Climate driving factors of winter-spring wildfires in the Northeast and Southwest forest zones of China

Abstract

Regional climate controls on wildfires in China remain complex due to high spatial heterogeneity and strict suppression policies. This study aims to objectively identify coherent high-activity wildfire regions in China and clarify the climatic pathways regulating wildfire activity during the fire season. We applied an optimized clustering approach to MCD64A1 burned area data (2001–2024) to delineate fire regimes, and used Pearson and partial correlations to analyze regional climate-fire relationships. Two representative high-activity wildfire regions were identified: the Northeast fire regime area (NFR) and the Southwest fire regime area (SFR). Burned area peaks in both regions during February–April, when soil moisture (SM) deficit acts as a proximal control. However, the climatic drivers regulating SM differ between regions. In the NFR, SM is associated with both snow cover and temperature, both governed by February–March Arctic Oscillation (AO) conditions. SM in the SFR is negatively related to temperature, which is positively associated with February–March El Niño conditions. Winter-spring wildfires in the NFR are governed by a cryosphere–temperature pathway while in the SFR are dominated by a thermally driven pathway. These distinct climate-fire linkages emphasize the importance of region-specific wildfire research under strict fire suppression policies.