While walking with my children we saw two seperate trees being used as human refuse containers. The apple pictured here is thankfully biodegradable, but the garbage found in the other tree unfortunately was plastic and some paper that could have been recycled. The really odd thing about both trees was that garbage cans were visible from both tree.
Even more recently my kids dumped a couple apple cores at the base of the tree outside our house…but they put them out there as a snack for the Racoon that lives in a nest in that very tree. Had the Racoon not eaten the apples we would have cleaned them up.