The Surface Mine Control and Reclamation Act of 1977 dictates the practices and expected outcomes for mine land reclamation in the United States. After 30+ years of implementation, some drawbacks of these practices have surfaced. Specifically, many reclaimed lands in the central Appalachians are in a state of arrested succession. The combination of heavily tracked in soils and the addition of aggressive, often non-native, grasses and forbs creates an environment characterized by high soil bulk density and aggressive ground-layer competition. This results in a situation where trees are unable to recruit and thus many lands are unable to return to original forest cover through natural processes of succession. Here we report on an experiment from eastern Ohio designed to facilitate forest succession. We employed the use of deep ripping and plow-disking surface treatments in a 2x2 factorial design at a 30 yr-old reclamation site. We utilized pure American chestnut (Castanea dentata) and two hybrid forms as a way to investigate chestnut growth on these sites and to advance the national restoration plan under development by the American Chestnut Foundation.
Results/Conclusions
After three growing seasons, seedling survival in the mechanically treated plots was 79-85% compared to 32% in the control plots (Cox Likelihood = 564, df = 3, P < 0.0001). Simply planting chestnut seedlings into existing grassland habitat is ineffective. Some type of surface treatment is necessary to reduce soil bulk density and competition. Results for relative growth rate (RGR) were similar. Seedlings in control plots exhibited the lowest RGR followed by the plow-disk, ripping, and plow-disk+ripping treatment, respectively (all pairwise comparisons P < 0.0001, ANOVA). Ripping of the soil increased RGR significantly (1 df, P < 0.05). This suggests that there may be an advantage to ripping associated with root development that will likely become more obvious with time. While first year results suggested that there might be a hybrid advantage to survival and/or growth, these patterns changed over time. After three years, there was no significant difference in seedling survival among the three chestnut types used; however, pure American chestnut seedlings and the most advanced hybrids performed better than the intermediate hybrid. In sum, surface treatment is necessary to facilitate tree seedling establishment in these habitats and American chestnut and advanced hybrids are good material for forest restoration.
