How to make leaves that work similarly to vanilla?

So I wanna know how to make my custom leaves that drops itself when you use a shear, and when you break a naturally generating leaf block it'll have a chance to drop it's sapling and some sticks but it's not guaranteed, and when they aren't naturally generated they won't drop anything (when using your hand). The main problem is the natural leaves having loot tables and the manually placed ones not since while I could give the leaves in tree structures loot tables, but since the trees in the custom dimension aren't custom structures they can't work the same way. Anyone know how to make leaves act similar to vanilla?