MISSOULA, Mont. -

Prosecutors charged a Missoula man with negligent arson after he allegedly lit a tree on fire.

18-year-old Nathan Irby is accused of using a lighter to burn sap on a tree in Futura Trailer Court just west of Missoula.

Neighbors told NBC Montana they were concerned, especially because of the high fire danger and dry conditions.

Irby pleaded not guilty to the  in Missoula County Justice Court Wednesday. The judge released him on his own recognizance.