Methods

Treatment applications were made to groups of 2-34 trees on the Ferrum College campus. Trees were 5-20 cm diameter at breast height (DBH). Each tree received a numbered tag attached to the stem with a galvanized nail just above ground level. Treatments were applied to groups of trees rather than individual trees because clonal relationships or grafting among stems within a group were possible. Twenty groups of ailanthus trees were identified and randomly assigned to one of four factorial combinations: spring vs. autumn application and cut stump vs. basal bark application (five replicates of each treatment combination). Cut stump application including felling trees just above the surface of the ground and applying a 50% (by volume) aqueous solution of triclopyr (Garlon 3A®) to the entire surface of the freshly cut stump using a squirt bottle. The basal bark application consisted of applying a 20% (by volume) solution of the ester-based formulation of triclopyr (Garlon 4E®) in diesel fuel directly to the basal portion of the uncut stem (approximately 1 m above ground). The solution was applied using a squirt bottle in a 20 cm wide band entirely circling the tree at approximately 1 m above ground.

Fall applications were made in early October, 2003 and spring applications were made in early June, 2004. Evaluations were made in June, 2005. Each tree was evaluated individually and scored using one of four categories based on the extent of control by either crown mortality (for basal bark treatments) or resprouting vigor (cut-stump treatments).

Crown mortality classes included: no apparent effect, minor to moderate effect (< 50% crown mortality), major effect (> 50% crown mortality), or total control (100% crown mortality). Resprouting classes included: no effect (vigorous resprouting), minor effect (some resprouting, but not vigorous), major effect (few resprouts, poor vigor), and total control (no resprouting).

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