If you see an island of with no tree probably it is an type of survival island seed. That actually is an hard challenge because no tree, that mean you can’t create any tools or anything. But if you dig down and find some cobblestone and craft some pickaxes. Luckily have some animal on the island but mostly is chickens. Don’t eating them so soon, you need an plan to using resource because this is type of survival challenge seed. Also have a small island nearby with lot of sugar canes on the shore. That can be using create paper or food. Good Luck !!!
Seeds : 1419964984 Work in PE ver0.10.0+ or ver0.10.5