Title: Chemical release of pole-sized trees in a central hardwood clearcut

Author: Van Sambeek, J. W.; Kai, D. Abugarshall; Shenaut, David B.

Year: 1995

Publication: In: Gottschalk, Kurt W.; Fosbroke, Sandra L. C., ed. Proceedings, 10th Central Hardwood Forest Conference; 1995 March 5-8; Morgantown, WV.: Gen. Tech. Rep. NE-197. Radnor, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 152-157

Abstract: Our study evaluated the effectiveness of tree injection and full basal bark treatments using three herbicide formulations at reduced or standard practice rates to release crop trees in an overstocked pole-sized Central Hardwood stand. Herbicides tested included glyphosate (Accord), dicamba only (Banvel CST), and dicamba+2,4-D (Banvel 520). The study was conducted in a mixed hardwood stand in southern Illinois that regenerated following a clearcut harvest 18 years earlier. A highly significant interaction occurred among the six herbicide treatments and the method of application. Full basal bark treatment with any of the three herbicide formulations at either rate produced only light (8 to 25%) crown reduction at 45, 90, and 360 days after treatment (DAT). Tree injection with the high and low rate of glyphosate (4 and 8% ai), the ready-to-use dicamba (10.6% ai), and the registered rates of dicamba+2,4-D (1.7 and 2.4% ai, respectively) caused severe (64 to 78%) crown reduction on the treated trees and shrubs. The shrubs as a group were the most susceptible to the herbicide treatments, while sugar maple was the most herbicide-tolerant tree species. The elms, ashes, low-value hardwoods, and high-value hardwood groups were intermediate in response. Non-treated (crop) trees showed no visible crown reductions or reduced diameter growth following chemical release. We conclude tree injection application of glyphosate or dicamba can be an acceptable method for chemical release of crop trees in mixed hardwood stands.