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.
2008
Abstract
In Norway exterior wood structures have traditionally nearly exclusively been made of treated and untreated Picea abies and Pinus sylvestris. 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 main objective of this paper is to evaluate natural durability of Norwegian wood species for above ground applications comparing two non-standard above ground tests with the European standard tests for soil contact (EN 252) and lab performance against basidiomycetes (EN 113). The European standard tests EN 113 and EN 252 gave quite similar results, and they also corresponded well with the natural durability classification in EN 350-2. The two non-standard above ground tests differed to some extend from EN 113, EN 252 and EN 350-2. The results indicate that natural durability classification for one single wood species can change depending on use class. However, the field trials need a longer period of time before a final classification can be performed. Four species not included in EN 350-2 were classified in this study: Juniperus communis (1), Salix caprea (5), Sorbus aucuparia (5) and Populus tremula (5).
Abstract
In this project plant and vegetation preferences of two Norwegian dairy cattle breeds with different selection history were studied. The Norwegian dairy breed Blacksided Trønder and Nordland Cattle (STN) has never been selected efficiently for higher milk production. The other breed, however, the Norwegian Red (NR), has mainly been selected for this. Two herds both consisting of STN and NR cows, were studied. To examine the animals\" plant preferences, faeces samples were collected and analysed for plant fragments. Vegetation maps were also used to find possible differences in grazing preferences. Breed differences with regard to recorded plant fragments in the faeces samples were significant for Nardus stricta, a species characteristic for nutrient poor but mostly species rich vegetation types in the studied areas, vegetation types of high importance for the biodiversity especially in one of the areas. STN had the highest share of Nardus stricta. Altogether the results of the study indicate that a higher producing cattle breed might prefer to graze more nutrient rich vegetation areas compared to a lower yielding cattle breed, when grazing less nutrient and base rich - but species rich grasslands.
Abstract
Wood for outdoor decking has a high marked share in the Nordic and Baltic countries among private house owners. Important issues for the consumer are maintenance intervals and aesthetic appearance as well as decay resistance. Knowledge and consumer information about these aspects are required to ensure that wood can compete with alternative decking materials. In this paper an accelerated testing of decking, “stapelbäddsmetoden”, was evaluated after six years of exposure at Ås, Norway, and compared with earlier reported results after three years. Twelve different preservatives and wood modification treatments were used in addition to untreated Scots pine (sapwood and heartwood) and larch (heartwood). The samples were treated with two different surface treatments. In addition there was one set without any surface treatment. In this method for accelerated testing, discolouration and decay was evaluated. This provided new information about performance both on and above ground for a range of different combinations of preservative/modified systems and surface treatments of wood in decking for outdoor use. For example, no clear differences were found between the surface treatments and no surface treatment. The wood modifications with styrene and furfurylalcohol performed just as good, or better, than the copper containing treatments.
Authors
Sebastian EiterAbstract
Anmeldt bok: Price, Martin F. editor, 2007. Mountain area research and management: integrated approaches. Earthscan, Sterling, Virginia. xiv + 302 p. $95.00, ISBN: 978-1-84407-427-3.
Abstract
No abstract has been registered
Authors
Nenad Kea Halvor SolheimAbstract
No abstract has been registered
Authors
Jan Stenlid Matteo Garbelotto Ursula Kües James B. Anderson Francis Martin Halvor SolheimAbstract
No abstract has been registered
Authors
Tao Zhao Anna-Karin Borg-Karlson Bo Långström Halvor Solheim Erik ChristiansenAbstract
Induced reactions in the phloem is a basic mechanism of conifer resistance to bark beetle and their associated fungi (1,2). Previous research has proved that certain doses of Ceratocystis polonica infection or methyl jasmonate (MeJA) application could induce acquired resistance and decrease subsequent fungal or bark beetle colonization (3,4,5). To study the induced chemical changes after fungal infection and MeJA application in the phloem of mature Norway spruce, three groups, each of 24 P. abies trees of similar size, were chosen in Tönnersjöheden, southern Sweden, in May 2006. The three groups were then inoculated with C. polonica, sprayed with MeJA, or used as untreated control, respectively. Phloem samples were taken twice from each tree: on the same day as treatment and 1 mo later. The terpene composition of all the samples was analyzed by GC-MS, and the enantiomeric compositions of α-pinene, β-pinene, and limonene were analyzed by 2D-GC (6). The result indicated that both MeJA application and C. polonica infection had certain effects on the terpene composition. C. polonica infection significantly increased the biosynthesis of 3-carene, sabinene, and terpinolene. Both mean absolute amounts and relative amounts of these monoterpenes increased in samples from fungus inoculated trees, similar to what is observed in Scots pine after Leptographium wingfieldii inoculation (7). MeJA application increased the absolute amount of α-pinene, β-pinene, limonene, and some other major terpenes, but it did not change the relative amount of these terpenes. However, neither MeJA application nor fungal infection changed the enantiomeric compositions of α-pinene, β-pinene, and limonene in the phloem of Norway spruce.
Authors
Rimvydas Vasaitis Bo Långström Halvor Solheim Ylva Persson Katarina Ihrmark Jan StenlidAbstract
Ips typographus is economically most important insect pest of mature spruce in Eurasia. Normally, it prefers to reproduce in dead and/or dying trees, but following large-scale storm disturbances, its outbreaks kill waste areas of living stands. One factor triggering such epidemics is a surplus of broken and uprooted trees with non-existent, or weak, defence....
Authors
Haiying Liu Tonje Økland Rune Halvorsen Jixi Gao Quanru Liu Odd Eilertsen Harald BratliAbstract
Monitoring of ground vegetation and environmental variables in subtropical forests in China was initiated in 1999 as part of the “Integrated Monitoring Programme of Acidification of Chinese Terrestrial Systems”. The study areas were selected to span regional gradients, in deposition of airborne pollutants and climatic conditions. All five study areas are located in the southern and south-western parts of China and consist of subtropical forests. In each study area 50 1-m2 plots were randomly chosen within each of ten 10×10 m macro plots, each in turn positioned in the centre of 30×30 m extended macro plot. All 250 1-m2 plots were subjected to vegetation analysis, using frequency in subplots as measure of species abundance. A total of 33 environmental variables were recorded for 1-m2 plots as well as 10×10 m macro plots. A major objective of this study is to identify the environ¬mental variables that are most strongly related to the species composition of ground vegetation in S and SW Chinese subtropical forests, as a basis for future monitoring. Comparison among DCA, LNMDS and GNMDS ordination methods, an additional objective of the study, was achieved by using a set of different techniques: calculation of pair-wise correlation coefficients between corresponding ordination axes, Procrustes comparison, assessment of outlier influence, and split-plot GLM analysis between environmental variables and ordination axes. LNMDS and GNMDS consistently produce very similar ordinations. GNMDS ordinations are generally more similar to DCA than LNMDS to DCA. In most cases DCA, LNMDS and GNMDS extract the same main ground vegetation compositional gradients and the choice of LNMDS or GNMDS is therefore hardly decisive for the results. GNMDS was chosen for interpretation and presentation of vegetation-environment relationships. The dimensionality of GNMDS (number of reliable axes) was decided by demanding high correspondence of all axes with DCA and LNMDS axes. Three dimensions were needed to describe the variation in vegetation in two of the areas (TSP and LXH), two dimensions in the other three areas (LCG, LGS and CJT). Environmental interpretation of ordinations (identification of ecoclines; gradients in species composition and the environment) was made by split-plot GLM analysis and non-parametric cor¬relation analysis. Plexus diagrams and PCA ordination were used to visualize correlations between environmental variables. Several graphical means were used to aid interpretation. Complex gradients in litter-layer depth, topography, soil pH/soil nutrient, and tree density/crown cover were found to be most strongly related to vegetation gradients. However, the five study areas differed somewhat with respect to which of the environmental variables that were most strongly related to the vegetation gradients (ordination axes). Litter-layer depth was related to vegetation gradients in four areas (TSP, LCG, CJT and LXH); topography in four study areas (TSP, LGS, CJT and LXH); soil pH in three areas (LCG, LGS and CJT); soil nutrients in one area (LGS); and tree density/crown cover in one area (LCG). The ecological processes involved in relationships between vegetation and main complex-gradi¬ents in litter-layer depth, topography, soil pH/soil nutrient, and tree density/crown cover, in subtropical forests, are discussed. We find that gradient relationships of subtropical forests are complex, and that heavy pollution may increase this complexity. Furthermore, our results suggest that better knowledge of vegetation-environment relationships has potential for enhancing our understanding of subtropical forests that occupy vast areas of the S and SW China.