Assessment Results

Mitigation

Requirements to replant trees on-site, off-site, and/or contribute to a mitigation fund to help replace removed trees. 

Before reviewing your results, verify how your state governs local authority. States follow either Dillon’s Rule, which limits municipalities to powers explicitly granted by the state, or Home Rule, which allows broader local authority unless specifically prohibited by state law. If you’re in a Dillon’s Rule state, your tree ordinance must follow state-enabling legislation. Check your state statutes, municipal league, or community forestry program to confirm your state’s model.

When developing or revising a tree ordinance, we recommend you work with your community’s legal counsel. Legal counsel will help ensure your ordinance complies with state and local requirements, properly establishes enforcement authority, and can achieve your community's goals, while avoiding potential legal challenges.

Introduction

If a healthy, mature street tree is removed, will anything replace it? The mitigation requirements of a tree ordinance are a mechanism to replenish the loss of trees, canopy, and associated tree benefits through new tree plantings. At the Basic level, mitigation requirements often only apply to public trees. The Moderate and Advanced levels will detail the different ways private tree mitigation can be structured.  

Mitigation requirements are often based on the diameter of the removed tree(s) (i.e. a 1 for 1 inch replacement). Another strategy, which attempts to equal the benefits lost by the removed tree, is to require plantings that will recreate the area of canopy being lost after a set amount of time. Mitigation requirements also frequently have a priority system, where the first priority is to plant trees on the site where trees are being removed, the second priority is to plant at an approved off-site location, and the final option is to pay a fee-in-lieu, usually into a government tree planting fund.  

Key Definitions

Mitigation Ratio

The required number of trees plant per removed tree (e.g., 3:1 for heritage trees, 1:1 for protected trees).

Replacement Tree

A nursery-grown tree of species from the Approved Species List, meeting minimum size (e.g., 2.5" caliper).

In-Lieu Fee

A monetary contribution to a municipal tree fund, required if onsite replanting is infeasible (e.g., $500 per diameter inch removed).

Tree Fund

A special account set up by a city or town to collect money for planting, protecting, and caring for trees. Money in a tree fund can come from donations, penalties, or fees, and is used to plant new trees or replace ones that have been lost.

Example Language

Basic

Basic Level

Basic ordinances require simple ratio replacement of removed trees (typically 1:1 or 2:1), making mitigation straightforward and easy to enforce. This helps maintain minimum tree numbers in the community. This tier is easy to administer but may not adequately address ecological loss or urban canopy goals. 

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Basic

Mitigation Requirements for Removal of Street Trees

  1. Replacement Requirement: For each street tree removed by the adjacent property owner, two replacement trees of at least 2-inch caliper shall be installed in its place, on-site or at another site on public property. 

  2. Timeline: Replacement trees must be planted within 90 days of removal. 

  3. Exemptions 

    1. No mitigation is required for removal of dead, diseased, or hazardous trees as determined by the City Arborist. 

    2. No mitigation is required for invasive species. 

    3. No mitigation is required for street tree removal by utility companies. 

Examples

Ocoee, Florida

Ocoee, FL Code of Ordinances. Chapter 45 - Arbor Code, Sec. 45-14. Accessed May 29th, 2025. 

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Macon-Bibb County, Georgia

Macon-Bibb, GA Code of Ordinances. Chapter 17 - Parks and Recreation, Sec. 17-36. Accessed May 29th, 2025. 

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Meridian, Idaho

Meridian, ID Code of Ordinances. Article B - Landscaping Requirements, Sec. 11-3B-10. Accessed May 29th, 2025. 

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Intermediate Level

Intermediate ordinances allow for off-site mitigation, in-lieu fees, or higher replacement ratios for larger or heritage trees, providing flexibility and greater ecological benefit. Requires documentation and maintenance, and begins to address species selection and urban forest management goals. This tier balances enforceability and ecological benefits, suitable for communities with moderate urban forestry resources.

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Intermediate

Mitigation Requirements for Removal of Protected Trees 

  1. Replacement Ratio: For each protected tree that is removed, the property owner shall provide replacement trees at a 1:1 ratio: for every inch of DBH removed an inch of caliper is replanted. 

  2. Mitigation Options: For each protected tree removed, the permittee must replant in the following order: 

    1. On-site Planting: Replacement trees must be planted on the same property where removal occurs, unless site constraints prevent it. 

    2. Off-site Planting: If on-site planting is not feasible, trees may be planted on public land or another approved location. 

    3. In-Lieu Fee: If neither on-site nor off-site planting is feasible, the applicant may pay an in-lieu fee to the City Tree Fund, calculated per inch DBH removed. 

  1. Mitigation Plan: An approved mitigation plan is required, and must include: 

    1. On-site and off-site mitigation. 

      1. Reason for removal 

      2. Tree survey showing the locations, species, and DBH of trees planned for removal and replacement trees 

    2. In-Lieu Fee:  

      1. Reason why on-site and off-site mitigation aren’t possible 

      2. Proof of fee payment 

  2. Planting Standards: Replacement trees must be:  

    1. Selected from the City’s approved species list 

    2. At least 2.5 inches caliper 

    3. Planted within 90 days of removal 

    4. Maintained by the property owner for at least one year 

  3. Exemptions 

    1. No mitigation is required for removal of dead, diseased, or hazardous trees as determined by the City Arborist. 

    2. No mitigation is required for invasive species. 

    3. No mitigation is required for street tree removal by utility companies. 

Examples

Herdon, Virginia

Herdon, VA Code of Ordinances. Chapter 78 - Zoning, Sec. 78-111.2. Accessed May 29th, 2025. 

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Hackensack, New Jersey

Hackensack, NJ Code of Ordinances. Chapter 162 - Trees, Sec. 162-8. Accessed May 29th, 2025. 

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Winter Haven, Florida

Winter Haven, FL Code of Ordinances. Article III - Development, Design, and Improvement Standards, Sec. 21-185. Accessed May 29th, 2025. 

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Advanced Level

Advanced ordinances use differentiated ratios for standard, specimen, and heritage trees, integrate canopy coverage or ecosystem service restoration, and prioritize native species, climate-adaptation, and species diversity. They include robust maintenance, monitoring, and enforcement requirements, as well as equity considerations (e.g., planting in underserved areas). A Tree Fund is often utilized as a method of administering the fees and fines collected from mitigation requirements. The advanced tier of mitigation is extremely detailed and resource-intensive, but maximizes urban forest resilience, equity, and long-term sustainability.  

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Advanced

Mitigation Requirements for Removal of Protected Trees 

  1. Mitigation Calculation

    1. Standard Trees: For each protected tree removed, provide replacement trees at a 2:1 ratio or inch-for-inch DBH replacement. 

    2. Specimen/Heritage Trees: For removal of specimen or heritage trees, provide replacement at a 3:1 ratio (3 replacement trees for every 1 removed) or 2:1 DBH ratio (two inches of DBH planted for every 1 inch removed). 

    3. Canopy Coverage: If the property is subject to canopy coverage requirements, mitigation shall restore or exceed pre-removal canopy area within 20 years. 

  2. Mitigation Options 

    1. On-site Planting: Replacement trees must be planted on the same property, prioritizing native and climate-adapted species, and maintaining species diversity (no more than 10% of any one species). 

    2. Off-site Planting: If on-site planting is not feasible, trees may be planted in designated public spaces or conservation areas, with a maintenance agreement. 

    3. In-Lieu Fee: If planting is not feasible, an in-lieu fee based on the appraised value of the removed trees shall be paid to the City Urban Forest Fund, used for planting and maintaining trees in underserved neighborhoods. 

  3. Planting and Maintenance Standards 

    1. Replacement trees must be at least 3 inches caliper, planted according to ANSI A300 standards. 

    2. The property owner is responsible for maintenance and replacement of trees that die within three years. 

    3. The city may require a performance bond or financial guarantee to ensure survival. 

  4. Monitoring and Reporting 

    1. Annual reports on survival and health of replacement trees must be submitted to the city for three years. 

    2. The city will inspect and may require additional planting if survival rates fall below 80%. 

  5. Exemptions and Reductions
    1. Exemptions  

      1. No mitigation is required for removal of dead, diseased, or hazardous trees as determined by the City Arborist. 

      2. No mitigation is required for invasive species. 

      3. No mitigation is required for street tree removal by utility companies. 

    2. Reductions
      1. Mitigation may be reduced if removal demonstrably improves overall site ecology or biodiversity. 

Examples

Lake Forest Park, Washington Canopy-Based

Lake Forest Park, WA Code of Ordinances. Chapter 16.14 - Tree Canopy Preservation and Enhancement, Sec. 16.14.110. Accessed May 29th, 2025. 

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Austin, Texas

Austin, TX Environmental Criteria Manual. Section 3 - Tree and Natural Area Preservation, Sec. 3.5.4. Accessed May 29th, 2025. 

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Kirkland, Washington

Kirkland, WA Code of Ordinances. Chapter 95 - Tree Management and Required Landscaping, Sec. 95.23. Accessed May 29th, 2025. 

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