Where you see a steel and concrete office building, Bruce Lippke perceives a plume of “emissions of carbon dioxide that had to go into the atmosphere for those structures to go up.”
Lippke, University of Washington professor emeritus, is lead author of a study in the journal Carbon Management showing that four times more carbon dioxide can be removed from the atmosphere during the next century if we substituted some of our steel-concrete construction with sustainably harvested wood. “Every time you see a wood building, it’s a storehouse of carbon from the forest,” said Lippke in a statement.
The key is that, unlike materials that take large amounts of fossil fuels to create, sustainably managed forests are essentially carbon neutral (if managed properly). Growing trees absorb carbon dioxide and store it until the wood burns or decomposes. Regenerating forests offer an ongoing source of building materials and energy. While controversy surrounds new tree plantations–already expanding rapidly at more than double the 4 million hectare/year of the 1980s–the reality is that harvesting from wild forests will continue to diminish as the global demand for wood products outstrips what they can supply, and the environmental costs of logging non-farmed trees climb ever higher in terms of lost species and GHG emissions.
How can wood change the carbon equation? Once energy savings from more forests, biofuels, and high-efficiency wooden buildings are considered, the numbers look good: 3.9 tons CO2 reduced for every oven-dry ton of wood that is used to displace other structural materials.
Elaine Oneil, a University of Washington research scientist and co-author of the study, says the challenge is ensuring wood is used for its most valuable purpose. Long-lived products–such as houses–that can replace energy intensive materials like high grade steel. Lower grade biomass can be burned as fuel. At every step, the article says, using wood beats fossil fuels from a climate perspective.
Still, it won’t be easy to manage such as massive shift to wood products without environmental risks for natural forests and biodiversity. Sweden, through more than two decades of wood energy and taxes on carbon emissions, had made substantial progress toward its own wood-based economy. The U.S., Oniel says, has similar potential.
“We have been [managing] trees in the U.S. for more than 60 years and we now have 50 percent more wood standing in the forest than when we started managing forests in the early ’50s,” she says. “If these same forests are harvested and reforested, then that cycle completes itself.”
[Image: Flickr user decade_null]