Tree Protection in Washington County, OR (2026)

2 county-level rules, plus city-specific rules for 2 cities in Washington County, Oregon.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Washington County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Protected Tree Species

In Significant Habitat areas within the urban growth boundary, only trees on the county's Native Tree List Category A that are 6 inches DBH or larger count as "Regulated Trees" subject to retention rules, and three species (white oak, Willamette Valley ponderosa pine, and madrone) earn extra retention-point value.

Washington County Regulated Native Tree Rule

Significant Restrictions

Washington County Community Development Code §§ 422-9.3(B), 422-9.4

422-9.3 Exceptions to Regulated Tree Definition. The following trees are not Regulated Trees and are not subject to the tree preservation requirements of Section 422-9.5. ... B. Trees (native or non-native) that are not identified in the adopted Washington County Native Tree List as Category A or that are less than 6 inches DBH, unless such trees will be retained to meet the requirements of thi...

Full ordinance details →Official source ↗

Parkway Planting

New development in unincorporated Washington County that fronts a public or private street must plant street trees under Community Development Code Section 407-7, spaced at roughly one tree per 35 feet of road frontage, chosen from the county's approved species list, and installed no more than five feet from the right-of-way.

Washington County Street Tree Planting Standards

Some Restrictions

Washington County Community Development Code § 407-7 (§§ 407-7.1, 407-7.3, 407-7.4)

407-7 Urban Street Tree Standards 407-7.1 The species of street trees to be planted shall be chosen from the approved list of street trees unless approval of another species is given by the Director through a Type I procedure. Trees shall be selected and spaced to provide canopy overlap for shade. Trees shall be installed at an average of one tree per 35 feet of lineal road frontage unless othe...

Full ordinance details →Official source ↗

Tree Protection by City in Washington County

2 cities in Washington County have their own tree protection rules. Each link goes to that city's dedicated page with code citations.

HillsboroPop. 106,447

2 verified rules • Heritage & Protected Trees, Parkway Planting

BeavertonPop. 97,494

2 verified rules • Heritage & Protected Trees, Parkway Planting

All Washington County ordinances

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