Qichao Yao

Background: Regional climate controls on wildfires in China remain complex due to high spatial heterogeneity and strict suppression policies. Aims: 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. Methods: 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. Key results: 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. Conclusions: Winter-spring wildfires in the NFR are governed by a cryosphere–temperature pathway while in the SFR are dominated by a thermally driven pathway. Implications: These distinct climate-fire linkages emphasize the importance of region-specific wildfire research under strict fire suppression policies.

Fire regulates the carbon, water and nutrient cycles, especially in regions with distinct wet and dry seasons. The dramatic vegetation response to climatic factors complicates fire preconditions in Eurasian drylands, leaving our understanding of climate-fuel-fire patterns limited. Here we identify eight pyromes with unique combinations of fire characteristics of size, expansion, frequency and duration. We find these pyromes are geographically contiguous and exhibit varied response to climate, fuel load, fuel flammability and human activities. Fuel load is closely related to fast-spreading fires in Eurasian Steppe, which mostly belongs to the large-fast-frequent-long (LFFL) and medium-fast-intermediate-short (MFIS) pyromes. There, antecedent fine fuel accumulation during the growing season dries out in the subsequent dry season, is ignited by human activity and spreads rapidly. High-latitude regions are dominated by slow-spreading but long-lasting fires (large-slow-rare-long (LSRL) and medium-slow-intermediate-long (MSIL) pyromes), where changes in fuel flammability due to long-term climate stress determine fire extent. These findings provide initial guidance of which controls should be considered for improving predictions of fire activity and fire risk assessment across Eurasian drylands.

Identification of effects that climate teleconnections, such as El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North Atlantic Oscillation (NAO), have on wildfires is difficult because of short and incomplete records in many areas of the world. We developed the first multicentury wildfire chronologies for northeast China from fire‐scarred trees. Regional wildfires occurred every 7 years from the 1700s to 1947, after which fire suppression policies were implemented. Regional wildfires occurred predominately during drought years and were associated with positive phases of ENSO and PDO and negative NAO. Twentieth century meteorological records show that this contingent combination of +ENSO/+PDO/−NAO is linked to low humidity, low precipitation, and high temperature during or before late spring fire seasons. Climate and wildfires in northeast China may be predictable based on teleconnection phases, although future wildfires may be more severe due to effects of climate change and the legacy of fire suppression.