The large Moreton Bay Fig next to the old Sans Souci Bathers' Pavilion should be retained as a historic marker for the area, historian Dr Garry Darby said.
Georges River Council has lodged a development application to demolish the 1930s bathers' pavilion in Water Street after an engineer's report said it was beyond repair.
Dr Darby grew up in Water Street and has written several books about Sans Souci.
In his submission to the council, Dr Darby described the tree as a historical marker.
"It's a significant feature of the landscape and harbours a lot of memories for people because it has always been there," he said.
"A lot of people are well-aware of the tree and would hate to see it go."
Dr Darby said a photograph taken in 1924 showed the tree well-established on the site and that it probably dates from the early 1900s.
It stood next to the boatshed built by George Hughes who also built the original tidal baths.
When he sold his boatshed in 1927 the St George Sailing Club was located at the site.
"So many people for such a long time have looked at this tree and admired it," Dr Darby said.
In his submission, the Kogarah Bay Progress Association secretary Jeff Powy said any future building on the pavilion site should not extend outside the footprint of the existing Bathers' Pavilion or encroach on the canopy of the existing Moreton Bay Fig tree.
In its submission to the Georges River Local Planning Panel, the council said the intention was for the tree to remain.
The provision of a historic marker for the tree was a good suggestion, according to the council's submission to the Georges River Local Planning Panel.
"The provision of a historic marker near the Morton Bay Fig should not only recognise the importance of the tree but also provide a photographic view of its origin." the council's submission stated.
"A condition is included if consent (for the pavilion demolitiion) is granted.
"This is a symbolic gesture that will reiterate the importance of the site and recognise its historic contribution to the local area."