Forest

Model projections that show future changes in habitat for many tree species do not account for migration constraints, longevity of current species, or differences among age classes. Because mature trees are expected to remain on the landscape, and recruitment of new species is expected to be limited, major shifts in species composition will not likely be observed by the middle of the century, except along ecoregional boundaries and in areas that undergo major stand-replacing disturbance events.

Climate change impacts are more likely to be observed in seedlings and early growth than in mature trees. Temperature and moisture requirements for seed dormancy and germination are often much more critical than habitat requirements of an adult tree. Predicted changes in temperature, precipitation, growing season onset, and soil moisture may alter the duration or manifestation of germination conditions, and individual species will be uniquely affected.