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Acid deposition interactions with a regenerating southern Appalachian forest canopy at the Coweeta Hydrologic Laboratory

Thesis/Dissertation ·
OSTI ID:7188965
Incident precipitation, throughfall, and stemflow were collected during twenty storm events to examine the importance of factors potentially determining net canopy fluxes, and to quantify canopy exchange and dry deposition rates in a regenerating southern Appalachian forest. Net throughfall fluxes showed consistent canopy effects on rainfall chemistry, with SO/sub 4//sup 2 -/, PO/sub 4//sup 3 -/, Cl/sup -/, K/sup +/, Ca/sup 2 +/, and Mg/sup 2 +/ added to rainfall by foliage, and absorption of NO/sub 3//sup -/-N, and H/sup +/ ions from precipitation. Storm characteristics accounted for the largest portion of the variability in growing seasons net throughfall fluxes, suggesting that canopy exchange was the major mechanism of throughfall transfer. Stemflow fluxes increased canopy exchange rates of SO/sub 4//sup 2 -/, PO/sub 4//sup 3 -/, Cl/sup -/, K/sup +/, and Mg/sup 2 +/ by greater than 20% when added to net throughfall fluxes in a regression model of total below-canopy element fluxes. Cation leaching fluxes were highly variable over small spatial scales but could be explained largely by heterogeneity in canopy cover and hydrogen ion uptake from precipitation.
Research Organization:
Emory Univ., Atlanta, GA (USA)
OSTI ID:
7188965
Country of Publication:
United States
Language:
English