Dorset Fire and Rescue Service say that arsonists are believed to have started a fire which destroyed heathland on Ham Common in Poole yesterday.
Large fires at Canford Heath and Studland are also thought to be the result of individuals deliberately starting fires.
The service is calling on people to recognise the serious danger posed by the wild fires to people and property.
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Amanda Houston has the latest weather forecast for the west of the ITV Meridian region.
Amanda Houston has the latest weather forecast for the east of the ITV Meridian region.
Former One Direction star Harry Styles and Hollywood actor Tom Hardy have been in Dorset for filming of their new blockbuster Dunkirk.