APPENDIX 3
Tree Protection Guidelines What is a Tree Protection Zone (TPZ)?
1
A Tree Protection Zone (TPZ) is the principal means of protecting trees on development sites or adjacent by using a barrier to protect the tree root and crown area. The TPZ should be calculated and identified before construction or site works start to ensure the tree remains safe and healthy. Tree Protection Zones are an industry-wide practice and are developed in accordance with the Australian Standard – Protection of Trees on development sites (AS 4970-2009).
Why do I need a TPZ?
2
Trees provide valuable environmental and social benefits to our urban environments. Inadequate development design, planning and supervision can have severe impacts on the long-term survival and protection of trees well after construction is completed.
Determining the TPZ
3
The radius of the TPZ is calculated for each tree by multiplying its calliper or Diameter at Breast Height (DBH) at 1.4m above ground (Figure 1) by 12. Figure 2 indicates the calculated TPZ of this specific street tree.
Figure 1
38
Figure 2
