Life-Cycle Analysis of Redwood Decking

Forest Products Laboratory (FPL) scientist Rick Bergman recently led a life-cycle assessment study of redwood decking in the United States. In cooperation with the Consortium for Research on Renewable Industrial Materials (CORRIM), the School of Environmental and Forest Sciences, University of Washington, and Humboldt State University, Department of Forestry and Wildland Resources, researchers compared the use of redwood with three other decking materials.

Fig_01

Complete life cycle from regeneration of trees to disposal of wood materials

Life-cycle inventory (LCI) and life-cycle assessment (LCA) are terms we’ve been hearing around FPL in recent years with increasing attention to “green building” practices. The term life cycle connotes a fair, holistic assessment to consider all aspects of the product: raw-material production, manufacture, distribution, use, and disposal, including all intervening transportation steps.

The goal for Bergman and his fellow researchers was to conduct an LCI of California redwood (Sequoia sempervirens) decking that would quantify the critical environmental effects of decking from cradle to grave. Using LCI data, the scientists produced a life-cycle assessment for redwood decking. These results were used to compare the environmental footprint of redwood decking to similar decking materials made of plastic (cellular PVC) and wood–plastic composites.

Results of the study showed the total energy expended for redwood was substantially lower than that for the other decking products. The ranking for redwood decking was the result of the product’s ability to store carbon, originally sequestered from the atmosphere, over the life of the product.