Development of Understory Vegetation in Pine and Pine-Hardwood Shelterwood Stands in the Ouachita Mountains-the First 3 Years

The shelterwood reproduction cutting method using two overstory compositions (a pine basal area of 30 ft* per acre with and without 15 ft’ per acre of hardwoods) and two methods of submerchantable hardwood control (chain-saw felling with and without stump-applied herbicide) was tested in a 2x2 factorial, split-plot design with four randomized complete blocks. Production of sound pine seeds after treatment was marginal to good, averaging 39,000,28,000, and 155,000 per acre in 1990, 1991, and 1992, respectively. AAer the third growing season, pine seedlings averaged 1,550 stems per acre and 54 percent milacre stocking; no significant differences occurred between either overstory or hardwood control treatments. Hardwood reproduction after treatment generally reflected the amount and composition that was present in the original stand, with oaks averaging 8 IO rootstocks per acre and 48 percent milacre stocking. The size of pine reproduction in the pine overstory treatment was twice as large as that in the pine-hardwood overstory treatment, and fewer of the stems in the pine overstory treatment were overtopped by understory vegetation. Total coverage of understory vegetation after 3 years was greater in the pine overstory treatment (68 percent) than in the pine-hardwood overstory treatment (46 percent) and was slightly greater for manual than chemical hardwood control (60 versus 55 percent). Results indicate that 15 fi2 per acre of scattered hardwoods can be retained through at least 3 years after harvest, but additional monitoring will be needed to determine the long-term success of reproduction. Early results suggest that the herbicide treatment was not justified in the stand and site conditions tested in this study; contributing factors were the abundant pine seed production and low levels of competing vegetation.