Preparing Planting Sites for Loblolly Pine with Hexazinone, Picloram, or byChopping and Burning

摘要

Four treatments were applied to prepare two upland sites for planting of loblollypine (Pinus taeda L.): (1) preplant broadcasting of extruded pellets of soil-active picloram at the rate of 6 lb acid equivalent per acre in March 1979, (2) preplant broadcasting of 0.12-cubic inch molded pellets of soil-active hexazinone at the rate of 2 lb active ingredient (a.i.) per acre in March 1979, (3) preplant chopping and burning during the summer of 1979, and (4) postplant broadcasting of 0.12-cubic inch molded pellets of hexazinone at the rate of 2 lb a.i. per acre in March 1980. The pine seedlings were hand-planted in January 1980. The herbicides did not injure the seedlings. The size and number of hardwoods after the third growing season were negatively related to the development and yield of planted pine trees after seven growing seasons. Conversely, the percentage of herbaceous plant cover at age 3 was positively related to pine stand development. Hexazinone can be effectively applied either before or after planting as a site-preparation method, but this formulation is less effective than a combination chopping and burning treatment.