Produces tree trunks out of 2 unprocessed wood. Necessary to make arrows for arrow towers.
- You should keep these 2-3 levels lower than your base.
- Only upgrade them if you see your supply is full but need more arrows.
- Keeping them the same level as your other industry helps keep resources filled.
- These are a low priority for upgrading. You should only upgrade these if your arrow supply is running low.
- Keep them 1-2 levels higher than your Harvesters.
- don't forget to upgrade steel factories to the same level, to keep arrow production steady.
- Put these and steel factories near the arrow factory as you get the same amount of sawmills, steel factories, and arrow factories in one level. (To boost production)
 original reference