Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2013
Forfattere
Helle Margrete Meltzer Per Brandtzæg Helle Katrine Knutsen Beate Fossum Løland Jon Øyvind Odland Janneche Utne Skåre Liv Elin Torheim Heidi Amlund Augustine Arukwe Aksel Bernhoft Anne Lise Brantsæter Jutta Dierkes Merete Åse Eggesbø Gunnar Sundstøl Eriksen Wenche Frølich Livar Frøyland Christiane Kruse Fæste Ragnhild Halvorsen Margaretha Haugen Gro Ingunn Hemre Per Ole Iversen Åshild Krogdahl Jørgen Fredrik Lassen Rolf Lindemann Jan Ludvig Lyche Mohammad Azam Mansoor Audun Helge Nerland Bjørn Næss Anders Ruus Bjørn Steen Skålhegg Inger-Lise Steffensen Leif Sundheim Line Emilie Sverdrup Cathrine Thomsen Olav Østerås Jan AlexanderSammendrag
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Forfattere
Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Unni Abrahamsen Jafar Razzaghian Vinh Hong Le Hugh Riley Einar Strand Børge Holen Elisa Gauslaa Tove Kristina Sundgren Mauritz Åssveen Berit Nordskog Hege Særvold Steen Guro BrodalSammendrag
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Forfattere
Karl ThunesSammendrag
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Forfattere
Rajko Vidrih Alena Gibalova M Korosec E Zlatic Janez Hribar Eivind VangdalSammendrag
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Sammendrag
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Sammendrag
The ground-based harvesting system consisting of a harvester and a forwarder is the dominant harvesting system in parts of the world, due to its high productivity. Both machines usually operate along extraction trails, and are equipped with cranes that can reach some distance from the extraction trail. In this work we optimize the layout of an extraction trail network by considering how terrain topography influences the cost of forwarding. Given the complexity of finding optimal machine trails for terrain transportation, traditional optimization methods might be limited due to the problem size. In this study, the optimization is done with a greedy constructive heuristic and a Greedy Randomized Adaptive Search Procedure (GRASP) metaheuristic, and the results of the two solution techniques are compared. Both the greedy heuristic and the GRASP metaheuristic were examined for a semi-random terrain and a smooth cone-shaped terrain, and provided useable extraction trail layouts in terms of how a forest machine operates on slopes. The objective value of the solution found by the GRASP metaheuristic was 5.6% better than the greedy heuristic in the semi-random terrain, and 2.3% better in the cone-shaped terrain. The result of this study showed that the GRASP metaheuristic is useful for finding feasible routes in the terrain, increasing efficiency. The method could be useful for planning feasible routes in the terrain, thereby increasing efficiency, or for acquiring a better estimate of the cost of terrain transport in price setting.
Forfattere
Heleen de Wit Anders Bryn Annika Hofgaard Jonas Karstensen Maria Malene Kvalevåg Glen Philip PetersSammendrag
Expanding high elevation and high latitude forest has contrasting climate feedbacks through carbon sequestration (cooling) and reduced surface reflectance (warming), which are yet poorly quantified. Here, we present an empirically-based projection of mountain birch forest expansion in south-central Norway under climate change and absence of land use. Climate effects of carbon sequestration and albedo change are compared using four emission metrics. Forest expansion was modeled for a projected 2.6 °C increase of summer temperature in 2100, with associated reduced snow cover. We find that the current (year 2000) forest line of the region is circa 100 m lower than its climatic potential due to land use history. In the future scenarios, forest cover increased from 12 to 27% between 2000 and 2100, resulting in a 59% increase in biomass carbon storage and an albedo change from 0.46 to 0.30. Forest expansion in 2100 was behind its climatic potential, forest migration rates being the primary limiting factor. In 2100, the warming caused by lower albedo from expanding forest was 10 to 17 times stronger than the cooling effect from carbon sequestration for all emission metrics considered. Reduced snow cover further exacerbated the net warming feedback. The warming effect is considerably stronger than previously reported for boreal forest cover, because of the typically low biomass density in mountain forests and the large changes in albedo of snow-covered tundra areas. The positive climate feedback of high latitude and high elevation expanding mountain forests with seasonal snow cover exceeds those of afforestation at lower elevation, and calls for further attention of both modelers and empiricists. The inclusion and upscaling of these climate feedbacks from mountain forests into global models is warranted to assess the potential global impacts.
Sammendrag
In Norway, water quality of small streams draining agricultural catchments has been monitored since 1993 by the Agricultural and Environmental Monitoring Program. This article attempted to examine the concentration levels, temporal dynamics and long-term trends (1993–2009 and 1996–2009) of Al, Fe, Cu, Mn and Zn in streams draining the catchment areas of Skuterud (4.5 km2) and Mørdre (6.8 km2), located in south-east Norway. In the Mørdre stream, Al, Fe, Cu, Mn and Zn all showed statistically significant downward trends (p<0.05), whilst in the Skuterud stream only Al and Fe showed statistically downward significance (p<0.05). The general declining trends of metal concentrations are most likely associated with reduction of acid rain deposition in southern Norway. In spite of this declining trends, over the 14–17 years of monitoring mean monthly concentrations of total Al (2.0–3.2 mg L−1), Fe (1.3–2.5 mg L−1) and Cu (8.9–26.1 µg L−1) in Skuterud and Mørdre streams, respectively exceeded the limits of the Norwegian Water Framework Directives, whereas the concentrations of Mn (22.3–40.8 µg L−1) and Zn (13.1–99.4 µg L−1) fell within the range of desired limits. Of the total water samples analysed from Skuterud (n=370) and Mørdre streams (n=255), nearly 80–84%, 70–87% and 79–96% were above the desired limits for Al (0.2 mg L−1), Fe (0.3 mg L−1) and Cu (3 µg L−1), respectively. In 2011, water analysis from drainage of forest soils (in Skuterud catchment) measured total Al: 0.42–0.79 mg L−1 and total Fe: 0.84–1.0 mg L−1 which were two to three folds greater than the desired limits. In general, weak correlations between runoff and concentrations of the metals in the streams were noted. Future research should focus on identifying the sources of Al, Fe and Cu and management interventions of elevated metal inputs to Skuterud and Mørdre streams.
Forfattere
Marit Jørgensen Kirsten Tørresen Marit Dyrhaug Ingrid Myrstad Jan Svendsen Tone Magnussen Anniken Førde A. DiTommasoSammendrag
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