East Sussex Fire and Rescue Service were called shortly before midnight to reports of a fire in Crowborough Road in the Duddleswell area of the forest.
"Approximately 5 hectares of gorse and undergrowth were well alight," a fire service spokesperson said.
"Four Land Rovers were sent to the scene along with six fire engines.
"A thermal imaging camera was used to check for hot spots.
"The conditions were challenging for crews who worked hard to bring the fire under control."
The fire service warned that dry conditions can mean that fires start very easily.
The spokesperson continued: "Each year UK, 1,700 farm buildings and 66,000 acres of grassland are destroyed by fire.
"Help us to help you by taking just a few simple safety steps to prevent a devastating fire in the open:
• Avoid using open fires in the countryside
• Sunlight shining through glass can start large fires - take glass bottles/jars home or put them in a waste or recycling bin.
• Keep young children and ball games away from barbecues.
• Extinguish cigarettes and other smoking materials properly.
• Only use barbecues in suitable and safe areas and never leave them unattended.
• Ensure that your barbecue is fully extinguished and cold before disposing of the contents.
• Obey safety signs.
• Never throw cigarette ends out of car windows - they can ruin whole fields of crops."
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