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.
2005
Forfattere
Tor Håkon SivertsenSammendrag
Arguments for developing explicit ways of clarifying the scope of scientific methods are the content of the first paragraph. Then several concepts like phenomenon, parameter and model are defined and discussed. The well known general scientific method, the hypothetico-deductive principle is then discussed and given a more restrictive interpretation than usual, and the outcome of this discussion is a proposal of a documentation system of meteorological parameters, either measured parameters or parameters derived by model calculation. The concept of quality of meteorological data is then defined. The main lines of a system for automatic control of hourly data from an automated station network are shortly discussed. An example of the use of the proposed documentation system is presented, and in the last paragraph of the report some explicit recommendations for sets of meta-data connected to exchange of meteorological data between institutions are presented.
Forfattere
Tor Håkon SivertsenSammendrag
An interpretation of the general scientific method, the hypothetico-deductive principle, is first presented and discussed. It is containing a slightly more restrictive interpretation than usual (The test of a system is interpreted not as a testing merely of scientific hypotheses in a mathematical shape, but as an explicit testing of the definition of the quantitative parameters and the measuring systems of these parameters as well). The outcome of this discussion is a proposal of a documentation system of quantitative meteorological and biological parameters, either measured parameters or parameters derived by model calculation. The documentation system presented is currently being implemented in a web-based system for administration of meteorological parameters at The Norwegian Crop Research Institute. An example of using this documentation system in a biological context, connected to a simple pest warning model for potato late blight is presented. The significance of discussing the scope of such methods concludes the paper.
Forfattere
Heleen A. de Wit Jan Mulder Toril EldhusetSammendrag
Det er ikke registrert sammendrag
Forfattere
Heleen A. de Wit Jan Mulder Toril EldhusetSammendrag
Det er ikke registrert sammendrag
Forfattere
Skartveit, John Pommeresche, Reidun Langhelle, G Byrkjedal, I Solhøy, Torstein Reidun PommerescheSammendrag
We collected shrews using pitfall traps in a forest area in Kvam, Hordaland, Western Norway in 1997-98. Altogether, 205 individuals of pygmy shrew, Sorex minutus and 129 individuals of common shrew, Sorex araneus were collected. Both shrew species occurred over a wide range of forest types. Common shrew was absent in bogs and pygmy shrew apparently was absent in alder forest. Common shrew was relatively evenly distributed among forest types while the catches of pygmy shrew was significantly lower in deciduo
Forfattere
May-Guri Saethre Trond HofsvangSammendrag
Timed catches of Cydia pomonella (L.) males in sex pheromone traps were used to investigate the influence of twilight and climatic parameters on the flight activity of the moths at different latitudes. Traps were operated from 15 May until 31 July at several locations between 59ºN and 60ºN in south-eastern Norway, and at Sogndal (61ºN) in western Norway, during 1997-2000. Time and duration of twilights were calculated from May-August for each trap-location, and compared with the activity of C. pomonella. Flight response appeared to be determined by the daily photoperiod, corresponding to time of sunset at the different latitudes involved in the study. This response began about two hours before sunset, and declined around 23:00 and 24:00 hours in the evening, in western and eastern Norway, respectively. Main flight activity in both eastern and western Norway was recorded when temperatures were in the range 10-20 ºC, the relative humidity was above 50 %, and at wind speeds below three m/s at the time of capture. In Norway, light conditions are suitable for C. pomonella flight activity all night long during the entire lifetime of the adult moths. It is concluded that temperature is the limiting factor for flight at high latitudes.
Forfattere
Tor J. JohansenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Skogforsk har utviklet en svært følsom metode for å påvise skadelige sopper i trær og trevirke. Dette kan bli viktig i kampen mot rotkjuke, som koster skognæringen i Europa 6-7 milliarder kroner årlig, og mot andre skadelige sopper.
Forfattere
Anders LunnanSammendrag
Forest owners get only a nominal pay when delievering forest residues for energy purposes. At the same time there might be negative environmental effects as nutrient loss and production loss. Compensation measures could be ash disposal and fertilization. This has a cost, but due to sustainability restrictions compensation measures might be seen as obligatory. Other negative environmental effects include possible effects on biodiversity and acidification. Positive effects include impact on GHG balance and reduced silvicultural costs. We study this problem from the forest owner?s view and from the society?s view in a cost-benefit context. The results vary with physical inputs as deposition and soil type and with assumptions concerning economic variables as shadow price of carbon.
Sammendrag
At least three mechanisms are known to cause synchrony among spatially separated insect populations: 1) dispersal among populations, 2) synchronous stochastic effects, often referred to as the Moran effect, and 3) trophic interactions with other species that are either themselves synchronized or mobile.The present study brings in the role of insect taxa for spatial synchrony. The spatial synchrony observed in several North American and Eurasian epidemic bark beetles was compared with patterns of synchrony in outbreaks of defoliating forest Lepidoptera, revealing a marked difference between these two major insect taxa.The bark beetles exhibited a generally lower degree of spatial synchrony than the Lepidoptera, possibly because bark beetles are synchronized by different weather variables that are acting on a smaller scale than those affecting the Lepidoptera, or because inherent differences in their dynamics leads to more cyclic oscillations and hence more synchronous spatial dynamics in the Lepidoptera. Among the epidemic bark beetles tested, spatial synchrony of outbreaks in the Eurasian spruce bark beetle Ips typographus was significantly higher than for the other species.