I generally find that frum families are aware of the need to pick up after themselves in park settings. The few times I’ve seen flagrant disregard for leaving trash behind/ littering are in the context of large families with very young children who likely are NOT regular park visitors (outside of local city parks) and are just overwhelmed with keeping track of the kids, etc. Most respond positively (and with some embarrassment) when someone points out the mess they were about to leave behind. I don’t think its a cultural disregard for nature or an arrogance that since they don’t plan to be back the next day or week, “who cares”. I do wish more yeshivos would find some opportunity to encourage environmental awareness and personal responsibility in the daily lives of their talmidim to be good stewards of (in the words of the OP) “the beautiful nature of Hashem”.
