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.
2005
Authors
Peder GjerdrumAbstract
Heart- and sapwood demonstrates different wood quality features which should be taken into account when deciding how to make use of each single trunk. To analyse heartwood relations, radial cores were sampled from ten trunks and one thousand trees in four gymnosperm species from the European Alps, covering a wide variety of growth conditions. The objective was to test whether the simple and straightforward model denoted the heartwood age rule (HAR) would give an adequate description of the observed heartwood - age relations in these species. In this paper, preliminary results are reported, confirming the validity of HAR: For each of the species, the number of heartwood rings equals the square root of the cambial age less a constant parameter, to the second power. The parameter evaluated to (valid cambial age rang in brackets): 3.31 (up to 220 years) for Scots pine; 1.28 (up to 270 years) for larch; 1.47 (up to 490 years) for stone pine; and 1.10 (up to 110 years) for yew. The explained part of the variance in the square root transformed observations of heartwood rings was 90-99%. For the examined specimens, HAR applied to observations at breast height as well as along single trunks from base to top, irrespective within or beneath the living crown. The findings confirm former reports and enhance the application of HAR to a wider geographic area and to new species. The results should suitably be incorporated in wood quality models.
Abstract
No abstract has been registered
Authors
Mekjell MelandAbstract
No abstract has been registered
Abstract
In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance even during winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by a subsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according to present guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40-60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved. In 1991, the first subsurface flow constructed wetland for treatment of domestic wastewater was built in Norway. Today, this method is rapidly becoming a popular method for wastewater treatment in rural Norway. This is due to excellent performance evenduring winter and low maintenance. The systems can be constructed regardless of site conditions. The Norwegian concept for small constructed wetlands is based on the use of a septic tank followed by an aerobic vertical down-flow biofilter succeeded by asubsurface horizontal-flow constructed wetland. The aerobic biofilter, prior to the subsurface flow stage, is essential to remove BOD and achieve nitrification in a climate where the plants are dormant during the cold season. When designed according topresent guidelines a consistent P-removal of > 90% can be expected for 15 years using natural iron or calcium rich sand or a new manufactured lightweight aggregate with P-sorption capacities, which exceeds most natural media. When the media is saturated with P it can be used as soil conditioner and P-fertilizer. Nitrogen removal in the range of 40–60% is achieved. Removal of indicator bacteria is high and < 1000 thermotolerant coliforms/100 ml is normally achieved.
Abstract
No abstract has been registered
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No abstract has been registered
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No abstract has been registered
Authors
Anders Baudin Lars Eliasson Åsa Gustafsson Lina Hagström Klara Helstad Anders Qvale Nyrud Jon Bingen Sande Erlend Y. Haartveit Rune ZiethénAbstract
No abstract has been registered
Authors
Dag Ekeberg Camilla B. Eriksen Hans Ragnar NorliAbstract
A method was created for quantitative and qualitative analyses of different PBDE´s in various matrixes. A mixture of PBDE congeners was used to make calibration curves, and acetone and cyclohexane was used as solvents for the extraction. Analyses were performed using a GC-MS sector instrument. The method was tested on sediments from the Netherlands. Recovery tests were carried out on soil from Kroer in Ås.
Abstract
No abstract has been registered