The word ‘leaf’ may refer to a part of a plant or tree or even a door, It refers to a ‘blade’ of the item. It depends on how you use the word. If it is used as a proper noun then of course, grammatical rules are sometimes thrown to the wind. An example is the name of the Canadian Hockey Team “The Toronto Maple Leafs”.
https://www.quora.com/What-is-the-plural-of-leaf-Is-it-leafs-or-leaves

