Part of the experience of seeing the Tallgrass Prairie Preserve in Osage County is a spine-cracking drive over a gravel road that leads to the vast area where bison, birds and other wildlife roam.

The prairie once spanned 142 million acres. In the park founded 20 years ago, about 39,000 acres that straddle the Oklahoma-Kansas border are preserved. The park draws about 20,000 tourists annually.

Bob Hamilton, who was part of the Nature Conservancy's original effort to establish the preserve, said it is important for the public to be aware of the preservation of the tallgrass prairie.

"But for us, it's not about the visitors," Hamilton told the Tulsa World. "It's about the grass."

Hamilton is science director for the prairie park, which was formed when private land was purchased to create the preserve.

Not far from park headquarters, Hamilton stopped his pickup on the gravel road and looked at one of the few b arbed-wire fences that still cross the preserve.

On one side of the fence, the yellowed grass was waist-high; on the other, it barely reached his knee.

"And yes," he says, "the grass is always greener on this side."

More than 2,700 head of roaming bison keep the grass trimmed.

Most visitors to the park come to see the bison. Hamilton noted that the bison are in the park because off the grass.

The park is celebrating its 20th anniversary this month.

"This place is about conservation," Hamilton says, "not tourism."

"I like to think of the last 20 years as our startup phase," Hamilton said. "Now that we're settled in, we can really get to work."

He said the focus for the next 20 years in the Flint Hills area will be "moving conservation off the preserve."

"We think of the preserve as an incubation site," Hamilton says, "for encouraging conservation across the wider area."

Toward that goal, in recent years the preserve h as developed a sophisticated system of controlled "patch burns" to mimic the role that natural grass fires used to play on the open prairie. Hamilton hopes to see the practice spread to private ranches in the area.

"Fire is a big part of what we do," he says. "Take away fire, and in a generation or two, the prairie will turn into a woodland."

Hamilton said private landowners could adopt methods of "conservation grazing" that are being developed on 12,000 acres set aside for domesticated cattle. He said the method shows that ranching can coexist with natural tallgrass.

He also wants to use easements to preserve grasslands that are now in private hands.

Hamilton said he is concerned that using nearby lands for windmills that generate electricity would disturb the area's ecosystem.

While wind power generates clean energy, Hamilton said the necessary networks of turbines, roads and power grids are a threat.

"I think the next 30 or 40 years will be decisive," he says. "Whatever land that is going to be set aside for conservation will be set aside by then, and the rest will eventually be lost forever."

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