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 | Dec 18, 2015
Codes should be updated to reflect lessons learned from recent extreme weather events
More can be done to boost resiliency to flooding, extended power outages.
Codes and Standards | Dec 13, 2015
Los Angeles launches ‘Drop 100′ campaign to reduce water use in commercial buildings
Goal is to save 100 million gallons annually.
Codes and Standards | Dec 1, 2015
More than 50 design, construction, and real estate firms urge action on climate change
Call for policymakers to move on one of the ‘greatest economic opportunities of the 21st Century’
Codes and Standards | Oct 26, 2015
Chicago suburb considers bird collision deterrent requirement on all new buildings
The rule would mandate that new commercial, multifamily structures comply with LEED pilot program.
Codes and Standards | Oct 16, 2015
Anchorage may raise building height restrictions that would block precious winter sunlight
Controversial measure is part of plan to spur development.
Codes and Standards | Oct 16, 2015
Appellate court enacts nationwide stay on controversial expansion of Clean Water Act
New EPA rule suspended until court cases settled.
Codes and Standards | Oct 9, 2015
New California law means commercial building benchmarking program will be implemented
Multifamily housing to be included, a first for a U.S. state.
Codes and Standards | Oct 2, 2015
New ASHRAE guideline for commissioning existing systems and assemblies
Focuses on optimum facility and system operation.
Codes and Standards | Sep 18, 2015
New RELi standard addresses disaster resilience
Based on LEED model, may help lower insurance rates
Building Materials | Aug 28, 2015
Structural steel buildings specification available for second public review
Next year's specification open for comments until Sept. 21