Choosing a Qualified Arborist

Hiring an arborist is a decision that you should not take lightly. Tree work performed incorrectly not only poses a risk to the tree itself but also endangers the person performing the work. An unqualified person may not have proper insurance, leaving a liability burden to the customer that could run into thousands of dollars. Put a professional to work for you and your trees!

Hire a tree care company that is properly documented. Some states require registration by tree care companies. Registration is not, however, a guarantee of quality. Some communities also require arborists to be licensed to work within city limits. You should always check with local agencies to see if licenses and/or permits are required.

ISA Credentials

Ask for ISA Certified Arborist credentials. Current membership in professional organizations such the International Society of Arboriculture (ISA) demonstrates a commitment to quality by the arborist as well as a dedication to keeping up-to-date on research related to trees and tree care. ISA Certification indicates the individual has passed ISA's extensive examination on all aspects of tree care and maintenance. ISA maintains a listing of certified arborists. The searchable database allows you to locate commercial tree care companies and consulting arborists who can help provide the best possible care for your trees.

Search for an ISA Certified Arborist


Ask for references and check them. Select a company or individual with a proven track record of good and ethical work practices. Remember, you are hiring a "doctor" for "preventive care" for your trees; make decisions as thoughtfully as you would for your own health care.

Bids & Estimates

Get bids or estimates from more than one tree care firm. Examine the credentials of the firm and the staff who do the work, as well as the written specifications of the submitted bids. Determine which bid has the best combination of cost, scope of work, skill, and professionalism. Your investment in your trees rests in the hands of the tree care company. Make sure the arborist or firm you hire is knowledgeable and reputable.

Take Your Time

Don't rush into a decision because you are promised a discount. Be sure you understand the work to be done and the cost of the services. Don't pay in full before the work is done; reputable arborists will rarely ask for payment up front.

Avoid arborists who recommend excessive pruning. Knowledgeable arborists rarely recommend topping a tree or other drastic pruning practices that might injure trees or make them hazardous. Reputable arborists more commonly recommend various options to address tree conditions and situations. Avoid any firm or individual who advertises tree topping or view clearing or suggests such practices.

Certification & Licensing

Understand arborist certifications and licenses.  In New England, some states have their own certifications or licenses. Certifications, like the ISA Certified Arborist, are voluntary and demonstrate a commitment to quality and a dedication to arboricultural learning, as well as to keeping up to date on the latest research and industry practices. To become certified through a state program, arborists pass an exam, and in some cases, meet particular work experience requirements.

Unlike certifications, licenses are not voluntary, but are required by law in some states. Arborists practicing in states that require a license must have one to be in compliance. Licensed arborists also must pass an examination that demonstrates proficiency in a variety of arboricultural topic areas. It is common in New England for arborists to have more than one certification and/or license.

States with their own certification programs: 

  • Massachusetts
  • New Hampshire

States with licensing requirements:

  • Connecticut
  • Maine
  • Rhode Island