| Summary: | Distribution and occurrence of bark beetles and other forest insects in relation to environmental variation were analysed by multivariate methods. Eight different forest edges were studied using 10 x 10 m sample plots that formed 200 m linear transects perpendicular to the forest edge. Forest edge affected the distribution of insect species only in the edges between mature, non-managed spruce stands and clear cuts or young seedling stands, but not in the pine stands. The occurrence of the selected forest insects mainly depended on variables associated with the amount and quality of suitable woody material. The most significant environmental variables were forest site type, crown canopy coverage, tree species, number of stumps, number of dead spruce trunks and amount of logging waste at site. Quantitative classification of species and sample plots showed that some specialized species ( and ) adapted to mature spruce forests, tended to withdraw from the forest edge to interior stand sites. By contrast many generalized species ( spp., spp. and ) benefitted from cuttings and spread over stand borders into mature forest. Xylechinus pilosus, Cryphalus saltuarius, Polygraphus poligraphusP. subopacusPityogenes chalcographus, P. quadridens, Pissodes Hylurgops palliatus, Tomicus piniperda, DryocoetesTrypodendron lineatum
|
|---|
