Fire severity rising despite lower frequency in the Southwestern U.S.

A smoke plume billows from a wildfire. Credit: Kaibab National Forest

Wildfires in the southwestern U.S. are becoming more severe, but are they burning more frequently than they did in the past? A recent study compared fire patterns from 1700-1880 with modern data from 1985-2020 using tree-ring records, satellite imagery, and field data. The tree rings, which preserve scars from past fires, reveal that fires used to occur every 11 years on average, while today they happen much less frequently. However, the study found that while fires today are less frequent, they are burning with much greater intensity, with nearly half of modern fires causing high tree mortality. Historically, trees survived many low-severity fires, but fire suppression has led to larger, more destructive fires. The study, published in Communications Earth & Environment, suggests that using controlled burns and managing wildfires could help restore historical fire patterns and improve forest resilience.