The fires have been on farmland in areas around Newton Abbot, Teignmouth, Paignton and Dawlish.
All the incidents involved a number of fire crews attending the scenes for long periods of time.
Safety advice has now been issued to farmers on how to reduce the risk of arson, including preventing easy access and installing security.
Raw sewage pours into landmark Devon river
Storm overflows gush into waterway for 40 per cent of year
Work underway to return shingle to East Devon beach
Bulldozer in action for Storm Goretti clean up
Car park fees increase at Devon beauty spot
Northam Burrows season ticket to rise
Tank shell shut downs recycling centre
No one was hurt
Exeter's Royal Clarence hotel to be restored
'Progress is moving fast'
