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.
2013
Abstract
No abstract has been registered
Abstract
Top-dieback of Norway spruce (Picea abies) trees has been observed in SE Norway. Trees usually die within 1-4 years after the first symptoms become visible and the dieback cause is unknown. The aim of our study was to establish when the irreversible spiral to tree death occurs. We assumed that hydraulic dysfunction, exemplified here by the sap flow reduction, was the final trigger of tree decline. We used the non-destructive heat field deformation method (HFD) to monitor the sap flow density (SFD) in non-symptomatic trees. After felling the trees we used the modified differential translucence method (MDT) to evaluate the sapwood translucence as an additional indicator of its functionality. In this study we show three examples of non-symptomatic trees with widely different sap flow densities detected by the HFD; tree A with unchanged sap flow throughout the monitoring period, tree B with decreasing sap flow in the last formed annual rings and minimal sap flow detected in tree C, which also started to show the first visible signs of dieback. In contrast, the MDT method detected in all cases functional (translucent) sapwood. In conclusion, we show that the sap flow reduction may occur during a relatively short period, prior to occurrence of any visual symptoms. Also, dysfunctions in sap flow could not be detected by the MDT method, as the sapwood still looked translucent and thus functional, although minimal sap flow was detected in that area by HFD method. Here we demonstrate the sensitivity of the HFD method in detecting the quantity of sap flow and thus a suitable diagnostic tool to evaluate the vitality in Norway spruce trees before the onset of visible disease symptoms.
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No abstract has been registered
Authors
Marte MelandAbstract
No abstract has been registered
Authors
Marte MelandAbstract
No abstract has been registered
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Tourism is acknowledged to be an important business sector in rural areas. This paper argues that second-home owners constitute an important market segment for businesses that offer nature-based tourism activities. Previous research has shown that a number of factors influence tourist behaviour. This study examined how motivation and demographic variables affect second-home owners\" intention to purchase three different types of activity products: learning, adventure, and hunting products. We found substantial variations in the purchase intentions for these products among second-home owners. These intentions were influenced by push and pull motivations, age, income and educational level. Second-home owners with a high intention of purchasing nature-based tourism activity products tend to be young, high-income, and socially oriented risk takers. Businesses offering nature-based tourism activity products should use a combination of demographic and psychographic variables when they segment the second-home market. Highlights The second-home market is important for nature-based tourism businesses. Their intention to purchase such products are influenced by leisure motives and demographic variables. Recreation experience preferences and reasons for having a second-home in an area influence their purchase intentions. Age and education level have a negative effect on the intention to purchase. Income has a positive effect on the intention to purchase.
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No abstract has been registered
Authors
JC. Streibig J. Rasmussen D. Andùjar Therese With Berge D. Chachalis T. Dittmann R. Gerhards TM: Giselsson P. Hamouz C. Jaeger-Hansen K. Jensen RN. Jørgensen M. Keller M. Laursen HS Midtiby J. Nielsen S. Muller H. Nordmeyer H. Peteinatos A. Papadopolous J. Svensgaard M. Weis S. ChristensenAbstract
No abstract has been registered
Authors
Sarah Hale John Jensen Lena Jakob Patryk Oleszczuk Thomas Hartnik Thomas Henriksen Gudny Okkenhaug Vegard Martinsen Gerard CornelissenAbstract
The aim of the present study was to evaluate the secondary ecotoxicological effects of soil amendment materials that can be added to contaminated soils in order to sequester harmful pollutants. To this end, a nonpolluted agricultural soil was amended with 0.5, 2, and 5% of the following four amendments: powder activated carbon (PAC), granular activated carbon, corn stover biochar, and ferric oxyhydroxide powder, which have previously been proven to sequester pollutants in soil. The resulting immediate effects (i.e., without aging the mixtures before carrying out tests) on the springtail Folsomia candida, the earthworm species Aporectodea caliginosa and Eisenia fetida, the marine bacteria Vibrio f ischeri, a suite of ten prokaryotic species, and a eukaryote (the yeast species Pichia anomalia) were investigated. Reproduction of F. candida was significantly increased compared to the unamended soil when 2% biochar was added to it. None of the treatments caused a negative effect on reproduction. All amendments had a deleterious effect on the growth of A. caliginosa when compared to the unamended soil, except the 0.5% amendment of biochar. In avoidance tests, E. fetida preferred biochar compared to all other amendments including the unamended soil. All amendments reduced the inhibition of luminescence to V. f ischeri, i.e., were beneficial for the bacteria, with PAC showing the greatest improvement. The effects of the amendments on the suite of prokaryotic species and the eukaryote were variable, but overall the 2% biochar dose provided the most frequent positive effect on growth. It is concluded that the four soil amendments had variable but never strongly deleterious effects on the bacteria and invertebrates studied here during the respective recommended experimental test periods.