Assessing our trees
No matter if temperatures surged above 100 degrees or if rain soaked the city, Josh Seekatz and Andrew Sheehan could be spotted meandering Wilsonville streets, staring intently at trees and jotting down notes.
Starting in July and finishing just before Christmas, the two Public Works Department interns spent much of their workdays surveying over 24,000 street trees — 274 species in all. They then compiled the data and delivered a comprehensive presentation to Wilsonville City Council during a January work session.
During the project, the duo recorded trees' species, genera and families as well as their height and trunk diameter and jotted down any damages to city utilities caused by trees. They also distilled neighborhood-specific data.
The interns found that 88 percent of the trees in Wilsonville are healthy while 9 percent are stressed and 1 percent are dead. Also, they found 1,139 instances of sidewalk damage and 3,604 instances of utility conflicts caused by street trees. Examples of street tree damage include trees that cover storm drainage and cause curbs to crack or lift.
Only 75 percent of the trees in Villebois are healthy while 19 percent are stressed; 80 percent of trees are healthy and 16 percent are stressed in Wilsonville's town center, and 98 percent of trees are healthy in Charbonneau.
Other trivia included in the study: red maples are the most prevalent trees; 32 percent of Douglas firs are over 90 feet tall; soapberrys are the most common tree family; maples are the most common genera; there are about 40 palm trees in Wilsonville; there's a single sycamore tree above 90 feet tall; the tallest tree is 160 feet; 45 percent of trees are less than 20 feet tall while about 1 percent rise above 100 feet.
And the iTrees application created by the United States Forest Service calculated that $622,148 in energy, carbon, air quality and stormwater benefits are the product of street trees in Wilsonville.
"You input the tree data —the species, diameter and height — and things like that and then they have formulas built into the program that analyze that and then provide benefits for the trees based off that information," Sheehan said.
They did not analyze yard trees or trees in natural areas and say the benefits of those trees are likely much greater than the street trees.
"Realistically our urban canopy is providing two to ten times the number of benefits including natural areas and parks," Seekatz said.
Public Works Director Delora Kerber said the City of Wilsonville is undergoing an assessment of city assets and the tree survey is a part of that process.
Councilor Charlotte Lehan says the City hopes to use the data to plant trees in the right places and to refrain from planting problematic trees.
"It would give us a certain amount of data that this tree is continuing to be a problem for these reasons or this neighborhood had the wrong tree planted," councilor Charlotte Lehan said.
Wilsonville City Manager Bryan Cosgrove added: "If we deem a street tree as problematic we could put it on our 'do not plant' list."
After the presentation, Wilsonville personnel praised Seekatz and Sheehan for their hard work.
"This is great data for us and the program; the internship program is going to be extremely valuable and provides good work experience. We appreciate the good work," Cosgrove said.
Seekatz and Sheehan converged from dissimilar backgrounds.
Seekatz studied botany at University of Puget Sound and worked on habitat restoration while Sheehan has a geographic information system expertise and worked for Clackamas County and TriMet before earning the internship. Before the project, the interns didn't have extensive knowledge about trees and so had to study them before diving into the data collection phase.
"I think it's been a great learning experience. I didn't have much experience with tree identification because that wasn't my background but I learned a lot doing this project," Sheehan said.
After they finish the internship in the next month, Seekatz hopes to focus on ecological conservation and would like to conduct similar surveys while Sheehan would like to continue working with municipal governments.
Whether they're driving around town or walking through a forest, from now on, they will have considerable knowledge to inundate companions with tree-related information.
"I'm pretty annoying on hikes," Seekatz said.