Maintain Trees

Property owners are required to maintain trees on their property including those in and adjacent to public right-of-ways to:

• Keep trees in good health ( this includes watering, pruning, and protecting against damage and disease).
• Keep tree branches trimmed to meet clear zone standards.

Routine removal of dead or dying branches can be done at any time. Flowering trees should be pruned after blooming. The best time to trim living branches is late in the dormant season or very early spring before leaves form. 

Tree Removal and Planting 

Obtain a Permit Before Removal or Planting

Property owners are required to replace any trees removed from the public right-of-way. Property owners are also required to obtain a free Tree Care Permit from the City of Hillsboro before: 

• Planting, removing, or replacing a street tree
• Major tree pruning within the public right-of-way
  • Major pruning is defined as pruning in a manner that causes the removal of branches two inches in diameter or greater, removal of roots two inches in diameter or greater, or removal of branches constituting more than 20 percent of the crown (Hillsboro Municipal Code Section 9.18.020)
• Pruning or tree care that impacts pedestrian or vehicle travel

Follow Design and Construction Standards

When planting a public street tree, property owners are required to follow the City of Hillsboro's Design and Construction Standards: 

• Section 700 Landscaping: Includes the approved list of tree species, spacing standards, and more.
• Appendix A Street Tree Planting Standard Drawing (Page 106): Includes tree planting procedures, approved root barriers, and more.

Clear Zone Standards

Sidewalks 

This includes: 

• Private trees and vegetation extending into the sidewalk, and
• Public street trees and vegetation planted along streets.

To learn more about additional sidewalk responsibilities, visit our Sidewalks webpage.

Streets and Alleys 

Property owners are required to trim or remove any tree limbs or vegetation hanging lower than 15-feet above the surface of the street or alley. This includes: 

• Private trees and vegetation extending into the street or alley
• Public street trees and vegetation planted along streets 

Street Signs

Property owners are required to trim or remove any tree limbs or vegetation blocking the visibility of traffic signs. This includes private trees, public street trees, and vegetation.

Intersections

Property owners on corner lots are required to trim trees and vegetation to create a clear line of sight at intersections for the traveling public.

• For residential properties with a sidewalk, the trimmed area is required to be a 25-foot triangular shaped area measured from the property line corner.
• For residential properties where it is difficult to see where the property line corner is located, the trimmed area is required to be at least a 35-foot triangular shaped area measured from the intersection.

 The triangular shaped area includes:

• Trees and vegetation along the street side of their property line (the public right-of-way)
• Trees and vegetation behind the property line

Property owners are required to trim vegetation so that the height is no more than:

• 30 inches above the top of the curb in locations with a curb
• 36 inches above the surface of the road in locations without a curb

Property owners are also responsible to trim tree limbs that hang lower than 10 feet anywhere in the intersection triangle. 

Learn more about when a free General Right-of-Way Permit is required before pruning in the Tree Care, Planting, and Removal section above. 

Tree and Vegetation Care Compliance

In cases where the City identifies a need for property owners to trim trees or vegetation to meet Hillsboro Municipal Code, property owners will be notified with a door hanger.

The property owner is required to comply or contact the City to discuss scheduled trimming within 15 calendar days of receiving notification. If this does not occur, the City of Hillsboro Code Compliance Division will take steps to address the code requirements.

The City is responsible for:

• Planting, pruning, and removing public street trees and vegetation in medians, islands, and roundabouts located within the public right-of-way, which adjacent property owners are not required to maintain
• Performing any planting, maintenance, and tree removal in the public right-of-way in accordance with the Hillsboro Municipal Code, Design and Construction Standards, and established national tree care standards

The City retains the authority to:

• Trim or remove any trees and vegetation within the public right-of-way that could affect public safety or the use of existing sidewalks or roadways
• Trim or remove any trees and vegetation to allow the planned establishment, extension, expansion, widening, or improvement of public roadways, alleys, and pathways within public rights-of-way

In the event a private tree could affect public safety, the City will take the following steps:

• Attempt to contact the property owner to gain access to their property
  • If contact is made and permission to access the property is granted, City staff will trim the tree to the national tree care standards
  • If contact is not made, City staff will trim the tree to the property line and a door hanger will be left informing the property owner of the trimming. After receiving permission to access the private property, City staff will return and complete the trimming.

• Read the Hillsboro Municipal Code.
• Learn more about tree watering best practices and the City of Hillsboro’s Tree City USA program.
• Watch tree trimming videos by the Arbor Day Foundation.

New Construction

During new construction, street tree planting will be included in one of the following permits: 

• Building permit for a single lot, 
• Public Infrastructure Permit when additional improvements are constructed (such as in a subdivision), or
• General Right of Way Permit in all other situations.

During the first two years, the street trees and other public landscaping will require maintenance assurance. Maintenance assurance is generally in the form of a maintenance bond for 100% of the cost of the landscaping. This is to ensure the plantings are well-established and any dead or dying plantings are replaced prior to the City accepting them as public landscaping.

Tree Care, Planting, and Removal

Obtain a Permit

When working on behalf of a private property owner, contractors and developers are required to obtain a free Tree Care Permit from the City of Hillsboro before:

• Planting, removing, or replacing a public street tree
• Major tree pruning within the public right-of-way
  • Major pruning is defined as pruning in a manner that causes the removal of branches two inches in diameter or greater, removal of roots two inches in diameter or greater, or removal of branches constituting more than 20 percent of the crown (Hillsboro Municipal Code Section 9.18.020)
• Pruning or tree care that impacts pedestrian or vehicle travel

When submitting a Tree Care Permit or General Right-of-Way Permit for the tree work, provide a certificate of liability insurance with coverage of $2M in general aggregate. The certificate should include the City of Hillsboro as the additional insured.

Follow Design and Construction Standards

• Section 700 Landscaping: Includes the approved list of tree species, spacing standards, and more.
• Appendix A Street Tree Planting Standard Drawing (Page 106): Includes tree planting procedures, approved root barriers, and more.

Replace Trees

Contractors and developers are required to replace any trees removed from the public right of way.

Adult Elm Seed Bugs have a dark chocolate body with a downward facing-triangle on their back and emit an odor when crushed or smashed. While the bugs are not native to Oregon and can be a nuisance in summer and fall, they pose no threat to human health, plants, or structures. 

Simple efforts like keeping your yard free of leaves and debris, sealing entrances and windows, and inspecting firewood before bringing it inside can help prevent Elm Seed Bugs from entering your home. 

Two City programs help remove elm seeds from streets and established ditches. 

1. Street Sweeping Program: Streets are swept once a month.
2. Fall Leaf Collection Program: Leaves placed near the roadway will be picked up and established ditches will be cleaned. This program is scheduled to begin in November.

To learn more, read our Elm Seed Bug Pest Management flyer.

Photo provided by Bradley Stokes (University of Idaho Extension Service).

Emerald Ash Borer(EAB) 

The emerald ash borer (EAB) was first found in the United States in 2002, outside Detroit, Michigan. The beetles have since killed hundreds of millions of ash trees, mostly in the Midwest and on the East Coast. 

These invasive beetles were recently discovered in the Forest Grove area. While Oregon ash tree species have built up chemical defenses to native insects, they cannot defend against the emerald ash borer.

Emerald ash borer larvae eat a tree from the inside out, feeding on inner bark and restricting the plant’s ability to transport nutrients and water until the tree dies. The metallic green beetles then emerge from ash trees, leaving D-shaped holes behind.

A tree has almost no chance of surviving after it is infested. Because EABs spread so quickly, they are now considered the most destructive forest pest ever seen in North America.

Here is how you can help prevent the spread of emerald ash borers:

• Identify the pest: Inspect Ash trees in and around your property to help prevent the spread of EABs. The shiny green adult borers are often in or around infected trees in summer.
• Learn the signs and symptoms of EAB infestation: D-shaped exit holes, basal shoots, dead treetops and S-shaped patterns under the bark from where larvae feed are some visible symptoms.
• Understand treatment options and act early: The good news is healthy ash trees can be protected against EAB. For a complete list of insecticides and their effectiveness, see the Oregon Statewide EAB Readiness and Response Plan.
• Report an infestation: The Department of Forestry is asking Oregonians to report sightings of the emerald ash bore to the Oregon Invasive Species Council. You can call the hotline at 1-866-INVADER or report it at oregoninvasiveshotline.org. 

The state also recommends people avoid transporting firewood, which can carry emerald ash borers and larvae from place to place.

Learn more: 
Forest Facts: Emerald Ash Borer (EAB) Agrilus planipennis Fairmaire 

Parks & Recreation EAB webpage

• A private tree is a tree whose trunk is entirely on private property. 
• A public street tree is a tree located in the public right-of-way.

The public right-of-way is the area between the private property lines on either side of the street. This area may include a sidewalk, trees, vegetation, curbs, and roadway surface.

Property owners are responsible to maintain trees and vegetation growing from or into this area according to the requirements outlined in the Hillsboro Municipal Code.

In cases where the City identifies a need for property owners to trim trees or vegetation to meet Hillsboro Municipal Code requirements, property owners will be notified with a door hanger.

The property owner is required to comply or contact the City to discuss scheduled trimming within 15 calendar days of receiving notification. If this does not occur, the City of Hillsboro Code Compliance Division will take steps to address the code requirements.

The Pacific Northwest Chapter of the International Society of Arboriculture (PNW-ISA), an organization for arborists and urban foresters, provides guidance on when to plant and prune trees.

• Planting a deciduous tree in our area is recommended generally between November and April. They advise community member to avoid planting trees when the ground is frozen or during hot, dry weather.
• Pruning
  • The best time to prune living branches is late in the dormant season or very early spring before leaves form.
  • Flowering trees should be pruned after blooming.
  • Routine maintenance pruning of dead or dying branches can be done at any time.
  • Some tree species may be an exception to these general rules.

Trees have a positive impact on both air and water quality in our community.

Trees improve air quality by:

• Producing oxygen
• Absorbing carbon dioxide and pollution from the air

Trees improve water quality by:

• Intercepting rainfall, which reduces flooding and pollution from runoff
• Fostering groundwater recharge
• Stabilizing soils