@inproceedings{MunkClauderPfriem2019, author = {Munk, Christoph and Clauder, Lothar and Pfriem, Alexander}, title = {Sound absorption coefficient of thermally modified and unmodified wood species measured in an impedance tube}, series = {Northern European Network for Wood Science and Engineering (WSE) - 15th Annual Meeting 2019}, booktitle = {Northern European Network for Wood Science and Engineering (WSE) - 15th Annual Meeting 2019}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2890}, year = {2019}, abstract = {Different parts of the guitar body are made of certain wood species, selected by their specific properties. The sound board, which is mainly made of spruce or cedar, transfers the vibration of the strings to the resonance body by means of the bridge. The sides and the back of the guitar rather reflect the sound of the acoustic vibrations and are predominantly made of tropical hardwoods like palisander, mahogany or ebony species. These species have limited availability and are listed on the CITES Annex I and II. To substitute tropical wood species, thermally modified European wood species with improved acoustic properties and dimensional stability may be used. Although the acoustic reflection of the sides and the back parts of a guitar body is an important property, there is not much knowledge about this reflection behaviour of wood. A few studies like the work of Hong (1989), Kang (2010) or Smardzewski et al. (2013) investigated the sound absorption properties of unmodified wood. Subsequently this study considers the sound absorption coefficients of unmodified and thermally modified European wood species in comparison to an unmodified tropical wood species.}, language = {en} } @article{deMiguelDiezTolosanaEstebanPurfuerstetal.2021, author = {de Miguel-D{\´i}ez, Felipe and Tolosana Esteban, Eduardo and Purf{\"u}rst, Thomas and Cremer, Tobias}, title = {Analysis of the Influence That Parameters Crookedness and Taper Have on Stack Volume by Using a 3D-Simulation Model of Wood Stacks}, series = {Forests}, volume = {12}, journal = {Forests}, number = {2}, publisher = {MDPI}, issn = {1999-4907}, doi = {10.3390/f12020238}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2527}, pages = {10}, year = {2021}, abstract = {The influence that parameters crookedness and taper have on the stack volume was analyzed by using a 3D-simulation model in this study. To do so, log length, diameters at the midpoint and both ends, crookedness, bark thickness, taper and ovality were measured in 1000 logs of Scots pine. From this database, several data sets with different proportions of crooked and tapered logs in stack as well as with different degrees of taper and crookedness were created and taken as basis to simulate the stacks and carry out the analysis. The results show how the variation of these parameters influences the stack volume and provide their volume variation grades. These rates of variation were compared with measurement guidelines of some countries and previous research works. In conclusion, the parameters crookedness and taper influence the stack volume to a considerable extent. Specifically, the stack volume is increased as the crookedness degree or the proportion of crooked logs increases. In contrast, the stack volume is reduced as the taper degree or the proportion of tapered logs increases. Furthermore, the results demonstrate the capability of this simulation model to provide accurate results which can serve as a basis for future studies.}, language = {en} } @article{TakovPilarskaLindeetal.2021, author = {Takov, Danail and Pilarska, Daniela and Linde, Andreas and Barta, Marek}, title = {Infectious and parasitic diseases of phytophagous insect pests in the context of extreme environmental conditions}, series = {Central European Forestry Journal}, volume = {67}, journal = {Central European Forestry Journal}, number = {2}, publisher = {Sciendo}, issn = {2454-0358}, doi = {10.2478/forj-2020-0018}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2541}, pages = {72 -- 84}, year = {2021}, abstract = {The density of phytophagous insect pest populations is related (directly and indirectly) to several groups of factors that can be broadly divided into: abiotic, biotic and anthropogenic. Each extreme in the abiotic environment at a macro-level leads to a series of consecutive extremes in the biotic environment, which eventually results in micro-level responses in the individual organisms. The manifestation of factors acts in aggregate or in a sequence, creating a chain of processes around us. Insects very efficiently use the abundance of nutritional resources, resulting in a tremendous increase in their population density, and triggering control mechanisms through the emergence of parasitic and pathogenic infections (viruses, bacteria, fungi, microsporidia, protozoa and nematodes). The development of entomopathogenic infections in host populations is directly dependent on the characteristics of both the antagonist and the insect. It is associated with the lifestyle and life cycle of the insect, with features encoded in the mechanism of pathogen action, and limited by the pathogen's virulence and pathogenicity.}, language = {en} } @article{GillichMichlerStolteretal.2021, author = {Gillich, Benjamin and Michler, Frank-Uwe and Stolter, Caroline and Rieger, Siegfried}, title = {Differences in social-space-time behaviour of two red deer herds (Cervus elaphus)}, series = {acta ethologica}, volume = {24}, journal = {acta ethologica}, number = {3}, publisher = {Springer Nature}, issn = {0873-9749}, doi = {10.1007/s10211-021-00375-w}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1962}, pages = {185 -- 195}, year = {2021}, abstract = {Social-space-time-behaviour has developed very differently (e.g. a, loner, a herd, a pack) in the animal kingdom and depends on many different factors, like food availability, competition, predator avoidance or disturbances. It is known, that red deer are differently distributed in human disturbed areas compared to areas with less anthropogenic influences. But knowledge about the potential influence of human presence on social associations and interactions is rare, albeit differences may result in changing impacts on the environment, such as habitat utilization and feeding damage. Therefore, we investigated differences in the space use and social association of red deer. We studied two radio-collared herds of non-migratory populations in two study areas, which were comparable in landscape structure and vegetation structure, but differed in accessibility for visitors and the extent of their presence. Between the two study sites we compared the home range size, the differences in the extent of home range overlap within each study site and the space-time association (Jacobs Index) of individuals. Additionally, we present data on seasonal variations of home range sizes and social association all year round. In order to compare human activity in the study sites, we used the data from our long-term camera trap monitoring. The herd in the area with more human activity had significantly smaller home ranges and had greater year-round social associations in almost all seasons, except summer. We assume that smaller home ranges and higher association between animals may result in a higher feeding pressure on plants and a patchier utilization in areas with higher disturbances.}, language = {en} } @article{SchmelzleBrunsBeckmannetal.2021, author = {Schmelzle, Sebastian and Bruns, Stefan and Beckmann, Felix and Moosmann, Julian and Lautner, Silke}, title = {Using In Situ Synchrotron-Radiation-Based Microtomography to Investigate 3D Structure-Dependent Material Properties of Tension Wood}, series = {Advanced Engineering Materials}, volume = {23}, journal = {Advanced Engineering Materials}, number = {11}, publisher = {Wiley}, issn = {1438-1656}, doi = {10.1002/adem.202100235}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1925}, pages = {1 -- 11}, year = {2021}, abstract = {Synchrotron-radiation-based microtomography enables the 3D analysis of biological samples in situ beyond simple visualization, providing accurate measurements and recording of temporal data. The microtomography end station at P05 (PETRA III, Hamburg, Germany), operated by the Helmholtz Zentrum Hereon, can accommodate complex sample environments such as a load frame for mechanical testing. Herein, the strain analysis of a volumetric time series dataset of small hardwood samples is presented. For this in situ mechanical testing, the load frame is operated in tensile mode, and the biogenic material samples are subdivided into those specialized for tensile forces and those of regular anatomical structure. Digital volume correlation analysis allows for the prediction of strain development at any position in the sample. The tissue specialized for tensile strength can align dislocations formed under tension such that the deformation is stronger and more ordered. The results show how high-resolution imaging of sequential loading and the subsequent localization of strain can reveal functional morphological relationships. These methods can be extended to other biological materials and may prove to be extremely relevant for the analyses of fibrous and/or layered composite materials.}, language = {en} } @article{WinklerHaaseSchwarzetal.2021, author = {Winkler, Christoph and Haase, Stefan and Schwarz, Ulrich and Jahreis, Markus}, title = {Piezoresistive bond lines for timber construction monitoring—experimental scale-up}, series = {Wood Science and Technology}, volume = {55}, journal = {Wood Science and Technology}, number = {4}, publisher = {Springer Nature}, issn = {0043-7719}, doi = {10.1007/s00226-021-01305-6}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1959}, pages = {1379 -- 1400}, year = {2021}, abstract = {Several laboratory studies and experiments have demonstrated the usability of polymer films filled with electrically conductive filler as piezoresistive material. Applied to adhesives, the glue lines of wood products can achieve multifunctional—thus bonding and piezoresistive/strain sensing—properties. Based on critical load areas in timber constructions, upscaled test setups for simplified load situations were designed, especially with regard to a stress-free electrical contact. In a second step, another upscaling was done to small glulam beams. Based on an experimental test sequence, the piezoresistive reactions as well as the behaviour until failure were analysed. The results show in all cases that a piezoresistive reaction of the multifunctionally bonded specimens was measurable, giving a difference in the extent of relative change. Additionally, measured phenomena like inverse piezoresistive reactions, electrical resistance drift and the absence of a piezoresistive reaction were discussed, based on additional strain analysis by digital image correlation. A model of macroscopic and microscopic strains influencing the piezoresistive reaction of the electrically conductive bond line in wood was used to explain all experimental results. Finally, a first scale-up of piezoresistive bond lines from laboratory samples to glulam beams was possible and successful.}, language = {en} } @article{SchaeferJagerSchwarzetal.2021, author = {Sch{\"a}fer, Jesco and Jager, Christopher and Schwarz, Ulrich and Winkler, Christoph}, title = {Improving the usability of piezoresistive bond lines in wood by using impedance measurements}, series = {Wood Science and Technology}, volume = {55}, journal = {Wood Science and Technology}, number = {4}, publisher = {Springer Nature}, issn = {0043-7719}, doi = {10.1007/s00226-021-01311-8}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1942}, pages = {937 -- 954}, year = {2021}, abstract = {Various studies on wood adhesives filled with conductive fillers for future application to structural monitoring showed a piezoresistive (resistance change with strain) response of the adhesive bond lines that is measurable under direct current. The results also showed a relatively high signal noise with low sensitivity. Using impedance spectroscopy as a measurement technique, the improvements in frequency-dependent piezoresistivity over DC (Direct Current) resistography of multifunctional bonded wood were studied. Beech specimens were bonded by one-component polyurethane prepolymer (1C-PUR) filled with carbon black and tested under shear load. The quality of the piezoresistive properties was described by calculating the signal-to-noise ratio (SNR) of the measured signal. A setup-specific frequency band with optimized SNR between 100 kHz and 1 MHz could be derived from the measurements. Several frequencies showed a signal with higher quality resulting in a higher SNR. Regardless of the variations in impedance spectra for all specimens, this frequency band provided several frequencies with improved signal quality. These frequencies give a more reliable signal with lower noise compared to the signal from DC resistography.}, language = {en} } @techreport{HebertLucasDroganLucasetal.2021, type = {Working Paper}, author = {Hebert, Saskia and Lucas-Drogan, Diana and Lucas, Eike and Schneider, Tatjana and Strauß, Anke}, title = {W{\"u}nschenswerte Wohnzuk{\"u}nfte: Herausforderungen, Chancen und Potentiale zur Erh{\"o}hung der strukturellen Resilienz in Elbe Valley}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2150}, pages = {1 -- 93}, year = {2021}, language = {de} } @article{AschenbrandMichler2021, author = {Aschenbrand, Erik and Michler, Thomas}, title = {Why Do UNESCO Biosphere Reserves Get Less Recognition than National Parks? A Landscape Research Perspective on Protected Area Narratives in Germany}, series = {Sustainability}, journal = {Sustainability}, publisher = {MDPI}, issn = {2071-1050}, doi = {10.3390/su132413647}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2166}, pages = {18}, year = {2021}, abstract = {This paper explores how landscape research can contribute to our understanding of why integrated protected area concepts like biosphere reserves get less recognition than national parks. In this regard, we analysed policy documents and online communication of biosphere reserves and national parks, conducted qualitative interviews with conservation professionals and volunteers as well as participant observation in order to identify and compare narratives that guide the communication and perception of both protected area categories. The results show how national parks offer a clear interpretation of space by building on landscape stereotypes and creating landscape legibility and experience-ability through touristification. National Parks also experience conflicts about proper management and combine a variety of goals, often including regional development. Nevertheless, their narrative is unambiguous and powerful. Biosphere reserves, on the other hand, have an image problem that is essentially due to the difficulty of communicating their objectives. They confront the difficult task of creating a vision that combines development and conservation while integrating contrarious landscape stereotypes. We argue for a fundamental engagement with protected area narratives, as this improves understanding of protected areas' transformative potential.}, language = {en} } @article{RederMundAlbertetal.2021, author = {Reder, Stefan and Mund, Jan-Peter and Albert, Nicole and Waßermann, Lilli and Miranda, Luis}, title = {Detection of Windthrown Tree Stems on UAV-Orthomosaics Using U-Net Convolutional Networks}, series = {Remote Sensing}, volume = {14}, journal = {Remote Sensing}, number = {1}, publisher = {MDPI}, issn = {2072-4292}, doi = {10.3390/rs14010075}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2213}, pages = {25}, year = {2021}, abstract = {The increasing number of severe storm events is threatening European forests. Besides the primary damages directly caused by storms, there are secondary damages such as bark beetle outbreaks and tertiary damages due to negative effects on the market. These subsequent damages can be minimized if a detailed overview of the affected area and the amount of damaged wood can be obtained quickly and included in the planning of clearance measures. The present work utilizes UAV-orthophotos and an adaptation of the U-Net architecture for the semantic segmentation and localization of windthrown stems. The network was pre-trained with generic datasets, randomly combining stems and background samples in a copy-paste augmentation, and afterwards trained with a specific dataset of a particular windthrow. The models pre-trained with generic datasets containing 10, 50 and 100 augmentations per annotated windthrown stems achieved F1-scores of 73.9\% (S1Mod10), 74.3\% (S1Mod50) and 75.6\% (S1Mod100), outperforming the baseline model (F1-score 72.6\%), which was not pre-trained. These results emphasize the applicability of the method to correctly identify windthrown trees and suggest the collection of training samples from other tree species and windthrow areas to improve the ability to generalize. Further enhancements of the network architecture are considered to improve the classification performance and to minimize the calculative costs.}, language = {en} }