SRS Contributes to Fourth National Climate Assessment

Forests cover 896 million acres of the U.S. and provide clean drinking water, timber and non-timber forest products, wildlife habitat, carbon storage, and many other services. Photo by Valerius Tygart, CC 2.0.

Long hours, lots of reading, and collaborating with fellow scientists around the world is some of what goes into overseeing a chapter for the Fourth National Climate Assessment (NCA4). SRS senior research ecologist James Vose was a federal coordinating lead author and chapter lead for Chapter 6 – Forests of the NCA4. SRS senior economist Jeffrey Prestemon served as a chapter author.

“Our expert team of authors and technical contributors were critical to the success of the chapter,” says Vose. “We focused on the best available science, and it is our hope that the report provides the scientific foundation to inform decisions about climate change adaptation practices on public and private forest lands. The work that goes into the Chapter is a scientifically rigorous process that included peer review from the National Academies of Science.”

NCA4 is a 1,500 page congressionally mandated report by the U.S. Global Change Research Program. The primary objective of NCA4 is to help stakeholders better identify, avoid, or reduce climate-related risks. NCA4 does not evaluate policy or make policy recommendations.

For the chapter on U.S. forests, nearly 200 publications along with publicly available data were used. SRS scientists contributed about one quarter of the peer-reviewed publications referenced in Chapter 6.

There are three key takeaways from the Forests chapter:

  • It is very likely that more frequent extreme weather events will increase the frequency and magnitude of severe ecological disturbances, driving rapid (months to years) and often persistent changes in forest structure and function across large landscapes. It is also likely that other changes, resulting from gradual climate change and less severe disturbances, will alter forest growth and health, as well as the distribution and abundance of species at longer timescales (decades to centuries).
  • It is very likely that climate change will decrease the ability of many forest ecosystems to provide important ecosystem services to society. Tree growth and carbon storage are expected to decrease in most locations as a result of higher temperatures, more frequent drought, and increased disturbances. The onset and magnitude of impacts on water resources in forest ecosystems will vary but are already occurring in some regions.
  • Forest management activities that increase the resilience of U.S. forests to climate change are being implemented, with a broad range of adaptation options for different resources, including applications in planning. The future pace of adaptation will depend on how effectively social, organizational, and economic conditions support implementation.

This is not the first time that Vose has served as an NCA report author. For NCA3, he was the co-lead author along with emeritus scientist David L. Peterson of the Pacific Northwest Research Station and Toral Patel-Weynand, director of Sustainable Forest Management Research.

In autumn 2016, a prolonged dry period and arson led to 50 major wildfires in the southern Appalachians. In Gatlinburg, TN, wildfire caused 15 deaths and destroyed 2,500 structures. If drought or prolonged dry periods increase in this region as expected, fire risk will increase in both forests and local communities. Photo by Michael Tapp.

“We provided the technical input document that served as the science foundation for the forest chapter in NCA3,” adds Vose. Peterson again joins Vose on the NCA4 report, as a federal coordinating lead author and chapter lead for Chapter 6.

“My contribution was based on my research in wildfire projection modeling for the southern U.S. and in regional, national, and international forest product sector modeling, including the Resources Planning Act Assessment,” says Prestemon. “Having the opportunity to contribute to this nationally and globally important research-based assessment, providing potentially useful information for landowners, land managers, and other decision makers has boosted the relevance of my work.”

“I also see how it has added great weight to the research of other scientists in the federal government. I was able to observe how difficult and complex such an assessment process is, making me grateful for the leadership shown by Vose and other lead authors of NCA4 chapters,” says Prestemon.

Read Chapter 6 of the NCA4 on Forests.

For more information, email James Vose at or Jeffrey Prestemon at

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