OREGON — A new front line in the battle to stop the spread of a tree-killing beetle is emerging in Ohio’s public and private campgrounds.

Forestry experts say they likely could contain the slow-moving emerald ash borer if it weren’t for people who unknowingly transport the pest to new areas.

That is why they are concentrating on campers and their firewood.

Inspectors visited campgrounds in northwest Ohio to look for firewood brought into the area despite a ban on moving firewood into the state from Michigan and from quarantined areas of Ohio.

During the Fourth of July holiday weekend, they confiscated 16 loads of firewood.

“It only takes one piece of infested firewood to kill thousands of ash trees,” said Melissa Brewer, a spokeswoman for the Ohio Agriculture Department.

At least two infestations discovered in recent weeks at campgrounds along Lake Erie are likely the result of campers bringing infested firewood to their camp sites.

State officials announced Monday they found firewood at an Ottawa County campground appeared to be infested with the ash borer.

Surveyors now will begin determining if more trees are doomed.

It takes the ash pest about three to five years to kill a tree, but there’s nothing to stop it once it attacks a tree. The ash borer was first found in the U.S. three years ago in Michigan. It was also discovered in Indiana.

Stopping the ash borer now before it moves farther into Ohio is critical. Researchers fear there will be no stopping the pest if it gets beyond the northwest part of the state.

At least a handful of the ash trees that shade dozens of campsites at Maumee Bay State Park near Toledo are dying and there’s little hope for the others that account for about half of the campground’s shady sites.

Those sites are always the first ones taken by campers, said Jim Brower, park director. This fall the park will start replacing the ash trees.

“We’re kind of starting over again. It’s kind of frustrating,” Brower said.

Ed and Betty Rhoads, of Norwalk, were spending the week at the campgrounds and said it’s sad to know that so many trees will be lost.

“We’ve been coming here a number of years and saw the trees grow from the start,” said Betty Rhoads, 70.

Dixie Andersen, 41, and her two daughters sat under the shade of an infested ash tree Monday morning at the campground. The only sign that something was wrong with the tree was a section of bark peeled back by state inspectors.

“We’re not sunbathers,” said Andersen, of Gaylord, Mich. “We keep moving around with the shade.”

The state this summer sent out letters to Michigan residents who plan on staying at Ohio parks to warn them that it was illegal to bring firewood. They also sent information on the ash pest and firewood ban to 900 privately operated campgrounds in Ohio.

Craig Morton, manager at Grand Lake St. Marys State Park in west-central Ohio, said they have posted firewood alert signs at the campgrounds and advise people to buy wood at the park.

They haven’t confiscated any firewood yet, and they can’t check everyone, he said.

“It can be extremely time- consuming and it can be confrontational,” Morton said. “We tell them they need to burn it up and burn it up quickly.”