Showcase · Data layers · NYC Open Data

Twenty years of street trees

How have New York City’s street trees changed, neighbourhood by neighbourhood, over three censuses? Every live street tree the city counted in 1995, 2005 and 2015, placed by its own position.

Every ten years Parks staff and volunteers have walked every block and recorded every street tree. The censuses counted 482,509 live street trees in 1995, 584,252 in 2005 and 652,173 in 2015: 169,664 more (+35.2%) in twenty years. 174 of 188 neighbourhoods have more, and 14 have fewer. This is measured change: what each census recorded, counted the same way each time.

Three tables, one map

The city publishes each census as its own table, with its own columns and spellings: the 2005 table leaves the neighbourhood blank for about 24,000 trees, the 1995 table placed its trees from addresses years later, and the same species is “maple, norway” in one and “Norway maple” in another. None of them compares the three. Here every live tree is placed by its own latitude and longitude into a 2010 neighbourhood, and the three censuses go on one map with a slider.

The map

Each neighbourhood coloured by its street trees per km² in the census on the slider, or by the change from 1995 to 2015. Press Play to step through the censuses. East New York zooms to its three neighbourhoods, where each dot is a tree in the census on the slider. Hover over a neighbourhood, or tap it on a phone, for its numbers.

The Bronx and Brooklyn gained most

Every borough has more street trees than in 1995. The Bronx went from 41,830 to 78,894 (+89%) and Brooklyn from 106,540 to 167,857 (+58%). Queens, which had the most to start with, gained 17%. 51 neighbourhoods at least doubled; the median change was +44%.

East New York, tree by tree

East New York’s three neighbourhoods (East New York, Cypress Hills and East New York (Pennsylvania Ave)) had 5,370 street trees in 1995, 6,717 in 2005 and 15,402 in 2015, +187%. The largest gain of any neighbourhood was East New York: 2,892 trees to 9,162. On the map’s East New York view each tree is a dot, and the slider shows each census’s own trees.

Norway maples, 1 in 5 to 1 in 20

In 1995 the Norway maple was the city’s most common street tree: 106,909 of them, 22.2%. By 2015 there were 34,189, 5.2%, as old trees came down and other kinds went in. London planetrees are still the most common, at 13.3%, and the mix is wider: honeylocust, Callery pear, pin oak, cherries, lindens and zelkovas each now make up 4% to 10%.

How it was made in Plotlay

1. A map project on the USGS National Map topo base map (public domain), and a data layer.
2. Neighbourhoods: Take all. The neighbourhood file as a layer to pick from, with its licence: 188 areas in one step, keyed by their own code.
3. Link by key the trees in each census as a time axis (1995, 2005, 2015), and the change from 1995 to 2015.
4. Place by position every tree in East New York, shown as dots that follow the slider.
5. Colour by trees per km² in each census, then by the change, diverging round zero.
6. Charts and map pictures in the Analysis workspace, each exported as PNG.
7. Export GeoJSON, TopoJSON for the Power BI Shape Map, CSV with WKT and the linked data.

More about Data layers · Make a data layer of your own

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Python

A narrated Jupyter notebook reads the tables and shapes, recomputes every number on this page, maps the change and plots East New York tree by tree.

Download the notebook (with its outputs) and the data. Both are also in the repository on GitHub.

Read it carefully

• Measured, census by census. Each number is what a census recorded. A tree is a live record: dead trees, stumps, shafts and planting spaces are left out of all three.
• The censuses were run differently. 1995 positions were worked out later from addresses; 30,193 of its trees could not be placed and 15,778 go to the neighbourhood the census named. In 2005, 8,715 trees have neither and count only citywide. A small difference in one neighbourhood can be method rather than trees.
• Neighbourhoods are the 2010 Neighborhood Tabulation Areas, dissolved from the 2010 census tracts. Parks, cemeteries and airports are left out of the map; the trees counted in them count only citywide.
• Street trees only. Park trees and trees on private land are not in the censuses, so this is not canopy cover. The Melbourne canopy showcase looks at shade and how long it will last.

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