The Influence of Different Ground Cover Treatments on the Growth of Outplanted Seedlings on Remined Sites in Eastern Tennessee

There is growing interest in the reforestation of surface mined lands for the production of valuable forest products and creation of quality wildlife habitat. These objectives can be met by planting native woody and herbaceous species on reclaimed surface mines. However, in this region, many of the common ground cover species used to reduce erosion, compete aggressively with tree seedlings, preventing successful establishment. A research project was designed with two main objectives: to investigate the growth and survival of tree seedlings across different herbaceous ground cover treatments, and to identify the relationship between the growth and function of tree seedlings and microsite variables. Five tree species, native to the eastern hardwood forest surrounding the mine site, were planted in 2005. They are: yellow poplar (Liriodendron tulipifera), sugar maple (Acer saccharum), northern red oak (Quercus rubra), eastern redbud (Cercis canadensis), and Virginia pine (Pinus virginiana). Five different ground cover treatments were applied within four replicated planting areas. Two treatments consisted of two different native warm season grass mixes, two were standard reclamation mixes, and one was an unseeded control. Growth and survival, seedling transpiration rate, light measurements, soil respiration, groundcover biomass, and soil chemical properties were measured and analyzed. Survival was significantly different across tree species, with sugar maple having the best overall survival and yellow-poplar the poorest. Seedling survival tended to be greatest within the native warm season grass treatments; however growth rates were variable between all treatments. Seedling survival and growth was related to the amount of herbaceous cover suggesting that tree species react differently to the conditions associated with the surrounding level of herbaceous cover. Moderate ground cover resulted in the best survival, while bare ground or full cover demonstrated the poorest survival rates for northern red oak and eastern redbud. Sugar maple transpiration rate was significantly greater in the moderate (50-75%) cover class during the second growing season. Soil chemical concentrations differed significantly between years, but not between treatments. Soil respiration significantly increased during the two years of this study. The results suggest that moderate herbaceous cover is advantageous for the establishment tree seedlings