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 | Jan 9, 2017
China claims top ranking outside of U.S. for total LEED-certified space
Canada, India, Brazil, and Korea round out top 5.
Codes and Standards | Jan 6, 2017
OSHA prompts more proactive approach to construction site safety
Remote operated camera systems are being used to mitigate risk in real time.
Codes and Standards | Jan 5, 2017
2018 building energy code upholds efficiency gains
Efforts to scale back efficiency requirements largely defeated.
Codes and Standards | Jan 4, 2017
Low-income housing doesn’t lower neighborhood housing values
A Trulia study contradicts longstanding fears.
Codes and Standards | Jan 3, 2017
Intelligent transportation systems have implications for designers, construction firms
Sensors and Internet of Things devices will have to be embedded in infrastructure.
Codes and Standards | Dec 15, 2016
OSHA releases safety recommendation guide for construction industry
It is said to be most helpful to small and mid-sized contractors.
Codes and Standards | Dec 14, 2016
Cities must invest $375 billion to avoid catastrophic global climate change
C40 Cities Climate Leadership Group advocates low carbon infrastructure.
Codes and Standards | Dec 14, 2016
Resilient construction techniques pay for themselves over lifetime of buildings
Spending $340,000 for resiliency would pay for itself over the lifetime of a $10 million structure.
Codes and Standards | Dec 12, 2016
Dept. of Energy launches program to advance zero energy school design
Six school districts and two states are among the first to mainstream zero energy schools.
Codes and Standards | Dec 9, 2016
California city’s plan for net zero building includes net zero water usage
Santa Monica city services building aims for highest level of sustainability.
