
Why measure Forest Measurement and Modelling. 


When you measure an object, essentially all you are doing is counting the number of standard pieces it takes to be the same size as the object. For example, the length of an Olympic swimming pool is 50 m, because 50 one metre standard lengths laid endtoend would be exactly the same length.
The same principle works when we deal with something that is too small to be conveniently handled by straight counting of standard pieces. For example, the heights of people or of trees are not usually an exact number of meters. So, we simply say that the standard meter is actually a group of smaller standard lengths  centimetres. Each centimetre can also be a group of still smaller objects  millimetres. So we can describe or measure anything simply by counting the number of standard or groups. We may define measurement as: the determination of size in relation to some observed standard, e.g. metre, kilogram, second, ampere, degree Kelvin, candela, mole, or some unit derived from these seven basic units. 

Why measure? 
Measurements are made for a number of reasons:

Standard units 
Australia, as a signatory to the Metric Convention, has made a commitment to use the International System of Units (SI for short). These units are precisely defined so that, for example, 1 metre in Australia can be exactly compared with 1 metre in Europe. The standard units are:
Other units can be derived through the inclusion of decimal prefixes (e.g. deci, kilo). Some units are not included in the SI, but are nevertheless commonly used and accepted:
Standards also extend to the way measurements are recorded. These standards include the way symbols are written and large and small numbers are reported. The Code of Forest Mensuration Practice (RWG#2, 1999) at http://www.anu.edu.au/Forestry/mensuration/rwg2/code/11.htm provides a detailed list of these standards for writing. Throughout history, many standards have been developed and used in measurement, including:

[measure.htm] Revision: 6/1999 