Patch level variation of bark beetle attack (Col., Scolytidae) on snapped and uprooted trees in Norway spruce primeval natural forest in endemic condition: proportions of colonized surface and variability of ecological conditions

Abstract

Abstract: From two snapped and five uprooted trees, 452 samples were obtained. Ips typographs, Jps amitinus, Dryocoetes spp., Hylurgops palliaus, Hylurgops glabratus, Pityogenes chalcographus, Polygraphus polygraphus, P. subopacus, Pityophthorus pityographus, Xyloterus lineatus and Xilechinus pilosus were present. Single and multiple linear regression were used for assessing the influence of insolation and host factors on the proportion of bark attacked by individual species, on the proportion of bark attacked by all bark beetle groups taken together and on the number of bark beetle groups present on individual trunks. Results show that the proportion of bark colonized by I. typographus is related to the connection of the trunk to roots and to insolation. The proportion of bark attacked by all species together was a function of trunk dimensions. Shaded trunks are attacked only by shade and moisture preferring species, while trunks exposed to higher levels of solar insolation are attacked by higher temperature preferring species on the sunny parts and by shade and moisture preferring species on shady parts.