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.
2003
Authors
Bjørn ØklandAbstract
No abstract has been registered
Authors
Knut Rydgren Rune H. Økland Tonje ØklandAbstract
No abstract has been registered
Authors
Lars Sandved Dalen J. Watkinson A.A. Sioson V. Singal D. Kumar N. Ramakrishnan L.S. Heath Carl Gunnar Fossdal R. GreneAbstract
Trees cover over one-third of the world\"s land area and carry out about two-thirds of global photosynthesis. Coniferous forests cover 1.2 billion hectares of Alaska, Canada, Scandinavia, and Russia, and comprise one-fourth of the world\"s boreal and temperate forests. More than 50% of Scandinavia\"s land area consists of forests, mostly coniferous. Information about the molecular responses in trees to biotic and abiotic factors is therefore of great importance - both scientifically and practically.Transcript regulation in response to drought stress was investigated for Norway spruce (Picea abies) with microarrays including 1,700 cDNAs from 5 EST libraries from Pinus taeda and analyzed using the Expresso Microarray Management System.In order to verify the level of drought stress, we measured the physiological status of the plants. After four days of drought, chlorophyll fluorescence was reduced by 6% and after eight days by over 40 %, compared to the control. Hybridizations of spruce RNA to microarray slides was used to probe for changes in transcripts from two to eight days after watering stopped.Monitoring of transcript levels was accomplished by hybridizing spruce cDNA to the 1700 element microarrays. After two days of drought, circa 2 % of the transcripts in Norway spruce were significantly upregulated and 7 % were downregulated. At the end of the experiment after eight days of drought needle chlorophyll fluorescence was reduced by 40 % compared to the control, and 6 % of the transcripts were upregulated and 12 % of the transcripts were downregulated. Results from inductive logic programming are also presented.
Abstract
Farmers in northern Norway have experienced severe winter damage on grassland rather frequently, especially on flat areas and peat soils in regions with an unstable winter climate around zero degrees Celsius. Traditional drainage with drainpipes is normally not sufficient to prevent such damage in these areas. During the past two decades the use of open ditches and surface grading has become the main method of reclaiming and draining peat land. A new heuristic stochastic dynamic analysis method for problems like this, combining simulation and optimisation, is used to explore the profitability of surface grading of peat soils. This analysis indicates that the year in which a ley should be reseeded depends on stage in the growth curve when eventually the winter damage happens as well as on the severity of the damage. Given the present acreage subsidy payment, surface grading is normally profitable from a farmers point of view.
Authors
J. Brian Hardaker Gudbrand LienAbstract
A method of stochastic dominance analysis with respect to a function (SDRF) is described and illustrated. The method, called stochastic efficiency with respect to a function (SERF), partitions a set of risky alternatives in terms of certainty equivalents for a specified range of attitudes to risk. It can be applied for any utility function with risk attitudes defined by corresponding ranges of absolute, relative or partial risk aversion coefficients. SERF involves comparing each alternative with all the other alternatives simultaneously, not pairwise as with conventional SDRF. Hence it yields a subset of the efficient set found by SDRF. Moreover, the method is readily implemented in a simple spreadsheet with no special software needed.
Authors
M. Persson J. Lönnquist Bo Långström Halvor Solheim M. Kyto Anna-Karin Borg-KarlsonAbstract
No abstract has been registered
Abstract
Spatio-temporal analyses of non-epidemic bark beetle populations may provide insight in dynamics predisposing for outbreaks. The present article presents a spatio-temporal analysis of the population dynamics of Ips typographus based on pheromone trap data from southeast and mid-Norway in the post-epidemic period 19792002. The analyses include regression analyses, hierarchical cluster analysis, and analysis of spatial synchrony of beetle time series and climatic data by means of nonparametric spatial covariance functions. The mean abundance of beetles declined linearly with latitude. In addition, the time series means were higher in areas with high forest productivity and rocky soils predisposed to drought. The time series patterns differed significantly between northern and southern study areas. The regional synchrony of the time series was fairly high (0.38), indicating that some large-scale climatic factor may influence the dynamics. Windfelling was the external variable showing the most parallel pattern of correlation to the beetle dynamics. We thus posit that large windfall events may be a major instigator and synchronizer of beetle outbreaks in areas subjected to regionalized weather systems.
Abstract
No abstract has been registered
Authors
Peder GjerdrumAbstract
The timber industry in Norway is quite fragmented. Several small-scale and a few medium-sized sawmill add up to an annual production of 2.5 mill. m3. Since three decades, most of the timber is kiln dried. Modern kilns and enhanced modelling contribute to improved drying quality and increased drying speed. However, due to harsh competition, fast dried, inferior drying quality timber is continually being offered and accepted for trade in the European area. This might put the overall goodwill for timber at hazard in the long run. Unfortunately, the detection of drying quality properties is quite complex. In this situation, industry and RTD-bodies like the Norwegian Forest Research Institute co-operate to offer competence-building activities. Seminars in wood drying and related topics are offered mainly on a corporate basis, thereby introducing an intimate atmosphere for dealing with these cautious topics. A fixed number of participants meet regularly for two day\"s of intensive work over a period of two or three years. The seminars typically include persons from all levels of the factory organisation, incorporating salesmen, mill operators and maintenance together with kiln operators, sometimes also bringing inn external customers. Work alternate between practical experiments, presentations and training. The activity is continued in working groups between the meetings. All seminars are adequately reported with respect to findings, thereby enhancing the business value of the achievements. The seminars also provide an invaluable basis for research projects and for recruiting fresh candidates. For the institute, this symbiosis with industry helps keeping focus on factors influencing profitability in the timber business.
Authors
Steen Koekebakker Gudbrand LienAbstract
No abstract has been registered