John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Mapping 592,130 trees right down to trunk size.
Though New York can sometimes seem like a drab warren of chain-link fence and oily pavement, the city actually has an impressive number of trees. On the streets alone—not counting private properties and parks—there were 592,130 at last reckoning, a leafy explosion you can now peruse in this great visualization of tree species.
Jill Hubley, a Brooklyn web developer whose last project involved mapping local chemical spills, made the chlorophyllous cartography with data from the 2005-2006 Street Tree Census. Zoomed out, it looks kind of like oodles of stained cells under a microscope:
But drilling into the neighborhoods reveals tremendous detail. All 592,130 trees are represented and color-coded, including this rainbow forest outlining Central Park:
Included is each tree's identity, whether it be birch, crabapple, or common hornbeam, as well as trunk thickness for all you plant sizeists. So what's the most tree-jammed borough in this map? Queens snags the crown with more than 40 percent of all street trees, and Brooklyn comes in second with 24 percent. However, Manhattan wins for sheer density, supporting nearly 50 trees for every mile of sidewalk.
Hubley says she's surprised at the appearance of lesser-known species, including Kentucky Coffeetrees, natural sources of fly poison, and Katsura trees, whose "fallen leaves exhale a sweet fragrance evocative of cotton candy," according to one appreciator. Big differences in each borough's makeup also caught her off guard. She emails:
I would've thought the trees throughout the city would be fairly homogeneous in terms of the percentages planted. Instead, Brooklyn has more London Plane trees than any other species (23.6%), Queens has a ton of Norway maples (18.3%), the majority of Manhattan's trees are Honey locusts (23.3%), and Staten Island has a high percentage of Callery pears (24.8%). The Bronx has the most evenly distributed assortment of trees—Honey locust, Norway maple, and London Plane tree are all popular (11-13% each).
Some caveats: This viz shows only a slice of the city's total vegetation. Street timber forms about a quarter of New York's urban canopy, according to the tree census. (Hubley didn't include parks because of a lack of reliable data.) And when the 2015 tree census comes out, it's likely to reflect a significant change in the city's sidewalk-shading greenery.
"The number of street trees increased 19% from 1995 to 2005, and I imagine there has been another huge jump in the last decade due to the MillionTreesNYC initiative," she says.