Burying Wood Debris Could Remove Massive CO2 from Air

A simple, low-tech approach to carbon capture could remove nearly 1,000 gigatons of carbon dioxide from the atmosphere over the next 76 years—enough to cool global temperatures by up to 0.42°C.

Cornell University researchers have identified wood debris burial as potentially the most cost-effective method for large-scale carbon removal, using waste materials that forests and sawmills already produce abundantly.

The study, published in Nature Geoscience, shows that burying wood debris from managed forests in deep soil preserves the carbon for hundreds or thousands of years instead of letting it decompose and release CO2 back into the atmosphere. If the United States buried just 66% of its forest wood waste, the country could reach net-zero emissions by 2050.

Nature’s Carbon Vault

The method takes advantage of soil’s natural properties as an insulator and oxygen-depleting environment. While surface wood decomposes rapidly, releasing stored carbon as CO2, buried wood remains preserved in the low-oxygen conditions found just two meters underground.

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

Oxygen concentrations drop dramatically with soil depth—from 21% at the surface to about 1% at one meter deep and less than 0.1% at two meters. This creates an environment where decomposition slows by orders of magnitude compared to surface conditions.

Massive Scale, Minimal Infrastructure

The researchers calculated that managed forests worldwide produce approximately 14.1 gigatons of wood debris annually from logging operations, sawmill waste, and discarded furniture. Currently, most of this material is burned or left to decompose, rapidly returning its carbon to the atmosphere.

The burial process requires surprisingly modest infrastructure:

• Land efficiency: A soil vault 100×100×10 meters could store 0.1 megatons of CO2 from debris collected across 2,500 square kilometers
• Excavation scale: Storing 1 gigaton of CO2 would require soil excavation comparable to building Dubai’s Burj Khalifa
• Energy costs: Machine operations for collection, burial, and soil capping account for just 2-5% of the carbon stored
• Land reuse: Buried vaults can be capped and used for growing crops, trees, or grassland

Proven Carbon Accounting

Unlike many carbon capture approaches that rely on complex modeling, wood burial offers straightforward measurement and verification. The carbon content of wood debris can be reliably quantified by weighing and measuring carbon concentration. Preservation effectiveness can be monitored using gas analyzers to detect CO2 and methane release from burial sites.

“Based on my knowledge, this is the most effective and the least expensive, and possibly the most sustainable way to capture carbon,” Luo emphasized. “There’s huge potential.”

This measurement precision enables reliable carbon credit trading, and some wood burial projects have already begun operating in voluntary carbon markets.

Multiple Environmental Benefits

Beyond carbon removal, wood debris burial could provide significant co-benefits, particularly in fire-prone regions. Removing woody debris reduces surface fuel availability, potentially decreasing wildfire intensity and the associated release of 7.7 gigatons of CO2 annually from global fires.

The approach could also help manage urban wood waste from tree pruning and maintenance, creating carbon-negative waste disposal while addressing a common municipal challenge.

The researchers used three Earth system models to analyze different scenarios, finding that preserving annual wood debris production with residence times lengthened by 100 to 2,000 years could remove 769-937 gigatons of CO2 between 2025 and 2100. This represents 10.1-12.4 gigatons removed annually on average.

Research Priorities Ahead

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

The team specifically noted that the method should focus on genuine waste materials—logging debris, sawmill waste, and urban tree maintenance—rather than harvesting wood specifically for burial, which could undermine forest conservation efforts.

Luo and colleagues are already investigating whether New York state orchards could achieve carbon neutrality by burying pruned wood debris, demonstrating the method’s potential for agricultural applications beyond forestry.

As climate targets become increasingly urgent, this research suggests that some of the most effective carbon removal solutions might be surprisingly low-tech, using principles of carbon cycle science to turn abundant waste streams into powerful climate tools.corn