We are very proud of Stephanie Mueller on the publication of her thesis research, and her first first-author paper! Having her expertise at CFRI increases our spatial analytical capacity.
Over the last several decades in forest and woodland ecosystems of the southwestern United States, wildfire size and severity have increased. These systems are now more vulnerable to type conversions, invasive species, and other disturbances. A combination of land use history and climate change is widely thought to be contributing to the changing fire regimes. Mueller and her co-authors examined climate-fire relationships in forest and woodland ecosystems from 1984 to 2015 in Arizona and New Mexico using an expanded satellite-derived burn severity dataset, and climate variables including temperature, precipitation, and vapor pressure deficit (VPD). Results suggest that increasing temperature and VPD and decreasing precipitation were associated with increasing area burned regionally, and that area burned at high severity had the strongest relationships with climate metrics. The relationship between climate and fire activity in the Southwest appears to be strengthening since 2000. VPD-fire correlations were consistently as strong as, or stronger than, temperature or precipitation variables alone, both regionally and at the scale of the individual fire. Notably, at the scale of the individual fire, temperature and precipitation were not significant predictors of fire activity. The results support the use of VPD as a more integrative climate metric to forecast fire activity. The link between increasing aridity and increasing wildfire activity suggests a future with more fire in Southwest forests and woodlands with projected warming, underscoring the urgency of restoration in dry forests to reduce the likelihood of uncharacteristic, large high-severity fires.