Cambrey: In the Dragon Quest series. I personally like what they did in DQ7.
Personally, I like Dragon Quest 4's tree. One nice thing is that, if someone dies while you're in that dungeon, you can just use a leaf to revive that character and just pick up another one.
Incidentally, the game only lets you have one leaf at a time; if you try to pick up another without using the first, the game will give an excuse to the effect that "the leaf didn't come off".
By the way, the whole "can only have one leaf at a time" is a recurring theme throughout the series (except DQ1, where the leaf, even if it existed, would be useless, as you only have one party member). The Dew from the tree, which fully heals the party, has sometimes had a similar restriction (it did in DQ4, its first appearance).
By the way, I remember one of the Kirby games having a tree as a boss; could anyone tell me which one?