How Does Acidic Deposition and Liming Affect Aboveground Wood Nutrition in a Young Hardwood Forest?.

There is much literature that supports the idea that atmospheric nitrogen deposition potentially affects macro- and micro-nutrient dynamics; this research examines the impact of simulated acidic deposition on stem wood nutrition in a young, hardwood forest in West Virginia. The Long-term Soil Productivity (LTSP) site in the Fernow Experimental Forest served as the study site; it was initiated in 1996 with three treatments that were whole-tree harvested and left to naturally regenerate: one received no fertilizer amendments (WT), another received ammonium sulfate at two times the annual ambient rate (WT+N), and the last received ammonium sulfate at the same rate plus dolomitic lime additions that were two times the rate of calcium and magnesium export to local stream waters (WT+N+CA). The lime treatment was implemented to observe its ameliorative effects on increased rates of acidic deposition. Destructive sampling for wood tissue was carried out on the three treatments in 2008; wood was analyzed for N, S, P, K, Ca, Mg, Mn, Fe, Zn, Cu, and B concentrations in five of the most abundant species including yellow-poplar, red maple, sweet birch, black cherry, and pin cherry; northern red oak was also examined. Element concentrations were applied to estimates of aboveground biomass to compare nutrient content between treatments. Results suggest slightly altered dynamics of K, Ca, Mn, and Zn in the WT+N and WT+N+CA treatments compared to the WT treatment. Highest concentrations of all nutrients were found in yellow-poplar, northern red oak, and red maple wood tissue, with the exception of Zn, which had highest concentrations in sweet birch. Our results show a small number of differences in wood nutrient concentrations and no differences in aboveground wood biomass between treatments, indicating the resistance of this forest to the effects of acidic deposition. However, the data suggest signs of nutrient stress in the WT+N treatment due to lower wood concentrations of Ca and P compared to the WT and WT+N+CA treatment. Ammonium sulfate additions in this forest therefore have the potential to alter soil and wood chemistry at a young age without affecting aboveground wood biomass production.