Postglacial Montane Vegetational History Around Balsam Lake, Catskill Mountains, New York

Abstract

IBE, R. A.(Dept. Anthropology, Stony Brook (SUNY), Stony Brook, NY 11794). Postglacial montane vegetational history around Balsam Lake, Catskill Mountains, New York. Bull. Torrey Bot. Club 112:176-186. 1985-A history of postglacial local and extralocal montane vegetation is preserved in sediments recovered from Balsam Lake, a small lake (ca. 2 ha) in the western Catskill Mountains, New York, and a radiocarbon-dated sequence is provided as time control. Early postglacial pollen assemblage zones at Balsam Lake are similar to pollen assemblage zones recognized elsewhere in New York and in New England. Abies and Picea forests became dominant in the Balsam Lake area around 12,000 Y BP and were replaced largely by Pinus which reached its highest development by 9,000 Y BP. By 7,000 Y BP Pinus was succeeded by Tsuga, Betula, Fagus, and Acer. Fossil pollen from these genera are compatible with the local and extralocal present-day vegetational community structure surrounding Balsam Lake. Except for the dramatic Tsuga decline recorded around 4430 Y BP, the pollen record at Balsam Lake from the mid-holocene to the present registers only slight changes in pollen frequencies for most major trees. These changes include a partial recovery of Tsuga and the appearance of Castanea pollen by 2,500 Y BP. Some regional components of the pollen rain are preserved in the Balsam Lake sediments as weaker pollen signals from surrounding lowland positions. These signals are broadcast mainly from prolific pollen producers, such as Quercus, and they may represent larger vegetational events occurring at lower elevations (below 500m). Poor pollen producers (e.g., Carya,Juglans) are not strongly represented in the Balsam Lake pollen record. Evidence indicates that the fossil pollen record is influenced largely by site elevation and surface area of the pollen catchment site.