Evaluation of low spoil compaction techniques for hardwood forest establishment on an eastern Kentucky surface mine

To return surface mined areas in eastern Kentucky to productive forests, the compaction of mine spoil must be minimized or ameliorated. Four methods to reduce compaction on reclaimed surface mines were compared at the Bent Mountain research site in Pike County, Kentucky. The methods included: single shank ripped spoil, triple shank ripped spoil, excavated spoil, and rough graded spoil. Normally graded spoil was also examined as a control to represent a traditional reclamation practice. A single shank ripper was used in gently sloping areas to a depth of ≈ 2-m, while the triple shank ripper was used primarily on level spoil to a depth of ≈ 1.5-m. Both rippers were pulled with a D-11 dozer. Excavated spoil was created by digging out compacted spoil to a depth of ≈ 1-m and dropping it in place. The end dump or rough graded spoil was created by dumping mixed sandstones and shale spoil from a dump truck to a depth of 2 to 2.5-m followed by minimal grading (single pass) with a D-9 dozer to strike-off the piles. All sites were planted with native hardwood species in 2004. Three plots measuring 50 × 50-m were established within each spoil treatment. All trees within the research plots were tagged and have been examined each year for survival and growth characteristics. Bulk density was also measured annually using a nuclear density probe. Preliminary results show several statistically significant differences in tree height and survival. Survival for white oak (Quercus alba) was significantly higher for all reclamation methods compared to the control, and end dump was significantly higher than excavated. Green Ash (Fraxinus pennsylvanica) height was significantly greater for all reclamation methods compared to the control, and single shank ripped was significantly higher than all methods. For black locust (Robinia pseudoacacia) height and northern red oak (Quercus rubra) survival all methods except excavated were significantly greater than the control.