A recent article in the St. Helen's Chronicle:
By Caroline Skinner Friends of Nob Hill Nature Park
St. Helens is fortunate to still have many of its native white oak trees. These majestic trees are native to much of the West Coast, with a range from Vancouver Island, B.C., down to Los Angeles. While many oaks have been lost to development, there is now a renewed appreciation of not only their beauty, but also their importance in our ecosystem. Many communities are creating and preserving oak woodland habitat, including the new Baltimore Woods Park in the St. Johns neighborhood of Portland, as well as the Nob Hill Nature Park in St. Helens.
A recent program held by Friends of Baltimore Woods featured a speaker on native oak restoration and preservation. Mary Bushman, from Portland's Bureau of Environmental Services, shared information for Baltimore Woods that also applies to Nob Hill Nature Park.
Oregon's white oaks are the only oak trees native to the greater Portland area. We are in the middle of a corridor for migratory birds that use the oak habitat while traveling the range of their yearly migrations. The oaks provide food specific to some of these species, as well as resting places during their travel.
Oak woodland and savannah once covered 625 square miles of the Willamette Valley. That is more than half a million acres, including some wet areas. Little of that area remains now. Some of the large heritage oaks remaining indicate where other oaks used to live, showing how extensively they used to range. They can live for up to 500 years before starting to falter.
Typically, white oaks don't start producing acorns until at they are least 20 years old, dropping acorns from August to November. Trees growing from sprouts or re-growth grow faster than trees starting from acorns, since they can use the existing root system. As anyone who has seen them in Columbia County knows, they grow in dry, rocky hillsides but can also grow in flood plains.
Why restore Oregon white oak habitat?
Some of the native wildlife associated with oak and sheltered by it includes gray squirrel, western bluebird, white-breasted nuthatch, madrone, larkspur, biscuit root and aster. Invasive plants crowd out and suppress native plants. Also, some invasive species, like blackberry, are highly flammable. Oak has value in wildfire risk reduction. They do not create the large load of fuel found in Douglas fir forests.
For new native plants to succeed, invasive plants should first be under control.
Phase one for woodland restoration is intensive removal of invasive species. At Nob Hill Nature Park, the "friends of" group toiled for several years, starting with a SOLV trash removal event, followed by removal of ivy, holly and blackberries, with much help from their partner group, Scappoose Bay Watershed Council.
Phase two involves adding native plants, shrubs, trees and possibly grasses. At NHNP, overlooking the Columbia River, we've planted flowering red currant, vine maple, spirea, willow and Columbia lily, among others. Native plants, including several kinds of wild lilies, are starting to rebound after the removal of blackberry and ivy at the park. Spring plantings are more difficult to keep alive through summer's dry season, so fall planting is best when possible.
Phase three involves maintenance, including weed control, adding plants as needed, and follow-up watering. This phase should continue for at least three years for best results, according to Mary Bushman, who is leading the Baltimore Park project.
"Friends-of groups can be the eyes and ears of the area, and make long-term management possible," she said.
Also, holding volunteer work parties is a great way to continue to make progress, as well as to see and appreciate the changes. At Nob Hill Nature Park, work parties take place twice yearly, on the first Saturday in April and November. Volunteer work crews there have removed nearly all lunaria, vinca and holly. The park faces an ongoing battle against blackberry and ivy. Reed canary grass is a new, emerging plant problem, showing up in some areas where blackberry has been removed. Cutting, and eventually shade, might help reduce it over time.
Baltimore Woods, at approximately 30 acres so far, is at an earlier point in the restoration process. Land acquisition is still under way. Plans for this summer include the removal of a large, paved area, as well as the development of a pathway through the park. Much work lies ahead for the volunteer corps to create a new oak savannah where one was long ago, along a bluff overlooking the Willamette River and the St. Johns Bridge. A trail through the park will provide connectivity from Smith and Bybee lakes all the way to downtown Portland.
Damage has been done to our natural areas for a long time. Restoring them is not a quick or easy process. It takes a sustained commitment, over a period of time, to bring back a natural state. Even then, non-native species constantly threaten to re-invade. Oaks grow very slowly. But Nob Hill is ahead of the curve with oaks already growing well in their historic setting. Also, huge advances have been made against unwelcome plants in the last five years, thanks to great support from the City of St. Helens and the many volunteers from the community. It's important to preserve and protect our oaks while we still can, and is a way to bring something of value from the past into our future.
