RELEASE OF ALUMINUM FOLLOWING WHOLE-TREE HARVESTING AT THE HUBBARD-BROOK-EXPERIMENTAL-FOREST, NEW-HAMPSHIRE

From fall, 1983, through spring, 1984, an experimental watershed at the Hubbard Brook Experimental Forest in New Hampshire was commercially whole-tree harvested. Stream chemistry was monitored along an elevational gradient for approximately 1 yr prior to and 2 yr following the treatment in both the experimental watershed and an adjacent reference watershed. Whole-tree harvesting initially resulted in a large increase in stream NO//3** minus and basic cation (CA**2** plus , Mg**2** plus , Na** plus , and K** plus ) concentrations and a decrease in stream sulfate concentrations. A decrease in pH and increase in Al concentrations followed. Elevational trends in stream chemistry were qualitatively similar before and after the cut, although the absolute concentrations of solutes changed markedly. These responses are discussed in the paper.