Q: Will any changes to settings work for an existing save?
A: Forests correctly spawn according to settings on a new save as well as on any newly generated chunk. Overlapping collision boxes due to updated values won't cause any crashes. As of v1.3.0, forests generate as intended no matter the settings, meaning that proper distance and density are preserved no matter the size of the collision box.

Q: Are you going to make any changes to the mod?
A: I were able to improve the mod in v1.3.0, but there might still be a few things I want to tweak. In particular, it would be great if I could somehow modify the collision box size of planted trees without changing the density at which they can be planted. Currently however, it seems to be an unsolvable problem.