HEIGHT OF THREE HARDWOOD SPECIES GROWING ON MINE SITES RECLAIMED USING THE FORESTRY RECLAMATION APPROACH COMPARED TO NATURAL CONDITIONS 1

Abstract

Coal is an important source of energy for electricity and is used in making steel and various other products. West Virginia is the largest coal producing state within the Appalachian region. Surface mining of coal drastically disturbs ecologically diverse forests and the reforestation of these areas after mining is an important first step to helping restore their ecosystem functions. After mining, operators are often left with brown and gray sandstone to use as topsoil substitutes. Brown sandstone has been more weathered and has physical and chemical properties that are better for tree growth (lower pH, higher percent fines, and higher available nutrients) than gray sandstone. Two study sites were established on former mine sites in West Virginia to assess the effects of brown and gray sandstone, with and without mulch treatments, on tree establishment. Tree growth data for tulip poplar (Liriodendron tulipifera L.), white oak (Quercus alba L.) and northern red oak (Q. rubra L.), and for soil samples (analyzed for pH, EC, percent fines, and extractable nutrients) have been collected annually for the last 10 years. The pH of brown sandstone was 5.2 to 5.4, gray sandstone was 6.5 to 6.8, and mulch treatments were 7.0. Percent fines ranged from 42 to 60% on all treatments. The mulch treatment had high levels of Ca (197 cmolc/kg). The height growth of each tree species on both mine sites was compared to the growth of trees growing on clear-cut areas at the Fernow Forest, WV. In addition, an estimated site index prior to disturbance was calculated and used to predict tree growth rates based on NRCS soil survey data. Tree heights (25 to 175 cm) on gray sandstone were significantly lower than height on brown sandstone (197 to 544 cm) for all three species. Trees on mulched plots were up to 229 cm taller than trees on un-mulched plots. Tulip poplar height on the brown treatment (544 cm) was greater than on a clear-cut area with a site index 62 at 10 years (503 cm). Tree heights on average were 50% lower on mined sites compared to heights calculated from pre-mining site indices.