Navigating Seattle's Tree Work Permits & Code Requirements

(Updated as of September 2023)

Blooma Tree Experts has put together this guide to help you understand the Seattle tree code & tree permit process. 

This reference document is designed to provide homeowners with an in-depth understanding of City of Seattle's tree code, which changed meaningfully in July 2023. 

Our aim is to empower you with comprehensive information, enabling you to navigate the regulations effectively. As a client of Blooma Tree Experts, we manage permit compliance for you, ensuring a hassle-free experience. 

There is relevant information below about tree permits and public notices as it relates to tree pruning and tree removals on private properties in the City of Seattle. Let's delve into the intricacies of Seattle's tree code!

Table of Contents:

1. What Does this Guide Cover?
2. What is a Registered Tree Service Provider?
3. What Work Requires a Registered Tree Service Provider?
4. Tree Removal Tiers & Allowances
5. Permitted Removals of Tier 1, 2, or 3 Trees
6. Public Notice Posting Requirements
7. Where to Read More

1. What Does this Guide Cover?

This guide is meant to be a quick reference for homeowners to navigate the City of Seattle's tree code effectively. This is specific to the City of Seattle (each suburb has its own tree code).

While our aim is to simplify the code, it's essential to understand that this document doesn't encompass every situation, exception or nuance.

Importantly, it does not address new development-related tree code; it instead focuses solely on regulations applicable to already-developed residential properties regulated by the Seattle Department of Construction & Inspections (SDCI). 

It's also vital to distinguish this from the code governing street trees or right-of-way trees, which are regulated by Seattle Department of Transportation (SDOT). We are also licensed to work on street trees, but this guide doesn't cover street tree management or permits.

Note: If your property has an Environmentally Critical Area (ECA) mapped onto it – which is typically the case for properties near shorelines, rivers, or on steep slopes – you'll be subject to a more rigorous set of tree code rules. For your convenience, Blooma Tree Experts can assist in assessing your ECA status, or you can use this link to check for yourself. If your property falls within an ECA, we will collaborate closely with you to ensure that your tree work complies with ECA code.

2. What is a Registered Tree Service Provider?

Certain tree work on private property in the City of Seattle mandates hiring a Registered Tree Service Provider. 

This designation signifies professionals with the requisite qualifications to handle tree-related tasks as determined by the city – most importantly, having an ISA-Certified Arborist on staff, and having a minimum $1 million liability insurance policy. 

Blooma Tree Experts is licensed with Seattle Dept. of Construction & Inspections (SDCI) under license #LIC-TSP-18504, which underscores our commitment to excellence in tree care. 

3. What work requires a Registered Tree Service Provider?

SDCI requires hiring a Registered TSP to do the following types of work (unless the homeowner is self-performing):

• Pruning of any live branches that are greater than 4" in diameter or that constitute more than 25% of the canopy (also referred to as “Reportable Work”)
• Any emergency work or work on hazard trees
• Removal of any tree larger than 6" DSH (defined below)
• Health or hazard assessments of trees larger than 6" DSH

What is DSH? 

DSH is Diameter at Standard Height, or the diameter of the tree trunk roughly 4-4.5 feet off the ground.

To measure this, start by measuring the circumference of the tree trunk at roughly 4-4.5 feet off the ground (just wrap a tape measure around the tree). Divide the circumference by 3.14 to get to the DSH.

What work does NOT require a registered TSP (though we'd strongly suggest still hiring one)?

• Pruning live branches smaller than 4" in diameter or less than 25% of the canopy.
• Pruning dead branches ("deadwood pruning") – an important safety practice, especially for larger mature evergreen trees that we highly recommend partnering with a registered TSP for given the riskiness of the work.
• Pruning of trees cultivated for fruit production
• Maintenance of hedges
• Removal of trees that are smaller than 6" DSH

Why do we recommend using a registered TSP for all tree work?

We recommend hiring a Registered Tree Service Provider for all tree pruning and removals, even when not strictly required by SDCI.

Working with a Registered Tree Service Provider increases the odds that you are getting advice from ISA-Certified Arborists and well-established companies with a history of excellence. 

To illustrate the significance of choosing a registered tree service provider, consider a scenario where you need deadwood pruning for a towering 100-foot Douglas Fir that overhangs your home. 

That work technically does not require a registered provider (as the branches are dead). But given the tree's size & inherent risks involved in branch removal from such a height underscore the importance of selecting a professional company with both ISA-Certified Arborists on staff and robust insurance coverage. 

Similarly, young trees necessitate proper training for safe, healthy growth, making an ISA-Certified Arborist indispensable for such work. By selecting a registered tree service provider, you eliminate much of the guesswork regarding their expertise.

4. Tree Removal Tiers & Allowances

The updated tree code categorizes trees into four tiers, each subject to unique rules and restrictions:

• Tier 1 - Heritage Trees: This category comprises a specific list of historically-significant trees that receive special protection.
• Tier 2 - Trees with a Diameter at Standard Height (DSH) of 24" or Greater: 
  • However, certain tree species have lower size thresholds for Tier 2 protection. For instance, a Japanese Maple attains Tier 2 status at only 12” DSH, and a Sitka Spruce at only 6” DSH. It is imperative to collaborate with your arborist to confirm species-specific exceptions. 
  • Tier 2 also encompasses trees in a grove. 
  • Several tree species, such as Red Alder or Black Cottonwood, are less protected and are categorized as Tier 3, irrespective of their size.
• Tier 3 - Trees with a DSH of 12” or Greater, up to 24” DSH
• Tier 4 - Trees with a DSH of 6” or Greater, up to 12” DSH

Removal Allowances:

• Tier 1, 2, and 3 trees – tree removal is not allowed unless the tree is hazardous (as assessed by a TRA-qualified ISA-Certified Arborist). Other exceptions include dead trees, insect/pest/pathogen-infested trees, or trees interfering with ADA compliance.
• Tier 3 trees have an additional permitted exception for cases in which the tree is causing obvious damage to building foundation or utility infrastructure.
• Tier 4 trees are permitted to be removed, but only up to two trees in a three-year period. They can also receive permits for all the exceptions mentioned above.

In essence, as a homeowner with an already-developed property, removing any tree with a DSH of 12" or greater is not permitted unless there is a specific, permitted reason for removal.

Note - when trees are removed, the city will likely require replanting of new trees. The tree planting requirements are based on permit type and number of trees removed & remaining on the site.

5. Permitted Removals of Tier 1, 2, or 3 Trees

To remove Tier 1, 2, or 3 trees, specific permits from SDCI are required. Turnaround time is typically 2-6 weeks, depending on job complexity and SDCI's workload.

Blooma Tree Experts will handle all permitting processes and coordinate with SDCI to expedite approvals. Depending on the type of tree permit required, we will handle Arborist Reports, Tree Risk Assessments, Site Plans, and any follow-up Q&A with the city arborists/reviewers as part of our tree work permit filing service.

Below are a few of the key tree removal permits and their requirements:

• Dead/Dying Trees: 
  • No city filing fee is required (as of September 2023). 
  • Photos of tree required.
  • Arborist report or Tree Risk Assessment NOT required.
  • Site Plan required (will be created by our office team as part of our permit filing service).
• Insect/Pest/Pathogen-Infested Trees: 
  • City permit filing fee of $225.75 (as of September 2023). 
  • Arborist Report required (written by our ISA-Certified Arborists as part of our permit filing service). 
  • Site Plan required (created by our office team as part of our permit filing service).
• Hazard Tree: 
  • City permit filing fee of $451.50 (as of September 2023). 
  • Arborist Report required (written by our ISA-Certified Arborists as part of our permit filing service)
  • Tree Risk Assessment (TRA) required ( written by one of our TRA-Qualified arborists as part of our permit filing service). Please note that this TRA is a standardized form document from the International Society of Arboriculture and can only be filled out by an ISA-Certified Arborist with TRA qualification. 
  • Site Plan required (created by our office team as part of our permit filing service).
• Trees Causing Obvious Damage to Building Foundation / Utility Infrastructure: 
  • City permit filing fee of $225.75 (as of September 2023). 
  • Photos of tree showing obvious damage and a description of the building/infrastructure issue. 
  • It can help to have the specific contractor provide an explanation, such as a sewer contractor explaining why they can't fix a sewer line without tree removal.
  • Site Plan required (created by our office team as part of our permit filing service).

6. Public Notice Posting Requirements

To be clear, public notices are not permits, but they play a crucial role in tracking tree work throughout the city. 

As part of our tree service, Blooma Tree Experts will always create any required online public notices for your job and ensure physical posting at the job site during the work. There is no turnaround time for these permits (no city review), we can create them instantly.

One tip – let’s say we are definitely going to prune three trees for you, but you’re still debating if you want us to prune a fourth tree. 

In that case, you should have us price out the fourth tree pruning as optional work – that way we will de facto include it on our tree work public notice. If we don’t do that, you won’t be able to add the work on the day of the job, given it won’t be a part of the original public notice. So, get all trees you might want worked on priced out to give yourself the most flexibility on the day of the job.

Here are the posting requirements:

• Reportable Work = Tree Pruning >4" diameter live branches or >25% of the canopy: A notice must be created on SDCI’s online portal at least 3 business days before the start of work. On the day of work, the notice must be physically posted at the job site, visible from the right-of-way, and remain posted for 5 days afterward.
• Tree Removals >6" DSH: A posting notice must be created at least 6 business days before the start of work. On the day of the job, the notice must be physically posted on the job site, visible from the right-of-way, and remain posted for 5 days afterward.

Public notice and the 3-6 business day waiting period are not required for emergency work. However, as a best practice, our office team will email SDCI to provide a summary of the work completed on an emergency basis and the reasons for it. That way, if a neighbor complains or reports you for any reason, SDCI will already have a record of what work was completed and why.

Our office will create the online public notice when you book your job with us. Our crew will bring the physical notice to post on the day of your job.

7. Where to Read More

For in-depth information, please refer to the following resources from SDCI's websites:

• SDCI Webpage about Tree Removals
• Tip 242B: Tree Removal Requirements on Private Property
• Tip 242C: SDCI Tree Service Provider Registry
• Tip 242D: Tree Public Notice Requirements
• Director’s Rule 7-2023: Designation of Tier 2 Trees (includes a full list of lower size threshold Tier 2 trees)