--- a/net/minecraft/world/level/chunk/BiomeStorage.java
+++ b/net/minecraft/world/level/chunk/BiomeStorage.java
@@ -109,4 +109,14 @@
 
         return this.biomes[i1 << BiomeStorage.WIDTH_BITS + BiomeStorage.WIDTH_BITS | j1 << BiomeStorage.WIDTH_BITS | l];
     }
+
+    // CraftBukkit start
+    public void setBiome(int i, int j, int k, BiomeBase biome) {
+        int l = i & BiomeStorage.HORIZONTAL_MASK;
+        int i1 = MathHelper.clamp(j - this.quartMinY, 0, this.quartHeight);
+        int j1 = k & BiomeStorage.HORIZONTAL_MASK;
+
+        this.biomes[i1 << BiomeStorage.WIDTH_BITS + BiomeStorage.WIDTH_BITS | j1 << BiomeStorage.WIDTH_BITS | l] = biome;
+    }
+    // CraftBukkit end
 }