Within and among years atmospheric moisture availability influences wildfire burn severity in the boreal forest

作者：Jack A. Goldman, Marie‐Josée Fortin, Patrick M. A. James · 发表于：Fire Ecology · 年份：2026 · DOI：10.1186/s42408-026-00544-x · 研究领域：Fire effects on ecosystems、Landslides and related hazards、Fire Detection and Safety Systems

Abstract Background Atmospheric moisture can either mitigate or exacerbate burn severity depending on fuel and environmental conditions. However, changes in fuel moisture typically lag behind shifts in atmospheric moisture associated with weather or climate changes. When atmospheric moisture decreases, lagged decreases in fuel moisture can affect fire hazard in two ways: they can increase fuel flammability and wildfire severity in the short term, or alternatively, they can decrease wildfire severity over longer periods by slowing the accumulation of combustible materials. Yet, the temporal scales at which lagged moisture changes most strongly influence burn severity are not well understood. Hence, we investigated how time-lagged moisture availability at both inter- and intra-annual timescales, forest composition, and drought conditions during the burn period contribute to wildfire burn severity across 1025 fires (1986–2024) in Ontario (Canada). Specifically, we quantified the relative effects of daily vapour pressure deficit (VPD), annual climate moisture index (CMI) anomalies, fuel composition, and fire‑season weather using distributed lag generalized additive models and hierarchical partitioning to compare the contributions of moisture at intra-annual lag intervals up to 30 days before fire (VPD) and interannual lag intervals up to 5 years before fire (CMI). Results We found that intra-annual atmospheric dryness and interannual moisture availability jointly regulate burn se...