Late Quaternary fire and vegetation history inferred from the Xifeng loess-paleosol sequence of the Chinese Loess Plateau

The focus of this paper is to reconstruct late Quaternary wildfire and vegetation history in Chinese Loess Plateau (CLP) region, and to determine the interrelationships between wildfire, climate, and vegetation. To achieve this aim, we analyzed the black carbon concentration and pollen assemblages within an interval correlated with Marine Isotope Stage (MIS) 5 (equivalent to paleosol S1) to MIS 4-2 (equivalent to Loess L1) in the Xifeng section of the CLP. Findings show that during the MIS 5-2 intervals, changes in precipitation and temperature were essentially synchronous on the CLP, and changes in biomass reflected by total organic carbon content and pollen assemblages were determined mainly by the climatic conditions. Wildfire was controlled mainly by fuel humidity and vegetation type, which influenced by precipitation; however, there was no significant relationship between wildfire occurrence and temperature or the amount of combustible plant material. During the MIS 5 interval, the climate was warmer and wetter than today, while during the MIS 3 interval (Loess L1SL1) it was similar to today; however, during the MIS 2 (L1LL1) and MIS 4 (L1LL2) the climate was cooler and drier. Fires were less frequent during the MIS 5 interval compared to the MIS 3, and fires during the MIS 2 and MIS 4 were more frequent than the MIS 3. Results suggested that if the climate on the CLP became warmer and wetter in the future, natural fires would not necessarily occur more frequently and intensively. However, if climate evolved towards cooler and drier conditions, natural fires may be more likely to occur.