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
Energy Efficiency | Aug 28, 2015
North American Passive House Network e-book explains Passivhaus, net-zero techniques
Free guide includes spotlight on individual projects
Windows and Doors | Aug 28, 2015
Newly formed group challenges Florida building code
Window, door companies oppose provisions that raise costs
Codes and Standards | Aug 28, 2015
New Orleans becoming a model for climate resilience only 10 years after Katrina
The city has moved ahead with resilience strategies that may become a model for other communities
Codes and Standards | Aug 21, 2015
Illinois governor vetoes bill that would restrict condo owners’ rights
Bill would have made it harder to sue for building flaws
Codes and Standards | Aug 21, 2015
Post-Katrina roofing codes creating more resilient buildings on Gulf Coast
Ten years after storm, notable progress on stronger roofs, IBHS says
Smart Buildings | Aug 21, 2015
Federal Alliance for Safe Homes offers plan to strengthen codes for disaster resilience
Some states losing ground on resilience, group says
Codes and Standards | Aug 21, 2015
After disease outbreak, ASHRAE legionella standard adopted in New York
City Council acts after 12 die of legionellosis
Codes and Standards | Aug 13, 2015
Research indicates major earthquake looming for Pacific Northwest
Most structures built before seismic codes instituted; extreme damage predicted
Codes and Standards | Aug 13, 2015
New York City may allow affordable housing developers to ‘double dip’ in subsidies
New York City may allow affordable housing developers to ‘double dip’ in subsidies
Codes and Standards | Aug 13, 2015
L.A. considers controversial traffic calming measures
Goal is to encourage alternative transportation
