Forests in the eastern United States are changing in response to ecological succession, tree harvest, and other disturbances and climate change has the potential to further change these forests. We predicted the distribution and abundance of common tree species across portions of the eastern U.S. under alternative climate scenarios that varied in the amount of warming by the end of the century from 1.1 to 4.2 degrees celsius. We used a forest landscape change model to forecast changes in tree abundances and distribution in the North Atlantic region of the U.S. while accounting for climate change, succession, and harvest. We then considered a broader region of the U.S. and combined our results with results from previous studies to compare forecasts from three different modeling approaches for the Central Hardwood, Central Appalachian, Mid-Atlantic, and New England regions to determine the level of agreement among models.
Our forecasts for the North Atlantic region indicated tree abundances were affected first by succession and harvest but second by climate. We predicted an increase in Southern and Central Hardwood species and a decrease in Northern Hardwood and spruce-fir forest species under warming climates over the next 300 years. Our comparison of the three modeling approaches across the eastern U.S. indicated high agreement for many species, especially northern species modeled to lose habitat in coming decades. There was agreement among models for decreases in black spruce, balsam fir, northern white cedar, and red spruce, and increases in loblolly pine and some oaks and hickories. Agreement across different modeling approaches and different climate scenarios provides strong evidence of potentially important changes to forests in response to climate change. These results can be used to guide decisions about how to manage forests under climate change to continue to provide the benefits we derive from them.
