Approved Plans and Documents - OPW22/0303

                                                                                                 Consult Arborist

A PPENDIX 1 - D EFINITION OF T ER MS
The following criteria have been used in the VTA and arboricultural appraisal to gather information and determine
the required management options on the grounds of public health and safety. Measurements are approximate,
made visually by eye unless otherwise stated.

 Age Class:
 Young:              Early-stage of growth, immature size
 Early Mature:       Fast-growing well-established tree which has not yet reached mature size
 Mature:             The tree reached its mature size, exhibits slowing growth rates with early stages of naturally
                     forming dead or dysfunctional wood.
 Over Mature:        Tree has reached mature size and is unlike to increase significantly in height or mass.
                     Retrenchment of the upper crown with increased vegetative vitality in lower crown, increased
                     fungal activity and wood decay, increase colonisation by flora and fauna.
 Veteran:            Tree with advanced retrenchment, reduced crown size and annual increment growth,
                     extensive hollowing, crown collapse, low vigour, advanced heartwood decay, advanced
                     colonisation by fauna and flora.
 Health:
 Good:               Tree with no defects or disorders which are notable. Full canopy with good colour foliage.
                     Minimal pathogen damage.
 Fair:               Tree with minor defects or disorders which are notable. Some dead wood within what can be
                     an unbalanced canopy, foliage generally with good colour although some discolouration may
                     be present typical of species in location. Minor pathogen damage.
 Poor:               Tree with major defects or disorders which are notable. Tree has considerable deadwood
                     present, discoloured or distorted leaves indicating a further decline of the tree. Detrimental
                     pathogen damage.
 Dead:               Dead or dysfunctional moribund tree.
 Structure:
 Good:             Tree with good unions and no branch defects. Sound trunk with no / minor defects. Good
                   buttress and root structure.
 Fair:             Tree with minor defects or disorders which are notable. Small areas of bark missing. Small
                   cavities or minor unfavourable branch unions may be present. Minor damage to roots.
 Poor:             Tree with major defects, large hollows, weak unions and/or problematic damaged roots.
 Hazardous:        This implies a tree with a major defect that may fail at any time
 Protection of Trees:
 TPZ:              Diameter at Breast Height - The approximate diameter of the trunk is measured visually in
                   millimetres at a height of 1.4m.
 SRZ:              The Tree Protection Zone, as per AS 4970-2009 Protection of trees on development sites, is
                   the principal means of protecting trees on a development site. The TPZ is a combination of
                   the root and crown area requiring protection to be isolated from construction disturbance so
                   that the tree can remain in a viable condition. The TPZ incorporates the Structural Root Zone
                   (SRZ).
                   The radius of the TPZ = DBH x 12
                   A TPZ should not be less than 2m or greater than 15m (unless crown protection is required).
 DBH:              The Structural Root Zone, as per AS 4970-2009 Protection of trees on development sites, is
                   a mathematical calculation of the surface area of protection required to maintain a tree’s
                   stability – a larger area is required to maintain a tree in viable health. It is only necessary to
                   calculate the SRZ when major encroachment into a TPZ is proposed.




22_11_21_TMP_Stockwell_Medihub                                                                         Page 20 of 22