Wetland forests of Tompkins County, New York.

Data on woody vegetation were subjected to cluster analysis, resulting in 4 groups of samples. Ordination by reciprocal averaging revealed that 2 of these groups were distinctive vegetation types (swamps with Tsuga canadensis, Acer rubrum and Betula lutea, and stands of Acer saccharinum and Fraxinus spp.); another group comprised 2 vegetation types (Populus deltoides-Platanus occidentalis-Ulmus americana floodplain stands and Acer saccharum-Fraxinus americana stands). The last group, a collection of varied successional and long-lived Swamp Shrub communities, is too heterogeneous to be considered a vegetation type. Seasonality of water levels and soil texture constitute the major environmental gradients separating these swamp vegetation types. Herbaceous species do not appear to be grouped into the same vegetation types as the woody species. -from Author