A Big Island high school is stumped by the disappearance of five large trees, which police are investigating as a felony theft.

Five 20-year-old kou trees native to Hawaii have been stolen over the course of about a week, Waiakea High School principal Kelcy Koga said Wednesday.

When the first tree was taken early last week, school officials found it odd but when three more were taken later in the week, they called police. The fifth tree was discovered missing Tuesday morning.

“It’s really unfortunate that people would resort to taking from the school,” Koga said.

Koga has since learned that the wood is expensive, used to make items such as bowls, bracelets and canoe paddles. Hawaii police estimate the trees to be worth a total of about $4,500.

Before the thefts, “they were just trees on campus that our custodians took care of,” he said.

The school’s athletic director who does woodworking as a hobby told Koga about the trees’ value. “He’s definitely not a suspect,” Koga said with a laugh.

The Hilo school sits on more than 40 acres and four of the trees were taken near the student parking area, which is away from the main road.

Koga said he believes that 10- to 15-feet tall trees were taken during the night and were likely cut down with a hand saw that didn’t make too much noise.

Police are seeking tips from anyone with information or those who may have seen suspicious activity. Tipsters may be eligible for a reward of up to $1,000.