By Neva Knott
Restoring urban watersheds is an important part of developing a city’s green infrastructure. These streams and surrounding landscapes comprise an important ecosystem for wildlife and humans. Urban watersheds are habitat for fish, animals small and large, birds and plants. They also provide important ecosystems services, like filtering rain and groundwater and capturing carbon and other air pollutants. Urban watersheds are landscapes that connect people to nature within the business of city life.
Last Saturday, I donned rubber boots and rain gear and headed out to the Lower Powell Butte Floodplain along Johnson Creek, part of the Johnson Creek Watershed in Portland, Oregon, to lead crews of volunteers for Friends of Trees in planting several species of native trees and shrubs to restore a section of the creek bank.
Project History, provided by Friends of Trees: “In partnership with the Johnson Creek Watershed Council and Portland Parks & Recreation we will be planting native trees and shrubs to improve the creek side native plant community. This project is supported by the East Multnomah Soil & Water Conservation District and Metro. PP & R has been working for a number of years to treat invasive species in the area, primarily Reed Canary Grass, to prepare the site for replanting. This planting will be the second at the site and will expand upon the area planted by Friends of Trees in 2014. FOT has performed summer maintenance and monitoring for the past two seasons to keep invasive species down and help previously planted natives become established. The native trees and shrubs planted here will provide greater wildlife habitat, increase native plant diversity, and enhance water quality by filtering pollutants and assisting with erosion control along Johnson Creek.”
On Saturday, the FOT crew and volunteers planted 690 native trees and shrubs–Black Hawthorne, Oregon Ash, Black Twinberry, Pacific Ninebark, Thimbleberry, Swamp Rose, and Snowberry. These species are often used in stream bed restoration because they tolerate wet-to-dry conditions.
My team was in charge of getting the Black Twinberries into the ground. We planted starts–each plant was just about four inches tall, dormant with no leaves or fruit yet, but with vibrant root systems. Thimbleberries grow rapidly though, and form dense thickets up to seven feet tall. The mature shrubs function as habitat in that they provide food for many types of animals, cover from predation for small species, and regulate ground, stream, and air temperature. When our thimbleberries mature, they will bring wildlife to the area–to include several bird species, rabbits, beavers, deer, coyote–helping to create a once-again functioning ecosystem along Johnson Creek.
Teaching volunteers to plant trees is something I enjoy and value because it allows me to help people interact in a very intimate way with the ecosystems we depend on. This past Saturday, I had several seven- to nine-year-old scouts on my team. Planting with children is extra fun; they are so simply in awe of the effects of their own efforts. And, they love finding worms.
Working with Friends of Trees not only allows me to help others connect to nature, understand ecosystems, and find worms, it allows me to learn more about plant species. I am intrigued by ethnobotany–the study of the relationships between plants and people. This cultural value of native plants is another important reason for using them, and is an aspect of plants that can connect the past to the present. A source I regularly look to is The Wild Garden: Hansen’s Northwest Native Plant Database, where I found that First Nations groups harvested thimbleberries for a variety of uses:
- The leaves were mixed with those of wild strawberry and wild trailing blackberry to make tea
- The sprouts were collected, peeled, and eaten raw as a vegetable
- Berries were eaten fresh and dried, sometimes with the addition of clams and pressed into cakes, for winter use
- While still pink, they were harvested by some tribes and placed in cedar bark bags, water was sprinkled on top and they would ripen in the bag
- The leaves were also used as padding to line baskets
- The boiled bark was an ingredient in soap
- Dried, crushed leaves were laid on burns to prevent scarring
Native plants are most of the choice in restoration work. They allow for a sense of place and let flourish the botanical uniqueness of the region. They attract and feed native insects, birds, and wildlife. Their genetic design allows them to flourish with other native species in the same environment and in that particular set of conditions. And, native plants require fewer inputs–fertilizers and extra water–because they are attuned to the soil and weather of the region.
One of the goals of the restoration work along Johnson Creek is to improve water quality for the salmon who navigate through the watershed to breed and spawn.
Johnson Creek is unique in that it is the only salmon-bearing stream in the city. This is significant because salmon are a keystone species in the Pacific Northwest, supporting 137 other species. The viability of salmon is an indicator of watershed quality and health. Salmon also holds high cultural value in the region because it is a traditional ceremonial food of the Native tribes and has long been an emblem of Pacific Northwest culture and cuisine. Salmon definitely is a food that connects past to present and it is a fish species that pulls together the peoples of the region across ecological, economic, and cultural boundaries. A regional ecological concern is water quality for salmon.
The ecosystem services watersheds like Johnson Creek provide serve wildlife and humans; more importantly, watersheds connect nature and humans and remind us that much can be gained by looking to nature for solutions to particular problems of urban (and non-urban) environments. Whereas technological structures, such as sewer pipes underground in a city, serve as solutions to many environmental problems, plants can provide cheaper and more readily usable solutions. Green infrastructure is forward-thinking, often more effective, and always less costly that man-made infrastructure.
There’s a lovely walking and bike path along the creek and our planting area, next time you need a break from hectic city life. And, the thimbleberries ripen in late July.
- Map of Johnson Creek Watershed: US Geological Survey
- Thimbleberries: The Wild Garden
- Salmon in Stream: US Fish and Wildlife
- All other photographs by Neva Knott