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.
2012
Sammendrag
Groundwater pollution by agrochemicals, degradation of soil quality and pollution of aquatic ecosystems by agricultural drainage waters have become an issue in the last decades. Flow processes in the vadose zone are closely related to these problems. In general, water flow in soils can be classified into two major categories: uniform and non-uniform (preferential) flow (In: U.S. National Committee for Rock Mechanics, Conceptual Models of Flow and Transport in the Fractured Vadose Zone, 2001, pp.149-187). The former describes a relatively slow movement of water through the porous soil matrix and can be modelled by Richard”s equation. The latter comprises all flow types where water bypasses a portion of the soil matrix and flows through localised (i.e. preferential) paths. Unlike uniform flow, preferential flow is hardly predictable because the assumptions of Richard”s equation of a homogeneous representative elementary volume characterised by a single value of water potential, water content and hydraulic conductivity are frequently violated (Eur J Soil Sci, 2007; 58:523-546)....
Sammendrag
From the range of information published, acetylation appears well suited to provide adequate protection against biological attack for materials derived from typically non-durable wood species. Acetylated wood is now commercially available both in Europe and in the USA. But still there are a lot of unanswered questions related to fungal decay mechanisms in acetylated wood.The paper summarize existing knowledge and highlight future research opportunities related to fungal deterioration of acetic anhydride modified wood. In addition statistical analyses based on previously published data were performed to quantify what factors contribute most to the performance (calculated as test sample/control).The results showed that WPG can explain approximately 50 % of the performance, measured as test sample/control (T/C), for acetic anhydride treated wood. Other of the applied variables, like wood species or type of fungus can reduce the variance in T/C by additional 15 %.
Forfattere
Halvor SolheimSammendrag
Furuas knopp- og grentørkesopp er en av furuskogens verste skadegjørere, og forårsaker år om annet store tap. Det største angrepet skjedde i 2001, da enorme områder i Sør-Norge og Sør-Sverige ble berørt. Milde høster og ustabile vintre kan føre til flere slike angrep.
Sammendrag
I en 5-årsperiode har Landsskogtakseringen registrert beitetrykk og beitetilbud på 11 000 prøveflater innenfor store deler av elgens utbredelsesområde i Norge. Resultatene viser at elgen i nord kan velge fra øverste hylle, både sommer og vinter, mens elgen i sør må dele på godene. I Troms er det fire ganger flere beitetrær tilgjengelig pr elg enn hva som er tilfelle i Agder, og en langt større andel består av de mest selekterte artene. I tillegg er arealet av attraktive feltsjiktplanter 50 ganger større pr elg i nord enn i sør.
Sammendrag
Gjengroing med skog pågår i mange deler av landet, og dette vil påvirke mange freda bygninger og kulturmiljøer. Spesielt utsatt er freda bygninger knyttet til land- og fiskebruk. Av de 2774 freda bygningene som kan knyttes til land- og fiskebruk, ligger 1560 (56%) i områder som gror igjen. Direkte kan gjengroing med skog øke bygningenes fysisk nedbryting blant annet gjennom fuktigere luft rundt bygningene (tiltakende forråtnelse), gjengrodde dreneringer og rotsprengning på grunnmurer. I alt vil gjengroinga stille økende krav til vedlikehold, og framtidige klimaendringer kan forsterke konsekvensene betydelig.
Forfattere
Kjersti Holt HanssenSammendrag
Selective cutting and other continuous cover forestry systems may be used in spruce forests where for instance environmental or recreational considerations are more important than forest production. However, in order for this system to be sustainable, successful regeneration must be achieved. The supply of both light and below-ground resources may influence the growth and development of seedlings. If a diverse tree species composition is desirable, knowledge of the gap sizes necessary to sustain seedling survival and growth of different species is important. We studied the growth of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) seedlings in the understory, using two Norway spruce sites with selective cutting and group fellings in SE Norway. 4-week old seedlings (henceforth: mini seedlings) were planted in plots with and without trenching in gaps of four different sizes, ranging from 20 to 500 m2. In addition, commercial seedlings of the two species were planted pairwise across the sites. After three years the mini seedlings were dug up and measured, while the survival and growth of the commercial seedlings were followed for eight years. Differences in seedling survival and growth characteristics due to gap size and (for mini seedlings) trenching were analysed using GLM. Mortality was high, especially for pine seedlings. This was due to grazing as well as competition for light and nutrients. Growth of both species was positively correlated with increasing gap size. This applied for height, diameter, shoot volume and needle biomass as well as total dry weight for both spruce and pine seedlings. However, trenching had a significant positive effect on growth too, also in the smallest gaps.
Forfattere
Kjell Andreassen Bernt-Håvard ØyenSammendrag
Growth conditions in Fennoscandia are characterized by relatively short growth seasons and cold winters, from 130 growth days (T 5C) in the far north high mountains to more than 200 in south Sweden and Norway. Growth models from different regions predict different forest growth.In this study, we compare some models commonly applied in forest growth prognosis in pure even aged stands of Norway spruce, Scots pine and birch in Finland, Sweden and Norway. The objectives is to identify behavioural properties, accuracy and bias in selected Nordic growth models using a wide-ranging test data set from permanent research plots in Norway.Present tentative conclusions about the accuracy of growth outside the geographical range of the original base materials. With four different response variables in the tested models we emphasized relative deviations rather than absolute values as most suitable for comparisons. The models were compared by statistical tests, a visual inspection of the smoothed curve of the relative deviations in different stand properties and ranked due to their performance.We observed site index, stand density and mean tree size as the three main components in the models. For Norway spruce a basal area increment model from Sweden had the lowest standard deviation with 23 %. The mean R2 between residuals and stand characteristics from this model was also low (1.3 %), which indicates that variables are well included in the model. For Scots pine and birch, Finnish percent volume growth models showed the best fit to the Norwegian test data, with a R2 between residuals and stand characteristics of 2.8 and 6.7 %, respectively. Several of the models from Sweden and Finland predict the growth as well as stand models frequently in use in Norway.
Sammendrag
Grantrær og barkbiller har slåss i millioner av år. Kunnskap om granas forsvar kan gjøre det mulig å redusere barkbilleskader gjennom planteforedling og skogskjøtsel. Ny forskning viser at grantrær kan unngå å bli drept av barkbiller hvis de er raske til å produsere mye kvae.
Forfattere
Erlend NybakkSammendrag
Growing attention is being paid to innovation and creativity and learning as success factors for sustainable competitive advantage and financial performance. This paper examines the relationships between innovation strategy, innovative working climate, learning orientation and financial performance in the context of the Norwegian wood industry. A questionnaire-based survey was sent to CEOs of firms in the wood industry in Norway (241 usable replies, response rate of 49 percent). Innovation strategy embodies four dimensions: the degrees to which innovation in the form of products, processes, and business systems are embedded in the management values and priorities as well as the degree of expenditure in R&D. An innovative working climate is exemplified by team cohesion, supervisory encouragement, resources, autonomy, challenge, and openness to innovation. Both learning orientation and firm innovativeness were conceptualised and analysed as latent second-order constructs using structural equation modelling. The result implied that innovation strategy and an innovative working climate enhanced financial performance in Norwegian wood industry. Furthermore, the findings showed that learning orientation had a positive affect on financial performance positively via firm innovativeness (full mediating effect). Findings suggest that managers in wood industry will not likely benefit financially from a learning orientation without also achieving high levels of firm innovativeness. Moreover, findings suggest that managers should focus on creating an innovative working climate and prioritising an innovation strategy.
Sammendrag
In South-east Norway, several scattered observations of reduced growth and dieback symptoms were observed over the last 20 years in 40-60 years old Norway spruce (Picea abies) trees. Typical symptoms start with yellowing in the top and subsequent dieback downwards from the top. These symptoms are often combined with bark beetle (Ips typographus), honey fungus (Armillaria spp.) infections, and a sudden decrease in diameter and height growth. After about 1-5 years, most of the symptomatic trees are dead.We selected 11 representative stands in six counties. In each stand all trees in ten 250 m2 plots were evaluated, in total about 4000 trees. In each of these 110 plots, one symptomatic and one non-symptomatic tree were investigated in more detail. We measured tree diameter, height, took increment cores and assessed crown condition, wounds, resin flow, stem cracks, bark beetle infection and Armillaria presence. In addition, internode lengths of the last 20 years were measured in two of the stands.Preliminary results of internode lengths and increment cores showed a sudden decrease of height and diameter growth in the symptomatic trees. Many of these trees had a secondary infection of bark beetles and Armillaria. Some years appear to be typical problem years for many of the trees. These years also correspond with summer drought, i.e. negative Palmer drought severity indexes which were estimated for each stand. In comparison, the non-symptomatic trees, growing close to the symptomatic ones, showed none or minor growth reductions and discolouration.Climate change and increased summer drought may worsen spruce dieback problems. Management adaptions are uncertain. We conclude that Norway spruce is sensitive to drought, which reduce the growth and weaken the health, and probably reduce the defence against secondary infections.