Survival and growth of hardwoods in brown versus gray sandstone on a surface mine in West Virginia.

Surface mining in West Virginia removes the eastern deciduous forest and reclaiming the mined land to a productive forest must consider soil depth, soil physical and chemical properties, soil compaction, ground cover competition, and tree species selection. Our objective was to evaluate tree survival and growth in weathered brown sandstone and in unweathered gray sandstone. Brown and gray sandstone are often substituted when insufficient native topsoil is available for replacement. Three 2.8-ha plots were constructed with either 1.5 or 1.2 m of brown sandstone, or 1.5 m of gray sandstone at the surface. Half of each plot was compacted with a large dozer. Percent fines (<2 mm) in the upper 20 cm was 61% for brown sandstone and 34% in gray. Brown sandstone's pH was 5.1, while gray sandstone's pH was around 8.0. In March 2005, 2-yr-old seedlings of 11 hardwood species were planted. After 3 yr, tree survival was 86% on 1.5-m gray sandstone, 67% on 1.5-m brown sandstone, and 82% on 1.2-m brown sandstone. Survival was 78% on noncompacted and 79% on compacted areas. Average volume of all trees (height x diameter(2)) was significantly greater on brown sandstone (218 cm(3)) than gray sandstone (45 cm(3)) after 3 yr. Black locust (Robinia pseudoacacia L.) had the highest survival (100%) and significantly greater volume (792 cm(3)) than all other tree species. Survival of the other 10 species varied between 65% for tulip poplar (Liriodendron tulipifera L.) and 92% for redbud (Cercis canadensis L.), and volume varied between 36 cm(3) for white pine (Pinus strobes L.) and 175 cm(3) for tulip poplar. After 3 yr, brown sandstone appears to be a better topsoil material due to the much greater growth of trees, but tree growth over time as these topsoils weather will determine whether these trends continue.