The figure is set to ensure that trees are equitably distributed across the city 

COURTESY PHOTO - The city of Wilsonville wants to boost the town's tree canopy by 6% in the next 25 years.

The city of Wilsonville aspires to add 27,000 trees — thus increasing the overall population by 6% — to its tree canopy by 2046. At least that is what's stated in a draft of its Urban Forest Management Plan.

The goal is to ensure that all areas of Wilsonville have a tree canopy score of 75 out of 100 or higher, based on a tree equity tool produced by the nonprofit conservation organization American Forests. The American Forests' tool centers on the idea that trees are more plentiful in affluent areas and less so in poorer ones.

"With the knowledge the score provides, Wilsonville's community leaders, tree advocates, and residents alike can address climate change and public health through the lens of social equity, attract new resources, factor the scores into technical decisions, guide implementation of the Urban Forest Management Plan, and track progress toward achieving tree equity. A score of 100 represents tree equity," the plan read.

The areas of Wilsonville with the highest current tree scores are located in Charbonneau and sections east of I-5 near Memorial Park. The areas with the lowest scores mostly reside in north Wilsonville. In its plan, the city emphasized the benefits that a larger tree canopy could have on the community.

"Based on the Tree Equity Score tool, it is estimated these new trees will bring an added annual ecosystem service value of $350,633 once fully implemented. Planting trees that grow to large-canopied specimens at maturity and are healthy will sequester over 360 tons of carbon, 0.3 tons of carbon monoxide, 0.3 tons of sulfur dioxide, and 5.9 tons of ozone annually — all pollutants contributing to the greenhouse gas effect and changing climate," the plan read. "In addition, the 27,000 trees will reduce particulate matter by 1.7 tons (PM10) and 0.4 tons (PM2.5) annually and prevent the runoff of 15,117,774 gallons of stormwater each year."

Some ways listed to achieve this goal include planting new trees, educating private landowners about their responsibilities — both legal and values-driven — to take care of trees, removing invasive plants, allocating more funding for tree maintenance and continuing to perform forest assessments like the recent street tree inventory.

Currently, 30% of Wilsonville is covered by tree canopy.

The city also plans to examine the Charbonneau community and Town Center commercial area more thoroughly due to issues the city has had maintaining the red oak population in Charbonneau, and because of redevelopment plans in Town Center.

During a Wilsonville Planning Commission meeting Wednesday, Oct. 13, Natural Resources Manager Kerry Rappold said the city isn't going to conduct tree planting efforts based solely on the equity tool. He added that the city will need to conduct a more granular analysis to determine which areas should be designated for planting. The city also plans to establish a working group that would monitor the tree canopy and the progress of implementing the plan.

"We know we need to do some refinement to this. It (the tool) gave us an opportunity to do a little bit of benchmarking and something that's comparative across the nation in some way. It's viewed as a starting point," he said at the meeting.

A key to the plan, according to city staff and consultants, is education. Because much of the tree canopy is located on private land and the city's regulations can only do so much, it will be largely up to private landowners to fortify the tree habitat. The city is considering producing a manual to help owners maintain their trees and follow city code. Trees that are at least six inches in diameter require a permit for removal and some trees have further protections based on city code.

"(The manual would) provide greater clarification in terms of their responsibilities and what they can do to build a healthier tree population," Rappold said.

In an interview, Rappold said the recent winter storm, which led to a sizable reduction in the city's street trees, will mean the city has some catch-up work to do in terms of boosting the overall canopy.

The natural resources manager added that the city is planning to wrap up the forest management plan by the end of the year.

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