Establishment of six tree species on deep-tilled minesoil during reclamation

Abstract

Compaction of replaced soil during reclamation of surface-mined land can limit trees. Growth, survival, and water relations of bare-root seedlings of six tree species were followed on deep-tilled and untilled minesoil for 2 years after planting. Trees were planted in rows deep-tilled to 0.7 m and in untilled soil; mowing and herbicides controlled competing vegetation. Leaf area, shoot elongation, and diameter increment were measured in both years, and predawn and midday water potential, and midday stomatal conductance, were measured in the second year. Survival was 16–98% after the first season, varying more among species than between tillage treatments. Rainfall was 50% less in the second season, resulting in a progressive decline in predawn water potential in all treatments and a decrease in survival for several species on untilled soil. Similarly, trees on deep-tilled soil grew slightly more than those on untilled soil in the second season. Tillage effects on survival and growth were not consistently detectable between years, however, and 3 years after planting there were no further changes in survival. Differences in survival and growth among species were large. Survival of black locust was approximately double that of any other species, and its growth was several orders of magnitude greater than that of other species, whereas all of the tulip poplars died by the end of the second season. Over 2 years it appeared that most species had not grown enough either to exploit fully the deep-tilled soil or to be impeded on the untilled soil such that differences in establishment could be detected. The full impact of deep tillage on reclamation with trees must be assessed, however, by following growth and survival over a longer time period