Trees & Codes

See also: Tree & Vegetation RemovalGreen Factor

What Is It?

Seattle’s Tree Protection Code, Seattle Municipal Code (SMC) 25.11, limits the number, size, and type of trees that may be removed from private property. These regulations help protect our urban forest. Urban trees provide numerous ecological, economic, and social benefits, including wildlife habitat, neighborhood livability, and improved public health outcomes. Maintaining our urban forest is a cooperative effort between property owners, developers, neighbors, and the City. 

This webpage contains information to help you understand Seattle’s tree regulations and provides resources and contact information related to trees, tree protection, and tree maintenance.

Seattle has new tree protection rules for property owners and tree service providers. Read the code and registry information below, and check out our summary flyer.

Our tree protection requirements vary based on the size, species, and location of the tree and the current condition of the property where the tree is located. Certain trees are protected and may not be removed unless specific requirements are met. 

In order to determine the tree protection requirements for a specific tree or property, you need to have the following information: 

  • What is the size of the tree? 
  • Is the tree “exceptional”? 
  • Is the tree hazardous? 
  • Is the tree on undeveloped land, developed property, or developing property? 
  • Is the property within an environmentally critical area? 
  • Is the property within the Shoreline District? 

The information below can help you answer these questions and generally explains when and where the Tree Protection Code applies.  

Tree size. Tree size is stated as either DBH (diameter at breast height) or DSH (diameter at standard height), both of which are measured at 4.5 feet above ground.  

Exceptional trees. Exceptional trees are trees that are large for their species and therefore have particular historical, ecological, or aesthetic value. SDCI Director’s Rule 16-2008,Designation of Exceptional Trees, explains how we evaluate a tree for exceptional status based on size. Any tree over 30 inches in diameter, measured approximately 4.5 feet from the ground, is almost certainly exceptional. However, some species are exceptional at only 6, 12, 18, or 24 inches in diameter. We recommend that you consult a professional to determine if your tree is exceptional.  

Exceptional trees are protected by code and in most cases may not be removed, topped, or intentionally damaged. If you unlawfully remove an exceptional tree, the penalties can be expensive. If you are planning a construction project and your site contains large trees, please contact SDCI early to understand the protection requirements or opportunities for removal if certain conditions exist on your lot. 

Hazardous Trees. The Tree Protection Code allows for removal of hazardous trees, including hazardous exceptional trees. You must get SDCI approval before removing a hazardous exceptional tree. In most cases, we will only approve removing “high-risk” hazard trees. To determine if the tree or trees are a high-risk hazard, you must get a hazard tree assessment from either a certified arborist or a registered consulting arborist with the ISA tree risk assessment qualification and apply for a permit. See Tip 331B, Hazard Trees, for more details. For more information on applying for a tree removal, read How to Apply for SDCI Approval for Hazard Tree Removal and Vegetation Restoration. 

Undeveloped land. Undeveloped land is a parcel or lot that has no structures or no legally established land use.  

  • You cannot remove any tree (exceptional or non-exceptional) 6 inches or greater in diameter, unless the tree is designated as a high-risk hazard.  

Developed property. Developed property is a parcel or lot that has legally permitted structures or uses. 

  • You cannot remove any exceptional trees unless they are determined to be a high-risk hazard. 
  • You cannot cut down more than 3 non-exceptional trees 6 inches or greater in diameter each year unless the tree is designated a high-risk hazard. 

Developing property. If you are developing your property, you may remove trees if retaining them prevents you from achieving the allowed lot coverage or floor area of the site's land use zone. You must show that it's not possible to retain the trees by using various "departures" and “modifications” from the zone's land use code development standards (see SMC 25.11.060, 25.11.070, and 25.11.080). We will review your tree and vegetation plans as part of your permit application.  

Environmentally critical areas. If your property is on an environmentally critical area (ECA), the tree removal regulations are more restrictive. ECAs include: 

  • Landslide-prone critical areas 
  • Steep slope erosion hazard areas and their buffers 
  • Fish and wildlife habitat conservation areas 
  • Riparian corridors 
  • Wetlands and their buffers 

You can find out whether or not your property contains an environmentally critical area on our GIS map.  

You cannot remove any trees or otherwise modify vegetation from environmentally critical areas without an approved stand-alone ECA tree and vegetation plan or an ECA tree and vegetation plan approved with an issued building permit. 

An ECA tree and vegetation plan is commonly called a revegetation or restoration plan. You can find information about applying for a stand-alone ECA tree and vegetation plan by reading  How to Apply for SDCI Approval for Hazard Tree Removal and Vegetation Restoration. Tip 331,Environmentally Critical Areas - Tree and Vegetation Overview, and Tip 331A, Environmentally Critical Areas - Vegetation Restoration, provide useful information related to trees and vegetation in ECAs. 

Shoreline District. Tree removal in the Shoreline District must comply with the Tree Protection Code. In addition, in most cases you cannot remove any trees or vegetation from the Shoreline District without an issued Shoreline Exemption or issued building permit. The regulations on Shoreline District vegetation are found in SMC 23.60A.190. The Shoreline District is generally the land within 200 feet of a shoreline. You can find out whether your  property is within the Shoreline District on our GIS map. 

Zoning Standards and Trees. Depending on your project and its zoning, you may be required to comply with tree requirements in the zoning code. These requirements may include planting trees, preserving or planting trees to comply with Green Factor, or incentives to protect trees during your construction project such as decreased yards and setbacks. 

The Tree Service Provider Registry is an online database of registered tree service providers that meet the City’s criteria to conduct tree work in Seattle and are committed to understanding and following Seattle’s tree regulations.

Starting November 10, 2022, all tree service providers doing the following type of work in Seattle must be registered with the Seattle Department of Construction and Inspections (SDCI):

  • Removal of any tree over 6 inches in diameter.
  • Major pruning for any tree on private property. Major pruning is removing any branch or root 2 inches in diameter or greater, or the removal of more than 15% of the tree canopy. You do not need to be registered to complete other routine pruning and maintenance on trees.
  • Consulting services for trees including conducting tree assessments for an arborist report.

Property owners must use registered tree service providers and post a notice three days before the tree work is done. Tree service providers who are not registered with SDCI cannot do work in Seattle and may face penalties if they conduct work in Seattle without an approved registration. The tree service registry will be available after August 26, 2022.

Register Your Business

After August 26, Tree Service Providers can register for SDCI’s Tree Service Provider Registry on the Seattle Services Portal. It will take approximately 15-20 minutes to complete the Registry application. If you have questions regarding the registration process, please contact the Tree Service Provider Registry phone line at (206) 233-5185 or contact us through our 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. Please note that you must maintain your registration requirements in good standing for the duration of your registry term.

What You’ll Need

  • An active Seattle Services Portal account.
  • A current and valid City of Seattle business license. You will be asked to upload a copy of your business license.
  • A current and valid Washington State contractor registration under chapter 18.27 RCW (not required for businesses registering as consulting services only).
  • A current certificate of insurance with coverage of at least $1,000,000 Commercial General Liability Insurance and Commercial Auto Liability Insurance. You will be asked to upload a copy of the certificate.
  • At least one employee or a person on retainer who is a currently credentialed International Society of Arboriculture (ISA) certified arborist trained to conduct work according to American National Standards Institute (ANSI) Standard A-300 or its successor standard. You will be asked to upload a copy of the ISA Certification Card for each credentialed holder listed on your registry form. You will be asked to upload a copy of your ISA card.
  • An understanding of City codes applicable to commercial tree work.

Know the Code

All Tree Service Providers must follow the tree code (SMC 25.11). Tree Service Providers who do not follow the tree code may be removed from the Tree Service Provider Registry for one year. Both the property owners and the tree service providers may face financial penalties for tree code violations. Contact SDCI arborists early in the design process for assistance in balancing tree protection and development.  

Learn More

SDCI Arborists will host informational sessions in September and October to help you fully understand the regulations. These will be recorded and available on our website.

Please note that the SDCI tree service provider registry covers work on private property and is different from the SDOT tree service provider registry that regulates work that occurs in the public right-of-way. You must register on each one separately; links to each may be found on the Seattle Services Portal.

Starting November 10, 2022, property owners must post a public notice of major pruning or removal of trees on their property at least three days before a tree service provider starts the work, whether or not a permit is required. This notice is not required for trees removed as part of a tree and vegetation plan required inside of environmentally critical areas or for trees removed by the owner of a property.

We will provide more clarification on what is required to meet the notice requirements and a tool to help you create the public notice by early November, 2022.   

We encourage all applicants, property owners, contractors, architects, developers, and arborists to reach out to us with any tree questions as early as possible when planning a project. We are here to answer questions early in the design process to determine which trees are protected by code and how to accommodate them. We can also answer questions about trees outside of the development process. Our on-staff certified arborists can answer questions about tree protection requirements, be a resource for tree-related information, and improve customer experience when trees are involved in any permit process.

Contact Us

The best way to contact our staff is 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.

Meet Our Arborists! 

Paul Humphries has worked for the City of Seattle for 20 years and joined SDCI in September 2020. He is an ISA certified Arborist and Tree Risk Assessor, who is passionate about maintaining urban canopy and applying code to protect our beautiful city’s trees. Paul’s favorite tree is the Antarctic Beech. When he’s not at work, he can be found in the mountains hiking with his wife and their Great Dane or working in his garden.

Deborah McGarry started her career in urban forestry in New York in 2000 and never looked back. She has been with the City of Seattle for 15 years, working on street trees, park trees, and, for the past 3 years, private property trees with SDCI. She fervently believes that we need trees to keep our city livable and that dense cities and healthy trees are compatible. When not working, she loves adventures with her husband, 6-year-old daughter and 3-year-old son, exploring nature, gardening, and reading. 

Read the Code

For more information on existing regulations, read:

Other helpful resources include:

  • Common Seattle Trees, a helpful guide to identifying common trees, including exceptional trees.
  • Tree Protection on Construction and Development Sites is a good overview of tree care and protection measures during your construction project. As this is the Washington Department of Natural Resources' guidance, some details and requirements are different from ours. In those few situations, you need to follow SDCI's tree protection rules.

Recent Changes

On February 17, 2022, SDCI, in consultation with the Office of Sustainability & Environment (OSE), released SEPA Draft legislation to amend the Land Use and Tree Protection Codes. These updates are our response to the City' Council's direction to explore the strategies to increase tree protection to be consistent with the goals and policies of the 2015-2035 Comprehensive Plan and the 2020 Urban Forest Management Plan (UFMP). Those strategies were included in Council Resolution 31902, adopted September 16, 2019. A SEPA appeal was filed and the hearing was held on June 14, 15, and 22, 2022. We expect the Hearing Examiner’s decision in August 2022.  We will submit our final recommendations for this legislation to the Mayor and Council after the SEPA appeal decision. For more information, please refer to SDCI’s Tree Protection changes to code webpage.