NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.



Change in crown density for Norway spruce (Picea abies) from 1988 to 1993 in three independent forest monitoring projects in southern Norway were compared. An increase in crown density was found in a countywide systematic random sample, whie measurements taken in old-growth forests reported a decline. These contradictory results may be due to: (1) high sensitivity of high-elevation forests to various kinds of environmental impact; (2) differences in stand age and management practice; and (3) different sensitivity to long distance airborne pollutants. The systematic random sample encompassed stans of several age classes from two counties, while the two other studies were restricted to old-growth forest in two smaller are as. A possibe explanation of the differences is thus that the three studies refer to differet popuations as a resut of different sampling strategies.