Seattle Tree Work Permitting Guide

What You Need to Know Before Pruning or Removing a Tree

Seattle has some of the most detailed and frequently updated tree regulations in the Pacific Northwest. These rules are designed to protect the city’s urban forest while still supporting smart development, housing growth, and environmental justice.

If you’re planning to remove or significantly prune a tree on your property, you may need a permit — depending on the tree’s size, location, condition, and how your project could impact the surrounding area.

When a Permit Usually Isn’t Required

You may not need a permit if you’re doing basic, routine care — but some documentation and notice requirements still apply if you’re hiring a professional tree service.

Permit-exempt situations include:

• Routine maintenance or light pruning following ANSI A300 standards

• Trees under 6 inches in diameter (measured 4.5 feet above ground)

• Trees that are dead, fully uprooted, or storm-fallen

• Removal of certain invasive or nuisance species

• Tree removal to make space for ADA accessibility improvements

• Note: Even when a permit isn’t required, you may still need to notify the city or post a public notice — especially when using a commercial tree service.

When a Permit Is Required: Seattle’s Tree Tier System

Seattle’s tree code uses a four-tier system to categorize tree importance and determine if removal or major pruning needs city approval.

Tier 1: Heritage & Exceptional Trees

• Includes officially designated Heritage Trees

• Removal is rarely allowed unless the tree is documented as hazardous

Tier 2: Large or Protected Species

• Trees ≥24 inches in diameter (DSH), or specific protected species

• Require additional review, even if part of a development project

Tier 3: Mid-Sized Trees

• Trees 12–24 inches in diameter

• May be removed with permission, depending on property and zoning

Tier 4: Smaller Regulated Trees

• Trees 6–12 inches in diameter

• Removal may be allowed more freely, but still subject to rules on some properties

Hazardous Tree Removal

Even if a tree poses a clear risk of falling, Seattle requires:

• Evaluation by a certified arborist with ISA Tree Risk Assessment Qualification (TRAQ)

• Documentation submitted to the city within 10 days after removal

• Replanting and follow-up care if it’s a regulated tree

Tree Work in Environmentally Critical Areas (ECAs)

ECAs include steep slopes, landslide zones, wetlands, shorelines, and other sensitive habitats. These areas are highly regulated.

What’s allowed without a permit in ECAs:

• Routine maintenance (up to 750 sq. ft.) including pruning and landscape care

• Emergency hazard tree removal (must submit documentation afterward)

• Invasive species removal using hand tools (up to 2,500 sq. ft.)

 Ballard Tree Service can help identify whether your property lies within an ECA — and what that means for your project.

Tree Replacement Rules

In most cases, when Tier 1, 2, or 3 trees are removed due to hazard, disease, development, or invasive species:

• Replacement trees are required

• Must match original canopy potential and be appropriate species for the site

• Site restoration is required — no replanting with invasives

• Ongoing care and records are required for 5 years, including:

  • Watering, photo documentation, and replanting failed trees

  • Replacement trees count toward Seattle’s Green Factor for sustainable development

  • Locations are tracked on the city’s online tree map

Need Help Navigating Seattle’s Tree Regulations?

Ballard Tree Service is a Seattle-registered and qualified provider. We stay up-to-date with current permitting rules, public notice requirements, and safety standards — so you don’t have to.