A 1000-year record of vegetation change and wildfire from maar lake Erlongwan in northeast China

A high-resolution (∼every 20 y) pollen and charcoal record from Erlongwan maar lake (EML) documents the vegetation history and fire activity of the Long Gang region (northeast China) over the past millennium. The age-depth model is based on 137Cs, 210Pb measurements, and one calibrated 14C-AMS date at the base of the core. For much of the record, vegetation was dominated by a mixed conifer-hardwood forest. Pollen and charcoal concentrations reveal considerable variability during the past 1000 years. Between 980 and 1500 AD both pollen and charcoal reached maximum concentrations (∼1100 AD and 1300 AD respectively). The high pollen concentration was indicative of prevailing moist conditions during the period commonly referred to as the Medieval Climatic Anomaly (MCA). The high concentration of charcoal indicated high frequency and intensity of wildfire during the MCA, probably linked to high biomass productivity and less snow in winter. Between 1500 and 1850 AD both pollen and charcoal concentrations were low, indicative of colder winters with higher snowfall, relative drier summers and less intensive wildfire, coincidence with the cold period commonly known as the Little Ice Age (LIA). During 1900-1950 AD year, the highest relative abundance of Artemisia and the lowest abundance of Pinus together with high concentration of charcoal indicated strong human activity. The pollen data are in broad agreement with a previous study from an adjacent lake, indicating regional rather than localized human impact.