Alternative approach: Screw parks.

Parks are not nature. Parks are a sanitized parody of the natural world. They are a simulation meant to make us humans feel better about ourselves. They are gated grass farms, not wild areas, useful only to a select few animals (nothing bigger than a raccoon). Creating a park inside a urban area diverts land from actual nature. So, rather than build parks inside cities, we should develop that land and make our cities smaller.

We don't have to go all 40k hive world. Rather, if parks are kept at the urban periphery and/or are connected to each other, then they can thrive as actual natural space. We have modern transport technology. We can bring the people to the park rather than construct a park near the people and thereby deprive Bambi and all his friends of yet another acre of true wilderness.