Forestami is a project started in 2018 thanks to a research by Politecnico di Milano, to plant 3 million trees by 2030 in the Milan Metropolitan Area (MMA). Accessibility, inclusiveness, and sustainability are key principles guiding this urban forestry project. To face this territory's physical, environmental, and cultural challenges in the climate change scenario, the project aims to imagine a new “ecological way” of thinking oriented towards a collective effort through the continuous engagement of private and public parties. Since its beginning, Forestami has developed 63 tree plantings in 31 metropolitan municipalities for almost 65,000 new trees and shrubs, developing a new territorial management model capable of structuring the metropolitan green capital. Forestami addresses issues related to the urban and peri-urban afforestation in territories where the existing urban fabric is embedded within the sustainable development of the territory by adapting and tailoring each tree planting to its context. In the densest, urbanised and residential areas of the MMA, the project establishes a new relationship between the existing buildings. The space of nature becomes the link to create new connections and define new images of living, also providing a space where people can live and enjoy new green spaces. This contribution aims to describe the role of forestation projects in residential contexts by focusing on the opportunities that a collective process can trigger, describing two case studies realised by Forestami that have sustainably shaped the urban landscape.