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Gottschalk T.,Rottenburg College of Forest Sciences | Kover L.,Debrecen University
Vogelwarte | Year: 2016

In 2014,7.2 % of Germany's territory was used for the cultivation of maize. Several studies have shown that maize fields are of minor importance for breeding bird species. The value of maize fields as a habitat for birds has rarely been investigated during summer and autumn. Mist-net data were obtained using 15 nets in a maize field near Gießen, Germany during 44 days between July and October 2012. The aim of the study was to identify (a) the number of bird species and individuals resting in a maize field, (b) the time and duration of their stay and (c) vertical and spatial distribution of bird species during the post-breeding season. In total, 1,019 birds out of 35 species were trapped. The most frequently caught birds were Blue Tit (Cyanistes caeruleus), Tree Sparrow (Passer montanus) and Reed Warbler (Acrocephalus scirpaceus). The number of all caught birds showed significant differences between mist net positions and within vertical height. The distance between field edges and mist nets had no effect on capture rates of birds with the exception of the Chiffchaff (Phylloscopus collybita). Numbers of caught Chiffchaffs decreased with increasing distances to the field edge. Individuals of 14 species have been recaptured after a median of six days, which might imply that they used the maize field for a longer time. Capture rates remained almost constant until August and, caused by an increase of migratory birds, increased continuously by the beginning of October. Although capture rates in maize were lower compared to reed beds and different wooded areas, the number of birds caught implies that a high number of bird species find sufficient resources in maize during summer and autumn. Further investigations are needed to identify the importance of maize as a habitat for birds, especially in comparison to other arable crops or fallow. © DO-G, IfV, MPG 2016. Source

Bioenergy is the main pillar of renewable energies in Germany. This applies equally at European and global level. Biomass use for energy production is intended to substitute fossil energy, is motivated by climate change mitigation objectives, receives significant governmental promotion and exhibits impressive technological dynamics. However, the increasing demand and the low energy density per volume results in the use of large areas and is associated with considerable negative environmental impacts such as intensification and land-use change. Sustainable bioenergy use needs clearly defined standards for environmental, conservation and social objectives. First moves towards benchmarking such standards are defined by the European Union's Renewable Energy Directive (RED) but are only valid for liquid biomass so far. They should be amended and augmented for solid biomass as well. Source

Hein S.,Rottenburg College of Forest Sciences | Ehring A.,Forstliche Versuchs und Forschungsanstalt Baden Wurttemberg | Kohnle U.,Forstliche Versuchs und Forschungsanstalt Baden Wurttemberg
Allgemeine Forst- und Jagdzeitung | Year: 2014

Historically, the sweet chestnut tree [Castanea sativa Mill.] has been known as a tree species that is rich in biomass production and frequently used in coppice forests. The following investigation was conducted to explore the possibility of producing valuable timber from this species. The basis were measurements on 42 temporary plots with sweet chestnut plots in southwestern Germany (Rhineland-Palatinate, Baden-Wuerttemberg) and eastern France (Alsace) as well as six long-term experiment plots in Baden-Wuerttemberg (Fig. 1, Table 1). We measured crown diameter, height of crown base, tree height, diameter at breast height (N=409 trees) and assessed age, height and diameter growth dynamics from stem analyses of selected trees. The results show that the production of valuable timber the needs to take into account the specific growth pattern of sweet chestnut: Height growth and the associated ability to expand crowns decreases strongly from a rather young age of approx. 25 years (Fig. 2). Sweet chestnut proves rapidly self-pruning, particularly in young development stages (< 25 years). As a consequence, artificial pruning is usually not obligatory for the production of valuable timber. However, in mixed stand a combined pruning of dead and living branches may be appropriate. Production of target diameters of 60 cm at breast height (valuable timber) or diameters up to 40 cm (e.g. small diameter round wood, timber for palisades) are possible in relatively short production periods; however, intensive thinning is needed: the diameter growth decreases quickly with increasing age. At higher ages, the potential for promoting diameter growth is rather limited even through very strong thinnings (Fig. 5). Intensive thinning as early as possible is also necessary with respect to reduce the risk of timber devaluation through the chestnut blight caused by the fungus Cryphonectria parasitica as well as ring shake. A silvicultural concept for the production of valuable timber (target diameter of 60 cm) accomodating the species-specific growth dynamics of sweet chestnut will require spacing to allow adequate extension of the crowns at rather early stages (dominant height of approx. 12 m) in order to exploite fully the site-specific diameter growth potential. Working with consequently released and more or less equally spaced ca. 60-80 crop trees per hectare, knot-free valuable timber can be produced in periods of about 60 years. Source

Metzner J.,Deutscher Verband fur Landschaftspflege DVL e.V | Jedicke E.,Goethe University Frankfurt | Luick R.,Rottenburg College of Forest Sciences | Reisinger E.,Thuringer Landesanstalt fur Umwelt und Geologie TLUG | Tischew S.,Anhalt University of Applied Sciences
Naturschutz und Landschaftsplanung | Year: 2010

The near-natural pasturing of our cultural landscape stands for a modern, multi-functional agriculture. Many farms with grazing animals have an important share in effectively implementing the European challenges to protect biological diversity, climate and water. The subsequent paper - supported by numerous associations - makes proposals for a better establishment of extensive grazing in the funding guidelines of the Common Agricultural Policy (CAP) of the EU after 2013. Existing instruments are to be advanced in the following areas: On extensively grazed grasslands it should in future be possible to generally activate payment claims of the 1 st column, and to combine them with aid programmes of the 2nd column. In order to reduce the risks of reclaims for the applicants the sites are to be identified by a specific code with an "integrated administration and control system", and the implementation of the measures is to be controlled according to nature conservation criteria. In the context of the 2 nd column the study recommends the expansion of agri-environmental measures - including better co-financing by the EU, additional incentives and contract periods of up to 20 years. Additionally landscape management programmes have to be established on the basis of the Regulation of the EAFRD (Art. 57) - including invested-related measures which are not covered by agri-environmental schemes. The comprehensive counselling of the farms aims to promote a better integration of extensive grazing, ensuring the optimal combination of measures of the 1 st and 2 nd column. The study recommends the following measures which are particularly eligible: (a) extensive all-year continuous grazing with cattle and horses, (b) conversion of arable fields into extensively grazed grasslands in flood areas and on fen soils, and (c) biotope management with sheep and goats. Source

Thorn S.,Sachgebiet Forschung und Dokumentation | Bassler C.,Sachgebiet Forschung und Dokumentation | Gottschalk T.,Rottenburg College of Forest Sciences | Hothorn T.,University of Zurich | And 4 more authors.
PLoS ONE | Year: 2014

Windstorms, bark beetle outbreaks and fires are important natural disturbances in coniferous forests worldwide. Windthrown trees promote biodiversity and restoration within production forests, but also cause large economic losses due to bark beetle infestation and accelerated fungal decomposition. Such damaged trees are often removed by salvage logging, which leads to decreased biodiversity and thus increasingly evokes discussions between economists and ecologists about appropriate strategies. To reveal the reasons behind species loss after salvage logging, we used a functional approach based on four habitat-related ecological traits and focused on saproxylic beetles. We predicted that salvage logging would decrease functional diversity (measured as effect sizes of mean pairwise distances using null models) as well as mean values of beetle body size, wood diameter niche and canopy cover niche, but would increase decay stage niche. As expected, salvage logging caused a decrease in species richness, but led to an increase in functional diversity by altering the species composition from habitat-filtered assemblages toward random assemblages. Even though salvage logging removes tree trunks, the most negative effects were found for small and heliophilous species and for species specialized on wood of small diameter. Our results suggested that salvage logging disrupts the natural assembly process on windthrown trees and that negative ecological impacts are caused more by microclimate alteration of the dead-wood objects than by loss of resource amount. These insights underline the power of functional approaches to detect ecosystem responses to anthropogenic disturbance and form a basis for management decisions in conservation. To mitigate negative effects on saproxylic beetle diversity after windthrows, we recommend preserving single windthrown trees or at least their tops with exposed branches during salvage logging. Such an extension of the green-tree retention approach to windthrown trees will preserve natural succession and associated communities of disturbed spruce forests. © 2014 Thorn et al. Source

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