PROCEEDINGS: Index of Abstracts

ELEMENTAL CYCLING RESPONSE OF AN ADIRONDACK SUBALPINE SPRUCE-FIR FOREST TO ATMOSPHERIC AND ENVIRONMENTAL CHANGE

Andrew J. Friedland and Eric K. Miller

Associate Professor and Research Assistant Professor, respectively, Environmental Studies Program, Dartmouth College, 6182 Steele Hall, Hanover, New Hampshire 03755.

Patterns and trends in forest elemental cycling can become more apparent in the presence of atmospheric perturbations. High-elevation forests of the northeastern United States have received large amounts of atmospheric deposition of pollutants, which have altered natural elemental cycling and retention rates in a variety of ways. This study examined atmospheric deposition of nitrogen, sulfur and base cations, and their interactions in a high-elevation forest on Whiteface Mountain, New York. Eight years of elemental cycling data (1986-1993) have shown that at our main study site (1050-m elevation), atmospheric deposition of N was approximately 16.7 kg N ha^-1 yr^-1, with 32 percent contributed by cloud water. Atmospheric deposition of S was 16.3 kg S ha^-1 yr^-1, with 37 percent contributed by cloud water. Total atmospheric inputs of nitrogen and sulfur to the forest canopy increased by a factor of four and five, respectively, over the elevational range of 600 to 1275 m, largely due to the increased importance of cloud water deposition at high elevations. At 1050-m elevation, analyses of total ecosystem inventories and cycling revealed that nitrogen and potassium are conserved or retained in the ecosystem while sulfur, calcium and magnesium show losses in a relatively undisturbed spruce-fir-birch ecosystem.