YOSEMITE NATIONAL PARK, Calif. — Evidence of rock climbing's excesses are visible everywhere around the base of a popular summer ascent here. Dead pines lie decomposing on the eroded rock, their roots exposed by thousands of boot soles. The approach is marred by 40 separate trails braiding around the granite face.

Then, there's the garbage.

In September, volunteers packed out 900 pounds of abandoned rope, snack wrappers and toilet paper strewn around some of Yosemite National Park's most cherished crags.

Millions of Americans have developed a taste for rock climbing, a fad fueled by a proliferation of urban climbing gyms and glamorized by programs like America's Next Top Model, which recently showed its models hanging from climbing ropes. But as neophyte rock jocks head to national parks to test their skills in the great outdoors, some are unwittingly breaking the wilderness ethic governing the sport.

Others are violating federal wilderness regulations by drilling into the bare rock face with power tools.

As the sun crested on a recent morning at Yosemite's Tuolumne Meadows, a group of regulars clipping on chalk bags groused about what they see as an influx of clueless novices, who they assumed were responsible for a heist of $1,000 worth of equipment.

"The next time I see some guy with gear that's mine at the top of the peak, I'm gonna push him off," said Bryan Law, 35, a grin spreading beneath his mustache. "Some people just don't know how to behave."

Iconic among outdoor adventurers as the birthplace of rock climbing in North America, Yosemite's mammoth granite formations have a singular allure for climbers eager to push the limits.

And Cathedral Peak, a 10,900-foot temple of rock rising from the sub-alpine Tuolumne Meadows, is often where newcomers start.

Rookie Ha Pham, 23, hopes to venture up it eventually but said she was concerned the conditions she'd find wouldn't meet her standards.

"They should have signs and stuff and trash cans outside," said Pham, who climbs regularly in the safety of a San Francisco gym. "I don't think they even clean your rocks off for you out there."

Yosemite's full-time climbing ranger Jesse McGahey is on a quest to teach such newbies how to develop technical skills and outdoor ethics at the same time. McGahey, who carries his gun in a fanny pack to avoid startling hikers, prefers to educate newcomers about the wilds rather than ticket them.

But on a recent weekend, when he came across an abandoned dog tied to a tree in the middle of bear country, he felt had no choice but to fine its owner $225 as he came strolling down from the summit.

"In the '70s, people used to teach each other how to climb outdoors," said McGahey, 29. "Now a lot of people come out of the gym and head straight for the woods, with no idea of what they'll find there."