Every Neighborhood Leafy (Part One)

Guest Contributor: Emily Nobel Maxwell, Founder and Principal, Nobel Cause Consulting, Senior Advisor, Urban Forestry, City Parks Foundation

Part One of a two-part post. Article adapted courtesy of Vital City.

In Fall 2023, two important laws related to the urban forest went into effect in New York City. Local Law 148 and Local Law 135 together require a citywide urban forest plan across public and private property, ongoing monitoring of the state of the canopy, as well as integrating tree planting and management into the City’s sustainability planning. These laws set the stage for NYC to expand the urban forest and its benefits equitably and to help set a global example for good urban forest planning and investments. The article below, originally published in Vital City, was written prior to passage of these laws, and provides context for their passage and robust background on the urban forest in NYC.

New York is usually represented by images of concrete, steel, traffic and skyscrapers. But green space, especially the tree canopy provided by the urban forest all around us, is as fundamental to healthy, comfortable city living as any man-made infrastructure. Policymakers and residents need to treat trees accordingly, putting a priority on wise, long-term investments that close a massive canopy gap that continues to divide neighborhoods along race and class lines. There are hopeful signs that the city government is already moving in this direction, but we need to do much more, and faster.

Why do trees matter? 

Research is clear that they have tangible effects on our individual and collective well-being. They store and sequester carbon — an absolutely crucial quality in an era of climate change. They filter stormwater. They improve air quality. They provide homes for birds, squirrels, bats and other creatures that keep the city’s ecosystem lively and healthy. 

Growing evidence suggests their presence correlates with improving the quality of our lives, including reduced dementia, improved academic performance, better moods and sleep and diminished stress.

Perhaps most importantly, in an era of intensifying heat, they cool the surfaces and air around them. Research shows that shaded surfaces can be up to 45 degrees Fahrenheit cooler than those that are unshaded. A recent analysis by New York City’s Department of Health and Mental Hygiene shows a 2 degrees Fahrenheit air temperature difference between blocks that are heavily vegetated versus those that are not. A change of a couple of degrees may seem minor, but it’s not — because heat stress takes lives.

Extreme heat and flooding are already upending the comfort and safety of New Yorkers. Heat contributes to the deaths of an estimated 370 New Yorkers each year. The heat-related death rate of Black New Yorkers is twice that of white New Yorkers.

Without rapid and aggressive action, all this is going to get worse. The New York City Panel on Climate Change, the independent city advisory body that synthesizes scientific information on climate change to inform government policy, projects five to seven times the number of heat waves and 1.5 times the extreme precipitation events later this century.

New York City needs to treat trees, and their verdant canopy cover, as a necessity and not an amenity in all neighborhoods. This means both taking care of the ones we have and planting many more — using a pragmatic and well-funded plan that cuts across city agencies and serves have- and have-not neighborhoods alike. 

The state of the canopy

What I refer to as the urban forest is all of the trees in the city, along with their tree beds and soil and all parts of their interconnected system. It ranges from single trees planted on sidewalks to landscaped groves in our parks to densely contiguous forested natural areas. Urban forests are highly managed systems that, to thrive, require significant human attention, including professional arborists, volunteer stewards, climbers and pruners, home gardeners and more.

In the five boroughs, we have more than 7 million trees spanning just over 300 square miles of public and private land, which works out to about 23,000 per square mile of land. That makes our tree density greater than Philadelphia’s (134 square miles and about 2.9 million trees), about 21,500 trees per square mile; and Los Angeles’ (470 square miles and about 10 million trees), about 21,000 per square mile; but far less than Dallas’ (345 square miles and close to 15 million trees), about 43,500 per square mile.

But New York’s relative standing is only one way to gauge our success or lack thereof. Another way to put it: As of 2017, trees covered 22% of the five boroughs, up from 20% in 2010. In this way, New York was bucking the trend — many cities in the U.S. were losing tree canopy over a similar time period.

We know all this because tree canopy is mapped with 3D data collected using a high-tech tool called lidar, a remote sensing method that uses the same principles as radar, but using light from a laser. This data is available from 2010 and 2017 for New York, hence the timeframes discussed here.

Now the bad news: Canopy coverage is glaringly disparate across New York due to both historic and present factors.

Unsurprisingly, Staten Island is the leafiest borough, with about 31% canopy cover. Brooklyn, the most populous borough, is the most sparsely covered, at less than 18%. When we look at neighborhoods, that range is much wider, from under 10% in Hunts Point, East Williamsburg, Sunset Park and Midtown South to over 50% in Riverdale.

Airports and parks and cemeteries provide even further extremes. Perhaps all too predictably, lower-income communities and communities of color tend to have less coverage, which is a big part of what makes them more vulnerable to heat. And systemic racism, including the legacy of historic redlining and current disparity in access to cooling, safe housing and health care resources, deepens these divides.

We should all viscerally understand how it feels to be in low-canopy neighborhoods with little respite from the blazing sun and radiating heat on those dog days of summer. It’s why we cross to the shady side of the street every chance we get. Every year we allow these disparities to persist, we consign swaths of the city to a bleaker future.

A significant piece of the problem is that the city’s urban forest isn’t managed, or regulated, in a coordinated fashion.

Over half of our tree canopy, 53.5%, is overseen by the hardworking yet chronically underfunded Department of Parks and Recreation, whose advocates have been fighting tirelessly for years to try to secure a scant 1% of the City budget to care for about 14% of the city’s land (plus having jurisdiction over street trees!).

Urban forests are highly managed systems that, to thrive, require significant human attention, including professional arborists, volunteer stewards, climbers and pruners, home gardeners and more.

To break that down further, the Parks Department oversees the more than 28% of the city’s total canopy that’s on parkland, plus the 25% of total citywide canopy that spans our streets and sidewalks. This is the best and most consistently managed section of the urban forest. About 3% of the canopy is on other city-owned property. Nearly 8% of the canopy is on state and federal lands. And a whopping 35% is on private property, wholly unprotected.

To be continued in Part Two…