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.
1999
Forfattere
Svein SolbergSammendrag
On the local county monitoring plots located throughout Norway a reduction of crown density has been noted during 1988-97. The aim of this study was to determine whether this change could be attributed to normal effects from increased age on the plots.The dataset comprised around 580 plots and 27 000 single trees of Norway spruce, where each tree was provided with ten years of crown density measures. A two step approach was used, firstly to search for an expectancy for normal reduction of crown density by age derived from the dataset, and then to compare this with the actual reduction. The interpretation was somewhat complicated as the various results were tangled into each other.Highly significant correlations were found between crown density and age. The relationship indicated an annual reduction of crown density around 0.12%-units, however, the relationship varied both between years and between regions, and it was not possible to definitely determine whether the relationship was best described by linear or non-linear models.Of major importance here is that the relationship appeared to be influenced by the presence of stresses, which effects tended to be more severe in old stands. Based on this it seems questionable whether an expectancy for normal ageing can be properly defined. However, in the present study it could still be definitely determined that the mean crown density change of -0.41%-units annually was too negative to be attributed to normal ageing, as it was clearly below all the suggested expectancies from the various models.This suggests that the amount of stress in the period under study has been higher than normal, and this encourages the search for causal agents in further studies. Changes in silviculture may have had some influence.The results were valid for most of Norway, with the exception of western and northern regions. Crown density assessments are subjective, which may possibly give erroneous time trends, however, it is argued that this is less likely to be of major importance in the present data.
Forfattere
Tove M. Østensvik H. FossumSammendrag
Det er ikke registrert sammendrag
Forfattere
Anthony A. Hopkin J. Peter HallSammendrag
Det er ikke registrert sammendrag
Forfattere
A. Kinnunen P. PulkkinenSammendrag
Det er ikke registrert sammendrag
Forfattere
Bernt-Håvard Øyen Stein MagnesenSammendrag
I artikkelen ser vi på røynslene frå omlag 70 år med forsøk med lerk som skogstre på Vestlandet
Forfattere
Heleen A. de Wit M. Kotowski Jan MulderSammendrag
Det er ikke registrert sammendrag
Forfattere
Jan Svejgaard JensenSammendrag
Det er ikke registrert sammendrag
Forfattere
Håkon Helgerud Myhra Bohumil KuceraSammendrag
Det er ikke registrert sammendrag
Forfattere
Oddvar SkreSammendrag
The Nordic Subarctic-Subalpine Ecology (NSSE) network was initiated among the Nordic countries in 1977. It was the first joint research initiative under the MAB umbrella in this area and was called the Subarctic Birch Project (SBP). Since the scientific basis for proper ecological planning and use of the subarctic-subalpine birch forest zone was defective in many fundamental areas, the studies were in the forst phase concentrated on basic research in genetic, physiological and ecological adaptations of mountain birch and the interactions between birch and herbivores. The second phase of the study was started in 1989. The aim of this phase is to investigate the response of genetically variant mountain birch, drawn from different provenances, to alterations in climate and nutrients. From these data models of the reaction of mountain birch to global change can be developed. The project group now consists of over ten researchers from Norway, Sweden and Finland. The main organizations participating in the project are: Norwegian Forest Research Institute, Finnish Forest Research Institute, University of Oulu, University of Troms, Abisko Scientific Research Station and Kilpisjrvi Biological Research Station
Forfattere
Bohumil Kucera Håkon Helgerud Myhra Anne Marie GlosliSammendrag
Det er ikke registrert sammendrag