At 10.23pm on Saturday (27) one crew from Dogsthorpe and one crew from Stanground were called to a fire on Edgerley Drain Road in Fengate, Peterborough.
Firefighters arrived to find two fires in the open and extinguished them using hose reels. They returned to their stations by 11.30pm.
The cause of the fire was deliberate. Anyone with information should contact police by visiting www.cambs.police.uk to submit an online report or call Crimestoppers on 0800 555111.