Leader and growth characteristics of eastern white pine associated with white pine weevil attack susceptibility

Abstract

Seven morphological and growth characteristics of 208 eastern white pine (Pinusstrobus L.) leaders, measured when the trees were 22 years old, along with heights and diameters were examined in relation to susceptibility to white pine weevil (Pissodesstrobi Peck.) attack. Bark thickness, depth of inside and outside resin ducts, and diameters of 1978 leaders were positively and significantly correlated (1% level of probability) with number of successful weevil attacks over the previous 11-year period. Correlations between number of weevil attacks and leader length, and numbers of inside and outside resin ducts were not significant. Tree diameter (17 and 22 years) and early height growth (10 and 17 years) were more strongly correlated with numbers of past weevil attacks than leader characteristics were. Leader morphology and growth rates of the trees were highly correlated. Only 13.1% of the tree to tree variation in numbers of successful weevil attacks, determined by multiple stepwise regression with all leader characteristics plus cortical monoterpene concentrations as independent variables, could be attributed to variation in the combined characteristics. This percentage is much too low to be of immediate value in distinguishing highly susceptible from more resistant trees.