19_01_16_AIA_Alba_25 Kauri St_V1 · MCU18/0165

                                                                                                           Consult Arborist

A PPENDIX 1 - D EFINITION OF T ERMS
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:       The 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, a reduced crown size and annual increment growth, extensive hollowing,
                    crown collapse, low vigour, advance 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 deadwood 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. The 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:
 DBH:               Diameter at Breast Height - The approximate diameter of the trunk is measured visually in millimetres at a
                    height of 1.4m.
 TPZ:               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 and
                    crown area requiring protection. This area should 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 is calculated for each tree by multiplying its trunk diameter at 1.4m above ground by
                    12, e.g. 300mm [email protected] x 12 = 3.6m Tree Protection Zone (TPZ)
                    A TPZ should not be less than 2m or greater than 15m (unless crown protection is required).
 SRZ:               Structural Root Zone (SRZ), as specified in AS 4970-2009 Protection of trees on development sites, is 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.
                    The SRZ for trees with a trunk diameter less than 150mm will be 1.5m.
 Tree Retention Value:
 This retention value comes from the Institute of Australian Consulting Arborists (IACA), 2010, IACA Significance of a Tree,
 Assessment Rating System (STARS), Institute of Australian Consulting Arboriculturists, Australia, www.iaca.org.au -
 http://www.iaca.org.au/home/index.php/publications/71-stars
 The process uses the Retention Value – Priority Matrix by assessing the Tree Significance Assessment Criteria and crossing
 it with the Estimated Life Expectancy to determine the following ratings:
 High:              Priority for Retention
                    These trees are considered important for retention and should be retained and protected. Design
                    modification or relocation of building/s should be considered to accommodate the setbacks as prescribed by
                    the Australian Standard AS4970 Protection of trees on development sites. Tree sensitive construction
                    measures must be implemented e.g. pier and beam etc. if works are to proceed within the Tree Protection
                    Zone.
 Medium:            Consider for Retention
                    These trees may be retained and protected. These are considered less critical; however, their retention
                    should remain a priority with removal considered only if adversely affecting the proposed building/works and
                    all other alternatives have been considered and exhausted.
 Low:               Consider for Removal
                    These trees are not considered important for retention, nor require special works or design modification to
                    be implemented for their retention.
 Remove:            Priority for Removal
                    These trees are considered hazardous, or in irreversible decline, or weeds and should be removed
                    irrespective of development.




19_01_16_AIA_Alba_25 Kauri St_V1                                                                                     Page 18 of 19