ITHACA, N.Y. - Researchers have created an interactive map identifying 1.8 million individual trees in New York City, with a new approach that could optimize the placement of trees for cooling in cities around the world.
In the study, published in Scientific Data , researchers from Cornell University identify the types of trees using satellite imagery as well as on-the-ground datasets and 3D data collected with lidar. The approach was 82% accurate overall, with even higher accuracy for common types of New York City trees.
It's the first "wall-to-wall," citywide map identifying trees, and it includes trees on private property, in natural areas and other unsurveyed areas, which together constitute an estimated 65% of the city's canopy and have not been accounted for on previous maps. The research team will use the map to determine which trees are best for cooling, and the data could inform a host of other planting decisions where the type of tree makes a difference, from reducing allergens to managing invasive pests.
"If we're going to be managing these urban forests well, we need to know what's there, and now we know that for another 1.4 million trees beyond the street trees that were already surveyed," said Daniel Katz , a senior author and assistant professor in the School of Integrative Plant Science.
The research is part of the Cool Trees project, led by co-author Dr. Arnab Ghosh , associate professor of medicine at Weill Cornell Medicine. An unrelated Cornell project, "The Generative Canopy," aims to leverage street-tree data to determine where more trees are needed to provide shade to vulnerable New York City residents.
The city recently set a goal of expanding tree cover from 22% to 30% by 2040, and the new map could directly inform those efforts.
"We'll be able to say: If you make this planting or management decision about a tree, here's how it'll affect temperature and here's how it will affect the number of people going to the emergency room during a heat wave," said Katz, a co-investigator with Cool Trees. "That's really powerful."
Katz said they hope to apply their approach to many more locations; the team has compiled a database of 405 medium and large U.S. cities they hope to map.
Katz said he hopes making the data available and user-friendly for planners, researchers and the public will also expand its impact.
"This is science for the public good, so it was important for us to make it available," Katz said. "We think a lot of others will have ideas for how to use this map, and we hope people have fun with it, too."
Funding for the research came from the USDA's National Institute of Food and Agriculture, the Cornell Atkinson Center for Sustainability and the Leona M. and Harry B. Helmsley Charitable Trust.
