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
Aims Beech (Fagus sylvatica L.) is an important species in natural and managed forests in Europe. This drought-sensitive species dominates even-aged stands as well more natural stands composed of a mixture of tree species, age and size classes. This study evaluates the extent that heterogeneity in spacing and tree diameter affect the seasonal availability and use of water. Methods Two stands were evaluated: 1) a heterogeneous forest remnant (NAT) with trees up to ca. 300 years old, a mean top height of 28.4 m, and a total of 733 stems ha-1 with stem diameters averaging 18 cm and 2) an even-aged 80-year old stand (MAN), with a height of 25 m, and a total of 283 stems ha-1 with diameters averaging 38 cm. Stem sap flow, Js (g m-2 s-1), was continuously measured in 12 (MAN) and 13 (NAT) trees using 20 mm long heat dissipation sensors. Individual tree measures of sap flow were correlated using non-linear statistical methods with air vapour pressure deficit (D, hPa) and global radiation (Rg, J m-2 day-1), along with contraints imposed by reductions in soil water content (SWC). Soil water content was measured as volumetric % using time domain reflectometry. Important findings The daily integrated Js (Js-sum) for trees growing in the evenly spaced MAN stand and trees in canopy and closed forest positions in NAT stand decreased as the availability of soil moisture was reduced. In the heterogeneous NAT stand, SWC in a recently formed canopy gap remained high throughout the vegetation period. Based on regression models, the predicted relative decrease in Js-sum for dry relative to moist soil water conditions in the closed forest (at mean daily D = 10 hPa) was 7-11% for trees near the gap and 39-42% for trees in the closed forest. In MAN the reduction in Js-sum was 29% in dry relative to moist conditions. Js-sum in the outer 20 mm of the xylem in NAT was lower than that in MAN and the rate of decline in Js with xylem depth was less in NAT than in MAN. In MAN, Js-sum in deep and outer xylem was negatively affected at low soil moisture availability; in NAT this was the case for only the outer xylem indicating that deep roots could be important in supplying water at times of low soil moisture in the upper soil.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Bjørk elsker lys, men stiller ellers lite krav til voksested. Vi har tre arter bjørk i Norge. Disse krysser seg med hverandre og lager variasjon som av og til gjør det vanskelig å trekke tydelige grenser mellom artene.
Sammendrag
Eika er kongen blant trærne. Det blir sagt at den bruker 500 år på å vokse og 500 år på å dø. Mollestadeika er trolig rundt 1000 år gammel og er ett av Norges eldste trær. Det fi nnes to viltvoksende arter eik i Norge. Dette er varmekjære treslag som inngår i det vi kaller edelløvskog.
Sammendrag
Gran og furu finnes omtrent over hele landet og er de vanligste treslagene i Norge. De er også de viktigste artene økonomisk. Gran er skyggetålende og fuktighetskrevende, mens furu er lyskrevende og tørketålende.
Sammendrag
Rogn vokser over hele landet både i lavlandet og opp i fjellskogen. Det finnes i tillegg tolv andre viltvoksende arter i rogn- og asalslekta i Norge. Flere av disse finnes ikke noe annet sted i verden.
Sammendrag
Frukttrær som epler, pærer, plommer og kirsebær blir dyrket i sørlige og varme strøk i Norge. Alle disse frukttrærne hører hjemme i rosefamilien. Visste du at det også finnes ville epletrær og kirsebærtrær i norsk natur?
Sammendrag
The aim of this study was to use energy-dispersive X-ray spectroscopy (EDX) to localize chitosan in the cell wall of chitosan-impregnated Scots pine. It was of interest to investigate the concentration of chitosan in wood to gain further knowledge and understanding of the distribution of chitosan in the wooden matrix. After deacetylation, chitosan was re-acetylated with chloroacetic anhydride to achieve a covalent bonding of chloride to the chitosan polymer. Chloride-labelled chitosan was measured by EDX using a scanning electron microscope and described as chloride intensity. Analysis of free chloride anions was performed by dialysis and inductively coupled plasma atomic emission spectroscopy. There was a significant correlation between the molecular weight of chitosan and the intensity of covalentbonded chloride to the chitosan polymer. High molecular weight chitosan showed a better interaction with the cell wall structure than low molecular chitosan.
Sammendrag
In Norway log buildings are normally produced from logs canted on two sides. The canted faces are prone to crack formation during drying. This can cause some disadvantages, e.g. the cracks can trap water from rainfall, because the canted faces form the wall surfaces in the log buildings.
Sammendrag
The objective of the study was to assess the influence of wood properties on copper leaching from wood treated with preservatives. Scots pine (Pinus sylvestris L.) trees were harvested from two different stands in Norway and one in Denmark. Sapwood was cut to samples (20 x 20 x 50 mm) in as many layers as the radial size allowed. Within this material, it is possible to trace the individual sample to its original position in the stem. Approximately half of the samples were treated with Wolmanit CX-8 and half with Tanalith. All samples were conditioned, impregnated with preservatives and leached according to EN84. Copper and boron content in water samples was determined by an ICP (Inductively Coupled Plasma) technique. The variation in leachability within trees, between trees and between different stands was studied. Statistical analyses showed that trees from the south are more prone to leaching and that samples from the lowest part of the tree fixate less preservative than those from the upper parts. In addition, drying method of the sample had an influence and differences were also noted between products used in the study.