A petition is not likely to be an accurate or reliable source of information.

I would say there's a good chance the tree would be removed and no bike lane is even installed.

You really just pulled this out of your arse.

They also say there is a strong wildlife population, and asks if the government has done a wild life study. It seems like they havent. So they dont know what the real costs are to the local environment. They are deliberately not seeking answers to questions they dont like.

What is a "strong" wildlife population? The way that EIAs prescribed by the legislation determine whether impacts on wildlife are significant or not is by looking at the risk of localised or general extinction and/or reduction in population numbers of species and communities listed as threatened, or otherwise established as being of high conservation value. Reducing habitat availability to Miners, Mynas, Currawongs, Bulbuls, Starlings, Sparrows, Maggies etc. would not a sufficient impact to trigger protective measures. If you disagree with that stance then get yourself an ecological education or go lobby your State MP. So no, a wildlife study would not have been required for this project, and we can be very confident that it would not have been required because people like myself, who have a strong interest and some level of expertise, have walked down that street thousands of times and if we'd have ever spotted anything of any conservation value then the Council would have known about it. If this bike path were proposed for a location 800km west then there would be less confidence in the accuracy of the available records and an species survey would be warranted.

All in all, there is a good argument that no bike lane is even needed, and that the 'replacement' tree would be inadequate for the local conditions.

Based on what? A sign and a petition you read?