For builders working with mass timber, a new tool helps to find out exactly how much carbon these structures are emitting.
Developed for the new Portland, OR airport terminal that features an innovative use of mass timber, the University of Washington’s Applied Research Consortium’s new tool called UpStream solves a big question for builders.
“We were trying to understand upstream carbon dynamics of mass timber—going back to the forest and connecting everything,” said Jacob Dunn, a principal with ZGF which built the new terminal. He said the UpStream spreadsheet tool integrates carbon impacts from forest management into life cycle analyses (LCA) and allows for custom end-of-life scenarios for wood products.
The challenge, Dunn explained in an interview, was how to quantify carbon in forests properly and attribute it to wood products. “ZGF identified two key issues: Many end-of-life scenarios aren’t modeled at all, and when they are, there’s an assumption of biogenic carbon neutrality. This assumes that as long as the forest regrows, carbon emissions from wood in landfills or incinerators will be offset by tree regrowth.”
In the interview, Dunn said, “The tool’s basic approach involves calculating the carbon sequestration in a forest over time and dividing that by the amount of wood harvested. Using both observed satellite data and NASA resources, the team measured how much biomass had grown on specific lands over the past 30 years. Satellite tools like lidar could analyze forest growth on a per-pixel basis, tracking changes in carbon stocks across small or large tracts of land.”
Image: ZGF.com
