Holocene wildfire activity and climate change in the Zoige Basin, eastern Tibetan Plateau, China

Understanding paleoenvironment changes and their driving mechanisms are crucial for predicting and responding to future climate change. Through extensive field investigations, a complete Holocene sedimentary profile has been discovered in the Zoige Basin of the eastern Tibetan Plateau. The history of Holocene wildfire activities and climate change in this region was reconstructed using various paleoclimate proxies, including charcoal, magnetic susceptibility, and total organic carbon. This study also elucidated the relationship between Holocene paleoenvironmental conditions and wildfire activities. The results indicated that during the Holocene, the wildfire activities in the Zoige Basin were primarily regional, with local fires mainly involving woody plants and regional fires dominated by herbaceous plant burning. In the early Holocene, before 8.5 ka, despite a temperature increase, the climate in the Zoige Basin remained dry and cold. During this period, an aeolian sand layer was deposited, and the limited plant biomass restricted wildfire occurrence, resulting in the low frequencies of both local and regional fires. During the middle Holocene (8.5–3.1 ka), the warm and moist climate driven by the East Asian summer monsoon led to the development of a paleosol layer in the Zoige Basin. The increased temperature and precipitation enhanced the plant biomass, and frequent regional and local wildfire activities were observed. In the Late-Holocene, after 3.1 ka, as the climate cooled and dried, a modern soil layer formed and wildfire activities decreased. The reduction in plant biomass likely contributed to the decline in regional wildfires, whereas the intensification of local fires may have been influenced by human activities. The results enhanced our understanding of wildfire history and climate evolution in the Zoige Basin.