Ashon Leftenant climbed trees as a kid but never dreamed he could make a living at it. Now Leftenant, 27, is training to become an entry-level “tree climber” through the Bronx Environmental Stewardship Training program (BEST), where is learning to tie complicated knots so he won’t fall from the tree when he prunes them with a chainsaw.

Since its inception in 2001, the program, run by Sustainable South Bronx, a local nonprofit group, has trained dozens of New Yorkers in ecological restoration and helped them find outdoor environmental jobs doing tree work and landscaping. Its three-month spring session recently kicked off with a diverse group of trainees from the Bronx, Manhattan and Brooklyn who are learning what it takes to work in the field.

“The key word is passion,” said alumnus Lonnell Richardson, 43, who was hired to work full-time on Bronx River Alliance’s ecological restoration and conservation team, which helps keep the river clean. Richardson, an Army vet, participated in BEST last year. He is currently waging a war against the Japanese knotweed, a bamboo-like plant that grows alongside the Bronx River.

It may sound simple, but environmental work requires extensive safety training, which comes mandatory at BEST. Graduates of the program receive certifications in areas like pesticide application, first aid and CPR. They can also take electives in tree work that can help them score lucrative jobs.

Ivan Ferrer couldn’t find a steady job in New York with his communications degree from the University of Puerto Rico. He took odd jobs at a courier service and an after-school program for two years, while struggling to help his aunt with rent. After the program, however, he became a tree climber at the Central Park Conservancy, and is now doing private tree work in Connecticut.

The free training is offered to a maximum of 10 trainees per session, who receive quality boots through a partnership with Timberland. Other perks include a Carhartt uniform, three 30-day MetroCards, a $600 stipend upon graduation and, perhaps most notably, placement in a job. “Their résumé goes far and wide,” said Annette Williams, project coordinator for SSB who has helped place trainees at the New York City Department of Parks and Recreation, Central Park Conservancy and the city’s three botanical gardens. Bronx River Alliance, another community partner, used to rely on AmeriCorps workers; now, most of its staff comes through the BEST program.

The program started in 2001 as a way to address two problems in its South Bronx backyard: pollution and unemployment. “We wanted to use our own community as a classroom for skills that will support not only what we’re doing here, but also can be transferable to well paying jobs outside the community,” said Majora Carter, executive director of SSB. Community District 2 in the South Bronx, where the SSB offices are located, has the highest unemployment rate in the Bronx and second highest in all five boroughs, according to the New York State Department of Labor.

BEST students spend the first four days of the week out in the field, and Fridays doing class work at SSB’s loft offices in Hunts Point, which overlook a concentration of factories emitting shimmery waves of gas. This Friday, they will go shopping for uniforms together after they wrap up their 10-hour safety course. Later, they will learn about issues of environmental justice, like the connection between the neighborhood’s dozens of waste transfer stations and high asthma rate.

SSB isn’t the only group training New Yorkers to become environmental workers. The National Institute of Environmental Health Science has a Minority Worker Training Program (MWTP) designed to bring more minorities in the construction and environmental remediation industries. But MWTP focuses on training for environmental technicians who do lead abatement and mold remediation says Greg Smith, program manager in the Bronx. “Where we meet is with environmental justice. We show how the problems impact neighbors, and what can be done.”

BEST still faces some challenges. The group accepted only eight trainees this year, and two of them opted out because they couldn’t afford not to work for three months. “It’s good if you have a family member to live with,” said Michael Rosario, 34, who gave up work as an elevator repair man to invest his spring in BEST. To expand its pool of applicants, SSB has applied to be on the New York State Workforce Eligibility Training Provider List, which helps people receiving public assistance find jobs.

The program will also get some public attention this week, as BEST teams up with the Bronx River Alliance to prepare for the “Amazing Bronx River Flotilla,” a three-mile canoe ride down the river. “I want [the trainees] to take ownership,” said Williams. “When they hear people talking about how beautiful the river is, they can be proud of their work.”

—J. Edward Mendez