u/Beach6060

Help needed!
We are replacing an existing carport.
We have two gumtrees on our property. We already know one is a "significant" tree and the other is a "regulated" tree.
We do not want to touch the trees. We already know we can't.
There is an existing 15sqm shed between one of the trees and the existing carport. This shed is not being touched in any way.
Replacing the carport will not impact the trees in any way. The distance between the carport and tree is four meters.
Onkaparinga council is now asking for an arborists report for one of the trees.
I cannot see why they would want this, or what it will achieve or what information they could possibly gain.
Can anyone enlighten me?
Any help greatly appreciated.