Architects, builders, and sustainability advocates are all abuzz over a new building material they say could substantially reduce greenhouse gas (GHG) emissions in the building sector, slash the waste, pollution, and costs associated with construction, and create a more physically, psychologically, and aesthetically healthy built environment.

The material is known as, uh, wood.

Trees have been used to build structures since prehistory, but especially after disasters like the Great Chicago Fire of 1871, wood came to be seen as unsafe and unstable relative to the two materials that have since become staples of the construction industry worldwide: concrete and steel. However, a new way of using wood has put the material back in the spotlight. The hype is focused on structural timber or, as it’s more popularly known, “mass timber” (short for “massive timber”).

In a nutshell, it involves sticking pieces of softwood — generally conifers like pine, spruce, or fir, but also sometimes deciduous species such as birch, ash, and beech — together to form larger pieces. Yes, the hottest thing in architecture this century amounts to “wood, but like Legos.”

If you’re worried about the potential fire hazard that comes with using timber as a building material, don’t be. These solid, compressed masses of wood are actually quite difficult to ignite. In the case of fire, the outer layer of mass timber will tend to char in a predictable way that effectively self-extinguishes and shields the interior, allowing it to retain structural integrity for several hours in even intense fire.

With its environmental and aesthetic advantages, expect to be seeing more buildings made using timber over the coming years.