LIFE CYCLE ENERGY AND ENVIRONMENTAL IMPACTS OF CROSS LAMINATED TIMBER MADE WITH COASTAL DOUGLAS-FIR

In this study, a cradle-to-gate life-cycle assessment (LCA) of Oregon-made cross-laminated timber (CLT) was conducted as per the ISO guidelines. Primary data pertaining to CLT manufacturing was collected from a production facility in Oregon and modeled with existing LCA data of Pacific Northwest softwood lumber production and harvesting operations. Primary energy is reported and encompasses all processes within the system boundary. Carbon emissions are reported and include fossil-based emissions from transportation and all production processes and carbon storage in CLT. LCA results are presented for five impact categories, primary energy consumption, and net carbon impact of CLT. Results show the environmental advantage of CLT due to storing of large amounts of biogenic carbon in a building structure for a lifetime. The amount of carbon stored in CLT offsets the emissions released from all production processes; this indicates that CLT is a net negative carbon emitter, as more carbon is stored in the product than is emitted to produce the product. This study shows the importance of using the LCA methodology for showing the net amount and type of energy used for production and the potential climatic impacts of using wood products. This LCA study makes no comparative assertions.