If you’re considering an addition to your Portland home, you’ve likely encountered the city’s tree protection laws. While these regulations might seem restrictive at first glance, they don’t have to limit your renovation dreams.
At Lamont Bros., we’ve guided numerous Portland homeowners through these regulations, developing creative solutions that both preserve trees and achieve desired home expansions. Through years of experience, we’ve discovered flexible approaches that satisfy both the city’s requirements and our clients’ vision.
In this guide, we’ll explore Portland’s tree protection laws and outline practical solutions for your home addition. You’ll learn:
- Why Portland has tree protection laws
- Three options for planning an addition around a tree
- Remodeling best practices for following tree protection laws
Related Reading: Learn More About Home Additions
What Are Portland’s Tree Protection Laws?
In response to growing concerns about tree removal during development and inconsistent regulations in the early 2000s, Portland established the Title 11 Tree Code in 2015. This comprehensive law focuses on protecting large, established trees within city limits, specifically those exceeding 12-inch diameter at breast height (DBH). Trees smaller than 12 inches can be removed without permits.
While the Tree Code adds considerations to home improvement projects, its benefits extend beyond preservation. Large trees enhance property values across neighborhoods and provide vital environmental benefits to urban areas. For homeowners planning additions or remodels, understanding these regulations is key to successful project planning.
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How Tree Protection Laws May Affect Your Remodel
When you’re planning a home construction project, addition, or remodel in Portland, you’ll need to follow the Title 11 Tree Protection Code. To make the process easier and more accessible to everyone, there are a few different solutions to choose from. Each one has its merits depending on your specific situation. Read each option carefully to determine which might work best for your project.
Prescriptive Approach
The prescriptive approach offers easy-to-follow guidelines, but the rules tend to be more restrictive in what you can and can’t do. It establishes a tree root protection zone around the tree. The protection zone is a circular area that extends from the trunk one foot for every inch of tree diameter. So, a tree with a diameter of 20 inches would have a protection zone with a 20-foot radius.
Title 11 code stipulates that the tree protection zone must be marked and protected by a barrier, such as a chain-link fence. Construction activity may advance into the root protection zone no more than half of the radius. In other words, with a 20-foot protection radius, construction activity could be no closer than 10 feet to the tree. Additionally, construction activity may not take up any more than 25% of the total protected area.
In addition to these restrictions, there is a list of specific activities which are totally prohibited within the protection area. The list from the City of Portland’s website includes:
- ground disturbance
- construction activity involving vehicle or equipment access
- storage of equipment or materials
- temporary or permanent stockpiling
- proposed buildings
- impervious surfaces
- underground utilities
- excavation or fill
- trenching
- in-ground irrigation systems
- other work activities
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Arborist Report
Let’s say you’re doing an addition to your home, and there’s a 24-inch tree in your backyard. By the prescriptive rules, you can’t build closer than 24 feet to the tree. Problem is, your planned addition sticks 10 feet into the root protection zone. Is all hope lost? Not necessarily. In this case, you’re better off abandoning the prescriptive approach for a more customized solution.
Why hire an arborist?
Sometimes, the constraints of a home remodel or addition prevents the prescriptive approach from being viable. In cases where it isn’t possible to establish the necessary root protection zone established by the Title 11 Tree Code, homeowners may legally choose to take the performance path. This option tends to be more expensive and typically adds about 5% to the total cost of a project. However, it provides substantially more flexibility in what work can be done around the tree.
The performance path is a set of alternative tree measures designed for projects that require more leeway. Although more expensive in its initial phases, a customized tree protection plan may prove beneficial in the long run. It requires the design and construction team to consult with a professional arborist to put together a site-specific protocol.
The arborist’s job is to assess the tree’s tolerance to construction activity and plan accordingly. Their plan must address specific protective measures and justify how these measures will preserve the integrity and health of the tree. So long as the customized plan provides adequate protection to the tree, construction activities may take place much closer.
