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[2026] NSWLEC 1136
General information, not legal advice.
Land and Environment Court (NSW)
2026-03-18
Galwey AC
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Source: NSW Caselaw (www.caselaw.nsw.gov.au). Converted to plain text by ZoeLaw. Not the official version.
Medium Neutral Citation: Armati v The Owners – Strata Plan No 15695 [2026] NSWLEC 1136
Hearing dates: 25 February 2026
Date of orders: 18 March 2026
Decision date: 18 March 2026
Class 2
Before: Galwey AC
Decision: See orders at [53]
Catchwords: TREES (DISPUTES BETWEEN NEIGHBOURS) — Pt 2 application — neighbouring tree — whether the tree has caused damage — whether the tree is likely to cause damage or injury — whether compensation should be paid — causal connection — contributing factors
Legislation Cited: Trees (Disputes Between Neighbours) Act 2006 (NSW), ss 7, 8, 9, 10, 12
Cases Cited: Smith v Zhang [2011] NSWLEC 29
Texts Cited: Australian Standard 4970:2025, Protection of trees on development sites (May 2025)
Inner West Tree Management Development Control Plan 2023
Safe Work Australia, Guide to managing risks of tree trimming and removal work (July 2016)
Category: Principal judgment
Parties: Sally Armati (First Applicant)
David De Coster (Second Applicant)
The Owners – Strata Plan No 15695 (Respondent)
Representation: Counsel:
S Armati (Self-represented) (First Applicant)
D De Coster (Self-represented) (Second Applicant)
K Harkness (Solicitor) (Respondent)
Solicitors:
K M Harkness & Co Solicitors (Respondent)
File Number(s): 2025/445563
Publication restriction: Nil
COMMISSIONER: On land in Rozelle belonging to The Owners – Strata Plan No 15695 (the Strata), the stem of a mature willow myrtle (Agonis flexuosa) (the tree) emerges from the ground next to the property’s southern boundary. The tree’s broad crown spreads to the south over the back yard of adjoining land owned by Sally Armati and David De Coster. For reasons explained below, Ms Armati and Mr De Coster have been asking the Strata to remove the tree since August 2024. The Strata would only agree to prune the tree.
Ms Armati and Mr De Coster have applied to the Court pursuant to s 7 of the Trees (Disputes Between Neighbours) Act 2006 (NSW) (the Trees Act) seeking orders for the Strata to remove the tree, for the Strata to pay the cost of remediation works to the dividing fence and to a retaining wall on their land, and for the costs associated with their application.
The Strata now maintains that, if the tree needs to be removed, it is due to actions on Ms Armati’s and Mr De Coster’s land, so they should pay the cost of its removal. They dispute Ms Armati’s and Mr De Coster’s compensation claims.
Ms Armati’s and Mr De Coster’s application (Exhibit A, filed 18 November 2025) includes Annexures A–H (various photographs, reports, correspondence, field notes, quotes and invoices). They subsequently filed additional information (Exhibit B, filed 3 February 2026) including a report and more photographs. They also provided a photograph of their retaining wall during construction (Exhibit C). The Strata provided a report from arborist Daniel Leonard (Exhibit 1), an affidavit sworn by Paul Foskett, a member of the Strata’s committee (Exhibit 2), and photographs (Exhibit 3).
The onsite hearing allowed the Court to inspect the tree and both properties. Ms Armati and Mr De Coster were self-represented. Mr Harkness represented the Strata with some additional information provide by Andrew Blenkinsopp, strata manager for the Strata. In addition to the evidence, I made observations of the tree and rely on my own arboricultural expertise and experience in making this decision.
10 Matters of which Court must be satisfied before making an order
(1) …
(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.
A brief timeline is helpful here.
The Strata’s buildings and landscape have existed here for many years.
Land at 79 Mansfield Street was subdivided some years ago to be developed as two properties (79 and 79A), each with a single dwelling.
Around late 2022 or early 2023 a retaining wall was constructed on 79A parallel to the common boundary shared with the Strata.
Around early 2023 a double-skin timber paling fence was installed on the common boundary between 79A and the Strata’s property at the expense of the developer or the future owner of 79A.
The development included excavation for and construction of in-ground swimming pools at 79 and 79A.
Ms Armati and Mr De Coster purchased the property with a completed dwelling at 79A in June 2024.
The retaining wall at 79A replaced a pre-existing retaining wall roughly in the same location. Ms Armati and Mr De Coster claim the tree’s roots have pushed against and displaced sections of the newer retaining wall. They submitted that the former retaining wall was removed by hand without causing damage to any tree roots. Photographs taken during construction of the newer retaining wall show no visible roots in the exposed area behind it, closer to the tree. Ms Armati and Mr De Coster suggested that the tree’s roots have grown since the retaining wall was replaced, and that roots and the soil around them move when the tree moves in the wind, causing some displacement of the retaining wall.
The Strata submitted that the burden of proof lies with Ms Armati and Mr De Coster, who have not provided any engineering evidence to support their claim. No excavation has been done to show that the tree’s roots have grown behind the wall and displaced it. If the tree has damaged the retaining wall, said the Strata, it could only be because the tree, which existed at the time, was not considered when designing the wall.
“View to South-west showing:
Old retaining wall was positioned immediately adjacent landfall.
New retaining wall is positioned further away from where the old wall was positioned and further away from boundary from where the old wall was located.
No excavation was required between old and new retaining wall.”
The willow myrtle is in the centre of the photograph. The photograph shows a gap between the new retaining wall and the soil supporting the tree. The caption suggests that the gap is a result of the removal, by hand, of the former retaining wall. Ms Armati and Mr De Coster obtained a quote from Stothard Projects in October 2025 to demolish and replace the retaining wall. Allowing for a brief period between them noticing the damage and obtaining a quote, the retaining wall’s displacement developed within 2.5 years of the date of the photograph above. While it is possible that roots grew into the area behind the new retaining wall after it was backfilled, I find it improbable that they would grow large enough within that period to displace the retaining wall. The growth rate of a willow myrtle, including its roots, is much slower than, say, a fig tree (Ficus sp.) or other fast-growing trees with more wide-spreading root systems.
The Strata submitted that the retaining wall appears thin and inadequate, questioning whether it was built to appropriate engineering specifications. Ms Armati and Mr De Coster might have provided the specifications and drawings for the retaining wall to demonstrate otherwise, but they have not. Based on observations alone, the retaining wall’s displacement, which seems relatively minor to me, is more likely a result of its inadequate design for the depth of ground it supports, rather than a result of tree root growth. Ms Armati and Mr De Coster have not shown otherwise. They have failed to demonstrate any causal nexus between the tree and the damage: see Smith & Hannaford v Zhang & Zhou [2011] NSWLEC 29 at [38]. I cannot be satisfied on the ‘preponderance of probability’ that the tree has caused damage to the retaining wall. For the same reasons, I cannot be satisfied that the tree is likely to cause damage to the wall in the near future. Pursuant to s 10(2) of the Trees Act, no orders can be made on this element of the application.
“1 x Agonis flexuosa (Willow Myrtle) located along the eastern [sic] boundary of the strata complex
Observations:
This tree is growing mostly over the neighbouring property and is essentially following the light provided by the space it is occupying. There were no defects observed with the root plate or main trunk. 2 first order branches were observed to have decay and borer damage.
Recommendations:
Remove both decayed limbs and monitor the tree. See photos.”
“Of greatest concern is the potential failure of a co-dominant stem.”
Ms Armati and Mr De Coster then engaged Rentokil to inspect their property and the tree. Toan Pham of Rentokil inspected the tree on 30 January 2026 and prepared a report. The report records evidence of borer activity in the tree, with supporting photographs, noting the moderate extent of damage was possibly caused by furniture beetle (Anobium punctatum). No termite activity was noted.
After receiving a copy of the tree dispute application, the Strata engaged Daniel Leonard, of Heartwood Tree Consulting, to inspect the tree on 10 February 2026. In his report of 13 February 2026, Mr Leonard described the willow myrtle as being 13 metres tall with a canopy spread of approximately 15 metres. Mr Leonard assessed the tree’s health as fair, but noted a slight reduction in its vigour since an earlier inspection he undertook in September 2024. He assessed the tree as being structurally poor due to fungal decay within its lower stem. After some discussion in his report about the impacts of development works at 79A on the tree’s roots, Mr Leonard estimated the tree’s useful life expectancy to be 5–10 years. Mr Leonard’s recommendations, summarised here, were:
That the timber paling fence be modified or rebuilt to give appropriate clearance between the fence and the tree to allow for the tree’s growth;
That further excavation near the tree be avoided;
That the condition of the tree’s stem, given the presence of basal decay, be monitored by an arborist annually; and
That any pruning be done by qualified arborists and in accordance with the appropriate standard.
Ms Armati and Mr De Coster submitted that the tree is in poor condition. Its health is poor and has been declining for years, so it is clearly not about to improve. Its stem and branches are affected by fungal decay and borers. It is structurally unsound, as described by Mr Hill, and poses a risk to them, to others on their property, and to their property including the fence, pool and outdoor furniture.
The Strata submitted that it relies substantially on Mr Leonard’s report in these proceedings. Mr Harkness said the Strata was not wedded to whether the tree should be retained or removed, which is a matter for the Court. The Strata only says that, if the tree must go, Ms Armati and Mr De Coster should pay for its removal. They rely on Mr Leonard’s report to support this submission.
I observed that the tree leans to the south with almost all of its crown over Ms Armati’s and Mr De Coster’s property. The basal stem divides into two stems just above ground level. The union between the two main stems is narrow with bark present within the union. The stems appear to have separated slightly, leaving a narrow opening within the union. Reaction wood – a response to relatively greater stresses in the outer layer of stems and branches as their cells divide – is present on the stems each side of the union. Not only is this stem union a significant structural defect within the tree, but it also likely explains the extent of pressure that one of these stems exerts on the top of the paling fence, which is greater than might be expected by growth alone over a period of less than three years. It is therefore surprising that Daniel Heartwood (of Aura Tree Services, not to be confused with Daniel Leonard of Heartwood Tree Consulting) wrote: “There were no defects observed with the …main trunk.” Equally surprising is that Daniel Leonard noted basal decay but not the weak stem union. The combination of decay and a weak stem union only increases the likelihood of stem failure. Kyle Hill’s conclusion – that failure of the codominant stem is the greatest concern – more accurately describes the situation as I saw it.
I conclude that the basal stem union has already begun to fail, contributing to the gradual dropping of the southern stem and the pressure it now exerts on the paling fence. Mr Leonard has, I think, overestimated the tree’s useful life expectancy at 5–10 years. But even if he were right, such a limited life expectancy would not warrant spending the money necessary to modify the fence further, monitor the tree annually, and carry out any pruning required to mitigate the risk.
Because the tree’s basal stem union has begun to fail, I find it likely that a large stem is likely to fail in the near future onto Ms Armati’s and Mr De Coster’s property causing considerable damage to their fence, pool and outdoor furniture, and possibly injuring somebody. Pursuant to s 10(2) of the Trees Act, the Court can make orders on this element of the application.
As set out above, the Court can make orders in these proceedings to remedy damage to the dividing fence and to prevent damage to Ms Armati’s and Mr De Coster’s property and injury to a person. The Court is to consider matters at s 12 of the Trees Act before making orders. Relevant matters are considered below.
The tree is close to the common boundary (s 12(a) of the Trees Act). At ground level its stem is against the dividing fence. A stem leans on the top of the dividing fence. The tree’s crown is almost entirely over Ms Armati’s and Mr De Coster’s property.
Interfering with the tree would require consent from Inner West Council (Council) (s 12(b)). The willow myrtle falls within the definition of a prescribed tree at Control C2 of the Inner West Tree Management Development Control Plan 2023 (the DCP). The Strata’s land is within The Valley Heritage Conservation Area. Therefore, according to Control C4 of the DCP, a development application is required to remove the tree or to prune more than 10% of its canopy. The Strata lodged a development application with Council for pruning the tree, was granted consent to prune the tree, and engaged Aura Tree Services to carry out the pruning. No application has been made for consent to remove the tree. When approving tree removal, it is usual for Council to require the planting of a replacement tree as a condition of the consent. If tree removal is to be ordered here, orders will include planting another tree.
The tree would tolerate some minor pruning (s 12(b2)); however, minor pruning would not sufficiently reduce the likelihood of tree failure causing damage or injury.
The tree makes some positive contribution to the Strata’s landscaping (s 12(b3)), while most of its shading and cooling benefits fall on Ms Armati’s and Mr De Coster’s property.
The tree has no historical, cultural, social or scientific value (s 12(c)); it is not indigenous to the area and contributes little to the local ecosystem and biodiversity (s 12(d)); its position on the Strata’s land limits its contribution to the natural landscape and scenic value of the land and surrounds (s 12(e)); it contributes little to public amenity (s 12(f)); and it does not appear to impact soil stability, the water table or other natural features of the land or locality (s 12(g)).
First, I consider factors that possibly contributed to the fence damage. The parties appeared to agree that some remediation to the fence is required. The tree was there when the developer of 79A constructed the double-skin paling fence right next to it. The fence included a cut-out at its top, around the tree’s stem, to allow for the tree’s growth.
Ms Armati and Mr De Coster submitted that it is only the tree that has caused damage to the fence. The tree’s decline and its risk to people and property have been apparent for years. If the Strata had removed it as requested, which was reasonable to expect, the fence would not have been damaged. Ms Armati and Mr De Coster said the Strata should therefore pay for remediation to the fence.
The Strata submitted that the clearance around the fence’s cut-out was inadequate for the tree’s growth. The Strata was not consulted on the fence’s design, nor asked to contribute to its design and construction in any way (Exhibit 2). The Strata submitted that the cost of any remediation to the fence must therefore lie with Ms Armati and Mr De Coster.
Neither party’s submissions seem unreasonable. Some allowance was made for the tree when the fence was constructed (although damage to the fence is not only a result of tree growth: see above at [25], [26]). The Strata acted on professional advice they obtained from Aura Tree Services, recommending that the tree be pruned rather than removed. Neither party should solely bear responsibility for the current situation by their acts or omissions. As a result, it seems only reasonable that they contribute equally to the cost of any remediation to the fence, so the orders will include equal financial contribution for fencing works. Ms Armati and Mr De Coster submitted that they would prefer to organise and control the fencing works, so orders will allow for this, with the Strata to reimburse them half the cost of the works.
Second, I consider factors that possibly contributed to the tree’s condition and the need for its removal. The parties have strong and opposing views on this.
Ms Armati and Mr De Coster submitted that the tree has been declining for years and is structurally weak. This alone has led to the need for its removal, so the Strata should pay the cost of tree removal works.
The Strata submitted that works at 79 and 79A have made the tree unstable and led to the need for its removal, so Ms Armati and Mr De Coster should pay the cost of tree removal works. The Strata relies on Mr Leonard’s report to support this submission.
The Strata submitted that the original development applications at 79 and 79A did not include swimming pools. The arboricultural impact assessment that accompanied the application, and was assessed by Council, showed that works would encroach into only 13% of the willow myrtle’s tree protection zone (TPZ). A modified development application including a swimming pool on each property was approved by Council. However, the Strata submitted that the impacts of the additional works to the tree were not assessed in an arboricultural impact assessment and Council did not consider the additional impacts when approving the modification. Mr Leonard estimated that the approved and completed works encroached into approximately 28% of the willow myrtle’s TPZ. He wrote on p 7 of his report:
“Excavation within this proximity likely resulted in root severance and reduction in available rooting volume. Root loss reduces anchorage stability and impairs water and nutrient uptake. Soil compaction associated with construction further limits oxygen diffusion and root respiration.”
“An encroachment of approximately 28% of the TPZ is generally considered unacceptable in Australian arboricultural practice. Impacts exceeding approximately 20–25% are typically regarded as high impact, particularly where excavation results in structural root severance. At this level of disturbance, recommendations often include tree removal due to unacceptable compromise of anchorage and long-term viability.
If a 28% encroachment had been presented in the original Arboricultural Impact Assessment at DA stage, it is highly probable that the recommended outcome would have been removal rather than retention. The recalculation reducing impact to 13% materially altered the planning assessment and facilitated tree retention.”
The Strata submitted that a report dating back to the time of the development application for 79A mentioned a tree root growing against or under the former retaining wall, demonstrating that the tree’s roots were present and were likely damaged by the works. Mr Harkness argued that it is open to the Court to find that excavations for the pool damaged roots and, therefore, to shift the cost of tree removal to Ms Armati and Mr De Coster.
In reply, Ms Armati and Mr De Coster submitted that no significant tree roots were observed during the excavation works. They submitted that all works were done according to the modified development application, which Council had properly assessed and approved.
I do not accept that consideration of the final development layout at 79 and 79A, including swimming pools, and the consequential 28% TPZ encroachment, would have resulted in the tree’s removal. Australian Standard 4970:2025 ‘Protection of trees on development sites’ defines notional root zone encroachment (TPZ was updated to NRZ, or notional root zone, in the 2025 update to the standard, changing only its name and acronym) greater than 20% as ‘major encroachment’. The standard states (within Clause 3.3.6) that in the case of major encroachment:
“The project arborist shall be engaged to explore alternative designs with the design team and/or demonstrate that the tree will remain viable…
For assessment of major encroachment a more detailed investigation is necessary. This can include research such as root investigation, soil analysis, historical records of the tree or site, relevant literature and examples of similar encroachments. [Reports] should be prepared to support the retention of the tree.”
Australian Standard 4970:2025 does not identify major NRZ encroachment as a trigger for tree removal, but recommends further investigation to assess impacts. Root investigation is a common approach. The location of the former retaining wall was likely to restrict the tree’s root growth so that significant root mass, and especially structural roots, were unlikely to be present south of the retaining wall where the ground was excavated for the swimming pool. Root investigation would likely have shown this. In his report, Mr Leonard’s discussion is theoretical rather than being based on any findings of impacts to tree roots at the site.
I conclude that works at 79A did not destabilise the tree or lead to its decline. But even if they had, the real risk of damage or injury arises from the structural defect at the base of the tree. Ms Armati and Mr De Coster have not contributed to this risk in any way, so the cost of mitigating the risk will remain with the tree’s owner, the Strata.
In the absence of any reasonable alternative to mitigate the risk, the tree must be removed. The Strata will arrange and pay for tree removal.
The willow myrtle is structurally poor and I am satisfied that it is likely to cause damage to the applicant’s property in the near future, or injury to a person. The tree’s removal is required to prevent damage or injury. Ms Armati and Mr De Coster have not contributed to this risk. The Strata will be responsible for tree removal and for planting a replacement tree. Ms Armati and Mr De Coster will need to provide access to their property for tree removal works. Given the tree’s form, it seems likely that branches will need to be lowered into their back yard. All branches and debris are then to be removed from their property via the Strata’s property.
The willow myrtle has damaged the dividing fence, which now requires remediation, the cost of which will be shared equally by the parties. Because the tree is to be removed, the fence will no longer need to allow for the tree’s future growth.
The Court cannot be satisfied that the tree has caused or contributed to any damage to Ms Armati’s and Mr De Coster’s retaining wall.
The Court orders that:
The application is granted to the extent of the following orders.
The respondent is to engage and pay for a suitably qualified (minimum AQF level 3) and insured arborist to remove the willow myrtle and to grind out its stump within 30 days of the date of these orders. These works must be done in accordance with the Safe Work Australia (2016) ‘Guide to managing risks of tree trimming and removal work’. All tree parts and debris, including branches above the applicants’ property once they are on the ground, are to be removed from the applicants’ property through the respondent’s property. The applicants’ property is to be left clean and tidy.
The respondent is to give the applicants 7 days notice of the works in Order (2).
On at least 7 days notice from the respondent, the applicants are to allow access to their property during reasonable hours of the day for the works in Order (2).
The applicants are to obtain three quotes from suitably experienced fencing contractors for remediation works to the dividing fence to restore it to a sufficient dividing fence of a similar style to the existing dividing fence, and are to provide copies of the three quotes to the respondent within 30 days of the date of these orders.
The applicants are to engage and pay for a fencing contractor agreed to by the parties, or the fencing contractor with the cheapest quote from Order (5) if they have been unable to agree on a contractor, to carry out the fence remediation works as quoted in Order (5). These fencing works are to be commenced after the tree is removed and completed within 90 days of the date of these orders.
The applicants are to give the respondent 7 days notice of the fencing works in Order (6).
The respondent and the applicants are to allow access to their properties during reasonable hours of the day for the fencing works in Order (6).
Within 7 days of receiving a copy of a receipted paid invoice for the fencing works in Order (6), the respondent is to pay the applicants 50% of the invoice amount.
Within 90 days of the date of these orders, the respondent is to plant in a suitable location on its property a tree that will reach at least 5 metres at maturity. The tree is to be planted at least half a metre from any structure and where space will allow for its development.
The exhibits are returned, other than Exhibit A.
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Correction made to "South-west" in [15]
Armati
The Owners �e" Strata Plan No 15695 [2026] NSWLEC 1136