Seattle’s tree protection regulations include limits on tree removal and may require tree replacement as part of a development permit. Tier 2 tree removal on sites undergoing development may be allowed if the standards in Seattle’s tree protection standards (Seattle Municipal Code Chapter 25.11) are met. Ordinance No. 127300, effective January 21, 2026, included several updates to SMC Chapter 25.11, specifically related to the tree protection area.
Key changes in tree protection standards include:
- The “basic tree protection area” was deleted from the code. Subsections 25.11.060.A.3 and 4 outline the reductions and modifications that must be used when determining the tree protection area.
- The same tree protection area is used both to determine if Tier 2 trees may be removed in Neighborhood Residential and Lowrise zones and to protect retained trees during construction.
- When calculating whether a Tier 2 tree may be removed to achieve the maximum lot coverage in Neighborhood Residential (NR) zones, required tree protection areas and portions of the lot between any tree protection area and a setback that are less than 10 feet in width are not considered buildable area. This is similar to existing regulations in Lowrise (LR) zones, but the area excluded from the development area calculation is measured at 15 feet from a lot line.
- When there are multiple trees on a NR lot, the analysis to determine if tree removal may be approved is based on the sum of all tree protection areas on the site, not a tree-by-tree analysis. This is similar to existing regulations in LR zones.
Please see SDCI’s Trees & Codes webpage for more information. You may also contact SDCI staff at sdci-trees@seattle.gov or through SDCI’s Submit a Request form.