Despite its nickname, the Elm City’s most common tree is not the elm, a Urban Resources Initiative representative shared at a Saturday Tree Identification Workshop.

Although Dutch elm disease devastated New Haven’s American elm population decades ago, New Haven now has one of the most progressive tree programs in Connecticut, aiming to restore the city’s tree canopy. Furthering this cause, URI , a nonprofit urban forestry partnership between the Yale School of Forestry & Environmental Studies and New Haven that plants 40 different species of trees throughout the city, hosted a workshop in East Rock Park this Saturday to teach students and residents how to identify local trees.

“New Haven, with URI and the great staff they have, is probably one of our leadership cities in the state,” Connecticut’s State Forester Christopher Martin told the News last week.

Since 2010, URI has helped plant more than 4,000 trees, many by workers at GreenSkills, URI’s tree planting program that trains and employs high schoolers and formerly incarcerated adults. These trees are part of the URI Tree Haven 10k campaign, which aimed to plant 10,000 new trees in New Haven by 2014 to provide more local jobs and increase the tree canopy. Because the goal was not met at the original deadline due primarily to a small number of staff, URI GreenSkills manager Katie Beechem FES ’15 said, the program is still ongoing, with no revised deadline as of yet.

In addition to aesthetic improvement, Beechem said the 32,000 street trees in New Haven improve air quality, produce oxygen, reduce temperature and absorb storm water — initiatives that save the city about $4 million each year. Beechem said that street trees also add social benefits to cities, such as a “calming effect” on traffic. In order for a tree to be planted near the street, it must be resistant to disease and insensitive to the salt applied to icy streets, as well as have strong branches to withstand storms and slow growing roots to prevent sidewalk breakage, according to URI Associate Director Chris Ozyck, who led Saturday’s workshop.

During the workshop, Ozyck gave each group a guide to New Haven trees and introduced the basics of identification. He taught attendees to first identify the leaf type, distinguish how it is attached to the branch and then ask several if-then statements as shown in a “leaf key” at the front of the guide. The book helps identify 90 different species of trees.

The Elm City’s most common street tree is the invasive Norwegian maple, which outcompetes surrounding trees and frequently breaks in high-wind storms, Ozyck said.

“The most resilient forest is a diverse forest,” Beechem said. New Haven’s foliage shows much of this diversity. For example, Asian elms and American-Asian hybrids are resistant to Dutch elm disease, so URI plants plenty of those species around town, Beechem said. She added that, in contrast, American elms must be treated for the disease, and, due to high costs, the city treats only a small population, many of which live on the New Haven Green.

Similarly, the ash tree population is also plummeting due to an invasive species — the Emerald ash borer, a species of beetle. Beechem agreed that it was only a “matter of time” before the ash completely disappeared from New Haven. Because of these vulnerabilities, URI plants many other species to foster a more pest-resistant forest.

Beechem gives much credit to the public for the thriving tree population. Residents are highly involved in the program, according to Beechem, and, after requesting trees be planted in specific spots, residents are then responsible for providing the plants with sufficient water. Trees return the favor by increasing property value and decreasing cooling costs through the shade they produce, according to Beechem.

Before human settlement, New Haven and much of the Northeast was covered by white oak trees, a species still present in Connecticut. The white oak produced wood ideal for timber, which settlers harvested and used for ship construction and trade. According to Ozyck, white oaks were a major contributor to robust economic growth in the surrounding area.

Today, the white oak is honored as Connecticut’s state tree.