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
The paper analyses and discusses possible impacts on Norwegian agriculture of an EU membership based on the regionalized agricultural sector model CAPRI. Norwegian agriculture is characterized by a small-scale farming structure and high levels of support. Previous analyses have shown that Norwegian agriculture is expected to undergo dramatic changes because of EU membership in terms of farm income, production and structural change. Our study indicates that a substantial share of the agricultural production can be maintained at the national level. Milk and crop production may remain largely unaffected, while meat production decreases in the range of 10–20% compared to a reference run without membership. However, a reduction in total farm income by about 40% indicates that structural adjustments will follow EU accession. The results are discussed in view of the pattern of adjustments observed in Finland and Austria after EU accession in 1995. The need for the dairy industry to take advantage of the improved market access is stressed. Attention is also called to some strengths and limitations of the CAPRI model to analyse large-scale policy changes and to identify model improvements as an area of future research.
Forfattere
Øyvind HansenSammendrag
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Forfattere
Arild SpissøySammendrag
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Forfattere
Ola Wågbø Oddmund HjukseSammendrag
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Forfattere
Heleen A. de Wit Taru Palosuo Gro Hylen Jari LiskiSammendrag
Growing stocks of trees in Europe have increased in a magnitude that is significant in terms of carbon (C) sink strength. Estimates of the soil C sink strength that this increased stock of trees may have induced on a regional scale are scarce, uncertain and difficult to compare. This illustrates the need for a widely applicable calculation method. Here, we calculate a C budget of productive forest in southeast Norway based on forest inventory information, biomass expansion factors (BEF), biomass turnover rates and the dynamic soil model Yasso. We estimate a 29% increase (112-145 Tg) of C in biomass between 1971 and 2000, and estimate the associated increase of C in soils (including dead wood) to be 4.5% (181-189 Tg). The C sink strengths in biomass and soils (including dead wood) in 1990 are 0.38 and 0.08 Mg ha(-1) yr(-1), respectively. Estimated soil C density is 58 Mg C ha(-1) or ca 40% of measured soil C density in Norwegian forest soils. A sensitivity analysis - using uncertainty estimates of model inputs and parameters based on empirical data - shows that the underestimation of the soil C stock can be due to overestimation of decomposition rates of recalcitrant organic matter in the soil model and to including only trees as a source of litter. However, uncertainty in these two factors is shown to have a minimal effect on soil sink estimates. The key uncertainty in the soil sink is the initial value of the soil C stock, i.e. the assumed steady state soil C stock at the start of the time series in 1970. However, this source of uncertainty is reduced in importance for when approaching the end of the data series. This indicates that a longer time series of forest inventory data will decrease the uncertainty in the soil sink estimate due to initialisation of the soil C stock. Other, less significant, sources of uncertainty in estimates of soil stock and sink are BEF for fine roots and turnover rates of fine roots and foliage. The used method for calculation of a forest C budget can be readily applied to other regions for which similar forest resource data are available.
Sammendrag
Alternative metoder for å begrense skader forårsaket av gransnutebillen er svært aktuelle, både av hensyn til miljøet og fordi dagens kjemiske midler er på vei ut av bruk. I denne artikkelen fokusere vi på muligheten for å bruke et biologisk middel, nyttenematoder. Strategien med bruk av nyttenematoder går ut på å redusere produksjonen av nye gransnutebiller ved å drepe så mange larver som mulig i stubbene hvor de lever.
Forfattere
Kjell VadlaSammendrag
Hensikten med arbeidet var å fremskaffe representative tall for basisegenskaper hos bartrevirke fra natur- og kulturskog. Denne rapporten omhandler anatomiske- (bark, kjerneved), fysiske- (basisdensitet, rådensitet) og geometriske egenskaper (avsmaling, flattrykking). Resultatene fra de andre egenskapsundersøkelsene publiseres ved NTI (tekniske-/mekaniske egenskaper, fysiske egenskaper) og PFI (fiberegenskaper, andre anatomiske egenskaper). Materialet i denne undersøkelsen besto av i alt 132 gran- og 60 furutrær fra forskjellige geografiske områder på Øst- og Sørlandet. Når det gjelder gran, strakk området seg fra Vestfold/Telemark i sør til Stange/Romedal i nord, for furu fra Evje/Hornnes i sør til nord i Østerdalen (Rendalen). Både gran- og furumaterialet ble samlet inn i området fra ca. 100 til 500 m.o.h. Granmaterialet representerer både kultur- og naturskog, mens hele furumaterialet ble samlet inn i naturskog. Resultatene i denne rapporten sammen med resultater fremskaffet ved NTI og PFI, er lagret i en felles database. Dette gir en unik mulighet til å kople ulike egenskaper for hvert enkelt tre.
Sammendrag
Based on field observations of leaf morphology and variation in chloroplast DNA (cpDNA) in Scandinavia, Norway has been suggested as a suture zone for elm (Ulmus glabra) from different glacial refugia. The aim of this paper was to study the geographical concordance between the maternally inherited cpDNA markers (16 populations) and the assumed polygenic and biparentally inherited leaf traits, studied in a field trial (five populations).Two cpDNA haplotypes were detected, but without geographical structure. Leaf traits showed a gradient from typical ssp. montana traits (relatively long, long tapering, absent acute lobes) in western populations to more ssp. glabra-like traits (relatively broad, short tapering, acute lobes present) in eastern and northern populations.The overall geographical concordance between haplotype distribution and leaf traits was limited, probably owing to different inheritance of cpDNA and leaf traits, but the spatial variation in leaf traits and cpDNA in a subset of common populations (n=5) was compatible with a dual migration of elm to Scandinavia. Both measures suggest a broad suture zone, covering the entire distribution of elm in Norway.The results are discussed in relation to the use of maternally inherited markers, such as cpDNA, in delimiting suture zones.
Forfattere
Ola Ugedal Eva B. Thorstad Tor F. Næsje Laila Saksgård Helge R. Reinertsen Peder Fiske Nils Arne Hvidsten Hans Haavardsholm BlomSammendrag
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Sammendrag
Fine root production, respiration, longevity and mortality are the major processes in carbon dynamics of the forest soils. The objective of the present work was to determine fine root biomass, respiration and root longevity. The study was carried out at a ten year-old stand of planted Norway spruce (Picea abies) (a clearcut, dominated by natural regrowth of Scots pine and birch) and three stands of Norway spruce, approximately 30, 60 and 120 years old, during 2001 and 2002. The stands were located at Nordmoen, a plain of sandy deposits in southeast Norway.Root biomass of both trees and understorey vegetation (0-1, 1-2 and 2-5 mm in diameter) in the humus layer and mineral soil horizons (to depth of 60 cm) was sampled by soil coring. Root respiration was performed in situ, by measuring the CO2 of excavated fine roots by using the CIRAS-I portable gas analyser. For the root turnover study, altogether 60 minirhizotrones were installed and images were processed. Root biomass and necromass (g m-2), specific root length (SRL, m g -1), root length density (RLD, cm cm-3), number of root-tips and mean longevity (y) were estimated.Root biomass was 2-3 times higher in the mineral soil than in the humus horizon. Compared with other stands, root biomass, SRL, RLD and the number of root tips were highest in the 30-year-old stand. At the 10 and 120 year-old stands understorey vegetation roots counted for 70 and 40% of total root biomass, respectively. The amount of necromass at 60 year-old stand was about twice as high (45%) compared to other stands.Root respiration (g C/min./g roots) was significantly lowest at 10-year-old stand. Root respiration among 30, 60 and 120 year-old stands was not significantly different, but it was highest in the 60-year-old stand. The respiration varied seasonally, with high peaks during the summer and lower values during the spring and autumn. Fine root longevity of tree and understorey roots at the 10-year-old stand were 1.2 and 1.4 years, respectively.It is concluded that stand age may influence the dynamics of the fine roots. The complexity of influences will be discussed.