“Dude,” Jeremy said, kicking at the underbrush. “Don’t disturb that malt liquor can. It’s an important part of our heritage.” True enough. Before the perfidious hand of the White Man made its play, oak and madrona trees shaded native grasslands along the bluffs above the Willamette. Now, beside discarded Colt .45 rounds, invasive species like Himalayan blackberry and Scotch broom run amok. On occasion, the plants have ignited into raging wildfires—a boon to alarmist local TV newspeople, but for bluff-side property owners, not so much. The degree to which this corrupted landscape can be enjoyed as a “natural area” depends on an individual explorer’s ability to appreciate abandoned shopping carts rusting away in the scrub. We find a particularly fine specimen about 100 yards down the path.

And yet our trail soon levels out in a little bowl carpeted with ferns and splintered branches. Dry, severed ivy vines hang from crooked maple trees and summon an image of a young, glistening Tarzan swinging his way from branch to branch, ululating with abandon. The light, filtered through the dense canopy above and limited by the claustrophobic ravine walls, takes on an oozy, surreal quality. The flora is spongy and ankle-sucking, the footing uncertain. Up ahead, we spy the outline of some man-made structures, a little lookout fashioned from plywood scraps—like a duck blind, except I’m pretty sure the architect wasn’t hunting ducks—and a rustic tree house. Jeremy clambers up the four-step ladder to a wooden platform about six feet off the ground. It’s just big enough for one small person to stretch out on.

Someone, at some time, decided this would make a secure bivouac. Not like it’s going to become a UNESCO World Heritage Site or anything, but the tree house serves as a telling cultural artifact of this landscape’s present state of feral abandonment. As it happens, that state might not prevail for long. Shiny signs along the cliff announce a government project to wipe out invasive plants and restore the escarpment to its original, oaky state. Out of curiosity, I called the project’s manager, Mark Wilson, before my trek into the urban jungle. He explained that some big, blackberry-fueled fires early in the decade unnerved city officials, so they formed an interagency task force—which, in turn, created a multiyear project funded by the Federal Emergency Management Agency (good for something!) to re-primordialize this ragged sliver of North Portland.