Their removal is part of a council policy to remove and replace trees within the central business district when they get too large, Ms Bainbridge said.
"During an average year, up to three or four of these trees may be replaced with younger specimens. This approach relates specifically to plane trees, which are fast growing and need to be replaced every 10 to 20 years because of their impact on underground services and root damage to footpaths.
"The council has developed principles to ensure trees remain part of our future urban development and that public expectations about how they are managed are met."
Ms Bainbridge said the principles were part of the Street Tree Strategy which was developed collaboratively with the community.
The cost of removing and replacing a tree was about $4000 per tree, depending on the location of the tree and its impact on adjacent infrastructure.