Long-term effects in vegetation and soils at two 19th century iron furnace sites in southeastern Ohio, USA.

Abstract: Deciduous forests are regenerating following industrial disturbance in large areas of eastern North America and western Europe. To understand the long-term process of forest regeneration, the microenvironment and flora of post-industrial plots were compared with non-industrial controls at two 19th century iron furnace sites in southeastern Ohio, USA. Post-industrial plots had a shrub and canopy structure similar to controls, and showed comparable litter cover, soil organic content, and bulk density. Post-industrial and control plots remained clearly distinguishable in soil moisture, pH, and cation concentrations, however, consistent with leaching from industrial waste. Post-industrial areas were dominated by shade-tolerant plant species typical of long-established second-growth forest in the region, suggesting functional suitability of the industrial soils and an abundance of potential colonists. Open-habitat species persisted in post-industrial plots, showing a significantly higher richness and abundance than control plots. Annual growth increments showed later establishment of canopy tree species in the post-industrial plots, suggesting that the presence of open-habitat species reflected delayed canopy closure in the post-industrial area. Slag, clinker, iron–ore, and terrace microsites consistently differed in species composition within the post-industrial areas despite their relatively small size and close proximity. Thus, industrial effects appear to be perpetuated by long-term persistence of species distributions and hitherto unsuspected sensitivity to physical and chemical gradients. Forest composition and spatial structure retain a distinctive industrial character even 120years after abandonment. [Copyright &y& Elsevier]