The Future of Forests under a Changing Climate: Opportunities and Challenges
Introduction
Forests are critical ecosystems that provide clean air, water, habitats for wildlife, timber, and spaces for recreation. However, climate change is expected to significantly impact forest health and the provision of these important services. This article introduces the different ways that climate change is expected to influence the future of forests and highlights the resources made available by the USDA Climate Hubs to forest owners and managers.
Collaborative Efforts to Support Forest Resilience
The USDA Climate Hubs are collaborative networks that bring together various USDA agencies to provide science-based tools and information on climate change. These networks are tailored to address the specific needs of different regions across the US. They work with farmers, ranchers, forest landowners, and natural resource managers to help them understand climate risks and the potential impacts on their lands. By offering education, resources, and practical solutions, the USDA Climate Hubs aim to improve forest resilience and boost rural productivity. The sections below offer a brief overview of what to consider while managing forests under climate change and highlight some of the resources provided by the USDA Climate Hubs to address these challenges.
Extended Growing Seasons
As global temperatures rise, the growing season, spring and summer, is expected to lengthen. This change may have both positive and negative outcomes for forests.
On the positive side, extended growing periods could increase carbon sequestration, or the amount of carbon stored in trees. As trees photosynthesize for a longer period, they absorb more carbon dioxide (CO2) from the atmosphere. This increased carbon uptake helps mitigate climate change by reducing the concentration of greenhouse gases in the atmosphere. Additionally, farmers may benefit from longer growing periods, experiencing higher crop yields due to multiple crop cycles, which could improve food security. A longer growing season is also expected to support wildlife populations, providing them with more food and better habitats.
However, a longer growing season may also present challenges. For example, a "false spring" may occur when warmer weather arrives too early in late winter, causing plants to grow before they are ready. If a subsequent cold spell occurs, it could damage plants, affecting their survival, productivity, and ability to reproduce. For more details on what to expect under changing growing seasons, check out these articles: Climate Warming Brings Earlier Spring and Shifts in Growing Degree Days Plant Hardiness Zones and Heat Zones.
Forest Transition
Forest Succession
Many forests—particularly natural and rural ones—undergo a process called succession, where different species of plants and trees gradually replace each other over time. This often happens after disturbances such as wildfires, pest outbreaks, storms, or droughts. Read more about different types of disturbances. While disturbances are a natural part of forest dynamics, climate change is expected to alter both their frequency and intensity. To learn about the various challenges forests face, keep reading below and visit the Emerging Forest Threats- State Fact Sheets.
Altered Disturbance Patterns
Disturbances present both opportunities and challenges for forests. On the opportunity side, increased disturbances could accelerate tree mortality, allowing new forest types to emerge. For example, northern hardwood species (e.g., sugar maple, American beech) are predicted to shift northward under a warming climate, while mixed deciduous-coniferous forests may decline in favor of temperate hardwood forests.
On the challenges side, frequent disturbances make it harder for forests to recover. Hotter and drier conditions often lead to more wildfires and drought, which can weaken trees, young and old, making them more susceptible to pest outbreaks, disease, and death. Learn more about pest outbreaks in these articles: Insects Change the Story, The USDA Southeast Climate Hub 2021 Southern Pine Beetle Outbreak Risk Forecast, and Forecasting Short- and Long-Term Southern Pine Beetle Risk in the Southeastern US.
When trees die or are weakened by disturbances, invasive plant species (e.g., multiflora rose, Japanese stilt grass, and kudzu) may take over the landscape, further stifling forest regeneration (Knapp et al., 2023). In the mid-Atlantic region, deer browsing pressure, combined with invasive species, adds to the ongoing failure of oak tree regeneration. Learn more about different types of forest vulnerabilities in these articles: Northern Forests Vulnerability, Mid-Atlantic Forest Ecosystem Vulnerability Assessment, and New England and Northern New York Forest Ecosystem Vulnerability Assessment.
Extreme Weather Events
Weather-related extreme events such as heatwaves, heavy rain, tornados, and floods can also significantly impact ecosystems. Extreme events are usually short-lived, but under climate change, they are predicted to be more frequent and last longer. These events can be damaging to forest health and forest recovery over time. A recent example is the 2024 catastrophic flooding and landslides in western North Carolina brought on by Hurricane Helene. The storm caused unprecedented damage, with over 1,900 landslides reported in the area. For more information on extreme events, visit the Extreme Weather page. Prolonged droughts are another extreme event that can reduce the nutrients available to plants. Following droughts, heavy rainfall can wash away vital nutrients from the soil. To learn more about this, read Drought in Northern Forests.
Global changes in climate have already contributed to rising sea levels. This, along with extreme weather events in coastal areas, helps expand saltwater intrusion into freshwater areas, leading to widespread tree mortality. Minimizing these impacts in flood-prone areas often requires the restoration of wetlands and coastal buffers to absorb excess water and protect habitats along rivers. Read more about coastal forests under climate change, including Climate Change Impacts to Coastal Forests, and Saltwater Intrusion and Salinization on Coastal Forests and Farms.
Strategies for Managing Disturbances and Adapting to Climate Change
To help forests withstand the challenges of climate change, forest managers can adopt strategies that build resilience within the ecosystem. For example, planting native species that are well-suited to local or expected future conditions can reduce the risk of frost damage and stress caused by temperature fluctuations (EIP- AGRI, 2019). Maintaining diverse forests with varying tree species, ages, and sizes can help create microclimates that protect against extreme weather events (Kearney et al., 2009; Kasper et al., 2012). Diverse forests make better use of water and sunlight and improve soil health (Reubens et al., 2007; Ammer, 2019), and are often less impacted during times of disease or pest outbreaks because most pests target only a few select tree species (e.g., emerald ash borer) and leave other tree species alone (Bauhus et al. 2017).
Other strategies that protect forest health include avoiding thinning late in the season, which can delay the hardening process of trees, making them more vulnerable to early frosts (Charrier et al., 2021). Prescribed burns, small, controlled fires, can reduce the risk of large wildfires and promote fire-resistant plant growth (Sample et al., 2022). Forest managers can also control pests by preventing their spread, treating affected trees, and removing infected trees when necessary (Klapwik et al., 2016; Secretariat et al., 2021). Regular monitoring of tree health and weather patterns is also useful for adapting your management practices as conditions change (Keenan, 2015).
Traditionally, forest management has been reactive, addressing damage only after it occurs. However, with climate change intensifying these challenges, forest managers may need to adopt a more proactive approach. By anticipating risks and taking preventive measures, managers can better protect forests and ensure their resilience in the long term. Learn more about proactive forest management strategies in these resources: Forest Adaptation Menu, Mitigation Opportunities, and Planting Trees for a Changing Climate.
This article was produced by the Forest Owner Carbon and Climate Education (FOCCE) program.
If you have any questions or are interested in collaborating with FOCCE, please reach out to Melissa Kreye at mxk1244@psu.edu.
References
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Bauhus, J., Forrester, D. I., Gardiner, B., Jactel, H., Vallejo, R., & Pretzsch, H. (2017). Ecological stability of mixed-species forests. Mixed-species forests: Ecology and Management, 337-382.
Charrier, G., Martin-StPaul, N., Damesin, C., Delpierre, N., Hänninen, H., Torres-Ruiz, J. M., & Davi, H. (2021). Interaction of drought and frost in tree ecophysiology: rethinking the timing of risks. Annals of Forest Science, 78, 1-15.
EIP-AGRI Focus Group on Protecting Fruit Production from Frost Damage. (2019). Final Report. (accessed on 6 March 2024).
Kearney, M., Shine, R., & Porter, W. P. (2009). The potential for behavioral thermoregulation to buffer “cold-blooded” animals against climate warming. Proceedings of the National Academy of Sciences, 106(10), 3835-3840.
Keenan, R. J. (2015). Climate change impacts and adaptation in forest management: a review. Annals of forest science, 72, 145-167.
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Knapp, L. S. P., Coyle, D. R., Dey, D. C., Fraser, J. S., Hutchinson, T., Jenkins, M. A., ... & Wang, G. G. (2023). Invasive plant management in eastern North American Forests: A systematic review. Forest Ecology and Management, 550, 121517.
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