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.
2005
Abstract
At least three mechanisms are known to cause synchrony among spatially separated insect populations: 1) dispersal among populations, 2) synchronous stochastic effects, often referred to as the Moran effect, and 3) trophic interactions with other species that are either themselves synchronized or mobile.The present study brings in the role of insect taxa for spatial synchrony. The spatial synchrony observed in several North American and Eurasian epidemic bark beetles was compared with patterns of synchrony in outbreaks of defoliating forest Lepidoptera, revealing a marked difference between these two major insect taxa.The bark beetles exhibited a generally lower degree of spatial synchrony than the Lepidoptera, possibly because bark beetles are synchronized by different weather variables that are acting on a smaller scale than those affecting the Lepidoptera, or because inherent differences in their dynamics leads to more cyclic oscillations and hence more synchronous spatial dynamics in the Lepidoptera. Among the epidemic bark beetles tested, spatial synchrony of outbreaks in the Eurasian spruce bark beetle Ips typographus was significantly higher than for the other species.
Abstract
Wood samples treated with ammonium copper quat (ACQ 1900 and ACQ 2200), chromated copper arsenate (CCA), Tanalith E 3491 and Wolmanit CX-8 have been studied in accelerated weathering experiments. The weathering experiment was performed by cycles of 2 h UV-light irradiation followed by water spray for 18 min. The changes on the surface of the weathered samples were characterized by roughness and color measurements on the samples with 0, 200, 400 and 600 h of total weathering.The objective of this study was to investigate the changes created by weathering on impregnated wood with several different wood preservatives. This study was performed on the accelerated weathering test cycle, using UVirradiation and water spray in order to simulate natural weathering. Surface roughness and color measurement was used to investigate the changes after several intervals (0200400600 h) in artificial weathering of treated and untreated wood.
Authors
Harald Kvaalen Ola Gram Dæhlen Anne Tove Rognstad Borgny Sveen Grønstad Ulrika EgertsdotterAbstract
Seeds of Abies lasiocarpa (Hook.) Nutt. (subalpine fir) were dissected, and the different parts were analyzed for elemental composition. The data were used to design a novel growth medium for initiation of somatic embryogenesis. Embryogenic cultures were initiated from immature zygotic embryos from six open-pollinated families of A. lasiocarpa on three different media.The frequency of initiation was the highest in early to mid-July when the zygotic embryo explants were ca. 0.8 mm long. Thereafter the response declined rapidly.The culture media did not significantly affect the initiation frequencies, but the subsequent growth and culture survival was dependent on the culture medium. On the Schenk Hildebrandt medium, many cultures ceased to grow and died. Several of the decaying cultures were rescued after transfer to one of the new media. Proliferating cultures could be stimulated to produce mature embryos. Of 2510 mature somatic embryos, 212 (8.4%) converted to plants, and 35 plants have grown over two periods.
Authors
Kåre Olav VennAbstract
No abstract has been registered
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No abstract has been registered
Authors
Per Gundersen Jan-Olov Weslien Bjarni D. Sigurdsson Magne Sætersdal Leena Finér Ingeborg CallesenAbstract
Forest ecosystems provide many deliverables or benefits to society. The most obvious one is wood for the forest industry. Other benefits include berries, hunting, and recreation. More recently recognised benefits are environmental services such as carbon sequestration, water protection and biodiversity, which are without an immediate market value.On the other hand, there are pressures (e.g. climate change, air pollution, exploitation, and costs) on the ecosystem that may hamper the wood production or other benefits......
Abstract
No abstract has been registered
Authors
Erlend Ystrøm Haartveit Line HoemAbstract
Mergers and acquisitions have lead to an increase in company size for manufacturers as well as for distributors and retailers of structural lumber. The effect of this mutual dependency in customer-supplier relationships increases, opening for opportunities to search for efficiency improvements across company borders.This article report the findings from a case study involving a major lumber manufacturing corporation in Norway and its largest customer, a vertically integrated distributor and home improvement retailer. In particular, the order process extending from identification of demand at the retail store to fulfilment of demand was comprehensively mapped, and possible areas for improved efficiency in the supply chain were identified.Using this approach, simple solutions for process improvement are commonly found, simply because individual actors rarely focus on optimising the complete supply chain, but rather sub-optimise a small fraction of the chain.The article also discusses some of the problems encountered when developing measures of performance intended to monitor and improve the process across company borders. Creating measures for monitoring performance is technically and methodologically difficult when dealing with several actors in a complex system using different business systems. The challenge greatly increases when the actors business objectives and philosophies are traditionally conflicting.
Authors
Karl Hilding Thunes R.F. Billings Lawrence R. KirkendallAbstract
De pågående masseangrep av Dendroctonus spp. startet mer eller mindre synkront i alle sentralamerikanske land sent i 1998 og tidlig i 1999; epidemien har hittil ødelagt flere hundre tusen hektar furuskog i Mexico, Belize, Guatemala, Honduras og Nicaragua, og i et mindre omfang El Salvador. Til tross for at landene er små, er naboer og har den samme insektfienden er samarbeid over landegrensene omtrent fraværende. Hele skadebildet og omfanget er også en direkte trusselmot det sterkt truete furu-eik økosystemet i regionen. Et felles regime for forvaltning av furuskogene og deres skadegjørere bør bli utviklet for fremtiden, men koordinert aksjon for å stoppe billene blir forhindret av forskjeller i styrke, kapasitetog mandat hos de forvaltende institusjoner i hvert land. Likevel, omfanget og alvoret i den pågående epidemien har resultert i flere bilaterale og regionale initiativer, og lagt grunnen for formelle, langvarige regionale samarbeidsprogrammer i forvaltningen av denne viktige biologiske ressursen.
Abstract
No abstract has been registered