What type of tree frogs are poisonus?

Well mainly the Poison Dart frogs. There could also be others but this is the only one I am sure of, usually the easiest way to tell if a creature such as this is poisonous is to look at it's coloring. The brighter and more vibrant the pigmentation the more likely it is poisonous... or colored to make you think it is. And yes, poison dart frogs do live in trees.