Holocene Development of a Forested Wetland in Central Massachusetts

• Format: Dataset
• Language: unknown
• Published: Harvard Forest324 North Main StreetPetershamMA01366USA(978) 724-3302(978) 724-3595http://harvardforest.fas.harvard.edu 2003
• Subjects: fire; forest history; pollen analysis; vegetation dynamics; Prospect Hill; Tundra
• Online Access: http://hdl.handle.net/10255/dryad.20715; http://metacat.lternet.edu/knb/metacat/knb-lter-hfr.100.9/xml

The post-glacial history of two adjacent sites in the Harvard Forest, a 10-ha swamp (Black Gum Swamp) and a 0.006-ha hollow (Hemlock Hollow) in a Tsuga canadensis forest were investigated using pollen analysis. The sites were selected in order to contrast the regional vegetation history revealed from the swamp sediments with the local history of the Tsuga forest reconstructed from the Hollow sediments. Specific objectives were (1) to document the natural and anthropogenic disturbance history, (2) to examine the long-term vegetation dynamics of the two sites resulting from environmental change, species migration, and disturbance, especially with respect to Tsuga, and (3) to contrast the pre-and post-settlement vegetation and environments. The Swamp and Hollow cores contain continuous sediment records covering the past 12,300 and 9500 yr, respectively. Regional vegetation changes are delimited in six pollen zones: I, Herb zone, (12500 – 11800 yr BP); II, Picea zone (11800 –9350 yr BP) III, Pinus-Quercus zone (9350-8350 yr BP); IV, Tsuga-northern hardwoods zone (8350-1750 yr BP); V, Tsuga-Castanea-hardwoods zone (1750-200 yr BP); and VI, Post-settlement zone (200 yr BP-present). No disturbances are detected in the periods of tundra or boreal vegetation from 12500 to 8350 yr BP. Since 8350 yr BP three distinct disturbance processes are detectable: (1) fires recorded in discrete charcoal horizons, (2) the apparent pathogenic decline of Tsuga (4700-3500 yr BP) and the blight of Castanea (~1915 A.D.), and (3) post-settlement forest cutting, burning, land clearance an cultivation (1750 A.D. to present).