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.
1998
Forfattere
Forde Fjærtoft Birger Eikenes Per Otto Flæte Olav Albert HøibøRedaktører
Bjørn LangerudSammendrag
Det er ikke registrert sammendrag
Forfattere
Bo Eide Hans Fredrik Hoen Ole Hofstad Johnny S. Y. ValenRedaktører
Bjørn LangerudSammendrag
Det er ikke registrert sammendrag
Forfattere
Hans Fredrik Hoen Tron Eid Petter ØkseterRedaktører
Bjørn LangerudSammendrag
Det er ikke registrert sammendrag
Forfattere
Bo Eide Arild VeidahlRedaktører
Bjørn LangerudSammendrag
Det er ikke registrert sammendrag
Forfattere
Knut SolbraaRedaktører
Bjørn LangerudSammendrag
Total avdøing av furu i høytliggende skog og områder eksponert for so mmerfrost helt ned til 300 m.o.h. forklares i hovedsak av angrep fra furuas knopp- og greintørkesopp (G. abietina). Denne skaden skyldes p rimært frost om sommeren og tidlig om høsten, og soppen angriper gjen nom skadde deler av barken. Elgbeiting kan også åpne for soppangrep, og holder plantene nede på en høyde som er lik en vanlig snøhøyde på 60-70 cm. Contortafuru fra 55-60 grader N viste høy resistens mot sop pen, men ble beitet like hardt som vår furu i forsøkene. På syv forsø ksområder ser det ut til at bare syv prosent av totalt 7 600 furuplan ter har muligheter til å utvikle seg til trær med dagens elgtetthet. Snøskytte spilte en uvesentlig rolle i disse forsøkene. Total mortality after planting of P. sylvestris in high-level forests and in areas exposed to summer frosts down to 300 meters a.s.l. is m ainly explained with attacks from Gremmeniella abietina. Primarily th is damage is caused by low temperatures in summer and early autumn, a nd the fungus is supposed to attack through damaged tissues in the ba rk and bark phloem . Moose browsing may also open up for fungal attac ks, and keeps the plants down at heights which are identically with a common snow depth of 60-70 centimeters. P. contorta from 55-60 degre es N was fairly resistant to the fungus, but was browsed as hard as P . sylvestris within the experiments. On seven experimental areas, onl y around 7% of totally 7 600 P. sylvestr is- and P. contorta-plants s eem to have the potential to develop to trees with the moose density of today. P. infestans attacked only a few plants in these experiment s.
Forfattere
Svein Ole BorgenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Anne Sverdrup-Thygeson Fred MidtgaardSammendrag
Det er ikke registrert sammendrag
Sammendrag
Changes in the ectomycorrhizal fungus flora were studied in connection with nitrogen addition and removal experiments in a Norway spruce forest at Gårdsjön, W Sweden during a 5-year period. The above-ground ectomycorrhizal fruit body production was recorded from permanent transect plots, and the below-ground mycorrhizal fine-roots density and morphotype differentiation were studied from soil core samples from the surface root layer. The experiments were performed by adding N-enriched and N-free water, respectively, by means of sprinkling systems. Ammonium nitrate (about 35 kg N ha−1 yr−1) was added to catchment G2 NITREX, whereas at adjacent catchment G1 ROOF ambient N deposition was removed by means of a roof. The addition of N led to a rapid and substantial decrease in species diversity and fruit body production of most species in the NITREX catchment, representing one of very few biological responses to the treatments at Gårdsjön. Stress-intolerant groups such as the initially-dominant genus Cortinarius were almost absent after 5 yr of N addition. Only one dominant species (Cantharellus tubaeformis) increased fruit body production after treatment. In the nitrogen removal (G1 ROOF) experiment, the fruit body production increased strongly the first years, but then declined. No response in the below-ground mycorrhiza and fine-root density and diversity was found. All fine roots had developed ectomycorrhiza. The difference in response above ground and below ground indicates that: (1) the fruit-body producing macrofungi play a minor role below ground, and that (2) there is probably a considerable time-lag in the mycorrhizal fine-root versus fruit body production response to enhanced N levels.
Forfattere
Andries W. Boxman Kai Blanck Tor Erik Brandrud B. A. Emmett Per Gundersen Rene F. Hogervorst O. Janne Kjønaas Hans Persson Volkmar TimmermannSammendrag
Enhancement of the atmospheric N deposition is a serious threat for the structure and function of ecosystems. Here we evaluate the ecological effects of excess N with respect to changes in vegetation and soil biota in a series of experiments along a N gradient across Europe. The aim of this project (NITREX: N saturation EXperiments) is to assess the risk of N saturation and the reversibility of N saturation. At the experimental sites with a low-to-moderate input, N was added (n = 3), while at sites with a high input, N was removed by means of a transparent roof (n = 4). The experiments started between 1989 and 1991. Across the N gradient a positive correlation was found between the N concentration in deposition or soil solution with the N concentration in the needles and in general a negative correlation with the base cations K and Mg. In the N-addition plots there was a tendency towards a decreasing nutrient status of the needles, whereas at one site N-removal led to an improvement. Addition of N hardly affected fine-root biomass production, whereas signs of growth increase were recorded when the input was reduced. Tree growth was accelerated upon input reduction at two of three sites. Manipulation of N input did not alter the decomposition rate, although significant differences between sites were noted. Manipulation of the N input hardly affected the biomass of fungi and bacteria, but a negative relation between the N-addition and part of the soil fauna may be present among sites.