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
Arne Sandnes Halvor SolheimAbstract
Tree resistance to the patogenic blue stain fungus Ceratocystis polonica was studied in a monoclonal stand of Norway spruce (Picea abies [L] Karst.) in relation to tree social status and diameter at breast height (DBH). The DBH distribution of the 33-year-old stand ranged from 5 to 35 cm. There were clear differences in tree height between the suppressed (DBH 7.4-10.3 cm), co-dominant (DBH 11.8-17.4 cm) and dominant (DBH 18.6-23.9 cm) tree classes. The resistance was tested by mass inoculating trees with a low (400 inoculations m-2, 60 cm inoculation belt) or high (400 inoculations m-2, 120 cm inoculation belt) dosage. The small, suppressed trees were more susceptible to inoculation than the co-dominant and dominant trees, based on amount of blue-stained and occluded sapwood, lesion length, and dead cambium/phloem. A threshold in tree social status or tree size might be important in the overall resistance to fungal infection.
Authors
John Durrus Linnell Erlend Birkeland Nilsen Unni Støbet Lande Ivar Herfindal John Odden Ketil Skogen Reidar Andersen Urs BreitenmoserAbstract
No abstract has been registered
2001
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Rune Halvorsen Økland Tonje Økland Knut RydgrenAbstract
No abstract has been registered
Authors
David L. Jones Toril Drabløs Eldhuset Helen Agnes de Wit Berit SwensenAbstract
No abstract has been registered
Authors
David L. Jones Toril Drabløs Eldhuset Heleen A. de Wit Berit SwensenAbstract
While the release of organic acids from plants may offer a protection against rhizotoxic Al, the efficiency of this mechanism will be reduced by the rhizosphere microbial community
Authors
Toril Drabløs Eldhuset Berit Swensen Heleen A. de Wit Nina Davidsen Gro WollebækAbstract
No abstract has been registered
Authors
Heleen A. de Wit Jan Mulder Per Holm Nygaard Dan Aamlid Magne Huse Egil Kortnes Gro Wollebæk Roald BreanAbstract
Aluminium (Al) is a key element in critical load calculations for forest. Here, we argue for re-evaluating the importance of Al. Effects of two levels of enhanced Al concentrations and lowered Ca:Al ratios in the soil solution in a field manipulation experiment in a mature spruce stand (1996-1999) on tree vitality parameters were tested. In addition, Al solubility controls were tested. Various loads of Al were added to forest plots by means of an irrigation system. Potentially toxic Al concentrations and critical ratios of Ca to inorganic Al were established.The ratio of Ca to total Al was not a suitable indicator for unfavourable conditions for plant growth. No significant effects on crown condition, tree growth and fine root production were observed after three years of treatment. In 1999, foliar Mg content in the highest Al addition treatment had declined significantly. This agreed with the known response to Al stress of seedlings in nutrient solution experiments. No support was found for using the chemical criterion Ca:Al ratio in soil solution, foliar and root tissue as an indicator for forest damage due to acidification. Al solubility was considerably lower than implied by the assumption of equilibrium with gibbsite, particularly in the root zone.The gibbsite equilibrium is commonly used in critical load models. Substitution of the gibbsite equilibrium with an Al-organic matter complexation model to describe Al solubility in soil water may have large consequences for calculation of critical loads. The results indicate that critical load maps for forests should be reconsidered.
Authors
Petter NilsenAbstract
No abstract has been registered