Publications

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.

1987

Abstract

Two years of heavy defoliation of Pinus sylvestris by Neodiprion sertifer caused a volume loss of 33 % during a 9-year period after the defoliation of 90-120 years old pine forests. This loss corresponds to 3 normal annual increments. The increment losses in height, diameter and basal area are calculated both for the old stands and a young one (40 years of age). The economic consequences of the growth loss are also calculated and discussed.

Abstract

Bark beetles are among the few native insects that can kill large numbers of trees in a single year. The present paper reviews recent work on the relationship between conifer resistance to bark beetle attack and tree vigor, e.g. in terms of wood production per unit of foliage. Experimental studies in the Pacific Northwest and the southeast U.S.A., and in Norway, are drawn upon to show that tree resistance to attack may be closely related to the amount of current and stored photosynthate that is available for defense. An experimental approach is advocated to critically test the relationship between host-tree resistance and the limitations on the transfer of critical resources to the site of attack.