Bozeman, Montana (FORTUNE) -- "I don't want to own every ranch," Ted Turner once said. "I just want to own the ranch next door."

This is the kind of thinking that has made Turner, the restless 67-year-old cable television billionaire, the largest private landowner in America. Turner, the former vice chairman of Time Warner (Charts) who left the company's board in May, owns 15 ranches in seven states, covering 1.9 million acres. That's 3,000 square miles - bigger than Delaware or Rhode Island. (Time Warner is the parent company of Fortune and CNNMoney.com.)

A visit to one of those ranches - the 113,000-acre Flying D ranch in southwestern Montana - demonstrates that the Turner ranches stand out not only because of their size, but because of the values that drive them.

The ranches have three related missions, according to Russ Miller, general manager of Turner Enterprises, which operates them. They are to make money, to protect the environment and to promote the conservation of native species.

On all three counts, the ranches appear to be performing well.

Start with the bottom line. Not every ranch makes money, but as a group they are profitable, says Miller, a tall, gray-haired, straight-talking man who bears a slight resemblance to his boss.

The ranches have diverse revenue sources. The most visible is the sale of buffalo meat. Much of it is sold through Ted's Montana Grill, a fast-growing chain of about 50 casual restaurants, the newest of which just opened in midtown Manhattan. (Turner oversees the restaurants with a partner, George McKerrow.)

The ranches also bring in income from forestry, farming, commercial hunting and fishing, and oil and gas leases. Yep, Turner, the renowned environmentalist, has energy companies pumping natural gas out of deep wells on his massive Vermejo ranch in New Mexico.

As for protecting the environment, here, too, the Flying D gets high marks. One example: The Douglas fir forests that cover hillsides all over the ranch are regularly thinned out, so that they do not become too dense and a fire hazard. Sometimes the ranch uses a helicopter to drag out the trees. That's expensive, but "we don't want to put any more roads in than we have to," Kussler explains.

Turner also gave all the development rights to the Flying D to the nonprofit Nature Conservancy when he bought the property in 1989 for $21 million. Says Miller: "This ranch will always be open space, on the flanks of the rapidly developing community in the Gallatin Valley." Up the road at the Big Sky resort, condos are sprouting faster than Montana wheat.

Turner's plan to conserve native species, meanwhile, is paying off, too. On a tour of the Flying D, we pass a bald eagle and a coyote, as well as hundreds of bison. "Ted wanted essentially to turn the clock back as best he could," says Kussler. Programs are underway to save ferrets, wolves and the red-cockaded woodpecker. "Biodiversity is the key," Kussler says.

The return of the bison to the West is an amazing tale, driven in part by entrepreneurs like Turner. Between 30 and 60 million bison once roamed the plains, a number that dropped to fewer than 600, according to the National Park Service. Turner himself now owns about 46,000 bison, about 3,500 of which live at the Flying D.

The business of selling buffalo meat, though, hasn't gone as smoothly as the effort to bring back the big hairy beasts. Americans don't seem to have a well-developed appetite for buffalo, which is sold mostly at natural supermarkets like Whole Foods Markets (Charts). "We couldn't give bison away four years ago, basically," Miller says.

The arrival of the Ted's Montana Grill chain has helped. About 60 percent of diners, many more than expected, order bison steaks or burgers. You can't find a Ted's Montana Grill in Montana, by the way; the nearest outlet is about 700 miles away, in Denver.

Bison sales are now on the upswing, but on a small scale relative to beef. According to Miller, about 30,000 to 40,000 bison are killed every year. By comparison, more than 100,000 cattle are killed each day.

The Flying D also makes money by charging about 30 hunters each year about $12,000 each to spend a week on the property, trying to shoot a trophy elk. About 2,500 elk live on the ranch.

Bringing in wealthy hunters has caused some flak among Turner's Montana neighbors, but not as much as a plan to kill the brook and rainbow trout in Cherry Creek, which runs through the property. That effort was undertaken at the request of state fish and wildlife officials who want to introduce the westslope cutthroat to the creek; the trout, which aren't native to the stream, had to be eliminated first.

Turner agonized over the idea of killing fish, but he eventually agreed to allow the carefully-monitored effort to go forward. "Poisoning a stream back to life" is what one newspaper called it.

Turner himself spends 80 to 100 days a year in Montana, where he owns several ranches. Turner loves to fish and walk the land, but he also stays on top of ranching operations, much as he used to monitor CNN and the Atlanta Braves during his days as a media mogul.

"He gives people a lot of autonomy," says Miller, a one-time banker who has worked for Turner since 1989. "That doesn't mean he's dispassionate or disinterested."

Ted Turner? Dispassionate? Not likely.

(Disclosure: PERC, a non-profit research group based in Bozeman, arranged for the visit and paid my expenses to attend a conference of journalists on environmental issues in the West. PERC promotes market-based solutions to environmental problems.)