Grigaliūnas, K. and Zolubas, P. 2006. Spruce Radial Increment and Risk to Ips typographus L. Attacks. Baltic Forestry, 12 (1): 34-38

Tree vigour indicated by tree ring increment could be one of the most important factors predisposing spruce trees to bark beetles attacks. Tree ring analysis shows that spruce trees attacked by Ips typographus were growing faster most of their studied life–time in comparison with un–attacked ones nearby, except the last five–year period before attack. Attacked and unattacked spruce trees with codominant crown (Kraft class 2) show the biggest differences in the annual radial increment. Spruce, killed by Ips typographus, suffered more severe drought stress a few years prior to attack and recovered growth slower and weaker than survived trees.

Key words: Norway spruce, Picea abies, spruce bark beetle, Ips typographus, radial increment, cumulative growth, attack risk