Integrated reconstruction of fire history and climatic changes in Northwest China since mid-late Holocene

A total of 28 records of charcoal and black carbon were used to reconstruct the evolution and driving mechanism of paleofire events in Northwest China in the past 8 ka. Combined with paleovegetation, paleoclimate, and historical records, relationship among paleofire activity, climate change, and human impact was analyzed. Results show that during the middle and late Holocene, fire history in Northwest China can be divided into four stages: (1) the fluctuation stage of fire activity (8～6 kaBP), paleofire events occurred frequently and were mainly affected by climate change; (2) the stable stage of fire activity (6～4 kaBP), when the climate tended to be warm and humid, vegetation developed and stored a certain amount of combustible material; (3) the rapid rise stage of fire activity (4～2 kaBP), human activities became the main influencing factor for fire events, and the frequency of fire activities showed a rising trend; (4) the stage of large-scale fire activity (2～0 kaBP), the climate changed from wet-cold to dry-cold, biomass was dry and flammable, agriculture developed rapidly, dynasty changed and frequent wars occurred, and the fire activity was exceptionally intense.