The dendrochronology analysis in the study found that fairly large patches of high-severity fire were relatively common on the North Rim of the Grand Canyon. In dry mixed-conifer forests, historically, high-severity fire years were significantly drier than normal based on reconstructed PDSI, while years of low-severity fire were only slightly, though not significantly, drier than normal. They also found that for mixed-conifer ecosystems, prior wet years (typically needed to build up fuels in drier SW forests) were not necessary for severe fire to occur. Finally, spikes in regeneration of aspen often correspond to years where high-severity fire was common across the greater landscape.

High-severity fire was common in mixed-conifer forests, historically, however, changes in species composition and density due to fire suppression over the last century has changed how fire burns on these landscapes. Maintaining heterogeneity may provide resiliency against future climate change.