New York (CNN) -- Fabian Vazquez is a teenager who spends hours on end climbing trees in New York City concrete jungle.
He's training to become an arborist, a person who focuses on the health and safety of individual plants and trees.
"I heard about climbing trees and stuff and I was like 'Oh wow that's amazing.' You know I always liked working outdoors."
Fabian is taking part in the Million Trees NYC Training Program, to increase the city's urban forest, which the organization's Web site calls its "most valuable environmental asset."
Explaining the mission, the Web site says: "Trees help clean our air, and reduce the pollutants that trigger asthma attacks and exacerbate other respiratory diseases. They cool our streets, sidewalks, and homes on hot summer days."
For Vazquez, the city says it "provides paid on-the-job forestry, ecological restoration and horticulture training to unemployed young adults not enrolled in school or on a career path."
More than 30 trainees from around New York City are taking part in this seven-month program.
At first Vazquez, from New York's Bronx borough, didn't think he could take the heights.
He said: "I was afraid of heights the first day. I was frightened, I was really scared, but as time goes by you get used to it, it comes like second nature."
While fear of heights is a major challenge for the trainees, so is inclement weather.
"Our program starts up in the fall and runs throughout the winter and it's outdoors primarily. So just getting accustomed to being outdoors despite any inclement weather day in day out is probably one of the biggest challenges," said program director Brian Aucoin.
But Vazquez doesn't mind the outdoors. "I'm not the kind of person who likes to be inside an office and all."
Nonetheless, climbing is extremely dangerous.
"Any slip you can fall so you always have to be careful where you put your foot. You always have to be concentrating on what you're doing, you can't be thinking about the stuff outside work," Vazquez said.
The program director is a big advocate for these young arborists and all the challenges they overcome. "They're getting tangible, employable skills and certifications as well as on the job experience, Aucoin says, "all of which makes them more marketable."
This program doesn't just help Vazquez learn a valuable skill. It also benefits the city which manages nearly 30,000 acres of parkland. 12,000 of those acres are undeveloped and naturalized.
"These trees have not been pruned for 20 years. We have important work being done in our park" noted Commissioner Adrian Benepe of NYC Parks and Recreation.
It's dangerous to have people walking in parks with overgrown trees. "You don't want to be walking in a park and a branch falls on you," said Vazquez.
And with the Million Trees project, the City needs a skilled workforce
Even in an age where technology is taking over from manual labor, there is no substitute for arborists. Through the Million Trees Project, aspiring arborists learn how to climb and trim trees and learn life skills along the way.
"I would say probably 40 percent of the trees we work for in the urban environment aren't accessible with machines so this art and this craft is definitely needed" said instructor Mark Chisholm.
With the help of the program, a green career is that much closer for people like Vazquez.
He is also learning more about trees and nature that he thought he would. "I have a better consideration for trees...I see what they do for us, they give us oxygen."