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How competitive is the‘pioneer-climax’tree species Nothofagus alpina in pristine temperate forests of Chile?

Journal of Plant Ecology 2019年第1期12卷 144-156页

作者： Rebekka Bögelein Cecilia APérez Philipp Schäferand Frank M.Thomas Faculty of Regional and Environmental Sciences GeobotanyUniversity of TrierBehringstraße 2154296 TrierGermany Present address:Thünen-Institut Institut für WaldökosystemeAlfred-Möller-Straße 116225 EberswaldeGermany Departamento de Ecología de Ecosistemas Instituto de Ecología y Biodiversidad(IEB)Alameda 340SantiagoChile

Aims Nothofagus species are constitutive elements of the temperate forests along the Southern Andes mountains.The deciduous Nothofagus alpina is a fast-growing,but long-lived opportunistic pioneer spe-cies(‘pioneer-climax species’)and co-occurs with the evergreen N.dombeyi.We tested whether N.alpina is competitively superior to N.dombeyi in mature stands and whether intra-specific competition in N.alpina is stronger than inter-specific competition with N.dombeyi.methods In a pristine old-growth forest in South-Central Chile,we compared the growth of N.alpina trees in pure stands and in mixture with N.dombeyi to the growth of N.dombeyi and calculated compe-tition indices.We related growth variables to climate data and weather extremes.Important Findings In N.alpina,juvenile basal area increment was signifi-cantly higher in pure than in mixed stands.Contrary to our hypothesis,N.dombeyi exhibited larger radial stem increments than N.alpina in the most recent 40 years.In the most recent two decades,this was caused by high growth rates of large N.dombeyi trees.In both Nothofagus species,stem growth was negatively related to temperature,but N.dombeyi responded more sensitively to weather conditions than N.alpina.In N.alpina,stem increment was negatively related to the intensity of competition,but the size of the competition effects on this species was similar in pure and mixed stands.Thus,compared to N.alpina,the‘pioneer-climax species’concept is even more appropriate for N.dombeyi with its relatively high growth rates even in the early stages of its life.

关键词： competition index dendroecology growth-competition relationship pointer year productivity tree-ring analysis

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Growth of the tropical Pinus kesiya as influenced by climate and nutrient availability along an elevational gradient

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Journal of Plant Ecology 2020年第1期13卷 97-106页

作者： Le Tuan Ho Raimund schneider frank m.thomas Department of Geobotany University of TrierFaculty of Regional and Environmental SciencesBehringstraße 2154296 TrierGermany Department of Forest Resources management Faculty of ForestryNong Lam University HCMCThu Duc DistrictHo Chi Minh CityVietnam Department of Soil Science University of TrierFaculty of Regional and Environmental SciencesBehringstraße 2154296 TrierGermany

与温带地区相比,人们对在热带山脉中,尤其是热带针叶林中,沿海拔梯度的个体树种生长减少的原因知之甚少。我们的研究目的是检验气候或土壤条件是否会导致在高海拔分布的卡西亚松(Pinus kesiya,一种在南亚和东南亚广泛分布的松树)的生长... 详细信息

与温带地区相比,人们对在热带山脉中,尤其是热带针叶林中,沿海拔梯度的个体树种生长减少的原因知之甚少。我们的研究目的是检验气候或土壤条件是否会导致在高海拔分布的卡西亚松(Pinus kesiya,一种在南亚和东南亚广泛分布的松树)的生长减少。我们对越南中南部山脉中沿海拔梯度约在900~2000米之间的卡西亚松的树干直径增量和其年轮中^(13)C(△^(13)C)的同位素判别进行分析。同时确定其生长与△^(13)C、气候和土壤变量的关系。研究发现,树木的断面积生长量(BAI)与温度或降水之间没有一致的相关关系。相反,沿海拔梯度,我们发现BAI与△^(13)C以及与上层矿质土壤的C/N比和δ^(15)N特征呈显著负相关。BAI与土壤中有效磷(P_(a))和“碱性”阳离子(钙、镁、钾)的浓度呈正相关。我们的结论是,较高海拔下的较低温度会对树木生长产生间接影响,主要通过产生较高的C/N比并降低氮(N)和P矿化率而产生作用,而这些影响因其他负面反馈而进一步受到阻碍。主要包括:降水增加的淋溶作用而导致较低浓度的“碱性”阳离子以及较高海拔土壤矿化的N和P的有效性降低。本研究结果可以进一步解释卡西亚松的最高生长极限以及该物种在其他山区出现的情况。

关键词：树木生态学松树指示年土壤养分稳定同位素

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Stand structure and productivity of Populus euphratica along a gradient of groundwater distances at the tarim River(NW china)

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Journal of Plant Ecology 2017年第5期10卷 753-764页

作者： frank m.thomas michael Jeschke Ximing Zhang Petra Lang Geobotany Faculty of Regional and Environmental SciencesUniversity of TrierBehringstraße 2154296 TrierGermany Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences40 South Beijing Road830011 UrumqiChina

Aims Along central-Asian rivers in arid regions,lowering of the ground-water level constitutes a major threat to the riparian forests,whose tree layers are dominated by Euphrates poplar(Populus euphratica).Some of these fragile ecosystems are supplied with additional(‘eco-logical’)water for protection and conservation.We investigated interrelationships among groundwater distance,stand structure and above-ground wood production(at the tree and the stand level)in P.euphratica stands along a groundwater gradient(distances of 2.0-12.0 m)that also included a plot supplied with‘ecological water’.methods We measured the height,diameter at breast height and basal area of poplar trees and determined the annual above-ground wood production for the three most recent years on the basis of tree-ring analyses and allometric regressions at three sites at the upper,mid-dle and lower reaches of the tarim River,Xinjiang,NW china.Important Findingsthe distribution of age classes differed significantly among the plots:in accordance with their life histories,stands growing at a larger distance to the groundwater harboured a larger fraction of old trees(>80 years)and,in most cases,a smaller fraction of young trees(≤20 years).the annual above-ground wood production per ha was highest on a plot with a short groundwater distance(2.0 m;maxi-mum of the 3-year investigation period:3.0 t ha−1 a−1)and lowest,at a plot with a large distance to the water table(6.6 m;minimum:0.23 t ha^(−1)a^(−1)).However,the plot located close to the groundwater(and to the river)at the middle reaches exhibited a relatively large interannual variation in above-ground wood production,which can be attributed to interannual variations in the river discharge.At the middle and the lower reaches,these interannual variations on plots with the most favourable water supply were even more obvious at the tree level.For the fraction of mature trees(60-99 years old),no significant differences in above-ground wood production were found between the plots with the most and the l

关键词： allometry ground water life history tree-age distribution tugai forest

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Weather or weathering?Growth of Nothofagus dombeyi on volcanic soils differing in nitrogen and phosphorus concentrations

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Journal of Plant Ecology 2016年第5期9卷 596-607页

作者： Christoph Walter Cecilia A.Pérez frank m.thomas Faculty of Regional and Environmental Sciences GeobotanyUniversity of TrierBehringstraße 2154296 TrierGermany Departamento de Ecología de Ecosistemas Instituto de Ecología y Biodiversidad(IEB)Alameda 340SantiagoChile

Aims We tested whether—in addition to weather conditions—the concentrations of nitrogen and phosphorus in the substrate have an effect on the radial stem increment of Nothofagus dombeyi trees in old-growth forest stands on volcanic soil at the western slopes of the Andes in South-Central Chile.methods We took soil samples and tree increment cores from five proximate sites(1000-1300 m a.s.l.)that are located in the volcanic region of the Conguillío National Park and differ in the age of the substrate(miocene—3500 years B.P.)and in its concentrations of nitrogen(N)and phosphorus(P).The soil samples were also analysed on their concentrations of other plant mineral nutrients,carbon(C)and nitrogen isotope ratios(δ^(15)N).Tree-ring widths and the stem basal area increment(BAI)were related to climate parameters.In selected tree rings,the stable isotope ratios of carbon(δ^(13)C)and oxygen(δ^(18)O)were determined and related to growth and climate parameters.Important FindingsConsistent with theory,the soils on the oldest substrate showed the highest(least negative)δ^(15)N values,but mineral N was the only nutrient whose concentration exhibited a straightforward(increasing)relationship with increasing substrate age.The BAI was largest on the soil with the highest concentration of plant-available P.In contrast to BAI,tree-ring chronologies did not differ among the study sites.However,tree-ring chronologies and BAI exhibited significantly positive correlations with summer precipitation,and negative correlations,with summer(December)temperature.A negative correlation was found betweenδ^(13)C and precipitation anomalies in the growing season(November-march).We interpret the negative correlations between growth and temperature,and betweenδ^(13)C andδ^(18)O in the tree rings,as an impairment of net carbon assimilation by anomalously warm weather conditions during the growing season.We conclude that the growth of N.dombeyi is mainly affected by high temperature and low precipitation in spring and summer irrespective of the substr

关键词： Andisol annual ring dendroecology temperate broadleaf forest weather anomalies

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Clones or no clones：genetic structure of riparian Populus euphratica forests in Central Asia

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Journal of Arid Land 2018年第5期10卷 750-766页

作者： Katja KRAmP thomas schmITT Petra LANG michael JEschKE philipp schAFERI Dustin KULANEK ZHANG Ximing YU Ruide frank m.thomas Senckenberg German Entomological Institute Eberswalder StraBe 90 Muncheberg 15374 Germany Department of Zoology Faculty Natural Sciences I Institute of Biology Martin Luther University Halle-Wittenberg Halle (SaMe) 06099 Germany Faculty of Regional and Environmental Sciences University of Trier Campus II BehringstraBe 21 Trier 54296 Germany Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Sino-German Joint Research Center for the management of Ecosystems and Environmental Changes in Arid Lands (mEECAL) Urumqi 830011 China

many riparian（Tugai） forests growing along rivers in arid and hyper-arid regions of Central Asia are dominated by the Euphrates poplar（Populus euphratica）. Besides generative reproduction, which is only possible upon flooding events and at a distance to the groundwater of less than 2 m, this phreatophytic tree species also reproduces vegetatively by forming clones that can cover land surface areas of several hectares. Along a gradient of groundwater distances, we investigated whether the fraction of clones in P. euphratica stands（1） increases with increasing distance to the water table;（2） is higher if supplied with water via river cut-offs; and（3） approaches 100% at a short distance to the groundwater, but at high salt concentrations in the upper soil layers, which would prevent germination and establishment of seedlings. AFLP（Amplified Fragment Length Polymorphism） analyses were conducted on leaf samples taken from mature P. euphratica trees growing at the fringes of the Taklimakan Desert in stands with different distances（2–12 m） to the groundwater at two plots at the middle and the lower reaches of the Tarim River and in a stand close to Ebinur Lake, Xinjiang, China. Genetic diversity was large among plots, but considerably smaller within plots. We found the highest genetic diversity（caused by regeneration from seeds） at plots that have a short distance to the groundwater or are supplied with additional water. There was no significant relationship between groundwater distance and clonal fraction. All investigated trees at the saline Ebinur Lake site belonged to one single clone. Our results demonstrate that the genetic pattern of this widespread species is not easily predictable even over small distances as it is a result of a complex interplay of stand history and dispersal of propagules（pollen, seeds, and vegetative diaspores） by wind and water. In conservation and restoration schemes, P. euphratica stands with a high genetic diversity and stands that grow at short distances to the water table and are regul

关键词： clonality floodplain forest ground water phreatophyte population genetics rejuvenation salinity

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Regulation of the water status in three co-occurring phreatophytes at the southern fringe of the Taklamakan Desert

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Journal of Plant Ecology 2008年第4期1卷 227-235页

作者： frank m.thomas Andrea Foetzki Dirk Gries Helge Bruelheide Xiangyi Li Fanjiang Zeng Ximing Zhang Department of Plant Ecology Albrecht von Haller Institute for Plant SciencesGeorg-August-Universitat GottingenUntere Karspule 237073 GottingenGermany Present address:Department of Geobotany University of TrierBehringstraße 2154296 TrierGermany Eidgenossisches Institut fur Agrarokologie und Landwirtschaft Forschungsanstalt AgroscopeReckenholzstrasse 1918046 ZurichSwitzerland Institute of Geobotany and Botanical Garden Martin Luther University Halle-WittenbergAm Kirchtor 106108 Halle(Saale)Germany Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences40 South Beijing Road830011 UrumqiChina

Aims We investigated the regulation of the water status in three predominant perennial C3 phreatophytes(Alhagi sparsifolia,Populus euphratica,Tamarix ramosissima)at typical sites of their occurrence at the southern fringe of the hyperarid Taklamakan Desert(north-west China).methods In the foreland of the river oasis of Qira(Cele),we determined meteorological variables,plant biomass production,plant water potentials(WL)and the water flux through the plants.We calculated the hydraulic conductance on the flow path from the soil to the leaves(kSL)and tested the effects of kSL,WL and the leaf-to-air difference in the partial pressure of water vapour(Dw)on stomatal regulation using regression analyses.Important Findings Despite high values of plant water potential at the point of turgor loss,all plants sustained WL at levels that were high enough to maintain transpiration throughout the growing season.In A.sparsifolia,stomatal resistance(rs;related to leaf area or leaf mass)was most closely correlated with kSL;whereas in P.euphratica,~70%of the variation in rs was explained by Dw.In T.ramosissima,leaf area-related rs was significantly correlated with WL and kSL.The regulation mechanisms are in accordance with the growth patterns and the occurrence of the species in relation to their distance to the ground water.

关键词： aboveground growth extreme aridity stomatal conductance transpirational demand vapour pressure deficit

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Influence of structural depth of laser-patterned steel surfaces on the solid lubricity of carbon nanoparticle coatings

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Friction 2023年第7期11卷 1276-1291页

作者： Timothy mACLUCAS Lukas DAUT philipp GRÜTZmACHER maria Agustina GUITAR Volker PRESSER Carsten GACHOT Sebastian SUAREZ frank mÜCKLICH Chair of Functional materials Saarland UniversitySaarbrücken 66123Germany Institute for Engineering Design and Product Development TU WienWien 1060Austria INm–Leibniz Institute for New materials Saarbrücken 66123Germany Department of materials Science&Engineering Saarland UniversitySaarbrücken 66123Germany Saarene-Saarland Center for Energy materials and Sustainability Saarbrücken 66123Germany

Carbon nanoparticle coatings on laser-patterned stainless-steel surfaces present a solid lubrication system where the pattern's recessions act as lubricant-retaining reservoirs.This study investigates the influence of the structural depth of line patterns coated with multi-walled carbon nanotubes(CNTs)and carbon onions(COs)on their respective potential to reduce friction and wear.Direct laser interference patterning(DLIP)with a pulse duration of 12 ps is used to create line patterns with three different structural depths at a periodicity of 3.5μm on AISI 304 steel platelets.Subsequently,electrophoretic deposition(EPD)is applied to form homogeneous carbon nanoparticle coatings on the patterned platelets.Tribological ball-on-disc experiments are conducted on the as-described surfaces with an alumina counter body at a load of 100 mN.The results show that the shallower the coated structure,the lower its coefficient of friction(COF),regardless of the particle type.Thereby,with a minimum of just below 0.20,CNTs reach lower COF values than COs over most of the testing period.The resulting wear tracks are characterized by scanning electron microscopy,transmission electron microscopy,and energy-dispersive X-ray spectroscopy.During friction testing,the CNTs remain in contact,and the immediate proximity,whereas the CO coating is largely removed.Regardless of structural depth,no oxidation occurs on CNT-coated surfaces,whereas minor oxidation is detected on CO-coated wear tracks.

关键词： solid lubricant coatings carbon nanotubes carbon onions direct laser interference patterning(DLIP)surface structuring electrophoretic deposition(EPD)

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Changes in higher order aberrations after central corneal regularization-a comparative two-year analysis of a semiautomated topography-guided photorefractive keratectomy combined with corneal cross-linking

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Eye and Vision 2020年第1期7卷 99-108页

作者： Katja C.Iselin philipp B.Baenninger Lucas m.Bachmann frank Bochmann michael A.Thiel Claude Kaufmann Department of Ophthalmology Lucerne Cantonal HospitalLucerneSwitzerland medignition Healthcare Innovations ZurichSwitzerland

Background:The optical quality in progressive keratoconus deteriorates due to ectasia and distortion of the corneal shape and optics.While corneal cross-linking(CXL)aims at stopping disease progression,“CXL-Plus”combines CXL with excimer laser ablation to improve visual function.Central Corneal Regularization(CCR)represents a therapeutic excimer laser modality specifically designed to smoothen the ectatic corneal shape and to reduce higher order aberrations(HOA).We set out to compare CXL-Plus,consisting of CXL combined with CCR,with CXL by itself for patients with progressive keratoconus.methods:Retrospective 2-year matched group analysis of patients who either underwent CXL-Plus(n=28)or CXL as a sole procedure(n=28)for progressive keratoconus.main outcome parameters were HOA,visual function and tomographic results 12 and 24 months postoperatively.Results:After 12 months,the total HOA root mean square wavefront error was reduced from 0.79±0.30 to 0.40±0.19μm(CXL-Plus;pm 0.71±0.28 to 0.73±0.36μm(CXL;p=0.814).Uncorrected distance visual acuity improved from 0.70±0.35 to 0.36±0.29 logmAR(CXL-Plus;p=0.0002)and from 0.65±0.39 to 0.46±0.37 logmAR(CXL;p=0.067),translating to gains of three or more lines in 50%(CXL-Plus)and 36%(CXL)of patients.The steepest keratometry value(Kmax)regressed by 5.84 D(CXL-Plus;pmeters a statistically significant change could be shown between 12 and 24 months.Conclusions:CXL-Plus in the form of a CCR reduces HOA and Kmax more effectively than CXL as a sole procedure.

关键词： Keratoconus Corneal cross-linking CXL-plus Photorefractive keratectomy Central corneal regularization Higher order aberrations Coma-like aberrations

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On the calibration of rotational augmentation models for wind turbine load estimation by means of CFD simulations

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Acta mechanica Sinica 2020年第2期36卷 306-319页

作者： Belen Soledad Burgos Tafur Elia Daniele Bernhard Stoevesandt philipp thomas Fraunhofer IWES Am Seedeich 4527572 BremerhavenGermany Flensburg University of Applied Sciences Wind Energy Technology InstituteNordstraße224943 FlensburgGermany

In this work the improved version of an engineering model which accounts for rotational augmentation effects by means of computational fluid dynamics(CFD)calibration is explored and discussed.Based on an analysis of the NREL Phase VI wind turbine,the novel modeling is presented,which uses as base line the formulation proposed by Chaviaropoulos and Hansen.The model is calibrated based on CFD simulations using OpenFOAm.The corresponding correction of the two dimensional polars is straightforward implemented within moWiT,an in-house software for load calculation.The novel formulation results in improved lift and drag coefficients prediction in all considered cases,reducing the deviation with respect to the rotating CFD cases down to few percent.The optimal configuration including the correction for tip effects of Shen shows better agreements at the very tip of the blade.Furthermore the range of applicability for large wind turbine rotor blades based on a virtual 10mW rotor model is discussed.

关键词： calculation. rotational correction

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Retinal microvascular signs and recurrent vascular events in patients with TIA or minor stroke

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Stroke & Vascular Neurology 2023年第5期8卷 379-386,I0001-I0007页

作者： philipp Klyscz thomas Ihl Inga Laumeier maureen Steinicke matthias Endres Georg michelson Heinrich J Audebert Neurology Charité-Universitätsmedizin BerlinBerlinGermany Center for Stroke Research Berlin Charité-Universitätsmedizin BerlinBerlinGermany Berlin Institute of Health BerlinGermany Excellence Cluster NeuroCure Charité-Universitätsmedizin BerlinBerlinGermany German Center for Neurodegenerative Diseases partner site BerlinGermany German Center for Cardiovascular Research partner site BerlinGermany Ophthalmology Friedrich-Alexander-Universität Erlangen-Nürnberg Medizinische FakultätErlangenGermany Talkingeyes&more GmbH ErlangenGermany

Background and purpose Retinal pathologies are an independent risk factor for ischaemic stroke,but research on the predictive value of retinal abnormalities for recurrent vascular events in patients with prior stroke is inconclusive.We investigated the association of retinal pathologies with subsequent vascular events.methods In a substudy of the Intensified secondary prevention intending a reduction of recurrent events in TIA and minor stroke patients(INSPiRE-TmS)trial,we enrolled patients with recent transient ischaemic attack(TIA)or minor stroke with at least one modifiable risk factor.Primary outcome was the composite of subsequent vascular events.Retinal photographs were taken at baseline and categorised into three different fundus groups by a telemedically linked ophthalmologist.Results 722 patients participated in the current study and 109 major vascular events occurred.After multivariable adjustments,we did not find a significant association between fundus categories and risk for subsequent vascular events(HRs for moderate vascular retinopathy and vascular retinopathy with vessel rarefaction in comparison to no vascular retinopathy 1.03(95%CI 0.64 to 1.67),p=0.905 and 1.17(95%CI 0.62 to 2.20),p=0.626).In a selective post hoc analysis in patients with diabetes mellitus and hypertension,patients with vascular retinopathy with vessel rarefaction had a higher risk for recurrent stroke(HR 24.14(95%CI 2.74 to 212.50),p=0.004).Conclusions Retinal changes did not predict major subsequent vascular events in patients with recent TIA or minor stroke.Further studies are needed to examine the utility of fundus photography in assessing the risk of stroke recurrence in patients with diabetes mellitus and hypertension.

关键词： patients Retinal prevention

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