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.
The Seattle City Council recently passed Council Bill 120534 establishing new tree protection requirements on private property in Seattle. The new regulations went into effect 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.
Read the Code & Supporting Resources
You can read the code online through Municode SMC Chapter 25.11. Occasionally there is a lag in updates to the online code, but you can still view the approved ordinance on the City Clerk website or by clicking on the “Amended by Ordinance No. 126821” link in Seattle Municipal Code 25.11. These new codes apply to actions and projects vested to land use regulations on or after July 30, 2023.
We have published three Director’s Rules (two final and one draft) to provide guidance on the update tree code, which will be finalized in early August:
- DR 7-2023, Designation of Tier 2 Trees
- DR 8-2023, Payment in lieu of tree replacement pursuant to the Tree Protection Code
- Draft DR 10-2023, Administration of the Seattle Department of Construction and Inspections Tree Service Provider Registry
Please continue to check the Director’s Rules webpage for draft and final Director’s Rules. Additional rules are anticipated to guide tree protection areas and tree replacement requirements.
In addition, we are updating the Tip 242 series related to trees to help you navigate the code provisions and application processes:
- Tip 242A, Tree Requirements Associated with Development (updates coming mid-August)
- Tip 242B, Tree Removal on Private Property (updates coming mid-August)
- Tip 242C, Tree Service Provider Registry
- Tip 242D, Tree Public Notice
Please continue to check the Tips webpage for additional updates.
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 Director’s Rule 7-2023, Designation of Tier 2 Trees.
- 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 Director’s Rule 7-2023, Designation of Tier 2 Trees.
- 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 Director’s Rule7-2023, Designation of Tier 2 Trees.
- 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 (developed or undeveloped), 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.
- Removal of Tier 1, Tier 2, Tier 3, or Tier 4 trees is generally prohibited in all zones when no development is proposed either on developed property or undeveloped land. While tree removal is generally prohibited when no development is proposed, the tree protection regulations have several new exemptions and allowances for tree removal. For example, invasive tree species removal and removing a tree infected with pests or pathogens would be allowed. Most of these exemptions and allowances require SDCI review and approval prior to the tree work and will be reviewed via a Tree Removal and Voluntary Restoration Approval Request application. Please also consult Tip 242B, Tree Removal on Private Property (coming in mid-August).
- The tree regulations continue to have limits on tree removal on developed lots when no development is proposed. These limits have been reduced to no more than two Tier 4 treesin a three-year period in Neighborhood Residential, Residential Small Lot, Lowrise, Midrise, Neighborhood Commercial, Commercial, and Seattle Mixed zones and no more than three Tier 3 and Tier 4 trees in a one-year period in all other zones.
- When development is proposed, any tree removals, protection, and replacement trees will be evaluated through the standard permit review process as it is currently done.
- Tier 1 trees generally must be protected and may not be removed unless they are hazardous or require an emergency action.
- Tier 2 trees generally may not be removed unless they are hazardous, require an emergency action, or are permitted to achieve allowed development capacity per SMC 25.11.070 and 25.11.080.
- Tier 3 and 4 trees are allowed to be removed or protected at your option.
Please also consult Tip 242A, Tree Requirements Associated with Development.
Below is a summary table to guide property owners and tree service providers on the tree removal allowances described above:
|Limited Tree Removal Allowed on Private Property
|Tree Removal Allowed
|When no development is proposed
|Hazardous trees (SDCI review required; replacement required for Tier 1, Tier 2, and Tier 3 trees).
|NR, RSL, LR, MR, NC, C, and Seattle Mixed zones
All other zones
|When development is proposed
|NR, RSL, LR, MR, NC, C, and Seattle Mixed Zones
SDCI review is required; replacement is required for Tier 2, and Tier 3 trees, including hazardous trees.
|All other zones
SDCI review is required; replacement is required for Tier 1, Tier 2, and Tier 3 trees, including hazardous trees.
1. Emergency actions allowed according to SMC 25.11.040.
2. Commercial tree work to be completed by a registered Tree Service Provider according to SMC 25.11.100.
3. Tree Public Notice is required according to SMC 25.11.100.
4. Trees not listed in this table are prohibited from being removed unless exempted from regulation by SMC 25.11.020. SDCI review may still be required.
5. Tree work located within an ECA is regulated by SMC 25.09.
Tree Removal Application Process
Generally speaking, our permit processes are not changing, but you will now be able to apply for specific reviews given the new tree removal allowances in SMC 25.11.020 and 25.11.050 (where we currently only have a review available for hazard tree removal). Starting on July 30, you will be able to apply for a Tree Removal and Voluntary Restoration Approval Request application to request review for the following types of tree removal outside of development:
- Hazardous tree removals (Tiers 1-4, with replacement required for Tiers 1-3; see SMC 25.11.040 for more information)
- After-the-fact documentation of emergency tree removal (Tiers 1-3, no replacement required; see SMC 25.11.030 for more information)
- Tree removals due to insect, pest, and/or pathogen infestation (Tiers 1-4, with replacement required for Tiers 1-3)
- Tree removals to comply with ADA or to improve access for elderly or people with disabilities (Tiers 1-4, no replacement required)
- Removal of invasive or nuisance trees (Tiers 1-4, with replacement required for Tiers 1-3)
- Removal of trees to thin overplanting (Tiers 3 and 4, no replacement required)
- Removal of trees causing obvious damage to property (Tiers 3 and 4, replacement required for Tier 3)
- Removal of dead trees (Tiers 1-4, no replacement required)
For assistance with the application process, please consult How to Apply for SDCI Approval for Tree Removal and Vegetation Restoration.
New Site Plan Requirements
The tree protection code now includes requirements for what needs to be included on site plans:
- Tier 1, Tier 2, Tier 3, and Tier 4 trees, including off-site Tier 1, Tier 2, Tier 3, and Tier 4 trees with canopies overhanging and/or roots extending onto the lot, are required to be documented on all site plans within a plan set submitted for a Master Use Permit or building permit.
- Tree protection areas for all Tier 1, Tier 2, and Tier 3 trees that will be retained during development are required to be identified on all site plans.
- Tree protection fencing and signage are required to be shown in the plan set submitted for a Master Use Permit or building permit.
New Tree Replacement Requirements
In all zones, Tier 1, Tier 2, and Tier 3 trees removed in association with development must be replaced by one or more new trees. A list of acceptable replacement trees can be found on this Green Factor Tree List.
If tree removal is approved, replacement trees may be located on- or off-site according to SMC 25.11.090 and SMC 25.11.115. Applicants may choose to make a voluntary payment in lieu of on-site tree replacement. Payment in lieu of replacement planting is calculated pursuant to Director’s Rule 8-2023, Payment in lieu of tree replacement pursuant to the Tree Protection Code. If an applicant chooses voluntary payment in lieu of on-site tree planting, all payments must be made to SDCI before SDCI issues a tree removal approval.
New Street Tree Requirements
Street tree requirements now apply in Neighborhood Residential (NR) zones.
New Development Capacity Calculation for Removal of Tier 2 Trees in Lowrise zones
- The tree protection regulations include the use of a development capacity calculation to determine if Tier 2 trees may be removed on sites undergoing development in Lowrise (LR) zones. Instead of using floor area ratio (FAR), an allowable development area of 85 percent is used. If the 85 percent allowable development area cannot be achieved without extending into the basic tree protection area, Tier 2 trees may be removed. A new Director’s Rule (coming in August) will provide clarity around the basic tree protection area.
- Streamlined Design Review is no longer required when Tier 2 (formerly exceptional) trees are on the site. The new tree regulations include specific modifications to development standards as a Type I decision if an applicant chooses to retain Tier 2 trees that would otherwise be allowed to be removed. Development subject to Design Review will continue to use the available Type II Design Review departures.
Environmentally Critical Areas
- Tree work within an environmentally critical area (ECA) is exempt from most of the regulations of SMC 25.11 (tree code) when a tree and vegetation management plan per SMC 25.09 is required. When this plan is not required, SMC 25.11 applies.
- 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.
Tree Service Providers & Tree Public Notice
- Remember that all commercial tree work (which includes some pruning) must be completed by a registered Tree Service Provider. Please also consult draft Director’s Rule 10-2023, Administration of the Seattle Department of Construction and Inspections Tree Service Provider Registry, and Tip 242C, Tree Service Provider Registry.
- Remember that all tree work (with the exception of emergencies) must be must noticed in accordance with SMC 25.11.100 and posted on-site during the work and online using SDCI’s Tree Public Notice Please also consult Tip 242D, Tree Public Notice.
The best way to contact our staff is via email at firstname.lastname@example.org 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.