ACADIA NATIONAL PARK – Arthur and Mary Varricchio used to pitch a tent when visiting Acadia National Park. These days, they’re more likely to get a motel room with air conditioning, clean sheets and a soft pillow.

“We were tougher 20 years ago,” said Arthur as he and his wife took a break from a brisk ride on mountain bikes through the woods on the park’s dirt paths. “Now we’re gravitating toward, ‘Isn’t this a nice mattress.”‘

The Varricchios, who are in their 50s, illustrate a growing trend for baby boomers to forgo camping, especially in tents, when they head outdoors.

Tourism experts say boomers’ preference for cushier vacations is contributing to a decline in campers and visitors at parks nationwide.

At Acadia, annual visitation fell 15 percent between 1999 and 2004. Only 72,000 people camped out there last year, a drop of 22 percent in the past decade. Nationwide, camping at national parks fell 12 percent between 1999 and 2004.

The aging population is just part of the reason, said Jim Gramann, a professor at Texas A&M University and the visiting chief social scientist for the National Park Service.

Other factors include hectic lifestyles, competing recreational options, an uncertain economy, a fall in international travel to the United States, shorter vacations and even an increase in ethnic populations unfamiliar with the park system.

“As people get older they may stop visiting parks for health reasons or because they’ve already been, and the younger visitors who are more technologically sophisticated and who have grown up in a digital environment may not be attracted,” he said. “People are asking, ‘Do you have wireless in your campground?”‘

As no-frills camping declines, boomers are opting for recreational vehicles, dude ranches and lodges. They’re also taking amenity-filled vacations on cruise ships and buying vacation homes near the beach or mountains, said Derrick Crandall, president of American Recreation Coalition in Washington, D.C.

That’s not to say that parks and other outdoor destinations don’t get huge crowds. There were 276.9 million visits to the National Park System last year – 2.2 million of them to Acadia. Many parks have reached carrying capacity and can barely handle more visitors, and anybody who has driven to Acadia in the summer can attest to the traffic.

By comparison, combined attendance at Major League Baseball, National Football League and National Basketball Association games last season was about 110 million.

People for decades have been drawn to Maine for its outdoors allure, whether to climb Mount Katahdin, fish for trout and salmon, hunt deer and moose, or camp in the North Woods.

L.L. Bean made his fortune trading on the state’s reputation as an outdoors paradise. Henry David Thoreau has inspired millions of readers with his writings on Maine’s deep woods and Katahdin, the northern terminus of the 2,174-mile Appalachian Trail.

But the number of people going to those areas is down.

Visits between 1999 and 2004 are off by 16 percent at Baxter State Park, nearly 18 percent in the North Maine Woods and 22 percent at the famed Allagash Wilderness Waterway. The numbers are down more than 6 percent at Maine state parks other than Baxter.

Heather Haskell, the assistant naturalist at Baxter, said one theory is that visitors are seeking out what is called “soft adventure-style recreation,” where they hike, fish or enjoy other outdoor pursuits during the day, but want to eat a nice dinner at a restaurant and to sleep in a bed at night.

In the North Maine Woods, people are visiting for shorter periods of time, said Al Cowperthwaite, whose organization handles camping reservations for the 3.5 million-acre region.

“People still like to have a remote experience, but they want to do it in three days and be back home connected to the Internet and their cell phones that are ingrained in our society these days,” Cowperthwaite said. “I guess we’re in an accelerated society.”

That’s especially so for kids, said Butch Street, who runs the National Park Service’s statistics office.

“These kids are looking for high-powered stuff, and the idea of watching a sunset is boring for them,” Street said. “I don’t think they understand that the idea is to give your mind a break.”

On the first day of summer at Acadia, the Varricchios, who live outside Boston, rode their bikes while on a weeklong vacation. They’ve been coming here for more than 20 years.

He’s an electrical engineer and she’s a legal secretary, and they like to relax during vacation. The cell phone goes in the glove compartment to be used only for emergencies. But they see others in the woods carrying cell phones.

Visitors looking to escape the fast pace and congestion of modern living may welcome smaller crowds at national parks.

But numbers will rebound because surveys show that people are having a good time and a quality experience at parks, said John Daigle, an associate professor of forest recreation management at the University of Maine.

“I don’t think this is a long-term trend. I think this is a short-term trend and that visitation will go up again.”