The forests of the Klamath region of SW Oregon and NW California are some of most diverse and carbon dense conifer forests in the United States. Warmer conditions are expected for this region under climate change, which could result in changing disturbance regimes and recovery rates for these forests leading to insufficient forest regeneration. We simulated forest growth and succession, management, wildfire, and climate change to: 1) assess potential future forest conditions of species composition and aboveground biomass; and 2) to investigate the possibility of a wide-spread shift of mature conifer forest to an alternative stable state of shrubs and chaparral. We hosted two workshops with forest managers in the region, where participants developed six different management scenarios covering a range of forest and fire management activities and intensities to address such changes. These scenarios were modeled under five climate change projections to address the uncertainties of climate change and future policy. We evaluated the relative success of each scenario in terms of the likelihood of forest changes in composition and ecosystem services produced, like carbon storage and biodiversity. We also evaluated impacts of forest management on fire regimes as well.
Initial results indicate that, under climate change, there is a limited potential for vegetation regime shifts as few conifer forests become trapped in a shrub/hardwood state even after multiple fires. This affect was mediated by management activities, like fuels treatments, harvesting, and fire management, altering disturbance patterns. Aboveground biomass continued to increase under all management scenarios as forests continue to recover from past disturbances. However, there were a range of responses of aboveground biomass to climate change scenarios. Fire regimes changed significantly under both different management and climate scenarios. This research will assist forest managers and stakeholders in the region to develop comprehensive climate resilient management plans.