Can Hardwoods Be Eradicated

The southern pines constitute an important commercial crop, and with proper management their rapid growth insures a renewable resource for the southern United States. On upland pine sites, hardwood shrubs and trees, herbaceous plants, and woody vines all compete with the pines for sunlight, growing space, moisture, and nutrients. The loss in pine volume production that results from this competition has been estimated to be 25 percent in natural stands and 14 percent in plantations (Fitzgerald, Peevy, and Fender 1973). In even-aged management, heavy equipment, nonselective herbicides, and prescribed burns are useful in preparing harvested areas for planting or seeding with pine. Intensive preplant site treatments generally retard hardwood growth or reinvasion until pines dominate the site. For uneven-aged management and some evenaged systems that rely on natural pine reproduction, managers are more restricted in the types of hardwood control measures they employ. Heavy equipment, fire, and nonselective herbicides can damage the seed source and destroy advanced reproduction, thus delaying optimum pine stocking. In 1951 a study (Reynolds 1956) was initiated on the Crossett Experimental Forest in south Arkansas in an upland loblolly/shortleaf pine stand to determine hardwood reinvasion associated with 12 years of annual eradication treatments. A broad array of chemical and mechanical treatments were used to eliminate all hardwood species. This paper evaluates the reinvasion of hardwoods 18 years after treatments were terminated and the apparent effect of those treatments on pine development and growth.