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
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.
Forfattere
Kjell Andreassen Volkmar Timmermann Nicholas Clarke Erik Framstad Per Arild Aarrestad Vegar Bakkestuen Tonje Økland Jørn-Frode Nordbakken Ingvald Røsberg Inga E. Bruteig Marianne Evju John Atle Kålås Torgeir NygårdSammendrag
The report presents results for 2011 from three national monitoring programmes on long-range transboundary air pollution.
Forfattere
Nicholas ClarkeSammendrag
This report aims to summarise briefly the findings in the scientific literature concerning the effect of both stem-only and whole-tree harvesting on soil carbon stocks. Although the findings reported by previous authors vary, it is possible to draw some general conclusions about the effect of harvesting on soil carbon, and on whether whole-tree harvesting has a greater effect than stem-only harvesting. In general it appears that the organic C content in the soil’s organic layer is reduced after stem-only harvesting, sometimes by as much as 50%. This reduction has been explained in several ways. After a period of maybe 20 years, the carbon content of the organic layer starts to increase again. In the mineral soil a reduction is not always apparent and the C content can even increase, probably because of the incorporation of residues into the soil. Some studies have shown that this increase is short-lived, while others have found a longer-term increase. Unsurprisingly, thinning appears to affect the soil carbon content much less than clear-cutting; the effect tends to be proportional to the thinning intensity. The soil carbon content appears to be higher after selection cutting than after clear-cutting. Studies comparing effects of whole-tree harvest with those of stem-only harvest have tended to show smaller carbon contents in the mineral soil after whole-tree harvest than after stem-only harvest, although once again results vary greatly. There are many factors affecting soil C content and thus accounting for the observed differences, including temperature, moisture content, and harvesting type. Variation in the results obtained may depend on site-specific factors such as site nutrient status, especially with regard to the most common limiting nutrient nitrogen, which will affect growth in the next rotation. Making sure there are enough nutrients available, if necessary by compensatory fertilisation, will improve carbon sequestration in both trees and soil.