Just a couple miles west of Sherwood, Baker Creek winds from south to north for four miles through ravines topped with farms, ranches, homes and forests. Its waters eventually flow into the Tualatin River. Metro manages four natural areas along the creek that add up to more than 300 acres.
When you first looked at this photo of Baker Creek, you probably thought something like, “Wow, that’s really pretty.” Maybe you spotted a tree species or two you recognize; possibly, you imagined the animals that live there. Maybe you spied the pond and looked for a beaver dam. If you looked at it long enough, you probably started getting a feeling that there was so much more you weren’t seeing. There are mysteries in the photo.
Some people can see into many of those mysteries (usually they find even more there).
It takes years, but if you’ve studied something deeply you’re able to look at it with almost superhero vision. You see details most people overlook, make connections unknown to others, you even know the structures hidden behind the surface that make the whole thing work. It works for a mechanic looking at a car, a musician hearing a song, a gamer playing a game. It happens when Andrea Berkley, one of Metro natural resource scientists, looks at a forest.
Andrea experiences the photo those ways, too. In her role overseeing restoration at Baker Creek with partners from Clean Water Services, she also sees where invasive plants are crowding out native species. She sees how the forest is reforming after being logged. She sees strengths in the habitat and what might help make those even stronger.
Let’s take a look at what Andrea sees after she says, “Wow, that’s really pretty.”
1. Forest health
Hillsides along Baker Creek have been logged in the past, and now support a young forest with a mix of evergreen and deciduous trees that are 20 to 40 years old. The plant communities are recovering from this past disturbance slowly but surely, with a lovely forest-floor wildflower display in the spring. Some areas are overcrowded with trees, especially Douglas fir and bigleaf maple, which grow in quickly after timber harvests. Many of these trees won’t survive the dense conditions, and slower-growing species won’t ever get a chance. Metro will thin these stands, letting more species grow into larger, healthier trees.
2. Big leaf maples
There are many bigleaf maples along Baker Creek that were cut down, but survived, when Douglas fir were harvested decades ago. Those maples sent out lots of new shoots, which now have formed trees with multiple, large trunks coming out of one root mass. These root sprouts now spell doom for these trees – as these trunks get larger and heavier, these maples will break open like a blooming onion at Outback Steakhouse. To preserve these trees, we will thin the trees, leaving the healthiest trunks behind to grow into robust, large maple trees.
3. Beaver-built wetlands
Throughout Baker Creek you’ll stumble upon beaver dams, old and new. Older dams have trees and shrubs growing on them; newer dams have freshly harvested sticks and mud. Beaver dams provide tremendous environmental benefits by creating wetlands, often called “biological super systems” because of the rich biodiversity contained within them. These wetlands boost fish and wildlife numbers, but they also buffer the watershed from the effects of drought by saturating the soil and recharging groundwater aquifers. And by slowing down the water coming down a creek, they reduce the rate of soil erosion which keeps the water cleaner.
4. Fish passage
The Tualatin River and the streams that feed into it support many native fish species, including winter steelhead, coho salmon and cutthroat trout. Although Baker Creek does support many native fish species, searches for salmon up to Mountain Creek Road have come up empty. Metro and Clean Water Services are working together to find and modify or remove barriers like culverts or small dams that block salmon migrating up and downstream. In 2022 Metro and Clean Water Services will remove a small dam in one of the natural areas along Baker Creek. Small dams can create high water temperatures and lower dissolved oxygen levels, both being bad news for animals living in the stream.
5. Stream channel shape
Baker Creek and other streams like it have undergone many changes as people have worked the landscape. Tree removal, introduction of invasive species and development along the creek corridor all cause rainfall to move down the creek faster. All this fast water erodes the soil along the edges and the bottom of the stream, making the water murky, and gradually changing the stream from a winding shape to a straighter channel that rarely spreads to the floodplain. The floodplain area is rich habitat where all sorts of creatures and plants live, including juvenile salmon looking for tasty bugs to eat to fatten up during floods. Along Baker Creek channel straightening and erosion have been slowed by the nighttime work of beavers.
6. Reed canary grass
Reed canarygrass is one of the most successful invasive aquatic plants in the Pacific Northwest. It spreads by seeds and rhizomes, creeping underground stems that produce plants far from the parent. This grass starts its growing season before many native plants, which means it crowds them out before they even start growing. These dense stands have little wildlife or insect habitat value and disrupt food chains in wetlands and along streams. Clean Water Services treats the canarygrass, then quickly plants at least 3,000 native sedges, rushes, grasses, shrubs and trees per acre. These plants will eventually outcompete the weedy grass.
7. Nature knows no borders
The yellow plants are Scotch broom, a prolific invasive bush that you’ve probably seen on the side of highways. These plants are growing on a property next to the natural area. Unfortunately, weeds don’t care about property lines. The best thing we can do to keep the Scotch broom out is look for it periodically and remove it and ensure diverse groups of native plants thrive so there’s no room for invasive weeds.