Lungs of the Earth: The Top 10 carbon storing national forests in America

One of America's Top 10 National Forest, the Siskiyou National Forest in Oregon. Courtesy KSWild.

Ever hear the old adage that trees are the “lungs of the earth?” It creates an awesome visual and brings a human element to the towering giants that fill our forests. But did you know that forests in the Pacific Northwest and Southeast Alaska are among the Earth’s strongest “lungs?”

Just how strong are they? The Wilderness Society recently analyzed United States Forest Service data and found that the top ten national forests in the United States that store the most carbon per forested acre are all located in Washington, Oregon and Southeast Alaska.

That means many of the beautiful old growth forests that Americans love to marvel at are also among the Earth’s greatest carbon-storing ecosystems — and our best tools for combating climate change.

In fact, per acre these densely packed Pacific forests hold as much or more carbon than the average tropical rainforest that deforestation debates usually center on, yet many of them continue to go unprotected from logging and development.

Perhaps you’ve visited one or more of them. They are:

Why These Forests Matter

Our forests have long been recognized as providing great outdoor recreation opportunities as well as important habitat to a number of species, including the imperiled spotted owl and marbled murrelet. But forests also do something that we can’t see with our own eyes: they breathe in air filled with carbon, such as carbon dioxide, a greenhouse gas that contributes to global warming, and store it within the trees cells, roots and even soil. I like to think of these forests as gigantic piggy banks, storing up the carbon to help us combat the threat of climate change.

Graphic<br />
representing Carbon in Ten Most Carbon-Dense National Forests, Compared<br />
to  Annual U.S. GHG EmissionsThe ten national forests in the U.S. with the highest carbon density hold an average of approximately 500 metric tons of carbon-dioxide-equivalent (CO2e) on each forested acre.

Altogether, these forests store approximately 9.8 billion metric tons CO2e on about 19 million acres, which is equivalent to all the fossil fuels that are burned in the U.S. over a year — about 5.8 billion metric tons.

Some of this carbon is stored in living trees and other vegetation, both above and below ground, some in standing or down dead wood, and some in soil.

The United States’ top ten national forests are among the great carbon-storing forests in the world. For international comparisons, the average global tropical forest stores about 360 to 460 metric tons of CO2e per acre, boreal forests 430 to 600 metric tons (mostly in the soil) and temperate forests 220 to 420 metric tons.

Clearcut in Tongass National Forest. Photo by Karen Hardigg.And yet more than a million acres of these top ten national forests — one of the greatest carbon banks on Earth — are not formally protected and are vulnerable to destructive logging.

The federal forests in the Pacific Northwest and Southeast Alaska — especially the old growth and mature forests — store tremendous amounts of carbon that are vitally important to America’s ability to combat climate change.

The Wilderness Society strongly encourages the Obama administration to take action to protect the 1.5 million acres of valuable mature and old growth forests for their ability to store carbon, along with the many other important services that healthy forests provide — from clean water to wildlife habitat and recreation opportunities.

One of America's Top 10 National Forest, the Siskiyou National Forest in Oregon. Courtesy
Clearcut in Tongass National Forest. Photo by Karen Hardigg.