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.
2009
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Josef Eitzinger Sabina Thaler Simone Orlandini Pavol Nejedlik Valentin Kazandjiev Tor Håkon Sivertsen Dragutin MihailovicAbstract
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Christian Guido Bruckner Peter, G. KrothAbstract
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Analysing forest history is crucial to understanding how shifting harvesting methods have different effects on forest landscape structure. Two main harvesting regimes in a Norwegian boreal forest landscape over a period of 150 years were detected by the study. A homogeneous impact regime resulting from selective logging changed the forest structure by logging the oldest and largest trees evenly throughout the forest, resulting in a homogeneous landscape structure. However, population growth in the 19th century led to a substantial increase in traditional subsistence forestry to obtain building materials, firewood, etc. The most intensive stage of this regime started in c.1860 when farmers began selling logging contracts to companies and timber traders. Despite this being termed a homogeneous landscape impact, the actual exploitation of the forest was strongly influenced by local factors such as the location of farms, summer farms, lakes, and rivers. Clear-cutting from the 1950s has resulted in a new heterogeneous impact regime, giving a landscape structure dominated by patches of even-aged stands. This regime still predominates. The analysis is based on a study of Nordli and the Sandøla drainage basin in Nord-Trøndelag. Such studies should give a better understanding of the interaction between natural ecological conditions in and human impact on boreal forest landscapes.
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Stig Strandli GezeliusAbstract
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Nina JohansenAbstract
Continuous light is a promising method to reduce the problems with rose powderymildew in greenhouse rose production. The effects of such a light regime on the performance of insect pests on roses have so far not been investigated. In the present study, survival, developmental time, and reproduction during one generation of the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), were characterized on roses, Rosa x hybrida cv. Passion, grown in climate chambers with long-day conditions (L20:D4) or continuous light (L24:D0) at 21 oC and fluctuating relative humidity (mean 74%, range 47–96%). Whiteflies reared under continuous light had lower immature survival and fecundity and shorter female longevity than whiteflies reared under long-day conditions, but immature developmental time was only slightly affected. Life-table analysis showed that the net reproductive rate (Ro) and intrinsic rate of natural increase (rm) were reduced by 85 and 76%, respectively, and the time for the population to double its size (D) was 4.2 times longer under continuous light. Thismean that the whitefly population growth under continuous light was strongly reduced compared with the traditional light regime used in rose production.
Authors
Nils Vagstad Helen French H.E. Andersen H. Behrendt B. Grizzetti P. Groenendijk A. Lo Porto H. Reisser C. Siderius J. Stromquist J. Hejzlar Johannes DeelstraAbstract
No abstract has been registered