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
Ketil KohmannAbstract
Feeding by the Tarnished Plant Bug (Lygus rugulipennis Popp.) has caused severe damage in Norwegian nurseries. Large quantities of seedlings have been removed after sorting. The life cycle of the insect has been well studied and documented. This study was a first attempt to investigate how the seedlings develop after the insect attacks.The first visible sign of damage is the development of multiple terminal buds. Two-year-old containerised seedlings were planted and followed for four years. Before planting, the seedlings were sorted into three damage classes, (0) undamaged, (I) moderately damaged; up to ten fully developed buds, and (II) severely damaged; from ten to twenty small buds and without any dominant apical bud.The damaged seedlings were somewhat shorter at planting but this difference disappeared with time. The seedlings in the two damaged classes differed in their development of multiple shoots. At the end of the four-year period about 50 % of the seedlings in ClassII and about 20 % from Class I still had multiple leaders, or lateral stems or side branches that would probably in the future produce spike knots. The sorting routine currently used at the nursery was found to reduce the problem to an acceptable level for seedlings that were planted in the forest.
Abstract
No abstract has been registered
Abstract
In Norway exterior wood structures have traditionally nearly exclusively been made of treated and untreated Norway spruce (Picea abies (L.) Karst) and Scots pine (Pinus sylvestris L.). In recent years there has been a tendency that other tree species, like various domestic hardwoods and imported species have been used in exterior above ground applications, often unfinished. For several wood species, especially hardwoods, information regarding the durability in use class 3 is lacking. The test procedures prescribed in the European standards, both laboratory and field tests, have some weaknesses regarding to natural durability testing. Hence, some new methods for accelerated above ground testing have been put forward. The main objectives of this project are to evaluate natural durability of Norwegian wood species for above ground applications, and to study various methods for assessing decay in wood. This paper presents the material and methods used in the project, and report the results from double layer tests after one year of exposure. No decay was detected, but almost all wood species were considerably discoloured. Thuja (Norw.), Thuja (Am.), Intsia and Tectona had the least amount of discolouration. The Norwegian softwood species had generally less discolouration than the Norwegian hardwood species. CCA and Cu preservative impregnated and FA modified Pinus sylvestris sapwood had more cracks than most of the untreated wood species. Moreover, some of the Picea abies qualities and Pinus sylvestris sapwood samples had substantial amounts of cracks.
Authors
Birger VenneslandAbstract
During the 1980s and the 1990s the tourism development in general increased rapidly. The term innovation has been used to describe this development. But how well can we adapt the traditional industrial understanding of innovation in the service sector? Especially it seems as we have to extend our understanding of innovation when comes to the development of nature based tourism. There is a need to discuss various definitions of innovation and look at a framework of understanding that distinguishes between various definitions of innovation in the service sector.
Authors
Per Otto Flæte Erlend Ystrøm Haartveit Kjell VadlaAbstract
Considerable areas in the northern parts of Norway are afforested with Picea abies (L.) H.Karst. (Norway spruce), Picea × lutzii Little (Lutz spruce), and Picea sitchensis (Bong.) Carrière (Sitka spruce). The species have different machining and wood properties but are similar in visual appearance. We evaluated whether near infrared (NIR) spectroscopy combined with multivariate statistical modelling could be used to identify wood from these three species. In all, 83 wood specimens were available for analyses, 36 of which were used as a test set for model validation. NIR spectra were obtained on the cross-sectional surfaces. An initial principal component analysis showed that little information from the first and second components could be used for discrimination, but in score-plots of the third and fourth components the samples from the tree species formed clusters. This showed that the NIR spectra did contain information relevant for tree species identification, and that only a small fraction of the total variance could be used for that purpose. For classification of the wood specimens, partial least squares discriminant analyses were applied. All 47 specimens in the training set were fitted into the correct group. The test set validated results showed that except for two wood specimens, all specimens were correctly classified. The two misclassified samples were Sitka spruce. This study showed that development of well-performing rediction models for differentiation of wood from Norway spruce, Lutz spruce, and Sitka spruce is possible.
Authors
Ann Norderhaug John Eilif Hermansen Lena Bergils Sirpa Kurppa Anna Thorhallsdottir Line RosefAbstract
The Nordic Joint Committee for Agricultural Research (NKJ) promotes and supports cooperation between the Nordic Research Councils. The main goal for NKJ is to support a sustainable agricultural development. In June 2005 NKJ therefore decided to establish a working-group to follow up the Aukureyri declaration. This declaration focuses on the future tasks for Nordic agriculture and on the cultural landscape as a resource especially with regard to rural development. The working-group has given an account of Nordic research regarding use of the cultural landscape as a resource for sustainable agricultural development. Based on this the working-group give attention to needs for research and give recommendations for future Nordic agricultural research. Furthermore the workinggroup has evaluated different kinds of research cooperation.
Authors
Tor J. JohansenAbstract
No abstract has been registered
Abstract
This analysis is based on climatic data and increment cores from about 550 Forest officers from latitude 58-70N and longitude 6-18E. The strength of the data is the high number of plots scattering over most of the Norway spruce forest area in Norway. Tree ring-widths were transformed to ring indices to remove age disturbances and strengthen the climatic signal on the tree growth.We used regression analyses to examine the annually growth responses of these ring indices against 42 monthly climatic variables. The climatic variables we used were mean month temperature, precipitation and Palmer drought severity index (PDSI) with a range from previous year July to current years August.The results showed some correlations of climate on growth, with the June weather as most important. The most important variable in the lowlands (altitude 500 m) of southeastern Norway was the June precipitation, and the June temperature in the rest of the country.
Abstract
This study is based on data from the Level I and from forest Officers plots. We combined three sets of data on growth, deposition and soil chemistry, totally 204 plots in south-eastern and mid-Norway. As response variable we used observed growth in % of estimated growth calculated from standard Norwegian growth models. In this way we filtered out the influence of site and stand properties as this were included in the model.The dependent deposition variable used was the N deposition from the national air and precipitation monitoring program. The dependent soil chemistry variables were N, C/N ratio, base saturation, pH, Al, and Ca/Al ratio. Soil chemistry variables should reflect the properties that most likely are influenced by S and N deposition, and that could influence the trees in the hypothesised ways.We used analyses of covariance as statistical method. Growth was positively correlated to nitrogen deposition and to soil nitrogen, and negatively correlated to the C/N ratio in the soil. Also, nitrogen deposition was positively correlated to soil nitrogen and negatively to soil C/N.It was concluded that N deposition probably has increased N availability and thereby growth in southernmost Norway with an order of magnitude around 25%. There were no relationships between growth and the soil acidification variables pH, base saturation, Al concentration or Ca/Al-ratio, and we concluded that no evidence for negative effects of soil acidification on forest growth was found.
Authors
Volkmar TimmermannAbstract
No abstract has been registered