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.
2002
Authors
Wim de Vries Gert Jan Reinds H.F. van Dobben D. de Zwart Dan Aamlid P. Neville M. Posch J. Auée J.C.H. Voogd E.M. VelAbstract
No abstract has been registered
Abstract
Several strong westerly storms hit Western Norway during the winter of 1986-87. We studied the uptake, loss and visible effects of sea salt aerosols in Scots pine and Norway spruce. Foliage of was sampled at distances 0-100 km from the coastline between 59¢ª and 65¢ª N, and analysed for chloride, sodium and other elements. The range of chloride and sodium concentrations in needles was 0.5-5.0, and 0.1-3.0 mg g-1, respectively. The local variation was very large close to the coast. The relation to distance from the sea was improved by using distance from the nearest fjord rather than from the outer coastline. Other elements were less variable and not related to distance from the sea, or to sea salt concentrations. Only 1-10% of the needles sea salt content could be removed by 2 minutes washing in distilled water, and still much less of other elements. The amount of sea salt removed by washing was less related to distance from the sea than was the total content. Visible damage to the foliage occurred at chloride concentrations above 1 mg g-1 in the needles. Our conclusions are that analysis of the needles chloride or sodium content is a robust method for confirming damage to tree foliage by sea salt aerosols. Fjords as well as the ocean are significant sources of sea salt aerosols. Large local variation in salt deposition and damage will occur at a rugged coast. Nutrients and other elements are not significantly affected by the sea salt deposition. The use of chloride or sodium as a tracer for dry deposition should take into account not only the enrichment of these elements in canopy throughfall, but also the accumulation in the needles.
Abstract
No abstract has been registered
Abstract
The effect of cold acclimation and defence activators on snow mould resistance and expression of pathogenesis-related (PR-) genes were investigated in winter cereals and perennial ryegrass. Cold acclimation, known to induce snow mould resistance, had apotentiating effect on snow mould-induced PR-gene expression in winter wheat. Chitosan treatment induced chitinase expression and in some cases also snow mould resistance in winter wheat. Bion treatment reduced snow mould resistance in perennial ryegrass.
Abstract
Cleaning of containers to counteract infection that might cause root dieback should remove old, adhering media and roots that may harbour pathogens. This study investigated seedling growth and the number of viable fungal propagules retained on the container cavity walls as a result of different container cleaning treatments: washing with cold water (ca 8C) only, or in addition with a bath temperature of 60, 70, 80 or 95C for 30 seconds.More fungal propagules were isolated from containers washed in cold water, than from the other treatments. The most frequently isolated fungi were Paecilomyces sp. and Penicillium sp., which are well known saprophytes. Bacteria and yeast did not seem to be affected by the washing.Electron microscopy studies of container cavity walls revealed many organic particles and fungal spores on the walls of coldwashed containers. Among other fungal spores there were visible chains of Paecilomyces spp. spores.Containers that were washed at 80C had some organic debris attached to the cavity walls, but no spores were visible. In used and unwashed containers fungal spores, hyphae and organic debris were found on the container cavity walls. Containers in which the major part of the seedlings previously had suffered from root dieback might have contained a considerable amount of inoculum before washing.Almost 60% of the seedlings grown in unwashed containers had dead or very stunted root systems, whereas about 10% of the seedlings in cold washed containers suffered from severe root dieback. Additional warm water treatment further reduced the root dieback of this group of containers. In unwashed containers in which healthy seedlings had been grown, about 4% seedlings and after cold washing no seedlings with root dieback were observed.The cold washing procedure had a positive effect on seedling height, but there was no additional effect of the warm water treatment. We conclude that cold pressurised washing alone does not provide adequate control of root dieback and that an additional warm water bath of at least 60C is recommended.
Authors
Bjørn ØklandAbstract
Several studies conclude that sun-exposed habitats with sufficient supply of dead wood are essential for many saproxylic and mycetophagous beetle species in forests. This has induced Scandinavian foresters to leave artificial tall stumps on clear-cuts in spruce forests.In the present study of Norway spruce forest, habitat preferences during flight were studied for saproxylic and mycetophagous beetles recorded as sporocarp-visitors of Fomitopsis pinicola and Fomes fomentarius, using 690 randomly placed window traps in 69 sites covering three forest types: clear-cuts, young and oldgrowth stands.Many of the sporocarp-visitors showed a strong preference for oldgrowth forest, avoiding clear-cuts and young replantations. By stepwise linear multiple regression, presence of canopy cover appeared as a major factor while variables associated with sporocarps and dead wood were most often secondary in importance. The results indicate that sufficient canopy cover is important for many sporocarp-visiting beetles in Norway spruce forests
Authors
Guro BrodalAbstract
No abstract has been registered
Academic – Quality seed – a factor for sustainable progress
JG Hampton, NM de Carvalho, M Kruse, ...
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
In a greenery trial of Noble fir in western Norway, most branches had good quality until 1994 when 31 % of the branches were discarded. Since then a high level of losses has been noted and 87 % were discarded in 2000. A survey in 1998 revealed that the needle blight fungus Delphinella abietis was the main cause. It seems that frost did not initiate or maintain the disease in the stand, but generally low temperatures may have been important. Discarded branches with the fungus have been left on the ground and have probably been important in maintaining a high level of attack.