Firefighters were called to reports of a tree alight at the rear of a house on Thorton Road in Croydon.
Part of a tree was damaged by fire. There were no reports of any injuries.
The fire is believed to have been caused by a bonfire which spread out of control.
A London Fire Brigade spokesperson said: "We would urge people to consider if their bonfire is necessary and to take care if you’re burning waste at home.
“Always check your local authority’s advice on bonfires and follow our safety tips, such as never using paraffin or petrol, building your bonfire clear of buildings, sheds and fences and never leaving your bonfire unattended.
“If you do have a bonfire at home, be mindful of your neighbours and consider that smoke could cause difficulties and be dangerous for people with respiratory problems such as COPD or asthma.”
The Brigade was called at 0528 and the fire was under control at 0628. Fire crews from Norbury fire station attended the scene.