On a hot day in New York City, my only need is: shade.
This is one of the reasons I appreciate plants, especially those with large leaves. But there’s actually more: Trees absorb carbon dioxide and other pollutants, help clean the air, and stop planet-warming emissions. They not only block the sun, creating shade, but pump water vapor through their leaves, which cools the air. Their roots, meanwhile, help rainwater seep into the ground that might otherwise flood the streets.
Plus, trees are literal Make us worry less. People living in urban neighborhoods with more trees There is less pressure.
My point: trees are good.
It’s not exactly a revelation, but it’s a point worth underscoring, as New York, Phoenix and elsewhere — don’t have enough of them. And these treeless city stretches are often home to disproportionately white and low-income residents. Planting more trees in this neighborhood is about more than aesthetics. It can literally help keep people alive.
However, how can a place like NYC bridge these life-threatening gaps in tree planting and tree cover? Litter-laden, concrete-covered blocks aren’t exactly ideal for growing. Then there is climate change, which is raising temperatures and pushing more saline water onto land, thus altering growing conditions.
To understand how big cities think about the role of trees and where to put them, I spoke with Jessica Einhorn, head of the New York City Department of Parks and Recreation’s forestry program. Einhorn, a trained forester, oversees tree conservation and planting in the city. Our conversation has been edited for length and clarity.
Shadow is very important, but it is not distributed equitably
Benji Jones
As cities warm, trees provide an obvious benefit — shade — but can you explain how big that benefit is?
Jessica Einhorn
On a hot summer day, the surface temperature in the shaded area can be anywhere in between 20 to 45 degrees cooler than unshaded areas. It’s wild.
Benji Jones
How do you choose which species to plant?
Jessica Einhorn
We have over 130 different species listed. We tried to diversify our planting palette. When you diversify the urban forest, you are actively planning for the spread of different diseases. If we only had five different trees throughout our city, a pest like the emerald ash borer could come and destroy a high percentage of them.
We consider the site’s land use — whether it’s a commercial or residential strip, industrial land or park area — and whether there are overhead wires. We don’t want a tree to become a wire and cause an outage. In this case, we can plant small species, such as a plum tree or a lilac tree. Small trees tend to be flowering species, but they often don’t have the same longevity as tall trees.
In a heavily trafficked commercial field, we may want to choose a particularly hardy species such as the honey locust. They can take a lot of compacted soil and tolerate a decent amount of drought.
The surrounding environment is another big factor in our consideration. We have significantly changed our approach to planting since Superstorm Sandy, when we saw significant saltwater inundation and a major decline in tree health. Many trees across the city have died – such as the London plane tree, which is not salt tolerant. We are definitely paying attention to plant species that are salt tolerant, such as hawthorn and hackberry, Salt water inundation zone.
Benji Jones
Does the amount of shade the tree provides take into account?
Jessica Einhorn
Our goal is to maximize tree canopy, so we want to plant the largest trees suitable. If we have a large open space along the road to grow, we want to plant our larger canopy trees, such as oak species. Other trees, such as linden trees, have very broad leaves and can provide really dense shade.
Benji Jones
How do you determine where to plant them?
Jessica Einhorn
Right now, we prioritize fields for tree planting Heat Vulnerability Index [HVI]. It is compiled by the city’s health department and is based on several factors, including surface temperature, green space, access to home air conditioning, percentage of low-income residents and percentage of non-Latinox black residents. . We’re focusing on these historically disadvantaged populations to increase tree canopy in areas where, historically, we didn’t have as many trees.
We promise to fully stock the HVI 4 and HVI 5 — Areas with the highest heat risk — by 2027. This means you have a forester walking down the block, looking for any available planting spots and marking them.
Benji Jones
Only a small percentage of the city’s trees are in areas populated mostly by people of color. Will this planting effort help close this gap?
Jessica Einhorn
It will help, but we have a long way to go. Historically, wealthy communities were designed with trees in mind while disadvantaged communities were not. Even if we fully stock historically underserved areas, we will not be able to match canopy coverage in historically underserved areas. Blocks cannot accommodate so many trees because there are other infrastructures that cause collisions.
Heat-loving plants brought to the north
Benji Jones
Are all plants indigenous?
Jessica Einhorn
About half of the 130 plus plants are not from the United States. The landscape and streetscapes of New York City don’t mimic anything native to the area. Many native trees are not hardy enough; They cannot tolerate much of the general environment in such dense urban areas.
You can define locale in several ways: locale to the United States or locale to this particular region? We are introducing trees from warmer climates as our climate trends in that direction, such as crepe myrtles or southern magnolias. Historically, these trees have not been found in NYC, but due to the impact of climate change and the urban heat island effect, we are considering planting them. Some may consider them native, others may not.
Benji Jones
How much do you consider allergies? Have you considered planting less pollinated trees?
Jessica Einhorn
No. Shade and hardiness take precedence over pollen dispersal.
Benji Jones
Why are there so many ginkgo trees in the city?
Jessica Einhorn
This is another tree to add to the “very hardy” list. They can really endure a lot. And they are beautiful; Their leaves shimmer in the wind.
Benji Jones
How are you preparing for a warmer future?
Jessica Einhorn
We are introducing tree species from more southern climates. We’re not going full tropical here, but we’re looking south. We can now plant crape myrtle very successfully here, where 15-20 years ago we would not have considered it.
Then we also have to phase out other tree species that no longer fit here. One of my favorite tree species, the sugar maple, we don’t really plant anymore because the city doesn’t have a suitable climate.
