chunktreefix

NeoForge 1.21.1 fix for MC-224729: trees, structures, and any other world-gen feature that overhangs from an already-generated chunk into a neighboring chunk that hasn't finished generating yet can get silently discarded when that neighbor chunk is saved — producing the "cut off at the chunk border" look on trees and structures.

This is a reimplementation (not a copy) of SuperCoder79's chunksavingfix-fabric (MIT, originally for 1.16.5 Fabric), rebuilt against current NeoForge 1.21.1 internals.

Status: Beta

Confirmed working in real play across a ~350-mod pack, alongside several other mods that also touch chunk saving/caching (ServerCore, SmoothChunk, ModernFix, Lithium). One known risk: this patches ChunkMap#saveChunkIfNeeded with @Overwrite. If another mod in your pack also overwrites that exact method, the two will conflict and the game won't start. Not yet tested on a dedicated server (only singleplayer/integrated server so far).

If your game fails to load with this installed, please open an issue on GitHub with your crash report and mod list.

Note on performance

This is a correctness/bugfix mod, not a performance mod — it adds a small amount of extra disk I/O for chunks that were previously (incorrectly) skipped during save, bounded by vanilla's existing per-chunk save cooldown.