Ohio dairy farmer Frank Sutliff was grinding cattle feed when he saw them again: all-terrain vehicles shredding his alfalfa fields.
When he shouted to the riders over the engine whine that they were trespassing, they smashed him over the head, he said.
"I went down, and they just started in on me ... hit me, kicked me, broke my leg," said Sutliff, 46. "I crawled into the truck, drove back to the house and dialed 911."
One man paid a $100 trespassing fine. Another spent five days in jail. All denied wrongdoing.
Across rural America, angry skirmishes are increasingly common between property owners and off-roaders squaring off over dwindling open space.
Long accustomed to battling environmentalists for access to public lands, off-roaders now find themselves at odds with farmers, ranchers and a flood of new residents moving to the country for peace and quiet.
As Bob Buster, a county supervisor in Riverside, Calif., put it, "You have these two clashing visions of the countryside."
Nationally, millions of acres have been developed in recent decades. At the same time, use of off-highway vehicles -- a catch-all term for four-wheelers, dirt bikes and dune buggies -- has exploded, up 700% to 36 million users since 1976. Off-road motorized sports are now a $4.8-billion industry. According to buyer surveys by manufacturers, 68% of owners of all-terrain vehicles, or ATVs, ride on private land.
That infuriates landowners like Harlan Brown, who installed heat and motion sensitive cameras to catch off-road miscreants who created a muddy quagmire in his 100-acre Maine woods.
"Your land is not your land," said his wife, Judy. "You think it is, but it's not. It's terrible."
The clashes have made victims of riders as well as property owners.
In North Carolina three years ago, Joshua Woodruff, 22, died of internal injuries after he hit a steel cable while zooming down a private farm lane on his ATV. Farmer Ted Arnold said in an interview he had strung up the cable after making many complaints to police about trash, crop destruction and soil erosion from off-roaders. Arnold said he had liberally posted no-trespassing signs and warned off riders. No criminal charges were filed against him.
State and local officials in Maine, Vermont, Ohio, Minnesota, Wyoming and Michigan in recent years have enacted or are weighing measures to combat illegal off-roading. Homeowners say the laws do little to curb abuse, and off-roaders argue that some violate civil rights.
In California's booming Inland Empire, Riverside County supervisors are expected to vote this summer on what could be the nation's toughest law. The current draft would ban the activity on private property four days a week, even on the riders' property. Riding would be banned outright on private lots under 2 1/2 acres. Grading to create jumps, trails or tracks would require a costly permit and public hearings.
Off-roading "is increasingly dangerous, destructive and very difficult to control, except at huge public expense," said Buster, the Riverside supervisor. The county has long been a mecca for professional dirt bikers and weekend amateurs, and riders are outraged at the attempt to rein them in.
"That is total insanity," said Ed Waldheim, president of the California Off-Road Vehicle Assn. "Off-roading is the most incredible family sport there is, and to deny a kid riding on Sunday ... that is repressive, totally crazy."
Clashes between riders and residents have been frequent in subdivisions that are being carved out of open space, on private property near national forests, and in rural areas -- including northern New England and the California desert -- where snowmobilers, school kids on dirt bikes and others were once free to barrel across unfenced, unposted land.
"Back in the '60s when I was growing up it was like the whole desert was wide open," said Brian Klock, spokesman for the California State Parks' off-highway vehicle program. "I literally would ride anywhere.... There were no signs, no maps, the only thing I knew was when you got near a residence sometimes the landowner didn't like it, and he would be out there with a shotgun."
Phoenix, suburban Atlanta, towns across Connecticut and the outskirts of Colorado cities all have seen urban sprawl bump up against popular cross-country routes, said Russ Ehnes, executive director of the National Off-Highway Vehicle Conservation Council in Sheboygan, Wis. "The problem is the town spreads out and the trail stays put," he said.
Inland California is a particular hotspot.
"My 23 acres near Twentynine Palms are being massacred by off road vehicles," M.J. "Mac" Dube, the ex-mayor of Twentynine Palms and an aide to San Bernardino county supervisor Bill Postmus, said on a recent Saturday. "At 1:15 in the morning they were spinning around two feet from my bedroom, and I'm sick and tired of it."
Dube spoke at a February conference in Joshua Tree entitled "Desert Communities Under Siege -- Take Back the Power."