Projections of future fire risks point to increased fire frequency and increased numbers of large fires in the Sierra Nevada region. As warmer temperatures reduce snow-covered area, induce early snowmelt, and decrease soil moisture, they contribute to longer and warmer fire seasons. The management and uses of forest ecosystems and resources will be impacted as forests change along with changing climate and fire regimes. In some areas, forests may be replaced with shrublands, grasslands, or deserts. Climate change effects on forests will be driven by the rate and magnitude of climate change, site-specific conditions, the ability of species to shift distributions through dispersal and recruitment, and the influence of other ecological stressors. While climate-change impacts on structure, composition, and ecosystem function play out over longer time periods, fire can hasten these changes by triggering changes in vegetation type.

Successful adaptation for these important forests will require a mix of large- and small-scale approaches to challenges. There are key management issues and adaptation options at various levels: the southwest region overall, the Sierra Nevada, forests, and all the way down to trees.