Long-Term History of Vegetation and Fire in Pitch Pine–oak Forests on Cape Cod, Massachusetts

Abstract

Abstract. Human disturbance in northeastern North America over the past four centuries has led to dramatic change in vegetation composition and ecosystem processes, obscuring the influence of climate and edaphic factors on vegetation patterns. We use a paleoecological approach on Cape Cod, Massachusetts, to assess landscape-scale variation in pitch pine-oak vegetation and fire occurrence on the pre-European landscape and to determine changes resulting from European land use. Fossil pollen and charcoal preserved in seven lakes confirm a close link between landform and the pre-European distribution of vegetation. Pine forests, dominated by Pinus rigida, were closely associated with xeric outwash deposits, whereas oak-hardwood forests were associated with landforms having finer grained soils and variable topography. In general, fire was much more abundant on Cape Cod than most other areas in New England, but its occurrence varied geographically at two scales. On the western end of Cape Cod, fires were more prevalent in pine forests (outwash) than in oak-hardwood forests (moraines). In contrast, fires were less common on the narrow and north-south trending eastern Cape, perhaps because of physical limits on fire spread.The most rapid and substantial changes during the past 2000 years were initiated by European settlement, which produced a vegetation mosaic that today is less clearly tied to landform. Quercus and other hardwood trees declined in abundance in the early settlement period in association with land clearance, whereas Pinus has increased, especially during the past century, through natural reforestation and planting of abandoned fields and pastures. An increase in fossil charcoal following European settlement suggests that fire occurrence has risen substantially as a result of forest clearance and other land uses, reaching levels greater than at any time over the past 2000 years. Although fire was undoubtedly used by Native Americans and may have been locally important, we find no clear evidence that humans extensively modified fire regimes or vegetation before European settlement. Instead, climate change over the past several thousand years and European land use over the past 300 years have been the most important agents of change on this landscape.

A coupled geomorphic and ecological model of tidal marsh evolution

“…Perhaps, then, the expansive marshland observed today is a metastable, relict feature that developed under higher sediment supply rates in the past. For example, sedimentation rates in the Chesapeake Bay and Coastal Massachusetts increased 4 to 10 times after European settlement and deforestation (29,30), and marshes of the Plum Island Estuary in Massachusetts were likely restricted to the fringes of an open-water basin until some time after 680 years B.P. (31).…”

Simulation of forest change in the New Jersey Pine Barrens under current and pre-colonial conditions

“…Likewise, our ability to properly assess the veracity of the results of our pre-colonial scenarios is limited due to a lack of objective data sources for the study area. In other areas of New England and the Mid-Atlantic, colonial era land surveys (e.g., Cogbill et al, 2002;Russell, 1981) and palynological studies (Watts, 1979;Russell and Standford, 2000;Russell and Davis, 2001;Parshall et al, 2003) have been used to reconstruct pre-colonial era vegetation regimes. However, the colonial era land survey record for the area of the NJPB has not been carefully investigated and it is unclear whether they will provide sufficient information to resolve the vegetation patterns of the pre-colonial era.…”

Estimating potential forest NPP, biomass and their climatic sensitivity in New England using a dynamic ecosystem model

“…The distribution of these forest types reflects regional climatic conditions: boreal conifers are currently widespread at higher elevations and in northern regions of New England, northern deciduous hardwoods are mainly distributed in the cooler central uplands, and mixed oak-hickory forests are found at lower elevations and more southerly regions. Although the current relationship between climate and New England forests is partly obscured by human activities and ecological succession following land abandonment (e.g., Parshall et al 2003), historical evidence (e.g., Shuman et al 2004) has demonstrated a strong relationship between climate and forest dynamic in New England. To evaluate the effects of historical climate variation on forest NPP and biomass in the study region, we excluded all land-cover types that are currently subject to substantial human use.…”