Übersicht über die Projekte
DFG-Research Unit 816: Biodiversity and Sustainable Management in a Megadiverse Mountain Ecosystem in South Ecuador
DFG-Research Unit 402: Functionality in a Tropical Mountain Rainforest
Graduate College 1086: The role of biodiversity for biogeochemical cycles and biotic interactions in temperate deciduous forests
1b-Excellenzcluster: Functional Biodiversity Research FBR
Virtual Institute for Macroecology (VIMO)
Research Unit 562: Dynamics of soil processes
Alexandra Zach, Viviana Horna, Christoph Leuschner
Duration: April 2005 - March 2007
Funded by: DFG (
Forschergruppe 402)
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Sophie Graefe, Dietrich Hertel, Christoph Leuschner
Duration: April 2005 - March 2007
Funded by: DFG (
Forschergruppe 402)
The aim of our project is to investigate lifespan and resource acquisition of fine roots in a South Ecuadorian montane rainforest at different altitudes ranging from 1,000 to 3,000 m asl. We apply methods such as 14C AMS dating, rhizoscopy, miniature sap flow measurements and 15N application. Furthermore, the influence of desiccation and fertilization on root growth will be experimentally tested. The project is part of the Research Unit 402 of the DFG “Functionality of a Tropical Rainforest: diversity, dynamic processes and utilization potentials under ecosystem perspectives”.
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Helmut Dalitz, Jürgen Homeier
Duration: April 2005 - March 2007
Funded by: DFG (
Forschergruppe 402)
The diversity of tree species and their spatial distribution are important structural parameters in tropical rainforests. They have a determining influence on biotic and abiotic factors. Previuos investigations have shown a high spatial and temporal differentiation of light, nutrient and water conditions in the closed forest, which is caused by differences in the canopy structure. Our main hypothesis is: A high number of tree species causes a spatial differentiation of abiotic parameters, which leads to a diversification of niches and therefore to the maintenance of high species numbers. The database Visual Plants (
www.visualplants.de), which is already used in the research framework will be improved, especially the determination functions. This will be realised by the implementing of expert systems and fuzzy logic. The content has to be extended and should also include images of juvenile plants.
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Gerald Moser, Dietrich Hertel, Christoph Leuschner
Duration: January 2003 - January 2005 (completed)
Funded by: DFG (
Forschergruppe 402)
Along an elevational transect from 1050 to 3100 m in the South Ecuadorian Andes, we investigate forest above-ground biomass, fine root biomass, fine root turnover, root:shoot ratio and basic microclimatological parameters. Study objective is to analyse elevational changes in biomass allocation and to relate them to changes in temperature, soil moisture and nutrient availability. We found a large increase in root:shoot ratio with elevation, which possibly is caused by a slowing down of nutrient cycling in high elevations.
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Marina Röderstein, Dietrich Hertel, Christoph Leuschner
Duration: August 2001 - August 2003 (completed)
Funded by: DFG (
Forschergruppe 402)
Elevational transects in mountains may be used to investigate the response of ecosystems to global warming. We investigated fine root biomass and fine root turnover in three stands of tropical montane rainforest in South Ecuador (Loja region) at 1890, 2450 and 3100 m elevation. Remarkably, fine root biomass and turnover increased with elevation despite a large decrease in tree height and above-ground biomass. It is hypothesized that lowered temperatures increasingly hamper nutrient turnover and thus lead to an increased root:shoot ratio of trees at high elevations.
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Jürgen Homeier, Viviana Horna, Dietrich Hertel, Christoph Leuschner
Duration: August 2007 - August 2010 (completed)
Funded by: DFG (
Research Unit 816)
Increasing fertilizer use, industrialisation and biomass burning will greatly increase atmospheric nitrogen deposition in tropical countries in the coming decades. It is not sufficiently understood how tropical forests will respond to the expected N addition. In tropical lowland forests, phosphorus is a major growth-limiting element, whereas tropical mountain forests seem to be limited primarily by N. This project combines experimental and descriptive studies along an elevational transect (1000 to 3000 m asl) of Andean mountain forests to investigate (a) the type of nutrient limitation at different elevations, (b) physiological and morphological responses of trees to N and/or P addition, (c) the relationship of tree diversity and stand productivity, respectively, to nutrient availability, and (d) the effect of elevation on the relationships in (b) and (c).
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Bärbel Wittich, Viviana Horna, Christoph Leuschner
Duration: August 2007 - August 2010 (completed)
Funded by: DFG (
Research Unit 816)
Increasing fertilizer use, industrialisation and biomass burning will greatly increase atmospheric nitrogen deposition in tropical countries in the coming decades. It is not sufficiently understood how tropical forests will respond to the expected N addition. In tropical lowland forests, phosphorus is a major growth-limiting element, whereas tropical mountain forests seem to be limited primarily by N. This project combines experimental and descriptive studies along an elevational transect (1000 to 3000 m asl) of Andean mountain forests to investigate (a) the type of nutrient limitation at different elevations, (b) physiological and morphological responses of trees to N and/or P addition, (c) the relationship of tree diversity and stand productivity, respectively, to nutrient availability, and (d) the effect of elevation on the relationships in (b) and (c).
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Hermann Jungkunst, Christoph Leuschner
Duration: April 2005 - October 2009
Funded by: DFG (
Graduiertenkolleg 1086)
Aims of the project: The flux of water from the soil through the trees to the atmosphere shall be modelled in deciduous forests of 1, 3 or 5 tree species based on water flux measurements in soil and trees, and controlling parameters investigated in other subprojects of the Graduiertenkolleg 1086. The main objective of the modelling effort is to understand the effect of tree species diversity on water fluxes in forests. Methods: Adaptation of existing modelling tools for describing water fluxes in soil and tree to the specific situation of theHainich forest with stands of 1, 3 or 5 tree species.
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Inga Schmidt, Christoph Leuschner
Duration: April 2005 - October 2009
Funded by: DFG (
Graduiertenkolleg 1086)
Aims of the project: For various forest stands in the study area, ownership, historical development and forest utilisation history shall be investigated for the past centuries. From historical stem growth chronologies, stand dynamics and interspecific competition processes will be analysed in order to understand the long-term development of stands with 1, 3 or 5 tree species. Methods: The historical development of the stands shall be investigated based on surveys of old maps, written notes from archives and records from former forest inventories. Stem cores will be analysed for annual growth ring width; the influence of drought and nutrition on growth is assessed by isotope and nutrient analyses in the growth rings.
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Tobias Gebauer, Viviana Horna, Christoph Leuschner
Duration: April 2005 - October 2009
Funded by: DFG (
Graduiertenkolleg 1086)
Aims of the project: Analysis of water consumption in forests with 1, 3 or 5 tree species for assessing the effect of tree species diversity on the water cycle in forests. Methods: Measurement of water flux in trees and canopy water loss with xylem sap flow and porometry in the canopy. For canopy access, a mobile canopy lifter is available. Use of stable isotopes for tracking the flow path of water in the soil-tree-atmosphere system.
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Catharina Meinen, Dietrich Hertel, Christoph Leuschner
Duration: April 2005 - October 2009
Funded by: DFG (
Graduiertenkolleg 1086)
Aims of the project: Investigating the role of tree species diversity on the size and structure of the fine root system and its carbon turnover (root growth and mortality) in forests with 1, 3 and 5 tree species. Methods: Modern techniques of rhizosphere research shall be applied including rhizoscopes, ingrowth cores and 14C-AMS-dating. The data are analysed in order to calculate total forest productivity (below- and aboveground) as a function of tree diversity.
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Mascha Jacob, Frank M. Thomas
Duration: April 2005 - October 2009
Funded by: DFG (
Graduiertenkolleg 1086)
Aims of the project: Investigation of the role of tree species diversity for the production of above-ground biomass, nutrient pools and exploitation of soil nutrient resources and nutrient cycling. Methods: Measurement of wood and leaf production, leaf area index, nutrient uptake, litter decomposition, nutrient concentrations in biomass and soil.
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Andreas Jacob, Dietrich Hertel, Christoph Leuschner, Matthias Schaefer
Duration: April 2008 - April 2011
Funded by: DFG (
Graduiertenkolleg 1086)
Aim of the project: Sub-project B2 analyses effects of various tree species composition on fine root biomass and root growth in mature forests. The investigations will be conducted in 100 tree clusters consisting of three tree individuals representing various combinations of five tree species abundant in the Hainich forest. Moreover, studies on tree species-specific fine root activity (growth, C sequestration, N uptake) will be done. Additionally, the susceptibility to herbivory of the fine roots of different species will be analysed in a mesocosm experiment. Methods: Differentiation of fine roots of various tree species, ingrowth core technique, Rhizoscopy (e.g. root windows, WinRhizotron software), Analysis of stabile isotopes (13C-AMS dating, 15N tracer and labelling), Mesocosms.
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Friderike Beyer, Dietrich Hertel, Christoph Leuschner
Duration: April 2008 - April 2011
Funded by: State of lower Saxony (Ministry of Science and Culture (
1b-Excellencecluster)
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Ann Catrin Fender, Dirk Gansert, Christoph Leuschner
Duration: April 2008 - April 2011
Funded by: State of lower Saxony (Ministry of Science and Culture (
1b-Excellencecluster)
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Laura Rose, Dietrich Hertel, Christoph Leuschner
Duration: April 2008 - April 2011
Funded by: State of lower Saxony (Ministry of Science and Culture (
1b-Excellencecluster)
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Annika Müller, Viviana Horna, Christoph Leuschner
Duration: April 2008 - April 2011
Funded by: State of lower Saxony (Ministry of Science and Culture (
1b-Excellencecluster)
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Benjamin Krause, Karsten Wesche, Heike Culmsee, Christoph Leuschner
Duration: April 2008 - April 2011
Funded by: State of lower Saxony (Ministry of Science and Culture (
1b-Excellencecluster)
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Jürgen Homeier, Malte Unger, Christoph Leuschner
Duration: January 2005 - June 2009
Funded by: BMBF (
ProBenefit)
The Convention on Biological Diversity (CBD) adopted at the Earth Summit of Rio de Janeiro in 1992 regulated access to biological resources. The Convention was signed by nearly all UN Member States, including Ecuador and Germany. By promoting ProBenefit the Federal German Ministry for Education and Research (BMBF) is making a contribution to implementing this international agreement. The goal of ProBenefit is to develop a suitable procedure for equitable benefit-sharing for the use of biological resources and the associated indigenous knowledge in line with the principles of the CBD. To this end the project partners, together with the Ecuadorian government, the local Indian organisations and other relevant groups in society, as well as interested non-governmental organisations, will explore new models for sustainable use of biodiversity in the Ecuadorian Amazon region. Our department conducts the fundamental botanical and ecological survey in the study area as a basis of future drug discovery in local medicinal plants.
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Benjamin Köckemann, Holger Buschmann, Christoph Leuschner
Duration: January 2004 - December 2007
Funded by: Helmholtz Association of National Research Centres (
VIMO)
The realised niche of a plant species is variable and may change towards the edge of a species' distribution range. This project analyses the niche of several abundant and several rare tree species in the centre of its distribution range (C Germany) and at its eastern limits (Eastern Europe). Among the environmental factors analysed are soil pH, base saturation and soil moisture. A number of stress indicators will also be investigated. It is aimed to quantify the niche breadth of these species and to investigate a possible niche shift between Central and Eastern Europe.
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Dirk Gaul, Dietrich Hertel, Christoph Leuschner
Duration: April 2005 - March 2007
Funded by: DFG (
Forschergruppe 562)
Fine root vitality and turnover in their response to experimental drought and soil freezing will be investigated in a replicated experiment in the Fichtelgebirge/Bavaria in a spruce stand. Root dynamics are studied by various approaches including rhizoscopes, root windows, soil coring, 14C-dating of root age and analysis of soluble carbohydrates in the roots. The project is part of an interdisciplinary research team including experts from soil chemistry and soil biology, hydrology, soil microbiology and trace gas measurement.
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Gabriele Krisinger, Dietrich Hertel, Christoph Leuschner
Duration: April 2008 - March 2011
Funded by: DFG (
Forschergruppe 562)
Fine root vitality and turnover and their response to experimental drought will be investigated in a Norway spruce stand in the Fichtelgebirge/Bavaria.
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Boris Rewald, Jhonathan E. Ephrath
Duration: November 2008 - February 2009
Funded by: European Union (FP6,
SSA Dryland Research)
Despite a detailed understanding of salt tolerance and avoidance mechanisms on molecular and physiological levels, and numerous experimental studies on the salt tolerance of herbaceous crops and tree seedlings, our understanding of salt tolerance mechanisms of adult trees or woody crops is still very limited. Salt tolerance mechanisms on the physiological level include salt exclusion, excretion and compartmentation, and are often associated with active osmotic adjustment, and conservative water use. Although roots are the first organs to be affected by salt stress, most research on salt tolerance focussed on aboveground organs but neglected morphological and physiological responses of the roots, especially in woody plants. This is astonishing because important processes of plant salt tolerance are thought to be located in the roots. Plasticity of the hydraulic system is still far less understood than altered growth pattern, salt-exclusion, or osmoregulation mechanisms. Photosynthesis and growth of plants in general, and olive trees in particular, are to a considerable degree determined by the plant’s hydraulic conductance. Understanding the forces and resistances that control the movement of water through the soil–plant system is essential in order to understand the influence of salinity on plant survival. The stem xylem vessels of halophytic or at least more salt-tolerant trees are more numerous and narrower than those in mesophytic trees or can completely change in type. Far less is known about the influence of salinity on root systems, although it has been demonstrated that differences in growth reduction caused by salt stress are the result of differences in root system structure or salt exclusion capacities. Previous studies pointed to the importance of functionally differentiated root systems for water acquisition in heterogeneously saline soils and the importance of morphological adjustments and functional differentiation within the axial root hydraulic system at two levels of organisation: at a vascular level within an individual root (conduit size distribution) and between roots at the level of organ (diversification of roots with contrasting conductivities and ‘high conductivity’ roots). Thus, a high plasticity of the axial root hydraulic system seems to be an effective mechanism in adaptation to salinity. However, the knowledge about other restrictions of water uptake and water transport due to salt stress, e.g. by a modified radial root conductivity, and a possible increased xylem sap salinity (which is negative correlated with axial conductivity), is scarce and subject to further research.
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Stefan Meyer, Christoph Leuschner
Duration: May 2007 - October 2008
Funded by: DBU (
Schutzäcker)
Das Projekt "Errichtung eines bundesweiten Schutzgebietsnetzes für Ackerwildkräuter" verfolgt das Ziel, ein nachhaltiges Schutzgebiets-Netzwerk zum Erhalt bedrohter Segetalarten in Deutschland zu konzipieren und umzusetzen. Eine Anzahl von mindestens 100 geeigneten Ackerstandorten soll für eine "dauerhafte Sicherung" selten gewordener Ackerwildkräuter unter Schutz gestellt werden und ihre spezielle, auf den Erhalt und Förderung der entsprechenden Arten ausgerichtete Bewirtschaftung langfristig sichergestellt werden. Mit dem Projekt besteht erstmals die realistische Chance, langfristig dem seit Jahrzehnten unvermindert voranschreiten Artenschwund der Ackerwildkräuter durch ein Netz von Schutzflächen zu begegnen. Das Vorhaben gliedert sich in eine Machbarkeitsstudie und die darauf aufbauende Umsetzungsphase als "Hauptprojekt". In der auf die Laufzeit von 18 Monaten beschränkten Machbarkeitsstudie sollen Strategien und Lösungen entwickelt werden, so dass zum Beginn der folgenden Umsetzungsphase Konzepte vorliegen, die eine langfristige Finanzierung und die für den Erhalt der seltenen Arten notwendige extensive Bewirtschaftung sicherstellen können.
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Stefan Meyer, Christoph Leuschner
Duration: September 2006 - September 2009
Funded by: Helene und Rudolf Glaser Stiftung (
Schutzäcker)
Von dem Projekt soll ein neuer Impuls zur nachhaltigen Einrichtung und Bewirtschaftung von Schutzäckern mit dem Ziel des Erhaltes einer vielfältigen Ackerwildkraut-Vegetation ausgehen. Ziele dabei sind die Entwicklung und Erprobung eines praxistauglichen Konzeptes zum dauerhaften Erhalt überlebensfähiger Ackerwildkraut-Populationen in der Agrarlandschaft, die Erfolgskontrolle des Schutzprogramms mittels Vegetationsanalyse und Populationsgrößen-Ermittlung und die Optimierung des Schutzprogramms in ökonomischer Hinsicht. Als Ausgangspunkt für ein angestrebtes bundesweites Netz an Schutzäckern konzentriert sich das Vorhaben auf Mitteldeutschland: auf den Süden Niedersachsens, das nördliche Hessen sowie den Westteil Thüringens und Südwesten Sachsen-Anhalts. Hier finden sich Refugien einer artenreichen Ackerwildkraut-Vegetation, insbesondere auf flachgründigen Kalkstandorten.
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Boris Rewald, Jhonathan E. Ephrath
Duration: November 2006 - 2007
Funded by: European Union (
FP6)
In the last decades, some studies have started to analyse the influence of salinity induced water stress on aboveground hydraulic properties. The stem xylem vessels of halophytic or at least more salt-tolerant trees are more numerous and narrower than those in mesophytic trees or can completely change in type. Its well known from drought stressed plants that this could reduce the probability of cavitation, but the increasing flow resistances may also result in lower rates of water uptake. Until now it is not clear, if those reduced conductivity rates are only negative effects of increased xylem water tension, could even minimize water consumption or help to reduce salt accumulation in leaves. Far less is known about the influence of salinity on root morphology and root hydraulic properties. In general, root hydraulic conductivities are decreasing with increasing salinity, but there is first evidence that roots of different genotypes could react very different on salt stress. The plasticity of the responses of root hydraulic conductivity and xylem vulnerability to cavitation and their influence on salt tolerance is far less understood than salt exclusion or osmoregulation mechanisms. Olea europaea L. is to be chosen as a study object because the cultivation of olives is highly encouraged in the Mediterranean countries because of its limited water requirement. Olives are often irrigated with saline water, especially in coastal areas, but different cultivars vary strongly in their salt tolerance. Initial data on olives root morphology using the minirhizotron technique were already obtained in a long-term experiment which is conducted in the Ramat-Negev experimental station (Negev desert, Israel). Data were collected from several varieties and at two levels of salinity (1.0 and 4.2 ds m-1). The major goal of this study will be to examine the role of the rooting system, especially in respect of hydraulic conductivity and vulnerability to embolism, in salt tolerance of three different salinity sensitive olive varieties 'Proline', 'Picual' and 'Barnea' at the same salinity levels (1.2 and 4.2 ds m-1). Root cross-sections should be examined anatomically in regard to effective conductivity areas and vessel diameter distributions concerning theoretical and specific conductivity rates and dependence of embolism rates on vessel diameter distribution.
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Stefan Fleck, Christoph Leuschner
Duration: September 2005 - June 2008
Funded by: AiF (Projektträger des BMWi)
The project aims to develop a new integrated system for automated canopy structure assessment and physiological modelling that is based on terrestrial laser-scanning. The system is developed and tested with integrated measurements of tree structure, light climate, photosynthesis, and transpiration in row plantations of apple and cherry trees. The approach is conducted by 3 partners and comprises 3 steps: 1. The 3D-laserscanner Imager 5003 (Zoller + Fröhlich GmbH, Wangen) is used to acquire 3D-point clouds from multiple view positions in order to represent canopy structure of single trees. The combination with a camera shall enable colour discrimination between points originating from branches, leaves and fruits. 2. Coloured point clouds are automatically segmented and canopy elements are approximated by surface functions (TU Delft). Allometric relationships to branch cross-sectional area will be employed to check plausibility of the resulting structure representation. 3. The structure representation is integrated with a 3D-light-model (University of Göttingen, compare Fleck et al. 2004). Light acclimation of all single leaves is modelled based on measured relationships and a model of photosynthesis and transpiration will be employed on the leaf scale. Validation measurements of leaf photosynthesis, light acclimation, and branch transpiration are used to test the combined model of structure, light, and physiology on different levels of spatial integration.
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Jasmin Lendzion, Christoph Leuschner
Duration: June 2004 - May 2007 (completed)
Funded by: DBU
According to climate change the risk of summer droughts in large parts of Central Europe will rise, because of decreased or missing precipitations during the summer. Decreased precipitation and increased temperature could cause a higher vapour pressure deficit of the air (vpd), which might affect terrestrial ecosystems that are adapted to humid conditions. One of these ecosystems is the forest floor which represents a unique environment with low light input, damped temperature fluctuations, and generally high air humidity. Hence, woodland herbs growing in this micro climate have adapted to these conditions. While several studies have investigated light, soil water, and soil chemistry as ecological factors of the forest floor environment, the influence of air humidity or the vpd has received little attention. The study wants to examine long-term effects of different air humidity levels (independently from other factors) on physiology and productivity of woodland herbs and tree saplings of a temperate deciduous broad-leaved forest by manipulating atmospheric moisture (a) in climate chambers, and (b) in open-top chamber experiments on the forest floor. The study aim is to test the hypothesis that air humidity is an independent ecological factor for the forest floor vegetation and that reduced air humidity exerts a negative effect on physiology and productivity on several species of the understorey vegetation of temperate forests.
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Boris Rewald, Christoph Leuschner
Duration: June 2004 - May 2007
Funded by: Stiftung der Deutschen Wirtschaft (SDW)
Although the water availability represents one of the most important factors of trees, the water absorption of roots ranks, for methodical reasons, among the fewest investigated scopes of the ecophysiology. Especially the influence of drying stress on the fine root systems of Central European tree species is unknown. This is even more amazing, as in several studies it was shown that the annual production and the turnover of the fine roots can use more than half of annually fixed carbon. In consideration of the prognosticated rise in temperature and arising summer dryness due to global climatic heating it is ecologically and forest-economically important to obtain insights over the effect of soil dryness on the fine root system of major Central Europe tree species. Today it is largely unsettled whether the effect of drying stress on different age stages differs. A goal of the planned study is to analyze the effect of dryness on the fine root system of three different age stages (seedlings, young trees and old ees) of Fagus sylvatica and Quercus petraea. Comparing investigations are planned to investigate the fine root morphology, the root growth as well as the carbon allocation of the entire individual at all three age stages. In addition, measurements of the xylem water potential, the current cavitation and the vulnerability to cavitation as well as the anatomical structure of the periderm and the xylem are done. Through comparisons it should be estimated, if (1) ontogenetic stages differ in their root-physiological reactions to drying stress, (2) from which degree of soil drainage young and/or old beeches and oaks are lastingly damaged, and (3) whether the carbon allocation of different ontogenetic stages differs from beech and oak with same water availability.
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Ina C. Meier, Christoph Leuschner
Duration: December 2003 - November 2006 (completed)
Funded by: DBU
Neben den Parametern Nährstoffversorgung und Temperatur stellt die Wasserverfügbarkeit einen der wichtigsten Standortsfaktoren dar, die das Wachstum von Bäumen beeinflussen. Während über die Auswirkungen eingeschränkter Wasserversorgung auf die Physiologie und das Wachstum der oberirdischen Kompartimente von Altbäumen bereits eine Vielzahl von Untersuchungen vorliegen, ist über den Einfluss von Trockenstress auf das Feinwurzelsystem mitteleuropäischer Baumarten bislang erst wenig bekannt. Dies ist umso erstaunlicher, als in mehreren Studien gezeigt wurde, dass die jährliche Produktion und der Umsatz der Feinwurzeln mehr als die Hälfte des in der Krone assimilierten Kohlenstoffs einnehmen kann. Im Hinblick auf die prognostizierte Temperaturerhöhung infolge der globalen Klimaveränderung ist es daher von ökologischer wie auch forstwirtschaftlicher Bedeutung, Erkenntnisse über die Auswirkung von Trockenheit auf das Feinwurzelsystem wichtiger Waldbaumarten in Mitteleuropa zu gewinnen. Ziel der geplanten Studie ist es, die Wirkung von Trockenheit auf die Biomasse des Feinwurzelsystems der Rotbuche (Fagus sylvatica L.) in verschiedenen Altbeständen entlang eines natürlichen Niederschlagsgradienten in Mitteldeutschland zu untersuchen. In experimentellen Ansätzen im Freiland sowie im Rhizolab (Wurzellabor) der Universität Göttingen soll weiterhin der Einfluss von eingeschränkter Bodenwasserverfügbarkeit auf das Wachstum von Feinwurzeln der Rotbuche analysiert werden. In diesen Untersuchungen soll die Beziehung zwischen der Niederschlagsmenge (bzw. der Bodenwasserverfügbarkeit) und den Parametern Bestandesbiomasse, Tiefenverteilung, Wachstum und Mortalität der Buchenfeinwurzeln untersucht werden, um Anpassungsmechanismen und limitierende Umweltfaktoren dieser in Mitteleuropa forstwirtschaftlich sehr bedeutenden Baumart zu ermitteln.
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Annika Frech, Christoph Leuschner
Duration: February 2003 - January 2006 (completed)
Funded by: DBU
Ziel der Untersuchung ist die Prognose der künftigen Veränderung der Baumartenzusammensetzung in den Mischwäldern des Nationalparks Hainich sowie die Übertragung der Ergebnisse auf praxisrelevante Fragen einer nachhaltigen forstlichen Behandlung von Mischbeständen. Dazu wird auf vier Kernflächen (0.64 ha) die dreidimensionale Bestandesstruktur analysiert, um Nachbarschaftsmuster im Hinblick auf die artspezifische Besetzung des Kronenraums, auf den Totholzanteil, sowie die Häufigkeit und Altersstruktur der Verjüngung erfassen zu können. Ein besonderer Schwerpunkt liegt bei der Untersuchung der Interaktionsprozesse im Kronenraum, der mittels einer mobilen Hebebühne zugänglich gemacht wird. Durch Trieblängenrückmessungen, Astwinkel- und Strahlungsmessungen an den werden die Mechanismen der Kronenraumeroberung untersucht. Darüber hinaus werden an ausgewählten Bäumen der untersuchten Arten (Rotbuche, Winterlinde, Hainbuche und Esche) dendroökologische Untersuchungen durchgeführt. Mit einer GIS-gestützten Verknüpfung der Ergebnisse aus den Einzeluntersuchungen sollen Aussagen über die Konkurrenzstärke der untersuchten Baumarten und über zu erwartende Artenverschiebungen abgeleitet werden.
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Dietrich Hertel
Duration: 2003-2005 (completed)
Funded by: BMBF
In three elevational transects in the central and southern Andes of Argentina, microclimate, stem growth, fine root biomass and fine root activity with respect to water absorption are investigated. The three transects cover regions with a semi-dry (in the North) to wet climate (in the South). Study objective is to understand the causes of the upper tree line in the Nothofagus forests. The study is conducted in co-operation with Argentinean dendrochronologists (R. Villalba).
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Ute Luginbühl, Helge Bruelheide
Duration: 2002-2005
Funded by: DFG
This study focuses on the floristic composition and development of the forest herb layer after wind throw in the nature reserve "Gipskarstlandschaft Hainholz" (Lower Saxony, Germany), an old and structurally diverse beech forest. The main research question is: Which is the most important factor for determining secondary succession and floristic diversity after wind throw - disturbance intensity or pre-disturbance state? Analyses revealed that the pre-disturbance state contributes more to explaining floristic composition and species diversity than disturbance intensity.
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Doris Burk, Heinz Coners, Christoph Leuschner
Duration: August 2002 - July 2004 (completed)
Funded by: DFG
Water uptake by tree fine roots under field conditions is not well understood. Using miniature sap flow gauges, we measure sap flux of beech, birch and pine in the undisturbed rhizosphere in two mixed stands with contrasting rainfall and soil moisture regimes (Northern Hesse: moist, Western Sachsen-Anhalt: dry). We also analyse morphological and chemical properties of the roots, which may be important in controlling the radial flux through the root periderm. Study objective is to examine possible differences in root hydraulic properties of drought-sensitive and drought-resistant tree species, and to search for evidence of adaptation processes in fine roots to drought.
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Dietrich Hertel
Duration: 2004 (completed)
Funded by: DFG
A transect study was conducted in various upper montane and tree line forests in the high Andes of Eastern Bolivia for analysing patterns of fine root abundance close to the upper reaches of the forest. Simultaneously, microclimate, forest structure and regeneration were investigated along this elevational transect.
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