As the cost of lumber continues to soar, Tennessee’s Department of Agriculture is warning landowners of a budding crime: tree theft.

Reports of disappearing trees have occurred across the state in recent weeks, according to the department.

“We’ve had reports of oak trees, poplar, and some hickory stolen in Middle and East Tennessee,” Agricultural Crime Unit Special Agent LaLonna Kuehn said in a statement. “One of the best ways to prevent this crime is to let your neighbors know if you will be removing timber from your property. If they haven’t heard from you and see harvesting, they should contact you or law enforcement immediately.”

National Parks haven’t been immune from the illegal practice, either. In northern Georgia, the National Park Service reported more than a dozen trees were illegally harvested from Chickamauga and Chattanooga National Military Park last month, according to the Charlotte Observer. Officials have noted white oak is particularly prized in the area’s bourbon and whisky trade, where it is used as barrels, according to the Chattanooga Times Free Press

“Timber theft can be financially devastating to a landowner,” Tennessee State Forester David Arnold stated. “The value of the timber is not the only loss. In most cases, the thieves damage property and negatively impact conservation efforts and wildlife.”