Black carbon and charcoal records of fire and human land use over the past 1300 years at the Tongguan Kiln archaeological site, China

Abstract

To examine fire patterns and landscape evolution in the Xiangjiang River Basin over the past 1300 years, high-resolution charcoal and black carbon (BC, char and soot) records from the Tongguan Kiln archaeological site of historical ceramic production have been analyzed in combination with robust Optically Stimulated Luminescence (OSL) and accelerator mass spectrometry radiocarbon (AMS14C) dating, archaeological documents, and paleo-environmental proxies (i.e., magnetic susceptibility, total organic carbon, XRF-derived elemental data, etc.).Throughout history, charcoal and BC have recorded changes in regional land use at the Tongguan Kiln site. Peaks in char and macro-charcoal contents indicate that local smoldering fire occurrences were typical with large amount of fuel used for kilns between 1300 and 1100 years B.P. under wet climate conditions. These peaks coincided with the size of the Tongguan Kiln archaeological site, which led to reduction of forest cover from nearby mountains and activated soil erosion. Subsequently, the frequency of fire activity declined to a very low level between 1100 and 600 years B.P., coupling with the decline of the Tongguan Kiln, and with a warm period in the study region. Over the past 600 years, with sharp growth in population, regional fires increased to an unprecedented scale for land reclamation for dry crop cultivation during a cold period, which in turn resulted in further environmental deterioration.In summary, shifts of fire patterns in the study site over the past 1300 years have been closely related to (1) climate variation; (2) the mode of human land use; and (3) vegetation type and fuel combustion efficiency. There was an interactive, complex relationship between these factors in the Xiangjiang River Basin, and these results suggest that the intensity and pattern of human land use could have further impacts on fire patterns and landscape evolution in response to climatic change of the East Asian Monsoon, in the past as well as in the future.