Comparison of different log scaling formulas

, Co-founder and CTO of Timbeter.

We’ve already talked about different measurement formulas in one of the blog-posts earlier. There is a wide variety of log scaling methods around the world. Most of them utilize length and diameter information to determine volume in cubic units. Many log-scaling methods require small-end diameter measurement.
We often get questions about the difference between formulas.

Here is a comparison of the results that different formulas give

This is an example of volume calculation using unbiased rounding logic and two different formulas (Smalian and Huber).

In Timbeter you can find Cylindrical formula, Doyle log rule (US), Estonian (A.Nilson) formula, Russia’s GOST 2708-75 table and the Japanese Agricultural Standard formula.

All of the before-mentioned formulas (except cylindrical) use small-end diameter and log length for the determination of volume. In the future updates we will be implementing more formulas.

Differences in measurement results

Next graph will give a clearer view of the differences based on the results of FOREST PRODUCT CONVERSION FACTORS FOR THE UNECE REGION , GENEVA TIMBER AND FOREST DISCUSSION PAPER 49, published by UNECE/FAO and Timbeter implemented formulas.

For a single log you can get a volume difference of almost 4.9 times (Finland vs US Doyle log rule). It is worth noting that Doyle log rule is meant for calculating the log’s timber capacity.

Comparison of 100 logs

The following example will compare Timbeter’s formulas with a log stack of 100 logs (Birch, 3.2 m long). In the picture we have the small-end diameters facing towards the smart-device.

Graph to compare the differences in volume:

As a conclusion one may say that different formulas vary from each other quite a lot. Trading timber in different markets demands experience.

With the help of Timbeter it is easier and more transparent, as you can calculate one measurement with different formulas.

Get started with Timbeter, Download Timbeter application here!

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