Second Year Response of Appalachian Mixed Hardwoods to Soil Surface Grading and Herbaceous Ground Cover on Reclaimed Mine Land

Abstract. Recent experience suggests that native Appalachian hardwood trees can be successfully established on coal surface mining sites if appropriate reclamation techniques are used. The Forestry Reclamation Approach (FRA) is a set of mine reclamation techniques developed for that purpose. Questions remain regarding how soil surface grading and choice of herbaceous vegetation affect tree survival, soil erosion and plant succession. An experiment was begun in the spring of 2008 with the goal of evaluating effects of grading and hydroseeding treatments prescribed by the FRA on reforestation success. Three steep (approximately 60% slopes) reclaimed mine sites were prepared in the coalfield of southwest Virginia. Half of each site was graded using conventional pre-FRA grading practices that cause compaction of the surface soil. The other half was loose-graded as per FRA recommendations. Within each grading treatment at each site, one third of the area was seeded with a conventional herbaceous vegetation mix that included competitive grasses and legumes; one third with a tree-compatible herbaceous mix comprised of less competitive grasses and legumes; and one third with 100% annual ryegrass. All experimental areas were planted with the same mix of native hardwood trees. Tree survival over one growing season was similar on the loose (71%) and compacted (70%) grading treatments, as well as on the conventional (65%), tree-compatible (71%), and annual ryegrass (75%) revegetation treatments. Recruitment diversity of nonplanted species was greatest on the annual ryegrass treatment (12 volunteer species), suggesting this re-vegetation practice creates the most favorable conditions for natural succession. Soil erosion rates were significantly higher on the compacted treatment (-8mm soil soil surface change) than on the loose-graded treatment (+10mm soil soil surface change) over the course of two years. The annual ryegrass treatment produced significantly less ground cover (55% total) after two years than the conventional ground cover treatment (83% total), but this did not result in greater soil erosion.