ISA Certification and Credentials

The ISA Arborist Certification Program is a voluntary effort among professionals in the tree care industry to establish a standard of quality in arboricultural work, to promote and encourage continuing education, and to provide the public with a mechanism for identifying qualified ISA Certified Arborists.

The ISA Certification process builds upon a strong base of knowledge required to obtain each credential, defining a career path in arboriculture through the certification programs. Explore the types of certification available to learn which suits your needs.

The International Society of Arboriculture works hard with its members to keep improving the standards of professional tree care. Certification by the ISA is an important commitment to ethical tree care practices and lifelong learning to build knowledge and skills. The work required to become certified and maintain certification is an indication of professionalism and a desire to maintain high industry standards.

Hire an Arborist

We want to remind everyone to hire an ISA Certified Arborist. Our For Hire ISA Certified Arborist directory will guide you toward our ISA Certified Arborists that are members of the PNW-ISA and specialize in trees specific to Alaska, British Columbia, Idaho, Oregon, and Washington.

How to Become Certified

Certification demonstrates a commitment to continuing professional and technical development, as well as ethical workplace practices, that supports a high level of professionalism in the tree care industry which benefits all certified tree care workers. Visit the main ISA site for more information.

Eligibility Requirements

Be sure you read the appropriate handbook for more detailed information about the requirements for each testing method.

Application Handbooks

Download the application handbook to review full details about the exam and application process. Use the application in the handbook if you would like to apply for your exam by mail or FAX.

Online Applications

Use the links below if you would like to apply for your exam online.

Maintaining Certification

To maintain the certification, a recertification fee must be paid and a minimum of 30 continuing education units (CEUs) must be achieved by the end of the three-year period. Again visit the main ISA website for more information.

ISA Code of Ethics

The ISA Certification Board has implemented an ISA Certified Arborist Code of Ethics policy to serve as a central guide and reference for arborists in support of their day-to-day decision making. It is meant to define our organization's mission, values and principles, linking them with principles of professional conduct and industry standards. The Code of Ethics is an important communication tool with customers. It also helps maintain consistency around the world and create an even playing field for all ISA Certified Arborists.

ISA members will:

  • Strive for continuous self-development by increasing their qualifications and technical proficiency by staying abreast of technological and scientific developments affecting the profession.
  • Not misuse or omit material facts in promoting technical information, products or services if the effect would be to mislead or misrepresent.
  • Hold paramount the safety and health of all people and endeavor to protect property and the environment in the performance of professional responsibilities.
  • Subscribe to fair and honest business practices in dealing with clients, suppliers, employees and other professionals.
  • Support the improvement of professional services and products through encouraging research and development.
  • Observe the standards and promote adherence to the ethics embodied in this Code.

ISA Certified Arborist® Code of Ethics
The ISA Board of Directors have further adopted Codes of Ethics for Certified Arborists, Tree Work Specialists, and Board Certified Master Arborists to support quality tree care and customer service by the industry.

Along with the new Codes, procedures were instituted to investigate ethics charges. Complaint statements are available to ensure anonymity and fairness in pursuing such charges. All certification candidates must sign a Code of Ethics Agreement at the time of the certification examination.

Arborist Credentials

Find a detailed description of ISA credentials and Affiliated Professions associated with the ISA here.

Proctor Information

ISA Certified Arborist Exams

The ISA Certified Arborist exam is a written test consisting of 200 multiple-choice questions. The exams listed in this section are administered by the PNW-ISA. The Certified Arborist exam costs US $150 for members of both the ISA and the PNW-ISA and US $250 for non-members or those who hold membership in only one of the organizations.

ISA Certified Tree Worker Exams

The Certified Tree Worker exam consists of a 50 question multiple-choice written test and a climbing skills test. The Certified Tree Worker exam costs $115 for ISA and PNW-ISA members and $165 for non-members or members of only one organization. Find exam dates and locations at the ISA website.