Extreme fire events are escalating with warmer and drier fire seasons and are projected to increase under future climate scenarios

Such fires pose critical challenges to the resilience of southwestern forests, where anomalously large and homogeneous high-severity patches generated by extreme single-day fire spread events jeopardize post-fire regeneration by reducing seed availability and dispersal in obligate-seeding conifers. Both fire spread and severity are influenced by fire weather, fuels, and topography however, the extent to which the outcomes of extreme events may be mediated by fine-scale variation in landscape factors (for example, vegetation type, fuels treatments) is not well known. To relate patterns of fire spread, burn severity, and landscape factors, we will utilize daily fire progression maps derived from satellite fire detections for fires 400 HA from the last two decades in forested ecoregions of the southwestern united states. Daily fire spread events will be categorized as extreme (top 2.5% of events) and non-extreme (bottom 97.5%). We will further contrast satellite-derived burn severity (composite burn index CBI) and high-severity patch metrics (for example, mean patch size, total core area) to assess landscape patterns generated by extreme fire events. We will then explore how a suite of key environmental covariates including canopy cover, topography, vegetation, hydrology, previous burns, fuel treatments, roads, and fire weather influence fire spread rates and their burn severity outcomes using machine learning models. This work seeks to understand how landscape factors may exacerbate or ameliorate the potential for extreme fire events and their resultant impacts on tree persistence and regeneration potential in increasingly fire-impacted forest types. In addition to furthering scientific research on extreme fire events in the southwestern US, these findings can aid managers in identifying and prioritizing strategies that may reduce the likelihood of extreme fire spread and or undesirable post-fire landscape outcomes. As extreme fire spread andseverity are both predicted to escalate in an increasingly fiery future, understanding how landscape factors may modulate the ecological outcomes of extreme fire events and burn severity is crucial in bolstering the resilience of forest ecosystems and communities alike.