A blaze was reported to Dorset Police by the fire service at around 12.40pm on Friday, July 24 at the heathland near Knighton Heath Golf Club in Poole.
Officers attended the scene to support firefighters and have since confirmed that the fire is believed to have been started intentionally.
Police constable Taylor Goodright of Dorset Police said: “We are continuing to carry out enquiries into this incident and I am appealing for anyone with information about what happened to please contact us.
“I am also keen to hear from anyone who witnessed any suspicious activity in the area around the relevant time period.”
Anyone with information is asked to contact Dorset Police online or by calling 101, quoting occurrence number 55260113148.
Enquiries remain ongoing.
The club previously reported a decade of vandalism, including damage to greens, graffiti and two golf buggies being taken on a joyride.