Das Projekt "Gene flow and sex ratio of Populus euphratica Oliv. floodplain forests at the Tarim River, Xinjiang, NW China" wird vom Umweltbundesamt gefördert und von Ernst-Moritz-Arndt-Universität Greifswald, Biologie, Institut für Botanik und Landschaftsökologie durchgeführt. In extension of a previous project dedicated to study the genetic diversity of the so-called Tugai forests in the extremely arid Tarim basin of Chinas Xinjiang province, we want to investigate reproductive biology and the performance of sexes in Populus euphratica, as well as the gene flow between stands to explain the high degree of genetic diversity distributed within stands. This should allow deriving sound recommendations for a conservation strategy of the Tugai forests. In addition, we want to extent the existing body of data on mapped and genotyped old-growth stands to derive a sex aggregation index and show its usefulness for estimating stand clonality by comparison with the clonality index derived from microsatellite genotyping. Due to a change of methods for genotyping (from AFLP to a high-throughput microsatellite multiplex PCR) we saved money to genotype three more stands. This will provide consumables for one Ph.D. student (currently payed by a scholarship from the state of Mecklenburg-Western Pomerania) to complete her Ph.D. thesis.
Das Projekt "Water use characteristics of bamboo (South China)" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Burckhardt-Institut, Abteilung Waldbau und Waldökologie der Tropen durchgeführt. Bamboos (Poaceae) are widespread in tropical and subtropical forests. Particularly in Asia, bamboos are cultivated by smallholders and increasingly in large plantations. In contrast to trees, reliable assessments of water use characteristics for bamboo are very scarce. Recently we tested a set of methods for assessing bamboo water use and obtained first results. Objectives of the proposed project are (1) to further test and develop the methods, (2) to compare the water use of different bamboo species, (3) to analyze the water use to bamboo size relationship across species, and (4) to assess effects of bamboo culm density on the stand-level transpiration. The study shall be conducted in South China where bamboos are very abundant. It is planned to work in a common garden (method testing), a botanical garden (species comparison, water use to size relationship), and on-farm (effects of culm density). Method testing will include a variety of approaches (thermal dissipation probes, stem heat balance, deuterium tracing and gravimetry), whereas subsequent steps will be based on thermal methods. The results may contribute to an improved understanding of bamboo water use characteristics and a more appropriate management of bamboo with respect to water resources.
Das Projekt "Clustered Subsampling of Double Sampling for Stratification and Growth Model Based Updates of Past Forest Inventories" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Büsgen-Institut, Abteilung Ökoinformatik, Biometrie und Waldwachstum durchgeführt. Double Sampling for Stratification is a sampling design that is widely used for forest and resource inventories worldwide and, particularly, well established for periodic forest inventories of districts in public and private forests in Germany. Spatially clustered subsampling of second-phase units, actually representing a third phase of sampling, can be expected to reduce travelling costs, but will also decrease precision of estimates. Therefore, the proposed project is intended to develop estimators for totals and per hectare values of usual target variables in forest inventories as well as related sampling errors under that new three-phase sampling design. Using real data the trade-off between precision and amount of clustering will be analyzed. A special focus will be on temporary regional or state-wide inventories based on previous double sampling district inventories. In this case additional precision can be gained by updating the previous inventories using growth models. These growth predictions shall be combined with the sample based estimator to form a composite estimator of higher precision.
Das Projekt "Entwicklung von DNA-Markern im Kerngenom der Fichte (Picea abies L. Karst) zur Analyse der genetischen Variation und zum Nachweis von Inzucht in Waldbeständen" wird vom Umweltbundesamt gefördert und von Technische Universität München, Lehrbereich Forstgenetik durchgeführt. Ziel des Projektes ist die Fortsetzung der erfolgreich begonnenen Entwicklung von DNA-Markern im Kerngenom der Fichte und das Testen dieser Marker auf einer breiteren Basis. Testpopulationen sind insgesamt 15 autochthone Fichtenbestände, die einen großen Teil des Verbreitungsgebietes dieser Baumart abdecken. Die bisher erzielten Ergebnisse (s. separaten Bericht) zeigen, daß die neu entwickelten Marker besonders gut zum Nachweis genetischer Variation innerhalb von Populationen und zum Test auf Inzucht geeignet sind. Aus diesem Grund wurde die Zielsetzung des Fortsetzungsantrages entsprechend erweitert. Zusätzlich werden alle neu entwickelten Genmarker zusammen mit konventionellen Isoenzym-Genmarkern zu einer Genkarte zusammengefügt. Damit sollen Voraussetzungen für den Nachweis von Korrelationen zwischen Genmarkern und phänotypischen Merkmalen sowie für die Nutzung im Rahmen markergestützter Selektion geschaffen.
Das Projekt "Regulation der N2-Freisetzung aus sauren Waldböden" wird vom Umweltbundesamt gefördert und von Universität Göttingen, Büsgen-Institut, Abteilung Ökopedologie der Tropen und Subtropen durchgeführt. Ziel des Vorhabens ist es, die Rolle des Aziditätsgrades von Waldböden, der O2-Diffusion bei unterschiedlichen Wassergehalten, der Temperatur und des Nitrat-Vorrates auf die Menge und Zusammensetzung der emittierten N-Gase zu ermitteln und die daran beteiligten Prozesse modellhaft zu beschreiben. Durch die mit Isotopenmethoden mögliche Ermittlung der Einzelkomponenten der N-Emissionen, lassen sich Rückschlüsse auf die beteiligten Prozesse und ihre Umsatzraten ziehen. Bisher konnten wichtige Teilziele bearbeitet werden: der Einfluß der Bodenazidität auf die Emission von N2 und N2O, sowie auf die Prozesse der N2O Bildung; der Einfluß der Saisonalität auf die Prozesse der N2O Bildung am Beispiel eines saisonalen Emissionstyps. In dem auf 3 Jahre geplanten Vorhaben konnten bisher andere, wesentliche Steuergrößen nicht untersucht werden. Zu diesen Steuergrößen zählen der Wassergehalt, der Nitratgehalt und die Bodentemperatur. Der Einfluß dieser Größen auf die N2 und N2O Emissionen soll im Rahmen des beantragten Fortsetzungsvorhabens untersucht werden.
Das Projekt "Methods used in paleobotany and paleoentomology for the investigation of post-glacial forest history" wird vom Umweltbundesamt gefördert und von Technische Universität Dresden, Institut für Forstbotanik und Forstzoologie, Professur für Forstbotanik durchgeführt. The historical evolution of forest ecosystems can be reconstructed by means of the dendrochronological and dendroecological tree-ring analysis of deceased and living trees. Characteristical tree-ring patterns enable the building of chronologies for several decades to centuries to comprehend the development of a forest stand. Single impacts like storms, drought, floodings, late frost or insect calamities can often be tracked in tree rings. Such analyses are possible only by means of climatical data or historical sources. Methods and techniques of paleoecology and paleobotany can provide farther evidence of forest history. By the use of macrofossiles like fruits, seeds and wooden parts as well as microfossiles like pollen and spores the evolution of plant communities can be analysed. Dating of charcoal findings and fire scars on old tree stumps allows the reconstruction of regionally important forest fires in the past. Further a combination of paleobotanical and paleoentomological techniques using pollen and fossile insects can document the historical insect population together with the plant species composition. In Sweden the profound analysis of the postglacial development of forest ecosystems is still possible
Das Projekt "Regeneration in an Ethiopian montane forest with special emphasis on tree biology and nurse-tree functions" wird vom Umweltbundesamt gefördert und von Universität Bayreuth, Fachgruppe Biologie, Bayreuther Zentrum für Ökologie und Umweltforschung (BayCEER), Lehrstuhl für Pflanzenphysiologie durchgeführt. In the Munessa-Sheshamene region (Ethiopia) several plots of moderately disturbed natural forest and of exotic tree plantations have been investigated with respect to water relations and photosynthetic capcity of selected indigenous and exotic trees. This ongoing work is part of an ecosystem study conducted by soil scientists, geobotanists and plant ecophysiologists that aims at a scientific basis for a sustainable management of the Munessa forest as a model for other semideciduous forests of Ethiopia. The work shall be continued in two working packages, one of which will investigate the so-called nurse-tree effect. Juveniles of indigenous trees developing from seeds that accidentally arrived in a plantation of Eucalyptus saligna, E. globulus or Pinus patula grow significantly faster under the shelter of these 'nurse-trees' than in a natural forest. This unexpected nurse-tree effect will be studied in plantations with a successful regeneration of indigenous trees. In the second working package, regeneration ecology of important indigenous tree species will be studied, comprising modes of regeneration, regenerative capacity and the effective regeneration success under natural and plantation situations.
Das Projekt "The fate of phosphorus in forest and treeline ecosystems in Ecuador" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Fachbereich Geowissenschaften, Forschungsbereich Geographie durchgeführt. Even remote areas such as tropical montane forests suffer from continuously high atmospheric nitrogen (N) and phosphorus (P) deposition. In studies on ecosystem responses to atmospheric nutrient deposition, P cycling has played an underrated role compared to N, although P is thought to limit organism growth in main parts of the Tropics. Furthermore, the responses of tropical montane forests to atmospheric nutrient deposition might depend on the predicted climate change i.e., shifts in temperature and precipitation. Altitudinal gradients represent an ideal means to study environmental changes in tropical montane forests in southern Ecuador, because climate scenarios and unpublished trends in longer-term climate data predict increasing temperatures and decreased moisture which parallels the altitudinal gradient from 4000 m to 1000 m asl.Previous experiments, including the NUMEX experiment in Ecuador, showed that the main proportion of P added to forests to simulate atmospheric deposition was retained in soil. While total P pools in soil respond slowly to low P addition rates, the biological and geochemical processes underlying retention in the organic layer or in soil are expected to react faster. Our overarching objective is to assess the fate of fertilized P in the organic layer and in mineral soil and to elucidate the processes involved in P cycling in soil (immobilization and release rates by microorganisms, sorption/desorption, precipitation/dissolution) along the NUMEX-X altitudinal gradient (1000, 2000, 3000, 4000m; the latter including a Polylepis and a Páramo ecosystem). We will assess P fractions in soil and use a combination of 33P tracer studies and incubation experiments to disentangle biological and geochemical processes controlling P retention. The mechanistic understanding gathered by this proposal is crucial for predictions of ecosystems responses to the continuously high atmospheric N (and P) deposition, because single mechanisms might respond differently (and oppositionally) in the long run. Because the processes involved in P cycling are expected to respond faster to environmental changes than e.g., P pools in soil, these different responses are an essential basis to evaluate effects of environmental change and finally, to develop early-warning ecosystem indicators for environmental change.
Das Projekt "The role of gap dynamics for the regeneration of the natural spruce forests in the Harz Mountains" wird vom Umweltbundesamt gefördert und von Martin-Luther-Universität Halle-Wittenberg, Biowissenschaften - Institut für Biologie, Institutsbereich Geobotanik und Botanischer Garten durchgeführt. In Central Europe only few places are known where vegetation regeneration after natural disturbances can be studied in natural or near-natural Picea abies forests; one example are the slopes of Mt. Brocken. Although being mono-dominant, the spruce forests at Mt. Brocken are unique because they contain autochthonous Picea abies genotypes. In addition, the herb layer is comparably species-poor with a high proportion of clonally reproducing species. Based on the assumption that gap dynamics are equally important for regeneration of the tree and herb layer as in other forest types, the project seeks to test four main hypotheses. For the tree layer, it will be tested whether gaps promote the establishment of allochthonous genotypes of Picea abies and whether the proportion of autochthonous genotypes increases with gap age due to strong environmental selection. For herb layer regeneration the hypotheses are tested that generative reproduction is enhanced in gaps for the abundant clonal species Vaccinium myrtillus, Calamagrostis villosa and Trientalis europaeus and that clone size increases with gap age. To attain its goal the project employs GIS, dendrochronology and molecular genetic approaches. Using aerial photographs, gaps will be stratified according to age and sampled for species composition and population structure of target species. The field observations will be supplemented by experiments on establishment, frost hardiness and vegetative regeneration capacity of spruce as well as on clonal growth of target herbs.
Das Projekt "Can the resistance and resilience of trees to drought be increased through thinning to adapt forests to climate change?" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Waldbau-Institut durchgeführt. Recent and predicted increases in extremely dry and hot summers emphasise the need for silvicultural approaches to increase the drought tolerance of existing forests in the short-term, before adaptation through species changes may be possible. We aim to investigate whether resistance during droughts, as well as the recovery following drought events (resilience), can be increased by allocating more growing space to individual trees through thinning. Thinning increases access of promoted trees to soil stored water, as long as this is available. However, these trees may also be disadvantaged through a higher transpirational surface, or the increased neighbourhood competition by ground vegetation. To assess whether trees with different growing space differ in drought tolerance, tree discs and cores from thinning experiments of Pinus sylvestris and Pseudotsuga menziesii stands will be used to examine transpirational stress and growth reduction during previous droughts as well as their subsequent recovery. Dendroecology and stable isotopes of carbon and oxygen in tree-rings will be used to quantify how assimilation rate and stomatal conductance were altered through thinning. The results will provide crucial information for the development of short-term silvicultural adaptation strategies to adapt forest ecosystems to climate change. In addition, this study will improve our understanding of the relationship between resistance and resilience of trees in relation to extreme stress events.
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