Fire was a keystone process in dry conifer forests of the West for millennia, but was excluded by human land use for over a century. Fire activity is currently increasing, driven in-part by a combination of increased fuels and increasing aridity. Are the recent “record” levels of area burned large in a historical context? The goal of our research was to reconstruct area burned at the landscape scale using the largest network of tree-ring fire scars for a mountain range in North America: The Jemez Mountains, New Mexico, with > 8,000 fire scars from > 1,300 trees, systematically sampled across > 250,000 ha of montane forest. Reconstructed area burned was compared with modern area burned derived from instrumental fire atlases.
Results/Conclusions
Modern “record” fire years (e.g., 2011 – including the 60,000 ha Las Conchas Fire) were not exceptionally large in terms of area burned in a 350-year context. Multiple historical fire years burned over twice the area of modern record fire years. Even with increasing modern burning, there is still a fire deficit in the Jemez Mountains. Importantly, recent fires have burned with uncharacteristically large patches of high severity fire (> 2,000 ha) that are not present in the historical fire record. These high-severity patches are likely converting centuries-old forests to non-forest. This contrast between area burned and severity emphasizes the need to restore frequent, low- to moderate-severity fire that historically burned with spatial extents unprecedented in the modern record.