Authors: Marin E. Chambers; Paula J. Fornwalt; Mike A. Battaglia; Sparkle L. MaloneWildfires in ponderosa pine - dominated forests of the United States are increasingly burning with a high severity component that is unprecedented in the available historical record. The ability of ponderosa pine and other co-occurring conifers to regenerate in uncharacteristically large and severely burned patches of such fires is unclear, as seeds must disperse from living trees. We measured post-fire regenerating conifers in eleven 10+ year-old fires across Colorado, Wyoming, and South Dakota to characterize regeneration in severely burned patches and how regeneration is governed by site factors. Our preliminary results indicate that conifers have regenerated in severely burned areas at low densities (~125 stems/ha). This contrasts with conifer regeneration in unburned and lightly to moderately burned areas, which was more than four times greater. Furthermore, as distance from living trees increased, conifer regeneration density sharply decreased, suggesting it will likely be compromised in the interiors of large high severity patches; densities averaged ~175 stems/ha 25 m from living trees but <10 stems/ha 250 m from living trees. Conifer regeneration densities were also influenced by coarse wood cover, and presence of regenerating conifers was influenced by aspect, mean annual temperature, and solar radiation.