Tree Protection in Thurston County, WA (2026)
2 rules for unincorporated Thurston County, Washington.
Verified from official government sources
Heritage & Protected Trees
Thurston County requires 70% retention of heritage trees (40+ inch DBH or culturally significant) on forest-practice development sites under TCC 17.27.400.
Thurston County Heritage Tree Retention
Some RestrictionsThurston County Code §§ 17.27.200, 17.27.400(A)(5)
"Heritage trees" means any tree over forty inches DBH or those which are historically or culturally significant at any size and are identified in a list managed by recognized community groups. ... Heritage Trees. At a minimum, seventy percent of heritage trees on site shall be retained. All retained heritage trees shall be shown to be windfirm.
Parkway Planting
Within the Olympia Urban Growth Area, Thurston County requires street trees as part of frontage improvements on qualifying development under Code Section 23.36.060(G)(3), with species and spacing approved by the county. Section 23.36.080 forces applicants to fold a full street tree planting plan, covering species, spacing, installation, and a three-year maintenance cost estimate, into the project's soil and vegetation protection plan.
Thurston County Olympia UGA Street Tree Rule
Some RestrictionsThurston County Code § 23.36.060(G)(3), § 23.36.080(A)(1)(d)
2.Tree Distribution. Trees in Soil and Vegetation Protection Areas shall be comprised of at least sixty percent evergreen species, unless site conditions are not suitable as determined by the Urban Forester.3.Street Trees. Street trees shall be required as part of frontage improvements pursuant to the Olympia UGA Zoning Ordinance. The species and spacing of required trees shall be approved by t...
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