IkkatsuHakai Axe Mod Guide
Using the IkkatsuHakai Axe Mod
This mod expands what an axe can do. When you break a block that an axe can normally destroy, the mod also removes blocks in a wider area around it. By default, the blocks above the broken block are destroyed too, which makes felling trees much faster.
If you want to clear a tree all the way down, set DestroyUnder to true in the config file. That extends destruction to the root level instead of only upward.
The feature can be toggled on and off with a keybind, which is C by default. You can change this key in Minecraft's controls settings.
Everything is customizable through the config file. You can choose which axes are allowed to use the wider destruction and which blocks are affected by it. Config changes apply instantly, so you do not need to restart the game after editing them.