“Planting trees is political,” Katie Holten told Hyperallergic. And soon, plantings in New York City may spell out messages of resistance, love, or other expressions from the local community. In dialogue with the NYC Parks Department, the Irish-born, New York-based artist designed the New York City Tree Alphabet. Ranging from the elm with its twisting branches for “E,” to the cone-shaped umbrella pine for “U,” each letter of the Latin alphabet is used to highlight one of the city’s native or non-native trees. The selections also represent how the urban forest is transforming due to environmental changes.

“In a sense, the entire A to Z itself is a reflection of climate change,” Holten said. “I wouldn’t have felt compelled to make [the New York City Tree Alphabet] if everything was hunky dory. A large part of the project is the simple fact that it’s a fun, accessible way for people to learn about New York City trees and see how natives, non-natives, and other species new to New York City are all being planted together.”

Holten initially had the idea for a tree alphabet when working on her 2015 book About Trees, published by Broken Dimanche Press. The compendium of tree-related writing, from Ursula K. Le Guin (“The Word for World Is Forest”) to Radiohead (“Fake Plastic Trees”), was translated into visuals of forests through an original tree typeface by Holten.

“As soon as I made the book I realized that a tree alphabet could potentially be used as a planting guide, you could use it to plant messages in the landscape with real trees,” Holten stated. “It was so simple, so obvious, begging to be done.”

Holten developed the New York City-specific alphabet while participating in the Arts and Humanities Residency Program at Fort Totten Park’s Urban Field Station, in Bayside, Queens. In addition to About Trees, Holten had previously engaged in ecology through her 2009 Tree Museum, which involved narrating community stories through the trees along the Grand Concourse in the Bronx.

The New York City Tree Alphabet is available to download as a free typeface. New York might not be regarded as the most tree-friendly city with its concrete-heavy density, still it has an impressive diversity of flora, from the over 300-year-old Alley Pond Giant in Queens (a tuliptree, which gets the “T” in the Tree Alphabet), to the towering dawn redwood, a species thought extinct until its rediscovery in China in the 1940s. It’s now a popular street tree (and the Tree Alphabet “D”). Yet walking through a park or down a street, it’s easy to overlook them as individuals in the blur of green. Holten’s tree illustrations are all bare of leaves, drawing attention to their distinctive silhouettes, such as the broad, shady canopy of the oak and the swayed trunk of the sassafras.

To select these trees, Holten communicated with NYC Parks, with the letters ultimately reflecting the current transformations in the environment. “Parks has three planting palettes: for streets, parks, and forests,” Holten explained. “Their planting lists are shifting — there are trees they’ve planted a lot in the past, but no longer plant for various practical reasons; there are trees new to New York City that they’re planting because of the changing climate.”

For instance, some might wonder why the popular Callery pear was supplanted for “C” by the crabapple. Although it was once considered a great street tree, it’s now recognized as an invasive, brittle-limbed hazard, and is no longer planted by the Parks Department. Holten was toying with “American beech” for “A” since ash trees are not planted after the arrival of the destructive emerald ash borer beetle that wrecked their North American populations.

“But when I visited Ed Toth at the Native Plant Center on Staten Island, I asked him about ‘A’ and the dilemma of using ash and should I use American beech, and he said it should definitely be ash! It’s an important story,” Holten said. “There’s no point in pretending that these things aren’t happening, better to share the story and knowledge and discuss possibilities.” Indeed, Toth and his team are collecting from trees like the ash for their seed banks, so someday these trees can be planted again.

The challenging “X” selection further reflects the long interaction of humans with the area’s nature. While visiting with a Parks Stewardship team, Holten expressed her difficulty in finding a tree for the letter, and proposed using it to represent hybrids instead of a specific tree species. They suggested xanthoxylum, sometimes called “tingle tongue.” It was once employed by the Lenape for toothaches as chewing on its bark, leaves, or twigs creates a numbing effect.

There are already deliberate patterns to tree plantings in the city, whether anticipating climate change, addressing tree diseases, or choosing specimens that will be the perfect fit for a neighborhood block or waterfront park. Now Holten, with NYC Parks, hopes to plant them in messages starting in April. In a living language, the Tree Alphabet will encourage literacy about local nature, the effects of climate change, and conservation. “Meanwhile, everyone’s invited to share messages with us and we’ll select one — or more — to plant,” Holten said. “I’m excited to see people’s love letters, as I call them. Of course, the first word I wanted to plant was ‘Resist.’”

Katie Holten’s New York City Tree Alphabet is available online.