Hoppus Log Volume.

Australian foresters are lucky to no longer endure some of the older “head scratching” imperial measurements.

Hoppus Log Volume (HLV) was used around the British Empire and is still used in some countries.

Introduced in 1736 by English surveyor Edward Hoppus, it estimated the volume of a round log that would produce usable or merchantable timber after processing. This was in effect, attempting to “square” a “round” log.  

Round logs were measured at the midpoint for circumference (or girth) in inches and length in feet.

Hoppus Log Volume, in cubic feet, was calculated using one quarter of the girth, which was then squared and multiplied by the length of the log, with the total then divided by 144. This method slightly underestimated the volume of the log but did away with the using the pesky π.

• Hoppus Log Volume (cubic feet) = (Girth (inches) ÷ 4) ² x Length (feet) ÷ 144
• True Volume (round) = π x Radius ²  x Length.

The combined result of “squaring” a round log, as well as allowing for the quarter girth technique, meant that Hoppus Log Volume was 27.3% less than the “true”, or round, log volume. This was intended to allow for sawn waste.

One cubic foot hoppus is a lump of wood 1 foot wide by 1 foot long and 1 foot thick.

The Forests Commission traditionally measured and reported the production of sawn timber in super feet – which was short for superficial feet. Sometimes also known as a board foot it represented a piece of sawn timber 1 foot wide by 1 foot long and 1 inch thick. There are 12 inches in a foot, so one cubic foot equalled 12 super feet.

Round logs were measured and reported by the Forests Commission in Super Feet Hoppus Log Volume.  

• 100 Super Feet Hoppus Log Volume (SF HLV) = 0.301 cubic meters (true).

Confused… so were most people… but from 1 July 1974 all logs and sawn produce were thankfully measured in cubic metres (true volume).

However, in the United States and Canada, buying and selling logs as well as standing trees is still based on board feet.

There are also over 95 log scaling rules bearing about 185 names. However, only three, Doyle’s, Scribner, and International, are widely recognised and in current use, but they can vary across the country.

Fred Neumann measuring logs on Connors Plain north of Licola. Photo: Gregor Wallace – 1959.