| Popis: |
Resistance to pulsed electric current (ER) applied to the cambium layer was studied in black locust trees, Robinia pseudoacacia L., in relation to tree thrift indices, and particularly to intensity of current-season attacks by the locust borer Megacyllene robinia. A total of 415 borer attacks were sustained by 241 trees, with a maximum of 20 attacks per tree. Although variation in the data was high both within and among study sites, ER was positively correlated with borer mines per tree and with increased degrees of tree suppression, represented by dominance classes. ER ranged from 2 to 32 kohms per tree, with roughly 95% of the trees reading less than 25 kohms. Borer mines per tree were also correlated with tree dominance class, with more attacks incurred by increasingly suppressed trees. |
