Former Corvallis City Forester Joins Statewide OSU Urban Forestry Effort

The quality and presence of trees in a city can significantly affect how people feel about the city.

But trees in urban environments face pressures that can hinder their growth and limit their life span, such as restrained growing space, compacted or poor-quality soil and pollution.

It’s the goal of the urban forester to address these challenges and others while acting as tree advocates, scientists, planners and educators. That’s why Oregon State University Extension Service has two new urban foresters who are dedicated to enhancing urban forest health, resilience and community engagement throughout Oregon.

Jennifer Killian, who had once served as Corvallis’s urban forester,  and Sarah Low are both assistant professors of practice in the College of Forestry who will share responsibilities for urban forestry Extension and urban forestry online teaching.

Holly Ober, associate dean for science and outreach in the College of Forestry and program leader for OSU Extension’s Forestry and Natural Resources program, said the positions add to the program’s strengths in addressing the needs of woodland owners, natural resource professionals and youth educators.

“Over time we’ve been hearing more and more questions and concerns about trees and green spaces in urban and suburban regions that we weren’t well-prepared to address,” Ober said. “It became increasingly apparent that expertise in urban forestry could be a real boon to our overall team.”

‘Vital urban forests’

Killian comes to OSU with 16 years of experience in managing trees in an urban environment, including the City of Corvallis, the Oregon Department of Forestry and the nonprofit Friends of Trees in Eugene, spanning municipal, nonprofit and state forestry sectors.

She earned a bachelor’s degree in environmental studies at Edgewood University in Madison, Wisconsin, and a master’s degree in environmental sciences from Oregon State.

Killian describes the urban forest as “the trees where we work, live and play.”

She said her interest in urban forestry was sparked in her first job after college with the Wisconsin Department of Agriculture. She was on the team crisscrossing the state in search of the emerald ash borer, an invasive beetle from Asia that has killed tens of millions of ash trees in North America by burrowing under bark and disrupting the trees’ nutrient flow.

“We were helping communities prepare for its arrival,” Killian said. “Every city I visited had a unique approach to managing its urban forest, and I became fascinated by the different strategies and challenges involved. I realized then how vital urban forests are — and how much they need advocates. That was the moment I knew I wanted to be one of those voices.

“That role opened my eyes to the critical and often overlooked work happening at the intersection of urban environments and forest health,” she said.

Unique Extension opportunity

Low has more than 20 years of experience in urban ecology and forestry, having worked in federal and local government, nonprofits, and the private sector.

“What’s exciting to me about this position is the role of Extension in an urban environment,” Low said. “There’s so much opportunity to be of service.”

Low earned bachelor’s and master’s degrees in fish and wildlife conservation from the University of Massachusetts Amherst, with a focus on watershed science and management. Low contributed to the establishment of the Philadelphia Urban Field Station while working at the U.S. Department of Agriculture Forest Service and later founded the Tacoma Tree Foundation.

All those years of experience have given Low a perspective of urban forestry.

“Urban forestry can be defined in different ways,” Low said. “I like to think of urban forestry as all the trees in an urban environment. The individual trees in a yard or right-a-way but also the fragments of forests and parks. In an urban environment you’ll see managed landscapes and infrastructure that create gaps that you won’t see in a natural forest.”

Needs assessment

Low and Killian have started planning a needs assessment of urban forestry in Oregon, using a preliminary assessment conducted by an OSU graduate student, a randomized survey of homeowners and renters, conversations with professionals throughout the state, as well as a large bank of Ask Extension questions.

“We’re navigating a lot of different topics as we think about our needs assessment and our program development,” Low said.

Foremost among them: destructive pests, heat and drought and the tension between development and preserving green spaces.

Emerald ash borer was detected in Washington County June 2022. The pest has spread to neighboring Clackamas, Yamhill and Marion counties. Another invader is the Mediterranean oak borer, which has infested Oregon white oak trees in the Portland metro area as well as Marion County.

These pests and others like them are “going to be a huge challenge not only to our urban street tree populations but our riparian stream populations,” Killian said.

As Oregon summers get drier and hotter, trees are succumbing to the elements.

“People are seeing that their trees are stressed,” Low said. “They’re worried about it and they’re coming to Extension for answers.”

Another issue is canopy cover: the layer of tree branches and leaves that provide shade and greenery. Wealthier neighborhoods often have much higher canopy cover than lower-income or historically marginalized communities, contributing to urban heat island effects, higher energy costs and health disparities in under-canopied neighborhoods.

“Development pressures are causing impacts to tree canopy,” Low said. “We want to embrace access to housing, but figuring out how to do that while maintaining canopy is going to be important.”

By Chris Branam