Frequently Asked Questions about Proposed Updates to Portland’s Tree Code

Learn more about current efforts to update the City of Portland's tree code.

On this page

General Information on Title 11, Portland’s Tree Code

I’m looking for more information about the tree code requirements. Where can I find that?
The City’s tree code is broadly divided between non-development and development activities, and then additionally between trees on private property, trees on City property, and street trees. For more information on tree code requirements, visit www.portlandoregon.gov/trees. You can also see the tree code here.

Who is responsible for implementing the tree code?
Title 11 places the responsibility for implementation to either the Urban Forestry Division of Portland Parks & Recreation (PP&R) or to the Bureau of Development Services (BDS), based on the type of tree and situation. Each bureau may propose amendments to the sections of code it implements, subject to a final decision by the City Council.

SituationCity and Street TreesPrivate Trees
Non-DevelopmentPP&R Urban ForestryPP&R Urban Forestry
DevelopmentPP&R Urban ForestryBDS

When proposed amendments relate to development situations, both the Planning and Sustainability Commission and the Urban Forestry Commission hear a staff proposal and make recommendations to the City Council to consider. For amendments that relate to non-development situations, only the Urban Forestry Commission hears a staff proposal and makes a recommendation to the City Council.

Since this project relates to development situations, both Commissions will hear the staff proposal and make recommendations to the City Council.

Likewise, for this project, most of the amendments affect private trees in development situations, so BDS is leading the update project, while working closely with both PP&R-Urban Forestry and BPS, as directed by the City Council, to involve a broad range of expertise.
 

Portland’s Tree Canopy

Does the City of Portland have a goal for canopy coverage?
Yes, the 2004 PP&R Urban Forestry Management Plan initially set a citywide canopy target of 33.3%, with specific canopy goals for different zones (15% within commercial and industrial zones). These canopy goals were formally adopted in the Portland Plan 2012, with a target date of achievement by 2035.

What is Portland’s current canopy coverage?
As of 2015, Portland’s urban forest covered 30.7% of the City. However, the distribution of tree canopy is not equitable. On the west side, canopy coverage is 53%, while just 21% on the east side. For comparison, Los Angeles has coverage of 25%.

Additionally, Portland’s tree canopy varies by land use type:

  • Industrial: 9.7% canopy coverage
  • Commercial: 13.3% canopy coverage
  • Open Space: 54.4% canopy coverage
  • Residential: 34% canopy coverage


Current Tree Code Updates

What is scope of the current update?
The current project to amend the City’s tree code (Title 11) is focused on two proposals:

  • Removal of exemptions from tree preservation and planting requirements for trees on private lands and city-owned and managed property in the relevant industrial or commercial zones. Here is a map of the areas that would be affected by this amendment.
  • Reduction of tree size threshold for required tree preservation, from 36 inches diameter at breast height (dbh) to 20 inches dbh, during development on private property. If trees of this size are not preserved, a fee in lieu of preservation would be calculated based on the diameter inches of the tree. Currently trees under 36 inches dbh are assessed a flat rate fee in lieu of preservation. Reducing the size threshold would work to strengthen tree preservation of trees 20 inches dbh and greater. This amendment would apply in all areas of the city when tree preservation is required.


Are street trees addressed as part of this project?
Street trees are not part of the current tree code amendment project.

Are trees on City-owned or managed sites affected by this project?
There are a few City-owned or managed properties within the IH, IG1, CX and EX zones. Being within these zones, these properties are currently exempt from tree preservation requirements and tree density requirements in Chapter 11.50. Any changes to tree preservation requirements from the proposed amendments would apply to these city-owned and managed properties as well.

Reducing the size threshold from 36 inches dbh to 20 inches dbh only affects trees on private property, so trees on City-owned or managed property would not be affected. It should be noted that when development occurs on City-owned or managed sites, applicants are required to consult with the City Forester at the preliminary design phase, if trees are proposed for removal. The purpose of this consultation is to identify opportunities to retain trees as an alternative to removal.

Will there be a more complete update to the tree code later?  When and how will that happen?
The City Council Resolution in January 2020, which directed City bureaus to work on this current amendment project, also directed PP&R to consider a broader review of Title 11. PP&R will return by December 2020 with a proposed scope of work for the additional code amendments. A formal call for public input will be announced later this summer. In the meantime, if you have ideas for tree code improvement, please email: nik.desai@portlandoregon.gov.

Purpose of Tree Code

What is the purpose of Title 11, Tree Code?
The Tree Code supports and implements the forest infrastructure goals of the City of Portland’s Urban Forest Management Plan. “[The code] regulates the removal, protection and planting of trees through the development process to encourage development, where practicable, to incorporate existing trees, particularly high quality or larger trees and groves, into the site design, to retain sufficient space to plant new trees, and to ensure suitable tree replacement when trees are removed. It is the intent of these provisions to lessen the impact of tree removal and to ensure mitigation when tree preservation standards are not met.”
 

How is the Tree Code organized?
The City’s Tree Code is broadly divided between non-development and development activities, as well as between trees on private property, trees on City property, and street trees in the public right-of-way. For private trees in development situations, the basic requirement is that one-third of trees 12 inches DBH (diameter at breast height, measured 4.5 feet above ground) or larger must be preserved or a fee paid in lieu of preservation. All trees that are 36 inches DBH or greater must be preserved or a fee paid in lieu of preservation. That fee is based on the size of the tree and is higher than it is for trees less than 36 inch DBH. For more information on Tree Code requirements, visit www.portlandoregon.gov/trees. You can also read the Tree Code here.
 

What amendments were initially proposed to Portland’s Tree Code?
In December 2019, the Portland City Council extended to the end of 2024 the current rules for tree preservation of larger-diameter trees when development occurs. These rules require that trees 36 inches in diameter or more must be preserved or a larger mitigation fee (currently $450 per diameter-inch) be assessed if they are removed. When this extension was being considered the Urban Forestry Commission (UFC) and the Planning and Sustainability Commission (PSC) recommended removing existing exemptions to tree preservation and tree density (planting) requirements in some commercial and industrial zones. The UFC also recommended reducing the threshold for the inch-for-inch mitigation fee from 36 inches to 20 inches DBH.  In response, City Council directed the Bureaus of Development Services (BDS), Parks and Recreation (PP&R), and Planning and Sustainability (BPS) to conduct data analysis, legal review, and stakeholder engagement to develop proposals to address these recommended amendments to the Tree Code.
 

How are the mitigation fees spent?
Revenue from mitigation fees is placed in the Tree Planting and Preservation Fund (TPPF) administered by the Urban Forestry Division of Portland Parks and Recreation. Fees are used to plant trees or purchase property where tree canopy is needed most, as detailed in the Citywide tree planting strategy called “Growing a More Equitable Forest.” PP&R Urban Forestry reports annually to City Council on the use of the funds.
 

What analysis is being conducted?
Before removing exemptions to tree preservation and tree density requirements in four industrial, employment and commercial zones, the City of Portland must ensure continued compliance with relevant state land use planning goals. One requirement is to maintain a supply of land for industrial development, job growth, and corresponding economic opportunities. The analysis includes:

Tree Canopy Analysis: To evaluate the likely impacts of the application of new requirements in the currently-exempted zones, estimates of the trees on typical sites were generated. For exempt industrial zones (IH and IG1), GIS tools and site visits were used to estimate the number of trees per canopy acre. For the two commercial and employment zones (CX and EX), and all other zones, staff reviewed tree plans in permits from the last two years to estimate typical tree canopy composition. The outcomes of the staff permit review were also used to estimate the number of additional trees that would now be subject to the inch-for-inch mitigation fee in the various land use types.

Economic Analysis: With tree canopy estimates developed, each proposed amendment was analyzed to determine the likely increase in costs and associated reduction in expected development capacity. The economic impact of removing the tree preservation and tree density (planting) exemptions for the four industrial, employment and commercial zones was estimated. Reducing the size threshold for tree preservation on private property required estimating the impacts of the lower threshold on the cost of private property development in all zones. The results of the staff permit review were also used to estimate the number of trees that would now be subject to the inch-for-inch mitigation fee in the various land use types.

Staff Analysis:In addition to the outcomes of the tree canopy and economic analyses, staff also considered the ecological, community, and health benefits of additional tree preservation and mitigation, community perspectives, and the equity implications of this project.
 

Why are trees important?
Trees are essential infrastructure in the city and provide a multitude of well-researched and well-established environmental and public health services, including mitigating effects of climate change. Urban trees have been shown to:

  • absorb greenhouse gases
  • improve air quality
  • reduce urban heat island effect
  • store and sequester carbon
  • reduce stormwater runoff and sewage overflow into rivers and streams
  • reduce infrastructure maintenance costs
  • provide habitat for birds and pollinators
  • slow vehicle speeds, improving pedestrian and vehicle safety
  • reduce illness and disease rates and improve mental and physical health
  • reduce building heating and cooling costs
  • improve academic performance of students

What are the equity implications for the proposed Tree Code amendments?
Canopy disparities: Portland's tree canopy is not distributed evenly throughout the city. Significant variation exists in canopy cover among individual neighborhoods. West of the Willamette River, canopy cover is 56 percent. East of the Willamette River, where 80 percent of Portland’s residents live, canopy cover is only 21 percent. Tree canopy tends to be low, and the prevalence and intensity of urban heat islands are higher near areas where higher percentages of people of color and those with limited English language proficiency live. Additionally, economically-vulnerable populations often live near industrial zones. Given the benefits of trees and tree canopy, it is important to increase them in areas where they are needed most.

Income disparities: Where job growth occurs contributes to the Portland region’s racial inequities, including regional income inequality, poverty (lack of income self-sufficiency), and income-related health impacts. Income disparities are an often-cited example of the region’s broad range of racial inequities. Major contributing factors in these racial income disparities are the region’s increasing wage inequality (minimal growth in middle-wage occupations) and the racial profile of occupation types. Though retail, office, and non-industrial jobs also provide employment opportunities, among middle- and high-wage occupations, industrial jobs stand out as the only major occupations in the Portland region that hire proportionally more workers of color. Providing for adequate employment opportunities in this sector is one important strategy to reducing racial income disparities. The supply and cost of housing city-wide are also important considerations.
 

How have stakeholders been involved?
The project team is conducting a multi-faceted program for stakeholder input and public engagement. Interviews were conducted with 27 stakeholders and community members representing a variety of organizations including environmental advocacy, identity groups, neighborhood, and business groups. A survey posted online for broader public feedback received more than 2,000 responses. Workshops initially planned to gather feedback on the proposal were moved to an online platform in the wake of COVID-19. Further opportunities for input on the final Tree Code proposals will occur through upcoming meetings and hearings of the Urban Forestry Commission, Planning and Sustainability Commission, and Portland City Council.
 

If exemptions from tree preservation and tree density continue in the IH zone, will there be another opportunity to evaluate removing them?
Yes. The Bureau of Planning and Sustainability is beginning a five-year update to the City’s Economic Opportunities Analysis as required by the State of Oregon. This analysis provides an opening to evaluate removing or modifying the exemptions, if mitigating strategies can be developed through other means to balance out the impact on job growth. In addition, a scope for a more comprehensive review and updating of the Tree Code is expected to be brought to City Council for their review at the end of 2020. If that project moves forward, it may consider updates to the way in which the IH zone and other zones are addressed. Any proposed changes could be informed by the outcomes of the Economic Opportunities Analysis update.

Tree Canopy Analysis

The City contracted with SWCA, an environmental consultant, to conduct tree size composition analyses in industrial zones.

What tree data was used for the analysis?
Using the most recent LIDAR dataset, the consultant estimated tree counts in four diameter classes based on tree crown characteristics. Existing PP&R tree inventories and site visits were used to calibrate the tree canopy model. Tree size composition data for commercial, single-family, and multi-family development was estimated by reviewing 1,000 development permits issued over a two-year period to determine presence of trees in different size classes.
 

Why are tree canopy percentages in the economic analysis higher than in other published data?
The analysis focused only on new areas that would be subject to the proposed Tree Code amendments. More specifically, the analysis included only private tax lots and portions of those lots not currently regulated by other tree requirements, such as an environmental overlay zone. Additionally, the analysis focused on properties in the City’s buildable lands inventory (BLI), which consists of vacant properties and those likely to be redeveloped within 20 years. Vacant properties would be expected to have more tree canopy than comparable developed ones, increasing the estimated tree canopy percentages. Focusing the analysis on those sites specifically affected helped to determine the added impact of the new requirements.
 

Are dead–dying–dangerous–and nuisance trees accounted for in the study?
Yes. Trees in these categories are exempt from tree preservation requirements, so it is important to exclude them from the tree canopy analysis that informed the economic analysis. Estimates for these variables were based on statistics from Portland’s Street Tree Inventory for trees in dead or poor condition, as well as nuisance tree data from the U.S. Forest Service Urban Forest Inventory & Analysis (UFIA) for Portland.

For industrial areas, it was estimated that 15 percent of trees are dead, dying, dangerous or nuisance trees. For all other areas, it was estimated that 10 percent of trees would fall into this category. In industrial areas it is expected that there will be less ongoing tree maintenance, which accounts for the higher estimated percentage of dead and poor trees in these areas.

Economic Analysis

The City contracted with Johnson Economics to analyze the impact of the proposed tree regulations on development.


How did the economic analysis calculate impacts on development?
The analysis looked at the added cost of development over a 20-year timeframe if the exemptions from tree preservation and tree density (planting) were removed in the Heavy Industrial (IH), General Industrial 1 (IG1), Central Commercial (CX), and Central Employment (EX) zones. The analysis also looked at the added cost of development over the same timeframe if the threshold for required tree preservation and payment of an inch-for-inch mitigation fee, was reduced from a diameter of 36-inches or greater to 20-inches. Additional costs and land development impacts were estimated based on the mitigation fee required to be paid in-lieu of preservation or planting. If the additional cost to comply with the new tree preservation and planting requirements and the reduced tree preservation size threshold would increase the cost of development beyond the market’s ability to absorb those costs, these areas would then be removed from the acreage available for projected job growth over a 20-year timeframe.

What did the economic analysis conclude?
Development In the General Industrial 1 (IG1), Central Commercial (CX), and Central Employment (EX) zones: For General Industrial 1 (IG1), Central Commercial (CX), and Central Employment (EX) zones, the removal of the exemption would not result in a loss that would compromise the City’s ability to accommodate the projected 20-year development demand.

Development in the Heavy Industrial(IH) Zone: Employment impacts would result from the Tree Code changes in Portland’s Harbor Access Lands and Harbor and Airport District subareas because of their low, freight-oriented density. In the Heavy Industrial (IH) zone in these districts, the impact of the removal of the tree preservation and tree density exemption, as well as changes in the tree preservation threshold, would decrease the projected development acreage to less than is needed, based on the 20-year demand estimated in the current Economic Opportunities Analysis. Specifically, eliminating the tree preservation exemption in IH zone would reduce the available land by 11.8 acres; eliminating the tree density exemption in the IH zone would reduce the available land by an additional 11.9 acres. There are currently 10 acres of surplus land for employment in these industrial districts.

Job Growth in the Heavy Industrial (IH) Zone: Job Growth: Removal of the tree preservation and tree density exemptions in the IH zone is estimated to reduce employment growth there by 830 jobs over 20 years; changes to the tree preservation threshold to 20-inch diameter trees are estimated to reduce 20-year employment growth by another 300 jobs in these freight-hub industrial subareas.

Housing Development: Housing construction costs are estimated to increase by 0.11 percent, resulting in a loss of 54 residential units over 20 years.