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 | Mar 12, 2020
Design guide for sloped glazing and skylights updated for first time in 30 years
Helps with choosing proper glass for non-residential applications.
Codes and Standards | Mar 11, 2020
Two tree species native to the Northeast found suitable for CLT
Eastern white pine and eastern hemlock pass strength testing.
Codes and Standards | Mar 10, 2020
Prescient receives ICC certification for seismic resilience system
Technology suitable for buildings up to 12 stories in earthquake-prone areas.
Codes and Standards | Mar 6, 2020
Design firms creating plans to re-imagine D.C.’s tidal basin
Area including National Mall is facing increased flood risk.
Codes and Standards | Mar 5, 2020
France to mandate all new public buildings be 50% timber or other natural materials
Measure would go into effect by 2022.
Codes and Standards | Mar 4, 2020
American Concrete Institute and Precast/Prestressed Concrete Institute expand partnership
Will collaborate on new code requirements.
Codes and Standards | Mar 3, 2020
Wallcoverings industry releases product scorecards concerning sustainability
Tool adds more transparency to certification.
Codes and Standards | Feb 28, 2020
Bay Area communities struggle with what to do about rising sea level
Policies include sea walls, levies, and relocation.
Codes and Standards | Feb 27, 2020
Cell phones present a safety hazard at job sites
Use of ear buds, headphones banned by some contractors.
Codes and Standards | Feb 26, 2020
American Concrete Institute releases 2020 codes, specifications, and practices
ACI Collection features guidance on structural concrete construction and rehabilitation.
