In the Northeastern U.S., acid deposition has been linked to declines in soil pH and calcium availability. Concurrently, atmospheric carbon dioxide levels and nitrogen deposition have increased. My dissertation research focused on understanding the long-term effects of forest liming on carbon and nitrogen cycling in temperate forests. I also studied how different tree species influence soil carbon, nitrogen, and calcium dynamics.
Effects of liming on carbon, nitrogen, and calcium cycling in the Woods Lake Watershed, Adirondack Park, NY
The Adirondack Park Region of New York State has experienced severe soil calcium depletion associated with acid deposition. To mitigate the effects of acid deposition in terrestrial and aquatic ecosystems, calcium carbonate (lime) was applied to two 50 hectare subcatchments within the Woods Lake Watershed in 1989. I studied how the increase in soil pH and exchangeable calcium availability resulting from liming has influenced above- and belowground carbon and nitrogen stocks and fluxes, as well as sorption of dissolved organic matter onto mineral soil surfaces.
Results of this work can be found here:
Tree species and earthworm effects on soil carbon, nitrogen, and calcium distribution in a common garden forest
Many studies have shown that individual tree species are correlated with differences in soil carbon, nitrogen, and base cation cycling in naturally established forests. It remains unclear however, whether interspecific differences are due to the influence of trees on their soils or to inherent soil properties which drive species establishment. I investigated how Norway spruce, red oak, and sugar maple influence soil carbon, nitrogen, and calcium distribution within soils and studied how differences in earthworm abundance among study plots affected organic matter turnover. For details, see:
Melvin, A.M., and Goodale, C.L. 2013. Tree species and earthworm effects on soil nutrient distribution and turnover in a Northeastern U.S. common garden. Canadian Journal of Forest Research 43(2): 180-187