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 minirhizotron technique provides the opportunity to perform in situ measurements of fine root dynamics and obtain accurate estimates of fine root production and turnover. The objective of the present work was to determine the fine root longevity and mycorrhization in a Norway spruce chronosequence. The study was carried out on four stands of planted Norway spruce (Picea abies), approximately 10, 30, 60 and 120 years old, during 2001 and 2002. The stands were located at Nordmoen, a plain of sandy deposits in southeast Norway (60o15 N, 11o06 E). For the root turnover study, altogether 60 minirhizotrones were installed and images were processed.Individual fine roots were identified, their mycorrhization assessed, appearance and possible disappearance dated, and growth in length measured. The data set was subjected to a survival analysis, using a Kaplan-Meier product-limit approach. The minirhizotron samples were stratified according to stand age class, and Coxs F-test was used to analyze differences in survival estimates. The analysis may also be extended to consider other covariates such as tree species (spruce, pine or birch), understory vegetation, or soil depth. Typical survival function estimates will be presented, and the influence of stand age on the mycorrhization and the dynamics of the fine roots will be discussed.
Sammendrag
Rapporten presenterer sammendrag av resultatene for 2005 fra tre overvåkingsprogrammer: “Overvåking av langtransportert forurenset luft og nedbør”, “Overvåkingsprogram for skogskader” (OPS) og “Program for terrestrisk naturovervåking” (TOV). Disse tre programmene organiserer omfattende måleprogrammer på luft, vann, jord, skog og annen vegetasjon og akvatisk og terrestrisk fauna. Her presenteres en kortfattet og samlet oversikt over de viktigste resultatene fra de tre overvåkingsprogrammene. For en grundig dokumentasjon om gjennomføring og resultater henvises til rapportene som denne rapporten baserer seg på.
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
Erlend Ystrøm Haartveit Per Otto FlæteSammendrag
The optimal utilisation of a wood raw material is dependent on the wood properties. In this study near infrared (NIR) spectroscopy was used to non-destructively predict density, modulus of elasticity, and modulus of rupture for small clear specimens cut from Picea abies (L.) H. Karst. (Norway spruce) trees.NIR spectra were recorded directly on the wood surface of each specimen as close as possible to the fracture developed during the bending test. Models were calibrated using partial least squares regression. The validation method was test set validation by data splitting.The correlation between predicted and measured values was highest for modulus of elasticity (0.86), followed by modulus of rupture (0.84) and density (0.79). The validation of the models showed that the average accuracies of predictions were 20.3 kg/m3 for density, 1.1 GPa for modulus of elasticity, and 6.1 MPa for modulus of rupture.Results are comparable to what has been found for other tree species, such as Pinus radiata D. Don (radiata pine), Pinus taeda L. (loblolly pine), and Larix decidua Mill. (European larch). Models for predicting density, modulus of elasticity, and modulus of rupture based on NIR spectra outperformed simple regression models using the mean annual ring width as the independent variable.NIR spectroscopy is a rapid tool for characterising organic materials. It requires minimal sample preparation and spectra are collected on solid wood, rapidly and nondestructively. For these reasons the method should be tested in production lines for lumber. In future research we aim for reliable predictions of mechanical properties of industrially manufactured lumber using models based on NIR spectroscopy and multivariate statistical methods.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Anders Often J. Wesenberg Harald BratliSammendrag
Det er ikke registrert sammendrag
Forfattere
Ola Ugedal Eva B. Thorstad Tor F. Næsje Laila Saksgård Helge R. Reinertsen Peder Fiske Nils Arne Hvidsten Hans Haavardsholm BlomSammendrag
Det er ikke registrert sammendrag
Sammendrag
Våren 2002 oppdaget flere skogeiere at en del av granplantene som ble plantet ut høsten før hadde toppavdøing. Samtidig registrerte planteskolebestyrere at noen av granplantene som skulle plantes ut hadde visnesymptomer. Ved Skogforsk ble disse plantene undersøkt ved hjelp av tradisjonelle og moderne molekylære teknikker.
Forfattere
Ola Øyen Bernt-Håvard ØyenSammendrag
Det er ikke registrert sammendrag