Abstract Summary
Urban vegetation – encompassing all trees, shrubs, lawns, and other vegetation in cities –, if adequately managed, can play an important role to ensure a good quality of life and meet the challenges set by Agenda 2030, helping to reach 15 Sustainable Development Goals: indeed, in urban environments it can provide several ecosystem services, such as air purification, global climate regulation, temperature regulation, run-off mitigation as well as recreational opportunities, increasing aesthetic values. In a few words, urban vegetation can help make cities safer, healthier, wealthier and more attractive, with benefits grouped in social, communal, environmental and economic categories. This key role is now being threatened by climate change impacts and extreme weather conditions, that limit urban vegetation lifespan and so its ability to provide ecosystem services. Among other cities worldwide, a clear example of this can be seen in Milan, Italy. Indeed, last July, the city has been hit by a tremendous storm - strong winds over 100 km/h, more the 40 mm of rains in just 10 minutes - causing huge damages and losses to the city, including the urban vegetation (high percentage of trees down). We have been called to quantify and assess this vegetation loss, and propose compensation actions. In doing that, we proposed and are now applying a new methodology to first screen the damages, and then to quantify the environmental loss. The methodology encompasses two layers: a field one, to collect punctual data (e.g., species and dimension of the damaged trees) and a analytic one, leveraging on European Space Agency images, to evaluate the difference before and after the storm in terms of tree coverage, with a resolution of 50 cm. This procedure helped to clarify most hit areas within the city, counting the tons of Carbon no more stored in the trees and other lost ecosystem services, and it has been useful now to properly plan new urban forests around the city, setting clear and verifiable goals in term of tree cover, helping the city to recover. Therefore, from a negative event and incredible loss, thanks to this innovative approach, Milan is now ready to reshape its urban greenery and to become more sustainable than before. The same methodology can be applied to new neighborhood or building projects, to keep track of urban greenery changes and benefits.
