The trails are quiet now, their trees covered with snow, but away from the forests in the towns and city where the people live a storm is raging.

On the other side are the mountain bikers, a group growing in numbers and influence. “Studies have shown that mountain bikes do less damage to the trails than people walking,” says Bruce Glaser, a promoter of mountain bike races and owner of the Wheel Thing, a bike store in La Grange. “There’s absolutely no reason to ban cyclists from a public space.”

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Restoration activists have long argued that the forest preserves are overtaxed. In recent years volunteers from the Nature Conservancy have actually been removing trees with the permission of the county. “We’re trying to restore the prairie woodlands and wetlands back to what they were before European settlement,” says Keller. “It’s an impossible task, but that’s our goal.”

“The buckthorn has kind of infested the oak woodlands,” says Keller. “They shade out all the native plants and flowers and oak tree growth. So the oak forest comes to a standstill and there’s no succession. We cut down these trees and then we try to plant new trees. It’s the original forest that makes the area so attractive.”

In recent years the sport has soared in popularity. Mountain bikes, which have balloon tires and upright handlebars, now outsell ten-speeds. On warm-weather weekend days, as many as 200 mountain bikers race through the uncharted paths of the Palos preserve. “I can’t tell you how many times bikers have said, “I didn’t know this place existed,”‘ says Glaser. “It’s through biking that they learned about it.”

“The paths created by the cyclists also create small ecosystems. Some birds or insects won’t cross a trail that’s a foot wide. So the bikers are, in effect, dividing one larger ecosystem into several smaller ones.”

Glaser suggests that single trails be closed to bikers, horseback riders, and hikers when the ground is particularly wet. He also contends that most bikers would agree to having to buy a county license to ride in the forest preserves. The money would be used to help maintain the trails.