carbon

Experiments in California ecosystems demonstrate the swiftness and strength of forest fires.

Researchers at Northern Arizona University are discovering that some current forest carbon accounting strategies might be doing more environmental harm than good.

“Fire suppression policy and climate change are causing larger, more severe fires in many forests in the western United States, which release carbon to the atmosphere,” said Matthew Hurteau, a research associate in NAU’s Merriam Powell Center for Environmental Research.

Hurteau explained that since trees reduce climate change effects by storing carbon and not letting it loose into the air, emerging carbon accounting policies provide funding incentives for managing forests packed with trees. However, Hurteau supports thinning forests to protect them from fires that cause even greater amounts of carbon to be released into the air.

Research also suggests that forest fires release about 5 percent of total annual U.S. greenhouse gas emissions, a contribution equal to about one-third of the transportation sector.

“Current carbon accounting in California penalizes forest managers for thinning the forest because it reduces the amount of stored carbon in trees, but this same accounting does not penalize carbon emissions from wildfires,” Hurteau said. “By thinning and consolidating carbon in fewer trees, the forests are more resistant to fire spreading and becoming catastrophic.”

NAU’s research is revealing that thinning forests not only reduces the risks for catastrophic fires and the huge quantities of carbon dioxide that they release into the air, but that the thinned wood is possible fuel for electricity generation.

Hurteau used a computer model to study the century-long, tree-based carbon storage effects from eight forest treatments, with and without forest fires. The research revealed that unthinned forests did store the most carbon, but when wildfire was included, it not only reduced the number of trees available to store carbon, the fire caused a huge emission of carbon back into the air.

The research also examined four of the largest wildfires in the United States in 2002 and discovered that prior thinning could have reduced the amount of carbon released into the air by 98 percent.

“We need to update carbon sequestration policies, which now fund forests based on how much carbon they are capturing and storing,” he said. “Managing our forests based on scientific understanding of the processes that promote a fully functioning system should be the focus of our actions. Carbon storage should be viewed as just one of the many services that forests provide.”

Hurteau’s research was recently published in the journal Frontiers in Ecology and the Environment and appeared at www.earthwire.org.