Assessing the Use of Chopper Herbicide for Establishing Hardwood Plantations on a Cutover Site

Abstract

Abstract Successful establishment of hardwood plantations requires effective weed management. Mechanical weed control is inefficient, and few herbicides are available for use in hardwood plantations. In an effort to identify new chemical control options, the potential of imazapyr (Chopper herbicide) for site preparation prior to planting three common southern hardwood species was assessed. Twelve site preparation treatments were tested using Chopper applied at four rates and three timings prior to planting. Each site preparation rate and time pairing was repeated under two postplant herbicide regimes—directed glyphosate (Accord herbicide) sprays designed to maintain weed-free conditions and a single broadcast sulfometuron methyl (Oust herbicide) treatment designed to test a potential operational sequencing of Chopper site preparation followed by herbaceous weed control. Although results must be evaluated in the context of a single site and set of environmental conditions, they demonstrate the utility of Chopper herbicide for site preparation prior to planting hardwoods. For sycamore (Platanus occidentalis L.)and sweetgum (Liquidambar styraciflua L.),site preparation before the end of July with Chopper rates up to 64 oz/ac improved survival and growth over postplant treatments alone. For later season applications, sycamore and sweetgum were more sensitive to the Chopper site preparation rate. For Oct. site preparation, Chopper rates above 16 oz/ac adversely affected planted sycamore seedlings and rates greater than 32 oz/ac adversely effected planted sweetgum seedlings. Cherrybark oak (Quercus pagoda Raf.)performed best using the highest Chopper rate of 64 oz/ac regardless of timing. South. J. Appl. For. 28(3):163–170.