Forest restoration on steep slopes after coal surface mining in Appalachian USA: Soil grading and seeding effects

Abstract

Native trees can be re-established on coal surface mine sites in eastern USA if appropriate reclamation techniques are used. Soil grading and herbaceous vegetation seeding are essential reclamation practices that may influence plant community reestablishment and hydrologic processes that are essential to forested landscapes. We evaluated effects of grading and seeding practices on tree survival and growth, recruitment of plant species, and water infiltration on three steep-slope mine sites in the USA’s central Appalachian coalfield. Half of each site was graded to a smooth condition while the other half was graded less intensively leaving a rough, loose soil surface. Three seeding practices were applied on each grading treatment: a conventional seed mix of grasses and legumes; grasses and legumes selected to be less competitive with planted trees (“tree compatible”); and annual ryegrass (Lolium multiflorum Lam.) alone. Native trees of 13 species were hand-planted on all areas. Over one growing season with adequate rainfall, the survival and average height growth for trees were similar on smooth (69%, 121mm) and loose (70%, 119mm) grading treatments, as well as on the conventional (65%, 116mm), tree-compatible (69%, 129mm), and annual ryegrass (75%, 126mm) seeding treatments. After two years, herbaceous ground cover did not differ among grading treatments but was greater on conventional seeding (83%) than on annual ryegrass seeded areas (55%), while non-planted herbaceous richness (11) and herbaceous native species richness (4.5) were greatest on the annual ryegrass treatment. Water infiltration was slowest on areas with the annual ryegrass seeding treatment and positively correlated with living herbaceous ground cover. Annual ryegrass seeding appears promising as a potential reclamation practice when restoring native forest vegetation where site properties are favorable to native species invasion and where water runoff and potential soil erosion are not short-term concerns.