Many human activities such as driving automobiles and heating homes typically add climate-changing carbon dioxide (CO2) and other greenhouse gases to the atmosphere. Using wood for home construction, instead of more energy intensive building products, can actually help offset CO2 contributions.
Analysis conducted by Weyerhaeuser's iLevel wood products business demonstrates that its products store from 7 to 24 percent more carbon over their useful lives than is emitted to produce them. iLevel wood products manufactured in 2008 stored the equivalent of 7.7 million metric tons of CO2 - comparable to taking 1.4 million cars off the road. www.ilevel.com
The benefit results from the natural process of photosynthesis, in which growing trees absorb CO2 from the air and break it into carbon and oxygen molecules. Trees release the oxygen back to the air, and combine the carbon with other building blocks to form wood fiber. After harvest and manufacture into building products, the carbon remains in wood for the life of the building and beyond.
The volume of CO2 stored in iLevel products such as TimberStrand® laminated strand lumber (LSL), Parallam® parallel strand lumber (PSL), Microllam® laminated veneer lumber (LVL) and iLevel® oriented strand board (OSB) exceeds the CO2 emissions from growing, harvesting and manufacturing them by approximately 40 to 140 kilograms per metric ton. The analysis accounts for all greenhouse gases emitted through manufacture, and is expressed as a CO2 equivalent following standard methods.
"Wood is unique among structural building materials in its ability to remove carbon from the air and store it long term," says Edie Sonne Hall, Manager, Sustainable Forests and Products, with Weyerhaeuser. "Wood takes relatively little energy to manufacture, as most of the 'manufacturing' is done by the sun through photosynthesis."
In addition to helping offset greenhouse gases in the atmosphere, iLevel makes efficient use of natural resources. The business uses an average of 99 percent of every log in its manufacturing processes. Overall, the Weyerhaeuser company plants more than 100 million seedlings each year, and 100 percent of the forests it owns or manages in North America are independently certified to sustainable forestry standards.