I didn't read the post sorry, just the title. I didn't see it was related to crime, I thought you were asking generally speaking. I can't talk about decreasing crime as Gary has a pretty bad reputation for it, but I'd be surprised if there wasn't a correlation between greenery (nature, trees, plants, flowers, etc) and crime, even if there wasn't any, I know being surrounded by nature is good for us/mental wellbeing.