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.
2009
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No abstract has been registered
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No abstract has been registered
Authors
Mari Mette Tollefsrud Jørn Henrik Sønstebø Christian Brochmann Øistein Johnsen Tore Skrøppa GG VendraminAbstract
No abstract has been registered
Abstract
Modified wood is commercially available and merchandized as a new, environmentally friendly and durable wood species. However, there are no standards focusing on the evaluation of modified wood. Combining resistance against fungal decay and good ecotoxicological properties may be a start. In this study softwood and hardwood species were furfurylated using different treatment processes and treating solutions. The durability was determined by exposing the treated wood to a range of Basidiomycetes and the ecotoxicity was studied on two aquatic organisms.It was the purpose to come to a strategy and how to unite efficacy and ecotoxicity, since this is important in product development. The results show that the selection of fungus used for mass loss determination and the choice of ecotoxicity method is decisive, confirming that a combination of methods is valuable. A tiered approach to find the optimal treatment seems the best option. First, adequate protection against wood-rotting fungi should be attained, followed by ecotoxicity evaluation of the wood leachates. If necessary, the optimization process should be repeated until both durability and ecotoxicity are within satisfactory limits. This process could be extended with other evaluation criteria, e.g. dimensional stability of the modified wood or a risk analysis of its leachate.
Authors
Randi Therese Garmo Erik Ropstad Øystein Havrevoll Erling Thuen Håvard Steinshamn Andres Waldmann Olav ReksenAbstract
Relationships among commencement of luteal activity (C-LA), milk yield, and energy balance (EB) were investigated in 3 selection lines of Norwegian Red cows at the Norwegian University of Life Sciences from 1994 through 2001. The cows were selected for low genetic merit for milk yield (LMP), high genetic merit for milk yield (HMP), and a combination of high indices for milk yield and fertility (HI). Breeding values for fertility were based on 56-d nonreturn rate. The material included 268 lactations from 147 cows. Milk samples for progesterone analysis were drawn 3 times weekly from 1994 through 1998, and 2 times weekly from 1999 to 2001. Commencement of luteal activity was defined as the first 2 consecutive measurements of progesterone concentration > 3 ng/mL not earlier than 10 d after calving. Selection line was significantly related to C-LA, so that the least squares mean days from calving to C-LA were 22.5, 30.4, and 27.2 d for LMP, HMP, and HI cows, respectively. The HMP cows produced more milk than the LMP cows. The average milk yield in the sixth week of lactation was 24.0, 27.1, and 25.3 kg for LMP, HMP, and HI cows, respectively. The interval to C-LA decreased for the HMP and HI cows after phenotypic adjustment for EB in the model. Least squares means for the interval to C-LA were 23.2, 29.7, and 25.6 d for the LMP, HMP, and HI cows, respectively, in a model that included parity, selection lines, and EB as covariates. Cumulated EB during the first 4 wk of lactation, which itself differed between selection lines, did not fully account for differences in interval to C-LA between selection lines. Thus, the results of the present investigation indicate that selection for milk yield negatively affects C-LA over and above the effects caused by concurrent changes in EB. The increase in days to C-LA caused by selection for high yields can be reduced if selection for milk yield is combined with fertility in the breeding program.
Authors
Nils Vagstad Helen French H.E. Andersen H. Behrendt B. Grizzetti P. Groenendijk A. Lo Porto H. Reisser C. Siderius J. Stromquist J. Hejzlar Johannes DeelstraAbstract
No abstract has been registered
Abstract
The durability of wood in exterior use is limited by to climatic factors and wood deteriorating organisms. The natural durability of the Nordic wood species is generally regarded as low, and for e.g. decking and use in soil contact wood protection is needed. Within the last years, new non-biocidal treatments, like wood modification systems, have been developed to improve the biological resistance of wood. For information about the decay resistance of untreated and modified wood, natural outside exposure is necessary. European standard EN 252 is the main field test method for use class 4. In use class 3 the need of new or improved test setups has been put forward. Traditionally evaluation of field trials has mainly been based on visual evaluation and pick-test. However, to get in depth knowledge about: 1) different field trial methods and 2) fungal colonization of new wood protection systems, additional assessment methods can be used. Hence, comparative studies are needed.....
Authors
Kjersti Holt HanssenAbstract
We studied the growth of Norway spruce and Scots pine seedlings in the understory, using three sites with selective cutting and group fellings in SE Norway. Seedlings were planted in plots with and without trenching in gaps of four different sizes, ranging from 20 m2 to 500 m2 and giving light levels from around 20 to 75 % of open sky. After tree years seedlings were dug up and measured. Vegetation cover was also registered. Growth of both species was positively and significantly correlated with increasing gap size. This applied for height, diameter, shoot volume, needle length and needle number as well as total dry weight. However, trenching also had a clear and significant positive effect on the same growth parameters. The growth of some weed species, especially wavy hair-grass (Deschampsia flexuosa) also increased significantly with both gap size and trenching. The results show that competition for both light and below-ground resources matters for understory seedling growth under the studied conditions.
Authors
Stig Strandli GezeliusAbstract
No abstract has been registered
Authors
Knut Anders Hovstad Mikael OhlsonAbstract
Plant litter is an important determinant of seed germination and seedling establishment. Positive effects of litter have received considerable attention, but few studies have explicitly tested whether seedlings are more facilitated by conspecific litter compared to heterospecific litter. In order to contrast conspecific and heterospecific facilitative effects on seedling establishment, we used Anthriscus sylvestris, Angelica sylvestris, Pimpinella saxifraga and different combinations of their seeds and litter seedbeds as a model system. Although litter had a significant species-specific effect on seedling emergence, we found no evidence of strictly conspecific facilitation. Anthriscus sylvestris displayed a positive response to all types of litter. In contrast, there was a clear negative effect of conspecific litter in Pimpinella saxifraga. Activated carbon did not modify the negative effect, indicating that chemical compounds were not the cause. Our study suggests a high level of idiosyncrasy in response to litter at the species level.