TREE GROWTH AND NATURAL REGENERATION ON THREE LOOSE-GRADED SURFACE MINE SPOIL TYPES IN KENTUCKY: PRELIMINARY FINDINGS

摘要

Reforestation research on mined lands has shown that loosely graded topsoil, weathered sandstone and/or other non-toxic topsoil substitutes are suitable growing media for establishing native forests in Appalachia. Reclamation practitioners however, have expressed confusion as to what constitutes the best available material other than topsoil. Six research plots were established on a surface mine for the purpose of evaluating the influence of three different loose-graded spoil types on tree performance. The three spoil types are: (1) predominately brown weathered sandstone; (2) predominately gray un-weathered sandstone; and (3) mixed weathered and un-weathered sandstones, and shale material (mine-run spoil). The total area of each plot is approximately 4,050 square meters (one acre). Four species of tree seedlings were planted into the spoils. Growth and survival of the planted trees were evaluated for two years. As an indicator of natural succession potential, percent ground cover of volunteer vegetation on the three spoil types was also evaluated. Preliminary observations indicated that by the second year (2006) after planting, the gray plots had an overall higher average survival (96 percent) than the mixed (84.5 percent) and brown plots (83 percent). The brown sandstone plots however, showed significantly more growth in height and diameter than the gray and mixed plots. Ground cover from natural regeneration was found to be 42.3 percent on the brown plots (40 different species), 2.6 percent on the mixed plots (21 different species), and less than 1 percent on the gray plots (6 different species).