Remember that different tree types have different color wood. Make sure you use the same type of wood when building your treehouse trunk. Try building your treehouse near a forest or jungle so that you have an abundance of wood nearby.
You can also try building a treehouse out of an existing tree. Just clear the leaves around the trunk so you can build near the top.
If you are building a large tree trunk that is hollow on the inside, you can put the ladder inside the tree trunk. Just be sure to leave an opening with a door at the base of the tree trunk so you can enter. Alternatively, you can craft stairs and build a spiral staircase around the outside or inside of the trunk, instead of ladders.
Place a trapdoor above the ladder so you have a closable entrance to your treehouse.
When building at tall heights, be careful not to fall. Use sneak mode to walk slower.
