Attachment 008
TREE REPORT
Client: City of Vincent
Contact: Kim Godfrey – Horticultural Officer
Site: 125 Richmond St, Leederville, WA
Prepared by: Jonathan Epps IACA
p - (08) 9314 5102
m - 040 222 1517
e - [email protected]
MEMBER OF
13 December 2014
Attachment 008
INTRODUCTION
Kim Godfrey requested Jonathan Epps to carry out a tree inspection
on a mature tree (subject tree) in the front garden of 125 Richmond
Street, Leederville. It is proposed by the developers to demolish the
present building and erect a new structure. The City’s planning
department is keen to incorporate the subject tree in the new
development and arboricultural guidelines are required on which
measures are necessary to protect the tree during the development,
including any remedial works. Mr Godfrey requires information on
the subject tree’s health and structural status. Also the calculated
distance required from the tree stem in order that the development
does not cause damage and/or health issues that may arise at a
later date.
TREE INSPECTION
The tree survey/inspection took place on Friday 12 December 2014.
The tree inspection took place from ground level. The weather was
warm, sunny and clear - air temperature was around 22o C.
SUBJECT TREES
The subject tree is a mature WA Flooded Gum – Eucalyptus rudis –
see image below
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INSPECTION DETAILS
The subject tree stands in the front garden of 125 Richmond Street,
Leederville 500mm on the north side of the public footpath adjacent
to the street.
The garden itself appears to be un-reticulated and contains other
mature specimens. These include an unremarkable, poorly
maintained Liquidambar and a Redcap/Illyarrie Gum with a typical
asymmetrical form.
The subject tree has a codominant stem around 2.5m agl. It has a
history of pollarding which has occurred at two points, 4m and 5m
respectively agl – see image below left
There is a history of power line clearance on the street (north) side
– see image above right
Active termites are present on the lower stem underneath loose
outer bark – see image below left. Blastomania (stem galls) in the
form of large irregular woody growths are present on the lower
stem. These are caused by the proliferation of adventitious buds on
the stem. The lower stem appears to remain sound.
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Final cut wounds are present on the stem and at old pollard
terminals. These have occluded well and no cavities were seen. The
foliage is of good colour, size and density although Sugar Lerp was
noted on some of the leaves on the lower branches.
All pollard points appear to be sound, no incidence of included bark
seen.
DISCUSSION
The subject tree appears to be a former bush specimen. Such trees
typically grew near natural water features such as lakes and rivers.
The subject tree may have grown near a now-extinct lake.
Termites in urban trees are often a cause of general concern to the
public. Many of our mature urban trees are bushland remnants and
have active termites. Trees can exist for many years with such
organisms and remain sound. The use of ultra sound (Picus) may
give a more detailed examination. The tomograph (picture) will
show any decay present but what it won’t show is the type of decay
and possibly how severe it is. A Resistograph measurement may
give a more accurate local reading. It is advised that within five
years the subject tree may require a Resitograph reading.
Sugar Lerps are a common urban pest and do not normally cause
debilitating and long term health issues.
The subject tree was probably pollarded many years ago because of
its proximity to the overhead power lines. Pollading was a common
management option forty years ago. The re-grown pollards on the
subject tree only appear to be around fifteen to twenty years old.
Although there appear to be no cavities at the pollard points the
developer may consider re-pollarding before development begins as
this will help with construction access. In any case it is
recommended that the branches in the low crown on the east
(Oxford St) and west side be removed, again to allow easier site
access.
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TREE PROTECTION ON DEVELOPMENT SITES
The results of damage to trees intentional or otherwise may not be
seen for months or possibly years until after the event has
occurred. Unintentional root severance and/or root/soil compaction
may not result in tree decline until many years after the event. It is
then practically impossible to appoint claims of damage or loss to
the original parties concerned. It is therefore important that the
controlling authorities not only offer protection guidelines but
appoint a person or authority that polices the guidelines during and
after the proposed construction/development activity. A Project
Arborist is usually appointed to manage tree protection on
development sites – see AS 4970 – 2009 see page 6 1.4.4 – Project
Arborist.
In 2009 a new Australian Standard was released to give advice to
those professionals concerned with retaining mature trees on
development sites. This document is AS 4970 – 2009 Protection of
Trees on Development Sites. These guidelines inform the reader on
distances required for creating a TPZ – Tree Protection Zone - that
protects both the tree crown and root area. These distances are
usually out beyond the drip line (edge of canopy) of the tree. In
more practical circumstances where the proposed development
encroaches into the TPZ a second more critical measurement is
calculated. This is called the SRZ – Structural Root Zone. This is the
minimum calculated distance that may intrude the TPZ ON ONE
SIDE ONLY without compromising the structural integrity of the
affected tree(s). This SRZ distance usually is at a distance from the
main stem where the main lateral roots begin their ‘zone of rapid
taper’, ie the point on the main lateral roots where the diameter
diminishes rapidly. – see ‘Dictionary for Managing Trees in Urban
Environments’ – Draper & Richards 2009 pp 178.
It is the SRZ measurement that was used in this project to
determine the distance of the proposed development from ONE
SIDE OF THE SUBJECT TREE ONLY.
CALCULATION OF SRZ
SRZ radius = (D x 50)0.42 x 0.64, where D = trunk diameter, in m,
measured above the root buttress, (from page 12 AS 4970).
Therefore:
Subject tree, where D (average) = 1.65m, (1.65 x 50)0.42 x 0.64
= 6.38 x 0.64
SRZ = 4.08m
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METHODOLOGY - SIMS© - The subject tree was inspected from
ground level.
Root plate heave and/or disturbance
Exposed roots – lowering of soil level/grade – trip hazard
Infill at base of stems – raised soil levels – collar rot
Girdling roots – roots encircling the stem may cause ‘ring barking’ –
bark necrosis
Basal cavities – hollows, fungal brackets/fruiting bodies
Crown galls
Termite activity
Climbing plants
Proximity of underground/overground services
Proximity of aboveground structures, eg houses, retaining walls, etc
Bark tears, lesions, splits and cracks
Oedema – and other unnatural swollen & cracked areas in bark
tissue
Physical abnormalities, eg lightning strikes, bridge grafts, etc
Unnatural change in bark colour, texture and form
Compression folds in bark
Decay pockets in stem
Excessive gum, sap, kino exudation and/or weeping
Borer, cossid moth and other insect activity
Included bark at major stem and branch unions
Evidence of tree surgery and infrastructure, eg cabling, Cobra/Yale
Bracing, signs and other abiotic tree attachments
Branch attachments
Evidence of topping, lopping and/or pollarding history
Flush cuts – removal of branch collar
Branch sockets – areas where branches have been torn out and
away from union
Branches of uneven taper
Crossing, broken and hung-up branches – branch stubs
Die-back symptoms – stag heading and reduction in foliage density
Major dead wood – over 10mm in diameter
Minor dead wood – under 10mm in diameter
Mycoplasma attack
Foliage – change in lamina colour, size, shape and thickness
variation
Epicormic growth
Growth habit of tree – leaning, crooked or asymmetrical growth
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RECOMMENDATIONS
The structural roots must be protected by the erection of a fence at
least 4m from the stem on all sides.
On no account must the following occur beneath the drip line of the
subject tree during the development process:
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Storage of materials
Mixing of materials – cement, chemicals surfactants etc
Parking of plant, machinery, vehicles, trailers etc
Erection of temporary structures
Any in-ground or other intrusions such as trenching
Damage to the tree in any form eg sign erection/cable
attachment
Placement of fill/soil and/or grade changes
Any other activities or otherwise that may affect the structure
and health of the subject tree.
Pruning recommendations prior to development process:
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Consider re-pollarding the tree
OR/ - remove low branches on east (Oxford St), west and
north (Richmond St) side.
Other Treatments

Control termites using BIFENTHRIN as a soil drench/barrier
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CONCLUSION
Thought must be given not only to retaining the subject tree as
good as the intensions are but also serious thought must be given
as to how the tree is retained. What will its new immediate
environment be like?
Ideally the subject tree would benefit from some form of root
protection by retaining or creating a ‘natural’ area beneath the
canopy zone. This can be a simple native garden with local
maintenance free ground cover or shrubs. Certainly it is hoped that
the subject tree is associated with some form of surrounding
vegetation and not left in isolation like a pimple on a pumpkin.
Remnant bush trees deserve better.
The SRZ guidelines above are guides only – common sense must
prevail. Obviously roots extend out beyond drip lines and great care
must be taken in these areas during the construction process.
DISCLAIMER STATEMENT
Jonathan Epps is an independent arboricultural consultant. He is professionally qualified and a
founding member of the Institute of Australian Consulting Arboriculturists. Tree examinations, for
various outcomes, including structural defects and health analysis are a large part of his practice.
General advice is given for all urban trees. These examinations (Visual Tree Assessments - VTA) are
carried out from ground level. Great care is undertaken during tree examinations but it is impossible
to detect every condition which could possibly lead to be structural failure of a tree. Trees may fail for
an unspecified reason that is not fully understood by the profession. The problem(s) may be
underground or hidden inside the tree. For this reason, VTA’s are not guaranteed under all
circumstances or for a specified period of time. In addition, recommended treatment cannot be
guaranteed including those treatments carried out which are not recommended by Mr Epps.
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