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Trees Are Climate Change, Carbon Storage Heroes

Amy Androff
Forest Products Laboratory
August 11, 2021

A picture of a cabin house tucked away in a forested area.
Trees hold carbon both while they grow and long after they are harvested. This wooden cabin and the trees around it will continue to store carbon until decomposition or fire releases it into the atmosphere. USDA Forest Service photo.

J.R.R. Tolkien, the author of The Lord of the Rings, once wrote, “I longed to devise a setting in which the trees might really march to war.”

When Tolkien imagined trees marching to war, he probably couldn’t have foreseen the reality of how relevant those words would one day be. If climate change is a battle for Earth’s survival, then trees indeed will be a vital army holding the line.

They hold carbon both while they grow and after they are harvested to build the homes of today and tomorrow. To grow, a tree needs water, sunlight, minerals and carbon dioxide. During photosynthesis, a tree will convert these ingredients into sugars that feed it, fueling its growth. In one year, a mature live tree can absorb more than 48 pounds of carbon dioxide, which is permanently stored in its fibers until the tree or wood experiences a physical event that releases it into the atmosphere, like fire or decomposition.

A picture showing several working in hard hats and orange vests working on a small motor vehicle bridge platform made out of wood.
Adding nanocellulose to concrete can significantly reduce CO2 emissions and create a stronger, more lasting product while storing carbon. This bridge in California is being constructed from cellulose nanocrystal-infused concrete. Photo by Michael Goergen, U.S. Endowment for Forestry and Communities.

It’s hard to talk about how wood products store carbon without reviewing the process that assesses the impact of a product’s carbon storage capacity versus the carbon cost of its creation.

A journal article co-written by Forest Products Laboratory (FPL) researchers explains the use of an internationally-accepted measurement standard called Life Cycle Assessment (LCA). It maps the life of a product holistically from birth to death, or cradle-to-grave, and analyzes and quantifies how much of an environmental impact or burden a product will have on the planet from its extraction, manufacture, use and disposal. Additionally, LCA can equate how much carbon is stored versus produced during a product’s manufacture.

Through the use of LCA, researchers found that with sustainable forest management, forests and wood products storing carbon will have the greatest potential to lessen climate change impacts. LCA studies also found that cross-laminated timber buildings have a lower environmental footprint (especially from greenhouse gas emissions) and store more carbon than buildings constructed from non-timber materials.

Regardless of cut size, wood stores carbon, even at the microscopic scale. For example, nanocellulose is made by breaking wood or plant fibers down to nano-scale rods and filaments. Nanocellulose can be produced sustainably, has a low environmental impact, and is biodegradable. Adding nanocellulose to existing products like concrete or plastic can reduce carbon emissions because nanocellulose has been shown to make materials and products perform better, so less material is needed to do the same job.

A graphic showing the circular life cycle assessment relationship between Resources, Processing, Manufacturing, Distribution, Use and End of Life.
Did you know that the Life Cycle Assessment is an international standard that captures the environmental impact of a given product from birth to death?

For example, cement, an ingredient of concrete, is the third-largest industrial source of air pollution. Adding trees as a concrete additive can significantly reduce CO2 emissions and create a stronger, more lasting product while storing carbon. 

From constructing tall buildings to enhancing materials at the microscopic scale, wood products of any size can have big, positive environmental impacts in the fight to limit climate change.

Tolkien’s heroic tree character Treebeard said, “The world is changing: I feel it in the water, I feel it in the earth, and I smell it in the air.”

Climate change is the greatest challenge of our generation. But the trees are here to fight with us—to build a greener future together.