Police say a fire within a field to the rear of Meadowview Road, Turriff, was started deliberately.
The Scottish Fire and Rescue Service were called to a bail on fire along with Police at around 7.30pm on Saturday, October, 3.
A police spokesperson said: “Enquiries are at an early stage but officers are keen to trace a number of youths aged about 12 to 13, who were in the area at the time.”
Inspector Jamie Harrison of the Formartine Community Policing team said: “The emergency services attended this incident quickly and the damage, which was around a low three figure sum of money, was fairly minimal. The fire did not spread to the Knockie Woods but the consequences could have been much more severe.
“Enquiries are ongoing but we would urge anyone who has any information about who may have started the fire to please call Police Scotland on 101 or Crimestoppers on 0800 555 111 if you wish to remain anonymous.
“Increased patrols will be carried out in the area but if you have any concerns I would urge you to contact police on 101.”