Winter settles silently on the young fir forest at Chehalem Ridge and the riparian banks of Clear Creek, the marshy Killin Wetlands and the canyons of the Sandy River.
For these and other lands that are part of Metro’s 11,000 acres of natural areas, the next couple of months is a dormant time, a time for plants to shut down and wildlife to conserve energy. Humans rarely visit the natural areas as days grow cold, dark, wet and stormy.
But it is a favorite time for many who know these lands.
"It is a quiet time all around," said Kate Holleran, Metro’s natural resources scientist, who admitted she sometimes seeks the peace and solitude at Chehalem Ridge.
Less than 20 years ago, voters told Metro to preserve and restore healthy native woodlands and watersheds in Washington, Clackamas and Multnomah counties with their support of a $136 million bond measure.
Voters spoke again a decade later, in 2006, with passage of a $227 million bond measure to protect 27 regional target areas, as well as funding to help local municipalities with parks and the Nature in Neighborhood program.
Metro’s natural areas are lifesavers for native wildlife, including some threatened species, by providing food, habitat and even safe travel routes. But they also are deeply important to nearby communities and neighborhoods. Natural areas clean rain and runoff and their plants clean the air. Some that are open to the public offer education and recreation.
"It keeps nature close by, out our back door," Holleran said. "It keeps nature in the neighborhood."
During a recent visit to Chehalem Ridge, Holleran was struck by the quiet. "In the spring, it’s an orgy of sound," she said. "All of those neotropical birds that nest up in those young trees, that feed their young and declare their territory, are gone."
A few over-wintering species stick around – ruffed grouse, California quail, chickadees – but they are focused on finding food to survive. "They only move when they have to," Holleran said.
At 1,180 acres, Chehalem Ridge is the largest single property to join the natural area program. Using funds from the 2006 bond measure, Metro bought the land in 2010 and has begun work that eventually will turn planted timberland into a more natural landscape that includes oak woodlands and older growth forests.
The Chehalem Ridge property is in the very early stages of stabilization, the first step in restoration when Metro takes over an area.
During the drier months, crews have been selectively logging to reduce the young trees from 500 per acre to a more habitat-friendly 100 per acre. Some of the logging roads were closed to let nature reclaim them, or actively decommissioned by arranging fallen logs and planting shrubs.
Fortunately, the Chehalem Ridge area doesn’t have a bad infestation of invasive weeds. At other sites, controlling invasives can be a big part of stabilization. Healthy, diverse wildlife needs native plants. When invasives take over, wildlife suffers.
For instance, at Scouter Mountain, crews recently targeted a 15-acre area where they smashed down weeds and mulched heavily to discourage new growth. Eventually, stabilization helps native plants prevail and forces out the intruders.
Across Metro’s natural areas, the cold, short days told the maples and alders to shed their leaves and stop growing. The conifers were active a little longer before shutting down. The first storms pulled off the weak branches and tree tops. "It’s like the earth is shaking its head hard," Holleran said.
The many creeks that flow through the natural areas are running high from recent rains, and some low lands have flooded, creating habitat for waterbirds.
Chehalem Ridge, which is one of the driest areas in the summer, has seasonal streams that catch rainwater and channel it to creeks that eventually flow clear and cold into the Tualatin River.
After really heavy rains, Holleran said, it’s possible to stand on a slope at Chehalem Ridge and hear the water flowing underground.
Metro crews periodically must step in to repair an erosion problem, or pull blowdown from clogged culverts. And the winter months are the best for pulling invasive ivy and holly. But most human work at the natural areas shuts down for the winter.
The quiet doesn’t last long.
February signals the start of the planting season, a busy time as crews try to get plants into the ground while they still are dormant. Since the first bond measure, Metro has planted more than 1.7 million shrubs and trees on its natural areas. In recent years, an average of 150,000-170,000 plants were planted, Holleran said.
Young, planted forests like those at Chehalem Ridge are among the least valuable to wildlife, so the thinning work will continue. The trees that are left will have an easier time growing, and planting native shrubs and understory will start to establish a richer and more complex environment.
Restoration takes time. It will be years before Chehalem Ridge matures into a natural range of healthy habitats, and years before planners will know what kind of public access the property can support.
"Think about what the metro area will be like 15 or 20 years from now," Holleran said. "Chehalem may be Hillsboro’s and these community’s Forest Park."