Granite Geek

How trees can best cut carbon: Don’t just replace oil, replace steel & concrete

Apr. 18, 2018

Science Cafe NH in Concord last night had a great discussion about the environmental aspects of using wood to create heat and electricity (sometimes bad, sometimes good – like so much in life). The video will be posted in a week or two, after editing is done, by Concord TV.

The conversation took an interesting turn, however, when one of our panelists, Robert Perschel of the New England Forestry Foundation, pitched NEFF’s “Build it with wood” program, which is trying to get people to build mid-rise buildings with cross-laminated timber. You may remember seeing my column about it in January.

Making good sawlogs requires large, mature trees, but CLT timber can be made by gluing together boards from smaller trees, thus increasing the value of a timber lot. From the point of view of fighting climate change, building with wood is at the top of the list, Perschel said, for two reasons: one, it takes the carbon in the wood and locks it away for the life of the building, whereas burning it for power releases the carbon immediately; two, it can replace steel and concrete, which are both carbon-intensive things to make (especially concrete).

CLT is growing in popularity in Europe but is hardly used in the U.S., except for a couple of buildings, including one at UMass-Amherst. But two Maine mills are being refitted to make CLT timbers, so perhaps that will change.

By David Brooks