Response to information request REC13/0095

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      As  specified in the AS 4970-2009 Protection of trees on development sites, the tree
      protection zone (TPZ)is the principal means of protecting trees on development site. The
      TPZ is a combination of the root area and crown area requiring protection. This area should
       be isolated from construction disturbance so that the tree can remain viable.               The TPZ
      incorporates the structural root zone (SRZ).

      The radius of the TPZ is calculated for each tree by multiplying its DBH (Diameter at breast
      height   -
                   trunk diameter at 1.4m above ground) x 12


      Example: .5 m DBH x 12            =    6m Tree protection zone (TPZ)


      A TPZ should not be less than 2m or greater than 15m (unless crown protection is required).


                           7.1.2 SRZ

      Structural root zone, as specified in AS 4970-2009 Protection of trees on development sites,
      is the surface area of protection.required to maintain tree stability   -
                                                                                  a   larger area is required
      to maintain     a    viable.   It is only necessary to calculate the SRZ when    major encroachment
      into a TPZ is proposed.


      An indicative SRZ radius can be determined from the trunk diameter 0 measured in metres

      (above the root buttress) and applying the following formula:
                                     0.42
                           (0x 50)          x 0.64
               RSRZ    =




      The SRZ for trees with a trunk diameter less than 0.15m will be 1.5m.




               7.2 Tree Protection Fencing (TPF)


      Once the TPZ measurements and construction requirements have been calculated for the
      trees to be retained the alignment of the TPF may be determined. The TPF is required to be
      installed in the presence of TREE FIX prior to any construction works commencing on the
      site and for it to stay intact until completion of all works.


      Any tree removal or pruning within the TPZ could be carried out prior to the TPF being
      installed. These works are to be supervised and recorded by Consult Arborist Pty Ltd.


      When     specified in the Arborist Report the TPZ area will be mulched with com posted tree
      wood chips to an approximate depth of 100mm prior to fence installation. An additional Plant
      Health Care Program and/or temporary irrigation may also be specified.


      The TPF is to be steel mesh     panels (As detailed in AS4687-2007 Temporary fencing and
      hoardings) and held in place with concrete feet, the nut and bolt holding the clamps are to be
      tightened with a spanner to prevent the fence from being easily moved and secured to
      restrict access to those with permission only. Shade cloth or something similar can be
      attached to the fence to protect the area from airborne matter. Uneven ground and or
      exposed sites may require additional staking to hold the fencing in place. Care is to be taken
      when installing the additional bracing not to damage tree roots or hit underground services.


      Where the use of steel mesh   panels (As detailed in AS4687-2007 Temporary fencing and
      hoardings) is deemed not suitable for the site, the TPF can be constructed from orange site



      Tree F- x r PMP~130610            Callaghan & Toth Lake MacDona’d Drive Cooroy       Page 45 of 49