OOS 67-1 - Widespread exposure to fire-regime change will transform conifer forests but ecosystem feedbacks may support persistence

Fire-catalyzed transformations pose challenges for managing forest ecosystems under climate change. Whether and where feedbacks that alter fire activity and reduce vulnerability to transformation will emerge is unknown. We 1) quantified exposure of conifer forests to fire-regime change using climate analogs; 2) explored the direction and spatial distribution of feedbacks reflected by changes in burn severity; and 3) contextualized exposure with spatial information about fire-resistance traits. We measured exposure by comparing contemporary distributions of vegetation productivity, burn severity, and fire frequency to those supported under 2 °C warming. Some 96% of conifer forests will be exposed to fire-regime change, with burn severity projected to decline across 63%. Pinyon-juniper and spruce-fir forests are vulnerable to transformation, despite representing disparate portions of climate space. Forests’ adaptive capacity could support resilience to future disturbance regimes, but pathways remain uncertain. The potential changes we document motivate planned adaptation to protect valued characteristics of conifer forests.