How is wood logs measured?

Our team receives several questions about the use of different wood measuring formulas around the world. From Argentina to Myanmar, from the JAS Scale to the Imperial Hoppus, we are always ready to help our community find the best solutions, be it the work done with eucalyptus or pine, be it the measurement done in the metric or imperial system, either for the sale, purchase or quality control of your batteries.

In the Timbeter, by bringing solutions and making measurements easier and more precise, we make the industry more sustainable and profitable for all. Inevitably, we understand that the world is changing – and that is why we need to make everyone better around us.

Within our application, there are 11 wooden measurement formulas and tables popular in measurements worldwide, according to different regions, industries and specific requirements of some companies. Below, you can find the 11 formulas and tables, briefly explained:

  • Cylindrical Formula
  • JAS scale
  • GOST 2708-75
  • Doyle Toyle Scale
  • International Rule 1/4 “
  • Toras Roy’s Rule
  • Scribner Rule Decimal C
  • Measurement Rule Ontario
  • Nilson (Estonian Formula)
  • Lithuanian formula
  • Hoppus
  • Cylindrical Formula

The Cylindrical Formula is the most direct wooden measuring formula and used for fast measurements. This does not mean that the method is the most accurate and should not be used on all types of logs due to its unique structures and the fact that wood is a valuable material. The Cylindrical formula is the most widely used method for measuring pulpwood and firewood and is the most conventional method used in Central Europe.

Formula:
V = π x r² xh

JAS scale
The Japanese Standard Agricultural Scale was developed to measure logs in the late 1940s and became popular in East Asia, Oceania (including Australia) and Chile. It is used especially by companies that export logs of wood to China and Japan.

Formula:
For trunks less than 6 meters in length:
V (m3) = (D² * L) / 10000
where:
D – diameter of the lower end (cm), less than 14 cm, the diameter is rounded down and more than 14 cm, the diameter is rounded down to the nearest even number.
L – Length (m)

For trunks equal to or greater than 6m:
V (m3) = (D + [L’-4] / 2) ^ 2 * (L / 10000)
where:
D – diameter of the lower end (cm), less than 14 cm, the diameter is rounded down and more than 14 cm, the diameter is rounded down to the nearest even number.
L – Length (m)
L ‘- Length in meters rounded down to the nearest whole number

GOST 2708-75
The GOST 2708-75 interstate standard, called “Rounded bulls. “Table of volumes” was a table implemented by the Soviet government in 1977, in which the standard volume of a trunk is determined by the thickness of the upper end and by the length of the trunks. This table is commonly used in Russia and in some countries of the Commonwealth of Independent States as synonymous with quality for measuring timber logs.

Doyle Trunks Rule
The Toyle Doyle Rule is used in the East and Central parts of North America, being originated in 1825. Unlike the Scribner rule, Doyle is based on a formula.

Formula:
bf volume = (diameter of the lower end in inches – 4) ² x length / 16
bf means board foot = at the beginning it represents a piece of wood that normally measures 1 “x 1″ x 1 ‘, but in reality it represents volumes and/or dimensions that are significantly different depending on the product being measured.

International Rule 1/4 ”
This rule was published in 1917 and was used primarily in the eastern part of North America, being especially popular in the regions of Quebec and New England. In addition, it was adopted by the United States Forest Service in several regions.

Formula:
V = (0.199 x diameter in inches²) – (0.642 x diameter in inch);
where:
V = volume in board feet for 4-foot sections
D = dib at the lower end for 4-foot lengths

Troncos Roy Rule
This formula is used in the province of Quebec, Canada. It is very accurate for trunks of 14 and 16 feet.

Formula:
BF = (d – 1) ² L / 20
where:
BF = board feet
d = diameter measured in inches inside the bark at the lower end of the tora
L = length of the Tora in feet

Scribner Decimal C
The Scribner Decimal C is used in the Midwest and North of North America, which was published in 1945 by the University of Minnesota and uses the help of a table.

Formula:
(0.79 * D² – 2D – 4) * L / 16 = FBM rounded to the nearest 10 FBM (313 ~ 310, 317 ~ 320, etc.)
D – diameter of the lower end in inches, rounded down if the diameter is exactly.5
L – Length in feet

Measurement Rule Ontario
Used in sawmills in the province of Ontario, Canada, it was adopted as the official rule in 1952.

Formula:
BF = (0.55D² – 1.2D) * L / 12
where:
BF = board feet
D = Diameter measured in inches inside the cortex through the lower end of the trunk
L = trunk length in feet

Lithuanian
The system used in this Baltic country is based on a Table of Volume of Logs, which represents the norms of the 8 main tree species of the country (pine, fir, birch, poplar, black alder, gray, oak and stacked). The measurements can include or exclude the shell.

Nilson
Estonians use the formula developed by Arthur Nilson to calculate the volume of wood logs. This method uses a formula and a support table with coefficients, depending on the type of tree.

Formula:
cbm = (d² * L * (a1 + a2 * L) + a3 * L²) / 10 000
d – diameter of the lower end
L – length dm
a1, a2, a3 – Coefficients defined by tree species.
For pine a1 = 0.0799, a2 = 0.000146, a3 = 0.0411
For fir a1 = 0.07995, a2 = 0.00016105, a3 = 0.04948
For fir and other hardwoods a1 = 0.0783, a2 = 0.000236, a3 = 0.045
For other conifers a1 = 0.0800, a2 = 0.000154, a3 = 0.0453

Hoppus
This ancient measuring system was in use in the United Kingdom and in the former British colonies. It became popular in 1736 and is still used in Asia, Africa, South America and Oceania. It can be used in both the metric and imperial systems.

Formulas:
Imperial:
Hoppus ft³ via circumference = (average circumference in inches / 4) ² x length in feet / 144
NB! Round to the nearest 10 ft³

Hoppus ft³ via diameter = average diameter in inches² x length in feet x 0.004283
NB! Round to the nearest 10 ft³

Hoppus superficial foot = Hoppus ft³ x 12

Hoppus ton = hoppus ft³ / 50

Metrics:
Hoppus m³ via circumference = (average circumference in cm / 4) ² x length in meters / 10,000
NB! Round the next three decimals

Hoppus m³ via diameter = average diameter in cm² x length in meters x 0.000061685
NB! Round the next three decimals

Leave a Reply

Your email address will not be published. Required fields are marked *