A comparison of vegetative cover and tree community structure in three forested Adirondack watersheds

Abstract

The Integrated Lake–Watershed Acidification Study (ILWAS) was conducted using three forested watersheds (Panther, Sagamore, and Woods) in the central Adirondack Park of New York State. By comparing the biogeochemical behavior of these watersheds, the ILWAS investigators hoped to elucidate the major ecosystem parameters controlling the fate of strong acids introduced from the atmosphere to lake–watershed systems. The ILWAS vegetation research program was designed to compare the quantitative patterns of forest structure in these midelevation watersheds. Results showed that the ILWAS catchments contain closely related variants of the northern hardwood – spruce – fir complex of the Adirondack region. The dominant tree species in these watersheds are beech (Fagusgrandifolia Ehrh.), red spruce (Picearubens Sarg.), sugar maple (Acersaccharum Marsh.), red maple (Acerrubrum L.), and yellow birch (Betulaalleghaniensis Britt.). On an areal basis, the watersheds contain 57–88% hardwood cover type and 5–29% spruce–fir cover type. Mean live basal area values range from 22 to 30 m² ha⁻¹ between catchments, while standing dead basal area values range from 4 to 8 m² ha⁻¹. Mean live stem densities range from 1400 to 1700 stems ha⁻¹. Mean aboveground biomass projections for the tree stratum in the three watersheds range from 143 to 199 Mt ha⁻¹, while estimated aboveground annual biomass increments range from 4.1 to 5.3% of standing biomass.