Anthropogenic ties to late-successional structure and composition in four New England hemlock stands

The pace and magnitude of long-term change in the forests of eastern North America is poorly understood. The current study examines the developmental history of primary Tsuga canadensis stands in central Massachusetts from be fore European settlement to the present. Through an integrated reconstructi ve approach employing stand-level pollen stratigraphies, tree ring chronolo gies, and long-term archival records, we show how the characteristic struct ure and composition of old-growth forests in southern New England developed in four stands through a history of anthropogenic and natural disturbance, rather than through the gradual process of autogenic succession. Forest co mposition during presettlement times was distinct at each site and included a variety of successional stages ranging from late-successional northern h ardwood-Tsuga assemblages to assemblages dominated by early successional to mid-successional taxa such as Castanea, Quercus, and Pinus. Anthropogenic disturbance during the 18th and 19th centuries resulted in novel assemblage s dominated by Castanea or Betula. Composition at the four sites converged on the current assemblage dominated by large, late-successional Tsuga, in r esponse to altered patterns of disturbance in the 20th century. The age of the dominant trees (100-200 yr) and apparent stability of the current fores ts masks the extent to which their origin is a product of the cultural land scape and is in no way representative of pre-European forests at these site s.