An introduction to practical tree preservation codes that balance development and canopy growth.

March 16, 2026  |  Written by Alec Sabatini

You’ve probably heard “a bird in the hand is worth two in the bush.” How about “a tree in the land is worth ten in the mush?” The latter is my attempt at a new tree preservation slogan. Not nearly as catchy, but the sentiment rings true.

Preserving an established urban tree provides orders of magnitude more ecosystem benefits than ten new trees planted as replacements (newly planted in soil AKA mush). A 30 inch tree can intercept 10X more air pollution, store 90X more carbon, and contribute 100X more leaf area than a 6 inch tree.

A well crafted tree preservation ordinance is a must-have for any community committed to protecting and growing a healthy urban forest. This blog will review the key ingredients in effective tree preservation codes, such as drawing the line on which trees earn protection, when removal is allowed, and how to replace lost canopy. The inspiration for this article comes from our 2025 webinar Policy in Practice: Tree Preservation Frameworks, which you can also check out for a deeper dive on this topic.

Key Ingredients of Tree Preservation

Every municipal tree ordinance should cover a few key topics. It must clearly delegate authority and responsibility over trees, often to an urban forester, parks, or public works official. The tree ordinance should define standards for tree management, such as planting specifications, protections during construction, and penalties for breaking the ordinance. The tree ordinance must also address tree preservation, and to do that requires the following components.

Protected and Heritage Tree Definitions

The ordinance must set a threshold for when a tree is valuable enough to earn protection. This is done by creating a definition of a protected tree (sometimes referred to as a significant tree), and is most commonly based on a certain diameter at standard height (DSH). For example, all trees over an 8 inch DSH that are not on the regional invasive species list qualify as a protected tree.

It’s also recommended to create a higher tier of protections for especially large and valuable trees. These are called heritage, specimen, landmark, or exceptional trees and often have DSH thresholds around 24 inches or larger. Cities often have a set list of species that earn this special status. In Lake Forest Park, Washington Bigleaf Maples over 42 inches or Western White Pines over 36 inches DSH are considered Exceptional Trees and require special permission for removal.

When regulations are confusing, it allows for a lot of error, and it allows for developers and tree removal companies to take advantage of that confusion

-Alex Hancock, PlanIT Geo

Tree Removal Permits

There should be a clearly defined permit system for residents to follow when they want to remove a “protected” tree and requirements for when a planned development will remove protected trees on site.

Individual Tree Removal

For an individual to remove a protected tree from their yard the process typically requires a submission of a permit through the municipal website. The ordinance language should specify the conditions needed to get approval for a removal, such as the tree’s condition, or the size or zoning class of the property in question. In Austin, Texas trees over 19 inches DSH are protected and a city arborist must inspect the tree and find it hazardous or preventing reasonable use of the property in order to approve removal.

Some communities, particularly in more forested areas, allow for a set amount of tree to be removed each year before permitting is required. There are also some states with preemptive legislation preventing cities from requiring tree removal permits on residential land. Even if private trees are not included, it is still important to establish a process where residents can request the removal of public trees, such as in the right-of-way adjacent to their property. Clearly defined approval criteria is key to keep the process transparent. In Coillerville, Tennessee, a public tree may be removed if it is dead or dying, damaging infrastructure, has an increased lean angle, or has been damaged in a storm.

Development-Based Removal

The majority of canopy loss happens during development. Accordingly, urban tree ordinance should be tightly integrated with planning and permitting. Requirements should be set for how many trees must be preserved through the development or redevelopment or a site. This requirement is normally triggered by a permitted activity, such as a grading or development permit.

There are lots of potential criteria to include in these requirements that can add flexibility and mold the ordinance in a way that works best for your community. For example, properties of certain sizes or zoning classes may have stricter requirements or be exempt from preservation requirements. For example, Meridian, Idaho exempts all detached single-family residential properties from tree preservation requirements.

It is most common for preservation to be stem-based, i.e. removing any protected trees during development requires a replacement at a 1 to 1 caliper inch ratio. The alternative is a canopy-based preservation approach. Fayetteville, Arkansas has canopy coverage minimums based on zoning classes. Single-family residential is set at 25% canopy cover, general industrial 15%, and the downtown core at 10%. If the development removes enough trees to dip below that cover threshold, then mitigation activities are required.

Mitigation

Mitigation requirements are your community’s method for recovering the value of removed trees. The best requirements strike a balance between discouraging superficial removals and recouping the loss of the healthy trees, while not putting too heavy a burden on new development. Mitigation actions are triggered when an individual or development needs to remove trees that qualify as protected.
This section can also be either stem-based or canopy-based. Stem replacement is usually has a scale based on the size of the tree removed, such as:

• 3 replacement trees for every 4- 8 inch DSH tree removed
• 6 replacement trees for every 9-12 inch DSH tree removed
• 9 replacement trees for every 13-20 inch DSH tree removed

Mitigation based on canopy requires a quantity of new trees that will sufficiently replace the area of canopy being removed, such as 12 new trees for every 10,000 sq ft. of contiguous canopy being removed. The tree preservation codes should establish replanting on the site of removal as the top priority. If the site owner can show that replanting on site is not feasible, off-site planting at city-approved location is the second priority. The last resort is a fee-in-lieu, commonly calculated as an amount per caliper inch of removed trees that are not being mitigated.

Exemptions and Incentives

To add pliability to tree preservation requirements make sure to include some strategic exemptions and incentives. Some standard exemptions to tree preservation include: trees that are identified as high risk, storm-damaged, invasive, or inhibiting utility operations. Some additional exemptions may be based around managing an ongoing pest or disease concern, allowing the municipality greater freedom to remove public trees, and exempting low-density residential properties.

Incentives are a way to encourage and reward developments that exceed minimum preservation requirements. A common mechanic is to count preserved trees towards required landscaping trees, with the option for larger preserved trees to count for more. Preservation incentives frequently offer greater flexibility for properties that go above and beyond for their trees. This could mean a reduction in building setbacks, parking areas, or landscape areas. It could also allow for a greater building height, density, or floor area ratio.

Incentives can also provide extra credit when the trees being preserved are especially valuable, such as heritage trees, contiguous canopy, trees that shade high-traffic areas, or trees that are integrated with green stormwater infrastructure. For communities that also want their tree ordinance to advance stormwater management and climate resilience, MARC’s Model Ordinances for Tree Protection, Weed Management, and Native Plant Encouragement show how to integrate trees into a broader green infrastructure code framework.

Implementation

Even the best-written tree preservation ordinance will fail without implementation capacity. When crafting your new or updated ordinance consider:​​

• Staffing and training needed to review permits, inspect trees, and enforce specifications, and penalize noncompliance.​​
• Software and data for tracking tree removals, mitigation, and canopy trends over time. Cities can pair their preservation efforts with tools like TreePlotter to keep careful tabs on how well the codes are working and if the canopy is being preserved as planned.
• Stay realistic on timelines. Drafting new ordinance language can take 6 months and it can take another 6–12 months after adoption for staff, developers, and residents to adapt to new changes.

How PlanIT Geo Supports Tree Preservation Ordinances

Explore more resources on municipal tree ordinances and urban forestry policy in PlanIT Geo’s resource library:

• Decode Municipal Tree Ordinances (on-demand webinar)​
• From Canopy to Policy: Turning Tree Canopy Data into Effective Tree Policy (Guide)​
• Private Tree Ordinance 101 (companion blog)​

For help reviewing or writing your tree preservation ordinance, connect with the PlanIT Geo team.