Shoreline, WA Tree Protection: Protected Tree Species (2026)

Shoreline's Development Code creates layered categories of protected trees. A 'significant tree' is any healthy tree six inches or greater in diameter at breast height that does not qualify for a complete clearing exemption under SMC § 20.50.310(A), defined at SMC § 20.20.048. A 'landmark tree' under the same definitions section is any healthy tree over 24 inches DBH that merits long-term protection for its size, shape, age, location, aesthetic quality, or cultural, historic or ecological importance, or that is a regional erratic; long-term protection comes through the City's landmark tree designation program.

SMC § 20.50.350(F) makes the actual protection rule operative: once the City has designated a tree as a landmark tree because it is 30 inches or larger in diameter, or is otherwise impressive or unusual in species, size, shape, age or historical significance, or forms an outstanding row or group, that tree shall not be removed unless the applicant meets the exception criteria in SMC § 20.50.350(B), the same narrow standard used to reduce significant-tree retention percentages generally. The Director of Planning and Community Development sets the criteria and procedures for designating a tree as a landmark tree in the first place.

Separately, SMC § 20.20.040 defines a 'protected tree/protected vegetation' as any tree or understory area shown on an approved tree protection and replacement plan, or otherwise permanently protected by easement, tract, or covenant restriction, whether inside or outside a native growth protection area or critical area buffer.