Das Projekt "Ecological Effects of Energy Nurse Crops - Forest Restoration and Biomass Production" wird/wurde gefördert durch: Stiftung Energieforschung Baden-Württemberg. Es wird/wurde ausgeführt durch: Universität Freiburg, Waldbau-Institut.Storms, droughts, and pest insect outbreaks regularily disturb forests, in particular those that are characterized by tree species that are not in accordance with site conditions. Ordinary restoration methods establishing juvenile target trees in open areas often face problems in terms of seedling survival owing to stress from frost, drought, sun, or pests. From an ecological point of view, delayed restoration success can result in increased nutrient elution and reduction of carbon stored in soils. To address this problem nurse crops comprising robust and fast growing tree species such as birch (Betula ssp.) or poplar (Populus ssp.) have been used to establish an overstory sheltering sensitive target tree species against weather extremes. This project aims to utilize forest biomass provided by nurse crops to support the production of renewable energy (Energy Nurse Crops, ENCs). However, exporting additional forest biomass affects the nutrient cycles and thus may undermine the principle of sustainability. Therefore, this project will investigate and evaluate the concept of ENCs and its consequences relative to ordinary restoration methods especially for forest ecosystems sensitve to windblow such as pure black spruce stands (Picea abies) stocking on periodically wet soils. Tree species such as birch or poplar are known to develop extensive root systems. Because ENCs reliably establish in open areas and because their roots can quickly penetrate soils, they may be able to retain much more nutrients on site than any target tree species could ever do when established under unfavourable growth conditions. Eventually the positive effects of nutrient retention and soil carbon fixation may outweigh the negative effects of nutrient export with biomass. To explore this question, field experiments quantifying nutrient elution, nutrient pools, carbon pools, biomass production, and root growth will be conducted in ENC stands of different age, site, and tree species. Introducing additional tree species such as birch or poplar may also affect forest ground vegetation composition and species abundance. A research approach addressing species diversity of forest ground vegetation will be considered in the future.
Das Projekt "WLS Report 35: Determination of natural space risk in the catchment areas of the Kreisbach and Schwemmbach, hydrologic analysis and rainfall simulation" wird/wurde gefördert durch: Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft Österreich. Es wird/wurde ausgeführt durch: Universität für Bodenkultur Wien, Institut für Alpine Naturgefahren.The sites that were to become experimental areas were selected by coworkers of the Special Research Project Forest Ecosystem Restoration (SRP), as they allowed for a comparison of pairs of pure spruce stands and natural mixed stands. The selection of such sites was limited to the northern Alpine piedmont at the altidude between 400 and 800 metres above sea level. The experimental site Kreisbach in Lower Austria (municipality of Wilhelmsburg, district Lilienfeld) as well as the experimental site Schwemmbach in Upper Austria (municiplaity of St. Johann am Walde, district Braunau am Inn) were selected to become the areas of investigation. It is the aim of this study to evaluate the effects of forest ecosystem restoration on the discharge of floods. It could be stated that ideal discharge conditions prevail on all forest stands examined. There could not be found any significant difference between the different stand types. In part, this may be well explained by the high site quality classes on the examined grounds. The pure spruce stands lacked high raw humus horizons, which are responsible for the hydrophobe behavior. Despite contrary notes in the literature (AULITZKY 1989) on the flysch sites extremely low surface runoff coiffizients were determined. This may be due to the fact that the damming layers lie too deep to cause the emergence of strong surface discharge in the forests.