Tree Report ATS311-001GeoStAmd€¦ · Arborman Tree Solutions Pty Ltd – Professionals in Arboriculture Phone: (08) 8240 5555 23 Aberdeen Street ATS3611-001GeoStAmd – 27 May 2016

Tree Report ATS311-001GeoStAmd

Tree Report for Greg Molfetas

Re: 1 George Street, Parkside (formerly Caramar Clinic 179 Greenhill Road)

Report commissioned by: Greg Molfetas

Report compiled by: Arborman Tree Solutions Pty Ltd Daniel Tuckwell – Consulting Arboriculturist

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Arborman Tree Solutions Pty Ltd – Professionals in Arboriculture Phone: (08) 8240 5555

23 Aberdeen Street ATS3611-001GeoStAmd – 27 May 2016 Fax: (08) 8240 4525

Port Adelaide SA 5015 Email: [email protected]

Table of Contents Brief .......................................................................................................................................................................... 3

Supplied Information ........................................................................................................................................................ 3

Executive Summary ......................................................................................................................................................... 3

Assessment ............................................................................................................................................................. 4

Observations .................................................................................................................................................................... 4

Development Plan Principles of Development Control – Tree 1 ................................................................................... 6

Development Plan Objectives and Principles of Development Control – Trees A and B ............................................ 9

Discussion / Conclusion ......................................................................................................................................... 10

Recommendations ................................................................................................................................................. 11

Glossary ................................................................................................................................................................. 13

References............................................................................................................................................................. 14

Appendix A – Tree Location .................................................................................................................................. 15

Appendix B – Tree Protection Zones ..................................................................................................................... 16

Appendix C – Preliminary Design Response, November 2015 – Tree 1 .............................................................. 17

Appendix D – SK-04-10015 Basement Floor Plan, SK-05-10015 Ground Level Floor Plan, 23 May 2016 ......... 17

Appendix E – Paving Construction within a TPZ ................................................................................................... 19

Appendix F - AS4970-2009 Schedule of Compliance checks ............................................................................... 21




Brief

I was asked to carry out an inspection, from ground level, of the Phytolacca dioica (Ombu) and a Corymbia citriodora (Lemon Scented Gum) located at 1 George Street, Parkside formerly ‘Caramar Clinic’ 179 Greenhill Road and two Ulmus x hybrida (Dutch Elm) within the verge of Greenhill Road to provide information in relation to the following points: - Assess the general condition and structure of the subject trees. Assess the trees against the current provisions of the Development Act 1993 relating to

Regulated and Significant Trees. Identify and define the appropriate Tree Protection Zone and Structural Root Zone for the

trees. Determine the extent and long-term effect of possible damage to the subject trees associated

with the adjacent development and supporting infrastructure. Recommend appropriate action for both the immediate and ongoing management of the

trees. This may include crown and root zone treatments and management principles. Provide any additional relevant information as appropriate. Supplied Information:

SK-04-10015 Basement Floor Plan, 23 May 2016

SK-05-10015 Ground Level Floor Plan, , 23 May 2016

Preliminary Design Response for Pre-lodgement Meeting – JPE Design Studio 20th November 2015

Executive Summary:

This report ATS3611-001GeoStAmd replaces ATS3402-001GeoSt issued on the 27 January 2016 and considers the minor alterations to the plans as they were proposed at that time. This assessment continues to support the proposed development, despite a Tree Protection Zone (TPZ) encroachment that is recognised as ‘major’ under Australian Standard AS4970–2009 Protection of trees on development sites. This is due to 3.3.4 (g) of the standard being considered and protection measures that have been recommended to minimise/manage potential tree-damaging activity.




Assessment

Observations

Tree 1 - Phytolacca dioica (Ombu)

Assessment Date: 20 January 2016 Height: 14 metres Spread: 17 metres Age: Mature Useful Life Expectancy: > 10 years Health: Good Structure: Good Circumference: > 3.00 metres Legislative Control Status: Significant – and Listed within City of Unley development plan TPZ: SRZ: 15.00 metres 5.43 metres Retention Rating: High: Good tree worthy of retention with no significant faults or health concerns. The tree is located within the southeastern quadrant of the subject land adjacent to the eastern

boundary. The tree is marked Tree 1 on the attached plan. (See Appendix A) The form consists of eight stems from a high buttress supporting an array of lateral branching

that is complex and intertwining. The overall crown shape is a broad dome. The root zone includes the cleared subject land as well as limited open soils and a pathway at

grade beyond the eastern boundary. From approximately 1.50 metres east of that boundary a below ground level carparking area has been established for some years. No obvious disturbance has occurred to this area in recent times other than the clearance of pre-existing structures and surfaces within the subject land. (See Image 1.)




Health is good as indicated by the good foliage density and good foliage colour that is normal with no pest or disease identified within the crown.

Structure is good as indicated by the good root buttressing that leads into good stem and

branch taper and unions that are sound. The structure is typical for the species other than a disproportionate crown size with respect to the diameter of the stems at breast height (DBH). However, there is a lack of failure history and good options for future management.

19th November 2014 28th January 2015

27th December 2015

Image 1.




Development Plan Principles of Development Control – Tree 1

The subject tree attains a “Significant” trunk circumference measurement and is therefore required to be assessed to determine if it achieves any of the Principles of Development Control listed within the City of Unley Development Plan as follows:-

a) The tree makes an important contribution to the character or amenity of the local area; the tree is large, healthy and notable from surrounding vantage points.

b) The species is not indigenous to the local area. c) The subject tree does not represent important habitat for indigenous fauna; as an introduced

native that does not display suitable nesting hollows this tree has limited habitat value. d) The subject tree is not linked to a wildlife corridor or remnant area of native vegetation; the

original vegetation in this area was cleared during the areas development. e) The subject tree is not important to the maintenance of biodiversity in the local environment;

as a non-native (exotic) this tree has limited biodiversity value. f) The tree forms a notable visual element to the landscape of the local area; the tree is

considered to be an eminent feature of the local landscape and is listed as a Significant Tree within the City of Unley development plan.

In the case of tree-damaging activity, the following points are also considered:-

A Significant Tree should not be removed or damaged other than where it can be demonstrated that one or more of the Principles of Development Control listed within the City of Unley Development Plan apply. These Principles of Development Control are discussed as follows:

a) The work is not required for the removal of deadwood or treatment of disease, however it is in the general interests of tree health.

b) The work is not required due to an unacceptable risk to public and private safety; the tree does

not represent an unacceptable risk. c) The tree is not within a Bushfire Prone Area. d) The tree is not causing or threatening to cause substantial damage to a substantial building or

structure of value. e) The aesthetic appearance and structural integrity of the subject tree will be maintained both

during and post the development process. The development does involve groundwork activities such as excavation, filling and sealing of surrounding surfaces. However, the works are to occur within an area of the root zone that was previously sealed until late 2014, early 2015. Management options are available to protect the root system of the Significant Tree and therefore no adverse affect to the aesthetic appearance, health and integrity is expected. The land division and development will not result in a substantial tree-damaging activity occurring to a Significant Tree.




Tree 2 - Corymbia citriodora (Lemon Scented Gum)

Assessment Date: 20 January 2016 Height: 16 metres Spread: 18 metres Age: Mature Useful Life Expectancy: < 5 years Health: Good Structure: Fair-Poor Circumference: 2.37 metres Legislative Control Status: Not Regulated Retention Rating: Low: Damage or structural defects that have minimal remedial management options which limit the

ULE. The tree is located within the northwestern quadrant of the subject land adjacent to the western

boundary. The tree is marked Tree 2 on the attached plan. (See Appendix A) The form consists of a single stem and an array of lateral branches that create a sprawling

and open crown shape that is moderately biased to the east. The root zone includes the foot path and roadway of George Street to the west as well as

limited open soils, the former dwelling and an in ground swimming pool (within ten metres) within the subject land. No recent disturbance to the area was noted during assessment.

Health is good with good foliage density and colour that is normal with no pest or disease

identified within the crown. Structure is fair to poor with moderate to low branch taper and terminal foliation throughout the

form that is typical for the species. The failure history is of medium diameters from between 0.50 and one metre from attachment.




Trees A and B – Ulmus x hybrida ‘hollandica’ (Dutch Elm) Assessment Date: 20 January 2016 Average Height: 12 metres Average Spread: 7 - 8 metres Average Age: Mature Average Useful Life Expectancy: > 10 years Average Health: Average Structure: Good Good Average Circumference: Average TPZ: Average SRZ: 2.63 metres 9.72 metres 3.10 metres Legislative Control Status: Regulated Retention Rating: High: Good trees worthy of retention with no significant faults or health concerns. The trees are located within the council verge to the north of the subject land. The trees are

marked Trees A and B on the attached plan. (See Appendix A) The forms consist of a single stem and an array of lateral branches that create a domed crown

shape. The root zones include the foot path and roadway of Greenhill Road to the north as well as

open soils within the subject land. No recent disturbance to the area was noted during assessment.

Health is good with good foliage density and colour that is normal with no pest or disease

identified within the crown. Structure is good as indicated by the good root buttressing that leads into good stem and

branch taper and unions that are sound. A failure history is is not evident.

Tree A Tree B




Development Plan Objectives and Principles of Development Control – Trees A and B

The subject trees attain a “Regulated” trunk circumference measurement and are therefore required to be assessed to determine if they achieve any of the Development Plan Objectives and Principles of Development Control listed within the City of Unley Development Plan as follows:- a) The trees significantly contribute to the character or visual amenity of the local area. b) The species is not indigenous to the local area. c) The species is not rare or endangered. d) The trees do not represent important habitat for indigenous fauna; as introduced exotics that

do not display suitable nesting hollows these trees have limited habitat value. In the case of tree-damaging activity, the following points are also considered:-

A Regulated Tree should not be removed or damaged other than where it can be demonstrated that one or more of the Development Plan Objectives and Principles of Development Control listed within the City of Unley Development Plan apply. These are discussed as follows:

a) The trees are not diseased and their Useful Life Expectancy is extended. b) The trees do not represent a material risk to public or private safety. c) The trees are not causing damage to a building. d) Development that is reasonable and expected and is not impeded by the retention of these

trees. e) Work is not required for the removal of dead wood or the treatment of disease, however some

measures are recommended in the general interests of the health of the trees. Tree damaging activity other than removal is to maintain the aesthetic appearance and structural integrity of the trees. The recommended protection measures are designed to achieve these goals.




Discussion / Conclusion

A proposal to develop within the Tree Protection Zone (TPZ) of controlled trees that includes surfaces and excavations is considered below (See Appendix C). Please note that whilst Trees A and B are not within the subject land, they are potentially impacted by these activities. The subject trees are identified as Significant (Tree 1), Exempt due to the proximity of an in-ground swimming pool (Tree 2) and Regulated (Trees A and B). Trees 1, A and B are therefore controlled under the Development Act 1993, whilst the management of Tree 2 is at the discretion of the tree owner/manager. All of the controlled trees are noted to be in good overall health and structure, however despite the good health of Tree 2, it has a fair to poor structure. All other trees on site are Unregulated. To be discussed here are measures to preserve the good overall health and structure of the controlled trees, whilst the good health of Tree 2 is irrelevant due to its structural condition, which suggests it should be removed. The TPZ encroachment for Tree 1 is recognised as a ‘major’ encroachment within Australian Standard AS4970–2009 Protection of trees on development sites. Within AS4970–2009 3.3.4 (g), the presence of existing or past structures or obstacles affecting root growth should be considered. Root growth will be minimal within the encroachment area and supplemental root growth will exist to the south of the tree. Additionally, there is less development than previously existed proposed to the west of the tree. Therefore a potential exists for the growing area to be enhanced. Altered plans for the Basement and Ground Floor Levels of the development are supplied for this report and shown in Appendix D. The impact of encroachment within the calculated TPZ created by the proposed basement, is not necessarily increased with the completion of the ground level works. Points 9 and 10 within the Recommendations are able to minimise the impacts of those works. The note following Point 5 is also relevant, as root activity is not expected to be critical within the encroachment area. This is likely to mean the actual TPZ encroachment for Tree 1 will far less than that calculated as per AS4970–2009. TPZ encroachment for Trees A and B has been considered as per the supplied Preliminary Design Response and only Tree A may be affected. The encroachment is ‘minor’ and as per AS4970–2009 is therefore acceptable. Given the above, the following recommendations provide advice on the establishment of TPZs’ within the subject land of 1 George Street, Parkside formerly Caramar Clinic 179 Greenhill Road, for Trees 1, A and B as well as supporting the removal of the Tree 2.




Recommendations

The following recommendations are made in relation to the management of Trees 1, A and B:-

Root Zone Management

1. Appoint a Project Arborist.

2. Delineate a Tree Protection Zone (TPZ) on site around the tree equivalent to the radius listed within the Observations for the relevant trees; the TPZ includes both the below and above ground parts of the tree.

3. Erect a protective fence around the TPZ to prevent unauthorised entry, ensure the area is clearly signed TREE PROTECTION ZONE - NO ENTRY. The fence must be constructed with sturdy temporary fencing, 1.5-2 metres high.

4. All excavation within any TPZ is to be completed using non-destructive techniques such as HydroVac or hand digging.

5. Where roots are encountered the Project Arborist is to determine the significance of the root to tree health and treat accordingly i.e. prune, remove the root or offer suitable design alternatives.

Note: Following non-destructive investigation and assessment by the Project Arborist, it is expected the TPZ fence for Tree 1 can be reset to a 9.00 metre radius. (See Appendix B)

6. Decompact the soil within the TPZs’ and treat the grass in the area with a suitable glyphosate, or similar, based herbicide.

7. Apply a layer of composted mulch 75-100 mm deep over the available TPZs’ (spread by hand - do not use machinery to spread mulch within TPZs’ as this will compact the soil and reduce tree health and vigour) omit mulch from direct contact with the trunk.

8. Install an irrigation system within the on site TPZ of Tree 1 to dispense an additional 300-400 litres of water per week and within the on site TPZs’ of Trees A and B to dispense an additional 200-300 litres of water per week for the duration of the project.

9. Services to the development and any building including but not limited to Water, Gas, Electricity, Sewer, Telephone and Storm Water must be located as much as reasonably possible outside of the TPZs’ to minimise any encroachment into these areas and provide adequate protection to tree roots. If this is not possible, alternative and non-destructive excavation techniques should be utilised for their installation.

10. The construction of any driveways, pathways and sealed surfacing within any TPZ area must incorporate pervious materials above the existing grade with no compaction to the existing soil areas within the Tree Protection Zone. An example of such systems has been included within Appendix E - Paving Construction within a Tree Protection Zone. Gravel pathways are also acceptable.

11. Certificates of compliance should be attained from the Project Arborist at specified development intervals as outlined within Appendix F - AS4970-2009 Schedule of Compliance Checks.

Removal of Tree 2 is recommended for the following reasons:-




The tree is poorly structured and branch failure is expected to be ongoing. Remedial measures to prolong the ULE are limited. The tree is Exempt and achieves no further criteria of a tree worthy of retention. The above Root Zone Management recommendations are designed to reduce the risks associated with the subject tree and development impacts and should be conducted by or under the supervision of the Project Arborist. These management options will maintain the trees worthy of retention (Trees 1, A and B) in a sustainable manner that is unlikely to result in ongoing management concerns. Whilst I am hesitant to recommend removal of established trees, it is my opinion that complete removal of Tree 2 is the best management option in this instance. Appropriate replacement planting schemes are recommended to maintain the aesthetic and environmental attributes within the local area. Thank you for the opportunity to provide this report. Should you have any questions or require further information, please contact me and I will be happy to be of assistance. Yours sincerely

DANIEL TUCKWELL Consulting Arboriculturist Advanced Certificate in Arboriculture Tree Risk Assessment Qualification (TRAQ)




Glossary

Size: approximate height and width of tree in metres. Age: identification of the maturity of the subject tree. Useful Life Expectancy: expected number of the years that the subject specimen will

remain alive and sound in its current location and/or continues to achieve the relevant Principles of Development Control.

Current health of tree: visual assessment of tree health. Structure: visual assessment of tree structure. Circumference: trunk circumference measured at one metre above ground

level. This measurement is used to determine the status of the tree in relation to the Development Act 1993.

Diameter at Breast Height (DBH): trunk diameter measured at 1.4 metres above ground level

used to determine the Tree Protection Zone as described in Australian Standard AS4970-2009 Protection of trees on development sites.

Diameter at Root Buttress (DRB): trunk diameter measured just above the root buttress as

described in Australian Standard AS4970-2009 Protection of trees on development sites and is used to determine the Structural Root Zone.

Tree Protection Zone: area of root zone that should be protected to prevent

substantial damage to the tree’s health. Structural Root Zone: calculated area within the tree’s root zone that is considered

essential to maintain tree stability. Root Buttressing: area of root development as it joins to the trunk base. Project Arborist A person with the responsibility for carrying out a tree

assessment, report preparation, consultation with designers, specifying tree protection measures, monitoring and certification. The project arborist must be suitable competent in arboriculture, having acquired through training, experience, the knowledge and skills enabling that person to perform the tasks required by this standard.




References

Australian Standard AS4373–2007 Pruning of amenity trees: Standards Australia.

Australian Standard AS4970–2009 Protection of trees on development sites: Standards Australia.

Matheny N. Clark J. 1998: Trees and Development a Technical Guide to Preservation of Trees During Land Development: International Society of Arboriculture, Champaign, Illinois, USA.

Matheny N. Clark J. 1994: Evaluation of Hazard Trees in Urban Areas: International Society of Arboriculture, Champaign, Illinois, USA. Julius A. Kocher W. Liefheit K. Lilly S. et al 2013: Tree Risk Assessment Qualification: International Society of Arboriculture, Champaign, Illinois, USA. Keane P.J. Kile G.D. Podger F.D. Brown B.N. 2000: Diseases and Pathogens of Eucalypts: CSIRO Publishing, 150 Oxford Street, Collingwood, Victoria 3066 Australia

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Appendix A – Tree Location

Tree A

Subject Land

Tree 2

Tree 1

Tree B




Appendix B – Tree Protection Zones

Tree 1

Tree A

Tree B

TPZ 15.00 metres Following non-destructive investigation may be reset to;

TPZ 9.00 metres

These TPZs’ were averaged to 9.72 metres




Appendix C – Preliminary Design Response, November 2015 – Tree 1

Basement Level

Ground Floor Plan




Appendix D – SK-04-10015 Basement Floor Plan, SK-05-10015 Ground Level Floor

Plan, 23 May 2016 – Tree 1

Basement Level

Ground Floor Plan

14.90% TPZ

Encroachment

14.90% TPZ Encroachment

This area can be constructed as per Points 9 and 10 within

the Recommendations




Appendix E – Paving Construction within a Tree Protection Zone

Paving within any Tree Protection Zone (TPZ) must be carried out above natural ground level unless it can be shown with non-destructive excavation (HydroVac or hand digging) that no or insignificant root growth occupies the proposed construction area. Due to the adverse effect filling over a Tree Protection Zone (TPZ) can have on tree health; alternative mediums other than soil must be used. Available alternative mediums include structural soils or the use of a cellular confinement system such as Ecocell®. Ecocell® Ecocell® systems are a cellular confinement system that can be filled with large particle sized gravels as a sub-base for paving systems to reduce compaction to the existing grade. Site preparation Clearly outline to all contracting staff entering the site the purpose of the TPZ’s and the

contractors’ responsibilities. No fence is to be moved and no person or machinery is to access the TPZ’s without consent from the Project Arborist.

Fence off the unaffected area of the TPZ with a temporary fence leaving a 1.5 metre gap

between the work area and the fence; this will prevent machinery access to the remaining root zone.

Installation of Ecocell® and EcoTrihex Paving® Install a non-woven geotextile fabric for drainage and separation from sub base with a minimum

of 600mm overlap on all fabric seams as required. Add Ecocell®, fill compartments with gravel and compact to desired compaction rate. If excessive groundwater is expected incorporate an appropriate drainage system within the

bedding sand level. Add paving sand to required depth and compact to paving manufacturer’s specifications. Lay EcoTrihex Paving® as per manufactures specifications and fill gaps between pavers with

no fines gravel.

Remove all debris, vegetation cover and unacceptable in-situ soils. No excavation or soil level change of the sub base is allowable for the installation of the paving.

Where the finished soil level is uneven, gullies shall be filled with 20 millimetre coarse gravel to

achieve the desired level.







Appendix F - AS4970-2009 Schedule of Compliance checks







Documents

Tree Report ATS311-001GeoStAmd€¦ · Arborman Tree Solutions Pty Ltd – Professionals in Arboriculture Phone: (08) 8240 5555 23 Aberdeen Street ATS3611-001GeoStAmd – 27 May 2016