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.
2011
Sammendrag
I denne rapporten presenteres resultatene fra resultatkontrollen i 2010, som omfatter foryngelseskontroll, kontroll av skogsveger og kontroll av skogbruksplaner. Foryngelseskontrollen er fra og med 2010 noe endret i forhold til tidligere praksis, ved at den nå gjennomføres på felter som ble avvirket tre år tidligere, mens kontrollobjektene tidligere ble valgt ut blant hogster gjennomført to år før kontrollåret. Dette medfører at det i både årets og fjorårets kontroll er valgt ut felter som ble avvirket i løpet av 2007. Resultatene fra årets foryngelseskontroll er basert på 941 kontrollerte foryngelsesfelt.
Sammendrag
Vegetation height information is one of the most important variables for predicting forest attributes such as timber volume and biomass. Although airborne laser scanning (ALS) data are operationally used in forest planning inventories in Norway, a regularly repeated acquisition of ALS data for large regions has yet to be realized. Therefore, several research groups analyze the use of other data sources to retrieve vegetation height information. One very promising approach is the photogrammetric derivation of vegetation heights from overlapping digital aerial images. Aerial images are acquired over almost all European countries on a regular basis making image data readily available. The Norwegian Forest and Landscape Institute (Skog og Landskap) invited researchers and practitioners that produce and utilize photogrammetric data to share their experiences. More than 30 participants followed the invitation and contributed to a successful event with interesting presentations and discussions. We wish to thank the speakers for their contributions and hope that all participants found the seminar useful. These short proceedings of the seminar include summaries of the talks. The presentations, which provide more information, can be found at the end of this document.
Sammendrag
The Norwegian National Forest Inventory (NNFI) provides estimates of forest parameters on national and regional scales by means of a systematic network of permanent sample plots. One of the biggest challenges for the NNFI is the interest in forest attribute information for small subpopulations such as municipalities or protected areas. Frequently, too few sampled observations are available for those small areas to allow an estimate with acceptable precision. However, if an auxiliary variable exists that is correlated with the variable of interest, small area estimation (SAE) techniques may provide means to improve the precision of estimates.
Sammendrag
Top dieback and mortality of Norway spruce is a particular forest damage that has severe occurrences in scattered forest stands in southeast Norway. As a part of a project to study the extent and causes of the damage we are working on an algorithm for automatic detection dead and declining spruce trees for an entire county, - Vestfold. The data set is aerial imagery. The county was covered in 2007. Preliminary tests showed a considerable confusion between dead trees and bare ground. In order to avoid this confusion we have had the imagery automatically processed into a photogrammetric digital surface model (DSM) and true orthophotos. The data set derived from this processing was a 5 layer file, containing blue, green, red, and near-infrared, as well as the height above ground of the canopy height model (a DSM normalized by the terrain height, nDSM)
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
This study is a part of a larger project designed to find out the causes of top dieback symptoms in Norway spruce in SE Norway. Because sapwood tracheids constitute a water transport system while parenchyma serves as a reserve tissue (Sellin, 1991), the separation and quantification of the sapwood and heartwood may contribute to understanding of the healthy tree functioning. As the extent of sapwood is related to tree vitality, it reflects the tree growth, health and effect of environmental factors (Sandberg & Sterley, 2009). Therefore, the sapwood cross-sectional area is widely used as a biometric parameter indicating the tree vitality, although its estimation and evaluation is prone to scaling errors....
Forfattere
Knut Ole VikenSammendrag
Det ble utført en kontrolltakst av Landsskogtakseringens permanente prøveflater på Vestlandet, Trøndelag og Nordland sør for Saltfjellet i 2009. Til sammen 60 flater fordelt på 8 lagledere ble oppsøkt av en kontrollør, og samsvar og avvik for ulike parametere er vurdert. Avvik mellom lagledere og kontrollør varierer mellom de ulike parameterne. Resultatene viser at det for de fleste parametere er meget bra overensstemmelse mellom lagledere og kontrollør. Registreringene med størst avvik er elgbeite og blåbærdekningsprosent. Bestandsalder i lauvskog og kronedekningsprosent viser god overensstemmelse for mange flater, men det finnes enkelte flater med relativt store avvik. Tremålingene er generelt bra, men resultatene viser at enkelte nye innvokste trær blir uteglemt ved klavingen for flere lagledere.
Forfattere
Ishita Ahuja Birgit Hafeld Borgen Magnor Kåre Hansen Bjørn Ivar Honne Caroline Müller Jens Rohloff John Trevor Rossiter Atle M. BonesSammendrag
Det er ikke registrert sammendrag
Sammendrag
Ungskogpleie anses å være blant de viktigste behandlingsmessige tiltak man kan gjennomføre i skogen og med solid tradisjon i nordisk skogbruk. I denne artikkelen ser vi litt nærmere på hvordan ungskogpleie bidrar til å påvirke skogens langsiktige utvikling. Skogforskningen har siden 1950-tallet drevet systematiske undersøkelser på effektene av ungskogpleie.
Forfattere
Eirik NordhagenSammendrag
We studied drying of wood chips by surplus heat from two hydroelectric plants in the western part of Norway. The wood was chipped and loaded into the dryer; a tractor-trailer and a container were used. The dryers had perforated floors where warm air from the plants was funnelled into the dryer, using an electric fan of 4 kW. Four separate trials were conducted in September and October 2009. The drying capacity of the trailer and the container was roughly 11.5 m3 and 29 m3 loose respectively. The effective height at which drying took place was 1.2 m and 1.9 m. The average temperatures of the air channelled into the dryers was 15–18 °C in the trailer and 24–26 °C in the container. The fan was operated for 139 hours (twice) for the trailer and 121.5 and 67.5 hour periods for the container. The fan used 556 kWh (twice), 486 kWh and 270 kWh of electricity respectively. The chips located at the bottom dried first, and chips located above dried later. The water content in the chip was measured to 66.1 to 52.1% (wet base) before and 9.6 to 6.9% (wet base) after drying. The amount of water removed from the container was approximately 28 kg per hour and 22 kg per hour from the trailer. For the container, drying cost roughly 9 Euro per MWh; the cost of the trailer was nearly twice as much. This indicates that the drying volume should be as high as possible. Drying determines net calorific value and hence market value of wood chip.