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Lead Distribution and Fluxes in a High‐Elevation Forest in Northern Vermont
Author(s) -
Friedland A. J.,
Johnson A. H.
Publication year - 1985
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1985.00472425001400030006x
Subject(s) - forest floor , environmental science , leaching (pedology) , soil horizon , soil water , bark (sound) , biomass (ecology) , hydrology (agriculture) , forestry , geology , ecology , soil science , biology , geography , geotechnical engineering
High‐elevation forests receive large amounts of atmospheric lead (Pb) and accumulate it in the forest floor. In order to determine Pb partitioning in a montane, coniferous forest, we analyzed forest floor and mineral soil (Haplorthods and Fragiorthods), and vegetation parts (leaves, twigs, bark, wood) for their Pb content. Soil and stream water were sampled to estimate Pb flux. Mean Pb concentration in trees, in mg kg −1 , was root bark (33.0), twigs (28.3), bark (23.0) > root wood (10.4) > foliage (3). wood (3). Total Pb in above‐ground biomass (trees + shrubs + herbs) was 0.89 kg ha −1 . Lead in the organic horizon (forest floor) was 20 kg ha −1 while Pb in the mineral horizon (E + B) was 63 kg ha −1 . Monitoring of soil water for one year yielded volume‐weighted mean Pb concentrations of 3.7, 1.8, 1.1, and 1.0 µ g L −1 at 3‐, 12‐, 25‐, and 40‐cm depth, respectively. Stream Pb concentration averaged 0.6 µ g L −1 . We estimated annual Pb input of > 700 g ha −1 yr −1 . Estimated output from the forest in stream water was < 12 g ha −1 yr −1 . Annual accumulation in the forest floor is approximately 3% of the current forest floor Pb amount. At current accumulation rates, forest floor Pb amount will double in 30 to 40 yr. At current leaching rates, mean residence time of Pb in the forest floor is approximately 500 yr. The ratio of Pb input to output for the forest is 60:1.