Hmm, would an automatic leveling (and tree removal) for buildings be desired in all cases?
Probably not the levelling, because I see a lot of cases where it could create problems (buildings models with extended underground walls, large structures, conflict with other roads in some areas...). Plus it shouldn't be applied to all objects, and there is no real difference between simple static models and buildings outside the keywords in metadata.
But right now it's the only way to remove trees, right?
One solution would be to remove (or hide) any trees inside the bounding box of a static object, but I have no idea if it's possible.