Vegetation history and climatic variations during the last 14 ka BP inferred from a pollen record at Daihai Lake, north-central China

A 14 ka vegetation and climate history is reconstructed based on a high-resolution pollen record from an arid to semiarid region in north-central China. Nine major episodes of paleovegetation are reconstructed in the record in response to climate changes: sparse-wood grassland, steppe, sparse-wood grassland, steppe, mixed conifer broad-leaved forest, sparse mixed conifer and broad-leaved forest, conifer forest, conifer forest with some broad-leaved, and steppe. Between 14 and 11.2 ka, mild and dry conditions after the glaciation are revealed, and a three-phased monsoonal oscillation interval (cold-dry, cold-humid, and cool-dry) corresponding with the Younger Dryas has been identified from 11.2 to 10 ka. A warm, humid climate is evident between 10 and 7 ka, when broad-leaved trees were abundant. The East Asian monsoon was enhanced during this period and brought in more precipitation to the study area. After 7 ka, with the weakening of the East Asian monsoon, the climate became less moist, and more arid vegetation developed. Conifer forest was well developed between 4.8 to 3.4 ka but was then replaced by steppe.