Trees offer enormous monetary benefit to megacities, or those urban areas where over 10 million people reside. New research led by Theodore Endreny of SUNY’s College of Environmental Studies and Forestry highlights the idea that cities shouldn’t overlook the immense value of these plants: every year they could offer a payoff of $482 million in lowered air pollution, $11 million in stormwater remediation, $8 million in carbon dioxide sequestration, and $500,000 savings on heating and cooling costs.
The researchers looked at Los Angeles, Beijing, Tokyo, Mumbai, Buenos Aires, Moscow, London, Istanbul, Mexico City, and Cairo. They built on estimates from the i-Tree model developed by the United States Forest Service, which analyzes environmental benefits from trees, with local data. They found median tree cover in all the cities was 21 percent, with potential tree cover at 19 percent. Tree cover varies by megacity – for example, in Cairo tree cover is just 8.1 percent while in Moscow it’s 36 percent. Tokyo claims the prize for greatest tree canopy cover per person, according to CityLab.
The benefits each megacity reaps from trees varies some as well. Cairo doesn’t receive much precipitation so they don’t benefit that much from stormwater remediation. And Mumbai’s energy expenditures aren’t as high as other megacities’ so it doesn’t benefit as much in that area. Los Angeles got the most benefit from trees sequestering carbon dioxide.
The researchers suggest cities plant more trees to nearly double the benefits gleaned from the leafy canopies. And as nearly 10 percent of humans live in megacities, the move could serve millions of people.
The journal Ecological Modelling made the research available online at the end of July. Six researchers at the State University of New York College of Environmental Science and Forestry and the Parthenope University of Naples contributed to the study.