At Raccoon Creek State Park, 7,572 acres of greenspace 30 miles east of Pittsburgh, there's always an empty picnic table, always room to throw a blanket on the sandy beach along the 101-acre lake.

An hour north of the city at Goddard State Park, the marina is never out of rentable pontoon boats. And Downtown, the First Avenue access to the Eliza Furnace Trail gets plenty of traffic on sunny afternoons, but it's mostly from bicycling and Roller-blading adults. The "Jail Trail," which at one point squeezes between the Parkway East and the Allegheny County Jail, is seldom pedaled by neighborhood kids.

As recently as 10 or 15 years ago, attendance levels were substantially higher at most Pennsylvania county, state and national parks. Fishing license sales were at an all-time high, and it was common to see children massed on back streets and paved trails for after-school bike rides. But reflecting a nationwide trend, young Pennsylvanians are taking less advantage of outdoor amenities, and in some cases are even venturing outside less frequently than kids of previous generations.

In March, the Governor's Outdoors Conference in State College assembled some 300 public health officials, directors of government agencies, park managers, organizers of nature-related nonprofit groups, researchers, retailers and outdoors enthusiasts from across the country to voice their concerns and brainstorm for answers. The two-day series of meetings and lectures attempted to evaluate from various perspectives the growing lack of interest in outdoors activities among children and young adults and gauge its social and economic impact.

For decades, sociologists have carped that kids spend too much time watching TV. But this is more than that. Growing documentation suggests that a generation of Americans has lost touch with the natural environment. Reasons could include urbanization, school districts' concern about injury-related lawsuits, saturation marketing by the computer and electronic games industries, new ways of accessing the media, and a shift in population trends and social values. Health-care workers notice a lack of stamina in America's youth, slower muscle development, lower levels of Vitamin D and acute disinterest in traditional recreational activities.

While no one's suggesting the trend isn't irreversible, some in government and outdoors groups voice concern about the long-term developmental, social and financial impact of a condition that one author has dubbed "nature-deficit disorder." Symptoms include:

80 percent of children under age 2 and more than 60 percent of children 2-5 do not have access to daily outdoor play (according to the Playing for Keeps organization).

The average American child watches TV or plays computer games 6 hours per day -- twice the yearly hours spent in school (The Kaiser Family Foundation).

State parks and the National Park Service report a 10 percent to 20 percent drop in visitation (National Parks Service).

Pennsylvania fishing license sales have declined from 1.1 million in 1991 to 833,000 in 2006 (Pennsylvania Fish Commission).

Between 1995 and 2005, Pennsylvania hunting license sales declined more than 11 percent (Pennsylvania Game Commission).

"The population is aging and becoming more urbanized," said Gov. Rendell. "The numbers of hunters and anglers is declining, and in similar terms people's lifestyles are changing dramatically, limiting their outdoors activities. We need to learn more about the driving forces that are weakening our connection and limiting our use of the outdoors to know how to best address them."

Sean Brady, assistant executive director of Venture Outdoors, says that while the numbers are sometimes hard to quantify, he sees "a huge percentage of young people who are not active outdoors," particularly in urban areas.

"Young people are flooded with options that include lots of things with high-end marketing efforts behind them," he said. "They are aggressively marketed to by sports teams and malls and products."

Saturation marketing by the computer and entertainment industries is increasingly convincing kids and young adults to stay indoors.

"Pick a beautiful picture-perfect summer day [and] go to any park," said Brady. "Once you get a couple of hundred yards away from the parking lot, you won't see many people, even in parks close to urban centers. On the same beautiful day, go to the mall. You'll see lots of people. Go to a professional sports venue and you'll see lots of people. These things have lots of marketing behind them."

Al Wasilewski, operations manager at Raccoon Creek State Park, says competition from commercial water parks such as Sandcastle in West Homestead has visibly reduced the beach crowds at Raccoon Lake.

"You used to have trouble finding a place to put your towel," he said. "It still gets busy, but not as much as 20 years ago."

With no beach area, Goddard State Park and its 1,860-acre Lake Wilhelm primarily serve the interests of anglers. Marina manager Denny Ferguson said last year's boat rentals were down from the previous season, and he sees fewer children in general at the park.

"It used to be families. Now it's a lot of adults," he said. "Children don't seem to be interested in this kind of stuff. They're more interested in computers and things like that. I don't know if it's that the parents aren't taking them [outdoors] or if they just don't want to go."

But the news isn't all bad. At events such as Great Outdoors Week, clusters of outdoors organizations combine their marketing resources to remind people what's out there. Panelists at the Governor's Outdoors Conference suggested the national trend in inactivity could be slowed, if not reversed, at least in part by changing the ways governments manage and market outdoors resources.

Five meetings have been scheduled at locations across Pennsylvania, including one in the Pittsburgh area, to present the findings of the Outdoors Conference and solicit public input on ways to keep people connected to the outdoors. The local meeting will be held 6-9 p.m. June 6 at the Boyce Park Ski Lodge in Monroeville. Additional meetings are scheduled for May 24 in Erie, May 31 in Wilkes-Barre, June 14 in Bucks County's Doylestown, and June 21 in Harrisburg. For more information visit www.connectoutdoors.state.pa.us.