This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers have created an interactive map identifying 1.8 million individual trees in New York City, using 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 identify the types of trees using satellite imagery, on-the-ground data sets and 3D data collected with lidar, short for light detection and ranging.
The approach was 82% accurate overall and more accurate 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 in the College of Agriculture and Life Sciences. "We can now use this information to make sure we get the most benefits from trees, from cooling to reducing air pollution and flooding. We also hope people will enjoy looking at their own neighborhood and seeing which trees are around them." The research is part of the Cool Trees project, led by co-author Dr.
Arnab Ghosh, M.S. '19, '23, associate professor of medicine at Weill Cornell Medicine. Optimizing trees' cooling effects is increasingly important as heat waves in New York City become more frequent and intense. 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, along with broader research from the Cool Trees team to determine the relationship between tree density and type, temperature, and heat-related health risks. "By connecting all of these pieces, 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." Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly.
A major breakthrough in the research was figuring out how to use images taken by "constellations" of PlanetScope satellites, deployed by satellite imaging company Planet, which take high-resolution pictures and circle Earth every 90 minutes. Katz said using satellite images for tree identification has been a "holy grail" in his field for decades, but the images are often difficult to access and not at the scale needed for tree identification. The Cool Trees team, including first author and researcher David Miller, took advantage of the large quantity of PlanetScope images taken over time so they could track the trees' leaves changing in the fall or when they first put out buds in spring, for example.
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