How do you become an arborist in the United States?

This page reports what the official source says. It is not legal advice: ask the office named here.

US government sources describe entry-level tree work as open without formal education. The Bureau of Labor Statistics (BLS) does not give tree trimmers and pruners a page of their own. It covers them inside the grounds maintenance workers handbook entry, which says entry-level grounds maintenance jobs typically have no formal education requirements, that employers may prefer a high school diploma or equivalent, and that studying arboriculture is helpful. The wider guide to the country is starting in the United States.

What BLS says

Training. Grounds maintenance workers typically need one month or less of on-the-job training, and large institutional employers may add instruction in arboriculture or tree climbing.
Licensing. Most states require licensing for workers who apply pesticides, usually by passing a test on the use and disposal of pesticides. Fertilizer licensing varies by state.
Certification. Professional certification is not required, according to the handbook, though it shows competency and reliability.
Experience. The handbook lists none as required, and says several years of related experience can lead to a crew leader or supervisor role.

The BLS entry is the grounds maintenance workers page of the Occupational Outlook Handbook.

What O*NET says about tree trimmers and pruners

The O*NET OnLine profile for Tree Trimmers and Pruners (37-3013.00), updated 2026, places the job in Job Zone 1 to 2, very little to some preparation needed. That zone usually requires a high school diploma or GED, though some occupations may not, with on-the-job training from a few days to one year. In the profile's survey of what education a new hire needs, 57 percent of respondents said less than a high school diploma, 37 percent said a high school diploma or equivalent, and 4 percent said some college without a degree. Reported job titles include arborist, climber, tree climber and plant health care technician.

ISA certification is voluntary and experience-based

The ISA Certified Arborist program guide sets a minimum of three years of full-time experience in arboriculture, or a mix of education and experience, before the exam. ISA calls certification a voluntary program. The full timing is on how long it takes to become a certified arborist.

Registered apprenticeship

The Tree Care Industry Association's apprenticeship program page is written for companies. It says a registered apprenticeship means registering with the US Department of Labor, following the national guideline standards, setting up support through a senior skilled worker, three years of apprenticeship (5,400 to 6,000 hours), and 440 hours of related instruction at a local community college or through TCIA's own apprenticeship training program. The page offers a second option without registration: online Tree Care Academy courses that use the same content.