The Woodsman: Can’t C the Forest for the Carbon
By Steve Wilent
A few years ago a forester friend said that the best way to capture carbon dioxide, or CO2, from the atmosphere and store it permanently would be to harvest lots of fast-growing trees, such as cottonwood, Douglas-fir, loblolly pine, or eucalyptus, and sink them in the deepest parts of the oceans. Wood is about half carbon (C) by weight. The cold salt water, he said, would prevent the logs from decomposing, thus sealing away the carbon in the wood forever. Plant more trees and repeat.
That would help slow down climate change, he opined, and might even create some new fish habitat.
Another forester chimed in with a different take: Although Forester No. 1’s plan would indeed store carbon away beneath the waves, the scheme addresses only part of the problem. It would be far better, said Forester No. 2, to use those fast-growing trees to make products that are substitutes for materials that result in carbon dioxide emissions during their manufacture (such as concrete and steel) or combustion (coal, oil, natural gas, propane, jet fuel).
I agree with Forester No. 2. According to a February 2023 article in Scientific American, cement and concrete production generates as much as nine percent of all anthropogenic (human-caused) CO2 emissions (the article “Solving Cement’s Massive Carbon Problem” describes efforts to address the issue). The production of steel results in another eight to 11 percent of global CO2 emissions, according to multiple sources. The burning of fossil fuels for generating heat and power produces about one-quarter of CO2 emissions, according to the US Environmental Protection Agency.
Cross-laminated timbers (CLTs) — beams and panels made of lumber glued together — and mass plywood panels (MPP) — think plywood on steroids — are excellent substitutes for concrete and steel walls, floors, ceilings, columns, and beams. Much of the revamped Portland International Airport terminal, scheduled to debut this year, is built from CLTs and MPPs made from trees harvested in Oregon and Washington. Using wood products not only avoids the emissions released in producing concrete and steel, but CLTs and MPPs store carbon absorbed from the atmosphere by trees.
Nonetheless, some people continue to promote the idea of sinking wood in the oceans or burying it underground. Cases in point: “Will sinking tonnes of wood into the ocean help tackle climate change?” (New Scientist, August 9, 2023) and a November 28 article in the Wall Street Journal, “The Newest Airline Climate Solution? Burying Sawdust.”
The latter article explains that American Airlines is working with Graphyte, a startup company that collects sawdust and other forest and agricultural waste products (also known as biomass), dries it, and forms it into “shoebox-size bricks and seals it using a special barrier to prevent the plant matter from decomposing and releasing carbon. The bricks are then buried and monitored using an embedded tracer substance to ensure they are locking away carbon.”
Graphyte’s first facility is in Pine Bluff, Arkansas, where it collects waste products from two lumber mills and a rice-milling operation to produce what it calls “carbon blocks.” (For what it’s worth, Graphyte’s blocks look very similar to the fire bricks made for wood stoves by Bear Mountain Forest Products, of Cascade Locks.)
According to Graphyte, this is “the world’s first and only carbon dioxide removal solution that is permanent, affordable, and immediately scalable.”
In my opinion, Graphyte’s intent is noble, but misguided. Burying the biomass bricks does seal away the carbon, but the using of the biomass as substitutes for fossil-fuel-intensive products would be much more effective. Could the carbon blocks be used to build houses? Maybe. Could the biomass be made into wood pellets to be used as a substitute for coal? Yes. Instead of making carbon blocks, the wood waste could be converted into a variety of useful products, such as paper, fabrics, and thermal insulation products that are substitutes for fiberglass or spray foams.
And so on. It’s a shame to simply bury them. I wonder if a big carbon block would make a good night log. I wonder if American Airlines would pay me to burn carbon blocks in my woodstove…
Have a question about the carbon in trees? Want to know where to buy a 16,800-pound carbon panel? Let me know. Email: SWilent@gmail.com.