Forests: Nature’s Building Material Factories

The case for Cross Laminated Timber as a sustainable building material

by Ed Gulick
June 17, 2019

“Use lots of wood in building? No way—I’m a green architect!” That was my sentiment when I was a design student and beginning my architectural career. If late 1990s Ed were to pay me a visit, I suspect he would be aghast that I will be presenting at something called the Montana Mass Timber Rising conference.

And yet I’m thrilled at the prospect of using lots of wood in large slabs called Cross Laminated Timber in an upcoming project! Here are the reasons:

1. Environmental: While I once viewed lumber use as environmentally problematic because I didn’t want to cut forests down, I’ve come to recognize that wood has a number of environmental benefits compared to other structural materials like steel and concrete. In fact, I think forests are like nature’s factories for producing the ideal green building material. When manufacturing wood, these natural factories:

   • Are 100% solar-powered. No fossil fuels are used in nature’s manufacture of wood mass. Yes, they are used in the harvesting and processing of wood, but overall there is a 50-100% reduction in embodied energy when comparing wood to steel and concrete in a comparable application.

   • Sequester carbon. Using lumber in buildings actually sequesters CO2 that trees harvested from the atmosphere. As we continue to drive down the carbon intensity to operate our buildings, we also need to be driving down the embodied carbon intensity of the materials that make up our buildings.

   • Provide ecological services. At the same time that forests are manufacturing wood, they are also providing habitat, shade, and watershed benefits. Many of the ecological benefits don’t occur with forest management practices that are still common, such as clearcutting. However, certification programs like those of the Forest Stewardship Council can ensure that forests that are managed for habitat and other ecological benefits, but one needs to specify wood accordingly.

2. Local Material: Using local materials connects a building to place and makes it more meaningful. The Cross Laminated Timber (CLT) that we’re planning on using in an upcoming project comes from SmartLam, one of two CLT manufacturers in the U.S. SmartLam is located in Columbia Falls, near the northwest corner of Montana, while our project will be in south-central Montana., so there is less transportation energy required than many other materials. The local benefit also is economic, with the money going to SmartLam recirculating in Montana, paying for secondary and tertiary jobs as opposed to importing materials from out-of-state.

3. Biophilia: Humans have an innate affinity for nature. We are drawn to natural places. We are happier, less stressed, and healthier when we have contact with nature in various ways, including the patterning in minimally processed natural materials. We plan to leave the CLT panels exposed at the ceiling in our upcoming project, so the natural wood grain will be visible. Building occupants benefit from the complex, non-repeating patterns of this wood grain.

Stay tuned to find out what I learn at this conference. Having not yet completed a project with CLT or other similar mass wood products, I expect to learn far more than I impart at this event. I’m looking forward to the day I become a master with CLT. People will ask: “How do I create a net-zero energy building with CLT?” And I will say: “Ah, watch and learn, Grasshopper…”