There’s carbon in them thar hills: But how much? Could Pacific Northwest forests store more?

Abstract

As a signatory to the United Nations Framework Convention on Climate Change, the United States annually compiles a report on the nation’s carbon flux—the amount of carbon emitted into the atmosphere compared to the amount stored by terrestrial landscapes. Forests store vast amounts of carbon, but it’s not fully understood how a forest’s storage capacity fluctuates as stands age or respond to disturbance. To calculate the carbon flux in the forests of Oregon and Washington, scientists with the U.S. Forest Service Pacific Northwest Research Station compiled field measurements and quantified the amount of carbon accumulated or released in relation to a forest’s age, disturbance history, and species of trees. The scientists found that forested lands store carbon at a rate of 7 million metric tons per year. Although older forest stands and individual large trees store more carbon than younger trees, younger forests and small trees accumulate carbon at a faster rate per acre. Wildfires had a minor impact on regional carbon storage, while changes in management practices on federal lands since the 1990s are primarily responsible for the increase in carbon storage in Oregon and Washington forests.

Citation

Watts, Andrea; Gray, Andrew; Whittier, Thomas. 2017. There’s carbon in them thar hills: But how much? Could Pacific Northwest forests store more? Science Findings 195. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.