PP&R study shows Portland's urban forest is in decline since 2015

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Findings show first tree canopy decline since 2000; tree preservation and planting efforts remain top City priority.
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(Portland, OR)-

Portland’s tree canopy has declined since 2015, according to the recently released Tree Canopy Monitoring Report from Portland Parks & Recreation (PP&R)’s Urban Forestry team.

The report, being presented to City Council on March 16, 2022, found that tree canopy in Portland area has decreased from 30.7% in 2015 to 29.8% in 2020. That’s equal to losing an area the size of Mt. Tabor Park every year during that time period.

Sunlight filters through the canopy of gorgeous trees in PP&R's Columbia Park.
Sunlight filters through the canopy of a grove of gorgeous trees in PP&R's Columbia Park.

All zoning areas—including commercial, industrial, open space and residential—recorded tree canopy loss, amounting to 823 total acres. The most notable loss occurred in residential zone, with tree canopy loss of 523 acres. PP&R followed US Forest Service methodology to track the amount of Portland tree canopy cover in 2000, 2005, 2010, 2015, and 2020. Future updates of this study will show whether losses found during this period continues, but these losses occurred despite greater tree protections put in place since 2015.

In response, PP&R and Parks Commissioner Carmen Rubio urge the City to take immediate action to protect, replace, and equitably grow Portland’s urban forest.

“This important, thorough scientific study is a wake-up call for us,” says Commissioner Rubio. “Trees strengthen our resilience to climate change, but they are also vulnerable to climate-change-fueled weather. We need to take concrete actions to replace the trees we’re losing and create an equitable tree canopy that will bolster our resilience to climate change. Next month, I will ask City Council to consider a resolution directing action to do this.”

Portland’s urban forest is not only beautiful and functional but also provides physical, mental, emotional, and psychological benefits to neighbors. Trees everywhere also play an important role in climate change mitigation and adaptation. They also can support urban climate adaptation through heat reduction and improved air quality, which have direct human health implications.

PP&R Director Adena Long reiterates the need for clear policy direction to address tree canopy loss in the reported period.

“PP&R will continue to care for and maintain Portland’s trees, to address hazards on City lands and public streets, and to plant more trees citywide,” says Long. “This report shows the need for continued efforts and vigilance. I’m pleased that the 2020 Parks Local Option Levy will, at last, allow the City to do proactive maintenance on some trees in parks and natural areas.”

Portland’s Urban Forest Management Plan recommends targets of 35-40% tree canopy cover for the residential urban land environment (ULE), and 15% for the commercial, industrial, and institutional ULE. PP&R’s Canopy Report in 2007 and the City of Portland’s Climate Action Plan (2009 and 2015) set a goal of expanding urban forest canopy to cover one-third of the city’s area.

The 2020 Tree Canopy Monitoring report provides baseline data that can be used to establish and refine canopy targets. Portland’s Urban Forest Management Plan is scheduled to be updated in coming years, providing an opportunity for revising tree canopy goals, using new information on areas of potential growth to set realistic targets.

“Well-developed tree canopy targets provide the opportunity to make deliberate and clear decisions for planning and goal setting for the future of the urban forest,” said City Forester Jenn Cairo. “We’re continuing Portland Parks & Recreation’s important work to improve tree preservation and increase tree planting. Further work on the findings of the report will be carried out independently by Metro staff and researchers from Portland State University.”

With the passage of the Parks Local Option Levy (Parks Levy), PP&R will be able to better protect Portland’s 1.2 million park trees by performing proactive maintenance, safety checks, hazard removal, and planting new trees in parks and natural areas. Through the City’s Fall Budget Monitoring Process (BMP), City Council approved the addition of 23 full-time employees for PP&R’s Urban Forestry team. The bureau is currently recruiting for these positions that will help create a proactive tree maintenance program and begin working to help trees in parks and natural areas get the care they need to continue benefiting our community. This is a citywide effort, not limited to any one part of town.

PP&R’s report can be found at portland.gov/sites/default/files/2022/tree-canopy-monitoring-2020.pdf.

Additional Background

The Tree Canopy Monitoring: Protocol and Monitoring from 2000-2020 Report is produced by Portland Parks & Recreation to measure the city’s urban forest health. This report is updated regularly, and the next measurement will be taken in 2025.

Tree canopy cover is identified as an important measure of environmental health by the City of Portland. The amount of tree canopy cover is a measure of Portland Parks & Recreation bureau-wide performance and is also cited as an important indicator in the Portland’s Urban Forest Management Plan (2004), Urban Forest Action Plan (2007), Climate Action Plan (2015), and t 2035 Comprehensive Plan (2016).  Monitoring Portland’s tree canopy is important to understand how canopy coverage may be changing. Understanding these trends informs important decisions regarding management strategies.

The findings note that due to the short time period in question, losses found between 2015-2020 are within the margin of error. Additionally, important questions, including the causes of tree loss, and what areas of the city are most impacted, are not addressed in the report.

About Portland Parks & Recreation UrbanForestry

The mission of PP&R’s Urban Forestry (UF) division is to manage and care for Portland's tree infrastructure for current and future generations. Portland’s urban forest consists of 220,000 street trees, 1.2 million park trees, and nearly three million private property trees. The Urban Forestry division is involved in managing or regulating these trees.

UF led creation and implements the City of Portland's Urban Forest Management Plan, fosters community tree awareness and stewardship, and develops tree policies and programs. The department monitors and assesses Portland’s urban forest and implements City regulations including issuing permits for planting, pruning, and removal of public and some private trees. During extreme weather at all times of the year, UF crews respond to tree emergencies to keep you safe and the City moving. Portland is aTree City USAfor 44 years, aTree City of the Worldand the Urban Forestry program is accreditedby the Society of Municipal Arborists. To learn more about Urban Forestry’s work, please visit portland.gov/trees/about-urban-forestry