Editor's note: This is the first part in an occasional series on noise and noise-related user conflicts in Wyoming.

Visiting the national parks and other wild places in Wyoming affords more than an opportunity to record broad vistas and crimson sunsets on film. For some, it's a chance to take refuge in the refreshing solitude, the peace and quiet, absent the mechanical hubbub that typifies urban life.

For others, however, the man-made sounds of all-terrain vehicles or snowmachines are integral to enjoying the outdoor experience.

So what sounds belong, and what sounds don't?

The answers depend upon individual values and tolerances, ranging from those with little or no tolerance for man-made noise, to those with a high degree of tolerance - or who even take pleasure - from sounds associated with motorized recreation.

"Can we find a clear way of negotiating a peace when one group's dream of free and rapid movement runs head on into another group's dream of solitude?" asked Patricia Limerick, professor of history at the University of Colorado and moderator of a recent conference in Boulder.

The question lies at the core of conflicts between two groups of people that both profess to love the outdoors: motorized recreationists versus muscle-powered recreationists. In Wyoming, the issue is often focused on Yellowstone and Grand Teton national parks, where the interests of snowmobilers and snowplane enthusiasts clash with conservationists. But there are other Wyoming and Western conflicts as well: cross-country skiers and snowshoers versus snowmobilers in national forests; hikers and horseback riders versus all-terrain vehicle (ATV) riders on trails; swimmers, canoeists and sailors versus jet skiers; and power boaters on lakes and reservoirs versus fishers.

Pat Williams, a former congressman from Montana and now senior fellow for the Center for the Rocky Mountain West, asked, "What is the proper use of place?" A modern man, Williams drives a car, flies planes and rides ATVs and snowmobiles, he said. Indeed, Williams termed a snowmobile trip he made to Old Faithful in Yellowstone Park as "glorious." Yet his concerns about noise remain.

"The wild is melting away like a snowbank on a July day," he declared, while "noise is slicing through where it has never been before." Wildness is overwhelmed by ever-growing numbers of thrill machines that run about on land, water and snow, or aircraft that give tourists a peek at natural wonders from above.

Bottomline, Williams said, snowmobiles do not belong in Yellowstone: "We need to give silence an opportunity to be heard."

Noise and personal freedom

That stance is almost incomprehensible to Bill Dart, public lands director for the BlueRibbon Coalition, an advocacy group for motorized recreationists. Dart, an ardent snowmobiler, equates snowmobile noise with mobility and personal freedom, saying that "without noise, people would have no opportunity to see" the wonders of Yellowstone.

"I know that my appreciation for nature grows as I see it," he said. Dart said he likes nothing more than to drive to a beautiful place, turn off the engine and soak in the scenery. As for noise bothering wildlife, Dart said he hasn't seen evidence that noise bothers bison along a snowmobile trail. "They just stand there," he said, close enough to touch as he goes by.

No fan of deliberately loud snowmobile engines, Dart said his group encourages reduction of noise on public lands and discourages the aftermarket trade of modifying two-stroke engines to make more noise while gaining power. The BlueRibbon Coalition has also supported the Clean Snowmobile Challenge (held in Jackson in recent years), in which engineering students modify snowmobiles to be cleaner and quieter, he said. Manufacturers have also responded by developing cleaner and quieter snowmobiles, responding to consumer and environmental concerns about emissions and noise.

Mel Wolf, former president of the Colorado Snowmobile Association, emphasized that noise is a very subjective topic. "Noise is not a big deal to me," he said. That does not negate the value of communications, compromise and collaboration between opposing parties, Wolf said. "Court fights are no good, not for anyone."

Helicopter tour operator David Chevalier, president of Blue Hawaiian Helicopters, flies tourists over lava flows, waterfalls and the spectacular scenery of the Hawaiian Islands. "If you do it right, customers forget the helicopter," he said, concentrating on the guide's narration, background music over their headphones and the sights below. Chevalier called his tours "a flying classroom," but acknowledged that noise from his helicopters bothers people on the ground, from residents to hikers in the backcountry. Chevalier is part of a national group that works with the National Park Service on noise abatement by helicopter and plane tour operators - flying higher or further away from people on the ground.

Costs of sound

While loud sounds can accompany economic activities, economists are familiar with the costs of sound as well. A study by economist Charles Komanoff and mathematician Howard Shaw, "Drowning in Noise: Noise Costs of Jet Skis in America," calculated that jet skis impose approximately $900 million of noise costs on U.S. beachgoers each year. Smith contends that many beachgoers avoid jet ski noise and seek out quiet.

The authors tapped extensive literature correlating noise from highways and airports with reduced home values. For example, a Federal Aviation Administration study found a one-decibel change in cumulative airport noise exposure usually results in a 0.5 to 2 percent decrease in real estate values. Several studies had derived a decibel-dollar relationship, associating each extra decibel with a certain percentage loss in the sale price of houses. Komanoff and Shaw applied this concept to calculate the dollar loss in amenity for each person subjected to jet ski noise. (See http://www.nonoise.org/library/drowning/drowning.htm .)

Les Blomberg, executive director of the Noise Pollution Clearinghouse, said logistics defeated an attempt to do a similar study on the noise impacts of snowmobiles and ATVs. While jet skis are necessarily concentrated on lakes and reservoirs where people congregate for recreation, snowmobiles and ATVs are broadly scattered.

"We do know from studies that motorized recreation along a trail tends to create a mile-wide footprint of noise," Blomberg said. An upcoming project will focus on obtaining trail maps and then overlay the sound footprint in various states, he said. "I think that'll show that in some states, like Vermont, there's almost no place you can go without the background noise of snowmobiles and ATVs."

In the wide-open spaces of Wyoming, there are places where no motorized recreation noise intrudes, Blomberg said, but they are remote and difficult to reach.

Soundscapes

Despite assertions that noise is subjective and "no big deal," there's a growing body of science that indicates motor noise is much more than an aesthetics issue.

Bernie Krause travels the world to record natural soundscapes, as president of Wild Sanctuary, Inc., an internationally renowned resource for natural sound and media design. Based on one of the largest and most comprehensive wildlife sound libraries in private hands, the collection includes 3,000 hours of material representing nearly 15,000 species. His tape-recording library includes natural soundscapes that are now extinct, eclipsed by development.

Krause's analysis of recordings includes converting natural and man-made sounds into visual format on paper, much like a seismograph records the vibrations of earthquakes. By listening and looking at recordings, Krause said he's realized that "animals are like instruments" and interact in intricate relationships in what he calls a "biophony." The premise is that in an undisturbed natural soundscape of a given habitat, all vocal creatures are heard in a symbiotic relationship to one another, much like instruments in an orchestra.

Recordings around the world seem to support the theory of biophony - that vocal creatures make room for each other and play off of each other.

Another discovery by Krause is that loud mechanical noise - a jet, chainsaw, motorboat or snowmobile - disrupts or breaks the patterns of biophony, and that it takes time for the patterns to come back after the roaring engine departs. (See the Mono Lake recordings of spade foot frogs.)

Krause has also made recordings of snowmobiles in Yellowstone. His analysis of the acoustics of two- and four-stroke snowmobiles shows that four-stroke sleds are indeed quieter, but that the sound carries further. He also found that groups of snowmobiles generate louder decibels than individual machines.

"I think the answer is clear," said Krause. While snowmobiles are "great fun, they do not belong in the park," he said. While snowmobilers want to see the winter wonders of Yellowstone, Krause said he wants to hear those wonders.