摘要
A complex history of the Late Pleistocene vegetation and environmental changes for the northern part of the deciduous forest is revealed in an exceptionally well dated pollen diagram from Dongganchi in Beijing area. In 15?800- 14?700 a B.P., the arbors and aquatic plants were sparse, and the climate was cold and dry. In 14 700-13?400 a B.P., forest growth was limited, it was dominated by conifers, presumably in responded to a cooling climate. Aquatic plants became abundant. During 13?400 to 12?600 a B.P., there was a widespread development of coniferous and broad leaved mixed forest, aquatic plants decreased which corresponded to climate gradually becoming warming and dry. In 12?600-11?400 a B.P., there was alternation of coniferous and broad leaved mixed forest, so were aquatic plants. From 11?400 to 9?600 a B.P., the decreasing of trees and increasing of herbs and shrubs suggested an opening up of the vegetation in responded to cooling, probably corresponded to Younger Dryas from 10?600 to 10?300 a B.P. About 9600-7270 a B.P., the climate changed from cooler and dry to warmer and humid. About 7270-3390 a B.P., the coniferous and the broad leaved mixed forest increased, it was in responding to the “climatic optimum". About 3390-1000 a B.P., climate became cooler and dry. After 1000 a B.P., there was a severe fluctuation, indicating the temperature drop and the environmental deterioration.
A complex history of the Late Pleistocene vegetation and environmental changes for the northern part of the deciduous forest is revealed in an exceptionally well dated pollen diagram from Dongganchi in Beijing area. In 15?800- 14?700 a B.P., the arbors and aquatic plants were sparse, and the climate was cold and dry. In 14 700-13?400 a B.P., forest growth was limited, it was dominated by conifers, presumably in responded to a cooling climate. Aquatic plants became abundant. During 13?400 to 12?600 a B.P., there was a widespread development of coniferous and broad leaved mixed forest, aquatic plants decreased which corresponded to climate gradually becoming warming and dry. In 12?600-11?400 a B.P., there was alternation of coniferous and broad leaved mixed forest, so were aquatic plants. From 11?400 to 9?600 a B.P., the decreasing of trees and increasing of herbs and shrubs suggested an opening up of the vegetation in responded to cooling, probably corresponded to Younger Dryas from 10?600 to 10?300 a B.P. About 9600-7270 a B.P., the climate changed from cooler and dry to warmer and humid. About 7270-3390 a B.P., the coniferous and the broad leaved mixed forest increased, it was in responding to the “climatic optimum'. About 3390-1000 a B.P., climate became cooler and dry. After 1000 a B.P., there was a severe fluctuation, indicating the temperature drop and the environmental deterioration.
