ISA Certified Arborists In Portland & SW Washington

Serving Families Throughout Portland & the Pacific Northwest

Serving Portland metro, Salem, Yamhill Counties and SW Washington since 1924, General Tree Service has always focused on providing quality services to its customers.  This includes making sure our employees are well-trained and use industry-approved techniques and procedures.

To this end, we encourage our staff to participate in ongoing education in arboriculture.  As a result, we have many ISA Certified Arborists and others who have been certified and/or received training in tree-related areas.  This post focuses on Certified Arborists.

General Tree’s Certified Arborists

Here’s our list of current General Tree employees who have passed the exam and completed all items to become an ISA Certified Arborist.

  • Clint Landon PN-1008A
  • Ray Carter PN-0517A
  • Steve Zetterlund PN-1011A
  • Eric Brockmeyer PN-6776A
  • Greg Doering PN-0676A
  • Jim Sherwood PN-0252A
  • Iris Reimnitz PN-8477A
  • Matt Clark PN-8585A
  • Kyle Fordham PN-0676A
  • Brian Haskins PN-8879A
  • Mike Mills PN-0634A
  • Kevin Murphy PN-0923A
  • Mikel Richards PN-8586A
  • Juan C. Rodarte PN-9029A
  • Ryan Smith PN-8902A
  • Clay Taylor PN-6366A

What is an ISA Certified Arborist?

Offered by the International Society of Arboriculture (ISA), ISA certification is a voluntary program and applicants must pass a written exam.   With a Certified Arborist, you can feel confident you are getting quality tree care that includes practices approved by the tree industry.


ISA Certified Arborists have passed a comprehensive written exam that tests their knowledge in the following areas.

  • Soil management
  • Identification & selection
  • Installation & establishment
  • Safe Work Practices
  • Tree biology
  • Pruning
  • Diagnosis & treatment
  • Urban forestry
  • Tree protection
  • Tree risk management

In addition, they have real-life experience dealing with all kinds of tree-related issues.  It’s the combination of field experience and knowledge that makes them an invaluable source for taking care of your trees, shrubs, and plants.


Candidates must have at least 3 years of full-time experience in arboriculture or a combination of education and practical arboricultural experience.

There is an extensive list of acceptable combinations of experience and/or education that qualifies, and applicants need to show documentation before their applicant is accepted.  For example, 1 year of FT experience is equal to 2,080 hours of work.


Once you pass, certification is valid for 3 years.  You recertify by either taking the exam again or accumulating at least 30 continuing education units (CEUs) over the 3-year period.

The CEUs must be related to the 10 areas covered by the test and applicants must provide documentation of completion.  As you can see, ongoing education is built into the program.  This ensures arborists are always learning and staying current on the latest industry standards and practices.


Clint Landon (president of General Tree Service) is a Board-Certified Master Arborist, the highest level of certification offered by ISA.  In addition to being an ISA Certified Arborist in good standing, he was required to have a total of 8 points from a list of 4 categories (measurable experience, formal education, related credentials or professional experience) to be eligible for the exam.

The exam is a separate (and different) written test that covers 19 areas of knowledge under 3 main topics: science, practice, and management.  Certification is valid for 3 years, upon which you must either retake the test or accumulate at least 60 CEUs related to the 19 areas covered in the test.


As you can see, achieving and retaining an arborist certification requires dedication to the industry.  General Tree is proud of our arborists and their ongoing commitment to providing the best tree care to our customers.

If you have questions about our services or need to schedule an appointment with one of our Certified Arborists, contact General Tree Service.

The post ISA Certified Arborists In Portland & SW Washington appeared first on General Tree Service.

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