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Hiring a Certified Arborist

What is a Certified Arborist?

A Certified Arborist (CA) is a tree care professional who has studied the art and science of tree care, passed a qualifying exam and acquires continuing education credits. The Certified Arborist program is run by the International Society of Arboriculture.

Certified arborist meets with client in wooded area.

A Certified Arborist is a professional who follows a code of ethics when working with their client to care for the landscape trees.


For tree care practitioners to become ISA Certified Arborists, they must have at least three years of experience or a mix of college education and professional experience. They are tested on many topics that pertain to tree care, such as: 

  • Planting and pruning
  • Diagnosis and treatment
  • Safe work practices
  • Soil management
  • Tree risk management
  • Tree biology and protection


ISA Certified Arborists must follow a code of ethics, which demonstrates a high level of professionalism. With their experience and training, they are equipped to help their clients maintain the health and beauty of their trees. Becoming a Certified Arborist is a voluntary process, which demonstrates an arborist’s passion for the industry, as well as a desire to interact with and fulfill the needs of clients.

An Investment

Trees are living investments that generally increase with age. They provide monetary benefits, such as lowering summer cooling costs by casting shade and reducing winter heating costs by blocking the wind. Therefore, taking the best care of your trees will improve your long-term investment and provide aesthetic benefits as well. 

Blooming tree in landscape with decorative bench and stone pillars.

An aesthetically pleasing landscape is an investment. This landscape has been maintained by a Certified Arborist who uses professional arboricultural standards.

Proper Tree Care

Proper care may also prevent trees from becoming hazardous as they increase in size. Hiring a Certified Arborist who can properly diagnose and correct problems will produce the best results for the longevity of the tree.

While it may cost more money to hire a Certified Arborist, there are significant benefits. Certified Arborists have experience and training to do the job properly. Any person can use a chainsaw to cut down a tree, but a Certified Arborist follows specific techniques and industry standards to safely and properly prune or maintain a tree’s health. 

Important Questions to Ask an Arborist

  1. A large, mature tree in a residential area that has been topped. Text over the background image reads "Do Not Top Trees" with a red prohibition symbol.Are you covered by insurance?
    1. If something were to go wrong, financial liability could fall back on the homeowner if the arborist does not have insurance.  
    2. Ask to see proof of insurance.
  2. Do they adhere to the most up to date ANSI A300 & Z133 professional arboricultural standards? 
    1. Do they consider topping acceptable? If so, you should consider looking for an arborist that follows the standards.
    2. Does the Certified Arborist and their crew members wear the appropriate personal protection equipment and maintain a safe work site? These measures protect them as well as your property. 
  3. Can they provide references?
    1. Ask for a list of clients they have worked with recently and see the kind of work they did. 
    2. A company who is proud of its work should be willing to provide these references.
Arborist in a tree while wearing proper PPE, including a safety hat, safety glasses, and has properly secured the hand and chain saws.

Proper personal protection equipment protects the worker and demonstrates a level of professionalism. This arborist has a safety hat, safety glasses, and has properly secured the hand and chain saws. Climbing spurs are only used during tree removals as they harm living tissue.

Where to Find a Certified Arborist

The International Society of Arboriculture maintains a list of Certified Arborists. You can find a Certified Arborist near you and verify their credentials at

Authors: Karen Cox, WVU Extension Agent – Ohio County; Gregory Dahle, Associate Professor, WVU Davis College of Agriculture, Natural Resources and Design; and Victoria Cruz, Former Student, WVU Davis College of Agriculture, Natural Resources and Design

Last Reviewed: January 2022