Burying wood debris can remove large amounts of carbon dioxide from the air

Over the next 76 years, a simple low-tech capture method can remove nearly 1,000 kupats of carbon dioxide from the atmosphere to reduce global temperatures up to 0.42°C.

Cornell researchers have burying wood debris is the most cost-effective way to remove carbon on a large scale, using waste that has been mass-produced by forests and sawmills.

The study published in Natural Earth Sciences shows that woody debris buried from deep soil preserves carbon for hundreds or thousands of years, rather than letting it break down and release carbon dioxide back into the atmosphere. If the United States buried only 66% of its forest wood waste, the country could reach zero emissions by 2050.

The carbon dome of nature

This method utilizes the natural properties of the soil as an insulator and an oxygen-depleting environment. Although the surface wood decomposes rapidly, releasing stored carbon as carbon dioxide, under low oxygen conditions, the buried wood is still stored only 2 meters underground.

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

The oxygen concentration drops sharply with soil depth – from 21% on the surface to 1% deep, at two meters, less than 0.1%. This creates an environment where the decomposition speed slows down orders of magnitude compared to surface conditions.

Large-scale, minimal infrastructure

Researchers calculate that globally managed forests produce about 14.1 gitton of wood debris each year through logging operations, sawmill waste and discarded furniture. Currently, most of these materials are burned or left to break down, bringing their carbon back to the atmosphere quickly.

The burial process requires surprisingly modest infrastructure:

• Land efficiency: Soil storage 100×100×10 meters can store 0.1 megatons of carbon dioxide from debris collected from 2500 square kilometers.
• Discovery scale: Storage of 1 gigabit of carbon dioxide will require soil excavation comparable to the burj khalifa in Dubai
• Energy Cost: Machine operations for collection, burial and soil cap account for only 2-5% of stored carbon
• Land Reuse: Buried vaults can be capped and used to grow crops, trees or grasslands

Verified Carbon Accounting

Unlike many carbon capture methods that rely on complex modeling, wood burial provides direct measurement and verification. The carbon content of wood debris can be reliably quantified by weighing and measuring carbon concentration. A gas analyzer can be used to monitor preservation effects to detect the release of carbon dioxide and methane from the burial site.

“Based on my knowledge, this is the most efficient, least expensive, and perhaps the most sustainable way to capture carbon,” Luo stressed. “There is great potential.”

This measurement accuracy enables reliable carbon credit trade, and some wood burial projects have begun to operate in the voluntary carbon market.

Multiple environmental benefits

In addition to removing carbon, wood debris burial can provide important common benefits, especially in areas where it is prone to occur. Removing wood debris reduces surface fuel availability, potentially reduces wildfire intensity, and releases 7.7 gig times of carbon dioxide from global fires each year.

This approach can also help manage urban wood waste in tree pruning and maintenance, resulting in carbon-negative waste disposal when solving common municipal challenges.

Using three Earth system models to analyze different situations, the researchers found that between 2025 and 2100, the annual wood fragment production was extended by 100 to 2,000 years, allowing 769-937 gigabits of carbon dioxide to be removed. This represents the average annual deletion of gigatons between 10.1 and 12.4 gigatons.

Research Focus

While promising, the method requires extensive field testing before large-scale implementation. Key research priorities include monitoring methane production under anaerobic burial conditions, assessing the impact on soil health and biodiversity, and optimizing techniques to further extend wood storage time.

The group noted in particular that the approach should focus on real waste (debris, sawmill waste and urban tree maintenance) rather than harvesting timber specifically for burial, which could undermine forest conservation efforts.

Luo and colleagues are already investigating whether orchards in New York State can achieve carbon neutrality by burying pruned wood debris, suggesting that the approach’s potential goes beyond agricultural applications beyond forestry.

As climate goals become increasingly urgent, the study shows that using the scientific principles of carbon cycle to turn rich waste streams into powerful climate tools, some of the most effective carbon removal solutions may be low-tech.

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