The cubic foot is the best unit for measuring the volume of logs. It has gained a foothold in this country, and will unquestionably be the unit of the future. Even now, red-cedar pencil-wood, wagon stock, and other valuable hardwood material is occasionally sold by the cubic foot in certain sections of the East. The unit is used by a few companies in Maine for measuring pulp-wood. A special commission on the measurement of logs has recently recommended to the legislature of Maine that the cubic foot be adopted as a statute unit of measurement.

The cubic foot has for a long time been used for the measurement of square timber. Round logs are often measured in terms of cubic feet, but the plan is to determine the contents of the square which can be cut from the log, rather than the full contents, including slabs. The cubic foot is in common use in the measurement of precious woods which are imported from the tropics.

In continental Europe and the Philippine Islands, the cubic meter has been established as the standard unit for the measuring of logs and timber.

In recent years, board measure has also been used as a unit of volume for logs. When so applied, the measure does not show the entire content of the log, but the quantity of lumber which, it is estimated, may be manufactured from it. The number of board feet in any given log is determined from a table that shows the estimated number which can be taken out from logs of different diameters and lengths. Such a table is called a log scale or log rule, and is compiled by reducing the dimensions of perfect logs of different sizes, to allow for waste in manufacture, and then calculating the number of inch boards which remain in the log.

The amount of lumber that can be cut from logs of a given size is not uniform, because the factors which determine the amount of waste vary under different circumstances, such as the thickness of the saw, the thickness of the boards, the width of the smallest board which may be utilized, the skill of the sawyer, the efficiency of the machinery, the defects in the log, the amount of taper, and the shrinkage. This lack of uniformity has led to wide differences of opinion as to how log rules should be constructed. There have been many attempts to devise a log rule which can be used as a standard, but none of them will meet all conditions. The rules in existence have been so unsatisfactory that constant attempts have been made to improve upon them. As a result there are now actually in use in the United States 40 or 50 different log rules, whose results differ in some cases as much as 120 per cent for 20-inch to 30-inch logs and 600 per cent for 6-inch logs. Some of these are constructed from mathematical formulae; some by preparing diagrams that represent the top of a log and then determining the amount of waste in sawdust and slabs; some are based on actual averages of logs cut at the mill; while still others are the result of making corrections in an existing rule to meet special local conditions.

The large number of log rules, the differences in their values, and the variation in the methods of their application have led to much confusion and inconvenience. Efforts to reach an agreement among lumbermen on a single standard log rule have failed so far. A number of states have given official sanction to specific rules; but this has only added to the confusion, because the states have not chosen the same rule, so there are six different state log rules, and, in addition, three different official log rules in Canada. It is probable that a standard method of measuring logs will not be worked out satisfactorily until a single unit of volume, like the cubic foot, is adopted for the measurement of logs.

The Forest Service of the United States Department of Agriculture has adopted the Scribner Decimal Rule for timber sales on the National Forests. It has been in use for about four years, and, in the main, has proved satisfactory, since competitive bids enable the buyer to bid higher if the character of the logs indicates a mill overrun.