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.
2013
Forfattere
Christian Brischke Linda Meyer Gry Alfredsen Mika Humar Lesley Francis Per Otto Flæte Pia Larsson-BrelidSammendrag
Besides its inherent resistance against degrading organisms, the durability of timber is infl uenced by design details and climatic conditions, making it diffi cult to treat wood durability as an absolute value. Durability classifi cation is, therefore, based on comparing performance indicators between the timber in question and a reference timber. These relative values are grouped and related to durability classes, which can refer to a high range of service-lives. The insuffi cient comparability of such durability records has turned out to be a key challenge for service-life prediction. This paper reviewed literature data, based on service-life measures, not masked by a durability classifi cation. It focused on natural durability of timber tested in the fi eld above-ground. Additionally, results from ongoing aboveground durability studies in Europe and Australia are presented and have been used for further analysis. In total, 163 durability recordings from 31 different test sites worldwide based on ten different test methods have been considered for calculation of resistance factors. The datasets were heterogeneous in quality and quantity; the resulting resistance factors suffered from high variation. In conclusion, an open platform for scientifi c exchange is needed to increase the amount of available service-life related data.
Forfattere
Håvard Steinshamn Ragnhild Aabøe Inglingstad Andrea Criscione Bernardo Valenti Marit JørgensenSammendrag
The objective of the present study was to examine the effect of grazing on different pasture types and hay feeding on dairy goat’s milk casein composition in early and late grazing season. Eighty goats were grouped according to genotype at the αS1-casein locus and number of lactations and randomly divided into two groups (Early and Late) with approximately 8 weeks difference in kidding dates. Goats within each of the two groups were further allocated to four forage treatment groups accounting for genotype and lactation number: R, forest rangeland pasture; C, cultivated pasture; HH, high quality hay; HL, low quality hay. The goats in Early were subjected to forage treatments in early grazing season, while the goats in Late received the forage treatments 8 weeks later. There was a strong effect of genotype but no genotype by diet interaction on casein content and composition. Goats grazing R yielded less milk (1.6 vs. 2.2 kg/d, P<0.001) with higher milk fat content (48 vs. 38 g/kg, P<0.001) than goats on C. Pasture type had no effect on total protein or casein content. However, milk from goats on R compared to C had lower content of αs1-casein (2.57 vs. 3.82 g/L, P<0.01) and κ-casein (4.51 vs. 5.22 g/L, P<0.05) but higher content of β-casein (13.1 vs. 11.7 g/L, P<0.001). Grazing compared to hay gave similar milk yield with higher content of total casein (24.2 vs. 21.0 g/kg, P<0.001), αs2-casein (3.48 vs. 3.04 g/L, P<0.001) and β-casein (12.4 vs. 11.7 g/L, P<0.01). Grazing compared to hay feeding improved the milk casein composition important for cheese making, while cultivated pasture were superior to rangeland.
Sammendrag
The relative volume growth effects of thinning after whole-tree harvesting (WTH) compared to a conventional stem-only harvest (CH) in young stands of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) were analyzed, using a series of four pine and four spruce field experiments. The series was established in the years 1972–1977, and thinning was performed only once. Results are shown periodically and cumulatively. All sites were included for 20 (19) years in pine and 25 years in spruce. The total experimental period varied between 19 and 35 years for individual sites. Four models assuming additive or multiplicative effects gave only slightly varying results. The inclusion of standing volume after thinning as a covariate was effective in spruce independent of whether the covariate was treated as multiplicative or additive. A logarithmic model with a multiplicative effect of the covariate was preferred in further presentations. Results for pine stands after 20 years indicated a nonsignificant loss of 5% with confidence limits (p = 0.05) of ±6–7%, while the spruce stands showed a significant growth loss of 11% with confidence limits of ±4–5% after 25 years. The difference between the species in relative growth effects was significant, and amounted to 8% for a cumulative 20-year period. No indications of trends in response were found during a 20-year period in pine and a 25-year period in spruce. An analysis of growth effects in the first years showed that basal area increment in spruce was significantly reduced already in the first growing season after thinning.
Sammendrag
To investigate the role of dehydrins (DHNs) in extreme low-temperature (LT) tolerance, we sampled needle tissue of Siberian spruce (Picea obovata Ledeb.) from trees growing in an arboretum in Trondheim, Norway from August 2006 to April 2007 and tracked changes in LT tolerance via relative electrolyte leakage. We used western blotting to estimate relative amounts of proteins binding a DHN K-segment antibody, measured relative amounts of nine transcripts for small (<25 kDa) DHNs by quantitative reverse transcription–polymerase chain reaction (PCR) using primers developed for DHN transcripts in a closely related species, Picea abies (L.) Karsten, and isolated and sequenced PCR products for five P. obovata DHNs. Three protein bands of 53, 35 and 33 kDa were detected on western blots of SDS–PAGE-separated protein extracts. The 53-kDa DHN was already present late in the growing season, but accumulated during acclimation, and levels decreased rapidly during deacclimation. The 33- and 35-kDa proteins, identified as Picg5 class DHNs by mass spectrometry, first appeared in detectable amounts late in the acclimation process and remained at detectable levels throughout the period of maximum LT tolerance. Levels of the 53-kDa DHN correlated with two LT tolerance parameters, while results for the 33- and 35-kDa proteins were equivocal due to limited sample size and variation in LT tolerance during the mid-winter period. Three additional bands of 30, 28 and 26 kDa were detected in extracts from needles collected in November 2010 using an immunity-purified antibody. Immunoblotting of two-dimensional gel electrophoresis gels loaded with proteins extracted from October and November samples corroborated the results obtained by SDS–PAGE western blots. One large spot in the 53 kDa range and two trains of spots in the same size range as the 33 and 35 kDa DHNs were detected using the K-segment antibody. Eight of the nine DHN transcripts closely tracked LT tolerance parameters, whereas the ninth DHN transcripts followed a reverse pattern, decreasing during winter and increasing again during deacclimation. Multiple regression models using principal components of the transcripts to predict two different LT tolerance parameters suggest separate but overlapping functions for different DHNs in establishing and maintaining extreme LT tolerance.
Forfattere
Atle HaugeSammendrag
Nedbørmengde og nedbørintensitet er forhold som må vektlegges ved dimensjonering av sugegrøfter og særlig samlegrøfter. Avrenningskoeffisienten velger en ut fra behovet for rask senkning av grunnvassspeilet, nedbørmengdene og nedbørintensitet i området og jorda si vannledningsevne.
Sammendrag
Tap av nitrogen med grøfte- og overflatevatn frå eng er særleg påverka av nedbørsmengde, tidspunkt for spreiing av gjødsel, jordart, kor sterkt det er gjødsla og driftsmåte elles. Kva gjødselslag som er nytta, hysdyrgjødsel eller handelsgjødsel, synest i mindre grad å verka inn.
Forfattere
Liv Østrem Samson ØpstadSammendrag
Med auka fokus på grovfôrkvalitet og ein lengre vekstsesong, er ei godt drenert jord viktig for at bonden raskast råd kan koma ut på jordet, både om våren for jordarbeiding og gjødsling og for å hausta i vekstsesongen.
Forfattere
Ivar HovlandSammendrag
Lønnsomheten ved grøfting bør vurderes ut fra et helhetssyn der kostnadene måles mot høyere avling, bedre driftsmessige forhold og økt fleksibilitet i bruken av jorda. Anleggets forventede levetid og rentenivå betyr også mye for lønnsomheten ved grøfting.
Forfattere
Jarle Werner Bjerke Stef Bokhorst Terry V. Callaghan Matthias Zielke Gareth K. PhoenixSammendrag
Background: Arctic lichens and mosses are covered by snow for more than half the year and are generally considered as being dormant for most of this period. However, enhanced frequency of winter warming events due to climate change can cause increased disturbance of their protective subnivean environment. Aim: To further understand cryptogamic responses to mid-winter warming we compared the ecophysiological performance of one lichen and one moss species during a simulated warming event. Methods: We measured photosynthesis and dark respiration in samples of the moss Hylocomium splendens and the lichen Peltigera aphthosa removed from under snow, and on natural refreezing after the warming event, which was simulated by using infrared heaters suspended above the ground. Results: The moss exposed to light at +5 °C immediately after removal from their subnivean environment and from warmed plots showed positive net gas exchange within 332 s; the lichen required 1238 s. Photosynthesis and nitrogen fixation rates were equal to that, or higher than, during the preceding growing season. Upon refreezing after the event, moss photosynthesis declined considerably. Conclusions: The moss, and to a lesser extent the lichen, may contribute to subnivean midwinter ecosystem respiration, and both are opportunistic, and can take advantage of warmer winter phases for photosynthesis and growth. This ought to be taken into account in vegetation change projections of cryptogam-rich ecosystems. carbon flux; climate change; cryptogams; dormancy; gas exchange; nitrogen fixation; reactivation; snow melt; subnivean environment; winter warming
Forfattere
William White Anders Lunnan Erlend Nybakk Biljana KulisicSammendrag
The renewable energy sector (RES) often receives financial, institutional or educational support from the government. A significant challenge for the actors in the RES field is policy consistency. When investments are carried out, a prognosis for future policies must be made. If the future is uncertain, larger risk margins should be included in the investment appraisals. Sudden, unexpected policy changes are one type of uncertainty that makes it more difficult to attract capital. In this article, we discuss the consequences of discontinuities in policy support using a case study approach. In Ontario, feed-in tariffs were introduced in 2009 and resulted in a large uptake in the programme. In 2010, the subsidies were drastically cut, resulting in the RES community losing confidence that the government would offer consistent support to the sector. In Norway, a large new biodiesel plant was opened by the Minister of the Environment only a few weeks before the government announced a major change in the bioenergy policy. As a result, the new plant was closed and restructured, and the investors lost nearly all of their investments. The government lost political credibility, making it difficult to raise private capital for new investments in this sector in Norway. We do not argue that policies should not be changed, but the manner in which policies are changed plays an important role. Our study shows that large, unexpected changes in policies increase uncertainty and may have a negative impact on investments. This topic should be further researched.