Growth of Hardwood Trees On Brown and Gray Mine Spoils in West Virginia.

Surface coal mining in Appalachia drastically disturbs hundreds of hectares of land every year with the removal of valuable and ecologically diverse eastern deciduous forests. After the passage of the Surface Mining Control and Reclamation Act (SMCRA) in 1977, coal mine operators began planting a variety of grasses and legumes as a fast and economical way to re-establish a permanent vegetative cover in order to meet erosion and site stabilization requirements. However, excessive soil compaction and competitive herbaceous cover has arrested the re-colonization of native hardwood tree species on these reclaimed sites. Recently reclamation scientists have encouraged the re-establishment of hardwood forests on surface mined land through careful selection and placement of rooting media and the proper selection and planting of herbaceous and tree species. In an effort to evaluate tree growth on selected spoils and determine the effects of compaction, three 2.8-ha experimental plots were established at Catenary Coal’s Samples Mine in Kanawha County, West Virginia. Two plots were constructed of weathered brown sandstone and the third plot was constructed of un-weathered gray sandstone. Half of each plot was compacted with a D-10 Caterpillar dozer while the other half of the plot was left uncompacted. Each plot was hydroseeded with a low competition herbaceous cover and planted with eleven hardwood tree species on 2.4 by 2.4-m spacing. Soil chemical properties and tree growth have been measured each year since 2005. After seven growing seasons, average tree volume index was consistently higher for trees grown in the brown sandstone treatments, 1534 cm3, compared to 200 cm3 in the gray sandstone treatment. Species which demonstrated the greatest growth on the brown sandstone plots were Dogwood, Red oak, White oak and Tulip-poplar. In this study, compaction was not a significant factor in tree growth. The average pH of brown sandstone was 5.5 to 5.7 while gray sandstone had an average pH of 7.9. The gray sandstone material has resisted breakdown and weathering, and continues to have a high pH and low percentage of fines. As such, the gray sandstone material continued to show slow growth of trees. In October 2011, two new 2.8-ha plots of unweathered gray sandstone were established by the request of Catenary Coal due to concerns with the paucity of growth on the unweathered gray sandstone plot. The two new plots will be measured each year for soil chemical properties and tree growth to determine if un-weathered gray sandstone has the potential to be a suitable rooting medium for reforestation on reclaimed mine sites.