API src

Found 187 results.

Establishment of Teak plantations for high-value timber production in Ghana

Background and Objectives: The project area is located in the Ashanti Region of Ghana / West Africa in the transition zone of the moist semideciduous forest and tropical savannah zone. Main land use in this region is subsistence agriculture with large fallow areas. As an alternative land-use, forest plantations are under development by the Ghanaian wood processing company DuPaul Wood Treatment Ltd. Labourers from the surrounding villages are employed as permanent or casual plantation workers. Within three forest plantation projects of approximately 6,000 ha, DuPaul offers an area of 164 ha (referred to as Papasi Plantation) - which is mainly planted with Teak (Tectona grandis) - for research purposes. In return, the company expects consultations to improve the management for sustainable timber and pole production with exotic and native tree species. Results: In a first research approach, the Papasi Plantation was assessed in terms of vegetation classification, timber resources (in qualitative and quantitative terms) and soil and site conditions. A permanent sampling plot system was established to enable long-term monitoring of stand dynamics including observation of stand response to silvicultural treatments. Site conditions are ideally suited for Teak and some stands show exceptionally good growth performances. However, poor weed management and a lack of fire control and silvicultural management led to high mortality and poor growth performance of some stands, resulting in relative low overall growth averages. In a second step, a social baseline study was carried out in the surrounding villages and identified landowner conflicts between some villagers and DuPaul, which could be one reason for the fire damages. However, the study also revealed a general interest for collaboration in agroforestry on DuPaul land on both sides. Thirdly, a silvicultural management concept was elaborated and an improved integration of the rural population into DuPaul's forest plantation projects is already initiated. If landowner conflicts can be solved, the development of forest plantations can contribute significantly to the economic income of rural households while environmental benefits provide long-term opportunities for sustainable development of the region. Funding: GTZ supported PPP-Measure, Foundation

Assessment of genetic diversity of legumes in the highlands of Northern Vietnam for genetic resource conservation and sustainable landuse

Increasing population pressure is leading to unsustainable land use in North Vietnamese highlands and destruction of natural habitats. The resulting loss of biodiversity includes plant genetic resources - both wild (= non-cultivated) species and cultivated landraces - adapted to local conditions, and local knowledge concerning the plants. A particularly important group among endangered plants are the legumes (1) because Southeast Asia is a major centre of genetic diversity for this family, and (2) because the potential contribution of legumes to sustainable land use is, due to their multifunctionality (e.g., soil improvement, human and livestock nutrition), especially high. The project aims to contribute to the conservation and sustainable use of genetic resources of legumes with an integrated approach wherein a series of components are combined: (1) A participatory, indigenous knowledge survey complemented by information from the literature; (2) germplasm collection missions (for ex situ conservation) complemented by field evaluation and seed increase; (3) genetic diversity analysis of selected material by molecular markers; and (4) GIS based analysis of generated data to identify areas of particular genetic diversity as a basis for land area planning and in situ preservation recommendations. Project results are expected to be also applicable to similar highlands in Southeast Asia.

Forschergruppe (FOR) 456 degree of celsius: The role of Biodiversity for element cycling and trophic interactions: An experimental approach in a grassland community

AZV Project West Greenland

The AZV (Altitudinal Zonation of Vegetation) Project was initiated in the year 2002. On the basis of a detailed regional study in continental West Greenland the knowledge about altitudinal vegetation zonation in the Arctic is aimed to be enhanced. The main objectives of the project are: a) considering the regional study: characterize mountain vegetation with regard to flora, vegetation types, vegetation pattern and habitat conditions, investigate the differentiation of these vegetation characteristics along the altitudinal gradient, develop concepts about altitudinal indicator values of species and plant communities, extract suitable characteristics for the distinction and delimitation of vegetation belts, assess altitudinal borderlines of vegetation belts in the study area. b) considering generalizations: test the validity of the altitudinal zonation hypothesis of the Circumpolar Arctic Vegetation Map ( CAVM Team 2003), find important determinants of altitudinal vegetation zonation in the Arctic, develop a first small scale vegetation map of entire continental West Greenland. Field work consists of vegetational surveys according to the Braun-Blanquet approach, transect studies, soil analyses, long-time-measurements of temperature on the soil surface and vegetation mapping in three different altitudinal vegetation belts (up to 1070 m a.s.l.).

Schwerpunktprogramm (SPP) 1158: Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas; Bereich Infrastruktur - Antarktisforschung mit vergleichenden Untersuchungen in arktischen Eisgebieten, The long-term landscape evolution of the Lambert Rift - An integrated thermochronological approach

Das Energiewende-Szenario 2020 - Ausstieg aus der Atomenergie, Einstieg in Klimaschutz und nachhaltige Entwicklung

Natural disease control by root endophytes in a changing climate

The hypothesis that the dark septate root endophyte Phialocephala fortinii provides biological control of Phytophthora diseases to trees is tested under two temperature regimes. Phytophthora spp. are very aggressive plant pathogens affecting also woody plants in the natural environment. Studies on biological control of Phytophthora diseases are scarce, but antagonistic effects of endophytic fungi have been demonstrated in a few cases. In temperate and boreal forests, conifers are much less susceptible to Phytophthora diseases than deciduous broadleaf trees, whereas their roots are very frequently colonized by dark septate endophytes (DSE) with Phialocephala fortinii s.l., a supposedly asexual ascomycete, being the dominant component. This fungus also colonizes hardwoods, but to a lesser degree. Recent population genetic studies showed that P. fortinii s.l. consists of at least 15 reproductively isolated cryptic species (CSP). We hypothesise that P. fortinii s.l. may protect its host from Phytophthora disease depending on CSP and environmental conditions. A model system will be developed and applied to test this hypothesis using Norway spruce (Picea abies), beech (Fagus sylvatica) and Phytophthora citricola. The experimental program will be multidisciplinary in approach and include molecular, mycological, phytopathological (infection experiments, epifluorescence microscopy) and statistical methods.

ERA-NET - Development of test methods for non wood small-scale combustion plants

Non wood fuels for small-scale furnaces have attracted increasing interest in several European countries. New technological approaches are on the way, but the verification of any such developments is difficult and there is a large uncertainty about testing procedures and equipment. While for wood combustion standardized European measuring regulations are available and broadly applied, the testing of cereal fuel combustion is generally not following a commonly accepted procedure. Consequently the results of such measurements are not fully comparable. This applies particularly for the international level, which is here of particular relevance due to the fact that a combustion technology development for a niche application can only be economically viable if a sufficiently large marketing area can be taken into focus. The overall objective of the proposal is therefore to contribute through research to the development of uniform and comparable European procedures for testing of small-scale boilers up to a power out of 300 kW for solid biomass from agriculture like straw pellets and energy grain. The driving forces and barriers will be worked out; existing legal regulation for the installation (approval by the local authorities) in the participating countries will be collected. The state of the art of the non wood biomass boiler technology will be identified; the need for standardized tests for type approval tests and the measures to establish a European Standard will be shown. Measurement methods with special emphasis on efficiency and emissions will be worked out and the requirements and specifications of test fuels will be proposed. Test runs will be carried out following preliminary test procedures based on existing European standards for wood boilers. Based on the results of these test runs a draft for a Europe-wide uniform test procedure will be proposed. Preparatory work for a European standardization process including a round robin test will be done.

Regulation der photosynthetischen Effizienz der Biomassebildung im dynamischen Lichtklima bei exemplarischen Grünalgen und Diatomeen

In dem Vorhaben wird untersucht, wie wirksam die absorbierte Lichtenergie in Biomasse konvertiert wird. Vergleichend werden Grünalgen und Diatomeen unter verschiedenen Licht- und Nährstoffbedingungen studiert. Auf diese Weise können die metabolischen Kosten unter Nährstoffmangel oder anderen produktivitätsbegrenzenden Bedingungen studiert werden. So wird auch die Säureanpassung ausgewählter Phytoplankter untersucht, um die Biomassebildung in extrem sauren Tagebaurestseen auf physiologischer Ebene zu verstehen. Es konnte gezeigt werden, dass unter Stickstoffmangel die Überführung anorganischen Kohlenstoffs in Biomassebildung durch eine Veränderung der makromolekularen Zusammensetzung der Zellen ähnlicher Effizienz stattfindet, wie unter optimaler Stickstoffversorgung. Dies führt zu einer ökologisch bedeutsamen Teilentkopplung des C und N Kreislaufs im Ökosystem. Ähnliches beobachtet man auch bei der Anpassung von Phytoplanktonalgen an extrem saure Bedingungen wie man sie in sauren Tagebaurestseen vorfindet.

Energiemanagement für Supercap-Brennstoffzellenfahrzeuge

Eine Brennstoffzelle als Primärenergiequelle mit einem Doppelschichtkondensator (Supercap) als Zwischenspeicher zu kombinieren ist ein vielversprechender Ansatz für zukünftige Elektrofahrzeuge. In Kooperation mit einem Fahrzeughersteller wurden verschiedene Strategien für ein Energiemanagement für die Kombination einer Brennstoffzelle mit einem Doppelschichtkondensatormodul entworfen und verglichen. Basierend auf der aktuellen Geschwindigkeit und Beschleunigung werden verschiedene Fahrzeugzustände bezüglich kinetischer Energie und Leistungsbedarf unterschieden. In Abhängigkeit von der verfügbaren Leistung von Supercaps und Brennstoffzelle wird eine optimale Leistungsaufteilung zwischen den beiden Energiequellen ermittelt. In Bremsphasen wird durch Rekuperation Energie zurückgewonnen und in den Supercaps gespeichert. Wenn die Supercaps vollgeladen sind oder ihre maximale Ladeleistung erreicht haben, übernehmen mechanische Bremsen die übrige Ladeleistung. Da diese Situation zu einem Energieverlust führt, sollte sie möglichst vermieden werden. Um immer die notwendige Beschleunigungsleistung und gleichzeitig auch ein Maximum an Rekuperation zu garantieren, wird der Ladezustand der Supercaps kontinuierlich und dynamisch an die kinetische Energie des Fahrzeugs angepasst. Verschiedene Strategien wurden in Matlab/Simulink mit einem Stateflow-Chart zur Abbildung der Zustände implementiert. Die verfügbare Supercapleistung wird mit Hilfe eines impedanzbasierten Modells für Supercaps berechnet. Mit diesen Strategiemodellen können die Leistungsfähigkeit der verschiedenen Strategien verglichen und die Einflüsse von Parametern untersucht werden. Ziel eines Energiemanagements ist es, den Wasserstoffverbrauch zu minimieren und die notwendige Leistung zu jeder Zeit sicherzustellen. Bei der Bewertung der Strategien wird der Wasserstoffverbrauch, die verlorene Bremsenergie und eine mögliche Geschwindigkeitsreduzierung verglichen. Mit einer optimalen Strategie können bis zu 23 Prozent Wasserstoff während eines definierten Fahrprofils gespart werden.

1 2 3 4 5 … 17 18 19