Chan v So

Catchwords: TREES (DISPUTES BETWEEN NEIGHBOURS) –compromised tree overhanging applicants’ land – nuisance caused by falling debris – wall damaged by tree – apprehension of additional damage and risk of injury – parties agree to tree removal

Legislation Cited: Dividing Fences Act 1991 (NSW), s 13A
Trees (Disputes between Neighbours) Act 2006 (NSW), Pt 2, s 6, 7, 8, 9, 10, 12

Cases Cited: Barker v Kyriakides [2007] NSWLEC 292
Lewis v Tilney [2009] NSWLEC 1042
McPherson v Lake [2017] NSWLEC 1081
Yang v Scerri [2007] NSWLEC 592

Texts Cited: AS 4373:2007, Pruning of amenity trees
Expert Witness Code of Conduct, NSW Uniform Civil Procedure Rules, 2005
Safe Work Australia, ‘Guide to managing risks of tree trimming and removal work’, 2016

Category: Principal judgment

Parties: Wai Chan (First Applicant)
Ming Zeng (Second Applicant)
Yick So (First Respondent)
Ringo Lai (Second Respondent)
Mark Crewe (Third Respondent)
Jasmine Crewe (Fourth Respondent)

Representation: Counsel:
Mr Chan (Self-represented) (First Applicant)
Ms Zeng (Self-represented) (Second Applicant)
Mr J Clifton (First and Second Respondents)
Mr Crewe (Self-represented) (Third and Fourth Respondents)
Solicitor:
Raymond Lee & Co (First and Second Respondents)

File Number(s): 24/410511

Publication restriction: Nil

Judgment

Background

1. COMMISSIONER: Mr Chan and Ms Zeng (the applicants) have lived at their South Turramurra property since 2008, where they share a long north-south side boundary with 2 adjoining neighbours. The northern section of the boundary adjoining the applicants’ front yard was shared with the corner block of Mr So and Ms Lai (the First and Second respondents). The southern, back section of the applicants’ side boundary was shared with Mr So and Ms Lai’s side neighbours, Mr and Mrs Crewe (Third and Fourth respondents).

2. The properties of Mr So and Ms Lai, and the Crewe’s both sloped downhill towards the applicants’ land, which had been excavated to provide level ground for their dwelling and an inground swimming pool in the applicants’ back yard.

3. The applicants’ common boundary with the First and Second respondents was delineated by an old wire fence and an informal hedge with various species of shrubs and small trees, primarily on the First and Second respondents’ side. Between the applicants’ and the Crewe’s properties, the boundary was defined by a single skin brick wall (the wall), about 1.4 metres (m) tall.

4. The wall appeared quite imposing when viewed from the applicants’ land, as it had been constructed on a narrow terrace, about 1.0m higher than the level of the adjacent swimming pool.

5. A mature Magenta Lilly Pilly (Syzygium paniculat**um) (T1) was growing in the back corner of Mr So and Ms Lai’s land near the intersection of the 3 properties. The base of T1 was very close to the northern end of the wall.

6. The applicants contended that roots growing into their property between and under bricks at the wall’s base were from T1. They claimed T1’s roots were lifting the wall, causing it to lean, and had caused a long vertical crack about 6m south of T1, plus damage to other structures. The applicants said debris falling from overhanging branches of T1 caused roof damage to their dwelling and a heavy maintenance burden. Therefore, the applicants requested the respondents remove T1.

7. The applicants also contended that T2, which comprised 6 trees within the First and Second respondent’s hedge near the northern end of the common boundary, had grown into the applicants’ electricity service wires (the wires) and were causing risk of injury. The applicants wanted T2 pruned at least 0.5m clear of the wires and maintained in perpetuity at least 0.5m clear of the wires.

8. The applicants claimed to have sought removal of T1 since early 2022 via conversations with the First and Second respondents, by WhatsApp messages, and engaged in mediation through a Community Justice Centre, without reaching a resolution.

9. Consequently, on 5 November 2024, Mr Chan and Ms Zeng applied to the Court, pursuant to s 7 to Pt 2 of the Trees (Disputes Between Neighbours) Act 2006 (NSW) (the Trees Act), seeking orders for the First and Second respondents, at their expense, to remove T1 and prune T2, and for fair compensation for damage caused by T1.

The first onsite hearing

10. An initial onsite hearing took place on 29 January 2025. The applicants were self-represented while the First and Second respondents were represented by Mr Clifton of Counsel and Mr Lee, Solicitor. The Court inspected the trees, the walls, PVC pipes and other structures prior to hearing submissions from the parties.

The applicants’ position

11. Damage: Mr Chan and Ms Zeng submitted that T1 had caused, and was causing damage to their property, and presented risk of injury. Their concerns were detailed in their application Form H (Exhibit B) and supported by a range of photographs.

12. The applicants contended T1 was about 13-14m tall with a crown spread of similar dimensions. They estimated T1 was 40-50 years old with a trunk diameter at breast height (DBH) of approximately 0.6-0.8m. Alleged structural defects comprised basal damage, narrow forks with included bark, and dieback in the upper canopy.

13. Mr Chan and Ms Zeng contended the tree was in an unsuitable location near the intersection of the three properties, as it was exerting pressure on both the wall and the respondents’ common timber boundary fence and was overhanging the applicants’ land. The applicants claimed roots of T1 had lifted, displaced and cracked the wall. They noted a near vertical crack extending the full height of the wall about 6m south of T1 and a horizontal crack about 25 millimetres (mm) wide and more than 2m long near a root growing through mortar between two courses of bricks near the base of the wall, close to T1.

14. Additionally, the applicants claimed roots from T1 had damaged sandstone retaining walls east of a path beside their dwelling and beside stairs and other gardens, had lifted pavers, and cracked a concrete slab. They said roots were visible in many areas of their property, including against the footing of the dwelling wall and Mr Chan indicated small roots he had exposed under the dwelling, which he alleged were from T1.

15. The applicants noted the trunk of T1 was about 4m away from the external wall of their main bedroom and said T1’s canopy overhung the roof of the main bedroom. They claimed about 45% of T1’s canopy overhung their land, and most of the overhanging branches were dead. They claimed falling branches had damaged roof tiles and were likely to cause further tile damage in the future. While they conceded this could be remedied by canopy pruning, the applicants contended that pruning would not prevent further damage caused by T1’s roots.

16. In Exhibit B, at p 14-23, the applicants submitted argument and photographs of damage to the wall, the sandstone retaining walls, a concrete slab, and a PVC drainage pipe. Mr Chan contended that T1 was the primary cause of damage to the entire wall and that deflection of the top of wall towards his property and the bottom towards the Crewe’s resulted from pressure and uplift from T1’s roots. He rebuked alternative causes of damage contented by the First and Second respondents as less significant, at best.

17. The applicants attributed cracking of stone and mortar of the sandstone walls to pressure exerted by adjacent roots of T1, notwithstanding they acknowledged “T1’s root system and its proximity to this wall are not the only factors contributing to the (sandstone) walls’ poor condition”.

18. The applicants contended that debris from T1’s overhanging branches had continuously filled roof gutters and caused flooding within the dwelling. They claimed the maintenance burden to clear the roof and flowers and fruit falling and blowing into their swimming pool and onto outdoor surfaces was excessive, relative to the extent of reasonable maintenance contemplated in the Tree Dispute Principle established in Barker v Kyriakides [2007] NSWLEC 292 (Barker*)*.

19. Risk of injury to persons: Mr Chan and Ms Zeng contended that T1’s multi trunked form, tight branch forks and included bark, and fungal decay in the lower trunk, caused weaknesses which increased the likelihood of branch failure. The applicants claimed trunk strength was also reduced by borers feeding on dead tissue and causing cavities. They alleged that fruit from T1 which fell constantly in summer, presented a high risk of injury from slipping and that such injury had already occurred. Dead branches falling on the roof and outdoor recreation areas were also said to be likely causes of injury, as was the wall toppling into the applicants’ back yard due to its lean and unstable foundations. Mr Chan also noted “sinus issues” caused by flowers of T1.

20. The applicants contended T2 presented risk of injury to persons because the 6 trees had grown close to the applicants’ wires. They proposed ongoing pruning by a professional contractor, at the First and Second respondents’ expense, to maintain clearance of at least 0.5m between T2 and the service wires.

21. The applicants*’ (summarised) proposed orders*:

22. The First and Second respondents shall engage and pay a qualified contractor to prune T2 at least 0.5m clear of the applicants’ electricity service wires and always maintain such clearance. The works shall include removal of all tree debris from site.

23. The First and Second respondents shall engage and pay a qualified contractor to remove T1 to near ground level and grind or poison the stump to prevent regrowth within 2 months of the date of these orders. The works shall include removal of all tree debris from the site. Should T1 be replaced, such replanting shall be at least 2m from any common boundary.

24. The First and Second respondents shall contribute to like-for-like rectification of the wall.

25. If removal of T1 is not ordered, the First and Second respondents shall prune overhanging branches, remove roots of T1 causing damage, install a concrete block root barrier on the common boundary, conduct defect assessment including internal diagnostic decay testing on T1, with a report, conduct biennial aerial inspection and internal diagnostic decay testing of T1, and repair sandstone wall and concrete slab damage, all at the First and Second respondents’ expense. The First and Second respondents shall take responsibility for any existing or future damage to the applicants’ property, or personal injury due to T1.

The respondents’ position

22. Mr So and Ms Lai based their submissions on reports from Mr Williams of Urban Arbor (arborist report), dated 20 January 2025, and from Mr Dockrill of Izzat Consulting Engineers (engineering report), dated 28 January 2025. The report authors were appropriately qualified in their fields of expertise. Both acknowledged and agreed to be bound by the requirements of the Expert Witness Code of Conduct, contained in Schedule 7 of the Uniform Civil Procedure Rule 2005 (UCPR). Additionally, Mr Williams noted compliance with the Court’s Practice Note, Division 2 of Part 31 of the UCPR. Both reports were of a high standard and assisted the Court.

23. Arborist report: Summarised key findings of the arborist report included, T1 was approx. 10m tall with a canopy spread of approx. 8m. About 0.4m above ground level, T1’s trunk divided into 2 main stems. The larger stem (Stem 1) grew towards west-northwest over the applicants’ gardens, paths, and dwelling.

24. About 1.5 to 2 m above ground level, Stem 1 divided at a codominant junction comprising 6 stems. One of the 6 stems was dead, while another had dieback from the tips and was about 60 to 70% dead. The dead branches were more brittle and prone to fungal decay and failure than live branches, and such failure would result in the branches falling onto the applicants’ gardens, paths, or dwelling roof. Pruning of the dead and declining branches would remove 20 to 30% of T1’s overall canopy area and modify its shape.

25. Between ground level and the codominant junction about 1.5 to 2m above ground level, the northern side of Stem 1 was extensively wounded. Mr Williams opined the wounding was probably caused in the distant past by the failure of another stem about 2 metres above ground level. The trunk appeared to display advanced fungal decay which was likely to extend upwards into the 6-stem codominant junction, but internal diagnostic testing would be required to clarify the extent of decay penetration and accurate assessment of the trunk’s structural integrity.

26. Therefore, Mr Williams recommended removal of Stem 1 at the minimum, due to the high likelihood of breakage and because of dead branches comprising about 20 to 30% of the canopy overhanging the applicants’ garden, paths, and dwelling roof. Due to the proximity of T1’s roots to the wall, the wall damage allegedly caused by T1’s roots, and because of indications T1’s health and vigour was declining, Mr Williams recommended removal of T1.

27. D**amage caused by T1: Mr Williams investigated roots near the northern end of the wall, which was less than 200mm from T1’s trunk. One root with a diameter of about 150mm was located below the footing of the wall but was not contacting the wall. It appeared to be crushing a PVC pipe near the top of a brick drainage pit. Two roots about 40mm diameter and another about 25mm high, all “appear to be growing below the footing of the wall” … “and are in direct contact with the wall footing”. Based on their characteristic bark, location, and direction, Mr Williams concluded that all 4 roots belonged to T1 and the 25mm root displayed extensive broadened callus.

28. Mr Williams referenced Roberts et al (2006) from ‘Tree Roots in the Built Environment’, who said, “direct damage to heavy structures occurs infrequently in comparison to light structures such as retaining walls or buildings with poorly constructed foundations”. “Tree roots can distort around the foundations or footings after coming into contact, which can often lead to a build-up of roots against the footings of a structure in close proximity to a tree as the tree roots produce a swelling of callus growth from mechanical stimulus at the points of contact. The combined pressure of several roots together can cause significant damage to a structure.”

29. Mr Williams also quoted Biddle, from ‘Tree Root Damage To Buildings, volume 1’ (1998), who discussed how roots producing irregular callus growth “as a reaction to exposure to light, mechanical stimulus or minor injury”… “can often be far larger than the roots it is growing on, so that, on assumption that the cellular pressure it exerts is similar, the overall force produced by the callus may be far greater.”

30. Mr Williams recommended specialist advice be sought from a structural engineer to determine the nature of damage to the wall, the causes of the damage, where the wall’s footings are lifting or rotating, and which part/s of the tree are causing direct damage. He recommended the structural engineer also provide advice on options to repair the wall including identifying which roots need to be severed or if the trunk needs to be shaved to repair the wall.

31. Ri**sk of injury from Tree 2*:* Tree 2 comprised a group of 3 Viburnum shrubs and 3 small Privet trees within the respondents’ hedge beside the northern end of the common boundary. They had grown sufficiently so they touched the wires that hung low above the applicants’ lawn close to the common boundary. The Viburnums are considered as trees for the purpose of the Trees Act.

32. Although the applicants proposed regular pruning to maintain all 6 trees at least 0.5m clear of the wires, Mr Williams recommended pruning of the Viburnums as proposed, but removal of the Privet trees, due to their rapid growth rate and designation as an environmental weed. Privet trees produce copious viable seed, and these 3 trees would almost certainly have been self-sown.

33. Engineering report*:* In summary*,* Mr Dockrill acknowledged roots of T1 were a cause of damage to the wall but contended that damage caused by T1’s roots was limited to the initial 1.5m at the wall’s northern end. He opined that the stability of the wall was independently compromised from the outset due to the following wall construction inadequacies.

34. The wall was single brick with a double brick pillar at the northern end and at intervals of about 6m on the Crewe’s side of the wall. Mr Dockrill observed the wall was “built upon a combination of brick and stone footings with some concrete used, however this concrete was not consistent, and I would not consider the concrete as a footing, but more as a levelling material”.

35. Based on his structural engineering experience of some 30 years, Mr Dockrill said the brick fence was not originally built to a reasonable standard considering building practices at the time. Although Mr Dockrill did not expect a wall that appeared to have been built some decades ago to satisfy the current building standards, he said it ought to have been built to standards acceptable at the time of construction.

36. Up to 30 years ago, the minimum requirements for stability for masonry boundary fences would generally be double thickness of brick, or, depending on wall height, single bricks with stiffening piers typically at 1.8m spacings, or closer together.

37. Even if the wall was built 30 years ago, the fact that the wall was 1.4m high but had piers at approximately 6m spacing, indicated it was not built to a reasonable standard. The wall was too thin for its height to satisfy requirements for adequate general stability.

38. Mr Dockrill observed the site terrain included “some rock outcropping as well as clay”. As the footing of the wall was not consistently on rock, he expected some seasonal movement of the footing due to clay reactivity, which is a common phenomenon in Sydney. Clay reactivity is where the clay shrinks in periods of dry weather and expands during or after periods of wet weather. Due to the inconsistent foundation and footing system, Mr Dockrill expected seasonal differential movements for a wall of this construction.

39. A vertical crack on the southern side of the first intermediate pillar south of T1 (the pillar), about 6m from T1, extended the full height and thickness of the bricks. Mr Dockrill opined the crack was due to footing movement more likely caused by the effects of seasonal clay reactivity, rather than the impact of T1.

40. Mr Dockrill was not surprised that the crack had occurred directly adjacent to the pier, as this “is the line of reduced strength when comparing the pier to the single thickness of brick”. He opined that this cracking was a result of differential footing movement in this area more than 6m from T1.

41. The wall leant towards the applicants’ property at 41mm/m, 3-4m from T1 and 21 mm/m, 11.5m from T1 (Photos 13-16).

42. In his photos, Mr Dockrill identified roots from T1 growing under the wall but also noted clustered roots from a “large shrub” growing up the wall’s face north of the observed roots from T1 on the applicants’ land and growing extensively on surfaces of the sandstone walls.

43. The sandstone walls: Mr Dockrill observed cracking, “bulging or lateral deformation within the lower 1/3 of the (sandstone) wall”, which he said were characteristic symptoms of the back of retaining walls being subjected to increased hydrostatic forces due to absent, inadequate, or clogged sub surface drainage systems. However, Mr Dockrill acknowledged being unable to view behind the sandstone walls to clarify this contention.

44. Mr Dockrill submitted that walls of this type, constructed with randomly shaped sandstone flagging, usually taper in from about 300mm wide at the base to about 100mm single thickness at the top. He speculated that these sandstone walls failed to taper out to a sufficiently broad base but again acknowledged being unable to observe behind the walls to confirm or deny this.

45. He noted the “large shrub” growing up the wall and close to the boundary on the applicants’ land north of the wall, was also extensively covering the surfaces of the sandstone walls.

46. The respondents’ (summarised) proposed orders:

47. Pursuant to s 9(2)(e) and s 9(2)(f) of the Trees Act, the respondents, at their cost, shall remove T1 to near ground level within 2 months of the date of these orders.

48. Pursuant to s 9(1) and s 9(2)(g) of the Trees Act, the applicants shall allow the respondents and/or the respondents’ agents to access their property to remove T1 or to obtain quotations for the removal of T1, subject to the respondents providing the applicants 48 hours’ notice of intended entry.

49. Pursuant to s 9(1) of the Trees Act, the applicants shall permit access to their property by the respondents and/or the respondents’ agents to remove boundary fencing and any other objects and fixtures on the applicants’ land within 2 metres of the common boundary as necessary to remove T1, on the condition that any such fencing, objects and fixtures are replaced within a reasonable time after the tree removal, and subject to the respondents providing the applicants 48 hours’ notice of such intended access.

50. Pursuant to s 9(2)(e) and s 9(2)(f) of the Trees Act, the respondents, at their cost, shall prune or remove trees described as T2, to achieve a minimum clearance of 0.5m between T2 and the applicants’ overhead utility wires within 2 months of the date of these orders, and thereafter maintain a minimum clearance of 0.5m between T2 and the applicants’ overhead utility wires.

51. Pursuant to s 9(2)(g) of the Trees Act, the applicants shall allow the respondents and/or the respondents’ agents to access their property to initially prune or remove T2 to achieve a minimum clearance of 0.5m between T2 and the applicants’ overhead utility wires, and thereafter maintain such clearance between T2 and the applicants’ overhead utility wires, subject to the respondents providing the applicants 48 hours’ notice of intended entry.

52. All parties shall have liberty to apply to the Court on 3 days’ notice for any further or other orders that may reasonably be required to implement and give effect to these orders and notations.

53. The application is otherwise dismissed.

The jurisdictional framework

47. Relevant sections of Pt 2 of the Trees Act are set out below:

Part 2– trees that cause or are likely to cause damage or injury

7 Application to Court by affected land owner

An owner of land may apply to the Court for an order to remedy, restrain or prevent damage to property on the land, or to prevent injury to any person, as a consequence of a tree to which this Act applies that is situated on adjoining land.

…

9 Jurisdiction to make orders

(1) The Court may make such orders as it thinks fit to remedy, restrain or prevent damage to property, or to prevent injury to any person, as a consequence of the tree the subject of the application concerned.

(2) Without limiting the powers of the Court to make orders under subsection (1), an order made under that subsection may:

(a) require the taking of specified action to remedy damage to property, or

(b) require the taking of specified action to restrain or prevent damage or, if damage has already occurred, further damage, to property, or

(c) require the taking of specified action to prevent injury to any person, or

(d) require the making of an application to obtain any consent or other authorisation referred to in section 6 (1) (a), or

(e) authorise the applicant concerned to take specified action to remedy, restrain or prevent damage or (if damage has already occurred) further damage to property, or

(f) authorise the applicant concerned to take specified action to prevent injury to any person, or

(g) authorise land to be entered for the purposes of carrying out an order under this section (including for the purposes of obtaining quotations for the carrying out of work on the land), or

(h) require the payment of costs associated with carrying out an order under this section, or

(i) require the payment of compensation for damage to property, or

(j) require the replacement of a tree that the Court orders to be removed and for the new tree to be maintained to a mature growth.

48. Before making orders under Pt 2 of the Trees Act, the jurisdictional tests at s 10 must be met. The tests at s 10(2) are the most significant, requiring satisfaction the trees have caused, are causing, or are likely in the near future to cause, damage to the applicants’ property, or injury to a person.

49. 10 Matters of which Court must be satisfied before making an order

(1) The Court must not make an order under this Part unless it is satisfied:

(a) that the applicant has made a reasonable effort to reach agreement with the owner of the land on which the tree is situated, and

(b) if the requirement to give notice has not been waived, that the applicant has given notice of the application in accordance with section 8.

(2) The Court must not make an order under this Part unless it is satisfied that the tree concerned:

(a) has caused, is causing, or is likely in the near future to cause, damage to the applicant’s property, or

(b) is likely to cause injury to any person.

49. The Court must also consider matters at s 12 of the Trees Act before making any orders.

12 Matters to be considered by Court

Before determining an application made under this Part, the Court is to consider the following matters:

(a) the location of the tree concerned in relation to the boundary of the land on which the tree is situated and any premises,

(b) whether interference with the tree would, in the absence of section 6 (3), require any consent or other authorisation under the Environmental Planning and Assessment Act 1979 or the Heritage Act 1977 and, if so, whether any such consent or authorisation has been obtained,

(b1) whether interference with the trees would, in the absence of section 25 (t) (Legislative exclusions) of the Native Vegetation Act 2003, require approval under that Act,

(b2) the impact any pruning (including the maintenance of the tree at a certain height, width or shape) would have on the tree,

(b3) any contribution of the tree to privacy, landscaping, garden design, heritage values or protection from the sun, wind, noise, smells or smoke or the amenity of the land on which it is situated,

(c) whether the tree has any historical, cultural, social or scientific value,

(d) any contribution of the tree to the local ecosystem and biodiversity,

(e) any contribution of the tree to the natural landscape and scenic value of the land on which it is situated or the locality concerned,

(f) the intrinsic value of the tree to public amenity,

(g) any impact of the tree on soil stability, the water table or other natural features of the land or locality concerned,

(h) if the applicant alleges that the tree concerned has caused, is causing, or is likely in the near future to cause, damage to the applicant’s property:

(i) anything, other than the tree, that has contributed, or is contributing, to any such damage or likelihood of damage, including any act or omission by the applicant and the impact of any trees owned by the applicant, and

(ii) any steps taken by the applicant or the owner of the land on which the tree is situated to prevent or rectify any such damage,

(i) if the applicant alleges that the tree concerned is likely to cause injury to any person:

(i) anything, other than the tree, that has contributed, or is contributing, to any such likelihood, including any act or omission by the applicant and the impact of any trees owned by the applicant, and

(ii) any steps taken by the applicant or the owner of the land on which the tree is situated to prevent any such injury,

(j) such other matters as the Court considers relevant in the circumstances of the case.

Findings

The trees were situated on adjoining land

50. While minor parts of the flared base of T1 appeared to extend beyond common property boundaries, for the purpose of s 7, a tree is situated on adjoining land if it is located “wholly or principally” on a respondent’s land. Therefore, T1 unambiguously satisfied the requirements of s 7 of the Trees Act.

The applicants made a reasonable effort to reach agreement

51. The applicants provided evidence of attempts to resolve the dispute with the First and Second respondents since May 2022, by way of personal discussion, WhatsApp messages, and mediation through a Community Justice Centre. While their attempts were unsuccessful, I am satisfied that they amount to a reasonable effort to reach agreement with the First and Second respondents and thus engage s 10(1)(a). I am also satisfied that appropriate service and sufficient notice of the application was provided to engage s 10(1)(b) of the Trees Act.

The trees have damaged the applicants**’** property – s 10(2)(a)

52. With respect to the applicants’ claim of damage to the dwelling roof by falling overhanging dead branches, I found insufficient evidence of past or current damage. However, having observed such dead overhanging branches, I was satisfied that damage to the roof, albeit minor, was probable in the near future. In a guidance decision published in Yang v Scerri [2007] NSWLEC 592; at [14], as a rule of thumb, the ‘near future’ is deemed to be a period of 12 months from the date of the determination.

53. Consequently, s 10(2)(a) is satisfied, and the jurisdiction of the Trees Act is engaged.

54. Contrary to the applicants’ contention, I was not persuaded the maintenance burden due to T1 was greater than the reasonable maintenance expectation arising from the Tree Dispute Principle in Barker. This shall be addressed further under s 12 considerations.

The second onsite hearing

55. A second onsite hearing was held on 6 June 2025 after Mr and Mrs Crewe were joined to the proceedings as Third and Fourth respondents, due to their joint ownership of the wall with the applicants. The applicants primarily used the respondents’ arborist report to substantiate their Notice of Motion for Joinder, dated 5 May 2025. The applicants’ Grounds for Joinder were, a) Complete and Fair Determination, and b) Judicial Efficiency.

The wall

56. When inspected from the Crewe’s property, the upper section of wall protruded by little more than 1.0m, while the lower part acted as a retaining wall for the Crewe’s soil. A free-standing timber fence erected on metal posts within the Crewe’s back yard about 0.25m east of the wall, increased the effective height of the fence to about 1.8m.

57. With the added benefit of inspection from the Crewe’s back yard, the causes of wall damage became more obvious. For the first time, T1’s roots were visible between the tree and the wall. By comparison, visibility from the respondents’ land was sufficiently poor that the initial inspection provided little insight about the root/wall interface. Within the Crewe’s property, I inspected damage close to the tree at the wall’s northern end and around the continuous vertical crack adjacent the pillar about 6m from T1.

58. Near the wall’s intersection with the applicants’ rear boundary, distinct cracking and displacement was visible on the Crewe’s side that was otherwise concealed by vegetation on the applicants’ side of the wall. Mr Crewe’s had undertaken rough repairs towards limiting further damage. The Crewe’s backyard extended further south than the applicants’ such that the Crewe’s shared a continuation of the same wall with the applicants’ rear southern neighbour.

59. In Exhibit B, at p 8-16, and onsite, the applicants contended the uplift by T1’s roots and lean were particularly pronounced at the wall’s northern end near T1, but the roots of T1 were the primary cause of all wall damage to the southern end of their property. Mr Chan argued that the deflection of the top of the wall towards his property and of the bottom towards the Crewe’s aligned with forces from uplift by T1’s roots growing between and under brick courses at the wall’s base.

60. Regardless that Mr Chan provided a detailed and logical lay interpretation of forces causing wall damage, the applicants submitted no evidence from an engineer, nor evidence of possessing qualifications or experience relevant to interpretation of forces. I acknowledge and conditionally accept Mr Chan’s argument that expert evidence is often not required in the ‘relatively informal’ proceedings under the Trees Act. However, the interpretation of forces and the relative significance of possible causes of structural damage being contested in this case are accepted as requiring specialist knowledge typically confined to structural engineers and allied professionals. In this context, the applicants’ lay submissions, absent of such expertise, must be discounted.

61. Non expert submissions in areas accepted as requiring ‘expert knowledge’ would ordinarily be deemed as speculation or ‘possible’ causes of damage, relative to the evidence of the respondents’ engineer. Having said this, discounted submissions are not discarded submissions. They may merit further consideration and greater weight if they clearly align with ‘ground truth’ and are explicitly more plausible than alternative contentions.

62. Similarly, I bring no structural engineering qualifications to the Court but have accrued relevant expertise with retaining walls and their interaction with trees over more than four decades, from landscaping training and constructing DA approved brick retaining walls with reinforced concrete foundations, as a consultant arborist, in academic roles, and whilst determining wall/ tree conflicts at the Court, since 2017.

63. I was not persuaded by the applicants’ argument that roots of T1 caused damage for the wall’s full length to the applicants’ southern boundary, specifically to the section south of the vertical crack.

64. Mr Dockrill acknowledged that roots of T1 caused wall damage but contended such damage was limited to the initial 1.5m at the wall’s northern end. He opined that damage south of the northern 1.5m of the wall was caused by construction with single rather than double brick thickness, excessive distance between pillars, inadequate foundations on interspersed sandstone and clay, associated natural seasonal movement from reactive clays, and plant roots.

65. For the section south of the vertical crack, I prefer Mr Dockrill’s conclusions. I am satisfied that the vertical crack beside the pillar extended for the full height of the wall and effectively separated the wall into two discrete sections. Therefore, forces due to T1’s roots that may have impacted the wall’s northern section could not transfer southward beyond the crack. Consequently, I am satisfied that wall damage south of the crack was not caused by T1’s roots.

66. Instead, I was satisfied the damage to the southern section resulted from a combination of the causes advanced by Mr Dockrill, the single skin wall, excessive distance between pillars, inadequate foundations, natural movement from reactive clays, and roots of vines. Creeping fig vine (Ficus pumila) roots are renowned for causing damage amongst deteriorated structures and English ivy, the other vine on the wall, is usually less invasive but often causes similar damage.

67. North of the vertical crack, however, for the following reasons, I was not persuaded by Mr Dockrill’s opinion that damage caused by the roots of T1 was limited to the northern 1.5m of the wall.

68. Mr Williams had nominated three roots from T1 of 25-40mm diameter that “appear to be growing below the footing of the wall” … “and are in direct contact with the wall footing”. The root from T1 about 25mm thick was distorted and flattened, having developed a broad layer of callus during penetration through a layer of mortar (Exhibit B, p 14), one or two brick courses higher than the 40mm roots.

69. The root distortion and flattening were likely to have developed in response to compressive forces from the weight of the wall above the mortar layer the root was progressively penetrating and, at least initial strong resistance to penetration from solid compressed mortar. At some point the force exerted by the broadening, thickening root exceeded the combined strength of the mortar and gravitational force from the wall above the root such that the root caused a horizontal crack along the layer of mortar near the base of the wall. The horizontal crack had progressively broadened to about 25mm tall and more than 2m long.

70. At [28]-[29], I noted Mr Williams’ consideration of such broadened callus by Roberts and by Biddle, both renowned arboricultural authors. Biddle postulated about increased “overall force produced by the (broadened) callus”, “on assumption that the cellular pressure it exerts is similar” to a broader, larger root. Image 9 of the arborist report displayed the proximity of all 3 roots with the two 40mm diameter roots apparently under the wall one or two brick courses lower than the 25mm flattened root. Though the roots were not vertically aligned, they were sufficiently proximal to reasonably anticipate cumulative impact of uplift due to the 25mm root and at least one of the 40mm roots.

71. The northern section of the wall appeared to be in good condition with continuous intact mortar layers binding the courses of bricks. The wall appeared to function as a strong, rectangular unit. By virtue of the uplift within the long horizontal crack by the 25mm root, most of the northern section of the wall appeared detached from its foundations. Regardless that the wall was only single brick in width, it was about 1.3m tall above the long horizontal crack. Just like a rigid, tall, metal I beam, this wall height would result in considerable vertical strength and rigidity.

72. Radiant energy is captured by trees through photosynthesis to provide carbohydrates that power all biological processes. Sufficient energy transferred into extension growth of root tips and subsequent secondary growth in girth of T1’s (currently 25mm) root at the northern end of the wall to breach the mortar layer and gradually lift the wall and cause the long horizontal crack. Ordinarily, downward force from the wall’s weight under the influence of gravity would spread into and through the foundations and dissipate into the earth. In these changed circumstances where uplift from the root caused much of the northern wall section to be dis-attached from its foundations, the wall was subsequently suspended above the foundations. The force due to the wall’s weight under the influence of gravity bending the wall downward would put the wall under significant tension. Rather than being dissipated into the earth over a wide surface area of foundations, in keeping with the Law of Conservation of Energy, the total energy from the gravitational force would be transferred and focussed on the two points of attachment with the ground, which were the root causing uplift to the north and the first point of firm contact with foundations to the south. I am satisfied this southern point would have been the pillar and the crack occurred because of the necessary earthing of the transferred bending force.

73. The crack occurring down the line of relative wall weakness between the pillar and the wall was consistent with Mr Dockrill’s analysis but I am satisfied the crack was primarily a consequence of the force focussed at the pillar by the root uplift and the downward force on the suspended wall.

74. While this analysis may not be fully accurate in terms of physics, I am satisfied it is plausible and is largely consistent with the applicants’ contentions. Conversely, Mr Dockrill provided no reasoning nor any evidence to substantiate his opinion that damage caused by the roots of T1 was limited to the northern 1.5m of the wall. While such localised impact may be a reasonable assumption when a wall remains attached to foundations and energy can earth close to the force source, the circumstances here do not provide for that option.

75. Mr Dockrill opined that the cracking directly adjacent to the pillar was a result of differential footing movement (due to soil reactivity) in this area more than 6m from T1, as this “is the line of reduced strength when comparing the pier to the single thickness of brick”. However, the strength differential between the pier and the single skin wall would probably be reduced by the inadequate footings, noted by Mr Dockrill. Additionally, record high rainfall over the last 5 years has resulted in relatively consistent moisture levels in clays, which would likely reduce the impact of soil reactivity as a cause of wall movement during that period.

76. Consequently, I was more persuaded by the applicants’ argument that the three 25-40mm roots which had lifted the wall, were the primary cause of damage and rotation of the wall’s northern section up to and including the vertical crack at the pillar, rather than just the initial 1.5m as claimed by the respondents. I accept that differential footing movement arising from seasonal clay reactivity (28.5.2&3) may have predisposed the wall to the vertical cracking, but only to a minor extent.

77. On the balance of probability, I was persuaded by evidence adduced from the respondents’ arborist report and site observations which indicated that wall uplift caused by the cumulative impact of three 25-40 mm roots near T1 was the most likely primary cause of the vertical crack. The shape of the crack was consistent with this interpretation (Exhibit B, p 16). Therefore, s 10(2)(a) of the Trees Act is again satisfied.

The sandstone wall

78. I was not satisfied the applicants had proven T1 caused damage to the sandstone walls, notwithstanding the sandstone walls were badly damaged in various locations. Due to some displacement of stones and large cracks through stones and mortar, I could observe the back of some damaged walls along with their outer face.

79. Construction methods for the sandstone walls generally appeared inadequate. As noted by Mr Dockrill, walls about 1.2m high, like these, constructed with randomly shaped sandstone flagging, are usually about 300mm wide for the lowest 1/3rd then taper in to about 100mm thick at the top. Where I could observe the back of walls, they appeared to remain single stone thickness of about 100mm for their entire height. This may partly explain the cracking, “bulging or lateral deformation of the wall within the lower 1/3 of the wall”, noted in the engineering report.

80. Mr Dockrill contended that cracking, “bulging or lateral deformation of the wall within the lower 1/3 of the wall” was characteristic when the back of a retaining walls is subject to increased hydrostatic force due to inadequate or non-functioning sub surface drainage systems. Mr Dockrill was unable to confirm this hypothesis, but contended, at 30.4, that ineffective “drainage “is a common reason for retaining wall failure after 10 or more years”. The cracking, bulging and insufficient thickness within the lower 1/3 of the wall would also be likely to accelerate deterioration due to wear and tear. Conversely, Mr Chan highlighted the presence of weep holes at the base of the retaining walls to provide for drainage.

81. Most of the sandstone walls were covered in a dense mat of Creeping fig vine stems and leaves and roots were visible penetrating into fissures and eroded mortar. As noted above, the Creeping fig vine is renowned for causing damage to deteriorated structures, especially eroded, perished walls that roots readily penetrate. The roots in Photo 19 of the engineering report, labelled “appear to be from adjacent shrub within 88”, were the source of the extensive Creeping fig vine growth on the northern end of the wall. Copious established roots from this specimen also occupied the soil between the wall and the primary sandstone retaining wall beside the applicants’ side path. The extent of Creeping fig vine growth is illustrated in the engineering report at Photo 18 and Photos 26-32. An established Bougainvillea vine, which also have extensive roots, was also growing on the applicants’ property between the common boundary and a sandstone wall.

82. Although the applicants claimed the sandstone walls were being damaged by roots of T1, their evidence was inconclusive. The mere proximity of T1 is not sufficient basis for finding its roots are a cause of damage. As determined in Lewis v Tilney [2009] NSWLEC 1042; at [43] - [55], where there is ambiguity as to the source of roots, it is incumbent on applicants to identify the specific tree(s) on the respondents’ property that the applicants contend are the cause of the problem. This usually requires root tissue analysis or root DNA testing, which the applicants did not undertake. For all the reasons above, the applicants have failed to prove, on the balance of probability, that T1 caused damage to the sandstone walls.

The PVC pipe

83. The applicants claimed pressure exerted by a 150mm diameter root of T1 had damaged a PVC drainage pipe. At 28.6.2 of the engineering report, Mr Dockrill said, “I confirm that this is a PVC pipe which would convey water from a collection point to another pit or outlet. This is not a pipe that assists in any way to the drainage of either the brick wall or the sandstone wall. A drainage pipe effectively assisting the sandstone wall would be behind the sandstone wall and located close to the base”.

84. I conducted excavation around the PVC pipe section and concurred with Mr Dockrill. While the PVC pipe was probably damaged by T1, it appeared largely redundant and was not contributing to drainage or stormwater removal.

Cracked concrete

85. The applicants provided insufficient evidence to show that a hairline crack in concrete was caused by T1. Further, the hairline crack caused negligible impact on the function of the concrete slab and was insufficient damage to justify repair or replacement. Having said this, I appreciate that Mr Chan’s argument was influenced by the likelihood of the damage worsening if T1 was not removed.

The trees caused risk of injury to persons – s 10(2)(b)

86. When considering injury, the risk posed by a tree in the foreseeable future is primarily based on the characteristics of the tree, the history of any failures, any other relevant evidence, and the circumstances of the site at the time of the hearing (McPherson v Lake [2017] NSWLEC 1081; at [10]).

87. Though the applicants claimed risk of injury to persons arose from T1’s compromised structure, fallen fruit creating a slipping hazard, live branches tearing off in storms, “sinus issues” caused by flowers of T1, and dead branches falling on the dwelling roof and outdoor recreation areas, of these, only larger dead branches likely to fall on outdoor recreation areas cause sufficient risk to justify intervention.

88. I considered the structure of T1 to be insufficiently compromised to cause a genuine risk of major stem breakage in the foreseeable future. Risk arising from falling fruit could be removed or sufficiently reduced with reasonable maintenance and risk of injury from live branches impacting during storms is mitigated by ‘normal’ low occupation rates in outdoor areas during such storms. For the claimed risk of injury due to “sinus issues” caused by flowers of T1, Mr Chan failed to provide the required evidence including a statement from a doctor that complied with requirements of the Expert Witness Code of Conduct.

89. The dwelling’s roof structure would almost certainly protect dwelling occupants from injury due to the relatively small dead branches likely to fall on the roof and most of the dead branches likely to fall on outdoor recreation areas were relatively small and light. Nonetheless, there were sufficient larger dead branches likely to fall onto outdoor recreation areas in the foreseeable future to engage s 10(2)(b) of the Trees Act.

90. Key considerations when assessing risk are the likelihood of an occurrence and potential consequences that may result. In this light, I consider the primary risk of injury resulted from the instability of the wall due to construction inadequacies that has been exacerbated by wall uplift and twisting by the roots of T1. The wall was perched on inadequate foundations on a narrow terrace about 1m above the applicants’ closely adjacent swimming pool with a slight lean towards the applicants’ land. During warm weather, children are likely to occupy the pool for sustained periods.

91. Although I consider the likelihood of the wall falling to be very low to low, the consequences of such a failure may be catastrophic. Though this risk, therefore, is mathematically low, the potential consequences are so serious that mitigation is required.

92. Considering the following statement at 30.2 of the engineering report, Mr Dockrill appeared to have reached a similar conclusion, “It is my opinion that as a result of the inadequate construction of the brick wall as identified in 34.1, combined with what I believe are the now visible effects of those construction failings, including the vertical cracking and the lean inwards to the property at approx. 11.5m away from the Lilly Pilly (see Photos 15 and 16), the entire wall would now require replacement to ensure future stability and safety, even without the effect of tree T1.”

93. As to risk arising from branches of the 6 trees comprising T2 growing amongst the applicants’ wires, the First and Second respondents had pruned the trees comprising T2 prior to the second hearing of 6 June 2025 and provided the 0.5m clearance from the wires proposed by the applicants.

94. Orders shall be made for ongoing maintenance of the T2 trees by the respondents. I concur with Mr. Williams’ opinion that the three Privet trees are best removed whilst the three Viburnums will likely require regular pruning to maintain the 0.5m clearance from the wires.

Matters at s 12 of the Trees Act

95. I have considered all relevant matters at s 12 of the Trees Act. T1 contributes to the landscape value, privacy, and amenity of both the respondents’ and the applicants’ properties. It provides shading and cooling, but it is structurally and aesthetically compromised. The applicants deem it to be a nuisance. While T1’s appearance may be improved by deadwood pruning, its structural flaws, location next to the wall, and imperative to mitigate risk arising from T1’s contribution to wall destabilisation, inherently results in a short useful life expectancy. Consequently, an order for tree removal is the only viable and appropriate option. Both parties agreed that T1 tree should be removed at the respondents’ expense.

96. The First and Second respondents’ proposed order (3) for extensive access to the applicants’ land shall not be granted. The requested “removal of boundary fencing and any other objects and fixtures on the applicants’ land within 2 metres of the common boundary as necessary to remove T1” is unnecessarily disruptive. T1 is not a large tree and removal onto the respondents’ land should be well within the capacity of most suitably trained and experienced arborist crews. Access for debris removal through the respondents’ land is relatively straightforward, whereas the applicants’ sandstone walls appear very fragile.

97. Although T1’s removal would ordinarily require Council consent, such consent would likely be forthcoming if Council was presented with evidence from the arborist report. Nonetheless, as a consequence of s 6(3) of the Trees Act, explicit Council consent is not required.

98. The Court assesses many trees and groups of trees under the Trees Act. Relatively to many, this is not a large tree nor would the extent of branch encroachment beyond the common boundary be considered significant or extreme. While removal is justified and will be ordered, damage or injury resulting from T1’s overhanging branches would probably be minor. The dead branch the applicants submitted as an example likely to cause injury (Exhibit B, p 33) was said to be 2.3m long and appeared to have a diameter of about 10-20mm. 20mm diameter is the usual threshold applied by the Court when making orders for pruning. i.e. branches below 20mm are considered too small to reasonably be subject to Court orders.

99. Considering the limited size of the tree, the extent of overhanging foliage observed on site, and the fruit and flowers discussed in Exhibit B, I was not persuaded by the applicants’ claim that the maintenance burden was greater than would ordinarily apply in accordance with the Tree Dispute Principle in Barker. The circumstances here were not extraordinary and the maintenance expectation of Barker was reasonable. The debris could be maintained relatively quickly, efficiently, and quietly with a battery powered blower/ vacuum, which are readily available. Stamens blowing into the pool from flowers and fruit drop are limited to seasonal periods and it is likely that the tree preceded installation of the swimming pool.

100. The regular removal of leaves, dead sticks and other debris from the roof and gutters, which is specifically referenced in Barker, is similarly reasonable, particularly as T1 was now about 40-50 years old and its canopy would probably have already been close to the tree’s current proportions by the time it was about 30 years of age, when the applicants occupied the property in 2008. Thus, it is likely that T1’s canopy would have been overhanging the dwelling roof upon the applicants’ occupation, though not necessarily to the current extent.

101. As a result of the maintenance expectation arising in Barke**r, the applicants’ damage claim 7, regarding “Ceiling leaking and roof maintenance safety concern”, is dismissed. Although the applicants claimed to have undertaken “regular gutter maintenance and the installation of a gutter guard”, the area and volume of T1’s branches overhanging the roof, even allowing for debris blown onto the roof from branches not directly overhanging, was simply insufficient to cause an unreasonable maintenance burden. Therefore, abatement of the leaking ceiling reflects a requirement for more regular gutter clearing and/or repairs to prevent ingress of water.

102. The applicants were annoyed and frustrated by the First and Second respondents’ refusal to address their requests to prune or remove T1, while allegedly removing trees on their own property. However, there is no law per se or Council requirement for a tree owner to pay for or otherwise take responsibility for branches overhanging neighbouring properties or to offer “assistance in cleaning up the mess caused by T1 on (the applicants’) property” (Exhibit B, p 46).

103. Under the Trees Act, orders may be made when branches are proven to cause damage or present risk of injury, but no remedy is available for mere encroachment of branches over neighbouring land even when foliage, fruit or flowers fall from the tree. Neighbours generally resolve such issues by negotiation, and terms of arrangements vary. It is very rare, for example, for managing agents of rental properties to accept any financial responsibility for branches overhanging neighbouring land from ‘their owner’s’ properties. Alternatively, some tree owners conscientiously accept all responsibility, or neighbours may share the costs.

Conclusion

104. Based on extensive fragile deadwood on T1’s branches overhanging the applicants’ dwelling and outdoor recreation areas, I was satisfied T1 was likely to cause minor near future damage to the dwelling roof and present sufficient risk of injury to engage s 10(2) and justify intervention. I was also satisfied T1 had caused and was causing damage to the northern section of the wall and was the primary cause of the vertical crack. However, I was not persuaded by the applicants’ argument that the maintenance burden arising from debris from T1 falling into the dwelling’s gutters, the pool, or onto outdoor surfaces exceeded that ordinarily considered in Barker.

105. Mr Dockrill opined that T1’s root/s had damaged 1.5m of the wall closest to T1 but provided no reasoning or substantiation for this 1.5m threshold. Based on evidence adduced from the First and Second respondents’ arborist report, photos from the First and Second respondents’ engineering report, observation of the wall from both sides, and fundamental rules of physics, I was satisfied that three roots of T1 identified by Mr Williams had lifted the northern wall section for many metres towards the pillar and were the primary cause of the vertical crack at the pillar.

106. Specifically, I was satisfied that thickening of one 25mm broadened root that grew into the applicants’ property from T1 through mortar between brick courses at the base of the wall, had caused a long horizontal crack along the mortar course which lifted and separated the body of the wall from its foundations. The uplift and horizontal separation prevented gravitational forces from dissipating or earthing through the foundations close to the tree. Instead, the forces earthed at the pillar, probably the closest structure in firm contact with the ground, and the vertical crack primarily resulted from energy release consequent to the impact of the force at the pillar. Something had to give, thus the wall cracked vertically.

107. From the Crewe’s property, significant cracking and displacement was visible in the southern section of the wall near the intersection with the applicants’ rear wall, that was concealed by vegetation from the applicants’ side. Notwithstanding similarity to damage near the vertical crack, I was not satisfied that uplift by T1’s roots that primarily caused damage to the northern wall section caused damage to the wall south of the vertical crack because the vertical crack separated the two wall sections. Therefore, force transferred from wall uplift by T1’s roots could not transcend the vertical crack into the southern wall section.

108. I was instead satisfied that damage to the southern section was caused by a combination of the factors proposed by Mr Dockrill, the single skin wall, excessive distance between pillars, inadequate foundations, natural movement from reactive clays, and roots of vines, especially the roots of Creeping fig vine.

109. Although I was satisfied that uplift by roots of T1 was the primary cause of wall damage north of the vertical crack, and of the crack itself, I was nonetheless persuaded by Mr Dockrill’s submissions that the wall’s construction was inadequate, especially its foundations. Uplift by the roots of T1 was the primary cause of damage but the various causes proposed by Mr Dockrill predisposed the wall to damage.

110. Upon consideration of causes of damage, I therefore came to find it reasonable that the First and Second respondents incur partial financial responsibility for damage to the wall. However, they shall only pay for a portion of the cost of rectification of the wall’s northern section, in recognition that the roots of T1 were one of multiple causes of wall damage.

111. With respect to the applicants’ sandstone walls near their dwelling, the propensity for damage and likely accelerated deterioration due to wear and tear, was apparently impacted by the insufficient wall thickness and potential drainage inadequacies identified by Mr Dockrill. Though the applicants alleged T1’s roots were the primary cause of damage, there was a large Creeping fig vine climbing the wall near the common boundary and dense Creeping fig vine stems and foliage covering most of the sandstone walls. Where multiple sources of roots may be causing damage, root identification is required. The applicants did not undertake such root identification, thus this element of the application is refused.

112. A small PVC pipe section was probably damaged by T1, but the pipe appeared to be serving little purpose. Although the applicants provided insufficient evidence to prove that a hairline crack in a concrete slab was caused by T1, the hairline crack was not impacting the concrete’s function and was insufficient damage to justify intervention.

113. Section 10(2)(b) of the Trees Act was engaged by T1’s larger overhanging dead branches that were likely to fall in the foreseeable future onto the applicants’ outdoor recreation areas and by branches of T2 growing amongst the applicants’ wires, notwithstanding that in both cases, the risk was relatively low.

114. Risk associated with the underlying instability of the wall which was located on a narrow ledge about 1m above and about 1.5m distant from the end of the applicants’ swimming pool, was of considerable concern. I was satisfied the underlying risk from inadequate foundations and construction had been exacerbated by wall uplift by roots of T1 and the angle of a slight lean towards the applicants’ land, which was about double near the root uplift.

115. At 30.2 of the engineering report, Mr Dockrill was similarly concerned but largely confined his reasons to “the inadequate construction of the brick wall”. He said, “combined with what I believe are the now visible effects of those construction failings, including the vertical cracking and the lean inwards to the property at about 11.5m away from T1”, “the entire wall would now require replacement to ensure future stability and safety even without the effect of tree T1”.

116. Though there is no requirement for parties in procedures under the Trees Act to procure expert reports, given the onus is on the applicants to prove their case, it is common for applicants to submit a report when the case hinges on input of technical expertise such as structural engineering. The First and Second respondents submitted reports from a structural engineer and a consultant arborist that satisfied the Court’s requirements under the Expert Witness Code of Conduct.

117. In exhibit B, Mr Chan and Ms Zeng noted the likelihood the case would require the involvement of the Crewe’s because they jointly owned the boundary wall with the applicants. Considering the applicants’ prior awareness that the jointly owned wall would be a key subject of these proceedings, wall discussions with the Crewe’s prior to undertaking Court action would have been prudent. Such discussions would have provided an opportunity to jointly explore options and determine a plan of action with the Crewe’s, and perhaps avoid or reduce the added complexity caused by the Crewe’s belated addition to the proceedings.

118. The applicants did not submit a structural engineering report and, as events transpired, the absence of engineering advice and of prior wall discussions with the Crewe’s prevented the determination of wall risk reduction methods and satisfactory resolution of the case. Regardless that Mr Chan contended damage to the entire wall had been caused by T1, he was aware of the wall’s lean and instability and the resultant risk. Mr Chan had introduced and discussed this risk at the initial hearing. He had a copy of Mr Dockrill’s report, which included advice that the wall required “replacement to ensure future stability and safety.” Considering the potential catastrophic consequences of wall failure, however unlikely, this seemed reasonable advice.

119. Notwithstanding Mr Dockrill’s advice, Mr Chan strongly resisted this solution, primarily due to the cost, in favour of wall repair. However, in the absence of prior engineering advice, Mr Chan had no idea of repair options, specifications, costs, or whether repair was reasonably possible.

120. Considering these circumstances, I concurred with the First and Second respondents and Mr Crewe’s that the applicants should engage a structural engineer to clarify these issues so wall rectification decisions could be finalised. Given Mr Chan’s preference to repair the wall, it was obviously foreseeable that such information would be required, and the applicants had ample prior opportunity to procure such advice. Therefore, I was not prepared to adjourn the hearing while Mr Chan sought such engineering advice. Though Commissioners have no power to make orders for legal costs, had I adjourned, I considered an application for legal costs by the First and Second respondents would not have been unreasonable. The likelihood of a legal costs claim was confirmed by the respondents.

121. Although I was not satisfied that T1 had damaged the wall along its entire length, under the power provided by s 13A of the Dividing Fences Act 1991 (NSW), the Court can order fencing works for the entire length, given that T1 had damaged part of the wall. However, considering the circumstances that unfolded towards the conclusion of the proceedings, I am disinclined to do so. For the necessary repair or replacement of the wall section south of the vertical crack, there is no obvious reason why the applicants and the Crewe’s should not share the cost equally, but the applicants must first determine appropriate certified engineering solutions that mitigate risk and ensure future wall safety.

Orders

122. The Court orders that:

123. The respondents shall engage and pay Australian Qualification Framework (AQF) level 3 qualified arborists with all appropriate insurances (contractors) to remove T1 to near ground level and grind or poison the stump to prevent regrowth and remove debris via the respondents’ property, within 60 days of the date of these orders.

124. The respondents shall engage and pay contractors to remove or prune the trees comprising T2 sufficiently regularly to maintain clearance of at least 0.5m between the trees comprising T2 and the applicants’ electricity service wires at all times.

125. The applicants shall allow reasonable access for contractors to remove light branches and debris that inadvertently falls from T1 into the applicants’ property during removal of T1 and remove all pruning debris from T2 from the applicants’ property, upon receipt of at least 72 hours’ notice from the respondents.

126. All tree works shall comply with Safe Work Australia, ‘Guide to managing risks of tree trimming and removal work’, 2016, all pruning works shall also comply with AS 4373:2007, Pruning of amenity trees, and all works shall be completed during reasonable, daytime hours.

127. Within 45 days of the date of these orders, the applicants, at their expense, shall procure repair or replacement specifications for the section of the wall north of the vertical crack, produced and certified as a safe solution by a qualified, registered structural engineer, and distribute same to both respondent parties.

128. Within 90 days of the date of these orders, each party shall procure and exchange one quotation for repair or replacement of the wall north of the vertical crack from a licenced, insured builder (the builder), based on the certified specification from the structural engineer, and select one of the builders to undertake the wall works. If the parties cannot agree on a builder, the cheapest quotation shall be chosen.

129. The applicants shall engage and pay the selected builder to repair or replace the wall section north of the vertical crack per the structural engineer’s specifications. The wall works shall be completed within 270 days of the date of these orders. Within 7 days of completion, the applicants shall email the two respondent parties an itemised paid receipt for the wall works.

130. Within 7 days of receipt of the said itemised paid receipt, each of the respondent parties shall pay the applicants 1/3 of the total of the receipt by electronic funds transfer (EFT).

131. If the wall works are not completed within 270 days of the date of these orders, order (8) shall lapse.

J Douglas

Acting Commissioner of the Court

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