Estimating the volume of a log on the ground
If a tree has been felled and the bark removed
it is relatively easy to measure log volume. However, there
are a number of different equations that may be used. Farmers
need to agree with sawmillers on one method before selling
logs to the mill. Log buyers may dictate that log volumes
be determined from centre diameters, small end diameters,
an average of the diameters at each end or from the average
cross sectional area at each end. Where the latter method
may be more accurate, the others are much quicker and may
better reflect log value.
The table below shows a number of commonly used
methods. Whilst Method 4 (the Smalian method) is generally
considered the most accurate, Method 3 (the Huber method),
based on the centre diameter, is more commonly used. Some
millers may prefer Method 1. If the bark is still on the log,
it must be accounted for when determining the diameters. This
can be done by judging bark thickness using a knife or debarking
the log at that point.
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