Cross-laminated timber, or CLT, is touted as a more sustainable option for building construction than concrete and steel. But is it really? The answer is complicated.
CLT is intended to replace concrete and steel whose production accounts for about 13% of global carbon dioxide emissions. Wood in CLT panels pulled CO2 from the atmosphere, and that carbon should remain locked up as long as the building stands.
Some forest scientists, climate modelers, and materials experts question how much of an environmental net gain results from using CLT to replace concrete and steel. Part of the concern relates to choices the lumber industry makes in forestry practices and manufacturing.
Lots of carbon gets dumped into the atmosphere when logs are transformed into CLT, they say. Sawmills and CLT plants typically burn bark, sawdust, and other wood wastes for heat, releasing carbon. Piles of branches, treetops, and smaller trees left behind after a harvest are often burned or left to decompose—releasing carbon into the atmosphere.
When it comes to combating global climate change, the mantra of “wood is good” may be simplistic.
Related Stories
Codes and Standards | Aug 19, 2021
Massive infrastructure bill includes hundreds of millions for building energy efficiency
Funds allotted for updated code implementation, construction technology, K-12 efficiency programs.
Codes and Standards | Aug 18, 2021
Fannie Mae green bonds program could be greenwashing
Analysis shows significant number of green bond properties become less efficient.
Codes and Standards | Aug 17, 2021
Three Texas cities head list of most environmentally vulnerable
Hazard analysis includes natural disasters and government response categories.
Codes and Standards | Aug 16, 2021
Bill would reform New York’s public contracting process
Council on Public Contracting Reform to have contractor representation.
Codes and Standards | Aug 12, 2021
AGC pushes for more environmentally friendly construction
Contractor trade group supports government investment, tax incentives to reduce carbon footprints.
Codes and Standards | Aug 11, 2021
Decentralized approach to codes means emissions reduction responsibility falls on local officials
Efficiency advocates focusing more on local code amendments.
Codes and Standards | Aug 10, 2021
Dept. of Energy issues model energy code determinations for commercial, residential buildings
2021 IECC offers 9.4% site energy savings.
Digital Twin | Aug 9, 2021
Digital Twin Maturity white paper offers guidance on digital twin adoption
Provides lifecycle map and an approach for incorporating digital twins.
Codes and Standards | Aug 5, 2021
Contractors can be liable for building failures many years after project completion
Personal injury suits could be brought decades after substantial completion.
Codes and Standards | Aug 4, 2021
Mass timber is a natural choice for building recycling through deconstruction
Designing wood buildings to optimize recovery of materials for disassembly aids carbon sequestration.
