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
The community forest overlaps many jurisdictional boundaries and impacts multiple departments. To simplify tree management, your tree ordinances should specify which staff have authority over trees. Depending on your community, this may be an urban forester, an arborist, a parks/planning/public works director, or a tree board.
In an ideal scenario, every government employee or contractor that works on trees is a credentialed tree professional. If that is not possible, communities can identify specific high-risk or high-expertise tree activities and require only those be conducted or supervised by a credentialed tree professional.
To accomplish this, the ordinance must define what it takes to be a “licensed tree professional” or “qualified arborist”. This is normally an entry in a Definitions section (often the second section after the Purpose section). The most common definitions require a professional who has obtained one of the following:
- ISA Certified Urban Forest Professional
- ISA Certified Arborist®
- Society of American Foresters Certified Urban and Community Forester
- Licensed landscape architect
- A specific experience requirement (i.e. 5 years working as an arborist)
- A specific municipal or state level certification
The ordinance must then list out which tasks or actions should only be completed by a credentialed tree professional, such as conducting tree inventories, writing tree protection plans, or assessing hazardous trees. The sample language and example ordinances below show three levels of complexity for defining who has authority over trees and delineating tasks to be handled by qualified tree professionals.
Key Definitions
Certified Arborist
An individual credentialed by the International Society of Arboriculture (ISA) or equivalent body, demonstrating expertise in tree care.
Tree Board
An advisory or administrative body appointed to guide urban forestry policy, review permits, and support community engagement.
Ecosystem Benefits
The essential contributions trees make to maintaining healthy, resilient, and livable environments for people, animals, and plants. Commonly, these benefits include improving air and water quality, regulating climate by absorbing carbon dioxide and releasing oxygen, moderating temperatures, reducing stormwater runoff and erosion, providing habitat and food for wildlife, supporting biodiversity, and offering cultural and recreational value such as shade, beauty, and spaces for community activities.
Example Language
Basic Level
Basic ordinances assign responsibility for tree oversight to a city department or official, sometimes without specifying qualifications. This ensures someone is accountable for tree care, even if specialized expertise is not required.
Basic
Authority
- The Public Works Director is responsible for administering and enforcing this ordinance.
- The Director may designate staff to oversee tree planting, maintenance, and removal.
Examples
Joplin, Missouri
Joplin, MO Code of Ordinances. Chapter 122, Sec. 122-122 . Accessed May 29th, 2025.
Clearfield, Utah
Clearfield, UT Code of Ordinances. Chapter 21 Landscaping Standards and Requirements, Sec. 11-21-9. Accessed May 29th, 2025.
Woodinville, Washington
Woodinville, WA Code of Ordinances. Chapter 2.24 Public Trees, Sec. 2.24.170. Accessed May 29th, 2025.
Intermediate Level
Intermediate ordinances require that tree-related decisions involve a certified arborist or trained staff, raising the standard of care and decision-making. This approach helps ensure tree health and safety are managed with professional knowledge.
Intermediate
Authority
- The City Arborist, who must be an ISA Certified Arborist, shall administer this ordinance and approve all tree permits.
- The City Arborist is authorized to conduct inspections and enforce compliance.
Examples
Hamilton, Ohio
Hamilton, OH Code of Ordinances. Chapter 915 - Comprehensive Tree and Planting Plan, Sec. 915.03. Accessed May 29th, 2025.
Ithica, New York
Ithaca, NY Code of Ordinances. Chapter 306 - Trees and Shrubs, Sec. 306-4. Accessed May 29th, 2025.
Pottstown, Pennsylvania
Pottstown, PA Code of Ordinances. Chapter 25 - Trees, Sec. Sec. 25-108. Accessed May 29th, 2025.
Advanced Level
Advanced ordinances mandate ISA-certified arborists or equivalent experts for all major tree decisions and empower them with permitting and enforcement authority. This maximizes technical accuracy, consistency, and public trust in tree management.
Advanced
Authority
- The Urban Forester shall oversee all public and private tree management activities using [Ordinance Chapter] and the regulations herein.
- The Urban Forester must be certified by the International Society of Arboriculture and is encouraged to pursue advanced credentials.
- The Urban Forester and/or their designee(s) shall review tree removal permits, landscape plans, and dedicate staff to a Tree Board for community engagement and education.
Examples
Green Bay, Wisconsin
Green Bay, WI Code of Ordinances. Chapter 28 - Parks and Recreation, Sec. 28-33. Accessed May 29th, 2025.
Milton, Wisconsin
Milton, WI Code of Ordinances. Chapter 26 - Environment, Sec. 26.76. Accessed May 29th, 2025
Aurora, Colorado
Aurora, CO Code of Ordinances. Chapter 26 Businesses, Article X. Accessed May 29th, 2025.