At 9.50pm on Friday crews from Bracknell fire station went to the underpass opposite Larden Way, in Crown Wood, where a pile of rubbish had been set alight.
Then on Saturday, firefighters from Earley station went to Mill Lane, in Easthampstead, to tackle another blaze at 7.50pm, and were there for 15 minutes.
On Tuesday, a crew from Bracknell went to the Iron Bridge in Ringmead at 3.50pm after a pile of rubbish was set alight in Birch Hill.
Chief Inspector Simon Bowden, commander of Bracknell Forest police , said the fires that have been happening sporadically across the borough over the summer could potentially cause another forest fire like the one that devastated acres of woodland in May 2011. He added: "It is a concern because obviously it can lead on to things like the Swinley Forest fires.
"It's got potential to cause huge damage and huge problems and also endanger people's lives."
However, Ch Insp Bowden said antisocial behaviour generally "continues to be down on or equal to previous years", and Operation Lion Cub - where a dedicated police team is on stand-by to respond to antisocial behaviour reported by communities - is running every night of the summer holidays. He said police are also continuing to monitor graffiti - which has been a concern in Martin's Heron and The Warren - and said: "What we can do is work with PCSOs, PCs and Neighbourhood Action Groups. We collect pictures of graffiti we keep a database of all the graffiti tags then we work with schools and local youth groups to identify those tags."
Ch Insp Bowden said policing in Bracknell had not been affected by the Olympics. He said: "We made sure we had more than our minimum resources across the whole period to make sure there's no impact on local policing."
He said Insp Jon Goosey has been overseeing policing at the rowing and canoeing at Eton Dorney but other inspectors have been covering his shifts for Bracknell.
* If you have any information about any of the fires, call police on 101 or Crimestoppers anonymously on 0800 555111.