API src

Found 54 results.

Gene flow and sex ratio of Populus euphratica Oliv. floodplain forests at the Tarim River, Xinjiang, NW China

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.

Water use characteristics of bamboo (South China)

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.

Clustered Subsampling of Double Sampling for Stratification and Growth Model Based Updates of Past Forest Inventories

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.

Can the resistance and resilience of trees to drought be increased through thinning to adapt forests to climate change?

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.

Fragmentation and lack of legitimacy of the international and European forest regime complex in legal perspective

The project will assess the fragmentation, which exists in the international forest regime complex and the resulting lack of legitimation. On this basis, it will explore options to advance coherence and legitimation for an international forest policy and means of its legitimation and legalization. As will be analysed in detail, it appears, that the international forest regime complex suffers from fragmentation in two ways. Firstly, forest issues did probably lag behind in the development of the contemporary international system of environmental law as they lacked the legitimation by a dedicated international agreement, which so many other issues such as biodiversity, climate change and desertification do enjoy. Secondly, due to this and other developments of the international legal system, particular aspects of forest policies are intensively dealt with separately and - arguably - without much coordination by diverse international regimes like, for instance, the FCCC, the CBD and the ITTA. To the more, relevant measures for such forest policy, like, for instance, certification, compulsory labelling schemes and related trade restrictions are nowadays subject to rules and standards of the WTO and thus need to be carefully designed in order to prevent any inconsistencies. In order to complement this global assessment, the legal frame of forest policy within the European Union will be analysed, which also suffers from a lack of legitimation, but apparently nonetheless developed a number of activities.

Human influences on forests in southern Ethiopia: the case of Shashemane-Munessa-forest

Especially during the last decades, the natural forests of Ethiopia have been heavily disturbed by human activities. Some forests have been totally cleared and converted into fields for agricultural use, other suffered from different influences, such as heavy grazing and selective logging. The ongoing research in the Shashemane-Munessa-study area (Gu 406/8-1,2) showed clearly that, in spite of interdiction and control, forests continue to be cleared and degraded. However, it is not yet sufficiently known, how and why these processes are still going on. Growing population pressure and economic constraints for the people living in and around the forests contribute to the actual situation but allow no final answers to the complex situation. Concerning a sustainable management of the forests there is to no solid basis for recommendations from the socioeconomic and socio-cultural view. Therefore, a comprehensive analysis of the traditional needs and forms of forest use, including all forest products, is necessary. The objective of this project is, to achieve this basis by carrying out intensive field observations, the consultation of aerial photographs, satellite imagery and above all semi-structured interviews with the population in the study area in order to contribute to the recommendations for a sustainable use of the Munessa Shasemane forests.

Poplar communication with its environment

Terpenes (=isoprenoids) are volatile organic compounds (VOCs) emitted by plants but their ecological functions are not fully understood. Poplars are strong isoprene emitters. In preceding studies we have constructed non-isoprene emitting poplars and started with their characterization. We have also constructed poplars expressing pinene synthase. We aim to study the role of isoprene and monoterpenes in herbivore and mycorrhizal interactions. In addition to wild type poplar plants (isoprene and non-monoterpene emitters) we will make use of transgenic poplar lines, that are either non-isoprene emitters or non-isoprene, but constitutive monoterpene emitters. The influence of the VOC emission on the interaction with herbivores and/or ectomycorrhizal fungi will be studied under laboratory, green house and open air conditions. Furthermore, it will be investigated how attack by herbivores affects the survival of ectomycorrhizal fungi or pathogenic fungi and vice versa, and how EM changes the VOC blend emitted by the plants and the performance of leaf feeding insects. Responses of the plant and the ectomycorrhiza will be studied on a molecular level. The results of these studies will provide important knowledge about poplar interaction and defense from herbivory.

Fragmentation of information procurement from large area forest inventory and the link to the policy-making process within the international forest regime complex

This project aims at analysing the contribution of scientific information to the fragmentation of the international forest regime complex (IFRC) by applying an interdisciplinary approach at the interface between forest inventory research and policy science. Its objectives are1. Analyzing the use of inventory information within the IFRC by different national and international bureaucracies and their non-state allies and its effect on fragmentation. 2. Assessing the extent and quality of the inventory information used in policy processes as compared to the potentially available information. 3. Analyzing implemented inventory practices against the scientific state of the art approaches and their role in the context of fragmentation 4. Identifying avenues for scientific knowledge to enter into the IFRC by testing the knowledge-transfer-by-allies-hypothesis. The project will review the technical scientific possibilities of forest inventories and develop a method for assessing quantity and quality of inventory-based information used within the IFRC by national and international bureaucracies. Subsequently, the quality of information used will be assessed against the state of the art in inventory research. Based on the hypothesis that information may only enter the policy process in alliance with powerful actors, who in turn selected the information, the project will analyse the interest-driven selection of information by political actors.

Interaktionen zwischen Buche und Fichte in Abhängigkeit von Trockenheit

In den Wäldern Mitteleuropas dominieren Fichte (Picea abies (L.) Karst.) und Buche (Fagus sylvatica L.). Aufgrund ihrer vorteilhaften Wirkungen und Leistungen werden diese Arten in Mischkulturen bevorzugt, allerdings ist das Verhalten solcher Mischungen bei Stress, unter anderem bedingt durch Klimaveränderungen, infrage gestellt. Anhand eines ökologischen Transektes von feuchten zu trockenen Standorten und eines Überdachungsexperimentes werden die Auswirkungen von Trockenheiten von 3 Teilprojekten untersucht: (A) Zuwachs auf Baum- und Bestandesebene, (B) artspezifische Reaktionsmuster unter inner- und zwischenartlichen Wuchsbedingungen bei trockenheitsbedingter Xylem-Dysfunktion und Kohlenstoffverarmung und (C) Wirkung von Ektomykorrhizen auf Wurzel- und Baumwachstum. Die entlang eines Niederschlagsgradienten erzielten Wechselwirkungen zwischen Fichte und Buche werden untermauert durch experimentelle Befunde und Modellszenarien mit ökophysiologischen Prozessmodellen. Am Projekt sind drei antragstellende Arbeitsgruppen beteiligt sowie zwei externe Arbeitsgruppen. Durch Zusammenführung von Expertise in der langfristigen Versuchsbeobachtung, einzigartiger Infrastruktur, die durch das Kranprojekt im Kranzberger Forst gegeben ist und innovative Modellierungsansätze entsteht ein Projekt mit großer Synergie, Innovation und Erfolgsaussicht.

Agroforstliche Möglichkeiten zur Förderung von Wiederaufforstung in Panama

Die fortschreitende Entwaldung in den Tropen erfordert die Erforschung von Landnutzungskonzepten, welche die Entwaldung reduzieren, die Wiederherstellung von Waldflächen fördern und gleichzeitig die Sicherung des Lebensunterhaltes für die Bevölkerung gewährleisten. Aufforstungen mit schnell wachsenden Wertholzarten können einen solchen Ansatz darstellen. Das größte Hindernis für deren Umsetzung stellt jedoch der lange Zeitraum bis zur Erwirtschaftung erster Rückflüsse dar. Ziel des vorliegenden Projektes ist es, mit Hilfe der Einbringung landwirtschaftlicher Nutzpflanzen in Holzplantagen einen früheren Cash-flow zu ermöglichen und somit Aufforstungen finanziell attraktiver zu gestalten. Zur Überprüfung dieses agroforstlichen Ansatzes sollen beispielhaft für tropische Gebiete Versuchspflanzungen in Panama angelegt werden. Das Versuchsdesign ermöglicht den Vergleich unterschiedlicher Wertholz- Feldfrucht-Kombinationen sowie die Untersuchung der Interaktionen zwischen den beteiligten Arten in Abhängigkeit von verschiedenen Steuergrößen, wie z.B. dem Pflanzabstand. Ziel ist eine Bewertung der ökologischen und sozioökonomischen Eignung der untersuchten Systeme als nachhaltiges Landnutzungskonzept.

1 2 3 4 5 6