Though it is a foggy autumn day, the view clears as I duck under the canopy of tall firs along the North Fork of Deep Creek. The fog is filtered by deep layers of arching tree branches. Steep as the land is, I am happy to climb up and down the canyon walls above the creek.
Thanks to voter support, Metro now owns 27 acres along the North Fork of Deep Creek, including a nine-acre patch of forest acquired in 2015. Though small in size, the natural area contains a habitat uncommon in the developing landscape of Multnomah, Clackamas and Washington counties.
The forest I’m exploring is an old-growth forest with trees more than 400 years old; some 5 feet in diameter and more than 200 feet tall. Many of our resident wildlife evolved in a Pacific Northwest landscape that wore this mantle of towering old trees and dense underbrush. For these resident wildlife, the ones that stay put during our temperate winter, old forests provide the best winter refuge.
It is hard to see the tops of trees as they reach far above the lower canopy layers of small trees, shrubs such as wood rose and red huckleberry, and a carpet of sword fern, Oregon grape and many species of mosses. A hundred and fifty years ago, most of our low-elevation conifer forests were old forests already 250 to 750 years old. Old-growth forests were common. But not today.
Along the way to becoming a forest of giant trees, hundreds of disturbances happen in a forest – trees die, small landslides occur, or lightning strikes smolder unattended -- creating interruptions in the forest world. These innumerable changes over hundreds of years create a decadently rich diversity of habitat niches for wildlife.
Wintering birds are good representatives of wild residents that benefit from big, old trees in complex forests. In winter, the Pacific wren, brown creeper, red crossbills and the iconic pileated woodpecker forage for arthropods in the canopies and deeply furrowed bark of long lived conifer trees.
All of our amphibian species utilize old forests, seeking refuge from hot summer days or freezing winter nights by hiding under and inside of decaying wood. Many of our native bat species, such as the silver-haired bat, roost under the bark or in the crevices of large, old trees.
Put into human perspective, these old forests are a wild, one-stop shopping habitat for many of our common species. Over the course of the seasons, these forests are where our native wildlife thrives.
What kind of restoration work happens in an old growth forest? Not much! Instead of spending time and money trying to restore a degraded habitat, I get to kick back and enjoy the natural processes already underway in old-growth forests.
OK, invasive plants are always an issue. Birds have deposited the seeds of holly and ivy along the North Fork of Deep Creek. Those plants, if not controlled, will over time change the rich variety of native forest shrubs and herbs into a smothering blanket of simplicity.
Metro will cut, pull and remove these invasive weeds. We will work with our neighbors to protect adjacent forest habitat to buffer the older forests along Deep Creek. The rest we will leave to the slow passage of time.
It has done a good job so far.