This story first appeared in the summer 2014 edition of Our Big Backyard magazine.
The Beaver Creek natural area near the Gresham-Troutdale border.
Admiring 10-foot tall Western red cedar trees along Beaver Creek, I felt a certain smugness. This natural area was moving quickly from a blackberry-dominated weed patch to a young forest – nudged along by Metro restoration projects and student volunteers at neighboring Mt. Hood Community College, near the Gresham-Troutdale border.
As a Metro natural resource scientist, Kate Holleran sees nature's biggest challenges and most glorious surprises – and she has the muddy boots to prove it. Go behind the scenes on her journey to restore the region’s voter-protected land.
When I returned a few days later with 20 students, the trees had been reduced to one-foot-tall stumps. An American beaver family had obviously arrived, found the table set and binged on every cedar tree we planted. That day was just one of many over the past seven years that have reminded me of a fundamental truth: if we set the table, wildlife will come and they will feast. Beaver, deer, elk and other animals benefit from the re-growth of native plants across our natural areas. Expecting wildlife and designing a restoration project that accommodates them is the key to success.
That memorable day at Beaver Creek, volunteers built beaver-exclusion fences around most of the stumpy cedars. The few remaining lower branches of the trees turned upward and took on the role of leaders. Four years later, the trees again tower well over my head. We will leave the fences up a little longer while we encourage a more diverse native plant menu to distract the beavers.
We have developed some creative ways to live compatibly with our native wildlife in our restoration areas. But non-native species are more challenging. One species that I will not welcome: the emerald ash borer, native to eastern Russia and Asia. Its name comes from the adult’s beguilingly beautiful iridescent green carapace. Because this non-native beetle feasts on ash trees, and only ash trees, a visit almost certainly means death. This phenomenon was first discovered in Michigan in 2002. With no effective way to control the problem on a large scale, millions of ash trees have been lost in the northeastern United States. The borer has moved as far west as Colorado, assisted by humans transporting firewood and other wood products. But not all beautiful, large green beetles are emerald ash borers, and Oregon is monitoring traps for the species that would so dramatically change our forests. None have been found – so far.
Though I am typically an optimist, I expect the emerald ash borer to arrive in Oregon during the next decade or so. I’m planning ahead at places like Beaver Creek, where we’ll increase the diversity of native trees and shrubs along more than half a mile of the creek. I’ll set the table by adding Columbia and Pacific willows, black cottonwood, and more Western red cedar and big leaf maple in slightly drier areas within the floodplain. I won’t plant Oregon ash, as it will naturally re-seed in small disturbed areas under the canopy.
The best science we have right now tells us that increasing species diversity is one of the best ways to create a resilient forest – one that may lose its Oregon ash, yet still protect our streams and provide habitat for our wildlife.