Attacks by Ips typographus and Pityogenes chalcographus an windthrown spruces (Picea abies) during the two years following a storm felling

Attacks by Ips typographus and Pityogenes chalcographus during the first 2 yrs after a storm were studied on 1848 windthrown spruces (Picea abies) in southern Sweden. In the first and second summer, 29% and 24%, respectively, of the spruces were attacked by I. typographus, while 21% and 44%, respectively, were attacked by P. chalcographus. High stumps were attacked less frequently than tops, broken trees and windfelled trees with root contact. In both years, trunks in gaps were preferred over those in stands. The proportion of windthrown trees attacked by I. typographus increased with stem diameter, whereas the opposite was true for P. chalcographus. Positive interspecific associations between the species were found on the lower, middle and upper third parts of the trees in the first summer and on the lower part in the second summer. The results are discussed with regard to forest protection and nature conservation.