John Malone has few equals when it comes to structuring complex, hardball financial deals.

As chairman of Colorado-based Liberty Media, the largest international cable-television operator, Malone is estimated to have a personal net worth in excess of $2 billion, seemingly enough for whatever his heart desires.

And what his heart desires is open space.

Malone and his wife, Leslie, have developed a passion for preserving scenic, open land. Together, they've spent a significant portion of their wealth buying up huge tracts and transforming much of it into traditional working cattle and horse ranches. They've renovated ranch houses and historic old barns. They've hired cowboys and their families to manage the ranches and the estimated 18,000 head of cattle they own.

"Open land, especially scenic open land, is an important part of our heritage, particularly in metropolitan communities," he said in a rare interview on the topic. "I think it's very important that land be preserved, especially for future generations. Once that land gets developed, you can never go back."

Charles Bedord, executive director of the Colorado chapter of the Nature Conservancy, on whose board Malone sits, says he's in awe of Malone.

"He's been incredibly supportive of conservation," Bedford said. "He's an incredible thinker. We bring up an issue and he's thought about it six ways to Sunday. He's always six steps ahead of us and incredibly committed to the land."

In Colorado, the Malones own roughly 500,000 acres, including 100,000 acres in Elbert and Douglas counties. They own or lease another 500,000 acres in Wyoming and New Mexico. In Maine, they purchased an island in a scenic bay and put it under a conservation easement, and funded the protection of the enormous St. John's River drainage. And now he's involved with fellow billionaire Craig McCaw in preserving 18 million acres of wilderness and tribal lands in British Columbia.

Malone's signature piece of conservation along the Front Range is Greenland Ranch, the expanse of soft rolling hills that straddle Interstate 25 midway between Denver and Colorado Springs. Thousands of drivers pass through it daily, unaware of how close it came to being paved over with cul-de-sacs and chain retail stores.

Stopping the two cities from linking together had been a goal for many Coloradans, including former Gov. Roy Romer, who made it a priority early in his political career to preserve "the natural break" between Denver and Colorado Springs.

"When you drive into that valley, all that green grass is spectacular. It reminds me of something out of a movie, some beautiful lost valley," said Romer. "I've always seen it as one of the most gorgeous examples of the way Colorado was."

Malone worked with preservationists, primarily Sydney Macy of the Conservation Fund, and funded a conservation easement on the 21,000-acre ranch. He then bought 17,000 acres east of I-25, spending a total of $55 million to take it out of the hands of developers and turn it into a working cattle ranch. Douglas County and Great Outdoors Colorado spent $20 million to buy the remaining 4,000 acres east of I-25, including the original townsite of Greenland, which is visible to motorists on I-25.

"He's been extremely important as a partner to us," said Cheryl Matthews, director of Douglas County's Open Space and Natural Resources. "He's taken wonderful care of the ranch. His people do an excellent job of managing the land and the livestock."

Malone, who's lived in Colorado for 33 years, shrugs off the accolades. "Colorado has been good to me," he said. "I'm not involved in much community stuff. So the Greenland Ranch is our contribution to the area, to Colorado and particularly the Front Range, to think ahead and keep it in its natural state."

Malone rarely gets involved in state political battles, but last spring he fought the Super Slab, a north-south highway proposed by private businessmen. The road was proposed to run well east of the metro area, from Fort Collins to Pueblo, across private lands that could have been taken by eminent domain.

Malone personally lobbied Gov. Bill Owens to fight the road, and he helped fund the opposition, which was successful.

"He's a neighbor out there to many landowners," said Leo Boyle, a lobbyist hired by Malone to fight the proposed highway. "He was concerned about the neighborhood, not just his own property."

Returning the lands to ranching operations is important to Malone.

"What we didn't want to do is buy a lot of land and unemploy a lot of people," said Malone from his offices south of Centennial Airport." He estimates his ranches employ about 65 people, mostly cowboys.

"My wife took charge of upgrading all the ranch houses and historic old barns. The economics aren't very good. We can spend $100,000 on a house, then rent it out for $300 a month. But it's important to provide housing for the employees."

In Elbert County, he owns 19,000 acres along Kiowa Creek and another 50,000 acres along the Bijou Creek drainage, land he calls "one of the most pristine places in the area" because there are no public roads through it.

Malone estimates he owns about 400,000 acres of ranch land in North Park, above Walden and between Encampment and Saratoga in Wyoming. He runs about 10,000 head of cattle there. He currently is in negotiations to purchase several large ranches in New Mexico.

All of the land he and his wife own will go into the Malone Family Trust, to be preserved forever as open space. "The foundation will determine the highest and best use of the lands. That changes over time as a function of the needs of the community," he said.

"What they ultimately get used for - agriculture or parks - will be determined once I'm pushing up posies."

Staff writer Mike McPhee can be reached at 303-820-1409 or mmcphee@denverpost.com.