Manage Forests for Climate Change
Approximately one-third of the United States is forested, which amounts to about 745 million acres of forest. Forested ecosystems vary dramatically, based upon their geologic and climatic conditions, and are expected to change significantly in response to climate change. Much of New England is currently dominated by maples, beeches and birches, for example. But, by the end of this century, those forests are expected to have shifted toward an oak-hickory defined ecosystem.
Climate Change Impacts: Current and Predicted
Forests occur in every region of the United States, and the response of a specific forested ecosystem will depend on a variety of factors, including changes in temperature, precipitation and species composition.
Observed and predicted climate change impacts to forests may include:
- Stronger and more frequent forest fires, due to generally warmer temperatures and drier conditions.
- Species — both plants and wildlife — shifting their ranges to the north, or to higher elevations. For example, the tree-line is already encroaching on tundra in Alaska.
- The expansion or contraction of classic forest types — e.g. oak-hickory or maple-beech-birch — due to rising temperatures and changing species composition. Some forest types, such as spruce-fir, may disappear entirely from the United States.
- Greater risk of disease and insect pests, including the potential for these stressors to shift their ranges further north, or to higher elevations.
- Shifting seasons, which may push plants and pollinators out of synch with one another.
- Some tree species may respond to higher levels of carbon dioxide by growing faster. However, this is expected to be a relatively short-term scenario.
Additional information about predicted climate change impacts to forested habitats, ecosystems and wildlife can be found in the following places:
- Global Climate Change Impacts in the United States,
- Forests Impacts & Adaptation, EPA,
- U.S. National Assessment of the Potential Consequences of Climate Variability and Change,Sector: Forests.
Recommendations for Adaptation
Climate change is already altering the species composition of forests across the United States, allowing some trees to extend their ranges further north or to higher elevations, for example. These changes — and others — will continue throughout the coming century.
Land trusts that manage forested habitats may wish to:
- Assess the vulnerability of the property;
- Consider scenario planning;
- Adopt an adaptive management policy.
Specific recommendations for the adaptation of forested habitats to climate change include:
- Assess vulnerability of habitat(s) to climate change impacts, such as shorter winters, earlier springs or dryer summers. Note: these impacts will vary by region and forest type.
- Determine whether currently protected habitats are likely to shift their range northward, or to higher elevations. If so, consider the feasibility and value of extending the protected area’s boundaries to include this new territory.
- Increase the overall health and resilience of existing habitats by removing invasive plants, restoring native species, and protecting habitats from development and other stressors.
- Wherever possible, protect the health of established ecosystem services, such as stream buffers, which may help support the health of the whole forest.