Abstract
Reclamation of surface mined sites to forests is a preferred post-mining land use option, but performance of planted trees on such sites is variable. American chestnut (Castanea dentata (Marsh.) Borkh.) is a threatened forest tree in the eastern USA that may become an important species option for mine reclamation. Chestnut restoration using backcross hybrids that incorporate blight resistance may be targeted to the Appalachian coal mining region, which corresponds closely with the species’ native range. Thus, it is important to understand how chestnut hybrids perform relative to progenitors on reclamation sites to develop restoration prescriptions. Seeds of parents and three backcross generations of chestnut (100% American, 100% Chinese, and BC1F3, BC2F3, and BC3F2 hybrids) were planted into mine soils in West Virginia, USA with shelter treatments. Survival for all stock types was 44% after 8 years (American 39%, Chinese 77%, BC1F3 40%, BC2F3 28%, and BC3F2 35%). Height for all stock types was 33 cm after 8 years (American 28 cm, Chinese 67 cm, BC1F3 30 cm, BC2F3 21 cm, and BC3F2 20 cm). At another site a year later, seedlings of the chestnut stock types were planted into brown (pH 4.6) or gray sandstone (pH 6.3) mine soils and seedling survival across all stock types was 58% after 7 years. Chinese had the highest survival at 82%, while the others ranged from 38 to 66%. Height was 63 cm for all stock types after 7 years. More advanced backcross hybrids (BC2F3 and BC3F2) had the lowest vigor ratings at both sites after 7–8 years. Our results indicate that surface mines in Appalachia may provide a land base for planting blight-resistant chestnuts, although Chinese chestnut outperformed American chestnut and later generation backcross hybrids. As blight-resistant chestnuts establish and spread after planting, chestnut trees may become a component of the forest canopy again and possibly occupy its former niche, but their spread may alter future forest stand dynamics.
Highlights
Surface coal mining has disrupted about 2.5 million ha of eastern USA forests since 1930 (Paone et al 1978; Plass 2000)
Our results indicate that surface mines in Appalachia may provide a land base for planting blight-resistant chestnuts, Chinese chestnut outperformed American chestnut and later generation backcross hybrids
There were no differences in the mine soil chemical properties across the areas with and without shelters
Summary
Surface coal mining has disrupted about 2.5 million ha of eastern USA forests since 1930 (Paone et al 1978; Plass 2000). With the passage of a national surface mining law in the 1970s, most surface mined land in Appalachia was reclaimed to pasture and hay land or wildlife habitat post-mining land uses (Plass 2000; Angel et al 2005) rather than returning the land to its original forest pre-mining land use. Since the early 2000s, reclamation to forests has become a more preferred post-mining land use option than pasture or hay land in Appalachia (Angel et al 2009). The FRA recommends the following steps: (i) Create a suitable rooting medium for good tree growth that is no less than 1.3 m deep and comprised of topsoil, weathered sandstone, and/or the best available material; (ii) Loosely grade the topsoil or topsoil substitutes established in step one to create a non-compacted growth medium; (iii) Use ground covers that are compatible with growing trees; (iv) Plant two types of trees—(1) early succession species for wildlife and soil stability, and (2) commercially valuable crop trees; (v) Use proper tree planting techniques (Burger et al 2005). Recent research has shown successful establishment of native hardwood trees when applying all five steps of the FRA (Angel et al 2008; Wilson-Kokes et al 2013a, b)
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