values less than 0.100 for short-distance classes, indicating weak genetic structure. The genetic structure within the population is created by limited seed dispersal, and is probably weakened by overlapping seed shadow, secondary seed dispersal, extensive pollen flow and the thinning process. Genetic structure was detected in a western subplot of 50 x 200 m with immature soils and almost no dwarf bamboos (Sasa spp.), where small and intermediate-sized individuals were distributed in aggregations with high density because of successful regeneration. By contrast, genetic structure was not found in an eastern subplot of the same size with mature soils and Sasa cover, where successful regeneration was prevented, and the density of the small and intermediate-sized individuals was low. Moreover, genetic structure of individuals in a small-size class (diameter at breast height large-size class (diameter at breast height >/= 12 cm). The apparent genetic structure detected in the 4-ha plot was therefore probably the result of the structure in the western portion of the plot and in small and intermediate-sized individuals that successfully regenerated under the favourable environment. The heterogeneity in genetic structure presumably reflects variation in the density that should be affected by differences in regeneration dynamics associated with heterogeneity in environmental conditions.

  16. Doubly robust survival trees.

    Science.gov (United States)

    Steingrimsson, Jon Arni; Diao, Liqun; Molinaro, Annette M; Strawderman, Robert L

    2016-09-10

    Estimating a patient's mortality risk is important in making treatment decisions. Survival trees are a useful tool and employ recursive partitioning to separate patients into different risk groups. Existing 'loss based' recursive partitioning procedures that would be used in the absence of censoring have previously been extended to the setting of right censored outcomes using inverse probability censoring weighted estimators of loss functions. In this paper, we propose new 'doubly robust' extensions of these loss estimators motivated by semiparametric efficiency theory for missing data that better utilize available data. Simulations and a data analysis demonstrate strong performance of the doubly robust survival trees compared with previously used methods. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27037609

  17. Tree farming. Traedjordbruk

    Energy Technology Data Exchange (ETDEWEB)

    Falk, B. (Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Environmental Research)

    1992-07-01

    Fallowed land can initially provide very favourable conditions for tree farming, thus enabling rapid canopy closure and a short rotation period. There may be justification for fertilization, particularly close to the time of canopy closure. Heavy clay soils should be avoided on account of poor tree growth. Crosses of balsam poplar are easy to regenerate through cuttings. The plantation should either be done with small plants protected against damage by game, or with planting stems branched at the bottoms in spacing patterns that are not too dense (3.5x3.5 - 5x5m). Branches at the bottom help to avoid rubbing by deer. Drainage systems are clogged by tree roots and fields drained by subsurface drainage systems should be avoided. Open ditches are sufficient for the requirements of the trees. Selected clones of balsam poplar crosses may have great resistance against disease. However, they do not have a growth rhythm that is ideally suited to Swedish conditions. Further breeding is probably necessary. The main use for balsam poplar is expected to be in the manufacture of pulp, mechanical or chemical. Other uses are veneer, building, glulam and fuel. Under good conditions, height and diameter development suggests a very high production. In plantations with suitable spacing patterns, the economically optimum rotation time is 15-20 year and the plantation appears to withstand high demands for return on investments and price competition. Future activities should foremost be concentrated on development of additional clone material, investigations of wood quality and the establishment and following up of further production experiments. (48 refs., 6 figs., 7 tabs.).

  18. Tree farming; Traedjordbruk

    Energy Technology Data Exchange (ETDEWEB)

    Falk, B. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Environmental Research

    1992-07-01

    Fallowed land can initially provide very favourable conditions for tree farming, thus enabling rapid canopy closure and a short rotation period. There may be justification for fertilization, particularly close to the time of canopy closure. Heavy clay soils should be avoided on account of poor tree growth. Crosses of balsam poplar are easy to regenerate through cuttings. The plantation should either be done with small plants protected against damage by game, or with planting stems branched at the bottoms in spacing patterns that are not too dense (3.5x3.5 - 5x5m). Branches at the bottom help to avoid rubbing by deer. Drainage systems are clogged by tree roots and fields drained by subsurface drainage systems should be avoided. Open ditches are sufficient for the requirements of the trees. Selected clones of balsam poplar crosses may have great resistance against disease. However, they do not have a growth rhythm that is ideally suited to Swedish conditions. Further breeding is probably necessary. The main use for balsam poplar is expected to be in the manufacture of pulp, mechanical or chemical. Other uses are veneer, building, glulam and fuel. Under good conditions, height and diameter development suggests a very high production. In plantations with suitable spacing patterns, the economically optimum rotation time is 15-20 year and the plantation appears to withstand high demands for return on investments and price competition. Future activities should foremost be concentrated on development of additional clone material, investigations of wood quality and the establishment and following up of further production experiments. (48 refs., 6 figs., 7 tabs.).

  19. Wood for the trees

    Directory of Open Access Journals (Sweden)

    Rob Garbutt

    2013-10-01

    Full Text Available Our paper focuses on the materiality, cultural history and cultural relations of selected artworks in the exhibition Wood for the trees (Lismore Regional Gallery, New South Wales, Australia, 10 June – 17 July 2011. The title of the exhibition, intentionally misreading the aphorism “Can’t see the wood for the trees”, by reading the wood for the resource rather than the collective wood[s], implies conservation, preservation, and the need for sustaining the originating resource. These ideas have particular resonance on the NSW far north coast, a region once rich in rainforest. While the Indigenous population had sustainable practices of forest and land management, the colonists deployed felling and harvesting in order to convert the value of the local, abundant rainforest trees into high-value timber. By the late twentieth century, however, a new wave of settlers launched a protest movements against the proposed logging of remnant rainforest at Terania Creek and elsewhere in the region. Wood for the trees, curated by Gallery Director Brett Adlington, plays on this dynamic relationship between wood, trees and people. We discuss the way selected artworks give expression to the themes or concepts of productive labour, nature and culture, conservation and sustainability, and memory. The artworks include Watjinbuy Marrawilil’s (1980 Carved ancestral figure ceremonial pole, Elizabeth Stops’ (2009/10 Explorations into colonisation, Hossein Valamanesh’s (2008 Memory stick, and AñA Wojak’s (2008 Unread book (in a forgotten language. Our art writing on the works, a practice informed by Bal (2002, Muecke (2008 and Papastergiadis (2004, becomes a conversation between the works and the themes or concepts. As a form of material excess of the most productive kind (Grosz, 2008, p. 7, art seeds a response to that which is in the air waiting to be said of the past, present and future.

  20. Tree Interpolation in Vampire

    OpenAIRE

    McMillan, Ken; Middeldorp, Aart; Voronkov, Andrei; Blanc, Régis; Gupta, Ashutosh; Kovács, Laura; Kragl, Bernhard

    2013-01-01

    We describe new extensions of the Vampire theorem prover for computing tree interpolants. These extensions generalize Craig interpolation in Vampire, and can also be used to derive sequence interpolants. We evaluated our implementation on a large number of examples over the theory of linear integer arithmetic and integer-indexed arrays, with and without quantifiers. When compared to other methods, our experiments show that some examples could only be solved by our implementation.

  1. Effect on a long-term afforestation of pine in a beech domain in NE-Spain as reflected in soil C and N isotopic signature

    Science.gov (United States)

    Girona García, Antonio; Badía-Villas, David; González-Pérez, José Antonio; Tomás Jiménez-Morillo, Nicasio; Martí-Dalmau, Clara

    2015-04-01

    The replacement of native beech forests (Fagus sylvatica) by Scots pine (Pinus sylvestris) afforestation may exert changes in soil properties, particularly in soil organic matter (SOM) (Carceller and Vallejo, 1996). Stable isotopic signatures of light elements (d13C, d15N) in soils and plants are valuable proxies for the identification of biogeochemical processes and their rates in the pedosphere (Andreeva et al., 2013 and refs therein). In this work the C and N stable isotopic analysis is used as a proxy to detect changes in SOM surrogated to the effect of centennial replacement of beech by the Scots pinewood. Two acid soil profiles, developed on quartzites under a humid climate at an altitude of 1400-1500 masl, have been sampled in Moncayo (Iberian range, NE-Spain). For each soil profile three O-layers (litter: OL, fragmented litter OF and humified litter OH) and mineral soil horizons (Ah, E, Bhs and C) were sampled. Content and bulk isotopic signature of light elements (C and N) were analysed in a Flash 2000 elemental micro-analyser coupled via a ConFlo IV interface to a Delta V Advantage isotope ratio mass spectrometer (IRMS) (Thermo Scientific, Bremen, Germany). Isotopic ratios are reported as parts per thousand deviations from appropriate standards. The standard deviations of d13C and d15N were typically less than ± 0.05 per thousand, ± 0.2 per thousand, respectively. After 100 years since the pine afforestation, no differences on C content were observed in the O-layers, ranging from 30-47% in pine soils and 37-47 % in beech soils. Similarly, no differences on N content were observed in the O-layers, ranging from 1.24-1.86 % in pine soils and 1.70-1.71 % in beech soils. C and N contents decrease progressively in depth with the exception of E-horizons where the lowest C and N content values were found. C/N ratio is higher in pine soil (20.7-38.1) than in beech O soil horizons (21.8-27.5), showing similar behavior with soil depth. Pine biomass was slightly

  2. Direct contribution of nitrogen deposition to nitrous oxide emissions in a temperate beech and spruce forest – a 15N tracer study

    OpenAIRE

    Eickenscheidt, N.; R. Brumme; Veldkamp, E.

    2011-01-01

    The impact of atmospheric nitrogen (N) deposition on nitrous oxide (N2O) emissions in forest ecosystems is still unclear. Our study assessed the direct contribution of N deposition to N2O emissions in temperate forests exposed to chronic high N depositions using a 15N labelling technique. In a Norway spruce stand (Picea abies) and in a beech stand (Fagus sylvatica) at the Solling, Germany, we used a low concentrated 15N-labelled ammonium-nitrate solution to simulate N deposi...

  3. Transformation of even-aged European beech (Fagus sylvatica L.) to uneven-aged management under changing growth conditions caused by climate change

    DEFF Research Database (Denmark)

    Schou, Erik; Meilby, Henrik

    2013-01-01

    Transformation from even-aged to uneven-aged forest management is currently taking place throughout Europe. Climate change is, however, expected to change growth conditions—possibly quite radically. Using a deterministic approach, it was the objective of this study to investigate the influence...... of such changes on optimal transformation strategies for an even-aged stand of European Beech in Denmark. For a range of growth change scenarios, represented by changes in site index, optimal harvest policies were determined using a matrix modelling approach and a differential evolution algorithm. Transition...

  4. Tree-Ring Chronology of Pedunculate Oak (Quercus robur and its Potential for Development of Dendrochronological Research in Croatia

    Directory of Open Access Journals (Sweden)

    Katarina Čufar

    2014-06-01

    Full Text Available We present the local tree-ring chronology of pedunculate oak (Qercus robur from Kobiljak near Zagreb, Croatia (16º09’ E, 45º49’ N, 140 m a.s.l.. The chronology is based on 17 trees and is 127 years long and covers the period of 1883-2009. The well replicated part of the residual version of the ARSTAN chronology with SSS>0.80 (interval of 88 years, period 1922-2009 was used for dendroclimatological analysis, which showed that June precipitation has positive and temperature has negative effect on tree-ring variation. Comparison with 40 available oak chronologies from the surrounding countries confi rmed its good teleconnection with 2 local oak chronologies from Austria, 2 from Hungary, and 3 from Slovenia. It also exhibits good heteroconnection, i.e. similarity with chronologies of beech (Fagus sylvatica, from various sites in Slovenia. The similarities can be ascribed to response to common climatic factors. The results indicate that the chronology could be a good reference point for constructing a longer regional chronology in Croatia and surrounding countries, which could be used for different purposes including dating of objects of cultural heritage.

  5. Warm & wet or warm & dry? - A tree-ring based drought reconstruction from the European lowlands with emphasis on the medieval climate anomaly

    Science.gov (United States)

    Scharnweber, Tobias; Heinrich, Ingo; van der Maaten, Ernst; Heußner, Karl-Uwe; Wilmking, Martin

    2016-04-01

    Recent advances in reconstructing natural drought variability in Europe, such as the 'Old world drought atlas' (Cook et al., 2015), have sharpened our picture of historical hydroclimatic variability. However, our knowledge lacks high spatial resolution, especially for the northern non-arid regions. For example, it is still under debate if the so called medieval climate anomaly (MCA; ~950-1300 AD), a period of warm temperatures comparable to the contemporary warm phase, was likewise accompanied by increased drought occurrence, or, on the contrary, was rather wet (e.g. Kress et al., 2014). Here, we present a new millennial long drought reconstruction based on a unique dataset of tree rings from historical and modern beech wood from the northeastern European lowlands. Beech has a stable and strong regional summer drought signal over the calibration period of instrumental data (r>0.7 with drought index PDSI over 1900-2010) which, in contrast to other species such as oak, is consistent irrespective of the site/soil conditions the trees grew in. It can be assumed that during medieval times beech wood was available locally and not traded long distances. This strongly reduces the possibility that the new reconstruction mixes different signals of the possibly high spatial variability of precipitation. The extremely high replication of our chronology for the period 1000-1300 AD (peak in town foundations in NE-Germany) with more than 600 series enables a direct comparison with the well replicated recent period 1800-2010. In contrast to the results of Kress et al. (2014) for the Swiss Alps, but in accordance with the 'Old world drought atlas', our first results point at a rather dry and warm MCA in NE-Germany. In addition they support the observation that the hydroclimate of the twentieth century was highly variable compared with the last millennium. References Cook ER, Seager R, Kushnir Y, et al. (2015) Old World megadroughts and pluvials during the Common Era. Science

  6. Influence of windthrows and tree species on forest soil plant biomass and carbon stocks

    Science.gov (United States)

    Veselinovic, B.; Hager, H.

    2012-04-01

    The role of forests has generally been recognized in climate change mitigation and adaptation strategies and policies (e.g. Kyoto Protocol within articles 3.3 and 3.4, RES-E Directive of EU, Country Biomass Action Plans etc.). Application of mitigation actions, to decrease of CO2-emissions and, as the increase of carbon(C)-stocks and appropriate GHG-accounting has been hampered due to a lack of reliable data and good statistical models for the factors influencing C-sequestration in and its release from these systems (e.g. natural and human induced disturbances). Highest uncertainties are still present for estimation of soil C-stocks, which is at the same time the second biggest C-reservoir on earth. Spruce monocultures have been a widely used management practice in central Europe during the past century. Such stands are in lower altitudes (e.g. submontane to lower montane elevation zone) and on heavy soils unstable and prone to disturbances, especially on blowdown. As the windthrow-areas act as CO2-source, we hypothesize that conversion to natural beech and oak forests will provide sustainable wood supply and higher stability of stands against blowdown, which simultaneously provides the long-term belowground C-sequestration. This work focuses on influence of Norway spruce, Common beech and Oak stands on belowground C-dynamics (mineral soil, humus and belowground biomass) taking into consideration the increased impact of windthrows on spruce monocultures as a result of climate change. For this purpose the 300-700m altitude and pseudogley (planosols/temporally logged) soils were chosen in order to evaluate long-term impacts of the observed tree species on belowground C-dynamics and human induced disturbances on secondary spruce stands. Using the false chronosequence approach, the C-pools have been estimated for different compartments and age classes. The sampling of forest floor and surface vegetation was done using 30x30 (homogenous plots) and 50x50cm (inhomogeneous

  7. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree transduc

  8. Gene tree correction for reconciliation and species tree inference

    Directory of Open Access Journals (Sweden)

    Swenson Krister M

    2012-11-01

    Full Text Available Abstract Background Reconciliation is the commonly used method for inferring the evolutionary scenario for a gene family. It consists in “embedding” inferred gene trees into a known species tree, revealing the evolution of the gene family by duplications and losses. When a species tree is not known, a natural algorithmic problem is to infer a species tree from a set of gene trees, such that the corresponding reconciliation minimizes the number of duplications and/or losses. The main drawback of reconciliation is that the inferred evolutionary scenario is strongly dependent on the considered gene trees, as few misplaced leaves may lead to a completely different history, with significantly more duplications and losses. Results In this paper, we take advantage of certain gene trees’ properties in order to preprocess them for reconciliation or species tree inference. We flag certain duplication vertices of a gene tree, the “non-apparent duplication” (NAD vertices, as resulting from the misplacement of leaves. In the case of species tree inference, we develop a polynomial-time heuristic for removing the minimum number of species leading to a set of gene trees that exhibit no NAD vertices with respect to at least one species tree. In the case of reconciliation, we consider the optimization problem of removing the minimum number of leaves or species leading to a tree without any NAD vertex. We develop a polynomial-time algorithm that is exact for two special classes of gene trees, and show a good performance on simulated data sets in the general case.

  9. Rate of tree carbon accumulation increases continuously with tree size

    Science.gov (United States)

    Stephenson, N.L.; Das, A.J.; Condit, R.; Russo, S.E.; Baker, P.J.; Beckman, N.G.; Coomes, D.A.; Lines, E.R.; Morris, W.K.; Rüger, N.; Álvarez, E.; Blundo, C.; Bunyavejchewin, S.; Chuyong, G.; Davies, S.J.; Duque, Á.; Ewango, C.N.; Flores, O.; Franklin, J.F.; Grau, H.R.; Hao, Z.; Harmon, M.E.; Hubbell, S.P.; Kenfack, D.; Lin, Y.; Makana, J.-R.; Malizia, A.; Malizia, L.R.; Pabst, R.J.; Pongpattananurak, N.; Su, S.-H.; Sun, I-F.; Tan, S.; Thomas, D.; van Mantgem, P.J.; Wang, X.; Wiser, S.K.; Zavala, M.A.

    2014-01-01

    Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle—particularly net primary productivity and carbon storage—increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree’s total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to understand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.

  10. Save a Tree

    Science.gov (United States)

    Williams, Kathryn R.

    1999-10-01

    Starting in September 1925, JCE reproduced pictures of famous chemists or chemistry-related works of art as frontispieces. Often, the Journal included a biography or other article about the picture. The August 1945 frontispiece featured the largest cork oak in the United States. An accompanying article described the goals of the Cork Project to plant cork trees in suitable locations in the U.S., to compensate for uncertain European and African sources during World War II. The final frontispiece appeared in December 1956. To view supplementary material, please refer to JCE Online's supplementary links.

  11. The fault-tree compiler

    Science.gov (United States)

    Martensen, Anna L.; Butler, Ricky W.

    1987-01-01

    The Fault Tree Compiler Program is a new reliability tool used to predict the top event probability for a fault tree. Five different gate types are allowed in the fault tree: AND, OR, EXCLUSIVE OR, INVERT, and M OF N gates. The high level input language is easy to understand and use when describing the system tree. In addition, the use of the hierarchical fault tree capability can simplify the tree description and decrease program execution time. The current solution technique provides an answer precise (within the limits of double precision floating point arithmetic) to the five digits in the answer. The user may vary one failure rate or failure probability over a range of values and plot the results for sensitivity analyses. The solution technique is implemented in FORTRAN; the remaining program code is implemented in Pascal. The program is written to run on a Digital Corporation VAX with the VMS operation system.

  12. Influence of litter chemistry and stoichiometry on glucan depolymerization during decomposition of beech (Fagus sylvatica L.) litter.

    Science.gov (United States)

    Leitner, Sonja; Wanek, Wolfgang; Wild, Birgit; Haemmerle, Ieda; Kohl, Lukas; Keiblinger, Katharina M; Zechmeister-Boltenstern, Sophie; Richter, Andreas

    2012-07-01

    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 using beech (Fagus sylvatica, L.) litter from four different locations in Austria, differing in composition (concentration of starch, cellulose and acid unhydrolyzable residue or AUR fraction) and elemental stoichiometry (C:N:P ratio). Leaf litter was incubated in mesocosms for six months in the laboratory under controlled conditions. To investigate the process of glucan decomposition and its controls, we developed an isotope pool dilution (IPD) assay using (13)C-glucose to label the pool of free glucose in the litter, and subsequently measured the dilution of label over time. This enabled us to calculate gross rates of glucose production through glucan depolymerization, and glucose consumption by the microbial community. In addition, potential activities of extracellular cellulases and ligninases (peroxidases and phenoloxidases) were measured to identify effects of resource chemistry and stoichiometry on microbial enzyme production. Gross rates of glucan depolymerization and glucose consumption were highly correlated, indicating that both processes are co-regulated and intrinsically linked by the microbial demand for C and energy and thereby to resource allocation to enzymes that depolymerize glucans. At early stages of decomposition, glucan depolymerization rates were correlated with starch content, indicating that starch was the primary source for glucose. With progressing litter decomposition, the correlation with starch diminished and glucan depolymerization rates were

  13. Limit theorems for sequences of random trees

    OpenAIRE

    Balding, David; Ferrari, Pablo A.; Fraiman, Ricardo; Sued, Mariela

    2004-01-01

    We consider a random tree and introduce a metric in the space of trees to define the ``mean tree'' as the tree minimizing the average distance to the random tree. When the resulting metric space is compact we have laws of large numbers and central limit theorems for sequence of independent identically distributed random trees. As application we propose tests to check if two samples of random trees have the same law.

  14. Effects of tree and herb biodiversity on Diptera, a hyperdiverse insect order.

    Science.gov (United States)

    Scherber, Christoph; Vockenhuber, Elke A; Stark, Andreas; Meyer, Hans; Tscharntke, Teja

    2014-04-01

    Biodiversity experiments have shown that plant diversity has largely positive effects on insect diversity and abundance. However, such relationships have rarely been studied in undisturbed and more complex ecosystems such as forests. Flies (Diptera) are among the most dominant taxa in temperate ecosystems, influencing many ecosystem processes. As it is unknown how Diptera respond to changes in forest biodiversity, we examined how community characteristics of Diptera respond to varying levels of tree and herb diversity and vegetation structure. The study was conducted in the Hainich National Park (Central Germany) on 84 plots along a gradient of tree (from two to nine species) and herb (from two to 28 species) diversity. We found that herb and canopy cover as well as spatial effects were the best predictors of Diptera community composition, consisting of 62 families, including 99 Empidoidea and 78 Phoridae species. Abundance of Empidoidea was positively influenced by herb diversity, indicating bottom-up control. A complex causal pathway influenced Dipteran species richness: species-rich forest stands, with low beech cover, had lower canopy cover, resulting in higher Dipteran species richness. In addition, Diptera benefited from a more dense and diverse herb community. Individual species responded differentially to herb layer diversity, indicating that effects of plant diversity on higher trophic levels depend on species identity. We conclude that tree and herb canopy cover as well as herb diversity predominately shape Dipteran communities in temperate deciduous forests, which is in contrast to expectations from grassland studies exhibiting much closer relationships between plant and insect diversity. PMID:24394862

  15. The Steiner tree problem

    CERN Document Server

    Hwang, FK; Winter, P

    1992-01-01

    The Steiner problem asks for a shortest network which spans a given set of points. Minimum spanning networks have been well-studied when all connections are required to be between the given points. The novelty of the Steiner tree problem is that new auxiliary points can be introduced between the original points so that a spanning network of all the points will be shorter than otherwise possible. These new points are called Steiner points - locating them has proved problematic and research has diverged along many different avenues. This volume is devoted to the assimilation of the rich field of intriguing analyses and the consolidation of the fragments. A section has been given to each of the three major areas of interest which have emerged. The first concerns the Euclidean Steiner Problem, historically the original Steiner tree problem proposed by Jarník and Kössler in 1934. The second deals with the Steiner Problem in Networks, which was propounded independently by Hakimi and Levin and has enjoyed the most...

  16. Distributed Merge Trees

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, Dmitriy; Weber, Gunther

    2013-01-08

    Improved simulations and sensors are producing datasets whose increasing complexity exhausts our ability to visualize and comprehend them directly. To cope with this problem, we can detect and extract significant features in the data and use them as the basis for subsequent analysis. Topological methods are valuable in this context because they provide robust and general feature definitions. As the growth of serial computational power has stalled, data analysis is becoming increasingly dependent on massively parallel machines. To satisfy the computational demand created by complex datasets, algorithms need to effectively utilize these computer architectures. The main strength of topological methods, their emphasis on global information, turns into an obstacle during parallelization. We present two approaches to alleviate this problem. We develop a distributed representation of the merge tree that avoids computing the global tree on a single processor and lets us parallelize subsequent queries. To account for the increasing number of cores per processor, we develop a new data structure that lets us take advantage of multiple shared-memory cores to parallelize the work on a single node. Finally, we present experiments that illustrate the strengths of our approach as well as help identify future challenges.

  17. The Hill and the Trees

    Institute of Scientific and Technical Information of China (English)

    王燕文

    2007-01-01

    Once there was a well-known hill here. There were many lush trees, beautiful flowers and green grasses on it. One day, the hill said to the trees proudly, “Look, how beautiful I am! But you look so ugly on my back. It must be better if I could drive you away.” One of the trees said, “You won't have beautiful and green clothing without us trees? If you leave us, you will die away.” The hill laughed and said again,”I feel very ashamed for I am staying with you together. Sooner or later I will drive you all...

  18. Human decision error (HUMDEE) trees

    Energy Technology Data Exchange (ETDEWEB)

    Ostrom, L.T.

    1993-08-01

    Graphical presentations of human actions in incident and accident sequences have been used for many years. However, for the most part, human decision making has been underrepresented in these trees. This paper presents a method of incorporating the human decision process into graphical presentations of incident/accident sequences. This presentation is in the form of logic trees. These trees are called Human Decision Error Trees or HUMDEE for short. The primary benefit of HUMDEE trees is that they graphically illustrate what else the individuals involved in the event could have done to prevent either the initiation or continuation of the event. HUMDEE trees also present the alternate paths available at the operator decision points in the incident/accident sequence. This is different from the Technique for Human Error Rate Prediction (THERP) event trees. There are many uses of these trees. They can be used for incident/accident investigations to show what other courses of actions were available and for training operators. The trees also have a consequence component so that not only the decision can be explored, also the consequence of that decision.

  19. Tree felling: a necessary evil

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    CERN started a campaign of tree felling in 2010 for safety reasons, and it will continue this year in various parts of the Meyrin site. As in previous years, the trees cut down in 2013 will be recycled and some will be replaced.   Diseased tree that had to be cut down on the Meyrin site. In association with the Geneva nature and countryside directorate (Direction générale de la nature et du paysage, DGNP), CERN commissioned the Geneva school of landscaping, engineering and architecture (Haute école du paysage, d’ingénierie et d’architecture, HEPIA) to compile an inventory of the trees on the Meyrin site. In total, 1285 trees (excluding poplars) were recorded. 75.5% of these trees were declared to be in a good state of health (i.e. 971 trees), 21.5% in a moderate state of health (276 trees) and 3% in a poor state of health (38 trees). As for the poplars, the 236 specimens recorded on the Meyrin site were judged to be too old, to...

  20. A Catskill Flora and Economic Botany, III: Apetalae. Including the Poplars, Willows, Hickories, Birches, Beeches, Oaks, Elms, Nettles, Sorrels, Docks, and Smartweeds. Bulletin No. 443, New York State Museum.

    Science.gov (United States)

    Brooks, Karl L.

    This compendium deals with the ecology and economic importance of the poplars, willows, hickories, birches, beeches, oaks, elms, nettles, sorrels, docks, and smartweeds growing in New York's Catskills. Provided are keys for identifying each plant to species by flowers, foliage, or winter buds. A line drawing accompanies a summary of basic data…

  1. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  2. Sussing Merger Trees: A proposed Merger Tree data format

    CERN Document Server

    Thomas, Peter A; Tweed, Dylan; Benson, Andrew J; Croton, Darren; Elahi, Pascal; Henriques, Bruno; Iliev, Ilian T; Knebe, Alexander; Lux, Hanni; Mao, Yao-Yuan; Neyrinck, Mark; Pearce, Frazer R; Rodriguez-Gomez, Vicente; Schneider, Aurel; Srisawat, Chaichalit

    2015-01-01

    We propose a common terminology for use in describing both temporal merger trees and spatial structure trees for dark-matter halos. We specify a unified data format in HDF5 and provide example I/O routines in C, FORTRAN and PYTHON.

  3. Tree Decomposition based Steiner Tree Computation over Large Graphs

    OpenAIRE

    Wei-Kleiner, Fang

    2013-01-01

    In this paper, we present an exact algorithm for the Steiner tree problem. The algorithm is based on certain pre-computed index structures. Our algorithm offers a practical solution for the Steiner tree problems on graphs of large size and bounded number of terminals.

  4. The impact of winter and spring temperatures on temperate tree budburst dates: results from an experimental climate manipulation.

    Directory of Open Access Journals (Sweden)

    Yongshuo H Fu

    Full Text Available Budburst phenology is a key driver of ecosystem structure and functioning, and it is sensitive to global change. Both cold winter temperatures (chilling and spring warming (forcing are important for budburst. Future climate warming is expected to have a contrasting effect on chilling and forcing, and subsequently to have a non-linear effect on budburst timing. To clarify the different effects of warming during chilling and forcing phases of budburst phenology in deciduous trees, (i we conducted a temperature manipulation experiment, with separate winter and spring warming treatments on well irrigated and fertilized saplings of beech, birch and oak, and (ii we analyzed the observations with five temperature-based budburst models (Thermal Time model, Parallel model, Sequential model, Alternating model, and Unified model. The results show that both winter warming and spring warming significantly advanced budburst date, with the combination of winter plus spring warming accelerating budburst most. As expected, all three species were more sensitive to spring warming than to winter warming. Although the different chilling requirement, the warming sensitivity was not significantly different among the studied species. Model evaluation showed that both one- and two- phase models (without and with chilling, respectively are able to accurately predict budburst. For beech, the Sequential model reproduced budburst dates best. For oak and birch, both Sequential model and the Thermal Time model yielded good fit with the data but the latter was slightly better in case of high parameter uncertainty. However, for late-flushing species, the Sequential model is likely be the most appropriate to predict budburst data in a future warmer climate.

  5. Carbon and Nitrogen dynamics in forest soils depending on light conditions and tree species

    Science.gov (United States)

    Veselinovic, Bojana; Hager, Herbert

    2013-04-01

    Climate change mitigation actions under the Kyoto Protocol apply among other decreases of CO2-emissions and/or increases of carbon (C) stocks. As soils represent the second biggest C-reservoir on Earth, an exact estimation of the stocks and reliable knowledge on C-dynamics in forest soils is of high importance. Anyhow, here, the accurate GHG-accounting, emission reductions and increase in C stocks is hampered due to lack of reliable data and solid statistical methods for the factors which influence C-sequestration in and its release from these systems. In spite of good progress in the scientific research, these factors are numerous and diverse in their interactions. This work focuses on influence of the economically relevant tree species - Picea abies, Fagus sylvatica and Quercus spp. - and light conditions on forest floor and mineral soil C and N dynamics in forest soils. Spruce monocultures have been widely used management practices in central European forests during the past century. Such stands are in lower altitudes and on heavy and water logged soils unstable and prone to disturbances, especially to windthrows. We hypothesize that windthrow areas loose C & N and that the establishment of the previous nutrient stocks is, if at all, only possible to be reached over the longer periods of time. We research also how the increased OM depletion affects the change of C & N stocks in forest floor vs. mineral soil. Conversion of such secondary spruce monocultures to site adequate beech and oak forests may enable higher stocks allocated predominantly as stable organic carbon and as plant available nitrogen. For this purpose sites at 300-700 m altitude with planosols were chosen in the region of the Northern Alpine Foothills. A false chronosequence approach was used in order to evaluate the impacts of the tree species and change in light conditions on dynamic of C & N in the forest floor and mineral soil, over the period 0-100 (for oak 120 y.) years. The C- and N

  6. On aligning trees

    CERN Document Server

    Calder, J

    1997-01-01

    The increasing availability of corpora annotated for linguistic structure prompts the question: if we have the same texts, annotated for phrase structure under two different schemes, to what extent do the annotations agree on structuring within the text? We suggest the term tree alignment to indicate the situation where two markup schemes choose to bracket off the same text elements. We propose a general method for determining agreement between two analyses. We then describe an efficient implementation, which is also modular in that the core of the implementation can be reused regardless of the format of markup used in the corpora. The output of the implementation on the Susanne and Penn treebank corpora is discussed.

  7. Tree Quantum Field Theory

    CERN Document Server

    Gurau, R; Rivasseau, V

    2008-01-01

    We propose a new formalism for quantum field theory which is neither based on functional integrals, nor on Feynman graphs, but on marked trees. This formalism is constructive, i.e. it computes correlation functions through convergent rather than divergent expansions. It applies both to Fermionic and Bosonic theories. It is compatible with the renormalization group, and it allows to define non-perturbatively {\\it differential} renormalization group equations. It accommodates any general stable polynomial Lagrangian. It can equally well treat noncommutative models or matrix models such as the Grosse-Wulkenhaar model. Perhaps most importantly it removes the space-time background from its central place in QFT, paving the way for a nonperturbative definition of field theory in noninteger dimension.

  8. Fires on trees

    CERN Document Server

    Bertoin, Jean

    2010-01-01

    We consider random dynamics on the edges of a uniform Cayley tree with $n$ vertices, in which edges are either inflammable, fireproof, or burt. Every inflammable edge is replaced by a fireproof edge at unit rate, while fires start at smaller rate $n^{-\\alpha}$ on each inflammable edge, then propagate through the neighboring inflammable edges and are only stopped at fireproof edges. A vertex is called fireproof when all its adjacent edges are fireproof. We show that as $n\\to \\infty$, the density of fireproof vertices converges to 1 when $\\alpha>1/2$, to 0 when $\\alpha<1/2$, and to some non-degenerate random variable when $\\alpha=1/2$. We further study the connectivity of the fireproof forest, in particular the existence of a giant component.

  9. Random Projection Trees Revisited

    CERN Document Server

    Dhesi, Aman

    2010-01-01

    The Random Projection Tree structures proposed in [Freund-Dasgupta STOC08] are space partitioning data structures that automatically adapt to various notions of intrinsic dimensionality of data. We prove new results for both the RPTreeMax and the RPTreeMean data structures. Our result for RPTreeMax gives a near-optimal bound on the number of levels required by this data structure to reduce the size of its cells by a factor $s \\geq 2$. We also prove a packing lemma for this data structure. Our final result shows that low-dimensional manifolds have bounded Local Covariance Dimension. As a consequence we show that RPTreeMean adapts to manifold dimension as well.

  10. TREE DECOMPOSITIONS OF MULTIGRAPHS

    Institute of Scientific and Technical Information of China (English)

    SHI Minyong

    1999-01-01

    For a graph G, ifE(G) can be partitioned into several pairwise disjointsets as { E1, E2,……,El} such thatthe subgraph induced by Ei is a tree of orderki, (i=1,2, ……, l), then G is said to have a {k1,k2,……, kl}-tree-decomposition, denoted by {k1,k2,……, kl}∈G.For k≥1 and l≥0, a collection(G)(k,l) is the setof multigraphs such that G∈(G)(k,l) if and only if ε(G) = k(|G|-1)-l and ε(H)≤max{(k-1)(|H|-1), k(|H|-1)-l} for any subgraph H of G.We prove that (1) If k≥2, 0≤l≤3 and G∈(G)(k,l) of order n≥l+1, then {n,n,……, n-l}∈ G. (2) If k≥2 and G∈(G)(k,2) oforder n≥3, then {n,n,……, n,n-2}∈G and {n,n,……, n,n-1,n-1}∈G. (3) If k3 and G∈(G)(k,3) oforder n≥4, then {n,n,……, n,n-3}∈G ,{ n,n,……, n,n-1,n-2}∈ G and {n,n, ……, n,n-1,n-1,n-1}∈G.

  11. Misunderstanding sap ascent in trees

    OpenAIRE

    Cochard, Hervé; Delzon, Sylvain

    2013-01-01

    Trees transport water from their roots to their leaves thanks to an efficient but vulnerable vascular system. Assessing the vulnerability to drought of the xylem and its ability to recover from failure are not an easy task but recent findings demonstrate that, contrary to what is commonly believed, hydraulic failure and embolism repair are not routine in trees.

  12. Tree Hydraulics: How Sap Rises

    Science.gov (United States)

    Denny, Mark

    2012-01-01

    Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

  13. Some Hopf algebras of trees

    NARCIS (Netherlands)

    Laan, P. van der

    2001-01-01

    In the literature several Hopf algebras that can be described in terms of trees have been studied. This paper tries to answer the question whether one can understand some of these Hopf algebras in terms of a single mathematical construction. The starting point is the Hopf algebra of rooted trees as

  14. Community tree nursery, Meru, Kenya.

    OpenAIRE

    2006-01-01

    This is a photograph of a community tree nursery, Meru, Kenya. In this nursery a community group has started a nursery to provide seedlings for their own forest reforestation projects as well as for sale. This shows that use of common pool resources and shows community forestry activities that also do private tree planting on homesteads.

  15. Modelling tree biomasses in Finland

    Energy Technology Data Exchange (ETDEWEB)

    Repola, J.

    2013-06-01

    Biomass equations for above- and below-ground tree components of Scots pine (Pinus sylvestris L), Norway spruce (Picea abies [L.] Karst) and birch (Betula pendula Roth and Betula pubescens Ehrh.) were compiled using empirical material from a total of 102 stands. These stands (44 Scots pine, 34 Norway spruce and 24 birch stands) were located mainly on mineral soil sites representing a large part of Finland. The biomass models were based on data measured from 1648 sample trees, comprising 908 pine, 613 spruce and 127 birch trees. Biomass equations were derived for the total above-ground biomass and for the individual tree components: stem wood, stem bark, living and dead branches, needles, stump, and roots, as dependent variables. Three multivariate models with different numbers of independent variables for above-ground biomass and one for below-ground biomass were constructed. Variables that are normally measured in forest inventories were used as independent variables. The simplest model formulations, multivariate models (1) were mainly based on tree diameter and height as independent variables. In more elaborated multivariate models, (2) and (3), additional commonly measured tree variables such as age, crown length, bark thickness and radial growth rate were added. Tree biomass modelling includes consecutive phases, which cause unreliability in the prediction of biomass. First, biomasses of sample trees should be determined reliably to decrease the statistical errors caused by sub-sampling. In this study, methods to improve the accuracy of stem biomass estimates of the sample trees were developed. In addition, the reliability of the method applied to estimate sample-tree crown biomass was tested, and no systematic error was detected. Second, the whole information content of data should be utilized in order to achieve reliable parameter estimates and applicable and flexible model structure. In the modelling approach, the basic assumption was that the biomasses of

  16. Ozone exposure, defoliation of beech (Fagus sylvatica L.) and visible foliar symptoms on native plants in selected plots of South-Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, Marco [Dipartimento di Biologia Vegetale, Universita di Firenze, Piazzale Cascine 28, I-50144 Florence (Italy)]. E-mail: m.ferretti@linnaea.it; Calderisi, Marco [Dipartimento di Biologia Vegetale, Universita di Firenze, Piazzale Cascine 28, I-50144 Florence (Italy)]. E-mail: calderisi@chemiometria.it; Bussotti, Filippo [Dipartimento di Biologia Vegetale, Universita di Firenze, Piazzale Cascine 28, I-50144 Florence (Italy)]. E-mail: filippo.bussotti@unifi.it

    2007-02-15

    The relationships between crown defoliation of beech, visible foliar symptoms on native vegetation and ozone exposure were investigated on permanent monitoring sites in South-Western Europe in the years 2000-2002. Relationships between defoliation of beech and O{sub 3} (seasonal mean, 2-week maximum, AOT40) were investigated by means of multiple regression models (11 plots, 1-3 years of data each) and a model based on temporal autocorrelation of defoliation data (14 plots, 1-3 years of data each). Different multiple regression techniques were used. The four models generated (R {sup 2} = 0.71-0.85, explained variance in cross-validation 61-78%) identified several significant predictors of defoliation, with AOT40 (p = 0.008) and foliar content of phosphorous (p = 0.0002-0.0004) being common to all models. The autocorrelation model (R {sup 2} = 0.55; p < 0.0001) was used to calculate expected defoliation on the basis of the previous year's defoliation, and model predictions were used as an estimate of expected defoliation under constant site and environmental condition. Residuals (predicted-measured) plotted against current AOT40 shows that a possible effect of ozone occurs only at very high AOT40 (>35,000 ppbh). O{sub 3}-like visible foliar symptoms were recorded on 65 species at 47% of the common monitoring sites in 2001 and 38% in 2002. No relationship was found between O{sub 3} exposure, frequency of symptomatic sites and frequency of species with symptoms (R {sup 2} = 0.11; p > 0.05). A number of questions related to the ecological and methodological basis of the survey were identified. Inherent sampling and non-sampling errors and multicollinearity of the data suggest great caution when examining results obtained from mensurational, correlative studies. - Ozone AOT40 was identified as a significant predictor of defoliation of beech, but a limited relationship was found between ozone exposure and visible symptoms on native vegetation.

  17. Spanning Trees in Random Satisfiability Problems

    OpenAIRE

    Ramezanpour, A.; Moghimi-Araghi, S.

    2005-01-01

    Working with tree graphs is always easier than with loopy ones and spanning trees are the closest tree-like structures to a given graph. We find a correspondence between the solutions of random K-satisfiability problem and those of spanning trees in the associated factor graph. We introduce a modified survey propagation algorithm which returns null edges of the factor graph and helps us to find satisfiable spanning trees. This allows us to study organization of satisfiable spanning trees in t...

  18. Ectomycorrhizal identification in environmental samples of tree roots by Fourier-transform infrared (FTIR spectroscopy

    Directory of Open Access Journals (Sweden)

    Rodica ePena

    2014-05-01

    Full Text Available Roots of forest trees are associated with various ectomycorrhizal (ECM fungal species that are involved in nutrient exchange between host plant and the soil compartment. The identification of ECM fungi in small environmental samples is difficult. The present study tested the feasibility of attenuated total reflection Fourier-transform infrared (ATR-FTIR spectroscopy followed by hierarchical cluster analysis (HCA to discriminate in situ collected ECM fungal species. Root tips colonized by distinct ECM fungal species, i.e., Amanita rubescens, Cenococcum geophilum, Lactarius subdulcis, Russula ochroleuca, and Xerocomus pruinatus were collected in mono-specific beech (Fagus sylvatica and mixed deciduous forests in different geographic areas to investigate the environmental variability of the ECM FTIR signatures.A clear HCA discrimination was obtained for ECM fungal species independent of individual provenance. Environmental variability neither limited the discrimination between fungal species nor provided sufficient resolution to discern species sub-clusters for different sites. However, the de-convoluted FTIR spectra contained site-related spectral information for fungi with wide nutrient ranges, but not for Lactarius subdulcis, a fungus residing only in the litter layer. Specific markers for distinct ECM were identified in spectral regions associated with carbohydrates (i.e. mannans, lipids, and secondary protein structures. The present results support that FTIR spectroscopy coupled with multivariate analysis is a reliable and fast method to identify ECM fungal species in minute environmental samples. Moreover, our data suggest that the FTIR spectral signatures contain information on physiological and functional traits of ECM fungi.

  19. Assessment of a relaxed eddy accumulation for measurements of fluxes of biogenic volatile organic compounds: Study over arable crops and a mature beech forest

    DEFF Research Database (Denmark)

    Gallagher, M.W.; Clayborough, R.; Beswick, K.M.;

    2000-01-01

    (Fagus Sylvatica) during the FOREXNOX program. Measurements from a site where winter wheat and barley (Hordeum Vulgare ann Triticum Aestivum) were being harvested are also presented. The system was inter-compared with two different eddy correlation systems for measuring CO2 fluxes. Good results were...... obtained with correlation coefficients for the REA system ranging from 0.71 to 0.82, lending further confidence in the use of this technique, Daily averaged biogenic emissions from the wheat and barley canopies were significantly larger than expected, likely a result of harvesting. Fluxes measured over...... the beech canopy were also larger than might be expected from northern latitude deciduous forests. (C) 2000 Elsevier Science Ltd. All rights reserved....

  20. Are There Infinite Irrigation Trees?

    Science.gov (United States)

    Bernot, M.; Caselles, V.; Morel, J. M.

    2006-08-01

    In many natural or artificial flow systems, a fluid flow network succeeds in irrigating every point of a volume from a source. Examples are the blood vessels, the bronchial tree and many irrigation and draining systems. Such systems have raised recently a lot of interest and some attempts have been made to formalize their description, as a finite tree of tubes, and their scaling laws [25], [26]. In contrast, several mathematical models [5], [22], [10], propose an idealization of these irrigation trees, where a countable set of tubes irrigates any point of a volume with positive Lebesgue measure. There is no geometric obstruction to this infinitesimal model and general existence and structure theorems have been proved. As we show, there may instead be an energetic obstruction. Under Poiseuille law R(s) = s -2 for the resistance of tubes with section s, the dissipated power of a volume irrigating tree cannot be finite. In other terms, infinite irrigation trees seem to be impossible from the fluid mechanics viewpoint. This also implies that the usual principle analysis performed for the biological models needs not to impose a minimal size for the tubes of an irrigating tree; the existence of the minimal size can be proven from the only two obvious conditions for such irrigation trees, namely the Kirchhoff and Poiseuille laws.

  1. A multi-layer, closed-loop system for continuous measurement of soil CO2 concentrations and its isotopic signature applied in a beech and a pine forest

    Science.gov (United States)

    Jochheim, Hubert; Wirth, Stephan

    2016-04-01

    We present a setup of measurement devices that allows the application of the soil CO2 gradient approach for CO2 efflux calculation in combination with the analysis of isotopic signature (δ13C). Vertical profiles of CO2 concentrations in air-filled pores of soil were measured using miniature NDIR sensors within a 16-channel closed-loop system where equilibrium with soil air can be achieved using hydrophobic, gas-permeable porous polypropylene tubes circulating gas using peristaltic pumps. A 16-position multiplexer allows the connection to an isotopic CO2 analyser. This setup was applied at two ICP Forest intensive monitoring sites, a beech and a pine forest on sandy soils located in Brandenburg, Germany. CO2 concentrations in air-filled pores of soils were measured on top of soil surface, below the humus layer, and in 10cm, 20cm, 30cm and 100 cm depths every 30 min. At both sites, soil moisture and temperature were measured continuously in the respective soil depths in identical time intervals. Isotopic signatures of soil CO2 was detected by measurement campaigns. After three years of measurements, our results provided evidence for distinct seasonal dynamics and vertical gradients of soil CO2 concentration and δ13C values. Varying impacts of soil temperature and moisture on CO2 concentration were revealed, highlighting its impact on soil physical and soil biological controls. Higher levels of CO2 concentration and a more distinct seasonal dynamics were detected at the beech site compared to the pine site. The collected data provide a suitable database for calculation of CO2 efflux and modelling of soil respiration.

  2. What Good Is a Tree?

    Institute of Scientific and Technical Information of China (English)

    Lowell; Ponte; 史书碧

    1998-01-01

    文章开头说:Trees are so common and quiet that we pay them little mind. 其实,初见此标题——What Good Is a Tree?笔者也pay this essay little mind。这个题目还能够讲出多少新意来呢?不料,细读之后,竟不忍释手! Trees sustain our lives and our planet in a thousand practical ways. Trees do more than make life pleasant;they make life possible. 这是文章的两句主题句。读罢全文,认真一想,便觉这决非耸人听闻之言:无言的树,“挪死”的树,支撑着我们这个星球,庇护着天下的生灵!诸如: …they draw carbon dioxide from the air…and oxygen iS released. Without tree our entire world would be a much drier place. For centuries,the Chinese have derived medicines form the ginkgo tree. 让读者双眼一亮的是,文章提供了许多你我都不曾想到的有关树的信息: a.树木能彼此互通信息: …trees send unseen signals to each other.When willows are attacked bywebworms and tent caterpillars,they give off a chemical that alerts nearby trees.Theneighboring trees respond by pumping more tannin into their leaves,making them moredifficult for the insects tO digest。 更让人?

  3. Răspunsul comparativ al fagului şi stejarului la secetă în Rezervaţia Naturală Codrii (R. Moldova [Comparative response of beech and oak to drought in Codrii Natural Reserve (R. Moldova

    Directory of Open Access Journals (Sweden)

    Popa Ionel

    2015-08-01

    Full Text Available Drought is main climatic risk factor in Republic of Moldova with major effects on economic and ecologic level. Regional climatic models indicate for Moldova an increase of temperature and decrease of precipitation during the summer in the future decades. We evaluated the response of beech and oak to cumulative water deficit using SPEI index at different time scales. Results of climate-growth correlations indicate a higher sensitivity of beech to drought comparing with oak. Maximum correlation for beech is observed at 18-20 month SPEI scale (0.60 and for oak at time scale of 12-18 month, but lower (0.45. Earlywood growth index of oak are low correlated with SPEI. Oak, a more tolerant drought species, is more adapted compared with beech under the forescasted climatic changes in this region.

  4. Tree for all reasons

    Energy Technology Data Exchange (ETDEWEB)

    Sang, T.

    1980-04-01

    For centuries Chinese peasants have planted paulownia trees, not only for their beauty but also for their fast-growing characteristics - an amazing average of 0.37 cubic meters of timber per year. The leaves, flowers, fruits and bark can be used as medicines and, because of their high nitrogen content the leaves are used as fodder. But above all, paulownias are increasingly being used by Chinese peasants to boost grain output. In Lanka county, Henan province, for example, grain output has increased to an average of 5.25 tons per hectare from less than 0.75 tons in 1963 when paulownia interplanting as a system was introduced. They help crops to withstand sandstorms, droughts and frosts, they increase air humidity and reduce evaporation of moisture in the fields. They do not compete with crops for fertilizer and water since about 80% of their absorbing roots reach a depth of 40-100 cm, while most cereals roots are less than 40 cm.

  5. Counting spanning trees in graphs

    OpenAIRE

    Azarija, Jernej

    2012-01-01

    The history of counting the number of spanning trees dates back into the year 1842 in which the German mathematician Gustav Kirchhoff derived a relation between the number of spanning trees of a graph G (τ(G)) and the determinant of a specific submatrix associated with G. After this result many other related results followed. For example in 1889 the British mathematician A. Cayley showed that the complete graph on n nodes has nn−2 spanning trees.The function τ can nowadays be found in the fi...

  6. Trees Are Useful to Man

    Institute of Scientific and Technical Information of China (English)

    赵明

    2005-01-01

    Trees are useful to man in three impor-tant ways. They provide him with wood and other products;they give him shade;they help prevent drought(干旱)and floods. Unfortunately,in many parts of the world, man has not realized that the third one is the most important. Two thousand years ago a rich and pow-erful country cut down its trees to build war-ships, with which to gain itself an empire. It gained the empire,however,without its trees, its soil became hard and poor. When the em-pire fell to pieces, the home c...

  7. Implementing Municipal Tree Planting: Los Angeles Million-Tree Initiative

    OpenAIRE

    Pincetl, Stephanie

    2010-01-01

    Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic—living—infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were prim...

  8. Stable Ca Isotopes in Tamarix aphylla Tree Rings, Death Valley, California

    Science.gov (United States)

    Yang, W.; Depaolo, D. J.; Ingram, B. L.; Owens, T. L.

    2008-12-01

    As a dune stabilizer and windbreak, Tamarix aphylla is an exotic perennial and evergreen tree in Death Valley. Its tap roots can reach down to 30 m depth and sub-superficial side roots may reach 50 m horizontally. The species can store large amounts of water in its roots and undergoes high evapotranspiration. Since Tamarix aphylla is a perennial tree growing in desert environments and its roots reach deep to the water table, it could be a proxy for desert ecological and hydrologic systems through time. We measured Ca isotopes in the soluble fraction of 8 tree ring samples from a 50-year-old specimen growing on an alluvial fan in Death Valley near Furnace Creek. Previous studies (Yang et al, GCA 60, 1996) indicate that this tree's rings contain high sulfur concentrations (4-6% expressed as sulfate) with chemical composition of CaSO4 (0.15-0.62 H2O). The δ34S values of soluble sulfate increase from +13.5 to +18 permil VCDT from the core to the bark, which are interpreted as reflecting deeper sulfate sources as the tree grew. The δ13C variations of the tree-ring cellulose (-27.6 to -24.0 permil VPDB) reflect changes in the local precipitation and show that Tamarix aphylla undergoes C3 photosynthesis. The δ44Ca for the soluble sulfate Ca through the tree-ring section, which covers a time period from 1945 to 1993, have an average value -2.52 permil (-3.4 permil relative to seawater). Only small variations are observed, from -2.69 to -2.28; the highest value (for 1990) occurs near the end of an extended drought. These are the first measurements of tree rings, but the low δ44Ca values are consistent with previous measurements of beech roots and stems from a temperate forest (Page et al., Biogeochem. 88, 2008). In our case, the tree has only one Ca source, which is expected to be isotopically uniform and similar to both local rainfall and limestones (δ44Ca ~ -0.6 permil), and with the minimal vegetation and extensive deep root system it is unlikely that there is a

  9. A suffix tree or not a suffix tree?

    DEFF Research Database (Denmark)

    Starikovskaya, Tatiana; Vildhøj, Hjalte Wedel

    2015-01-01

    In this paper we study the structure of suffix trees. Given an unlabeled tree τ on n nodes and suffix links of its internal nodes, we ask the question “Is τ a suffix tree?”, i.e., is there a string S whose suffix tree has the same topological structure as τ? We place no restrictions on S...... if τ is a suffix tree is not an easy task, because, with no restrictions on the final symbol, we cannot guess the length of a string that realizes τ from the number of leaves. And without an upper bound on the length of such a string, it is not even clear how to solve the problem by an exhaustive...... search. In this paper, we prove that τ is a suffix tree if and only if it is realized by a string S of length n-1, and we give a linear-time algorithm for inferring S when the first letter on each edge is known. This generalizes the work of I et al. (2014) [15]. [All rights reserved Elsevier]....

  10. Implementing Municipal Tree Planting: Los Angeles Million-Tree Initiative

    Science.gov (United States)

    Pincetl, Stephanie

    2010-02-01

    Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic—living—infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were primarily qualitative, involving interviews, attending meetings and conducting literature reviews. Results indicate that multiple nonprofit and city agency programs are involved in planting and maintaining trees and this has required coordination among groups that here-to-fore were unaccustomed to having to collaborate. The main finding that emerge from this research is that the implementation of such a program in Los Angeles is more complicated than it may seem due to several interacting factors: the need to rely on multiple public and private organizations to put trees into the ground and to maintain them; coordination of these multiple efforts must be centralized, but requires a great deal of time and effort and maybe resisted by some of the partners; funding for planting and long term maintenance must be pieced together from multiple sources; acceptance of trees by residents varies by neighborhood as does tree canopy cover; appropriate nursery supply can be limited; the location of the program within the city administration is determined by who initiates the program.

  11. Implementing municipal tree planting: Los Angeles million-tree initiative.

    Science.gov (United States)

    Pincetl, Stephanie

    2010-02-01

    Urban forests are increasingly being seen as an important infrastructure that can help cities remediate their environmental impacts. This work reports on the first steps in implementing a million tree program in Los Angeles and the ways such a biogenic-living-infrastructure has been approached. Numbers of studies have been done to quantify the benefits of urban forests, but little has been written on the process of implementing urban tree planting programs. The investigative methods were primarily qualitative, involving interviews, attending meetings and conducting literature reviews. Results indicate that multiple nonprofit and city agency programs are involved in planting and maintaining trees and this has required coordination among groups that here-to-fore were unaccustomed to having to collaborate. The main finding that emerge from this research is that the implementation of such a program in Los Angeles is more complicated than it may seem due to several interacting factors: the need to rely on multiple public and private organizations to put trees into the ground and to maintain them; coordination of these multiple efforts must be centralized, but requires a great deal of time and effort and maybe resisted by some of the partners; funding for planting and long term maintenance must be pieced together from multiple sources; acceptance of trees by residents varies by neighborhood as does tree canopy cover; appropriate nursery supply can be limited; the location of the program within the city administration is determined by who initiates the program. PMID:20016982

  12. The dependence of natural regeneration of forest trees on upper soil conditions and acidity at damaged sites in the Black Forest, Germany

    International Nuclear Information System (INIS)

    It was the goal of this study to investigate the influence of different upper soil conditions on the germination and establishment, as well as the growth, of young plants of various tree species. For this purpose, four test plots in the region of the Black Forest were laid out, in which, by various means of site preparation and fertilization, the upper soils were changed. Natural seeding of common spruce, European silver-fir, beech, sycamore maple, European mountainash, and grey alder was simulated by means of controlled sowing. For comparison, a greenhouse experiment was carried out, examining the germination and development of the same tree species in various soil substrata, using different fertilizers, and under the influence of artificial acid rain. The most important results - with a high level of variation depending on the tree species examined - can be summarized as follows: Based on the results of field and greenhouse experiments, as well as on the investigations of other authors, it can be concluded that natural regeneration of forest stands is considerably impeded under conditions of increasing soil acidity and by high acid depositions. This is seen directly as the result of unfavorable chemical conditions in the upper soil, as well as indirectly due to deteriorating competitiveness against other vegetation. Site preparation and lime or dolomite fertilization can be important measures in the practice of forestry, to encourage natural regeneration in highly acidic sites with an unfavourable humus layer and a high presence of competing vegetation. (orig./UWA). 2 figs., 85 tabs., 269 refs

  13. Trees : relief for the city

    NARCIS (Netherlands)

    Hiemstra, J.A.; Schoenmaker-van der Bijl, E.; Tonneijck, A.E.G.; Hoffman, M.H.A.

    2008-01-01

    Mogelijkheden ter bestrijding van fijnstofThis brochure describes the underlying principles that form a basis for better-informed choices with regards to the management of trees and shrubs in cities and the design of functional planting schemes.

  14. Visualizing Contour Trees within Histograms

    DEFF Research Database (Denmark)

    Kraus, Martin

    2010-01-01

    Many of the topological features of the isosurfaces of a scalar volume field can be compactly represented by its contour tree. Unfortunately, the contour trees of most real-world volume data sets are too complex to be visualized by dot-and-line diagrams. Therefore, we propose a new visualization...... that is suitable for large contour trees and efficiently conveys the topological structure of the most important isosurface components. This visualization is integrated into a histogram of the volume data; thus, it offers strictly more information than a traditional histogram. We present algorithms...... to automatically compute the graph layout and to calculate appropriate approximations of the contour tree and the surface area of the relevant isosurface components. The benefits of this new visualization are demonstrated with the help of several publicly available volume data sets....

  15. Algorithms for Decision Tree Construction

    KAUST Repository

    Chikalov, Igor

    2011-01-01

    The study of algorithms for decision tree construction was initiated in 1960s. The first algorithms are based on the separation heuristic [13, 31] that at each step tries dividing the set of objects as evenly as possible. Later Garey and Graham [28] showed that such algorithm may construct decision trees whose average depth is arbitrarily far from the minimum. Hyafil and Rivest in [35] proved NP-hardness of DT problem that is constructing a tree with the minimum average depth for a diagnostic problem over 2-valued information system and uniform probability distribution. Cox et al. in [22] showed that for a two-class problem over information system, even finding the root node attribute for an optimal tree is an NP-hard problem. © Springer-Verlag Berlin Heidelberg 2011.

  16. Spanning Tree Based Attribute Clustering

    DEFF Research Database (Denmark)

    Zeng, Yifeng; Jorge, Cordero Hernandez

    2009-01-01

    inconsistent edges from a maximum spanning tree by starting appropriate initial modes, therefore generating stable clusters. It discovers sound clusters through simple graph operations and achieves significant computational savings. We compare the Star Discovery algorithm against earlier attribute clustering...

  17. Efficient Frequent Pattern Tree Construction

    Directory of Open Access Journals (Sweden)

    D.Bujji Babu

    2014-03-01

    Full Text Available Association rule learning is a popular and well researched technique for discovering interesting relations between variables in large databases in the area of data mining. The association rules are a part of intelligent systems. Association rules are usually required to satisfy a user-specified minimum support and a user-specified minimum confidence at the same time. Apriori and FP-Growth algorithms are very familiar algorithms for association rule mining. In this paper we are more concentrated on the Construction of efficient frequent pattern trees. Here, we present the novel frequent pattern trees and the performance issues. The proposed trees are fast and efficient trees helps to extract the frequent patterns. This paper provides the major advantages in the FP-Growth algorithm for association rule mining with using the newly proposed approach.

  18. Tree and tree-like species of Mexico: gymnosperms, monocotyledons, and tree ferns

    OpenAIRE

    Martin Ricker; Hernández, Héctor M.

    2010-01-01

    Trees or tree-like plants are defined here broadly as perennial, self-supporting plants with an adult height of at least 5 m (without ascending leaves or inflorescences), and with 1 or several erect stems with a diameter of at least 10 cm. We present an updated list of all Mexican tree species under that definition in the Gymnospermae (86 species, 38% endemic to Mexico), Monocotyledonae (75 species, 55% endemic), and Pteridophyta (9 species, none endemic). The list contains a total of 170 spe...

  19. Short Tree, Long Tree, Right Tree, Wrong Tree: New Acquisition Bias Corrections for Inferring SNP Phylogenies.

    Science.gov (United States)

    Leaché, Adam D; Banbury, Barbara L; Felsenstein, Joseph; de Oca, Adrián Nieto-Montes; Stamatakis, Alexandros

    2015-11-01

    Single nucleotide polymorphisms (SNPs) are useful markers for phylogenetic studies owing in part to their ubiquity throughout the genome and ease of collection. Restriction site associated DNA sequencing (RADseq) methods are becoming increasingly popular for SNP data collection, but an assessment of the best practises for using these data in phylogenetics is lacking. We use computer simulations, and new double digest RADseq (ddRADseq) data for the lizard family Phrynosomatidae, to investigate the accuracy of RAD loci for phylogenetic inference. We compare the two primary ways RAD loci are used during phylogenetic analysis, including the analysis of full sequences (i.e., SNPs together with invariant sites), or the analysis of SNPs on their own after excluding invariant sites. We find that using full sequences rather than just SNPs is preferable from the perspectives of branch length and topological accuracy, but not of computational time. We introduce two new acquisition bias corrections for dealing with alignments composed exclusively of SNPs, a conditional likelihood method and a reconstituted DNA approach. The conditional likelihood method conditions on the presence of variable characters only (the number of invariant sites that are unsampled but known to exist is not considered), while the reconstituted DNA approach requires the user to specify the exact number of unsampled invariant sites prior to the analysis. Under simulation, branch length biases increase with the amount of missing data for both acquisition bias correction methods, but branch length accuracy is much improved in the reconstituted DNA approach compared to the conditional likelihood approach. Phylogenetic analyses of the empirical data using concatenation or a coalescent-based species tree approach provide strong support for many of the accepted relationships among phrynosomatid lizards, suggesting that RAD loci contain useful phylogenetic signal across a range of divergence times despite the

  20. Quantum Simulation of Phylogenetic Trees

    OpenAIRE

    Ellinas, Demosthenes; Jarvis, Peter

    2011-01-01

    Quantum simulations constructing probability tensors of biological multi-taxa in phylogenetic trees are proposed, in terms of positive trace preserving maps, describing evolving systems of quantum walks with multiple walkers. Basic phylogenetic models applying on trees of various topologies are simulated following appropriate decoherent quantum circuits. Quantum simulations of statistical inference for aligned sequences of biological characters are provided in terms of a quantum pruning map o...