Steps to Reproduce

1. Launch pure vanilla Minecraft Java Edition 26.3 Snapshot 8, no mods, no resource packs, no datapacks.

2. Create a new single-player world with default overworld generation rules.

3. Navigate to the new Dappled Forest autumn biome on hilly terrain.

4. Observe the autumn trees naturally spawned in this biome.

5. Press F3+F6 to show structure bounding boxes for extra inspection.

Actual Result

Natural trees in the Dappled Forest biome have broken trunk generation. The canopy leaves generate fully normally, but the vertical trunk only generates one single log block, the rest of the trunk fails to generate and cannot connect down to the ground. Besides, residual structure void blocks and structure blocks are left embedded inside the hillside terrain after world generation.

Expected Result

All Dappled Forest autumn trees should generate complete, continuous vertical log trunks connecting from the leaf canopy all the way down to the ground block. All temporary structure placeholder blocks should be removed automatically after generation.