Spatiotemporal fire dynamics in mixed-conifer and aspen forests in the San Juan Mountains of southwestern Colorado, USA

Mixed-severity fire regimes may be the most extensive yet poorly understood fire regimes of western North America. Understanding their long-term spatiotemporal dynamics is central to debates regarding altered fire regimes and the need for restoration in the context of changing climate and nearly a century of active fire suppression. However, the complexity of fire patterns and forest stand and landscape structures characteristic of mixed-severity regimes poses a substantial challenge to understanding their long-term dynamics. In this study, we develop analysis methods aimed at understanding the fire-driven forest dynamics of mixed-severity systems and apply them in the San Juan Mountains of southwestern Colorado. We sampled fire scars, stand structure, and >4,300 tree ages across two 1,340-ha landscapes (Williams Creek and Squaretop Mountain) that span the environmental gradient of montane mixed-conifer and aspen forests. New approaches were applied to identify pulses of tree recruit...