PROVO — Fire investigators are still looking for answers in a human-caused fire that scorched nearly half an acre along the Provo River Trail around 2500 W. Boat Harbor Drive Thursday morning.

A 911 call came in around 9:30 a.m. and two Provo stations responded to find an area near the so-called Alligator Park in flames, said Provo Fire Marshal Jim Guynn.

The cottonwood trees that line the trail and their cotton-like buds catch fire quickly, Guynn said. He said the callers initially reported seeing two individuals in the area who looked as if they might be trying to put the fire out.

But when they were approached, they ran away, Guynn said.

"It may have been an accidental fire, and they were trying to put it out and got nervous," he said. "Or it may have been intentional."

The fire was knocked down fairly quickly.

"It only burned about half an acre, the problem is the amount of money that it costs to keep running fire department resources around," he said. "It was more of a nuisance fire. We certainly don't need that right now."

With the Fourth of July holiday, Guynn asked everyone to be especially careful with fireworks.

He also reminded those who use fireworks that it's against the law to discharge them within 20 feet of grass, bushes or trees that could catch on fire.