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.
2008
Forfattere
Arne SteffenremSammendrag
Wood based products come from a renewable resource playing an important part of the carbon cycle and are therefore regarded environmentally friendly compared to many other alternatives. We might therefore expect a more intensive use of the timber resource in the future. An increase in the supply and net value of timber products from a given area requires more intensive and cost efficient forest management. However, a faster growth rate in general and an increase in the juvenile wood proportion specifically, might come in conflict with the desirable wood quality. Tree breeding programs for Norway spruce (Picea abies L. Karst.) aim to follow up the general demands by providing forestry with plant materials that have superior growth and high wood quality. It is therefore important to establish a better knowledge of the potential of improving wood quality characters in this species through breeding. Characteristics important for structural strength and dimensional stability in conifers are wood density, spiral grain, microfibril angle (MfA) in the S2 layer in the secondary cell wall, branch characteristics and stem straightness. We have studied the genetic variation and correlation patterns for these traits and the direct end-use performance of clearwood samples in terms of stiffness (MOE) and strength (MOR) in four studies of Norway spruce (Paper I-IV). Wood quality traits of defect free wood were studied in Paper I and II. The materials used were 28 and 29 year old progeny trials planted in South East Norway on fertile soils. Significant genetic variation was found for wood density, MfA and spiral grain in both studies (p < 0.05). MOE and MOR, measured by static bending, were studied in one of the materials and the genetic variation was found to be highly significant (p < 0.01). There was also significant genetic variation (p < 0.05) in MOE estimated (MOEest) from wood density and the x-ray diffractometry pattern from the S2 layer obtained by SilviScan®-3. Genetic parameters were estimated in Paper II with large standard errors. The parameters must therefore be used with caution and preferably with support from other studies. We could confirm earlier studies of high genetic variation and low genotype by environment interactions (GxE) for wood density and spiral grain. Parameter estimates for MfA and MOEest, from one site, suggest that these are under moderate to strong genetic control in Norway spruce. Phenotypic correlations between growth traits (height and diameter growth) and wood quality traits were negative for wood density, positive for MfA and negative for MOEest. Genetic relationships showed the same trends for diameter growth, but not for height growth. The genetic and environmental variation in branch characteristics (Paper III and IV) were studied in three sets of progeny trials that were 22, 28 and 29 years old from planting. Stem straightness was studied in the 22-year old trial only. The branch diameter was highly influenced by site index and spacing. Number of branches formed and stem straightness seems to be under stronger genetic control. Individual tree heritabilities for growth traits, branch diameter and stem straightness were estimated in the 22-year old progeny trial planted at two sites. The trials were planted with different spacing, which allowed us to study genotype by spacing interactions. Heritability for growth traits and branch diameter across sites were moderate (0.14 - 0.19) compared to the higher values found for stem straightness (0.28). GxE, and thereby genotype by spacing interactions were not important for any of the traits. Heritability for number of branches, estimated from one of the sites, was 0.24. There was a strong and positive genetic correlation between growth traits and branch diameter. The presence of genetic variation for most wood quality traits suggests that these can be improved by tree breeding. However, genetic correlations with growth traits indicate that selection solely for growth might have adverse effects on wood quality. It is therefore important to balance the gain in growth and wood quality. Implementation of several adversely correlated traits in a breeding program reduces its efficiency. It is therefore essential that tree breeding, silvicultural practices and forest industrial needs interact when developing tree breeding programs to obtain an optimal strategy for selection and utilization of improved plant materials.
Forfattere
Maria Herrero Brita Toppe Trond RafossSammendrag
In November 2002, P.ramorum was detected for the first time in Norway (1). It was isolated from Rhododendron catawbiense imported earlier the same year. After the first detection the Norwegian Food Safety Authority has carried out surveys from 2003 to 2006. The surveys were first directed to nurseries and garden centres. Most of the positive findings were on Rhododendron spp., but one sample of Pieris japonica, one of Kalmia sp., one of Syringa sp. and one of Viburnum sp. were also positive. In 2005 and 2006, P. ramorum was isolated from well-established viburnum and rhododendron plants in private gardens, parks and public greens. Infections were detected on well-established plants from 9 different outdoor sites. While the positive samples from nurseries were spread over the country, the positives found on well-established plants were concentrated in and around the cities of Bergen and Stavanger on the southwestern coast of Norway. This part of the country has cool summers, mild winters and more than 2000 mm of annual precipitation. In 2006, P. ramorum was found in private gardens in the eastern part of the country on young recently introduced plants. P. ramorum was found in 12 import shipments, mainly on rhododendron, but also on a viburnum sample.
Forfattere
Line RosefSammendrag
Questions: Could the seed bank increase biodiversity during restoration of abandoned, species-poor, formerly cultivated vegetation? Is it possible to identify how climate, soil and former and present management and vegetation affected the seed bank? Location: The study sites were eight abandoned grasslands, four in Orkdal, central Norway and four in Gaular, western Norway. Methods: 144 seed bank samples were collected from three depths. Each sample was sown and placed in a greenhouse. After three months, the trays were dried and stored at 4°C in a dry place for two months. This was repeated twice. Results: There was a separation of the two regions along the first DCA axis in both the seed bank and in the vegetation analysis and also a clear separation of the seed bank from the vegetation along the second axis. These results are caused by differences in former management as well as temperature, precipitation and soil type between Gaular and Orkdal. We found more annuals, short-lived species and species demanding light open conditions in the seed bank than in the vegetation probably because these species have the capacity for producing persistent seeds. Most of the species found only in the seed bank were found in very few samples and with few individuals. Conclusion: These results suggest that it may be difficult to increase vegetation biodiversity through restoration of grasslands such as those investigated if the natural soil seed bank is the main seed source.
Forfattere
Line RosefSammendrag
Det er ikke registrert sammendrag
Forfattere
Kirsten TørresenSammendrag
Foreløpige resultater fra feltforsøk og labforsøk for å studere spiring og frøhvile til vårrybs ble presentert.
Sammendrag
På oppdrag fra Fylkesmannen i Vestfold har Bioforsk Jord og miljø beregnet flateerosjon fra landbruksarealer i Vestfold i 2007. Beregningene er utført med erosjonsmodellen GIS avrenning, som kombinerer Skog og landskap (tidligere NIJOS)’ erosjonsrisikokart med registerdata fra tilskuddsordningene for endret jordarbeiding. Erosjon er beregnet både for dagens drift og for ulike tiltaksalternativer der mer areal legges i stubb. Resultatene er summert opp pr kommune. Totalt for hele Vestfold er det bare mindre endringer i beregnet flateerosjon fra 2006 til 2007, men sammenligningen er noe usikker pga ulikt beregningsgrunnlag. Rapporten gir også en beskrivelse av ulike indikatorer for å måle endringer i erosjonsrisiko som følge av omlegging i driftspraksis. Disse indikatorene vil kunne være aktuelle ved Fylkesmannens oppfølging av de regionale miljøprogrammene.
Sammendrag
Reiselivet i Norge har de siste tiåra vært oppmerksomme på landskapsendringene som skjer i Norge. I følge reiselivsnæringa truer gjengroing av kulturlandskapet viktige segmenter innen det norske reiselivet. Samtidig legges det årlig ned et sted mellom 1500 - 2000 gardsbruk i Norge.
Forfattere
Marianne BechmannSammendrag
Erosjon og næringsstofftap forårsaker problemer for vannkvaliteten i områder med jordbruksdrift og det blir satt inn omfattende tiltak for å redusere disse tapene. Program for jord- og vannovervåking i landbruket (JOVA) har dokumentert tiltaksgjennomføringen i et utvalg av jordbruksområder fra Bodø i Nord til Grimstad i sør.
Forfattere
Trygve S. Aamlid Agnar KvalbeinSammendrag
Foredraget presenterer praktisk planleggingsverktøy til bruk ved planelgging av gjødsling på fotballbaner og gir noen eksempler.
Forfattere
Agnar KvalbeinSammendrag
Presentasjon av gjødslingsstrategier. Hvilke næringsstoffer skal vi styre etter? Hva er prinsippene for dynamisk, balansert gjødsling. Diskusjon av ulike formuleringer og presentasjon av to ulike gjødselplaner basert på henholdsvis fast og flytende gjødsel. Sammenhengen mellom nitrogentilgang og plantenes skudd/rot-forhold.