A Look at Tree Growth in New York as City Pines for Cooler Streets

A tree grows in Brooklyn — several, in fact, but just how fast depends on what species it is and where exactly it’s located.

A study published Thursday led by researchers at Columbia University’s Barnard College dug into the speed of street tree growth over a decade-long period and found the fastest growth, borough-wise, in Staten Island, Queens and in The Bronx.

But some of the fastest sprouting neighborhoods included Greenpoint and Flatbush in Brooklyn. In a bit of good news, many of the neighborhoods where trees grew at the quickest speeds, including Hunts Point and East Harlem, have residents that are most at risk of harm during extreme heat waves due to a confluence of social and environmental characteristics.

The trees that showed slowest rates of growth were in mid- and southern Manhattan and southern Brooklyn.

“Species is really the most important driver [of growth], regardless of the size of the tree and what’s happening around it,” said Elizabeth Cook, an environmental science professor at Barnard College and an urban ecosystem scientist.

Silver lindens grew the fastest, at a rate of about half an inch each year, followed by the Japanese zelkova . The Norway maple and London planetree — the most abundant tree species in the city — were the slowest growers, according to the study.

In compiling the study, the team considered factors like the tree species, how tall buildings were around the tree, the width of the street and whether tree roots had damage.

The findings could help the city Parks Department decide where to plant trees and which kinds. A Parks spokesperson said the department is reviewing the study’s findings.

“This kind of research can inform efforts to make the tree canopy more equitable, and to grow healthier communities,” said Emily Nobel Maxwell, founder and principal of environmental firm Nobel Cause Consulting.

The researchers calculated the tree growth by looking at the diameter of the tree trunk from 2005 to 2015, as documented in the tree census, which consists of tree-level data compiled by Parks staff and volunteers. They examined over 126,000 trees across 59 species. The next tree census will take place in 2025.

Hot Neighborhoods

Another finding: Trees neighborhoods with high rates of “social vulnerability” tended to grow at faster rates. Those neighborhoods, which have higher rates of poverty and larger shares of nonwhite residents, are also those that have historically had less green space and fewer trees.

But those same neighborhoods have room for more trees — and new, younger trees tend to grow faster than older ones, Cook noted.

And lack of trees is a common denominator among the city’s neighborhoods most at risk of death from heat — which contributes to the premature deaths of about 350 New Yorkers each year , with Black residents dying at twice the rate of whites.

“Those are the areas where we would want more,” Cook said. “There are places that are certainly lacking in trees and could use more to help with the cooling and other benefits.”

Planting more trees is just one way to cool those neighborhoods and keep residents safe. (Access to air conditioners, expanded cool spaces and energy bill assistance are also crucial.)

Trees offer shade and carry water from the soil into the air, resulting in a cooling effect. This is particularly important in cities, which tend to be much hotter than rural or suburban areas because of tall buildings that limit air circulation, abundant asphalt and pavement, and heat-generating activities in close proximity to one another.

Mayor Eric Adams’ administration’s 2023 sustainability plan committed to getting the city to 30% of tree canopy cover, about 8% more than the current rate. The City Council last fall codified that goal into law , requiring the parks agency to come up with a plan and report on progress toward the goal.

Parks planted over 17,600 trees in Fiscal Year 2024, which ended in June, with about 17% of those located on streets, parks and forests in neighborhoods that are the most vulnerable to the heat, according to a spokesperson.

Some of those places with new saplings might lack a lush canopy now, but Cook said her data indicated improvement in the future.

“There are a lot of young trees that are relatively small, and they have potential to get bigger in the future, of course, but trees grow very slowly so it takes longer,” Cook said. “There’s hope for all of them, just some of them will get bigger more quickly.”

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