[Illustration: Figure 62. A big Sugar pine tree about six feet in diameter. This is the most valuable timber species in California. Photo by the author.] [Illustration: Figure 63. A Western Yellow pine forest in California. These trees are from four to six feet in diameter and from 150 to 200 feet high. Note the Forest Service timber cruiser measuring the tree at the left. Photo by the author.] All saw timber is scaled by the Scribner Decimal C log rule. In order to permit scaling at reasonable cost to the Forest Service, purchasers may be required, where the cost of logging may not be unduly increased, to skid and pile the logs for scaling. Piles and skidways must be constructed so as to permit economical scaling and when necessary and practicable the purchaser is required to mark the small ends of the logs to avoid misunderstanding when they are scaled on the pile. Logs or other material that has been scaled or measured are designated by a "US" stamp impressed in the wood so that the material may not be scaled again by mistake. Each merchantable log scaled is stamped on at least one end and unmerchantable or defective logs are stamped "US" in a circle. Material other than saw logs, such as mine timber, ties, posts, poles, or piling, after scaling, is stamped on at least one end. Cord wood is stamped at both the top and bottom of each rick. On all National Forests except those in Alaska and west of the summit of the Cascades in Washington and Oregon, logs over 16 feet are scaled as two or more logs as far as practicable in lengths of not less than 12 feet. In Alaska and parts of Oregon and Washington logs up to and including 32 feet in length are scaled as one log; logs from 32 to 64 feet inclusive are scaled as two logs as nearly equal in length as possible in even feet. All diameters are measured inside the bark at the top end of the log and diameters are rounded off to the nearest inch above or below the actual diameter. In the case of logs each one is numbered and the number entered in a scale book with the corresponding board foot scale of the log. In the case of ties, posts, poles, mining timbers, etc., each pile or skidway is numbered and the count or scale entered opposite the corresponding number in the scale book. _Disposal of Slash._ One of the most important features in National Forest timber sales is the disposal of the brush or slash after logging. On account of the great diversity of conditions which obtain on the Forests, the best way to dispose of brush is not everywhere the same. Piling and burning is required where the fire risk is great; otherwise the method promising the best silvicultural results is used. [Illustration: Figure 64. Logging in California. Powerful steam engines pull the logs from the woods to the railroad and load them on flat cars. Photo by the author.]