Site influences herbicide efficiency and growth of planted hardwoods

Several herbicides (dalapon, 2,4-D, simazine, and diphenamid) were evaluated in response to their ability to promote height growth of black walnut, white ash, and yellow poplar through weed control when applied alone and in combinations on an upland and a bottomland site. Griwth benefits were highly dependent on the vegetation on the site. Dalapon and simazine were beneficial on the predominantly grassy upland for all three species whether applied alone or in combination. Simazine and 2,4-D alone or in mixture were beneficial on the bottomland, which contained mostly broadleaved weeds.