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.
2010
Forfattere
Christer MagnussonSammendrag
The spread of the pinewood nematode (PWN) Bursaphelenchus xylophilus in Europe is a threat to 36 million ha Nordic coniferous forests. In spite of a strict phytosanitary regulation of wood imports, the volumes and an unclear distribution of PWN could result in an introduction into the Nordic region. In the present climate expression of pine wilt disease is expected only in hot summers. Hence, the detection of PWN in the Nordic area is likely to remain unnoticed for a considerable period of time. In Fennoscandia more than 9000 samples have been analyzed from risk areas and risk commodities. The focus often has been on the breeding substrate of the vector insects in the genus Monochamus. A recent study on a simulated introduction in Norway (Økland et al in print) indicates that 14 years may elapse before detection by the present level of 400 samples annually. It was demonstrated that an earlier detection of PWN provided by an annual sample volume of 10 000 samples would still not be sufficient for successful eradication of PWN by 3 km radius clear-cuts. So, large sampling volumes and strict import regulations for PWN are highly important for the Nordic area. Økland, B.O. Skarpaas, M. Schroeder, C. Magnusson, Å. Lindelöw & K. Thunes 2010. Is Eradication of the Pinewood Nematode (Bursaphelenchus xylophilus) Likely? An Evaluation of Current Contingency Plans. Risk Analysis in print Key Words: Pinewood nematode, Nordic area, sampling, eradication, regulation
Forfattere
Klaus MittenzweiSammendrag
Det er ikke registrert sammendrag
Forfattere
Marcel Van Oijen Ad Schapendonk Mats HøglindSammendrag
Background and Aims The carbon balance of vegetation is dominated by the two large fluxes of photosynthesis (P) and respiration (R). Mechanistic models have attempted to simulate the two fluxes separately, each with their own set of internal and external controls. This has led to model predictions where environmental change causes R to exceed P, with consequent dieback of vegetation. However, empirical evidence suggests that the R : P ratio is constrained to a narrow range of about 0·4-0·5. Physiological explanations for the narrow range are not conclusive. The aim of this work is to introduce a novel perspective by theoretical study of the quantitative relationship between the four carbon fluxes of P, R, growth and storage (or its inverse, remobilization). Methods Starting from the law of conservation of mass - in this case carbon - equations are derived for the relative magnitudes of all carbon fluxes, which depend on only two parameters: the R : P ratio and the relative rate of storage of carbon in remobilizable reserves. The equations are used to explain observed flux ratios and to analyse incomplete data sets of carbon fluxes. Key Results The storage rate is shown to be a freely varying parameter, whereas R : P is narrowly constrained. This explains the constancy of the ratio reported in the literature. With the information thus gained, a data set of R and P in grassland was analysed, and flux estimates could be derived for the periods after cuts in which plant growth is dominated by remobilization before photosynthesis takes over. Conclusions It is concluded that the relative magnitudes of photosynthesis, respiration, growth and substrate storage are indeed tightly constrained, but because of mass conservation rather than for physiological reasons. This facilitates analysis of incomplete data sets. Mechanistic models, as the embodiment of physiological mechanisms, need to show consistency with the constraints.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Andreas TreuSammendrag
Wood modification with furfuryl alcohol is an extensively investigated process and already produced commercially. Furfurylated wood is in the focus of a European project on its use for the production of high performance windows. Different wood species were treated with furfuryl alcohol and tested on water uptake, dimensional changes, leaching in water, resistance to fungal degradation, and ecotoxicity. The results show a reduced water uptake and a reduced swelling of the furfurylated wood samples. A high resistance against fungal attack of the treated wood samples can be shown. A low amount of furfuryl alcohol was leached out and the water samples of two different leaching tests showed in general low toxicity. Southern yellow pine showed good results in all of the tests and has potential for the production of window frames according to the tests performed.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Kristin DaugstadSammendrag
Det er ikke registrert sammendrag
Forfattere
Trond Rafoss Knut Sælid Arild Sletten Lars Fredrik Gyland Liv EngravsliaSammendrag
The threat posed by invasive alien species to global crop production and biodiversity is recognized as one of the major drivers of global change today. Here we report on a successful implementation and operational use of new technology to support risk- and crisis management in the case of fighting an invasive plant disease. The open geospatial standards Web Feature Service Transaction (WFS-T) was implemented in software for GPS-enabled mobile phones communicating with a GeoServer backend in order to track down and eradicate disease outbreaks and susceptible host plants. This new technology offering georeferenced events online from field provides new possibilities for real time action in risk and crisis management.
Forfattere
Gilbert Kamgan Nkuekam Halvor Solheim Z. Wilhelm De Beer Joha W. Grobbelaar Karin Jacobs Michael J. Wingfield Jolanda RouxSammendrag
Ophiostoma spp. include important pathogens of trees and causal agents of sapstain. These fungi infect wounds on trees and are typically carried by insects, especially bark beetles. Ophiostoma spp. on coniferous hosts in the Northern Hemisphere are well-known. However, other than for the serious pathogens O. ulmi and O. novo-ulmi, very little research has been done on the occurrence of this group of fungi on native broad-leaved trees, especially in the Nordic countries. In this study, surveys were conducted in several areas of Norway to isolate Ophiostoma spp. associated with wounds on native broad-leaved trees belonging to the genera Betula, Fagus, Quercus, Sorbus and Tilia. Morphological studies and comparisons of DNA sequences for the ITS, 5.8S and part of the beta-tubulin gene regions were used to confirm the identity of the fungi collected. Ophiostoma spp., and especially their Pesotum anamorphs, were common on wounds on the trees sampled. In most cases, they were associated with wood stain. Ophiostoma spp. collected included predominantly O. quercus, O. borealis sp. nov., and O. denticiliatum. The results of this study emphasize that the diversity of Ophiostoma spp. on broad-leaved trees is still incompletely understood in Norway and other European countries.
Forfattere
Kirsty McKinnonSammendrag
Det er ikke registrert sammendrag