Hire a Certified Arborist

According to Oregon City's code, a Certified Arborist is "a professional tree service provider whose certification is regulated and current and maintained with the International Society of Arboriculture (ISA). To use the term 'Certified Arborist,' an individual must have three years of experience and have passed an ISA certification exam that tests a variety of tree care knowledge." (OCMC 17.04.082)

Certified Arborists are trained in the science and care of trees and they can recommend ways to improve the health and longevity of trees. However, in some cases they may have to recommend removal.

A Certified Arborist can:

  • Advise you on choosing appropriate street tree species to replant in your planting strip or on your property, or recommend larger-caliper street trees for planting in new developments (OCMC 12.08.015).
  • Determine whether a public tree, street tree, or NROD tree is dead/diseased (OCMC 17.04.1360), hazardous (OCMC 17.04.1363), or an imminent hazard (OCMC 17.04.1370) and should therefore be removed.
  • Demonstrate compliance with a tree removal mitigation plan in a new development (OCMC 17.41.060).
  • Recommend the appropriate tract size for a preserved grove of trees in a new development (OCMC 17.41.080).
  • Recommend a tree protection zone during new construction and supervise any construction activity within that zone (OCMC 17.41.130).
  • Determine if a tree in the Natural Resources Overlay District should be removed, and how to best accomplish the removal in a manner that is safe to people, property, and the community (OCMC 17.49.100.A).

Certified Arborists are credentialed through the ISA and often have the skills and equipment to safely and efficiently remove trees, as well as evaluate them.

When & Why You Need a Certified Arborist Report

A Certified Arborist Report is only needed under certain circumstances. You do not need one if your sidewalk is buckled due to tree root growth - creating a sidewalk mobility hazard - or if the tree is obviously dead or has already fallen over. We request that you include photos of circumstances like these with your tree removal and replacement application.

A Certified Arborist Report is, however, required under the following circumstances:

  • To prove that a public tree, street tree, or NROD tree is dead, diseased, hazardous, or an imminent hazard and thus subject to removal and 1-for-1 replacement.
  • To gain approval for topping a street tree in the course of tree maintenance (OCMC 12.08.025).
  • When demonstrating compliance with a tree removal mitigation plan in a new development (OCMC 17.41.060).
  • When recommending the appropriate tract size for a preserved grove of trees in a new development (OCMC 17.41.080).
  • When recommending a tree protection zone during new construction and supervising any construction activity within that zone (OCMC 17.41.130).

How to Find & Hire a Certified Arborist

When seeking a Certified Arborist, Oregon City requires that you hire a reputable arborist or company with current ISA certification. While Oregon City can't recommend specific arborists or companies, we can link you to the ISA's Certified Arborist directory. All contractors working in Oregon City must also have a valid business license with either the City or Metro.