The Growth Responses of Picea abies (L.) Karst. to Increment Borer Wounding

ABSTRACT As the use of the increment borer is supposed to be invasive, there is a question of how coring affects subsequent growth or the health of various tree species. Ten Picea abies (L.) Karst. trees in the Beskydy Mts. (Czech Republic) were analysed nine years after coring by an increment borer (June 2011) to determine their anatomical and growth responses to the coring. Cores (13 per tree) were extracted at regular vertical and horizontal distances to evaluate the spatio-temporal pattern of the responses. Sixty percent of trees reacted to the increment boring by creating a vertical crack at the end of year 2011. Traumatic Resin Ducts (TRDs) appeared in all trees relatively soon after coring, with a predominance in the vertical axis. In the horizontal axis, TRDs gradually disappeared with increasing distance from the old coring hole. Overall the spatio-temporal occurrence of TRDs varied in the tree trunk. The immediacy of the response was indirectly dependent on the distance from the 2011 core. Trees responded by growth release the following year after coring as well. The duration of growth disturbances reached three years on average. The results show that P. abies trees are not critically endangered by increment borer coring.