Taking carbon out of the atmosphere is essential for slowing global warming – and a team of researchers has estimated “huge” potential for carbon capture using a method that’s low-tech, sustainable and relatively simple: burying wood, especially the debris from managed forests.

In the study, published June 25 in Nature Geoscience, researchers found that burying the wood debris from managed forests over the next 76 years could remove between 770 and 937 gigatons of carbon dioxide from the atmosphere (or between 10.1 and 12.3 gigatons of carbon dioxide per year), resulting in a reduction of global temperatures up to 0.42 degrees Celsius (0.76 degrees Fahrenheit).

If the U.S. buried 66% of the wood debris from its managed forests, net zero emissions could be reached by 2050.

“Based on my knowledge, this is the most effective and the least expensive, and possibly the most sustainable way to capture carbon,” said first author Yiqi Luo, the Liberty Hyde Bailey Professor in the School of Integrative Plant Science’s Soil and Crop Sciences Section, in the College of Agriculture and Life Sciences (CALS). “There’s huge potential.”

Managed forests, typically used for logging, produce large amounts of wood debris, which is often burned or left to decompose, emitting carbon dioxide into the atmosphere. Burying the wood debris preserves it in soil and largely prevents carbon dioxide from escaping.

“Soil is a very good natural insulator and can naturally deplete oxygen to prevent wood debris from decomposition and carbon dioxide release,” Luo said. “So, if we bury the wood 2 meters deep, the wood can be preserved there for hundreds, even thousands of years.”

The principle, Luo said, is similar to the idea of planting a tree to capture carbon dioxide, but burying the wood at the end of the tree’s life largely extends that impact and prevents the carbon from reentering the atmosphere.

The authors focused on managed forests, sawmills and discarded furniture as the greatest source of wood debris – with the biggest potential for impact – but the method could apply to urban maintenance, orchards and farms or even college campuses.

“This idea could help Cornell achieve carbon neutrality because Cornell has a huge amount of land,” Luo said.

Burying the wood debris would be relatively inexpensive, especially compared to other methods of carbon capture, and could be done on-site in many contexts, with minimal transportation costs. The researchers estimated that the carbon dioxide emissions of implementation would amount to 2% to 5% of the carbon saved – a relatively low cost.

The practice could also incentivize the removal of debris from forests in areas of high wildfire risk, reducing the amount of fuel for fires while capturing carbon.

“If you can thin the forest enough, the fire will not burn a bigger area,” Luo said. “But currently in the western U.S., the effort is very slow because it’s time-consuming and financially very costly. But if they could sell this wood as a carbon credit, it would provide additional income to manage forest fires.”

Luo, whose previous work pursued basic research about the carbon cycle, was inspired by co-author Ning Zeng, professor at the University of Maryland, who has conducted both theoretical analysis and experiments on the preservation of wood in soil. Luo was also inspired by co-author and Ronald P. Lynch Dean of CALS Benjamin Houlton’s call to faculty to “bend the curve” on global warming.

“I was very stimulated by this idea,” Luo said. “The global temperature is increasing, the carbon concentration is building up, and we thought we could apply a theoretical framework of the carbon cycle science and start to look at application.”

The authors said further large-scale demonstrations are needed to assess the method’s impact on soil health, methane emissions, soil nutrients and biodiversity.

To that end, Luo is collaborating with colleagues at both Cornell AgriTech and on the Ithaca campus to investigate whether orchards in New York state can achieve carbon neutrality by burying wood debris. 

Co-authors of the study from Cornell include Xiangtao Xu, assistant professor (CALS); Ying Sun, associate professor (CALS); Fengqi You, the Roxanne E. and Michael J. Zak Professor in Energy Systems Engineering (Cornell Engineering); Yu Jiang, assistant professor (CALS); Lailiang Cheng, professor (CALS); postdoctoral researchers Ning Wei, Yu Zhou, Feng Tao and Quan Quan; and research associate Lifen Jiang.

The study was supported with funding from the National Science Foundation; the Department of Energy; the U.S. Department of Agriculture; the New York State Department of Environmental Conservation; and the New York State Department of Agriculture and Markets.