INFLUENCE OF SITE FACTORS ON THE SURVIVAL AND GROWTH OF EARLY-AND LATE-SUCCESSIONAL APPALACHIAN HARDWOODS ON RECLAIMED MINED LAND

摘要

In recent years, there has been an upsurge of interest in mined land reforestation with an emphasis on restoring native hardwood species. Research shows that most Appalachian hardwoods could be established on pre-SMCRA sites, but field observations show that many species cannot tolerate the conditions of post-law sites. The purpose of this study was to compare the survival and early growth of hand-planted early- and late-successional timber species (hereafter called softwoods and hardwoods, respectively) as a function of site, specifically slope steepness and slope aspect. This study was conducted on ten sites located in a three-state region of the southern Appalachian coalfields. Four softwoods (American sycamore, green ash, red maple and tulip poplar) and six hardwoods (black cherry, black walnut, northern red oak, sugar maple, white ash, and white oak), all native to the region, were used in the study. Average survival for softwoods was about 50 percent compared to hardwoods at 38 percent. Softwoods were also more productive than hardwoods across sites. Softwood survival increased as a function of increasing slope (P < .0005) and sunny aspects (P < .0001). Softwood tree volume also increased as a function of increasing slope (P < .0001) and sunlight (P < .0008). Hardwood survival and tree volume were not correlated with either slope or aspect. Because of adverse site conditions, hardwoods as a group did not perform well enough to meet regulatory performance standards. The results of this study demonstrate that hand-planted softwoods, while less viable commercially, survive and grow better than hardwoods. Better reclamation techniques are needed to establish native hardwoods successfully in the Appalachian coalfields.