Mainly small shot, What does concern me is when you see feeders and sometimes floats in trees or foliage on an island, The angler must have pulled for a break, and depending where the line breaks there will be at least enough line to entangle birds,
also the hook will more than likely be baited, another hazard for wildlife, I have seen this on various waters, If you are going to cast to island with trees on them, have a few casts short, and pull line off the spool and keep casting until you are close enough without landing on it, Then clip up, Don't chuck it and chance it,or if not confident don't do it, As for getting stuck in trees above you, the mind boggles. Either try a side cast or change swims if not confident, I have seen waters closed to anglers due to the amount of tackle left in trees and on islands, this has been a major contributor along with litter.