Evaluation of four herbicides and tillage for weed control on third year growth of tree seedlings

Azafenidin (AZ), pendimethalin, simazine, and sulfometuron (SF) were applied alone and in combination to black cherry, black walnut, eastern white pine, flowering dogwood, northern bayberry, northern red oak, Siberian crabapple, white ash, white oak, and yellow poplar seedlings grown for 2 yr in the field. There were significant differences in diameter, height, and stem volume among the treatments for every species after the third growing season. Tillage significantly increased tree growth over controls for most species. No single herbicide treatment ranked best for all tree species but comparison of the mean ranks of the treatments for all species indicated that AZ resulted in the best growth. Post–bud-break applications of SF and AZ were no better than untreated controls for most species. Herbicide treatments did not affect tree survival over years but exhibited potential for better growth in establishment years.