Arthur and Mary Varricchio used to pitch a tent when they visited 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," Arthur said as he and his wife took a break from a mountain bike ride through the woods on dirt paths. "Now we're gravitating toward 'Isn't this a nice mattress?' "

The Varricchios, who are in their fifties, illustrate a growing trend of baby boomers forgoing camping. Tourism experts say boomers' preference for cushier vacations is contributing to a decline in campers and other visitors at parks nationwide.

At Acadia, annual visitation fell 15 percent from 1999 to 2004. Only 72,000 people camped here last year, a drop of 22 percent in a decade. Nationwide, camping at national parks fell 12 percent from 1999 to 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 visitors, shorter vacations and even an increase in ethnic populations unfamiliar with the park system.

"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?' "

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 the American Recreation Coalition.

The declines do not mean the parks are deserted. 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 some are trying to encourage visitors to park their cars and use shuttle buses.

Visitation also is down sharply in Maine's rugged North Woods, a region that has drawn people for decades to camp, climb Mount Katahdin, fish for trout and salmon, or hunt deer and moose.

The number of people visiting Baxter State Park from 1999 to 2004 was off by 16 percent, compared with more than 6 percent at other Maine state parks. The numbers were down nearly 18 percent in the North Maine Woods -- a 3.5 million-acre swath of commercial forest properties that allow visitors -- and 22 percent at the Allagash Wilderness Waterway.

Heather Haskell, the assistant naturalist at Baxter, said one theory is that visitors are seeking "soft adventure-style recreation," where they hike or fish during the day but want a nice dinner at a restaurant and a bed to sleep in.

According to experts, baby boomers are eschewing boating and biking in favor of dude ranches and lodges.

Acadia National Park in Maine, where Judy Sperry and Jim Sandberg of Burlington, Vt., enjoy a fire, saw a 15 percent decline in camping.