Tree protection laws in Portland: How do they affect my home addition?

If you’re planning on an addition or remodel in your Portland home, you probably already know about the tree protection laws in Portland. Given their restrictions, you might initially think these laws prevent you from being able to build what you want. Fortunately, this isn’t necessarily the case. 

As one of Portland’s top remodeling firms, our team at Lamont Bros. has helped local homeowners work through Portland’s tree protection laws dozens of times. Although initially intimidating, there are several flexible solutions that can help you design and build your dream addition while also preserving the trees on your property.

This article will discuss everything you need to know about Portland’s tree protection laws so you can plan your addition accordingly. Once you’re done reading, you should have a much better understanding of the options available to you. You can expect to read about:

What are Portland’s tree protection laws and why do they exist?

It might seem a little tongue-in-cheek that a city nicknamed “Stumptown” has laws in place to protect trees from damage due to construction. But in the early 2000s, many Portland residents began to voice concerns over the number of trees being cut down for land development. At the same time, many conflicting or inadequate regulations caused confusion for builders and developers who didn’t know which set of rules to follow when planning for tree protection.

In 2015, the City of Portland implemented the Title 11 Tree Code. These city-wide laws are designed to protect and preserve the area’s tree growth through a set of construction guidelines. The primary purpose of these laws is to discourage damaging large and old-growth trees within city limits. As a result, protective measures apply to trees larger than 12-inch diameter at breast height (DBH). Trees smaller than 12 inches are not subject to the Tree Code laws and can be removed without a permit. 

Although the Tree Code can add extra complexity to home remodel or addition projects, it does provide benefit to the community as a whole. Large, old-growth trees can increase the property value of a home. Protecting them on a city-wide scale preserves the overall property value of the area. The more big, old trees there are, the more the homes are worth. Not to mention, the environmental benefits alone are worth protecting old-growth trees in urban areas.

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

Root Protection Zone Diagram. From City of Portland

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

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.

Additional solutions

AirSpade Working Demonstration

One option available to the arborist is to specify pneumatic excavation. Also known as “air spading,” this process uses compressed air to safely excavate the area around the tree. 

Arborists will often use pneumatic excavation to map out the tree’s root system. It exposes major tree roots so you and your contractors know what areas to avoid during construction. This is important because below-ground foundations, such as basements or crawl spaces, may pose a danger to a tree, or vice versa. Installing a foundation too close to a tree may require you to cut away several major roots. This in turn can severely damage or destroy the tree. At the same time, the tree will likely continue to grow over time, and the pressure from its roots may damage your foundation over the years. 

The alternative solution is to expose the tree’s major roots and install structural pillars in the ground around them. The addition structure can then sit on top of these footings without requiring a full foundation. Our team at Lamont Bros has used this method while designing additions to protect both the home and the tree. 

Removal Fee

If you decide you simply do not want to deal with Title 11 laws, there are options for removing a protected tree. The City of Portland requires homeowners and developers to acquire a removal permit to cut down protected trees. However, the cost is often exorbitant, with some tree removal fees reaching up to $25,000. 

To avoid incurring unnecessary costs and preserve the value of your property, it’s almost always best to opt for protective measures over removal. There are only a few scenarios where removing a tree is the best option. One is if your proposed addition sits directly on top of a tree’s current location.  The other is if the tree in question is unhealthy or threatens to fall on the existing building. 

Best practices for working with Portland tree protection laws

When working through the process of implementing a tree protection plan, there are a few important things to keep in mind. Below are some helpful tips to help keep the process easy and inexpensive.

Start your research now

It helps to be prepared when going into a project that requires tree protection. One of the best things you can do for yourself is to stay informed on the laws and regulations that could affect your remodel. 

One of the first things to do is take note of the trees in your yard that might fall under protected status. The best way to accomplish this is by measuring the trees yourself. You’ll need to take note of any large trees with a diameter larger than 12 inches.

The best way to find a tree’s diameter is to measure its circumference (the distance around the outside of the tree) at the height of your collarbone. Divide the circumference in inches by pi (3.14), and you’ll have your diameter.

Once you know which trees in your yard might be subject to Title 11 regulations, spend some time reading up on the law. The City of Portland website has several resources you can use to educate yourself on tree protection measures. 

Use a Design/Builder who is in Portland’s FIR program

For most construction projects, inspections, reviews, and permits are handled by several different people. One of the best things about remodeling in the Portland area is the Field Issuance Remodel (FIR) program. When you work with a FIR-certified contractor, the City of Portland assigns a single person to serve as the point of contact for design plan reviews, site inspections, and permit issuance. 

Why does this matter? The Title 11 Tree Code is over 100 pages long. It’s a long and complex document that can be difficult to read and understand how it applies to your remodel, specifically. By working with the FIR program, your dedicated project inspector can help to interpret the law as it relates to your project. 

Work with a professional design team

Tree protection is a complicated process on its own. Combine that with trying to design and construct a home remodel or addition on your own, and it’s a nightmare. A professional remodel design team can work directly with the City of Portland to establish a tree protection plan without putting you through the wringer. 

Chances are, an experienced designer has been through the process of designing a remodel with tree protective considerations. Instead of having to worry about making sure your remodel designs follow Title 11 laws and risking thousands in fees, you have a team of professionals to do the technical work. That way, you can focus on what really matters: working with your team to design a space where you can thrive.

Want to talk to a remodel designer about your addition?

Now that you’re more familiar with what to expect when remodeling your Portland home around protected trees, take the next step! Our website has tons of useful resources for homeowners thinking about remodeling. Check out our Additions Portfolio to get more information and inspiration for your next project!
Thinking about a home remodel or addition, but concerned about the trees in your yard? Don’t be! At Lamont Bros., we can help you work with the City of Portland to remodel your home and protect your trees. Click the link below to schedule a free video call with a member of our design team.

Featured Image: Billy Hathorn, CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0, via Wikimedia Commons