Forest resilience, climate change, and opportunities for adaptation: A specific case of a general problem

Ecosystems and ecosystem services are subjected to both typical disturbances (e.g., fire) and shifting climatic baselines resulting from anthropogenic drivers. Recovery from these perturbations is of prime interest to researchers and land managers. We explore how differing regeneration of the coniferous forest to specific disturbances and a shifting climate are mediated through managerial responses, in terms of both species composition and an important ecosystem service, carbon sequestration in the southern Rocky Mountains, Colorado, USA. 112 sites across a variety of disturbance histories were surveyed for post-fire regeneration; carbon stock growth was then simulated in the US Forest Service Forest Vegetation Simulator under a variety of climate change scenarios for 100 years. Simultaneously, we simulated three managerial responses to the disturbance: no action, planting of local species (resilience-oriented management), and planting of the most climatically suitable species (adaptation-oriented management). These managerial responses simulate varying levels of intervention which attempt to maintain forest properties and associated carbon stocks. Carbon stocks, initially, were more resilient than the coniferous forest system; areas with little coniferous regeneration recovered carbon at a similar pace due to an influx of deciduous seedlings. However, future climate exerts a strong influence on carbon stocks. Both the no-action scenario and the resilience-oriented management scenario transitioned to non-forest by the end of the simulation period, due to climatic changes. Active, adaptation-oriented management, which included establishment of non-local species, maintained forest structure and carbon stocks under most future climate projections, albeit at lower densities. So while this preserves the presence of a forest, it does not preserve the presence of a specific forest. However, for ecosystem services associated with the mere existence of forest cover (e.g., carbon stocks and general forest habitat), this may be sufficient. In a sense, disturbances are opportunities for more climatically-adapted species/communities to establish, although the complexities of assisted migration and novel ecosystems remain.