We still treat wood with oil. Your local home improvement store should stock a bunch and you’ll find more at a woodworking store. You can also add a sealant on

We still treat wood with oil. Your local home improvement store should stock a bunch and you’ll find more at a woodworking store. You can also add a sealant on top like polyutherane if you want it to last even longer at the cost of imparting a different texture.