Montérégie | A 3775-year-old strain discovered in Saint-Pie

Roger Beaudry found a completely preserved stump, 3775 years old, on his land in Saint-Pie, in Montérégie. Its discovery could help reduce greenhouse gases, according to a scientific study published last Thursday.

It all started with a project to revitalize a watercourse on Mr. Beaudry’s land, in Montérégie, in 2013. “There was work to remove tree jams on the watercourse” , explains Ghislain Poisson, agronomist at the Quebec Ministry of Agriculture, Fisheries and Food (MAPAQ).

“Mr. Beaudry planned to get rid of the wood by burning it. We offered him the opportunity to participate in a pilot project for burial in clay, to prevent it from rotting,” says Mr. Poisson, who is among the authors of the study published in the journal Science last Thursday.

This approach, called “wood vault” (wood vaulting), was proposed by the team of Ning Zeng, a climatologist from the University of Maryland whose work Mr. Poisson had seen.

Mr. Beaudry’s trees were therefore buried at different depths 11 years ago. That’s when the mysterious strain was discovered.

“It looked very old,” said the farmer, on the sidelines of a long day spent in his soy fields.

Mr. Poisson kept the piece of wood in his office for several years. Then, in 2019, trees buried on his land were dug up and sent to Maryland for analysis. The mysterious strain was also sent to the laboratory.

The results stunned the researchers: despite its venerable age, the stump had not rotted. It had lost less than 5% of its initial carbon. And therefore, it had not emitted the greenhouse gases (GHG) associated with rotting. Nor, obviously, the GHGs emitted when burning wood.

“By its age, the strain demonstrated the concept of carbon sequestration in this way,” says Mr. Poisson.

The study of Science estimates that this method – burying wood in clay – could remove up to 10 gigatons of GHGs (in CO equivalent) from the atmosphere₂) per year. All at a cost ranging from US$30 to US$100 per tonne, which is competitive with current CO taxes.₂. This represents more than 15% of global annual human GHG emissions.

What about lumber?

Wood also sequesters CO₂ atmospheric when used for the construction of tall buildings. But Ning Zeng did not take lumber into account in his calculations. He admits that his assessment is “maximalist” (high level estimation). And therefore, the “wood vault” approach could have an impact less than 10 gigatons per year.

Mr. Poisson believes that burying the wood in clay could avoid a lot of burning.

The agronomist adds that a lot of wood rots or is burned in Quebec. “Near our waterways, there are a lot of willows and maples in Giguère which don’t really have any market value. And in dams in the Far North, often the driftwood captured by the reservoirs is too far away to be used by sawmills. »

According to Mr. Poisson, there are a lot of clayey soils, composed of clay, in the St. Lawrence valley. The wood would therefore not need to travel far before being buried, he adds.

Patrick Bonin, climate manager at Greenpeace Canada, is more circumspect regarding the discovery of the thousand-year-old strain in Montérégie. “We are talking about a stump in one place. We need to see if this is confirmed elsewhere and in the longer term, and assess the costs of landfilling. A solution presented as miraculous should not distract us from the need to reduce GHG emissions from fossil fuels. »