The question of what is “natural” and its consequences for conservation and ecosystem management in New England have long been debated. For example, the prevalence of nut-bearing trees, including oak, hickory, and chestnut, has been interpreted as being promoted by Native American activities. Likewise, the origins of pine-barren and openland plant communities have been attributed to land uses of Native American and/or European settlers. Various retrospective approaches, such as historical accounts, witness-tree data, tree-ring records, and paleoecological studies, have been used to shed light on such questions, but the impacts of humans on past and present ecosystems remain poorly understood. We take advantage of a growing database of lake-sediment and archaeological records to explore these questions, gaining insight from emerging information about pre-settlement environmental changes, vegetation patterns, fire history, and human activities.
Pollen data from across New England show clearly that herbaceous taxa were rare prior to European settlement, with major increases in their abundance occurring as the region was deforested during the seventeenth and eighteenth centuries. Lake-sediment records indicate complex ecological responses to century-scale climatic variability during the Holocene, including changes in fire activity and abrupt declines of eastern hemlock and oak at different times in different part of the region. For example, the well-known decline of hemlock in inland New England 5500 years ago is paralleled by a coincident decline of oak at sites on Cape Cod and the adjacent islands. Pollen records in the southwestern part of the region, however, reveal a similar decline in oak 4000 years ago. Overall, the Holocene is characterized by ecological instability, including shifts as dramatic as those associated with European settlement, making it difficult to define “natural” conditions. Comparison of archaeological data from southern New England with the paleoclimatic and paleoecological records indicates that human settlement patterns were driven by environmental and ecological variability. Taken together, these lines of evidence suggest that Native Americans had only limited effects on New England ecosystems, while European settlement had major and long-lasting impacts. Thus, some plant communities of critical conservation concern, and the processes needed to maintain them, are not necessarily “natural,” nor were they controlled by the indigenous people of the region.