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.
This project focuses on the long-term stability (or otherwise) of vegetation, based on a series of multi-proxy records in southern South America. We will build a network of sites suitable for high-resolution reconstructions of changes in vegetation since the Last Glacial Maximum, and use these to test a null hypothesis that changes in vegetation over the past 14,000 years are driven by internal dynamics rather than external forcing factors. The extent to which the null hypothesis can be falsified will reveal the degree to which we can expect to be able to predict how vegetation is affected by external events, including future climate change. The southern fringes of the South American landmass provide a rare opportunity to examine the development of moorland vegetation with sparse tree cover in a wet, cool temperate climate of the Southern Hemisphere. We present a record of changes in vegetation over the past 17,000 years, from a lake in extreme southern Chile (Isla Santa Inés, Magallanes region, 53°38.97S; 72°25.24W; Fontana, Bennett 2012: The Holocene), where human influence on vegetation is negligible. The western archipelago of Tierra del Fuego remained treeless for most of the Lateglacial period. Nothofagus may have survived the last glacial maximum at the eastern edge of the Magellan glaciers from where it spread southwestwards and established in the region at around 10,500 cal. yr BP. Nothofagus antarctica was likely the earlier colonizing tree in the western islands, followed shortly after by Nothofagus betuloides. At 9000 cal. yr BP moorland communities expanded at the expense of Nothofagus woodland. Simultaneously, Nothofagus species shifted to dominance of the evergreen Nothofagus betuloides and the Magellanic rain forest established in the region. Rapid and drastic vegetation changes occurred at 5200 cal. yr BP, after the Mt Burney MB2 eruption, including the expansion and establishment of Pilgerodendron uviferum and the development of mixed Nothofagus-Pilgerodendron-Drimys woodland. Scattered populations of Nothofagus, as they occur today in westernmost Tierra del Fuego may be a good analogue for Nothofagus populations during the Lateglacial in eastern sites. Climate, dispersal barriers and/or fire disturbance may have played a role controlling the postglacial spread of Nothofagus. Climate change during the Lateglacial and early Holocene was a prerequisite for the expansion of Nothofagus populations and may have controlled it at many sites in Tierra del Fuego. The delayed arrival at the site, with respect to the Holocene warming, may be due to dispersal barriers and/or fire disturbance at eastern sites, reducing the size of the source populations. The retreat of Nothofagus woodland after 9000 cal. yr BP may be due to competitive interactions with bog communities. Volcanic disturbance had a positive influence on the expansion of Pilgerodendron uviferum and facilitated the development of mixed Nothofagus-Pilgerodendron-Drimys woodland.
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.
The aim of P2 within the Research Unit 'The Forgotten Part of Carbon Cycling: Organic Matter Storage and Turnover in Subsoils (SUBSOM)' is to contribute to the understanding of the different sources and stabilization processes of subsoil organic matter. This will be achieved by the analysis of the soil organic matter composition in topsoil versus subsoil by 13C NMR spectroscopy in bulk soils as well as organo-mineral associations. This will be done on a number of soil profiles differing in parent material and mineralogy and therefore also in the relevance of organo-mineral associations for subsoil C stabilization. In addition, a specific sampling approach will allow to differentiate three zones associated with the dominating effect of (1) leaching of DOC (the 'bulk soil' between trees), (2) root litter decomposition (the 'root-affected zone'), and (3) direct rhizodeposition of root exudates (the 'rhizosphere' sensu strictu). The contribution of above-ground versus below-ground litter is differentiated by the analysis of cutin and suberin biomarkers. Organic matter derived from microbial sources will be identified by the microbial signature of polysaccharides in the subsoil through the analysis of neutral sugars and amino sugars. Organo-mineral associations will be further characterized by N2-BET analyses to delineate the coverage of the mineral phase with organic matter. With these analyses and our specific analytical expertise at the submicron scale (nanoSIMS) we will participate in selected joint experiments of the research unit.
Research in 'silviculture' and 'forest economics' very often takes place largely independent from each other. While silviculture predominantly focuses on ecological aspects, forest eco-nomics is sometimes very theoretic. The applied bioeconomic models often lack biological realism. Investigating mixed forests this proposal tries to improve bioeconomic modelling and optimisation under uncertainty. The hypothesis is tested whether or not bioeconomic model-ling of interacting tree species and risk integration would implicitly lead to close-to-nature forestry. In a first part, economic consequences of interdependent tree species mixed at the stand level are modelled. This part is based on published literature, an improved model of timber quality and existing data on salvage harvests. A model of survival over age is then to be developed for mixed stands. A second section then builds upon data generated in part one and concentrates on the simultaneous optimisation of species proportions and harvest-ing ages. It starts with a mean-variance optimisation as a reference solution. The obtained results are compared with data from alternative approaches as stochastic dominance, down-side risk and information-gap robustness.
Das Projekt B1 'Allometrie und Raumbesetzung von krautigen und holzigen Pflanzen' ist Teil des Sonderforschungsbereiches 607 Wachstum und Parasitenabwehr und befindet sich bereits in der vierten Phase des seit 1998 laufenden Forschungsprojektes. Bisher wurde im Projekt B1 die Allometrie als Resultat der pflanzeninternen Steuerung der Allokation untersucht. Auf Individuenebene wurden Allometrie und ihre Veränderung für verschiedene Baumarten in verschiedenen ontogenetischen Stadien untersucht. Auf Bestandesebene wurden die self-thinning-Linien von Yoda und Reineke für krautige bzw. holzige Pflanzenbestände analysiert. Bisherige Allometriebestimmungen erbrachten für diese Arten zwar ähnliche Größenordnung aber auch charakteristische Unterschiede, die Ausdruck spezifischer Strategien der Raumbesetzung und -ausbeutung widerspiegeln. Die bisher vereinzelten Auswertungen sollen in Phase IV in eine übergreifende Analyse (versch. Arten, ontogenetische Stadien, Konkurrenzsituationen, Störfaktoren) der Allometrie auf Pflanzen- und Bestandesebene münden.
Calcium supply in tropical soils is variable and frequently low. In spite of the heterogeneous Ca supply, some plant species, such as figs, maintain high Ca concentrations in their tissues. Figs are keystone species with more than proportional importance for the functioning of a tropical rain forest. High Ca concentrations in fig fruits may render them particularly attractive for frugivorous vertebrates. We propose to study the whole Ca cycling from soil through a selected fig species, Ficus insipida Willd. and frugivorous bats, their main dispersers, back to soil. The study will be conducted in Panama on sites differing in soil Ca status to assess the importance of soil Ca availability for fig fruit content and bat reproduction. We will quantify aboveground Ca fluxes for 16 trees along a gradient of Ca availability in soil. We will determine (1) Ca concentrations in soils, figs and leaves, (2) nutritional quality of fig and other bat-dispersed fruits and their importance for Ca balance in relation to reproduction of fruit-eating bats, (3) Ca fluxes with litterfall, throughfall, stemflow, bat pellets and faeces, (4) the importance of the contribution of bats to the Ca cycle of individual fig trees, and (5) the effect of fig trees on soil Ca concentrations.
Insect outbreaks are a major disturbance influencing forest dynamics in many ecosystems and can affect forest productivity worldwide. Reconstruction of insect outbreak history is fundamental to forest management. While the action of cambium feeders on trees leads to the formation of scars, that of defoliators is observable via growth suppression in tree rings. The occurrence of past insect attacks can thus be inferred from such tree-ring signatures. However, it necessitates an accurate dating of events, with high temporal resolution, as well as their correct attribution to the right disturbance agent. Fire also leaves scars on trees that can occur on cross-sectional disks where insect scars are already present, thus making them difficult to distinguish. Furthermore, insect-elicited reductions in radial growth may not be clearly visible on samples, and the radial growth response to defoliation often bears a lag of one or more years. This project tackles these issues directly by proposing a multi-proxy approach aiming at improving tree-ring reconstructions of insect outbreaks. Tree rings will be investigated to study radial variations of tree-ring width, wood anatomy, wood density, and wood chemistry. While dendrochronologists have long relied on tree-ring width variations to track the signal induced by climate, geomorphic and ecological processes, they have scarcely exploited the potential of other proxies and rarely used them in combination. The most advanced studies that have embraced these possibilities are owed to dendroclimatologists. The core of this research therefore lies in the use of multiple wood traits to provide answers to the above mentioned dendroecological questions. Two conifer tree species from British Columbia and their respective pests are within the scope of this study: the mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins), a cambium feeder, on lodgepole pine (Pinus contorta Douglas), and the western spruce budworm (WSBW, Choristoneura occidentalis Freeman), a defoliator, on Douglas-fir (Pseudotsuga menziesii Franco). It is hypothesized that insect outbreak disturbance in the form of bark beetle or defoliation events results in abrupt significant structural differences between the wood formed prior to and after the insect attack. Based on pioneering tree-ring research on insect outbreaks, there are great prospects that the variations of wood traits be proven useful for differentiating MPB scars from fire scars and for identifying WSBW defoliation events, possibly with higher temporal resolution. The study of multiple wood traits (proxies) will help gain an understanding of the influence of insect outbreak disturbance on wood formation and tree physiological processes, a prerequisite for improving the detection and dating of events in tree-ring series. (...)
Informationen der staatlichen Umweltverwaltung Mecklenburg-Vorpommern: Die naturräumliche Gliederung als Themenbereich im Kartenportal Umwelt M-V besteht aus folgenden hierarchischen Ebenen - Landschaftszonen - Großlandschaften - Landschaftseinheiten - Naturräume Die der Digitalisierung zugrundeliegende Fassung der naturräumliche Gliederung für Mecklenburg-Vorpommern wurde für den terrestrischen und marinen Bereich getrennt erarbeitet (vgl. Quellen) und im Jahr 2001 im Auftrag des LUNG durch die Firma Umweltplan zusammengeführt und an die Landesgrenzen und Küstenlinien der ATKIS-Basis-DLM (1. Realisierungsstufe) angepasst. Die Einzelthemen dieses Bereiches sind auch als WMS Naturräume verfügbar.
The number one question in ecology is why certain organisms occur where they do, and what the traits are which make them successful. This project aims at arriving at a mechanistic rather than a correlative explanation of the climatic limits of major European broad leaved tree taxa. It will focus on and explore their temperature-related limits and aims at reviving Europe's traditional strength in physiology based ecology by training a group of young scientists to answer such questions. The project builds upon the PIs experience in mechanism-oriented ecology (e.g., synthesis in Körner 2003) and should help trading those rapidly disappearing skills to a next generation of experimental ecologists. The project adopts a three-step approach: (1) Assess the current extreme postions of tree taxa along thermal gradients, using existing data bases and site visits (data mining, biogeography). (2) Associate those patterns with bioclimatic information, both available and newly acquired (climatology). (3) Empirically test hypotheses of causes of growth limitation and stress survival, both in the field and in the laboratory (ecophysiology). The project will account for ecotypic differentiation by using the marginal and central (optimal) positions of taxa and will explore plant establishment as well as adult plant performance. It will use in situ measurements, transplant and common gardens as well as phytotron testing. Genotypic control of phenology, frost hardiness, thermal constraints for shoot and root growth and reproductive system (fitness) will play a central role. The results will, for the first time, offer a mechanistic (rather then correlative) explanation for broad leaf tree species distribution in Europe and thus, will provide a basis for improved parameterization and evaluation of species distribution models in a climate change context. The new European Research Council (ERC) has granted Prof. Körner one of the extremely rare 5 year 'advanced grants', which contrast any previous granting regime by being personal. The 2 Mio Swiss Francs will permit to explore where, why and how major European tree taxa find climatic range limits. A team of two PhD students and two postdocs plus a technician will be established for a period of four years each (overlapping). The project has various tasks, such as - Idendification of tree species range limits as precise as possible based on GIS and archive data, interviews and site visits - Climatology of those limits based on climate stations and climate data bases - Assess local climate by a large data logging programm with backward cross correlating - Assess marginal versus non marginal location dendrological responses - Assess seedling versus adult positions and viability of seeds - Common garden experiments across climatic gradients (recipical transplants) - Assess freezing resistance of key tissues at key phenophases and link with climatic extremes In a first phase starting 1st April 2009, we will focus on GIS and c