Bosco Verticale, Milan

Bosco Verticale, from the adjacent Biblioteca Degli Alberi Park. Image credit: COIMA

Does this mean Bosco Verticale’s breath-taking green coat and the associated enhanced building operational performance provided are a beacon of sustainability? Not entirely so, from an embodied carbon perspective or a social vantage point.

The added weight and wind resistance generated by the vegetation has made it necessary to use pre-stressed concrete to build each of the cantilevered terraces. This means that additional building materials were used in the construction and therefore added to the embodied emissions and natural resources required to achieve the benefits outlined above.

As awareness around lifecycle emissions resulting from buildings has evolved, so has the exploration of alternative construction materials and other technical solutions to reduce the cantilevered structure and loads to maintain the operational benefits of vertical forest projects, whilst reducing embodied carbon emissions. For example La Forêt Blanche in Paris, France, is conceived entirely with a mixed wood-steel structure to support 400 trees. If implemented, this project (currently at conceptual stage) would reduce the whole life emissions impact of the building by using lower upfront carbon materials in the form of sustainably sourced timber.