Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2016
Forfattere
Jørgen Todnem Tor LunnanSammendrag
Wavy hair-grass (Avenella flexuosa (L.) Drejer; Deschampsia flexuosa (L.) Trin.) is the main pasture species in blueberry mountain birch forest and dwarf birch – blueberry moorland, which cover large parts of outfield pastures in the mountainous region of Southern Norway. Blueberry mountain birch forest with continuous mats of A. flexuosa was fenced in and harvested at different times in the summers of 2014 and 2015. Regrowth was also recorded. The grass from sample plots was dried after harvest, and analyzed for feed quality using NIRS. There were no statistically significant differences in total net energy yield between different harvesting regimes. Grass growth was highest in early summer, and harvesting on 2 July gave about 60% of the seasonal yield. Grass yield in undisturbed population increased until the last harvest (early September). Regrowth after harvest was small at the end of the season, but the growth here corresponded with the growth in undisturbed population. A. flexuosa remained at vegetative stage during the season. The energy value was highest at harvest first in July, and relatively constant at later harvests. The protein concentration declined towards the end of the season.
Sammendrag
Uncoated wood is increasingly used in building façades in Northern Europe. The benefits can be both low maintenance and low environmental impact. An even, grey color of the façade is often the intention, but in several cases, an uneven pattern of light, grey and dark/black areas is the result. The effect of weathering and the influencing factors have to be considered when designing and building uncoated and coated wooden façade to avoid unwanted weathering effects. Wood weathering is commonly described to be caused by: accumulation of extractives on the surface, photo-degradation of lignin, staining by dark colored mould fungi, checking, cracking and splitting due to moisture fluctuation and erosion. This paper reviews, analyzes and exemplifies weathering as a finishing system and design option for uncoated wood. Furthermore, it also discusses and exemplifies the main influencing factors and weathering effects on coated wood in facades.
Sammendrag
Wooden elements may be subjected to mechanical, environmental or biological alterations during their service life. The most susceptible parts of wood structural members are the exposed surfaces since they are subjected to ageing, weathering and/or decay. Knowledge of the influence of weathering factors and polymer degradation mechanisms is essential for understanding the weathering process of wood. The goal of this study was to investigate the degradation of thin wooden samples exposed to short-term weathering. Tests were performed through the European summer (July), which according to previous research is considered as the most severe period for weathering of wood micro-sections. Fourier transform near infrared spectroscopy was used for evaluation of chemical changes of wood samples. Three approaches for data evaluation are presented in this paper: (1) direct spectral interpretation, (2) a concept for calculation of a weathering index Wind and (3) kinetics of lignin changes in relation to the exposure direction for selected wavelengths. Observation of the effects of weathering will allow better understanding of the degradation process. The southern exposure site was slightly more affected by weathering than other sites. Results of this research will be used for future determination of the weather-dose response model and could be essential for predicting the future performance of timber facade elements.
Forfattere
Sebastian EiterSammendrag
Det er ikke registrert sammendrag
Forfattere
Marte Holten Jørgensen Abdelhameed Elameen Nadine Hofman Sonja Klemsdal Sandra Malaval Siri FjellheimSammendrag
According to the Norwegian Diversity Act, practitioners of restoration in Norway are instructed to use seed mixtures of local provenance. However, there are no guidelines for how local seed should be selected. In this study, we use genetic variation in a set of alpine species (Agrostis mertensii, Avenella flexuosa, Carex bigelowii, Festuca ovina, Poa alpina and Scorzoneroides autumnalis) to define seed transfer zones to reduce confusion about the definition of ‘local seeds’. The species selected for the study are common in all parts of Norway and suitable for commercial seed production. The sampling covered the entire alpine region (7–20 populations per species, 3–15 individuals per population). We characterised genetic diversity using amplified fragment length polymorphisms. We identified different spatial genetic diversity structures in the species, most likely related to differences in reproductive strategies, phylogeographic factors and geographic distribution. Based on results from all species, we suggest four general seed transfer zones for alpine Norway. This is likely more conservative than needed for all species, given that no species show more than two genetic groups. Even so, the approach is practical as four seed mixtures will serve the need for restoration of vegetation in alpine regions in Norway.
Sammendrag
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Sammendrag
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Sammendrag
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Forfattere
Agnar KvalbeinSammendrag
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Sammendrag
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