Trees Contribute the Wellbeing of Urban Population, Especially in Megacities

More than half of the world’s population live in the cities and the number is undoubtedly rising. The United Nations projects the percentage of the urban population to be around 66% by 2050. The picture is certainly extra distressing for megacities which already host at least 10 million inhabitants. Among many other, the most disturbing consequence of having too many people in a city is the decline in air quality. So, how will we be able to breathe?

A new study conducted by researchers from the State University of New York (SUNY) and the Parthenope University of Naples show the incredible benefits of planting trees and creating urban forestry in megacities. The leading author of the article, Prof. Dr. Theodore Endreny of SUNY told Thomson Reuters Foundation: “Greening urban areas is critical. Trees are immeasurably important for human wellbeing and biodiversity, the underpinning of our quality of life.”

The researches have selected 10 megacities distributed in five continents including Buenos Aires, Istanbul and Los Angeles, all representing different biomes. They used i-Tree Canopy, an online tool estimating tree cover and tree benefits for a given area with a random sampling process. Results show that the potential area for additional tree canopy cover range between 15.6% (Cairo) and 24% (Los Angeles). If trees are planted in these areas, the total tree cover would go up to 85% on average, doubling the benefits.

The benefits of planting trees in metropolitan areas are not merely environmental or social but also economical. Air pollution reduction can save the megacity more than $482 million a year. $107,000 of this is elicited through avoided carbon emissions. The study stated: “The median value of half a billion dollars per year of ecosystem services provided by these trees is an accounting of how nature improves human livelihoods.”

The researchers underlined the urgency to focus on greening the cities instead of treating the urban areas as if they were outside the ecosystem. Trees function as the filter of pollutants, cleaning our air, hence improving our quality of life. Although frequently neglected, urban population can make the most of the benefits.


Endreny, T., Santagata, R., Perna, A., De Stefano, C., Rallo, R. F., & Ulgiati, S. (2017). Implementing and managing urban forests: A much needed conservation strategy to increase ecosystem services and urban wellbeing. Ecological Modelling360, 328-335.

Pujol-Mazzini, A. (2017, August 23). Cleaner air, cooler buildings: urban trees save megacities millions. Thomson Reuters Foundation News. Retrieved from: