How Seattle Handles Tree Protection: A Practical Guide

Every city handles tree protection a little differently. In Seattle, Washington, there are 5 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Protected Tree Species

Seattle's overhauled Tree Protection Ordinance, SMC 25.11 (effective 2023), creates a tiered system. Tier 1 exceptional trees, Tier 2 heritage trees, and Tier 3 trees over 12-inch DBH need permits and replacement.

Key details: Code: SMC 25.11 (2023). Tiers: 4 categories. Tier 3 threshold: 12-inch DBH. Replacement cost: $2,833/inch DBH. Authority: SDCI.

Unpermitted Tier 1-3 tree removal: $1,000 base fine plus $2,000 per inch DBH replacement. Tier 1 violation can exceed $50,000. SDCI may revoke development permits for tree-code violations.

This is not one of those rules that cities tend to ignore. Seattle actively enforces its protected tree species requirements.

Tree Removal Permits

Seattle requires permits for removal of most significant trees under SMC 25.11, with strict protections for trees over 6 inches in diameter and enhanced rules for exceptional trees (24 inches or larger) on both developed and undeveloped lots.

Key details: Governing Code: SMC 25.11 – Tree Protection Ordinance. Tier Classification: Tier 1 (6-12 in), Tier 2 (12-24 in), Tier 3/Exceptional (24+ in). Exceptional Tree Fine: Up to $23,000 per tree for illegal removal. Tier 2 Fine: Up to $11,500 per tree for illegal removal. Replacement Required: Replacement planting at prescribed ratios.

Illegal tree removal can result in fines up to $11,500 per tree for Tier 2 trees and up to $23,000 per tree for exceptional trees. Additional penalties include required replacement planting at prescribed ratios and potential stop-work orders on associated development projects.

This is one of the stricter rules in Seattle's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

Tree Replacement Requirements

Seattle requires replacement planting when trees are removed, with ratios scaled by the size and tier of the removed tree under SMC 25.11, and an in-lieu payment option when on-site replanting is not feasible.

Key details: Tier 1 Replacement: Generally 1:1 ratio for 6-12 inch trees. Tier 2 Replacement: 2:1 to 3:1 ratio for 12-24 inch trees. Exceptional Replacement: Highest ratios for trees 24 inches and larger. In-Lieu Payment: Available when on-site replanting is not feasible. Establishment Period: Replacement trees must survive minimum 3 years.

Failure to plant required replacement trees after permitted removal can result in fines and additional enforcement action. Removing trees without proper replacement planning may result in retroactive penalties calculated at enhanced ratios. Trees removed illegally face the highest replacement requirements plus monetary penalties.

This is not one of those rules that cities tend to ignore. Seattle actively enforces its tree replacement requirements requirements.

Heritage & Protected Trees

Seattle Municipal Code 25.11, overhauled in 2023, classifies trees into four tiers. Tier-1 (Exceptional) trees 24+ inch DBH and Tier-2 trees 12–24 inch DBH are highly protected. Removal requires a SDCI tree permit, certified arborist report, public notice, and in-kind replacement or in-lieu fee under the new ordinance.

Key details: Tier-1 (Exceptional): 24-inch DBH or designated heritage. Tier-2: 12–24 inch DBH significant trees. Permit: SDCI tree-removal permit required. Heritage Tree program: Council-designated specimens. In-lieu fee: $2,833 per caliper inch (2024 rate).

Removing a Tier-1 or Tier-2 tree without a permit triggers civil penalties up to $5,000 per tree per day plus the appraised value of the tree under SMC 25.11.090. Exceptional and Heritage Tree violations are doubled. Permit applicants who damage retained trees during construction forfeit their tree-protection bond and may face stop-work orders.

This is not one of those rules that cities tend to ignore. Seattle actively enforces its heritage & protected trees requirements.

Tree Ordinances

Seattle has a comprehensive tree protection ordinance (SMC 25.11) that regulates removal of significant trees on both public and private property. Trees 6 inches or larger in diameter generally require a permit to remove. Exceptional trees receive the highest protection.

Key details: Governing Code: SMC 25.11 (Tree Protection). Significant Trees: 6 inches+ diameter — permit required for removal. Exceptional Trees: Generally cannot be removed. Penalties: Up to $11,500 per tree ($36,000 for exceptional).

Unauthorized removal of significant trees can result in fines of up to $11,500 per tree. Removal of exceptional trees without a permit can result in penalties of up to $36,000 per tree. Required replacement plantings and restoration may also be ordered.

Compared to other cities, Seattle takes a harder line on tree ordinances. The enforcement and penalty structure reflects that.

The Bottom Line

Seattle is tougher than many cities when it comes to tree protection. Out of the 5 rules covered here, 5 are rated strict. If you are a homeowner, renter, or business owner in Seattle, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

These rules come from Seattle's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.