Woodcraftsmen who made containers were called coopers, and the use of particular woods to suit each need was the cooper’s special art because each wood reacted differently, both in the crafting process and also to items that might be stored within. The wet cooper, also known as a tight cooper, made staved casks and barrels for all kinds of liquids; he was an expert with oak wood. The dry (or slack) cooper made barrels for sugar, flour, and meal. He was expert with maple, elm, and chestnut. The white cooper, who was expert with birch, beech, maple, and pine, made small tubs, butter churns, bowls, plates, and boxes. All these things were called “treenware” from the early plural of trees. John Sutter made reference to coopers 23 times, between 1845 and 1848, in the log book he kept for projects and events happening in and around his fort compound in the Sacramento Valley.