A small, heart-shaped body of water aptly named Green Lake lies at just under 9,000 feet on the western side of the Tetons, deep within the Jedediah Smith Wilderness area of Wyoming. Mirroring the surrounding conifers, the surface of the lake rests perfectly still this fall evening.

From the trailhead, it’s a little over five miles and 2,000 feet of elevation gained to the snug knoll where I’ve pitched my tent. Sitting in my sling chair, I take in the view: granite cliffs, high ridges, and sweeping tundra, the alpine grass, willows, and fireweed a rippling tapestry of burgundy, lavender, saffron, straw-yellow and burnt umber. A sickle moon hangs in the fading blue sky as a Swainson’s thrush sings its liquid, rising song. There’s not another sound, except the faintest tinkle of the stream entering the lake beneath my camp.

This stillness was once the entirety of the world, a base line quiet of wind and waves, of bird, whale and human song. This highly diverse natural symphony has steadily vanished worldwide since the dawn of the Industrial Revolution, replaced by a cacophony that has become the background to our everyday lives: the roar of jets, the rumble of traffic, the racket of construction.

You have to go to really wild places to reconnect with stillness on a grand scale, and it’s a nice coincidence that I’m camped this evening in one of the wilder places of the lower 48 states in this year of the 60th anniversary of the signing of the 1964 Wilderness Act. The legislation was the product of a group of visionary foresters and writers, and it contains one of the more memorable lines ever written about the relationship between humanity and nature: “A wilderness, in contrast with those areas where man and his works dominate the landscape, is hereby recognized as an area where the earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain.”

Today, nearly 112 million acres of wilderness have been permanently set aside from development in the United States, and the natural attributes of these landscapes remain untrammeled by roads or industry, protecting hundreds of intact ecosystems and countless wildlife populations while affording unspoiled recreation to hikers, skiers, horse packers, wildlife watchers, anglers and hunters. These open spaces have also lifted the spirits of millions of visitors.

Despite these notable achievements, the United States still hasn’t protected the full ecological diversity that lies on federal lands, neglecting to include temperate forests and grass and shrub lands. Even if the 16 million acres currently designated as Wilderness Study Areas were fully protected, the United States would have set aside, by my calculation, only 5 percent of its land beyond the reach of development.