Officers in Poole are renewing their appeal for witnesses and anyone with information to come forward after a heath fire on Canford Heath.
It had been reported to Dorset Fire and Rescue Service at around 10.30pm on Tuesday 16 July.
Poole North Neighbourhood Inspector Ian Roe said: “Dorset Police is investigating this fire which we are treating as arson.
“I would urge anyone who witnessed the ignition of this fire and anyone with information about those responsible to contact Dorset Police as soon as possible.
“Dorset Police, Dorset Fire and Rescue Service and our partners in the Urban Heaths Partnership invest a significant amount of time patrolling the various heathland areas and work hard to educate the public about the dangers and environmental impact of starting fires on heathland.
“Not only do fires like this have a huge effect upon wildlife, but they can quickly get out of control and put the public at significant risk as they spread, especially given the proximity to residential areas.
“We will be continuing our patrols over the coming weeks and will deal robustly with any anti-social behaviour.”
Gaynor Mant, Community Safety Officer for Dorset Fire and Rescue, said: “The incident at Canford Heath was an extremely serious fire. It tied up over 60 firefighters and lots of resources for many hours.
“To have caused such a fire deliberately is a mindless act without any thought for the environment, those dealing with the fire and the safety of residents.
“I would encourage anyone thinking about committing arson to consider their actions and think about their families. If we were delayed in getting to a fire in a relative’s house because we were at a deliberately set fire, could they live with themselves?”
Paul Attwell, Team Manager at the Urban Heaths Partnership, said: “Our partnership works hard to protect and enhance these internationally important heathland sites we are so lucky to have within Dorset.
“Canford Heath is home to all six native species of reptile, Dartford warblers and visiting nightjars, as well as important heathland flora and other fauna. Any fire at this time of year is likely to be even more detrimental to this rare habitat and does result in the death of some of these rare species.
“Recovery of the heathland can take up to 20 years, causing detriment to the future of these species. We ask for anyone visiting a heathland site to be extra vigilant during the warm summer weather and report anything suspicious.”
Witnesses and anyone with information should call Dorset Police in confidence on 101 quoting incident number 16:647. Alternatively, call the free and anonymous Crimestoppers line on 0800 555 111 where mobile phone tariffs may apply.