Developing a dynamic life cycle greenhouse gas emission inventory for wood construction for two different end-of-life scenarios

Abstract

Static life cycle assessment does not fully describe the carbon footprint of construction wood because of carbon changes in the forest and product pools over time. This study developed a dynamic greenhouse gas (GHG) inventory approach using US Forest Service and life-cycle data to estimate GHG emissions on construction wood for two different end-of-life scenarios. Biogenic and fossil GHG emissions sources included a growing forest, logging slash, softwood lumber manufacturing, residue decay and combustion, and product in the landfill. The two scenarios focused on 1) disposing of old wood and logging forests for new construction wood and 2) reusing the old construction wood instead of making new and landfilling the old wood. GHG emissions covered a 100-year time-period and were allocated to 1.0 m³ of softwood lumber produced for two different forests and harvesting rates. Reusing old construction wood had lower GHG emissions initially. However, using new wood would eventually have lower GHG emissions because logged forests regrow and absorb carbon faster and for a longer time than unlogged forests. The paper shows the critical time delay in forest carbon re-accumulating from logging forests may be problematic in mitigating climate change in the short-term but unlikely in the long-term.

Citation

Bergman, Richard D.; Salazar, James; Bowe, Scott. 2012. Developing a dynamic life cycle greenhouse gas emission inventory for wood construction for two different end-of-life scenarios. In: International Symposium of Life Cycle Assessment and Construction, 2012 July 10-12, Nates, France. pp. 318-325.