Climate stability shaped fire regimes over the past ~1400 years in northeastern China

Paleofire studies have provided critical long-term data on past fire dynamics. However, previous research has predominantly focused on the influence of climatic factors on paleofires, paying little attention to the role of climatic stability. Here, we use a precisely established varve chronology to reconstruct a ~1400-year high-resolution fire history from charcoal and soot records in the sediments of Sihailongwan Maar Lake, a representative forested region of northeastern China. We further investigate the role of climatic stability in controlling fire frequency and size. We show that during periods of climatic instability (ca. 900–1100 CE, ca. 1250–1500 CE, ca. 1600–1800 CE), fire frequency markedly increased, while the individual fires were generally small. In contrast, during periods of climatic stability (ca. 710–900 CE, ca. 1100–1250 CE, ca. 1500–1600 CE), fires occurred less frequently but were larger in size. Climatic stability regulated fire dynamics by affecting fuel accumulation and moisture content through climatic whiplash (extreme wet-dry oscillations). Against the recent backdrop of rapid global warming and regional anthropogenic fire suppression, the potential risk of fires may increase dramatically. Our results support a policy of shifting fire suppression policies towards a “healthy forest” management system to better balance ecological conservation and fire management needs.