Leaf Decay Distance

Leaf Decay Distance lets leaves stay alive farther from a log before they decay.

In vanilla, leaves decay if they're more than 6 blocks from a log, but this mod raises that limit so big trees/custom trees keep their whole canopy while leaves still decay when the tree is cut down as well as adding corner checking. Basically it's intended to be a companion mod to custom maps so large custom trees can still be vanilla friendly.

Features

Configurable distance (7 to 32, default 16), editable in-game under Mods → Leaf Decay Distance → Config
Keeps vanilla behavior, just with a longer distance from the log
Works with modded leaves that use the vanilla leaf system
Adds a toggle (on by default) that allows diagonal and corner to corner connections to count as part of a tree (meant for palm trees and the like).

Important

Changes need a restart so the config takes effect the next time the game starts.
It's serverside so you need to install it on both the server and every player's game, with the same config value. If they don't match, you'll end up with ghostblocks in multiplayer.
Removing the mod from a world will cause leaves more than 6 blocks from a log to decay obviously, so just make sure no trees depend on it.

Pairs well with a fast leaf decay mod if you want big trees to clear quickly after chopping.