Global changes (GC) is increasingly threatening the green infrastructures of our cities, especially trees and its associated vegetation. In fact, these are more and more affected by increased environmental stress levels, insects and exotic diseases. These trees provide, directly and indirectly, as a part of an urban terrestrial ecosystem functioning, numerous ecosystem services which are essential to our well-being. These services are in danger of being significantly reduced in response to growing threats caused by GCs. The underlying hypothesis of this project is that the resistance and resilience of urban and suburban ecosystems, and consequently the ecosystem services which are provided, can be strengthened by favoring a greater structural diversity of ecosystems, a greater functional diversity of trees and associated vegetation and a greater connectivity between green spaces in response to the GC and associated predictions for southern Quebec over the next few years. We will work in Montreal, Ottawa/Gatineau and Quebec City in order to plan biodiversity corridors, to measure flows of ecosystem services and to make an economic evaluation.