SUPERSEDED - Reference Documents - MCU25 0079

6. Data Collection
All tree inspections are performed from ground level without detailed investigation unless otherwise noted
within the assessment. The method of inspection performed was a basic level 2 visual tree assessment
(VTA) as per ISA guidelines, ANSI A300 Standard for Risk assessment and ISA’s Best Management
Practices.

The arborist report includes the capture of trunk measurements Diameter at Breast Height (DBH), 1.5
meters from ground level and Diameter Above Basal Flare (DABF), to calculate the Tree Protection Zone
(TPZ) and SRZ for each tree assessed.

A Yamayo Million Diameter tape was used to capture these trunk diameters with the Treetec online
calculator used to calculate the TPZ radius.

A Useful Life Expectancy (ULE) rating has been provided based upon the health and structure of the tree
at time of inspection (Refer to Appendix 1 for a definition of ULE).

7. TPZ Measurements
TPZ and SRZ calculations have been formulated in accordance with AS 4970 Protection of trees on
development sites.

Determining the Tree Protection Zone (TPZ): (Extract from AS 4970: 2009) The radius of the TPZ is
calculated by multiplying its Diameter at Breast Height (DBH) x 12. TPZ = DBH x 12 DBH = trunk diameter
measured at 1.5 metres above ground. Radius is measured from the centre of the stem at ground level.

Determining the Structural Root Zone (SRZ): SRZ radius = (D x 50) 0.42 x 0.64 where D = trunk
diameter, in metres, measured above the root buttress or Diameter Above Basal Flare (DABF).




Arborist Report Impact Assessment – TSA: 5635.1 4 Ventura Street Sunrise Beach.
Treesafe Australia Pty Ltd. June 2025© *Refer to explanatory Notes.

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