The California Redwood Association (CRA) recently enlisted help from the independent Consortium for Research on Renewable Industrial Materials (CORRIM) to conduct a life cycle assessment (LCA) to better understand and compare redwood decking to plastic composite decking. CORRIM is a non-profit research consortium with members from 16 universities and research institutions such as the USDA Forest Products Laboratory. CORRIM has been involved in the field of LCA for well over a decade and is among the most respected institutions performing such work.
Results of the LCA are conclusive, showing that considerable differences exist between redwood and alternative decking products such as plastics and plastic composites. In terms of global warming potential, plastic-based decking materials are contributors, while growing, harvesting and using redwood for decks do not contribute to global warming.
Regarding other important environmental impacts, plastic-based decking contributes anywhere from twice as much to 100 times as much negative effects as redwood. Redwood decks store the carbon that was originally absorbed as CO2 from the atmosphere while the trees were growing. In fact, the average redwood deck may store over half a ton of carbon. Once the redwood deck has reached the end of its lifespan, it is easily recycled or reused for other purposes, or reabsorbed into the earth as nutrients for new plants. On the other extreme are plastic composites, which will stack up for decades in landfills.
Detailed data was collected from CRA member mills on such items as raw material production (harvest), manufacture (energy usage), product distribution (transportation), product installation and use (lifespan), and final product disposal at end of life (reuse vs. landfill).
According to Dean Kerstetter, v.p. of operations for Mendocino Forest Products, “The quantity and detail of information gathered by the CORRIM team was truly amazing. Rick Bergman, CORRIM team member with the USDA Forest Products Lab in Madison, Wi., visited our manufacturing facilities in Ukiah, Ca., for two days collecting detailed data on log storage and handling, type of sawmill equipment, dry kilns, boiler, planer-basically anything that consumed energy.”
Han-Sup Han, professor of forest operations & engineering at Humboldt State University, Arcata, Ca., is the CORRIM researcher who spent days visiting forestlands of CRA member mills throughout the redwood region. According to Professor Han, the forest resource data collection phase of LCA integrates site preparation, stand establishment, stand management, and timber harvest factors associated with forest management into a presentation of total cost, fuel consumption, and carbon footprint for various levels of management intensity.
“The redwood lumber industry has known for years that we have an outstanding environmental record and a great green message to tell consumers,” said Janet Webb, president of Big Creek Lumber Co., Davenport, Ca., and current chair of the CRA. “Operating in accordance with the strict provisions of the California Forest Practices Act places any industrial or non-industrial forest landowner or timber operation at the forefront of environmental responsibility. This new LCA reinforces our beliefs that redwood is a world class product in terms of environmental performance.”