The blaze engulfed the tree on which the alleged vandals had thrown old tyres.

Crew from the Metropolitan Fire Services and the State Emergency Services were at the scene and contained the flames that picked up momentum due to the slight breeze.

Beaurepaires Whyalla branch manager Mike Cain said the area where the tyres were kept was fenced and locked.

He reached the scene after receiving a phone call and was waiting for police to conclude investigations.

Senior fire officer Berry Hammond said the fire was lit deliberately.

He said no source of ignition was found and police are investigating to get more details.

Senior Sergeant Steve Sims of Whyalla Police said the case was being treated as arson.

He said investigations have started and appealed for information from members of the public.

“There are people out there who know about this incident and may have been a part of it,” Senior Sergeant Sims said.

“We are appealing for information so that the culprits are taken to task.”

A Whyalla News employee who was passing the scene during the fire said the flames were big and the tree trunk and branches were up in flames.

Charred remains of the tyres that were thrown onto the tree branches to fuel the fire in the tree hung from half burnt branches on Tuesday morning.

Meanwhile police are continuing investigations into the fire that damaged a shed in the abandoned Scott Street School two weeks ago.

The building is being demolished for new developments.