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

Liming, the application of carbonate materials (e.g., CaC[O.sub.3], CaMg[(C[O.sub.3]).sub.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.sup.-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. Key words: acidification, acid rain, mitigation, liming, sugar maple, restoration, ecosystem, forest, aquatic habitat. Le chaulage, l'application de materiel carbonate (par exemple: CaC[O.sub.3], CaMg[(C[O.sub.3]).sub.2]) sur les sols et les eaux de surface, a ete largement utilise en Europe, et dans une moindre mesure au Canada et aux Etats-Unis, afin d'attenuer les effets des depots acides sur les ecosystemes forestiers et aquatiques. Cette revue de litterature a ete effectuee afin d'evaluer les effets du chaulage sur les ecosystemes forestiers domines par l'erable a sucre, qui sont importants au plan ecologique et economique dans le nord-est de l'Amerique du Nord, dans lesquels il est de plus en plus utilise pour traiter le deperissement de l'erable a sucre. Les effets potentiels directs et indirects ont ete consideres afin de determiner si l'utilisation du chaulage pour revitaliser ces forets pourrait avoir des effets negatifs sur d'autres composantes ecologiques, incluant celles des habitats aquatiques situes a proximite. Sur la base de la litterature scientifique actuelle, il n'est pas prevu que le chaulage a des taux de 1 a 3 t [ha.sup.- 1] ait des effets nefastes importants sur ces ecosystemes. Cependant, les erablieres chaulees pourraient etre sujettes aux effets negatifs lies a l'invasion de vers de terre. La decision finale d'utiliser le chaulage comme outil de mitigation doit non seulement tenir compte des effets potentiellement positifs et negatifs de ce traitement dans les erablieres situees sur des sols a faible pouvoir tampon, mais aussi des composantes ecologiques qui pourraient etre perdues ou ne jamais etre recuperees si un ecosysteme forestier acidifie n'est pas chaule. Mots-cles: acidification, pluie acide, mitigation, chaulage, erable a sucre, restauration, foret, habitat aquatique, ecosysteme.
1. Acid deposition and the need for liming Acid deposition (acid rain) emerged as one of the most publicly visible environmental issues during the 1970s and 1980s (Driscoll et al. [...]