Disking Effects of Fifth-Year Volume Production of Four Eastern Cottonwood Clones Established on an Afforestation Site, Sharkey County, Mississippi
In spring 1995, an eastern cottonwood (Populus delfoides) plantation was established on a former agricultural field in Sharkey County, MS to evaluate the effects of clonal variety and mechanical weed control on aboveground biomass production. Four cottonwood clones, ST-66, ST-72, ST-75 and S7C-1 were planted on a 12 foot x 12 foot spacing and subjected to 2 mechanical weed control treatments (disking in year 1 versus disking in year 1 and 2). Survival in the plantation ranged from 96 percent for ST-66 and S7C-1 to 87 percent for ST-72. But, survival was not influenced by mechanical weed control as it averaged 93 percent for each treatment level. After the fifth growing season, mean cottonwood height ranged from 48.3 feet for ST-66 to 39.8 feet for the other three clones. Similarly, diameter of ST-66 averaged 5.5 inches, while diameter of the other clones averaged 4.8 inches. Two years of mechanical weed control did not improve tree growth as heights averaged 41.8 feet and diameters averaged 4.9 inches regardless of disking treatment. Clonal effects on volume production were obvious after 5 growing seasons, ranging from 1038 feet3 acre-1 outside bark for ST-66 to 574 feet3 acre-1 outside bark for ST-75. Volume inside bark ranged from 631 feet3 acre-1 for ST-66 to 279 feet3 acre-1 for ST-75 Multiple years of mechanical weed control did not improve eastern cottonwood volume production five growing seasons after plantation establishment. Results indicate that eastern cottonwood plantations may be established to rapidly develop a forest structure on a wide range of afforestation sites in the Lower Mississippi River Alluvial Valley.