Ecological benefits and risks arising from liming sugar maple dominated forests in northeastern North America

Liming, the application of carbonate materials (e.g., CaCO3, CaMg(CO3)2) to soils and surface waters, has been used extensively in Europe, and to a lesser extent in Canada and the United States, to mitigate the effects of acid deposition on forest and aquatic ecosystems. This literature review was conducted to assess the effects of liming on ecologically and economically important sugar maple dominated ecosystems of northeastern North America, where it is increasingly used to treat sugar maple dieback. Potential direct and indirect effects were considered to determine whether the use of liming to revitalize these forests could negatively affect other ecological parameters, including those in adjacent aquatic habitats. Based on current scientific literature, it is not anticipated that liming at rates of 1–3 t ha−1 would have major detrimental effects on these ecosystems. However, liming could have negative effects on northern hardwood forests with regard to earthworm invasions. The choice of liming as a mitigation tool should be made not only after weighing the potentially negative effects against the benefits of restoring sugar maple dominated stands in poorly buffered soils, but also after considering ecological components that could be lost or never recovered if an acidified forest ecosystem is not limed.