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.
2000
Abstract
Aluminium (Al) has been considered to be a central element for risk evaluation of forest damage due to acidification. It has been hypothesised that Al reduces root growth, nutrient uptake and forest vitality. However, forest monitoring studies fail to show correlations between soil acidification and forest health. In general, no direct relation between Al concentration and forest health has been established. Here, Al concentrations in soil solution were manipulated by weekly additions of dilute AlCl3 to levels that are believed to be unfavorable for plant growth. Four treatments (in triplicate) including a reference and three Al addition levels were established. Effects of enhanced Al concentrations on fine root growth, nutrient uptake and crown condition in a mature Norway spruce forest in Norway were tested (1996-1999). After three years of manipulation, crown condition, tree growth and fine root growth were not affected by potentially toxic Al concentrations. However, the Mg content in current year\"s needles decreased at the highest Al addition treatment. The Mg/Al ratio of fine roots of the same treatment had declined too, which suggests that Al blocked Mg uptake at the root surface. The manipulation will be continued for two more years.
Authors
Bjørn ØklandAbstract
Insect species in 20 families of Diptera were collected by an equal number of interception traps in spruce forests of different management practice:young regrowth 5-10 years after logging and replantingmanaged old-growth forestgap opening of old-growth forest with plenty of even-aged dead wooda shady remnant biotope of uncultivated old-growth forest with plenty of dead wood in various levels of decay. Forest cultivation seems to favour saprophagous generalists on behalf of the specialised fungal fauna. The species in mycorrhizal fungi were clearly reduced in young regrowth, while species in wood-inhabiting fungi were most diverse in the remnant biotope with a heterogeneous composition of dead wood.The abundance of saprophagous generalists was significantly increased in the managed forest variants (young regrowth and managed old-growth forest). More studies are necessary to evaluate how the shift in decomposer fauna influence nutrient cycling and other ecosystem processes in forests.
Authors
Dan Aamlid Natalya Vassilieva Per Arild Aarrestad Michael L. Gytarsky S. Lindmo Rodion Karaban Vladimir Korotkov Tord K. Rindal V. Kuzmicheva Kåre Olav VennAbstract
Six sites for forest ecosystem monitoring were established to perform a long-term study of effects of air pollution on pine forest ecosystems along a pollution gradient in the border areas between Norway and Russia. The main pollution source is a nickel smelter.Several methods and analyses were used to investigate different compartments of this northern boreal forest ecosystem. The differences in ecological condition and diversity observed among the research sites are probably due to the air pollution load in the area. The elevated concentrations of Ni and Cu detected in plant tissues, the reduced lichen vegetation on stems and on the forest floor, and the reduced or absent moss vegetation are the most obvious impacts in the investigated area.
Authors
V.R. Nsolomo Halvor Solheim Kåre Olav VennAbstract
No abstract has been registered
Authors
Erik Christiansen Alan A. Berryman Vincent R. Franceschi Trygve Krekling Paal Krokene Nina Elisabeth Nagy Halvor SolheimAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Measurement data on air, precipitation and canopy throughfall chemistry from a network of sites have been combined to study scavenging and deposition processes, with particular emphasis on the oxidised nitrogen species.High deposition rates of oxidised nitrogen occur in coastal areas of SW Norway. These are partly caused by high precipitation rates, partly also because a large fraction of the oxidised nitrogen is present as nitrate in large particles, which are rapidly removed by both wet and dry deposition processes.High wind speeds near the coast result in high concentrations of sea-salt particles in the air and high deposition rates of both nitrate and sea-salt particles, particularly in coniferous forest stands. HNO3 contributes on average only about 10-20% to the sum of aerosol nitrate and HNO3 (sNO(3)). Still, the combined dry deposition velocity of sNO(3) to these forest stands may be between 4 and 6 cm s(-1) on average.
Authors
Jenny Fäldt Halvor Solheim Bo Långström Anna-Karin Borg-KarlsonAbstract
No abstract has been registered
Abstract
The anatomical response of Norway spruce bark polyphenolic parenchyma cells (PP cells) to inoculation with the phytopathogenic fungus Ceratocystis polonica and attack by its bark-beetle vector Ips typographus was examined.Fungal inoculation on the periderm surface had no effect, while inoculation just below the periderm or halfway into the phloem (mid-phloem) generated detectable responses within 3 wk. The responses included increase in PP cell size and in periodic acid - Schiffs staining of PP cell phenolics, wound periderm initiation from PP cells, and cambial zone traumatic resin duct formation. Fungi were not seen in samples 3 wk after subperiderm or mid-phloem inoculation, but were found in some samples 6 and 9 wk after mid-phloem inoculation.In contrast, inoculations into the cambium resulted in partial (3 wk) or complete (6 and 9 wk) fungal colonization and death of tissue in the infected area. This indicates that PP cells have defenses capable of inhibiting fungal growth. Samples taken near bark-beetle galleries had similar anatomical responses as inoculated samples, validating the inoculation approach to studying defense responses in spruce.These results show that PP cells represent not only a constitutive defense system, but are also involved in local and remote inducible defenses against fungal and beetle attack.
Abstract
No abstract has been registered