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
Authors
Oddvar SkreAbstract
Forsøk viser at mørkerespirasjonen i veksande skot av norsk gran (Picea abies (L.)Karst.) har samanheng med den daglege veksten. Liknande samanhengar er funne i bladskiver av bjørk (Betula pubescens Ehrh.) og alm (Ulmus glabra var. scabra Huds.). Årleg akkumulert respirasjon viser korrelasjon med utbreiingsgrensene til desse treslaga. Det er venta at klimaendringa på langt sikt vil føra til at tregrensene for dei undersøkte treslaga vil stiga med 400 m. Forsøk med bjørk viser at dette treslaget har eit stort potensial for temperaturtilpassing ved ulike kompensasjonsmekanismar.
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.
Abstract
Relationships between crown density and growth of Norway spruce stands are presented, after removal of the effects of major natural influences. On 569 monitoring plots comprising 40 000 trees, crown density has been annually assessed during 1991 to 1996.Stand growth was determined from measurements of diameter and height in 1991 and in 1996. Various models explaining mean crown density and annual growth of the stands as a function of natural factors, like age and site index, were compared.The influence of the natural factors were then removed by recalculating crown density to residual values from one preferred model, and by recalculating growth to relative values given in percent of model predictions.Crown density and its residuals were positively correlated to growth. These relationships were weak in terms of their ability to explain variation (low R2). However, the various relationships consistently indicated that roughly 1% change in crown density corresponded to 1% change in growth. This relationship also included common spatial variation over Norway: a large part of southeast Norway had unexplained low crown density and unexplained low growth.Some other, smaller regional consistencies were found as well. The study supports the use of crown density assessments, and further it encourages the use of growth data in the search for major stress factors responsible for present forest condition.
Authors
Jenny Fäldt Halvor Solheim Bo Långström Anna-Karin Borg-KarlsonAbstract
No abstract has been registered
Authors
O. Janne Kjønaas Harald Aalde Lars Sandved Dalen Heleen A. de Wit Toril Drabløs Eldhuset Bernt-Håvard ØyenAbstract
Between 1990 and 2010 the projected emissions of greenhouse gases in Norway is assumed to increase 24%. As a signatory to the Kyoto Protocol, Norway is supposed to limit the greenhouse gas emissions in the period 2008-2012 to 1% above the 1990 level.Potentially, forestry activities may contribute as a means to achieve the set target of emission reductions. The initial Norwegian views and proposals for definitions and accounting framework for activities under Articles 3.3 and 3.4 of the Kyoto Protocol was reported to the UNFCCC August 1 2000 by the Norwegian Ministry of Environment.There was also an annex to the submission with preliminary data and information on Articles 3.3 and 3.4 of the Kyoto Protocol. This paper is based on this annex, and focuses mainly on data for forests and other woodlands. Preliminary data indicate that approximately 85% of the carbon (C) pool of forested systems is found in the soil.The major part of the annual C sequestration takes place in living biomass and soil, while sequestration in wood products and landfills etc. has been found to be of minor importance. It must be noted that the reported data are preliminary and contain large uncertainties.
Authors
A. Sæbø Øystein JohnsenAbstract
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.
Authors
Juha SiitonenAbstract
No abstract has been registered
Authors
Heleen A. de WitAbstract
No abstract has been registered
Abstract
No abstract has been registered