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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

Sammendrag

The Norwegian Monitoring Programme for Forest Damage has now been running for more than 10 years. Its main objective has been to monitor forest condition in relation to air pollution. Surveys of forests are performed on plots in a nation-wide representative grid network (Level 1 in the UN/ECE ICP Forests system), in a network of local county-wise plots, and in a network of intensively monitored plots (Level 2 in the UN/ECE ICP Forests system). Vitality indicators have shown a declining trend as reported earlier, expressed as reduced crown density and more of discoloured trees, particularly in spruce forests. However, results from last year have shown a slight improvement in tree crown condition. Tree mortality in excess of normal is not recorded. Forest condition generally depends upon soil, tree age, climate, pests and diseases, and other natural impact. The observed decreased crown density since 1989 is likely caused by a harsh climate, poor soil conditions and forest diseases. Air pollution loads, add to and interact with these factors. Most likely initiating factors are needed to produce visual symptoms. Summer drought is possibly such a factor of relevance to Norway. The actual effect of the air pollution component is therefore difficult to estimate; however, its importance is not excluded. In future, possible effects of a changed global climate should also be considered. Considering these results it is reasonable to presume that most Norwegian forest ecosystems generally are still in a satisfactory condition.

1998

Sammendrag

Concentrations of pigments in needles of yellowish Norway spruce (Picea abies (L.) Karst.) trees suffering from either N, Mg or K deficiency in field sites in southeast Norway are reported. The yellowish trees had a considerably lower (roughly 50%) pigment concentration, as well as a lower chlorophyll/carotenoid ratio, compared to the green trees within the same sites. Yellowing was interpreted as a general bleaching of colour, as well as a slight turn from the green (chlorophylls) towards yellow (lutein). Concentrations of pigments were highly intercorrelated. N deficiency was especially associated with low a-carotene concentrations. This was interpreted as a-carotene being the most sensitive pigment to stress. However, this pigment might be specifically sensitive to N deficiency. Carbohydrate concentrations were slightly higher in yellowish trees.