Attachment D - Tree Management Plan

                                                                                            2


Noosa Council has expressed some concern as to the effect of these works on existing well
established Park trees and requires a written methodology from a qualified arborist to
ensure a minimisation of harm.

For this purpose the author – a Level 5 consulting arborist with some 44 years’ professional
experience – attended the site on the 11th June 2019 in company with the site manager to
confirm the extent of works.

The Tree Management Plan (TMP) which follows will primarily follow the recommendations
of the documents Australian Standards AS4970-2009 Protection of trees on development
sites and AS4373-2007 Pruning of amenity trees.



2.0 Australian Standard AS4970-2009

This Standard (Protection of trees on development sites) defines Tree Protection Zones
(TPZ’s) and Structural Root Zones (SRZ’s) of trees according to their diameter. While the
meaning of the SRZ is self-explanatory, the TPZ is defined as ‘an area isolated from
construction disturbance, so that the tree remains viable’.

The TPZ is determined as a radius by multiplying its diameter (measured at 1.4 metres
height) by 12 i.e.
                          TPZ radius = 12 x DBH (diameter at breast height)

For multiple stems the DBH is determined by the following equation –

                              Total DBH = √(DBH 1)² + (DBH 2)² +………

In general a TPZ is not to be encroached by more than 10% and then only under the
supervision of an appropriately qualified arborist, with compensatory measures to be
implemented. Encroachment exceeding 10% may be acceptable but only under the
supervision of the arborist.

Typical compensatory measures include watering and the use of mulch.

The SRZ is contained within the TPZ and is the area required for tree stability and is
illustrated on page 13 of the Australian Standard or numerically by the formula –

                 Radius = (50 x D)* x 0.64
                 Where D = Diameter of stem and * = 0.42

Note that the TPZ calculation is of necessity somewhat arbitrary and reinforces the necessity
for obtaining advice from the site arborist.




Taylor Ecology                  Tree Management Plan – June 2019           Sunshine Beach SLSC