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
Det er ikke registrert sammendrag
2011
Forfattere
Helmer BelboSammendrag
The theoretical potential for increased efficiency in early thinning by using accumulating harvester heads was investigated through simulation. Thinning was performed in corridors perpendicular to the strip road in 75 artificially generated stands with varying average tree size and density. The work pattern and work time in the crane work for five sizes of heads, with grapple diameters in the range of 10 to 50 cm, was estimated by the simulation model. The efficiency increased rapidly when the grapple diameter increased from two to four times the average diameter in the harvested stand, reducing the work time per tree by 15 to 50 percent compared to the single tree handling harvester head. Further increases in grapple dimension also increased the efficiency, but not at the same rate. In real work, the efficiency increase by an accumulating harvester head will probably be slightly lower due to less optimal harvesting conditions, operator skills and other non-productive work tasks that are not affected by work method.
Forfattere
Helmer BelboSammendrag
I denne rapporten gis en oversikt over tidsforbruk og kostnader i forbindelse med innsamling og bruk av halm som biobrensel i småskala fyringsanlegg. Rapporten er basert på data fra sju gårdbrukere med egne halmfyringsanlegg som i tre år har rapportert tidsforbruk og kostnader i sin halmforsyning. Seks av brukerne benyttet rundballer og sats-fyrte anlegg, mens en benyttet store firkantballer og anlegg med kontinuerlig innmating.....
Forfattere
Robin Engler Christophe E. Randin Wilfred Thuiller Stefan Dullinger Niklaus E Zimmermann Miguel B. Araujo Peter B. Pearman Gwenaëlle Le Lay Christian Piedallu Cécile H. Albert Philippe Choler Georghe Coldea Xavier De Lamo Thomas Dirnböck Jean-Claude Gegout Daniel Gómez-García John-Arvid Grytnes Einar Heegaard Fride Høistad Schei David Nogues-Bravo Signe Normand Mihai Puscas Maria Teresa Sebastia Angela Stanisci Jean-Philippe Theurillat Mandar R. Trivedi Pascal Vittoz Antoine GuisanSammendrag
Continental-scale assessments of 21st century global impacts of climate change on biodiversity have forecasted range contractions for many species. These coarse resolution studies are, however, of limited relevance for projecting risks to biodiversity in mountain systems, where pronounced microclimatic variation could allow species to persist locally, and are ill-suited for assessment of species-specific threat in particular regions. Here, we assess the impacts of climate change on 2632 plant species across all major European mountain ranges, using high-resolution (ca. 100 m) species samples and data expressing four future climate scenarios. Projected habitat loss is greater for species distributed at higher elevations; depending on the climate scenario, we find 36–55% of alpine species, 31–51% of subalpine species and 19–46% of montane species lose more than 80% of their suitable habitat by 2070–2100. While our high-resolution analyses consistently indicate marked levels of threat to cold-adapted mountain florae across Europe, they also reveal unequal distribution of this threat across the various mountain ranges. Impacts on florae from regions projected to undergo increased warming accompanied by decreased precipitation, such as the Pyrenees and the Eastern Austrian Alps, will likely be greater than on florae in regions where the increase in temperature is less pronounced and rainfall increases concomitantly, such as in the Norwegian Scandes and the Scottish Highlands. This suggests that change in precipitation, not only warming, plays an important role in determining the potential impacts of climate change on vegetation.
Forfattere
Fride Høistad ScheiSammendrag
Det er ikke registrert sammendrag
Sammendrag
Wood as a hygroscopic material gains or loses moisture with changes in climate of the surrounding air. The moisture content influences strength properties, hardness, durability and machinability. Therefore the hygroscopicity is a very important property, last but not least for economic factors. Below fibre saturation, a change in moisture content causes shrinkage or swelling and anisotropic behaviour can be seen in the different growth directions. For a better understanding of the sorption behaviour of Scots pine (Pinus sylvestris L.) the variation between different adsorption and desorption curves has been investigated. Trees from 25 different sites in Northern Europe were collected and 3651 samples (1510 heartwood- and 2141 sapwood-samples) measuring 5 (T) x 10 (R) x 30 (L) mm were obtained. The sorption isotherms for all specimens were measured at 25 °C at relative humidities of 15, 35, 55, 75 and 95 % for both desorption and adsorption. The aim of this study is to investigate the influence of raw material variability on the sorption behaviour of Scots pine. Due to the different growing conditions, densities and wooden material (heart or sapwood) variations within the sample groups have been found. Correlations between moisture and density respectively latitude were investigated.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Kjell Andreassen Bernt-Håvard ØyenSammendrag
Fourteen Nordic increment functions have been validated by use of with a test data set from long-term research plots in Norway of even-aged, pure stands of Scots pine, Birch and Norway spruce. In selected functions from Denmark, Finland, Norway and Sweden measures of site productivity, mean tree size and various stand characteristics are represented. Different models display both strengths and weaknesses in their predicting ability. Some measures of precision and bias have been calculated and the functions are ranked due to their performance. Basal area increment models for spruce and pine from Sweden, and a Finish volume increment model for birch has the best fit to the Norwegian test data. Some of the growth models developed outside Norway estimate the growth with about the same accuracy as the models frequently used and developed in Norway. The results indicate that forest conditions and traditional even-aged forest management practice in the Nordic countries seem to have small influence on the relative growth of even-aged stands. By careful recalibration of existing functions from other Nordic countries with data from Norway, a reasonable accuracy could be achieved in Norwegian forest with a reduction of the bias.
Forfattere
Vibeke Stærkebye Nørstebø Ulf Johansen Hanne Marie Gabriel Bruce Talbot Jan-Erik Ørnelund NilsenSammendrag
Hovedmålet med prosjektet er å utarbeide en prioritert investeringsplan for utbygging av tømmerkaier langs norskekysten, slik at forholdene legges til rette for en rasjonell tømmertransport fra skog til industri. Vi har benyttet matematisk programmering til å identifisere det optimale antall, størrelse og lokalisering av tømmerkaier - i dag og over en tidshorisont på 20 år. Modellen er tilpasset slik at den tar hensyn til dagens og fremtidens avvirkningsvolum, infrastruktur, kostnader og tariffer, og for øvrig andre målbare faktorer som påvirker samlede transportkostnader. Ved hjelp av modellen har vi identifisert en skissemessig plan for lokalisering, dimensjonering, og utbygging av tømmerkaier langs norskekysten, samt en følsomhetsanalyse for viktige drivere. Den viser at investeringskostnad for kaier, kundenes lokalisering og tilhørende etterspørsel, og kostnad for lastebiltransporten og endret veikvalitet / bruksklasse (foruten totalt avvirkningsvolum) har størst effekt på resultatet og totalkostnaden. Prosjektet har også vurdert andre miljø- og samfunnsgevinster av en slik utbygging langs kysten. Flere kaier (for samme mengde avvirket tømmer), og tilhørende redusert antall kilometer tømmertransport med lastebil ser ut til å være gunstig med tanke på miljøutslipp. Det er også potensial for å utvikle modellen til å analysere flere ting enn hva som ligger inne per i dag. Et aspekt som bør inkluderes er profittmaksimering (overskudd) og verdikjedeoptimering.