Three-year-old Siberian elms (Ulmus pumila L.) were sprayed with six concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) from 0 to 100 ppm. Stem growth was significantly reduced at concentrations of 10 ppm up. Bark abnormalities were observed at concentrations of 25 ppm up. Injury persisted one year after treatment at all but the 0 and 3 ppm concentrations. Forest Sci. 20:287-290.