In late autumn, nature quiets down from the exuberance of summer. A walk reveals every rustling leaf still left on the trees and every crunch underfoot. Although we may begin a hike expecting to satisfy eyes with grand soaring vistas, or cardiovascular system with calories burned, a good hike into the wilderness is also a time to satisfy the ears with the sounds of silence.
Next time you're out in the wilderness, try an experiment: stop and listen, just listen to the sounds. Muir describes a symphony in California's Central Valley:
The water in music the oar forsakes. The air in music the wing forsakes. All things move in music and write it. The mouse, lizard, and grasshopper sing together on the Turlock sands, sing with the morning stars.
Perhaps the best place to find true silence is in Colorado's Great Sand Dunes National Park. Last year, the NPS collected acoustical data on 50 national parks. Great Sand Dunes, in south-central Colorado (photo credit: NPS), is so quiet that future monitoring will have to employ a high-sensitivity microphone to more accurately measure the extremely low sound levels existing in the park. The silence is partly because of the original 1916 law establishing the National Park Service, which orders the agency to preserve "natural soundscapes" along with the scenic vistas and wildlife at each park property. The Department of the Interior planned to permit an energy company drill for oil and gas in the adjacent Baca National Wildlife Refuge. Environmentalists rushed into court, fearing that the park would be ruined by the pounding hydraulics and thundering machinery of oil and gas wells. In September a federal court declared that the drilling would cause irreparable injury to the refuge's significant 'sense of place' and quiet.
Silence can be found elsewhere in the wilderness. Haleakala's crater is comparable to Great Sand Dunes' sound levels. Bryce Canyon is blessed with both dark, clear skies and extraordinary quiet. The landmark 2008 decision limiting snowmobiles in Yellowstone rested, in part, on the noise made by snowmobiles. A few parks are beginning to take actions against human-made noise. For example, Yosemite has a research project, beginning with a baseline that can be used to inform planning and management decisions related to protecting natural sounds in the park while minimizing human-caused sounds -- particularly mechanized sounds like vehicles and airplanes. Park management has replaced some of its valley shuttle buses with quieter buses, and is attempting to discourage airplanes.
John Muir approves:
Few are altogether deaf to the preaching of pine trees. Their sermons on the mountains go to our hearts; and if people in general could be got into the woods, even for once, to hear the trees speak for themselves, all difficulties in the way of forest preservation would vanish.
Starting venturing into the wilderness, your ears are still attuned to human sounds, and it takes a good trail mile or so before the sounds of automobiles fade away. Then you hear a lizard scurrying over a dried leaf, or the distant howl of a coyote, the mating grunts of two bullfrogs, or the soft slither of a snake on sand. Water, in all its variations: dripping from trees, roaring down waterfalls, and curling into ocean waves. You might hear the whisper of the wind in the tall grasses, or the crunch of newly fallen snow.
You might even hear the cries of the pine trees beseeching humans to preserve them.