The city of Helsinki recently commenced a study to estimate the effects of construction, given a scenario of 370 000 new residents moving into Helsinki Region by 2040. The study focused on population density and its consequences, especially forest loss and the subsequent loss in carbon storage formed by trees to be removed. However, the study ignored the choice of construction material, which plays a tremendous role in the creation of urban carbon storages.

In fact, mass timber construction will create an urban carbon storage on the construction sites in the form of buildings, even though forest is lost due to conversion of forestland into construction. The volume of the urban carbon storage can be estimated and evaluated based on a model developed by Dasos. Depending on the density of the urban building structure, the urban carbon storage created is 4 to 25 times larger than the carbon stored in the trees on the construction sites. A typical forest in the Southern Finland would grow back the carbon stored in the houses in 12 years.

For more information please see https://www.maaseuduntulevaisuus.fi/metsa/8517bbbb-061b-4426-877d-0e4681baf768 and https://www.hs.fi/kaupunki/art-2000009090283.html