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 | May 1, 2015
Department of Energy asks for feedback on cost-effectiveness of building energy codes
DOE’s RFI wants input on how to improve methodology on cost assessment.
Codes and Standards | Apr 22, 2015
New York State renews design-build authority
Five state agencies are allowed to use design-build on certain projects.
Codes and Standards | Apr 22, 2015
OSHA’s estimated cost of silica rule said to underestimate impact by $4.5 billion annually
The coalition says that OSHA’s flawed cost estimates point to flaws in the rule, and has urged the federal agency to reconsider its approach.
Codes and Standards | Apr 22, 2015
2016 Seismic Provisions for Structural Steel Buildings draft available for public review
The comment period is open until May 29.
Codes and Standards | Apr 22, 2015
GBCI renamed Green Business Certification Inc.
The name change reflects the organization’s expanded certification and credentialing services.
Multifamily Housing | Apr 16, 2015
Seattle’s size restriction on micro apartments blamed for rise in rents
Seattle’s city planner recently said that the council’s new rules have made small apartments more expensive to build and charged the board with “overreaching” and not giving micro-housing “a fair shake.”
Green | Apr 16, 2015
New version of Building Energy Data Exchange Specification launched
BEDES is a dictionary that facilitates consistent exchange of building characteristics and energy use data between tools and databases in the building energy efficiency sector.
Codes and Standards | Apr 16, 2015
New York tops U.S. cities in walkability
Revitalization pushes Detroit and New Orleans up the rankings
Green | Apr 14, 2015
USGBC will recognize energy and water standards for the Living Building Challenge
This move means that projects achieving the energy and water requirements in Living Building Challenge will be considered as technically equivalent to LEED.
Codes and Standards | Apr 14, 2015
New York City preparing new codes for evacuation elevators
New York City’s Fire, Buildings, and City Planning Departments in New York are writing rules to govern occupant-evacuation elevators, reflecting a change in philosophy of how to evacuate people from skyscrapers in an emergency.