6–1 When sawn, a log yields round timber, ties, or lumber of varying quality. This chapter presents a general discussion of grading, standards, and specifications for these commer-cial products. In a broad sense, commercial lumber is any lumber that is bought or sold in the normal channels of commerce. Com-mercial lumber may be found in a variety of forms, species, and types, and in various commercial establishments, both wholesale and retail. Most commercial lumber is graded by standardized rules that make purchasing more or less uni-form throughout the country. Round timbers and ties represent some of the most effi-cient uses of our forest resources. They require a minimum of processing between harvesting the tree and marketing the structural commodity. Poles and piles are debarked or peeled, seasoned, and often treated with preservative prior to use as structural members. Construction logs are usually shaped to facilitate construction. Ties, used for railroads, landscaping, and mining, are slab-cut to provide flat surfac-es. Because these products are relatively economical to pro-duce compared with glulam, steel, and concrete products, they are commonly used throughout the United States. To enable users to buy the quality that best suits their pur-poses, lumber, round timbers, and ties are graded into use categories, each having an appropriate range in quality. Generally, the grade of a piece of wood is based on the num-ber, character, and location of features that may lower its strength, durability, or utility value. Among the more com-mon visual features are knots, checks, pitch pockets, shake, and stain, some of which are a natural part of the tree. Some grades are free or practically free from these features. Other grades, which constitute the great bulk of solid wood prod-ucts, contain fairly numerous knots and other features. With proper grading, lumber containing these features is entirely satisfactory for many uses. The grading operation for most solid wood products takes place at the sawmill. Establishment of grading procedures is largely the responsibility of manufacturers' associations. Be-cause of the wide variety of wood species, industrial practic-es, and customer needs, different grading practices coexist. The grading practices of most interest are considered in the sections that follow, under the major categories of hardwood lumber and softwood lumber, round timbers, and ties.