All roads lead to wooden cities


As I write this column, four billion people are city dwellers. This represents over half of the world’s population, almost 70% of which is projected to live in urban areas by 2050. The climate change that we have already witnessed in the weather across the world in summer 2023 will strengthen the pull of large population centres.

IN FINLAND, this means that more and more people will live in the Helsinki metropolitan area and in our university towns, increasing our urbanisation rate to 79 percent by 2050.

URBANISATION CREATES a need for new construction, which unfortunately comes at the expense of forests. What does this all mean for carbon sinks? Housing and construction represent over one third of the world’s carbon dioxide emissions, and we need forests to absorb carbon to balance out the equation. To an increasing degree, the environmental impact of the built environment lies in the emissions generated by the actual construction process.

THE SOLUTION could be as simple as mostly using solid wood to build new areas, which would put the carbon stored in forests into temporary, but long-term, carbon storage. Solid wood elements are also extensively recycled. Aalto University has recently issued a study where researchers present a new method for retaining the carbon storage of the forests lost to urbanisation in newly constructed areas. Given the average estimated population density in new areas, wood construction should be at least 30 percent of total construction to store the same amount of carbon.

LAST YEAR, researchers at the Potsdam Institute for Climate Impact Research proposed to house future city dwellers in medium-sized, 4 to 12 storey wooden apartment buildings to store as much as 100 million tons of carbon. This would already be a considerable head start in combating climate change.

OF COURSE, both studies point out that these scenarios will also require responsible and sustainable forest management. Careful, scientific planning is required to protect natural diversity in forests as commercial forestry operations increase. This planning must also be accompanied by sustainable urban development. Since wood is the world’s only renewable, industrial-scale building material, wooden cities are an obvious and relatively easy option to fight climate change.

FINLAND CAN BE a pioneer in net-positive building solutions, with wooden construction, carbon-neutral energy solutions, and entire wooden cities for future-proof carbon storage as our trump cards. In fact, urbanisation can even serve the greater good if we use solid wood for the built environment. We don’t need any new technology or innovations as the technology already exists. We only need to change our attitudes and use wood responsibly.

Read the article in Finnish here.


Mikko Leino is a partner and technology director at Puurakentajat Group Oy.