MONUMENT - Some people might find humor in a 10-foottall likeness of the cartoon character SpongeBob Square-Pants painted onto a crumbling chimney in the middle of the woods.

U.S. Forest Service officials certainly don't.

"I didn't chuckle," said Al Kane, a Forest Service archaeologist. "I kind of started crying."

Officials are asking the public to help them find those responsible for this unauthorized piece of art, and stop what they say is a growing number of vandalism incidents in Pike National Forest.

"For whatever reason, we're seeing an increase in graffiti and tagging activity," said Tom Healy, Forest Service law enforcement officer.

The vandalized site is the remains of a cabin built around 1914, when the area was the Forest Service's tree nursery for the Rocky Mountain region. It's near the Monument Fire Center, off Mount Herman Road in the foothills west of Monument.

The cabin was used as a home for the manager and abandoned in the 1930s. The agency moved its tree nursery to Nebraska by 1960, Kane said.

All that remains of the cabin are the chimney, debris and the foundation, and there are no markings to distinguish it from any other abandoned cabin.

"This building is a historic building, even though it may not look like much more than concrete walls," Kane said. "We would consider anything that's associated with the Monument Fire Center and the old nursery as historically significant."

It will cost several thousand dollars to remove the paint this summer, Healy said. Officials plan to put up signs that indicate the site's historic nature.

Healy said officials depend on forest users to help them solve and prevent such incidents, by reporting them to local law enforcement or calling the nearest Forest Service office.

Officials spoke about the vandalism Thursday at the Forest Service's annual "Monument Media Day," with demonstrations and interviews with the Pike Hotshots, one of five teams in Colorado that respond to U.S. forest fires.

The 20-person crew is based at the Forest Service's Monument Fire Center, on the site of the old nursery, but they spend little time there. Thursday marked the beginning of their active-duty season, and they don't expect to be around much.

They are sent into forest fires to dig fire lines and battle the blazes.

"Based on other years, I don't expect much more than a week or two at home until October," said team superintendent Alissa Roeder.

As for solving the SpongeBob mystery, officials have no leads.

Someone took a long time doing it and had the foresight to bring four colors of paint, officials said. It's a short walk from the nearest road.

Asked if he had any suspicions about the kind of person who would paint a giant SpongeBob here, Healy said, "I don't know enough about them to know.

"Apparently they are SpongeBob fanatics."