Online Calculator

This Calculator is developed from the Australian Standard AS4970-2009 and is provided as a downloadable tool for use by professional Arborists in determining tree protection zones (TPZ) and structural root zones (SRZ).

This calculator provides a table to determine the TPZ radius for single stemmed trees and second table for multi stemmed trees. A third table is provided to determine the SRZ radius. In all cases the tables indicate entries and outputs in cm or metres.
At the end of each calculation do not save changes. This will ensure the calculator values are clear ready for the next set of entries and data output is not corrupted.

Download the On-line tree calculator (xlsx)