A 16-year-old boy from Poole has been arrested on suspicion of arson and continues to help the police with their enquiries.
Inspector Ian Roe, Poole North Neighbourhood Inspector said: “This arrest demonstrates our commitment to a robust investigation of these alleged offences and we continue to appeal for witness to contact us on 101 in strict confidence.
“We continue to work closely with our partners to protect the public and the delicate heathland environments from the danger and long term damage that fires like these cause.
“Dorset Police, Dorset Fire and Rescue Service, Urban Heaths Partnership Wardens and volunteers continue to patrol in key heathland areas. I ask the public to remain vigilant and to report any suspicious behaviour especially in the prevailing hot and dry weather conditions.”