A 1000-year record of centennial-scale cyclical vegetation change from Maar Lake Sanjiaolongwan in northeastern China

To examine possible relationships between regional changes in vegetation and climate and fluctuations in solar activity, we obtained a high-resolution 1000-year pollen record from the Sanjiaolongwan Maar Lake (SJML) in northeastern China. An age model was established using analyses of Pb-210, Cs-137 and AMS C-14. The pollen assemblages indicate that during the last millennium the vegetation of the study area was temperate coniferous and deciduous broadleaved mixed forest. Although Pinus is the most abundant pollen type in the record, various lines of evidence suggest that it is not especially temperature-sensitive. However, the analysis of the changes in pollen assemblages over the past 1000 years, and a comparison with pollen records from other lakes in the region, indicate that the Quercus frequencies can be used as a relatively sensitive temperature index for the study area. Several notable cold periods, with lower Quercus frequencies, occurred at approximately 1200 AD, 1410 AD, 1580 AD, 1770 AD and 1870 AD. These centennial-scale cold periods basically correspond to major minima in solar activity, suggesting that variations in solar activity may have been an important driver of climate and vegetation change in the study area during the last millennium.