Fire history and its forcing in Northeastern Asia boreal forests

Abstract

Fire is a principal disturbance agent in Northeastern Asia forests with the highest fire radiative power globally. The limitation of the wide network of sites with long reconstructed fire histories restricts our understanding of factors forcing regional fire dynamics. We aggregated 30 fire scars-based fire chronologies in Northeastern Asia to create a composite region chronology from 1701 to 2010. We assessed the correlation between solar activity, drought (as represented by the Self-Calibrated Palmer Drought Severity Index, scPDSI), Arctic Oscillation (AO), and forest fire. Large fires were associated with drought, positive AO, and lower sunspot numbers, as revealed by Superposed epoch analysis. The pathways of solar activity force drought and AO, hence, driving fire activity indicated by structural equation modeling. As Solar Cycle 25 (starting in December 2019 and lasting until about 2030) is projected to be as weak as the Dalton minimum (1795–1820 AD), we expect fire activity to remain high over this period. Our findings provide insights into the extraterrestrial forcing of forest fire activity and its prediction in Northeastern Asia.

Keywords

• Forest fire
• Fire history
• Wildfire
• Solar activity
• Sunspot number
• Northeastern asia