Hillsboro, OR Tree Protection: Heritage & Protected Trees (2026)
Key Facts
- Douglas fir threshold
- Specimen at 24+ inches diameter
- Cedar/hemlock/fir/pine threshold
- Specimen at 12+ inches diameter
- Oak/maple/alder threshold
- Specimen at 12+ inches diameter
- Removal criteria
- Hazard, disease, or no alternative
- Governing code
- CDC § 12.50.230.D
Summary
Hillsboro's code doesn't use the term 'heritage tree': it protects large 'specimen' trees by species and diameter, like Douglas firs over 24 inches or oaks and maples over 12 inches, from removal during development review.
D.Standards for Specimen Tree Preservation. In addition to the standards in subsection C above, the standards in subsection D apply to the Specimen Trees described in Table 12.50.230-1. ... 1.No specimen tree shall be removed or damaged during development construction unless 1 or more of the following criteria are met:a.A Certified Arborist determines that the tree: ... iii.Was diseased, weakened, or dying before construction began and no practicable means is available to preserve it.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 1 | Community Development Code: Supplement 1).
Full Breakdown
CDC § 12.50.230.D layers extra protection onto species listed in Table 12.50.230-1: a single Douglas fir over 24 inches in diameter, a grand fir, ponderosa pine, western hemlock or western red cedar over 12 inches, a red alder, big-leaf maple or Oregon white oak over 12 inches, or any other qualifying conifer or deciduous tree above 20 inches (measured 4.5 feet above native grade). During a Type II or III development application, a specimen tree can only be removed if a Certified Arborist finds it a hazard, dangerous, or already dying with no practicable way to save it, or if a Registered Engineer certifies there's no practicable alternative for required construction, grading or building placement.
Violations & Fines
Removing or damaging a specimen tree outside the narrow hazard, disease or no-alternative criteria in CDC § 12.50.230.D.1 during a development project is a Code violation, enforceable the same as any other tree-preservation breach.
Frequently Asked Questions
Does Hillsboro have a heritage or landmark tree program?
What diameter makes a tree a protected specimen in Hillsboro?
Sources & Official References
Other rules in Hillsboro
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Heritage & Protected Trees in Nearby Cities
How other cities in Washington County handle heritage & protected trees.