Four Years of Hardwood Tree Growth on Mountaintop Surface Mines in West Virginia.

Surface mining in West Virginia has been taking place for nearly a century.  Most of this land was once covered in eastern deciduous forest and returning the post-mined land to a productive forest has become a priority.  The objective of this research is to evaluate tree survival and growth in weathered brown sandstone and in unweathered gray sandstone.  Three, 2.8-ha plots were constructed with: 1) 1.5 m of weathered brown sandstone, 2) 1.2 m of weathered brown sandstone, and 3) 1.5 m of unweathered gray sandstone.  Half of each 2.8-ha plot was compacted, where dozer tracks completely covered the surface, while the other half had only one pass of a dozer.  Percent fines in the upper 20 cm on brown sandstone increased from 51% the first year to 61% the fourth year, while on the gray sandstone it decreased from 38% to 34%.  Brown sandstone’s pH of 5.1 stayed consistent over four years, while gray sandstone’s pH was 7.9 the first year and increased to 8.4 by year four.  In March 2005, 11 hardwood species were planted in each plot.  After one growing season, tree survival on the non-compacted areas of each treatment was >99% across all species, whereas the compacted areas showed 88% tree survival.  By year four, survival had decreased to 78% on non-compacted areas and 79% on compacted.  Height and diameter for each species was obtained each year of the study.  In year one there was little difference between treatments across all species (average height 38.6 cm for 1.5 m brown sandstone vs. 38.9 cm for 1.5 m gray sandstone).  By year four, average height of trees on brown sandstone was significantly greater than on gray sandstone.