Arborist Report inc VMP

Arborist Report
14 Serenity Close, Noosa Heads



The assessment included visual assessment of tree hazard and risk in accordance with the
International Society of Arboriculture’s (ISA) Tree Risk Assessment Manual (Dunster et al.
2013). Physical methods and/or exploratory techniques were not used in undertaking the
assessment. Arboricultural data recorded as part of the assessment included:

   ● Identification of risk targets,
   ● Tree dimensions,
   ● Site conditions,
   ● Overall condition and vigour,
   ● Canopy structure and form, disease and any other significant features,
   ● Trunk condition and form,
   ● Roots and root collar condition and form, and,
   ● Habitat features.

For each combination of tree hazard and risk target, risk categorisation was carried out in
accordance with the Tree Risk Assessment Manual (Dunster et al. 2013).

The TPZ and SRZ of the trees was calculated in accordance with Australian Standard AS
4970-2009 Protection of trees on development sites (Standards Australia 2009). The TPZ
is the principal means of protecting trees on development sites and is a combination of
the root area and crown area requiring protection (Standards Australia 2009).

Whilst it is possible to encroach into or make variations to the nominal TPZ for excavation,
fill or trenching, disturbances should generally be restricted to less than 10% of the TPZ
area (Standards Australia 2009). Such encroachments are considered minor. Where more
substantial encroachments are proposed or where proposed encroachment includes areas
within the SRZ, root investigations may be required (Standards Australia 2009). Where
encroachments are proposed, the area lost to encroachment should be offset with
additional area elsewhere contiguous with the TPZ. Assessment of the potential impacts
of encroachment could require an assessment of potential mitigating or site-specific
factors including inter alia (Standards Australia 2009):

   ● Physical location of roots,
   ● Tree species and tolerance to root disturbance,
   ● Age, size and vigor of tree,
   ● Lean and stability of tree,
   ● Soil characteristics,
   ● Drainage characteristics,
   ● The presence of existing or past structures or obstacles affecting root development,
      and,
   ● Building or infrastructure design methods (e.g. pier and beam, suspended slabs,
      cantilevered building sections, screw piles and tunnel-boring of pipes can be used to
      reduce the impacts of any encroachment).

‘Encroachment’ of a structure within the TPZ of greater than 10% is not equivalent to
‘impact’, particularly where site, tree or development characteristics are considered. For
example, a timber deck may result in major encroachment, however, is constructed using
methods which avoid disturbance of existing ground levels and structural roots (e.g. low-



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