Evaluation of Small Tree and Shrub Plantings on Reclaimed Surface Mines in West Virginia

Abstract

Evaluation of Small Tree and Shrub Plantings on Reclaimed Surface Mines in West Virginia Alexis Monteleone Hundreds of acres of mined land are reclaimed annually in West Virginia (WV) and are planted with hardwood tree species. Forestry and wildlife post-mining land uses require the planting of specific tree species designated by the individual mine permit and planting plan, which generally includes planting of commercially-valuable hardwood species. Establishment and growth of fruitand nut-producing small tree and native shrub species has not been studied for reforestation plantings on surface mines. Though these species are not generally planted as part of forestry reclamation, they are commonly found in forest ecosystems of WV and are often an important component, contributing to both structural and floral species diversity. Survival and growth of 20 species of mastand fruit-producing shrubs and small trees were evaluated to better understand their suitability for reclamation plantings. Seedlings were planted in graded overburden material during 2008 and 2010 on four reclaimed surface coal mines in WV. The selected sites were reclaimed using conventional methods. The experiment was a completely randomized block design with four blocks per site, two east-facing and two west-facing. Each block was comprised of 20 monoculture species plots, and within each plot 25 individuals were planted on 2.4 m x 2.4 m spacing. Initial data on survival and growth of these species was collected in 2008 and 2010 a growing season after establishment. Survival and growth of these species were measured again in 2015 and 2016 to determine individual species performance over time. In general, 18 of the 20 species included in this study were successful in establishing and growing on the reclaimed surface mine sites in West Virginia. The exceptions were pawpaw (Asimina triloba L.) on the sites planted in 2008 and blueberry (Vaccinium corymbosum L.) on the sites planted in 2010. The best performing species overall were black chokeberry (Aronia melanocarpa Michx.) at 56% survival, black cherry (Prunus serotina Ehrh.) at 55%, Washington hawthorn (Crataegus phaenopyrum L. f.) at 54%, nannyberry (Viburnum lentago L.) at 52%, and hazelnut (Corylus avellana L.) at 50%. The two species that experienced the highest mortality were flowering dogwood (Cornus florida L.) at 10% and pawpaw at 9%. Across all species, Elk Run showed the highest survival percentage at 51%, Fola and ICG were between 40 and 45%, while Hobet had the lowest at 25%. Although survival and some height measurements were found to be greater on west-facing aspects when compared with east-facing aspects in this study, the results were not strongly correlated and skewed by a few species that performed particularly well on west-facing aspects at one site. The effect of aspect for the majority of species in this study and at most sites was not significant at the individual species level. Soil properties varied widely among sites with pH ranging from 3.4 at Fola to 7.5 at ICG, fines ranged from 58% at ICG to 82% at Hobet, and elemental concentrations showed large variability. When compared to the growth rates exhibited by these species in horticultural, forestry, or agricultural settings, the growth rates were considerably less in this project with these mine soil conditions. In order to correlate average heights observed with soil properties in the mine soils, stepwise regression, principle component analysis and principle component regression were used. The analysis showed potassium, phosphorus, and aluminum as being the most strongly correlated (R of 0.20) with plant height when all species’ average heights at all four sites were considered. Since the mine soil properties were so different at each site, separate regressions were performed. Copper was the most significant soil property for height at Elk Run and ICG, no soil properties were significant at Fola, and EC and Na were important at Hobet. The results of this study demonstrated that several small tree and shrub species have potential for planting on surface mines in West Virginia. Species like black chokeberry, black cherry, Washington hawthorn, and nannyberry, which had greater than 50% survival after 6 or 8 years, are the most likely candidates. Other species which are adapted to better soil conditions did not perform well and should not be considered for plantings.