Are historical fire regimes compatible with future climate? Implications for forest restoration

The restoration of historical fire regimes is often a primary objective in the conservation o fire-Adapte forests. However, individual species'[ responses to future climate change may uncouple historica vegetation-disturbance relationships, producing potentially negative ecological consequences t fire restoration. We used a landscape simulation model to assess how forest pattern will respond to futur climate regimes and whether the restoration of historical fire regimes will benefit forest conservatio unde future climate regimes. Our study landscape was the 335,000-h Kaibab Plateau at the North Ri of the Grand Canyon spanning a broad elevation-vegetatio gradient of pinyon-juniper ponderosa pine mixed conifer, and spruce-fi forests along with a range of associated fire regimes. We employed a nove multimodel landscape simulation approach using the Climate-Fores Vegetation Simulator to estimat individual tree species climate responses and LANDIS-I to simulate spatial patterns of fire disturbance forest growth, regeneration, succession, and dispersal. Model simulations included three climate scenario (no change, moderate change, and high change) and two fire scenarios (fire exclusion and fire restoration) The climate change scenarios produced declines in mean forest aboveground biomass (AGB) and a compositiona turnover equal to one or two vegetation zones, approximating the vegetation displacement tha occurred in this location during the Holocene. Fire restoration resulted in earlier, but roughly equivalent AGB declines and compositional change. Uphill species migration in some elevation zones produced tre species fire regime mismatches that promoted state changes and increased nonforest area. Regardless o fire management approach, our simulations project that the Kaibab Plateau will eventually be dominate by pinyonh-juniper oak, and ponderosa pine forest types, with a complete loss of mesic conifer species Our results indicate that fire managers will have to be flexible with the application of historical fire regime to avoid regeneration failures and abrupt declines in biomass.