Pacific Northwest forests could store more carbon, help address greenhouse issues

Many economic, ecological and land management issues come into play, the researchers said, and the recent study does not consider what effect increases in temperature or changes in precipitation might have on these lands, or the implications that might have for catastrophic forest fire. But looked at from nothing more than a carbon offset perspective, the optimal approach would be to leave the forests alone, the scientists said.

"Increasing carbon storage in this region might be one contribution to what clearly is a much larger global issue, something that policy makers could consider," Law said. "A lot of land management approaches are now being seen as a short-term bridge to a period where we will be using fewer fossil fuels and addressing carbon issues in other ways."

Largely because of its many forests, researchers say the various "carbon sinks" in Oregon already sequester from 30-50 percent of the emissions caused by use of fossil fuels in the state. That's much better than many other states or the national totals, Law said.

Among the findings of the report:

• About 65 percent of the live and dead biomass in this region is on public lands, while private lands often have younger age classes of vegetation and less total biomass;
• Contrary to accepted views on biomass stabilization and decline, biomass is still increasing in stands more than 300 years old in the Coast Range, Sierra Nevada and the West Cascade Range, and in stands more than 600 years old in the Klamath Mountains;
• The entire study region of Oregon and Northern California, as far south as San Francisco, holds a total live biomass of about two billion tons of carbon – about 14 percent of the biomass in the whole nation;
• If forests in this region were managed over hundreds of years to maximize carbon sequestration, the carbon in live and dead biomass could theoretically double in the Coast Range, west and east Cascade Range and Sierra Nevada; and triple in the Klamath Mountains.

This research was supported by the Biological and Environmental Research Terrestrial Carbon Program of the U.S. Department of Energy. It was published in Ecological Applications, a professional journal.