MILLINOCKET, Maine — People are illegally tapping into maple trees in Maine to steal sap that, when cooked, creates the sweet, dense syrup that sells for about $65 a gallon, Forest Ranger Thomas Liba said Tuesday.

Liba, who was in town investigating two sap thefts, said most landowners are not concerned about the stolen sap, but rather the damage done to their trees.

“Their business is to grow trees and tapping the trees creates a wound that creates a stain,” Liba said. “The value of that first log [is ruined]. There is a lot money in that first log.”

“Last year, some very high value trees were tapped,” said Jeff Currier, the regional forest ranger who oversees activities in southern Washington County as well Hancock, Penobscot and Piscataquis counties.

The trees were left damaged with open drill holes and the thieves also left trash behind, he said.

The thefts occur every year, but this year more have been reported. Those who go onto private property to steal sap can face trespassing, theft or criminal mischief charges, Liba said. He said he knew of a dozen cases under investigation so far this year.

“We are seeing an increase in the theft of maple sap across the state,” Currier posted on the group’s Facebook page Tuesday morning.

“Mostly what is going on is we’re hearing complaints from landowners saying they’re out on their property and come across this bucket with tubes coming out of the tree,” Currier said by phone, describing the equipment needed to tap a tree for its sap.

Surveillance equipment and other investigative techniques are used to catch those stealing sap and damaging trees, said the Maine Department of Agriculture, Conservation and Forestry ranger.

The sap from each maple has a different sugar content, but in general it takes approximately 40 gallons of sap to create one gallon of syrup, the Maine Sugarworks website states. The tapping season in Maine only lasts between four to six weeks, and generally starts in late February or early March, the website states.

“It’s a statewide issue and it’s a growing issue,” Currier said of the sap stealing.

Those who find sapping equipment on their property without prior permission should contact the Maine Forest Service toll-free at 800-750-9777.