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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.

2016

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Abstract

Sheep grazing is an important part of agriculture in the North Atlantic region, defined here as the Faroe Islands, Greenland, Iceland, Norway and Scotland. This process has played a key role in shaping the landscape and biodiversity of the region, sometimes with major environmental consequences, and has also been instrumental in the development of its rural economy and culture. In this review, we present results of the first interdisciplinary study taking a long-term perspective on sheep management, resource economy and the ecological impacts of sheep grazing, showing that sustainability boundaries are most likely to be exceeded in fragile environments where financial support is linked to the number of sheep produced. The sustainability of sheep grazing can be enhanced by a management regime that promotes grazing densities appropriate to the site and supported by area-based subsidy systems, thus minimizing environmental degradation, encouraging biodiversity and preserving the integrity of ecosystem processes.

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Abstract

Effects of clear-cut harvesting on ground vegetation plant species diversity and their cover are investigated at two Norway spruce sites in southern Norway, differing in climate and topography. Experimental plots at these two sites were either harvested conventionally (stem-only harvesting) or whole trees including crowns, twigs and branches were removed (whole-tree harvesting), leaving residue piles on the ground for some months. We compare the number of plant species in different groups and their cover sums before and after harvesting, and between the different treatments, using non-parametric statistical tests. An overall loss of ground vegetation biodiversity is induced by harvesting and there is a shift in cover of dominant species, with negative effects for bryophytes and dwarf shrubs and an increase of graminoid cover. Differences between the two harvesting methods at both sites were mainly due to the residue piles assembled during whole-tree harvesting and the physical damage made during the harvesting of residues in these piles. The presence of the residue piles had a clear negative impact on both species numbers and cover. Pile residue harvesting on unfrozen and snow-free soil caused more damage to the forest floor in the steep terrain at the western site compared to the eastern site.

Abstract

Characterization of biomass ash melting and thermal behavior is crucial to prevent and reduce ash related problems in biomass-fired boilers, In present work, ash melting behaviours of spruce saw dust and bark were investigated by simultaneous thermal analysis (STA), The decomposition stages of sawdust and bark biomass were characterized by four peaks, respectively, The four peaks are the first relatively small one at temperatures about 317-341 °C, a second large peak at 419-451 °C, a small third peak at 860-1000 °C and a small endothermic peak at 1290-1400 °C, DSC curves of bark sample at both heating rates were shifted towards lower temperatures than DSC curves of sawdust fuels, On average, the degradation process starts 5 °C earlier and the second exothermic peaks in both heating rates are found even 20 °C earlier, The remaining residue of bark samples was approximately two times higher than that of sawdust, The ignition temperatures of both spruce and pine bark were slightly shifted to higher temperatures compared to those of spruce and pine sawdust samples, STA experiments of exanimated biomass fuels indicated that their critical melting temperatures lie in the range of 860-1000 °C, The information obtained in this study qualifies the STA method as a suitable and rather simple method for the determination of ash melting and thermal behavior of woody biomass. © 2016 ETA-Florence Renewable Energies.