© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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Tree Assessment
Site Address: Strathfield Square, Strathfield NSW Client: Strathfield Council Date: September 2016 Prepared by Ian Hills - Associate Diploma Horticulture. Cert III Arboriculture Diploma Arboriculture P: 0412 607 658 F: (02) 4393 6590 E: [email protected]
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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Table of contents
1.0 Summary ....................................................................................................................................... 3
Recommendations ............................................................................................................................... 3
2.0 Disclaimer ...................................................................................................................................... 4
3.0 Brief ............................................................................................................................................... 4
4.0 Method........................................................................................................................................... 4
4.1. Documents ............................................................................................................................... 4
5.0 Site Conditions ............................................................................................................................... 5
6.0 Tree Assessment ........................................................................................................................... 6
Tree Assessment (cont) ....................................................................................................................... 7
7.0 Tree Retention Value ..................................................................................................................... 8
8.0 Discussion ..................................................................................................................................... 9
9.0 Conclusions ................................................................................................................................. 12
10.0 Recommendations ..................................................................................................................... 12
11.0 Appendices ................................................................................................................................ 13
11.1. Safe Useful Life Expectancy Categories ............................................................................... 13
11.2 Tree Removal Concept Plan ................................................................................................. 14
11.3 Calculating Tree retention Value ........................................................................................... 15
11.4. References ........................................................................................................................... 15
11.5 Qualifications – Ian Hills ........................................................................................................ 15
Table of images
Figure 1 Subject site (source Google maps) ........................................................................................ 5 Figure 2 Trees 1 and 2 Eucalyptus microcorys .................................................................................. 10 Figure 3 Trees 3 and 4 Platanus x acerifolius .................................................................................... 10 Figure 4 Trees 5 and 6 Platanus x acerifolius appear in average condition ........................................ 11 Figure 5 Tree 19 Robinia pseudoacacia ‘Frisia’ ................................................................................. 11
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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1.0 Summary
Accurate Tree Assessment has been commissioned by Strathfield Council to provide an assessment of tree health and condition for twenty-two (22) trees growing in and around the Strathfield Square precinct. The site which is approximately 2860m² is completely paved to form roadways and areas of open-space and forms the hub of the Strathfield Town Centre; it is bounded by the Strathfield Railway Station to the North, Churchill Ave to the South, Strathfield Square to the East and The Boulevarde to the West.
Conclusions
The subject trees appear in various stages of decline associated with the lack of adequate root-zone volume which restricts water percolation and gaseous exchange leading to dieback of branches and poor form, and are not suited to retention. The increased maintenance requirement is not sustainable and places a burden on Council resources that could be more appropriately used elsewhere. The replacement of Tree 19 will require consultation with the Community to establish a fitting memorial to the lives lost in 1991. Redevelopment of the area should include the provision of replacement plantings of species better suited to the location, and must include adequate provision for the root-zone of those trees.
Recommendations
That the subject trees are removed and replaced in conjunction with the redevelopment of Strathfield Square by the Council. That the memorial Tree 19 Robinia pseudoacacia ‘Frisia’ is replaced in consultation with the community. That the replacement plantings are provided with adequate root-zone volume by using sub-surface planting chambers or gap-graded structural soils and permeable surface treatments.
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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2.0 Disclaimer
This report is to be read and considered in its entirety. The subject trees were inspected from the ground using Visual Tree Assessment methodology, no aerial investigations; underground or internal investigations were undertaken. It is the responsibility of the client to implement all recommendations contained in this report. The assessment is made having regard for the prevailing site conditions; and does not account for the effects that extreme weather events may have on trees. Photographs used in this report are originals taken at the time of inspection and are not altered in anyway. Information contained in this report reflects the condition of the trees at the time of the inspection. As trees are living organisms their condition will change over time, there is no guarantee that problems or deficiencies of the subject trees may not arise in the future. It must be accepted that living in close proximity to trees involves some level of risk. This report is for the use of the client Strathfield Council, to assist in determining tree management options in conjunction with the proposed re-development of the area; distribution to others is not permitted except with the express permission of the author, Ian Hills.
3.0 Brief
Accurate Tree Assessment has been commissioned by Strathfield Council to provide an assessment of tree health and condition for twenty-two (22) trees growing in and around the Strathfield Square precinct.
4.0 Method
An inspection of the subject trees was conducted from the ground on 21 September 2016. The assessment of the trees was made using a combination of both the relevant elements of Visual Tree Assessment (VTA) procedure (Matheny & Clark, 1994), (Mattheck & Breloer, 2004) with the aid of a Visual tree assessment form developed by International Society of Arborists in accordance with industry best practice. Tree height was determined using Silva Clinomaster™ clinometer. Tree canopy spread was determined using a 30 metre retractable tape. The DBH was determined using a Million™ 12 tree diameter tape. Sounding of the trunks was carried out using a Thor®710 soft faced hammer. The canopy structure was examined using binoculars from ground level. Trees were identified and each tree allocated a reference number which has been marked on the Tree Removal Concept Plan. 4.1. Documents
Leon Limberiou, Council’s Tree Management Officer has provided a copy of the Tree Removal Concept Plan prepared by Strathfield Council dated 16 September 2016, which has been used as a reference to this report. (Appendix 11.2)
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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5.0 Site Conditions
The site which is approximately 2860m² is completely paved to form roadways and areas of open-space and forms the hub of the Strathfield Town Centre; it is bounded by the Strathfield Railway Station to the North, Churchill Ave to the South, Strathfield Square to the East and The Boulevarde to the West. The subject trees provide shade and some relief from the hard landscaping that dominates the precinct which is frequented by commuters and patrons of the many restaurants and cafes which contribute to the areas high occupation rate. Soil type has not been investigated but it is likely to be highly disturbed due to the re-profiling required when constructing the various roadways and paved areas. The site is protected from strong winds by surrounding structures and the grouping of the subject trees.
Figure 1 Subject site (source Google maps)
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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6.0 Tree Assessment
No. Common Name Species DBH (mm)
TPZ (M)
Height X Spread
Condition ULE Comments
1 Tallow-wood Eucalyptus microcorys 400 4.8 6 6 F 4A Topped and lopped apical meristem removed, torsional split in East side of trunk, 100% TPZ paved
2 Tallow-wood Eucalyptus microcorys 480 5.76 8 10 F 4A Topped and lopped apical meristem removed, torsional split South side of trunk
3 London Plane Tree Platanus × acerifolia 380 4.56 8 8 F 4A Topped, severe dieback of apical meristem, co-dominant from 1.6 metres
4 London Plane Tree Platanus × acerifolia 380 4.56 8 8 G 4A Structrally sound, epicormic growth noted, 100%TPZ paved
5 London Plane Tree Platanus × acerifolia 320 3.84 8 8 G 4A Structrally sound, epicormic growth noted, 100%TPZ paved
6 London Plane Tree Platanus × acerifolia 370 4.44 8 7 F 4A Major asymmetry with excessive end-weight to the South.
7 London Plane Tree Platanus × acerifolia 250 3.0 6 5 G 4A Semi-mature tree, epicormic growth noted
8 London Plane Tree Platanus × acerifolia 410 4.92 8 5 G 4A Excessive branch end-weight North, epicormic growth noted
9 London Plane Tree Platanus × acerifolia 380 4.56 12 8 G 4A Generally symmetrical, crown raised
10 London Plane Tree Platanus × acerifolia 360 4.32 12 8 G 4A Generally symmetrical, multiple attachments at 3 metres, epicormic growth noted
11 London Plane Tree Platanus × acerifolia 340 4.08 12 6 P 4A Excessive branch dieback and epicormic growth, crown raised.
12 London Plane Tree Platanus × acerifolia 350 4.2 12 6 P 4A Excessive branch dieback and epicormic growth, crown raised.
13 London Plane Tree Platanus × acerifolia 370 4.44 12 8 P 4A Excessive branch dieback, epicormic growth, lopped removing apical meristem
14 London Plane Tree Platanus × acerifolia 360 4.32 12 8 F 4A Leans South over cafe, excessive branch dieback and epicormic growth
15 Tallow-wood Eucalyptus microcorys 420 5.04 12 8 F 4A Leans North-west over road, excessive dieback and epicormic growth, pavement damaged, co-dominant from 6 metres
16 Tallow-wood Eucalyptus microcorys 280 3.36 12 5 F 4A Included bark in union of co-dominant trunks from 7 metres
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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Tree Assessment (cont)
DBH – Trunk diameter at 1.4 metres TPZ = Tree Protection Zone (calculated in accordance with AS4970) Vigour - P = Poor, F = Fair, Av = Average, G =Good ULE = Useful Life Expectancy (Barrel, J -1993-95) Age class – J = Juvenile, SM =Semi-mature M = Mature, OM= Over mature
No. Common Name Species DBH (mm)
TPZ (M)
Height X Spread
Condition ULE Comments
17 Tallow-wood Eucalyptus microcorys 570 6.84 12 8 P 4A Asymmetrical form with excessive branch end-weight South over roadway, severe branch dieback, severe pavement damage
18 Tallow-wood Eucalyptus microcorys 540 6.48 12 8 F 4A Excessive branch dieback and epicormic growth, girdling roots and pavement damage, excessive branch end-weight over building
19 Golden Locust Robinia pseudoacacia
‘Frisia’ 125 2.0 4 5 P 1C
Commemorative tree, severe asymmetry leaning to the South, evidence of White Rot fungus at base of trunk, sun-scald on exposed section of trunk
20 Tallow-wood Eucalyptus microcorys 360 4.32 8 8 P 4A Topped apical meristem removed, poor form
21 Tallow-wood Eucalyptus microcorys 240 2.88 5 6 P 4A Topped apical meristem removed, poor form
22 Tallow-wood Eucalyptus microcorys 550 6.6 8 8 P 4A Topped apical meristem removed, poor form, girdling roots, torsional wound South-east side of trunk.
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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7.0 Tree Retention Value
Vigour – based on production of new growth and wound occlusion Av = Average, P = Poor, F = Fair. Condition – based on structural faults or diseases, or provides comparison to an archetypal example of the species. Suitability - High = adequate space to accommodate future growth and growing conditions suited to the species, Medium = inadequate space and good growing conditions, Low = inadequate space and poor growing conditions. Retention Value – combines Landscape significance and sustainability to rank the trees value (Refer Appendix 11.3).
No. Species Sustainability Landscape
Significance Rating
Retention Value Health and Vigour Condition Suitability
1 Eucalyptus microcorys Average Fair Low <5 years 4 Very low
2 Eucalyptus microcorys Average Fair Low <5 years 4 Very low
3 Platanus × acerifolia Poor Fair Low <5 years 5 Very low
4 Platanus × acerifolia Average Good Low <5 years 4 Very low
5 Platanus × acerifolia Average Good Low <5 years 4 Very low
6 Platanus × acerifolia Average Fair Low <5 years 5 Very low
7 Platanus × acerifolia Average Good Low <5 years 4 Very low
8 Platanus × acerifolia Average Good Low <5 years 4 Very low
9 Platanus × acerifolia Average Good Low <5 years 4 Very low
10 Platanus × acerifolia Average Good Low <5 years 5 Very low
11 Platanus × acerifolia Average Poor Low <5 years 5 Very low
12 Platanus × acerifolia Average Poor Low <5 years 5 Very low
13 Platanus × acerifolia Average Poor Low <5 years 5 Very low
14 Platanus × acerifolia Average Fair Low <5 years 4 Very low
15 Eucalyptus microcorys Average Fair Low <5 years 4 Very low
16 Eucalyptus microcorys Average Fair Low <5 years 4 Very low
17 Eucalyptus microcorys Average Poor Low <5 years 5 Very low
18 Eucalyptus microcorys Average Fair Low <5 years 4 Very low
19 Robinia pseudoacacia
‘Frisia’ Average Poor Low <5 years 5 Very low
20 Eucalyptus microcorys Poor Poor Low <5 years 5 Very low
21 Eucalyptus microcorys Poor Poor Low <5 years 5 Very low
22 Eucalyptus microcorys Poor Poor Low <5 years 5 Very low
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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8.0 Discussion The subject species Eucalyptus microcorys and Platanus x acerifolia both have the potential to become large trees with canopy height excess of 30 metres and correspondingly broad spread; both species are a common feature of streetscapes throughout Australia. In this instance the trees are struggling to reach half their potential size and present excessive dieback of branches and epicormic growth indicative of trees experiencing severe stress. The trees’ location within the pavement of the Strathfield Square and the lack of permeable surface treatment reduces the ability of water to percolate into the root-zone as well as limiting gaseous exchange between the soil and the atmosphere and is the likely cause of the decline in the trees condition. It is also apparent that trenching for various services transects the root-zones of a number of the trees and is likely to have severed numerous roots which has caused some trees to decline further than others. The decline of the trees has led to an increased requirement for maintenance pruning recently, while this has resolved the immediate issue of falling deadwood continued pruning operations are a burden on Council resources and are not sustainable in the long term, notwithstanding the fact that the trees are becoming misshapen. Tree 19 Robinia pseudoacacia ’Frisia’ was planted as a memorial to those who lost their lives in the ‘Strathfield Massacre’ of 1991 and as such its management will require special consideration. The tree has become poorly formed due to a lack of support during the formative growth period and now leans excessively over the pedestrian footpath. Unfortunately the habit of the tree will not be improved by remedial pruning and its removal and replacement is the preferred management option; this will need to be carried out in a sensitive manner in consultation with the Strathfield community. Due to their declining condition and generally being unsuitable to the growing conditions in the Strathfield Square the subject trees should not be considered as a constraint on the redevelopment of the area that is proposed by Council. During the redevelopment it is imperative that new plantings are provided with adequate root zone volume so that the errors made with the current planting are not repeated. This may involve the use of sub-surface planting chambers or the use of gap graded structural soils to ensure sufficient root zone volume is available to new plantings. The benefits of providing adequate root-zone volumes are reduced maintenance cost of trees and paved surfaces, which will be protected against root damage. The selection of species will also play a large part in a successful redevelopment of the area preference should be given to those species that have fibrous or generally non- destructive root systems, such as Palms or Proteaceae family; species to be avoided might include (but are not limited to) Ficus, Triadica and Eucalyptus.
Example of tree planting chamber using structural soil and support structure.
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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Figure 2 Trees 1 and 2 Eucalyptus microcorys
Figure 3 Trees 3 and 4 Platanus x acerifolius
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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Figure 4 Trees 5 and 6 Platanus x acerifolius appear in average condition
Figure 5 Tree 19 Robinia pseudoacacia ‘Frisia’
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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9.0 Conclusions
The subject trees appear in various stages of decline associated with the lack of adequate root-zone volume which restricts water percolation and gaseous exchange leading to dieback of branches and poor form, and are not suited to retention. The increased maintenance requirement is not sustainable and places a burden on Council resources that could be more appropriately used elsewhere. The replacement of Tree 19 will require consultation with the Community to establish a fitting memorial to the lives lost in 1991. Redevelopment of the area should include the provision of replacement plantings of species better suited to the location, and must include adequate provision for the root-zone of those trees.
10.0 Recommendations
That the subject trees are removed and replaced in conjunction with the redevelopment of Strathfield Square by the Council. That the memorial Tree 19 Robinia pseudoacacia ‘Frisia’ is replaced in consultation with the community. That the replacement plantings are provided with adequate root-zone volume by using sub-surface planting chambers or gap-graded structural soils and permeable surface treatments.
Ian Hills - Consulting Arborist
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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11.0 Appendices
11.1. Safe Useful Life Expectancy Categories
1: Long SULE: Trees that appeared to be retainable at the time of assessment for more than 40 years with an acceptable level of risk. (a) Structurally sound trees located in positions that can accommodate future growth. (b) Trees that could be made suitable for retention in the long term by remedial tree care. (c) Trees of special significance for historical, commemorative or rarity reasons that would warrant extraordinary efforts to secure their long term retention. 2: Medium SULE: Trees that appeared to be retainable at the time of assessment for 15–40 years with an acceptable level of risk. (a) Trees that may only live between 15 and 40 more years. (b) Trees that could live for more than 40 years but may be removed for safety or nuisance reasons. (c) Trees that could live for more than 40 years but may be removed to prevent interference with more suitable individuals or to provide space for new planting. (d) Trees that could be made suitable for retention in the medium term by remedial tree care. 3: Short SULE: Trees that appeared to be retainable at the time of assessment for 5–15 years with an acceptable level of risk. (a) Trees that may only live between 5 and 15 more years. (b) Trees that could live for more than 15 years but may be removed for safety or nuisance reasons. (c) Trees that could live for more than 15 years but may be removed to prevent interference with more suitable individuals or to provide space for new planting. (d) Trees that require substantial remedial tree care and are only suitable for retention in the short term. 4: Remove: Trees that should be removed within the next 5 years. (a) Dead, dying, suppressed or declining trees because of disease or inhospitable conditions. (b) Dangerous trees because of instability or recent loss of adjacent trees. (c) Dangerous trees because of structural defects including cavities, decay, included bark, wounds or poor form. (d) Damaged trees that are clearly not safe to retain. (e) Trees that could live for more than 5 years but may be removed to prevent interference with more suitable individuals or to provide space for new planting. (f) Trees that are damaging or may cause damage to existing structures within 5 years. (g) Trees that will become dangerous after removal of other trees for the reasons given in (a)to(f) (h) Trees in categories (a) to (g) that have a high wildlife habitat value and, with appropriate treatment, could be retained subject to regular review. 5: Small, young or regularly pruned: Trees that can be reliably moved or replaced. (a) Small trees less than 5m in height. (b) Young trees less than 15 years old but over 5m in height. (c) Formal hedges and trees intended for regular pruning to artificially control growth.
© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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11.2 Tree Removal Concept Plan
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© Copyright Accurate Tree Assessment Ian Hills – Arborist ph: 0412 607 658 Project: Strathfield Square, Strathfield NSW September 2016
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11.3 Calculating Tree retention Value
(Source NUFTM) Modified by A Morton from Couston and Howden (2001) Tree retention values table Footprint Green Pty Ltd Australia)
11.4. References
Clark R.J & Matheny N (1998) Trees & Development – A technical guide to Preservation of trees during land development: International Society of Arboriculture Mattheck C., Breloer, (1999) The Body Language of Trees – a handbook for failure analysis 5th ed., London: The Stationery Office, U.K Barrell, J. (1993-95) ‘Pre-planning Tree Surveys Safe Useful Life Expectancy (SULE) is the Natural Progression’ Arboricultural Journal Vol. 17, PP 33 - 46, Academic Publishers, Great Britain. Standards Australia. 2007 ‘Australian Standard 4373-2007 ‘Pruning of Amenity Trees’, Standards Australia GPO Box 476 Sydney NSW 2001, Australia. Standards Australia. 2009 ‘Australian Standard 4970-2009 Protection of Trees on Development Sites’ Standards Australia GPO Box 476 Sydney NSW 2001, Australia. Newcastle City Council (2013), Newcastle Urban Forest, Technical Manual Newcastle City Council PO Box 489,Newcastle NSW 2300 Google Maps 2016 [online] Available at: http://maps.google.com.au/maps [accessed 21 September 2016]
11.5 Qualifications – Ian Hills
Associate Diploma Horticulture - Ryde TAFE 1984 AQF3 Horticulture (Arboriculture) - Ourimbah TAFE 1998 AQF5 Diploma Horticultu re (Arboriculture) - Kurri Kurri TAFE 2009 (Dux) Cert No. 5934155
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