All saw timber will be scaled by the Scribner Decimal log rule. This rule drops the units and gives the contents of a log to the nearest ten. When the total scale of a log is desired, all that is necessary is to add one cipher to the sum of the numbers read from the scale stick, excepting the contents of 6 and 8 foot logs, 6 and 7 inches in diameter. These are given as 0.5, which, multiplied by 10, gives 5 feet as the actual contents.

In the absence of a scale stick, or where the position of logs in the pile makes its use difficult, the diameters and lengths may be tallied and the contents figured from a scale table later.

Purchasers should be required to skid logs for scaling, if the cost of scaling will be materially decreased by these requirements and if the cost of logging will not be greatly increased.

The forest officer should always insist on having one end of piles or skidways even, so that ends of logs may be easily reached.

When necessary and possible, the purchaser will be required to mark top ends of logs to avoid question when they are scaled in the pile.

Each log scaled must be numbered with crayon. The number will be the same as that opposite which the scale of the log is recorded in the scale book.

The logs in all skidways must be counted, and the number in each checked with the entries in the scale book.

Each merchantable log after scaling will be stamped " U.S." on at least one end. Logs so defective as to be unmerchantable will not be stamped, but will be marked " cull."

On all national forests except those in Alaska and on the west slope of the Cascade Mountains in Washington and Oregon, logs over 16 feet long will be scaled as two or more logs, if possible in lengths not less than 12 feet.

The following table shows how the lengths will be divided when scaling logs 18 to 60 feet long. The number of inches to be added to the diameter at the small end of each log, to cover taper, is placed under each length.

For example, a 42-foot log 16 inches in diameter at the top would be scaled as —

One 12-foot log with a diameter of 16 inches.

One 14-foot log with a diameter of 17 inches.

One 16-foot log with a diameter of 19 inches.

Allowances for taper in logs

This table is intended to be used simply as a guide. The allowances for taper should be varied to conform to the actual taper

Total Length

Log Length

Total Length

Log Length

Feet

Butt Log

Second Log

Third Log

Top Log

Feet

Butt Log

Second Log

Third Log

Top Log

18.....

10'

   

8'

40 ... .

16'

12'

 

12'

Increase

1"

   

0"

Increase .

3"

1"

-----.

0"

20.....

10'

   

10'

42 ... .

16'

14'

 

12'

Increase

1"

-----

 

0"

Increase .

3"

1"

 

0"

22.....

12'

   

10'

44 ... .

16'

16'

 

12'

Increase

1"

   

0"

Increase .

3"

1"

 

0"

24.....

14'

   

10'

46 ... .

16'

16'

-----

14'

Increase

1"

   

0"

Increase .

4"

2"

-----

0"

26.....

14'

   

12'

48 ... .

16'

16'

 

16'

Increase

1"

   

0"

Increase .

4"

2"

 

0"

28.....

14'

 

-----

14'

50 ... .

14'

12'

12'

12'

Increase

2"

   

0"

Increase .

4"

3"

1"

0"

30.....

16'

   

14'

52 ... .

16'

12'

12'

12'

Increase

2"

   

0"

Increase .

4"

3"

1"

0"

32.....

16'

   

16'

54 ... .

16'

14'

12'

12'

Increase

2"

   

0"

Increase .

5"

3"

1"

0"

34.....

12'

12'

 

10'

56 ... .

16'

16'

12'

12'

Increase

3"

1"

 

0"

Increase .

5"

3"

1"

0"

36.....

12'

12'

 

12'

58 ... .

16'

16'

14'

12'

Increase

3"

1"

 

0"

Increase .

5"

3"

2"

0"

38.....

14'

12'

 

12'

60 ... .

16'

16'

14'

14'

Increase

3"

1"

 

0"

Increase .

5"

3"

2"

0"

Cubic Log Measure (The Woodsman's Handbook)

A cubic unit, either the cubic foot or cubic meter, ultimately will be in common use for the commercial measurement of timber. This will come about with the increase of the value of timber. When the whole log, including slabs, can be used, the owner cannot afford to sell his logs purely on a basis of an estimated product in manufactured boards. If logs are bought according to their solid contents, though they may not cost more, yet the buyer will feel that he pays for the material he wastes, and therefore will be more eager to utilize it.

There are a number of methods of determining the solid contents of logs in cubic feet. The two methods in most common use for commercial work are given in this book. Other methods, designed for scientific work, are discussed at length in treatises on forest mensuration.

Method of cubing logs by the measurement of the length and of the middle diameters.

To cube logs, one method requires the measurement of the average diameter of the log at its middle point and the length. The volume of the log is obtained by multiplying the area of the circle corresponding to the middle diameter of the log by the length: in which V is the volume of the log in cubic feet, B1/2 the area of the middle cross section in square feet, and L the length in feet.

Example: Suppose a log to have a middle diameter of 15 inches and a length of 30 feet. One finds in a table of areas of circles (giving the diameter in inches and the area in square feet) the area corresponding to 15 inches, namely, 1.227; then V = 1.227X30 = 36.8 cubic feet.