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
Tone GroeggenSammendrag
Forest Officers’ Monitoring Plots. Vitality survey 1999 In 1999 totally 648 plots were assessed comprising 42088 trees (Table 2). The plots are organised in clusters of four plots subjectively chosen in different cutting classes; III (young), IV (intermediate), V (old forest) and one in declining forest. For Norway spruce a reduction in crown density of 0,7% was observed last year. The largest reduction was observed for young stands (1,4%) (Fig. 2). As usual, crown density in the western part of the country was high (Fig. 3). In mid Norway the greatest reduction was observed in old stands whereas in eastern Norway the reduction was greatest in young stands (Table 3). For Scots pine the reduction in 1999 was 1,8%, and it was particularly high in young stands (3,7%). Only in old stands a small increase in crown density was observed. As in the case of Norway spruce the greatest reduction in crown density was observed in eastern Norway. In the western part of the country an increase in crown density was observed (Table 3). For Norway spruce the number of green trees in 1999 were reduced by 1,9%, a decrease which was consistent in all stands (Fig. 4, Table 4). For Scots pine the number of green trees increased in all stands but old stands. For Norway spruce the amount of cones was generally low in 1999 (Fig. 6 and 7). For some parts of northern Norway, the largest amount of cones was observed ever since establishment in 1988. The mortality rate was 0,2%. Infection of needle rust (Chrysomyxa abietis) in mid and northern Norway was less abundant in 1999 than in 1998 and 1997. There were a number of attacks of the fungus in eastern Norway. In 1999 results from Forest officers plots are not consistent with results from Level 1 plots. There was an increase in crown density and less discolouration of trees in level 1 plots. The monitoring of forest tree vitality is motivated by the concern for negative effects due to air pollution, and hence deserves to be given priority.
Forfattere
Svein SolbergSammendrag
Relationships within stands between growth and crown condition are presented. The data set contained about 25000 trees on 500 plots. Growth of single trees was determined by diameter measurements in 1991 and 1996. Diameter increments were recalculated to relative values in two steps; firstly relative to their stem diameter, and secondly relative to reference values for trees in the same plot, having no defoliation or no discoloration. These relative increment values, or growth indices, were distributed on a scale common for all plots, rendering them influenced neither by site and stand properties, nor by social status of each tree. The correlation between crown condition and growth, although of moderate strength, did validate crown condition assessments as a meaningful, but rough measure of forest health or vigour. The relationships were concave, and considerable growth depressions were already found at slight levels of defoliation and discoloration. Growth approached zero as defoliation and discoloration increased towards 100%. These relationships applied for all plots, regardless of their site productivity, development stage or regeneration method
Forfattere
B.J. Stocks M.E. Alexander B.M. Wotton R.A. LanovilleSammendrag
Det er ikke registrert sammendrag
Forfattere
Atle Hindar Erik Norgaard Petter Nilsen R. Høgberget Richard Frederic WrightSammendrag
Det er ikke registrert sammendrag
Forfattere
M. Kurm Ü. TammSammendrag
Det er ikke registrert sammendrag
Forfattere
Kari Anne Sølvernes Øystein Johnsen Gunnar OgnerSammendrag
The impact of elevated CO2 on height increment, phenology, biomass, and concentration of carbohydrates, pigments and elements in clones of Norway spruce (Picea abies (L.) Karst ) were studied in a three year open-top chamber experiment. The CO2-effect on height increment, biomass, and concentration elements of Silver birch (Betula pendula Roth.) was also recorded. The CO2 concentrations were ambient (380 µmol mol-1), approximately 500 and 700 µmol mol-1 CO2 in the chambers. Additionally, an outside control plot was present. Norway spruce were grown in intact profiles of forest soil and in fertilised peat. Silver birch was grown in forest soil only. Phenology and leader shoot extension were recorded regularly. Element concentrations of leaves and needles were analysed at the end of each growth season. At the end of the experiment, carbohydrate and pigment concentrations were also analysed. The impact of elevated CO2 on Silver birch and Norway spruce was small in this experiment. A marginal increase in biomass were recorded in Silver birch and in Norway spruce grown in fertilised peat. Phenology, concentration of elements, C:N ratio, concentrations of carbohydrates and pigments were almost unaffected by elevated CO2. The largest effect on growth and chemical composition were caused by chambers versus outside control plots and difference in nutrient supply (Norway spruce). Significant higher concentration of Al, Na and Fe were recorded in both species in the outside control plots compare to the plants inside the chambers. The increased concentration of these elements could be caused by a higher dust exposure outside the chambers than inside
Forfattere
Gunnar Jansson P.H. StåhlSammendrag
Det er ikke registrert sammendrag
Forfattere
Sjur BaardsenSammendrag
Det er ikke registrert sammendrag
Forfattere
Severin WoxholttSammendrag
Det er ikke registrert sammendrag
Forfattere
Knut SolbraaSammendrag
Det er ikke registrert sammendrag