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 | Nov 26, 2018
All LEED-certified buildings eligible for LEED recertification
Projects must submit 12 months of data demonstrating continued or improved performance.
Codes and Standards | Nov 20, 2018
OSHA publishes updates to crane operator certification requirements
Long-delayed rules accept certifications by type or type and capacity.
Codes and Standards | Nov 19, 2018
Guide offers understanding of elements that create successful multi-floor communal spaces
CTBUH technical document analyzes how to approach tall urban habitat.
Codes and Standards | Nov 16, 2018
2018 International Green Construction Code released
Updated version helps governments streamline code development and adoption.
Codes and Standards | Nov 15, 2018
New versions of DOE’s EnergyPlus engine and the OpenStudio software development kit released
New offerings resolve over 70 bugs and offer new features.
Codes and Standards | Nov 14, 2018
Obsolete safety standards may have been used in cleanup of former naval shipyard
San Francisco redevelopment site work may have been racked by fraud.
Codes and Standards | Nov 13, 2018
New York City’s new construction safety requirements are delayed
Some contractors say they weren’t ready for ‘massive initiative’.
Codes and Standards | Nov 9, 2018
Cities have multiple strategies to reduce parking requirements
Each community has to find its own mix of solutions.
Codes and Standards | Nov 8, 2018
Denver replaces green roof mandate with cool roof option
Less costly light-colored roofs can cut project costs by about 1.5%.
Codes and Standards | Nov 7, 2018
New report addresses sound transmission of wood-framed assemblies
AWC document provides empirical sound transmission model.