Inside Innovation: Unravelling MTC’s sustainability and life cycle analyses claims

By / John Bleasby 

Mass Timber Construction (MTC) is touted as construction’s wonder material. It’s sustainable, renewable, light and easy to assemble, and attractive, say its promoters. Life Cycle Analyses (LCA) investigating GHG emissions appear to overwhelmingly favour wood over concrete and steel. Even the recent doubling of wood prices has not dampened enthusiasm for its use in ever-larger construction projects.

Wood is good and many MTC claims are true to a certain degree. However, perhaps it’s time to dial down some of MTC’s exuberant rhetoric. 

First, let’s take a look at MTC’s sustainability claims.

Trees and oceans together absorb 50 per cent of global atmospheric carbon. However, once a tree is forested, it can no longer capture carbon — at best it can only store what is already there. Reforestation is critical, of course, however a seedling is a poor substitute for an old growth tree. It will take decades for a seedling to reach the mature height of its predecessor.