.................Calculating Risk of Harm

When working in the field, manual calculation of probabilities is impractical. To facilitate field assessment, a calculator has been developed (opposite) comprising three vanes, which are rotated to select values from predetermined ranges of probability and calculate the product of the three component values. The calculator displays the result as an index (one thousandth of the reciprocal) of overall probability, which is termed the ‘Risk Index’ For example, if the risk of harm is 1/10,000, the Risk Index is 10 (10,000 ÷ 1000 = 10).

Alternatively, the probability ranges in a spreadsheet format can be loaded onto handheld data collection devices for use with tree inventory software.

With our associates at ARBORtrack Limited, we have developed software to calculate the Risk of Harm to an even greater degree of accuracy.