New Tree Regulations Coming Soon!

The Seattle City Council recently passed Council Bill 120534 establishing new tree protection requirements on private property in Seattle. The new regulations will become effective on July 30, 2023. It is important for property owners, tenants, developers, and tree service providers to understand the new regulations to know when a tree is protected and when a tree may be removed. We are currently developing public information to help explain the new regulations. Please watch for updates on our Trees & Codes website, including links to any new or revised Tips and Director’s Rules.

Why This Matters 

The City of Seattle is committed to protecting our urban tree canopy. Canopy cover is one important measure of the health of the urban forest. Urban trees provide numerous ecological, economic, and social benefits, including wildlife habitat, neighborhood livability, and improved public health outcomes.

Read the Code

You can read the approved ordinance on the City Clerk website or by clicking on the amended ordinance 126821 linked in Municode, our online code. These new codes apply to actions and projects vested to land use regulations on or after July 30, 2023.

We have published two draft Director’s Rules to provide guidance on the update tree code:

• DDR 7-2023, Designation of Tier 2 Trees (public notice)
• DDR 8-2023, Payment in lieu of tree replacement pursuant to the Tree Protection Code (public notice)

New Terminology – Tree Tiers

Trees in Seattle are now categorized into 4 different tier groups – Tier 1, Tier 2, Tier 3, and Tier 4. These new tree tiers replace the exceptional and non-exceptional categories of the current code. Each tier has different regulations that change depending on whether you are proposing development. Trees are measured using the diameter at standard height (DSH), an industry standard for measuring tree size.

• Tier 1 – Includes trees designated as heritage trees. You can learn more about heritage trees by visiting the City’s heritage tree program
• Tier 2 – Includes trees 24 inches DSH or greater, tree groves, and specific tree species as provided by a Director’s Rule (coming soon).
• Tier 3 – Includes trees 12 inches DSH or greater but less than 24 inches DSH that are not considered Tier 1 or 2 trees as provided by a Director’s Rule (coming soon).
• Tier 4 – Includes trees 6 inches DSH but less than 12 inches DSH that are not considered Tier 1 or 2 trees as provided by a Director’s Rule (coming soon).
• Other trees – Trees under 6 inches DSH are not regulated by SMC 25.11

New Tree Protection Regulations

Tree protection requirements vary based on the tree tier, zone, lot condition, and whether development is proposed. In most cases, removal of a tree from any tree tier is prohibited on undeveloped, or vacant lots. Exceptions are made for hazardous trees, which may be removed with approval by SDCI. Trees less than 6 inches DSH are not regulated by SMC 25.11. Below is a table to guide property owners and tree service providers on tree removal allowances. Remember that all commercial tree work (which includes some pruning) must be completed by a registered Tree Service Provider and that public notice of the tree work must be posted on site during the work and online using SDCI’s Tree Public Notice portal.

Tree work within an Environmentally Critical Area (ECA) is exempt from most of the regulations of SMC 25.11 (tree code); however, the regulations found in SMC 25.09 do apply. The tree work within the ECA must still be completed by a registered Tree Service Provider and comply with the notice requirements found in SMC 25.11.100.

Contact Us

The best way to contact our staff is via email at sdci-trees@seattle.gov or through SDCI’s Submit a Request form. To help route your request, indicate that you need help with “Permits, codes, zones, plans,” then select “Land Use” as the type of help you need, and then select “Trees” in the description field. If necessary, we can set up a virtual meeting to discuss potential or actual projects. As we work to understand the new regulations and create public outreach materials, we might be slower to respond than is typical.