A Dry Board is created by building a Timber Pile and letting it dry for 133 hours(5 Days, 13 Hours). Dry boards can then be taken from the Timber Pile. If not placed properly (At east 5 tiles away from any other object, except Tilled Fields), Timber Piles will give Moldy Boards rather than Dry Boards.
Dry Boards can be used to create Planed Boards, or Wood Choppings, at a Carpenter's Bench. Planed Boards are given if the action is successful, and 2 Wood Choppings are given otherwise. The success rate is based on the character's Hammer and Nail Proficiency.