T46 Dendrogeology: Geologic Applications of Tree-Ring Studies

Sunday, 16 October 2005
1:30 PM - 3:30 PM

SUBFOSSIL BALDCYPRESS FORESTS OF THE ATLANTIC COASTAL PLAIN, SOUTHEASTERN USA

Paper number: T46-1
Program: Technical Sessions
Time: 1:30 PM – 1:50 PM

Authors

Abstract

Baldcypress [Taxodium distichum (L.) Rich.] is a long-lived deciduous conifer native to the forested wetlands of the southeastern United States. Tree-ring chronologies developed from this species have been used to reconstruct growing season precipitation amounts for the past 1000 to 1600 years. Baldcypress estimates of past drought have been confirmed in part with historical records, including the descriptions of hunger and heavy mortality suffered at Jamestown Colony, Virginia, during a severe seven-year drought.

Many well-preserved baldcypress logs have recently been recovered from sand quarries near the Lynches and Little Pee Dee Rivers, South Carolina. These “subfossil” cypress logs are solid to pith, are up to two meters in diameter and 30 meters long, and can be cut and finished to a high polish suitable for fine woodworking and scientific analysis. A few radiocarbon dates have been obtained indicating that these subfossil wood deposits range from approximately 22,000 to over 45,000 years old. Some logs contain hundreds of annual growth rings and present an excellent opportunity for the development of millennia-long "floating" tree-ring chronologies during the late Pleistocene. No long, annually-resolved tree-ring chronologies of such great age exist in North America and they would be valuable for the study of Pleistocene climatic changes, investigating long-term variation in atmospheric radiocarbon levels and the global carbon cycle, and will help document the sweeping environmental changes that have taken place on the South Carolina Coastal Plain in the past 50,000 years.