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.
1987
Authors
Kristian Bjor Magne HuseAbstract
No abstract has been registered
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Anders Göransson Toril Drabløs EldhusetAbstract
No abstract has been registered
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Finn Roll-HansenAbstract
No abstract has been registered
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Bjørn Langerud Martin SandvikAbstract
Effects of growth medium physical conditions were studied. Peat and two series of peat mixed with hydrophobic mineral wool or perlite in three mixing ratios were prepared. Growth media porosities were characterized by the standardized time method and seedling development by measurements of stem length and fresh and dry weight.Seedlings grown in media containing mineral wool showed less mortality, were larger and had more living root apices than seedlings in media lacking mineral wool. Growth media influenced most the stem length and dry weights and was best at higher porosity. The difference between mineral wool and perlite amendments was greater for dry weight than stem length, although the effect of mixing ratio was observed for mineral wool only.The media induced qualitative differences in shoots (foliage spiralling) and roots (branching, number of living root apices, lenticel intumescence).
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No abstract has been registered
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Jon Dietrichson Halvor SolheimAbstract
No abstract has been registered
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K. Frimpong-MensahAbstract
No abstract has been registered
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Romanus C. Ishengoma Ludvik NagodaAbstract
No abstract has been registered
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Erik Christiansen Richard H. Waring Alan A. BerrymanAbstract
Bark beetles are among the few native insects that can kill large numbers of trees in a single year. The present paper reviews recent work on the relationship between conifer resistance to bark beetle attack and tree vigor, e.g. in terms of wood production per unit of foliage. Experimental studies in the Pacific Northwest and the southeast U.S.A., and in Norway, are drawn upon to show that tree resistance to attack may be closely related to the amount of current and stored photosynthate that is available for defense. An experimental approach is advocated to critically test the relationship between host-tree resistance and the limitations on the transfer of critical resources to the site of attack.
Authors
Øystein Austarå Arnstein Orlund Asbjørn Svendsrud Arild VeidahlAbstract
Two years of heavy defoliation of Pinus sylvestris by Neodiprion sertifer caused a volume loss of 33 % during a 9-year period after the defoliation of 90-120 years old pine forests. This loss corresponds to 3 normal annual increments. The increment losses in height, diameter and basal area are calculated both for the old stands and a young one (40 years of age). The economic consequences of the growth loss are also calculated and discussed.