Plating trees in your garden is always a recipe for future disputes with your neighbours, as petty as it sounds people get really uppity about keeping your shrubbery out of their view and boundaries. But that also depends where you live, I've seen a lot of trees cut down in my city over the past few years because they are a "nuisance". It's more likely that the city council just gave up on keeping them maintained or gave in on 1 or 2 complaints. Some of these trees were oaks that were most likely hundreds of years old and this is in public parks not close to any properties.

They are also trimmed down which is not as bad but not really helping the problem mentioned. Again these trees were hundreds of years old.

https://i2-prod.leicestermercury.co.uk/incoming/article16420...

Planting trees in public spaces seems like a recipe for the council just taking them down. I'm not sure if it's even allowed by law.

Seeking permission from land owners would be a pain. For one they could just say no, which is fair because it's their land. But how do you go about finding out who they are in the first place?