Effect of whole-tree harvesting on the sulfur dynamics of a forest soil

Sulfur constituents in the soil at the Hubbard Brook Experimental Forest are dominated by C-bonded S and ester-sulfate with smaller concentrations of adsorbed sulfate and ZnHCl-reducible S forms. The relative proportions of these constituents are similar to those found in other Spodosols. Two years after a whole-tree harvest of Watershed 5 there was a significant increase in adsorbed sulfate in the E and Bh horizons, while organic S pools remained relatively constant except for some change in ester-sulfate pools. This increase in sulfate in these horizons is consistent with patterns of soil solution and stream chemistry, which indicate increased sulfate adsorption due to acidification following mineralization of N, nitrification, and nitric acid leaching. Organic S ranged 0.7 to 9.5 μmol S L^-1 in stream and soil solutions. When this organic S is transported through the soil and deposited in the B horizon, it may serve as a large, stable pool of soil S, less subject to change than that of adsorbed sulfate. -from Authors