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.
2006
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Frode VeggelandSammendrag
Det er ikke registrert sammendrag
Forfattere
Anne Sverdrup-Thygeson Tor Erik Brandrud Harald Bratli Jan-Erik Ørnelund Nilsen Jogeir N. Stokland Frode ØdegaardSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Terje BirkelandSammendrag
Etterspørselen etter ferdige brukervennlige trelastlengder øker. Ved å tilpasse lengdene allerede i skogen vil råstoffutnyttelsen øke. Lønnsomheten ved aptering av gran i faste lengder er derfor sammenligna med tradisjonell aptering i to forsøk. Faste lengder ga 1,2 % høgere lønnsomhet enn tradisjonell aptering (prima/sekunda) på grovt, pent tømmer, først og fremst pga. høgere sentrumsutbytte og stammeutnyttelse, samt lite svekka trelastkvalitet ved faste lengder. På normaltømmeret (mindre dim, lågere kvalitet) regna vi med lågere trelastkvalitet og lønnsomhet for faste lengder. Resultatet blei derimot at trelastkvaliteten ikke blei negativt påvirka av faste lengder. Samtidig ga faste lengder langt bedre stammeutnyttelse enn prima/sekunda volummessig, og produserte dessuten verdifull trelast også av et betydelig volum som forsvant til massevirke ved tradisjonell aptering. På normaltømmeret ga faste lengder 12,2 % høgere lønnsomhet enn prima/sekunda.
Tidsskriftspublikasjon – Klingende graner - om klangtre og felemakere
Peder Gjerdrum, Mauro Bernabei
Forfattere
Peder Gjerdrum Mauro BernabeiSammendrag
Utvalgte trakter i de østlige Alper er velkjent for sitt klangtre. Denne spesielle kvaliteten av vanlig gran (Picea abies) har vært kjent og benyttet i området gjennom århundrer. Den symbolske verdien overgår trolig den økonomiske. Også norske felemakere har lært seg til å finne frem til de beste forekomstene i våre skoger. Det endelige utvalget har alltid et islett av kunst – og kanskje litt hemmelighetskremmeri, mystikk. Likevel gis det noen generelle ytre kjennetegn. I Dolomittene fins de beste forekomster i nordvendte lier og midlere høydelag. Trærne må vise jevne årringer, være rettvokste og feilfrie. Etter omsorgsfull pleie i et århundre eller mer avvirkes trærne utenom vekstsesongen og oppdeles i passende stykker alt etter senere anvendelse, f.eks. til fele eller til piano. Treet tørkes på et luftig sted beskyttet mot vær og vind, før felemakeren bestemmer hvilke stykker han vi ha og hvilke som forkastes.
Forfattere
Kjersti Holt HanssenSammendrag
An increasing interest for uneven-aged forestry requires more knowledge concerning the impact of selective cuttings on the physical environment, and the effect of an uneven-aged forest structure on establishment and growth of the regeneration. Our objectives were to correlate pre-harvest growth and vitality of advance seedlings and saplings with light levels in the stands, and to measure the change in light availability following selective cuttings. We performed a selective cutting with two levels of removal (40 and 60 % of standing volume) in three uneven-aged stands in eastern Norway, two Norway spruce (Picea abies) stands and one Scots pine (Pinus sylvestris) stand. The standing volumes in the spruce stands were approximately 300 m3 ha-1, in the pine stand 180 m3 ha-1. The selective cutting was aimed at removing the economically ripe trees, resulting in the removal of large as well as damaged and diseased trees. Light levels were measured with hemispherical photography before and after cutting, and sapling growth and vitality was registered. Spruce sapling vitality and growth before cutting varied with light conditions. Saplings with good vitality on average received 26 % of full daylight. Few pine saplings had good vitality even though the average light level in the pine stand was 35 %, illustrating the difference in shade tolerance between the two species. The relationship between light levels and sapling growth might be caused by the availability of both light and soil resources, as a large gap will offer a better supply of nutrients and water as well as light. The selective cutting increased average light levels with 10-30 percent points. In the spruce forests, the frequency distribution curve of measured light values was rather narrow and peaked before harvesting but wide and low afterwards (Fig. 1), indicating that the selective cutting created a broad range of site conditions below the canopy. For the pine forest, the light distribution curve kept a rather narrow, unimodal shape also after cutting.
Forfattere
Per Otto Flæte Erlend Ystrøm Haartveit Kjell VadlaSammendrag
Considerable areas in the northern parts of Norway are afforested with Picea abies (L.) H.Karst. (Norway spruce), Picea × lutzii Little (Lutz spruce), and Picea sitchensis (Bong.) Carrière (Sitka spruce). The species have different machining and wood properties but are similar in visual appearance. We evaluated whether near infrared (NIR) spectroscopy combined with multivariate statistical modelling could be used to identify wood from these three species. In all, 83 wood specimens were available for analyses, 36 of which were used as a test set for model validation. NIR spectra were obtained on the cross-sectional surfaces. An initial principal component analysis showed that little information from the first and second components could be used for discrimination, but in score-plots of the third and fourth components the samples from the tree species formed clusters. This showed that the NIR spectra did contain information relevant for tree species identification, and that only a small fraction of the total variance could be used for that purpose. For classification of the wood specimens, partial least squares discriminant analyses were applied. All 47 specimens in the training set were fitted into the correct group. The test set validated results showed that except for two wood specimens, all specimens were correctly classified. The two misclassified samples were Sitka spruce. This study showed that development of well-performing rediction models for differentiation of wood from Norway spruce, Lutz spruce, and Sitka spruce is possible.
Forfattere
Gilbert Kamgan Nkuekam Jolanda Roux Halvor Solheim Michael J. WingfieldSammendrag
Det er ikke registrert sammendrag
Sammendrag
A method for quantitative determination of extractives from heartwood of Scots pine (Pinus sylvestris L.) using gas chromatography (GC) with flame ionization detection (FID) was developed. The limit of detection (LOD) was 0.03mg/g wood and the linear range (r=0.9994) was up to 10mg/g with accuracy within ±10% and precision of 18% relative standard deviation. The identification of the extractives was performed using gas chromatography combined with mass spectrometry (GC–MS). The yields of extraction by Soxhlet were tested for solid wood, small particles and fine powder. Small particles were chosen for further analysis. This treatment gave good yields of the most important extractives: pinosylvin, pinosylvin monomethyl ether, resin acids and free fatty acids. The method is used to demonstrate the variation of these extractives across stems and differences in north–south direction.