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.
2006
Authors
Toril Drabløs EldhusetAbstract
No abstract has been registered
Authors
Toril Drabløs EldhusetAbstract
No abstract has been registered
Abstract
The life-cycle, overwintering stategy and control of Arion lusitanicus in Norway is documented and discussed.
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No abstract has been registered
Abstract
In a balanced experiment based on 20 field plots located in a 21 km(2) Scots pine forest in southeast Norway covering age classes from newly regenerated to old forest, leaf area index (LAI) was determined in field by a LAI-2000 instrument and hemispheric photography. Based on a fortualized framework, i.e., the so-called Beer-Lambert law, gap fraction derived from small-footprint airborne laser scanner data was regressed against field-measured LAI. LAI was strongly (R-2 =0.87-0.93), positively, and linearly related to the log-transformed inverse of the gap fraction derived from the laser scanner data. This was as expected according to the Beer-Lambert law, as was the absence of an intercept, producing a directly proportionality of the two variables. We estimated an extinction coefficient for the first return echoes to be 0.7, fortunately fairly stable across age classes, and this is likely to be a parameter specific for the applied laser scanner system under the given flight and system settings, such as flying altitude and laser pulse repetition frequency. It was demonstrated that airborne laser was able to detect defoliation in terms of estimated changes in LAI, by three repeated laser data acquisitions over the area where severe insect attacks were going on in between the acquisitions. (c) 2006 Elsevier Inc. All rights reserved.
Authors
Alhaji S. Jeng Trond Knapp Haraldsen Per Anker PedersenAbstract
No abstract has been registered
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No abstract has been registered
Abstract
The paper analyses and discusses possible impacts on Norwegian agriculture of an EU membership based on the regionalized agricultural sector model CAPRI. Norwegian agriculture is characterized by a small-scale farming structure and high levels of support. Previous analyses have shown that Norwegian agriculture is expected to undergo dramatic changes because of EU membership in terms of farm income, production and structural change. Our study indicates that a substantial share of the agricultural production can be maintained at the national level. Milk and crop production may remain largely unaffected, while meat production decreases in the range of 10–20% compared to a reference run without membership. However, a reduction in total farm income by about 40% indicates that structural adjustments will follow EU accession. The results are discussed in view of the pattern of adjustments observed in Finland and Austria after EU accession in 1995. The need for the dairy industry to take advantage of the improved market access is stressed. Attention is also called to some strengths and limitations of the CAPRI model to analyse large-scale policy changes and to identify model improvements as an area of future research.
Authors
Juha Kaitera Heikki Nuorteva Jarkko HantulaAbstract
No abstract has been registered
Abstract
When conifers such as Picea abies Karst. (Norway spruce) are attacked by insects or pathogens, they often respond by producing increased quantities of terpenoid oleoresin. This response can be mimicked in young P. abies seedlings by treatment with methyl jasmonate (MJ). In this study, we determined the effects of MJ on terpenoids and other chemical defenses of mature P. abies, and investigated whether this treatment protected trees against attack by the blue-stain fungus Ceratocystis polonica (Siem.) C. Moreau, the most important fungal associate of the spruce bark beetle Ips typo-graphus L. Methyljasmonate treatment induced the formation of traumatic resin ducts in the developing xylem, enhanced resin flow and stimulated increased accumulation of monoterpenes, sesquiterpenes and diterpene resin acids. However, only minor changes were detected in terpene composition in response to MJ treatment and no changes in soluble phenolic concentration were measured. There was much variability in the timing and degree of response to MJ among clones. The observed chemical and anatomical changes in response to MJ treatment were correlated with increased resistance to C. polonica, suggesting that terpenoid oleoresin may function in defense against this pathogen.