Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2011
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Ishita Ahuja Birgit Hafeld Borgen Magnor Kåre Hansen Bjørn Ivar Honne Caroline Müller Jens Rohloff John Trevor Rossiter Atle M. BonesAbstract
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Authors
Markus Reichstein Miguel D. Mahecha Nuño Carvalhais Gitta Lasslop Sonia I. Seneviratne Holger Lange Alessandro Cescatti Mirco MigliavaccaAbstract
The release of carbon dioxide (CO2) from the land surface via different respiratory processes is a major flux in the global carbon cycle, antipodal to CO2 uptake via photosynthesis. Understanding the sensitivity of respiratory processes to temperature is central for quantifying the climate–carbon cycle feedback. In a recent study we approximated the sensitivity of terrestrial ecosystem respiration to air temperature (Q10) across 60 FLUXNET sites. For this objective, we developed a novel methodology that circumvents seasonally confounding effects. Contrary to previous findings, our results suggest that Q10 is independent of mean annual temperature, does not differ among biomes, and is confined to values around 1.4 ± 0.1. However, the shape of the strong relation between photosynthesis and respiration is highly variable among sites. The results may partly explain a less pronounced climate–carbon cycle feedback than suggested by current carbon cycle climate models. In the talk we put our findings into context with other recent results and critically discuss their potential for evaluating temperature sensitivity of respiration in terrestrial biosphere models and parameterizing future land surface schemes.
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Wood protection in the last century has mainly been based on chemical treatments. Additionally, the type of construction of wooden buildings and the choice of wood species play an important role. Degradation of wood is not only caused by fungi or bacteria but also by insects. Termites have been a potential risk to wooden structures not only in the warmer regions of our continents but also beyond the regions of their natural habitat due to transport of wood. A new treatment, Electro osmotic pulsing technology (PLEOT), has been tested in lab termite tests and fungi tests. The two choice and non-choice termite tests were carried out using different duration of exposure and different initial wood moisture content. The results show growth of mould fungi on untreated wood samples with high initial wood moisture content after 4 weeks of termite testing whereas PLEOT treatment strongly reduced the development of moulds. Termite mortality was high on untreated wood samples with high initial moisture content but not on wood samples with low initial moisture content. This is explained by mould growth on the wetter samples, which termites don\"t tolerate in large amounts. The loss of wood mass due to termite attack could be reduced by using PLEOT. The mortality of termites was higher in test systems with protected wood samples than untreated samples. PLEOT could be used successfully against fungal attack. The treatment reduced on the one hand mould growth in a termite test and on the other hand reduced strongly the attack of brown rot fungi in a lab test.
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Biodiversity is assumed to have high value for many people, but the necessary preservation also incurs a cost for the forest owner. Typically, studies of this cost are at the stand level, and hence, not very accurate as the cost may vary even within the stand. In this work, we use a 1m×1m grid, generated from LIDAR data, to estimate the cost for harvesting and forwarding. The method could be utilized to calculate compensation, and to select between key woodland habitats to minimise the cost. In three of four test cases, the main cost was reduced harvested volume, but in one case the key woodland habitat also made the harvesting operations more expensive.
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Celine ReboursAbstract
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The aim of this study is to see if the raw material influences fixation and leachability of wood preservatives. Moving towards more eco-friendly and –concious society, the wood industries must adjust itself to new rules and regulations. Greener solutions in wood protection are being tested and introduced, older systems are being improved, but questions still arise concerning some elements currently used in wood preservation. Preservatives leaching into the nature is a problem, especially agents that consist copper. Studies have been conducted on the raw material`s influence on impregnability and variations in sapwood penetration have been found. This gives reason to believe that the leaching of wood preservatives is also influenced by the raw material. This study tries to set the variation of leachability of Wolmanit CX-8 and Tanalith into a system, evaluating the origin of a tree and the origin of a sample. The study uses Scots pine (Pinus sylvestris) as a raw material. Material was harvested from different stands in Norway and Denmark. Pine`s sapwood was cut into samples in size of 20x20x50mm. The samples were treated with the wood protection agents Wolmanit CX-8 and Tanalith. The variation in leachability within trees, between trees and between different stands was studied. Within this material, it is possible to trace the individual sample to its original position in the stem. Samples were climatized, impregnated with preservatives and leached according to standard EN84. Copper and boron content in water samples was determined by an ICP (Inductively Coupled Plasma) technique. Comparing leaching results with different variables, correlation was found with latitude and vertical position of the sample, indicating that southern stands leach out more preservative. The lowest part of the tree does not fixate preservatives.