The bark of chestnut oak has long been valuable for tanning. There is tannin in the bark of all oaks, and several of them contain it in paying quantities, but chestnut oak is more important to the leather industry than any other oak. In richness of tannin the tanbark oak of California occupies as high a place, but it is not supplying as much material as the eastern tree. Statistics showing the annual consumption of tanbark and tanning extracts in the United States, do not list the oaks separately, but it is well known that chestnut oak far surpasses all others in output. Hemlock bark is peeled in large quantities, but tanneries occasionally mix chestnut oak bark with it to lighten the deep red color imparted to leather when hemlock bark is the sole material employed. Large quantities of chestnut oak timber have been destroyed to procure the bark. Fortunately, it is a practice not much indulged in at present, because the wood now has value, but it formerly had little. It was then abandoned in the forest after the bark was peeled and hauled away. The same practice obtained with hemlock years ago. Much chestnut oak is still cut primarily for the bark, but the logs are worth hauling to sawmills, unless in remote districts. The chestnut oak is a vigorous tree and grows rapidly in dry soil, where it often forms a great part of the forest. It is not as large as the white oak or red oak, but is a splendid tree, its bole being very symmetrical and holding its size well. It grows usually to a height of from sixty to seventy feet and sometimes 100 feet, with a diameter of from two to five feet and occasionally as large as seven feet. The form of the tree shows great variation, depending upon the situation in which it grows. Trees in open ground often divide into forks or large limbs, and the trunks are short and of poor form. Open-grown trees show a decided tendency to develop crooked boles, and unduly large branches. No such objection can be urged against it when it grows under forest conditions. Trunks are straight and are otherwise of good form. The wood of chestnut oak differs little from that of white oak in weight, strength, and stiffness. It is hard, rather tough, durable in contact with the soil, and is darker in color than white oak. It has few large, open pores, and requires less filler in finishing than most oaks. There are many pores, however, and those in the springwood are arranged in bands. The summerwood is broad and distinct, usually constituting three-fourths of the annual ring. The medullary rays are as broad and numerous as in the best furniture oaks. They are regularly arranged, and spaces between them do not vary much in width. The wood quarter-saws well. The wood has the fault of checking badly in seasoning, unless carefully attended to. In recent years, these difficulties have been largely overcome, both in air seasoning and in the drykiln.