The smell of steaks sizzling on a campfire grill wafted through tamarack and Jeffrey pines as the sun set over the saw-toothed crest of Duck Pass in the Eastern Sierra about eight miles south of Mammoth Lakes, Calif.

The smell of steaks sizzling on a campfire grill wafted through tamarack and Jeffrey pines as the sun set over the saw-toothed crest of Duck Pass in the Eastern Sierra about eight miles south of Mammoth Lakes, Calif.

We sat on folding chairs around the crackling fire, sipping beer, while our cook prepared a dinner of surprising delicacy. Surprising, because in the heart of the John Muir Wilderness, 10,000 feet above sea level, this bespectacled man had conjured a tasty, three-course meal, capped by a freshly baked pineapple upside-down cake and kettle-brewed coffee filtered through a tube sock.

In a nearby meadow, the horses and mules that carried us and our camping gear to the shores of Purple Lake grazed peacefully. It's the only way to get here — unless you hike.

As darkness closed in on the last night of our four-day pack trip, I thought about the poor souls who made the trek on foot to these high-country woods. On the dusty trails, we trotted past them as they politely shuffled out of our way. Some smiled and waved happily. Others held their noses because of the stench and dust we kicked up.

Equestrians and pedestrians have shared trails in the Sierra for more than 100 years, but the relationship has become strained of late as the two sides quarrel over the effect horses and mules are having on the wilderness. As I dozed off under a million shimmering stars in late August, I wondered whether I was witnessing some of the last days of mule packs in the Sierra.

My trip began at an old wooden bunkhouse that once served as the post office for Mammoth City, an 1870s mining camp near the shores of Lake Mary. The mining camp is long gone, replaced by horse and mule stables a few miles outside the ski resort of Mammoth Lakes.

It was within this shady pine forest that a rancher's son named Lloyd Summers started Mammoth Lakes Pack Outfit in 1915, making it one of the oldest in California.

This is where I met John Summers, Lloyd's grandson. He now runs the outfit out of the weatherworn shack. Summers has a graying goatee and hands so rough you could strike a match on them. Ten years ago, he got fed up with the construction business and took over the outfit launched by his grandfather.

At the stables, the head wrangler — a bowlegged cowboy with a Fu Manchu mustache — paired me with Dillon, a 12-year-old quarter horse with a chocolate-brown hide. Nearby, other wranglers took my camping equipment, along with the food and gear for the 11 other guests, and strapped it all onto several stocky, grizzled mules.

We headed out on a five-mile ride along the John Muir Trail to our campsite near Purple Lake. I immediately saw why pack trips are taking heat. Decades of horseshoes and mule hoofs had turned this historic trail into a deep channel — rocky and dusty, like a dried creek bed.

High in the saddle, we rode past half a dozen pristine clear-water lakes, each more dazzling than the last. Skelton Lake was aqua green, bordered by a red, rocky mountain. Duck Lake was vibrant blue with a flat green meadow on one shore and pine groves on the other.

At the top, we crested 10,427-foot Duck Pass and looked down on Cascade Valley, the result of a glacial movement about a million years ago. At 2 p.m., we reached our base camp, near the shores of Purple Lake. Summers and the other wranglers took the animals to rest in the shade of a pine grove before letting them graze in a wide, green meadow nearby.

Base camp is the domain of Del "Cookie" Andrus, a cheerful guy with a white mustache, thick glasses and a wide-brim cowboy hat. As we rode in, he was preparing dinner: meatloaf he had cooked back at headquarters and would reheat at the campsite in a cast-iron Dutch oven.

Despite our remote setting — no electricity, no running water and no bathrooms — I knew at least I wouldn't go hungry.

"Anything you can do in a conventional oven," Andrus said, "I can cook out here."

The camp seemed so organized and civilized, making me wonder whether the critics might have a reason to complain. Isn't this supposed to be a wilderness, a place "where the Earth and its community of life are untrammeled by man, where man himself is a visitor who does not remain"? That's how the Wilderness Act of 1964 characterizes wild places.

But my thoughts were interrupted by a wrangler hollering, "Let's go!"

A few of us had planned to take a daylong ride to the bottom of Cascade Valley to a spot called Fish Creek. Purple Lake drains into the valley by way of several waterfalls that crash over boulders and logs. We saddled our horses and rode the switchback trails, following the waterfalls to the valley, brushing past red Indian paintbrush, purple California thistle and buttercups.

After a hot but relaxing day of trout fishing, we rode back to camp for dinner.

Nearby, in the meadow where the horses were grazing in the fading evening light, I found Summers drinking a beer next to a foot-wide stream. Earlier, he had dropped a couple of six-pack s into a gunnysack and submerged them into the cold water. I popped open a can and listened to him recount the history of packs in the Sierra Nevada.

It began, he said, in the 1800s, when ranchers drove sheep and cattle into the mountains. In those days, the mule packs transported people and supplies between Mammoth City and a place called Fresno Flats. Back then, the packs were a way of life — as automobiles are today — and the Pacific Crest and John Muir trails were the main thoroughfares. Anyone who settled in the Sierra relied on mule packs for tools, medicine and clothes — their very survival.

Summers thinks he is keeping alive a part of history by bringing campers to the Sierra to experience the wilderness the way Muir saw it.

But that vision was dealt a blow in 2000 when a group of Northern California hikers and environmentalists sued the U.S. Forest Service, claiming the agency had approved special-use permits for pack companies in the John Muir and Ansel Adams wildernesses without considering the damage.

The charge was that horses and mules eroded the trails, overgrazed the meadows and left manure piles on the paths. A federal court agreed and imposed restrictions in 2001 on the number of guests, horses and mules and the time they spend in the backcountry.

Summers shook his head. Because of the restrictions, he said, pack outfits have had to increase their rates. He thinks some outfits might go out of business. (Peter Browning, spokesman for the High Sierra Hikers Association, the main plaintiff in the case, said the group didn't want to ban the outfits but simply wanted reasonable restrictions to preserve the wilderness.)

We had mounted up early the third day of our trip for a six-mile ride through the valley, after a hearty breakfast of biscuits and gravy prepared in Andrus' oven. Summers led the group, narrating the ride with historical references dating to the Pleistocene. Right after lunch, we came upon a meadow with blossoming wildflowers and lush, knee-high grass. The meadow is bordered by Fish Creek, a steep mountain and pine groves.

Summers motioned to the green expanse that rippled with each gust of wind. This was the meadow that the lawsuit claimed was "devoid of vegetation due to intensive use by pack stock." The lawsuit cited the meadow as key evidence of the damage caused by the pack companies.

An irresponsible pack owner had overgrazed it nearly 20 years ago, Summers conceded, but he saw the meadow — now green and thriving — as proof of nature's resilience.

We returned to base camp that afternoon, excited to see what Andrus would prepare for the trip's epicurean climax.

It featured that upside-down pineapple cake. First, he melted butter and brown sugar in the Dutch oven. Then, he laid down a bed of pineapple slices and topped that with cake batter. While the cake baked, he grilled steaks over the campfire and heated baked beans on a propane grill. After 35 minutes, the cake was done.

I thought about the hikers in the wilderness who didn't have the benefit of our sturdy mules to carry heavy cooking utensils, gas ranges and frozen meat. Instead of sizzling steaks and cold beer, they sat down to freeze-dried pasta, granola bars and filtered water.

As the sun set over the jagged crest of Duck Pass, a dozen of us ate in near silence. Words would have only ruined the moment.