In the megacities that are home to nearly 10 percent of the world's 7.5 billion people, trees provide each city with more than $500 million each year in services that make urban environments cleaner, more affordable and more pleasant places to live.
In a recent study published in the online journal Ecological Modelling, an international team of researchers reported that in the 10 megacities they studied, tree-based ecosystem benefits had a median annual value of $505 million, which is equivalent to $1.2 million per square kilometer of trees. From another perspective, the value was $35 per capita for the average megacity resident.
The study's lead author, Dr. Theodore Endreny of the College of Environmental Science and Forestry (ESF) in Syracuse, New York, said the value of trees' services could easily be doubled by simply planting more of them.
"Megacities can increase these benefits on average by 85 percent," Endreny said. "If trees were to be established throughout their potential cover area, they would serve to filter air and water pollutants and reduce building energy use, and improve human well-being while providing habitat and resources for other species in the urban area."
The study estimated existing and potential tree cover, and its contribution to ecosystem services in 10 megacity metropolitan areas across five continents and biomes (a large, natural community of plants and animals that occupies a major habitat). The cities were Beijing, China; Buenos Aires, Argentina; Cairo, Egypt; Istanbul, Turkey; London, Great Britain; Los Angeles, United States; Mexico City, Mexico; Moscow, Russia; Mumbai, India; and Tokyo, Japan.
Read more at ESF - State University of New York
Image: Environmental Science and Forestry (ESF)