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.
2010
Abstract
Scots pine (Pinus sylvestris) and especially its heartwood is one of the most common construction materials for general outer use e.g. windows or facades in northern Europe. It is considered being use class 3 and is according to EN 350-2 \"not treatable\". Reports from industry and researchers indicate that the heartwood treatability is not uniform. It is still unclear what causes these differences. To increase its durability by means of impregnation would be a contribution to extend the use of both a natural and native material. The understanding of a potential pattern analog to latitudinal/longitudinal origin or other forest or wood properties could help to improve the impregnation by better material selection. Scots pine samples from 25 different sites in 6 countries in northern Europe have been collected throughout autumn and winter 2009/2010. A circle of varying size containing approximately 30 trees was set up in a representative site of each stand. All diameters were measured and arranged in three classes. Three trees of each class were chosen randomly. Only the middle and upper diameter classes were used for studying heartwood permeability. The small diameter class had insufficient heartwood width to be processed. Samples of 20 x 20 x 50 mm were cut and conditioned in a climate chamber. The samples were impregnated with a water-soluble monomer furfuryl alcohol solution in a standard pressure/vacuum process. Results showed a generally low permeability but a few samples had an unexpected high ration of filling. Further on, the samples with the highest and lowest treatability will undergo anatomical and chemical tests to explain these properties.
Abstract
There is great ecological, economic and social value within forest genetic resources – that is a fact. But so far, the true legal status of this resource has not been defined. This was the background for a meeting held in Vienna on 13 September 2010 which assembled forest and legal experts to discuss preliminary outputs from a NordGen project (2009-2010), initiated by representatives from Denmark, Finland, Norway and Sweden....
Authors
Erlend Nybakk Meelis Teder Bill Slee Liana Sadauskiene Anssi Niskanen Anders Lunnan Krzysztof Jablonski Diana Feliciano Gabriel Duduman Fahrudin BajricAbstract
No abstract has been registered
Abstract
The Pasvik River valley is the easternmost part of Norway, and borders to Finland and Russia. In Norway it is known for its wilderness and taiga forests. During the 1960-1970s most of the mature pine forests were harvested, and large areas of pine stands have been naturally regenerated. In addition, large areas are covered with birch. The Pasvik River valley and the adjoining areas are therefore important both as an area for growing timber resources and for recreation. However, these areas have also been exposed to air pollution from Russian smelting industry since the 1930s. In addition to sulphur dioxide, emissions consist of various heavy metals which contaminate the surroundings. The main pollution source is the huge nickel plant in the Russian city Nikel, located only 10 km from the Norwegian border. For a long time there was general concern for the quality of the forest ecosystems in these areas. This concern accelerated in the mid-1980s.
Abstract
Concentrations of dissolved organic carbon (DOC) in throughfall and soil solutions at 5, 15 and 40-cm depth were studied in 16 Norway spruce and two Scots pine plots throughout Norway between 1996 and 2006 (Wu et al. 2010a). Average DOC concentrations ranged from 2.3 to 23.1 mg/l and from 1.1 to 53.5 mg/l in throughfall water and soil solutions, respectively. Concentrations of DOC in throughfall and soil waters varied seasonally at most plots with peaks in the growing season. In contrast to reported positive long-term trends in DOC concentrations in surface waters between 1986 and 2003, soil water data from 1996 to 2006 showed largely negative trends in DOC concentrations and no significant trends in throughfall. However, regression analysis for individual sites, particularly at 5- and 15-cm soil depths, showed that DOC concentrations in soil water were significantly and negatively related to non-marine sulphate and chloride. Further studies were carried out on dissolved organic nitrogen (DON, Wu et al. 2010b). Dissolved organic nitrogen (DON) concentrations were significantly and positively correlated to DOC concentrations in throughfall (r2=0.72, p<0.0001) and soil water at 5, 15, and 40 cm (r2=0.86, 0.32, and 0.84 and p<0.0001, 0.04, and <0.0001, respectively). At most sites, the annual median DOC/DON ratio in throughfall ranged from 20.3 to 55.5, while values in soil water were higher, ranging from 24.5 to 81.3 but gradually decreasing with soil depth. DON concentrations varied seasonally in throughfall at many plots and in soil water at 5 cm depth at one plot only, with higher values in the growing season, but there was no noticeable seasonality at greater depth. The ratios of DOC/DON in soil water were significantly positively related to the C/N ratio in soil at the same depth. Above-ground litter input was the main factor having a significant, negative relationship to DOC/DON in soil water at all depths studied. This might reflect the effect of site conditions on both DOC/DON ratios and litter quantity. A comparison of DOC and DON concentrations and fluxes at two Norwegian sites (Birkenes and Hirkjølen) and five Finnish Level II plots (Tammela, Juupajoki, Uusikaarlepyy, Kivalo and Pallasjärvi) showed no obvious correlation between concentrations and site and stand properties such as growing season length, temperature, precipitation, stand age, or soil C or N. DOC concentrations in the O horizon could not be linked to N deposition. However, there were clear within-site seasonal trends, compatible with an effect of temperature on microbial activity.
Authors
Hans Haavardsholm Blom Louise LindblomAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Knut Rydgren Jørn-Frode Nordbakken Ingvild Austad Inger Auestad Einar HeegaardAbstract
Seminatural grasslands and their species and populations are declining rapidly throughout Europe, bringing about a need for successful vegetation recreation methods. To maintain biodiversity and ecological services of seminatural grasslands, we need more nowledge on the relative performance of different recreation methods. In a replicated experiment in western Norway, we evaluated two hay transfer methods (hard or light raking of local hay), sowing of local seeds and natural regeneration for recreating seminatural grassland in a road verge. We compared treated trial plots with their respective donor plots (where hay and seeds were harvested) for three successive years by evaluating vegetation cover, species richness and species transfer rates, and vegetation dynamics analysed by Bray–Curtis compositional dissimilarity (BC) and GNMDS (Global NonMetric Multidimensional Scaling) ordination. Vegetation cover at the trial site exceeded that of donor sites in three years. Transfer rates of common species were high for seed sowing and both hay transfer procedures. Species composition in trial plots for all three treatments became significantly more similar to donor plots, but was still relatively dissimilar after three years. Natural regeneration showed a different temporal pattern and also had a higher successional rate. The species composition of the other treatments followed the same trajectory toward the donor sites as revealed by GNMDS. We found relatively small differences between the two hay transfer methods and seed sowing. Transfer of local hay therefore appears to be a successful method of establishing local species when recreating seminatural grasslands, and is generally cheaper than using commercial local seed mixtures.
Authors
Jørn-Frode Nordbakken Knut Rydgren Inger Auestad Ingvild AustadAbstract
This study focused on a suite of vascular plant species (six herbs and two grasses) common to traditionally managed, species-rich grasslands in Western Norway. We assessed the suitability of two species transfer methods (seed sowing and soil seed bank) for restoration of species-rich grassland on a newly established road verge. We compared the species\" frequencies one and three years after they were sown on a naked, newly created road verge with their frequencies in aboveground vegetation and soil seed banks of comparable, local grasslands. Species frequencies in the aboveground vegetation differed significantly from those in the seed banks. Moreover, the frequencies in the seed banks differed from those recorded one year after sowing, and the frequencies in the aboveground vegetation differed from those recorded three years after sowing. Avenula pubescens and Knautia arvensis, found in more than 25% of the aboveground grassland plots, did not germinate from any of the seed bank samples. Festuca rubra, Galium verum, Pimpinella saxifraga and Silene vulgaris were more frequent in the aboveground plots than in the seed bank samples. Pimpinella saxifraga, Galium verum and Lychnis viscaria emerged quite well both from sown seeds and from the seed bank. Avenula pubescens was frequent in the aboveground vegetation, but did not germinate from sown seeds. Six species established well from seeds, and most increased in frequency in the sown plots from the first to the third year. No species was found in the sown plots only, but three years after sowing, three species were more frequent in the sown plots than in the aboveground vegetation of donor grassland plots. Our fine-scale, point-to-point study demonstrates that different restoration methods produce widely differing species composition even when the donor material is identical. We propose that different substrates and a combination of establishment methods (sowing and hay transfer) are needed as supplements to seed banks to re-establish species-rich grassland.
Authors
Kjell Andreassen Birger Solberg Øyvind JacobsenAbstract
Four forest management systems, clear cutting, mountain forest selective cutting (50-90 % of volume removed), group system and single tree selection system (20-50 % of volume removed) were compared in two Norway spruce mountain forest stands. The sites are located 650 m.a.s.l., which is about 100 meter below the alpine tree line in this region. The background for this experiment was that the forest owner wanted to examine alternatives to clear cutting with silvicultural methods where some trees were left in the stand to protect regenerating against frost, to maintain biodiversity, and for recreational reasons in such areas close to the tree line. In twenty 400 m2 systematically sampled plots we assessed or measured vegetation type, regeneration, diameter of all trees > 2.5 dbh, tree heights, annual growth from increment cores, tree quality, old stumps and windthrows. In addition, time studies of the four harvesting methods were performed close to each other in the area. The following mean values were estimated in the two stands before cutting: Area 7 hectares, volume 170 m3/ha, mean diameter 23 cm, mean height 18 m, stems 550/ha, seedlings 150/ha, productivity 3 m3/ha/yr. The diameter distribution of the two stands was almost similar to a reverse J-shaped curve, but a larger amount of trees in some medium and large diameter classes were observed. However, most of the 230 m3 harvested trees were medium and large sized. Annual increment indicated growth reactions 3 years after harvesting. The operational costs were estimated according to time studies of the harvesting and extraction of 580 trees. Analyses of net present value, where bare land value and all future revenues and expenses were estimated and discounted backwards to the harvesting year, indicates less profitability for group selection and selection system than clear cutting and mountain forest selective cutting.