In vanilla, leaves will not decay as long as they're attached to either a logblock or any instance of leavesblock, this mod changes it so that leaves will decay if their only attachment to a tree is through a different leaf type so chopping down a birch tree will decay all the birch leaves and not leave some attached to others such as oak.
Can run serverside only but still works in singleplayer.
Requires mixinbootstrap until forge decides to ship mixin: https://www.curseforge.com/minecraft/mc-mods/mixinbootstrap
Disclaimer: for the sake of brevity fastleafdecay was used to hasten the decaying of the leaves for demonstration, this mod does NOT speed up the decaying of leaves.)
Discord for chitchat and other things: https://discord.gg/vZxnfa4
Project members
tfarecnim