How Much Carbon Do California’s Forests Hold?

It’s a tough number to nail down, but a federal program is zeroing in on it

Trees, grasses and freshwater aquatic systems all play a part in the carbon cycle.

The U.S. Geological Survey is developing a series of reports on how much carbon and other greenhouse gases the nation’s ecosystems hold. Trees and plants, soils and rivers, farms and wetlands all sequester carbon to greater or lesser extents. But how much? And how might that number change in the future? That’s the crux of the USGS study, which was initiated by the Energy Independence and Security Act of 2007 [page 223 of the PDF]. (There’s a simultaneous study, also by the USGS, to assess geologic carbon sequestration).

The national assessment will include details on greenhouse gas sequestration nationwide: how much carbon is stored now, how that carbon sink might be altered by different land use scenarios in the future (for example, increased or decreased logging, urbanization, wetland restoration efforts or agriculture), plus impacts from other sources, such as wildfire and climate change.

To tackle this immense project, the agency divided the country into regions. The assessment on the Great Plains came out late last year. Next up is the West, including California, due out this summer.

“The diversity of California is a story in and of itself,” Ben Sleeter, a USGS research geographer who’s working on the assessment told me. The Coast Range, the Klamath Mountains, the Sierra Nevada, the Central Valley and California’s deserts all store different amounts of carbon. There are diverse land management approaches in each area. And future land use options are varied, too. “It’s enormously complex,” he said.

The USGS study won’t gloss over the details. I asked Sleeter if I’d be able to learn the amount of carbon sequestered in the Sierra Nevada, and he said I could get much more specific than that. “If you were curious about an area near (Calaveras) Big Tree State Park, we will be able to summarize the land use changes and carbon sequestration changes for that area.”

To help present the data, the USGS is collaborating with UC Berkeley’s Geospatial Innovation Facility, the group that developed Cal-Adapt, to create a similar tool, which will make the information in the assessment more accessible.


  • Kim Williams

    I’m looking forward to hearing more about this as the study progresses.  Perhaps this will educate politicians & the public about the value of grasslands and agricultural rangelands, not only for carbon sequestration but also as wildlife habitat. Until value is found, big energy will continue to exploit our natural resources for industrial solar energy development instead of pursuing the more efficient distributed energy solutions currently employed by European countries.