fix

src/world/generation/forestry.rs

@@ -253,7 +253,7 @@ pub fn generate_chunk_forrestry(
     }
 }
 
-/// Remove all fixture tiles and entities belonging to the tree rooted at `root_pos`.
+/// Fells the entire tree containing the trunk at `trunk_pos`.
 ///
 /// # How trees are identified
 /// Finds all TreePart entities whose XY is within canopy radius of the trunk column.
@@ -266,20 +266,25 @@ pub fn generate_chunk_forrestry(
 /// - Fires `TileChangedEvent` for path invalidation
 /// - Fires `TileOcclusionEvent` for the column at each removed position
 ///
+/// # chunk_entity_index
+/// Despawned tree entities leave stale entries in `chunk_entity_index`. This is harmless:
+/// `unload_chunk` calls `despawn()` on each indexed entity, which is a no-op on
+/// already-despawned entities.
+///
 /// # Performance
 /// O(tree_size) entity lookups via `Query<(Entity, &TreePart)>`. For a typical tree
 /// (4-8 trunk + ~60 leaf tiles) this is ~68 iterations. Acceptable for an infrequent
 /// action.
 pub fn fell_tree(
-    root_pos: IVec3,
+    trunk_pos: IVec3,
     tree_parts: &Query<(Entity, &TreePart)>,
     commands: &mut Commands,
     tilemap: &mut TileMap,
     tile_changed: &mut MessageWriter<TileChangedEvent>,
     occlusion: &mut MessageWriter<TileOcclusionEvent>,
 ) {
-    let trunk_x = root_pos.x;
-    let trunk_y = root_pos.y;
+    let trunk_x = trunk_pos.x;
+    let trunk_y = trunk_pos.y;
     let canopy_radius_world = (TREE_LEAF_BASE_RADIUS * TILE_SIZE) as i32 + ITILE_SIZE;
 
     let to_remove: Vec<(Entity, IVec3)> = tree_parts
@@ -298,6 +303,7 @@ pub fn fell_tree(
 
         // Full column occlusion refresh for each removed tile.
         // calculate_visibility traces up arbitrarily deep, so refresh the full column.
+        // TODO: batch into a dirty-region approach once tree felling is common (~13k events/tree).
         let z_depth =
             crate::world::chunks::Z_BELOW as i32 + crate::world::chunks::Z_ABOVE as i32 + 1;
         for dz in 0..=z_depth {