The Owners Corporation Strata Plan 47318 v The Owners Corporation Strata Plan 44716

Relevant background 11The parties each engaged an arborist and an engineer to prepare a report; for the applicant - Mr Don Katauskas, geotechnical engineer, and Ms Susan Hobley, arborist; for the respondent - Mr Don MacLeod, engineer, and Mr William Home, arborist. All of the experts are familiar with the tree and the site and were present at the hearing. Mr Andrew Simpson, Tree Management Team Leader, Woollahra Council, was also present at the hearing. 12Both the tree and the retaining wall have been the subjects of a number of actions by the parties. According to Mr Simpson's statement [Exhibit AA], Woollahra Council records show: in 1997 a Notice of Proposed Order was issued in regards to the retaining wall; in 1998 approval was given under the Tree Preservation Order for pruning to improve outlook; in 2008 an application under the TPO for tree removal on the basis of whole tree failure was refused; in February 2009 a review of the TPO determination also refused removal; in December 2009 a Development Application was lodged to replace the wall and remove the tree (see [14]). 13In material contained in Exhibit 3, a bundle of documents from a Woollahra Council meeting on 21 March 2011, the original retaining wall around the Norfolk Island Pine may have been constructed in 1972. According to Mr MacLeod's report (Exhibit 1), the condition of the retaining wall adjoining the tree was the subject of another engineer's report (Bray Consulting) in 1996. According to that report, the rendered brick retaining wall was cracked and bowed. There were a number of subsequent inspections and reports by Bray Consulting, staff from Woollahra Council and others. In 2004, steel straps were installed to strengthen the brick retaining wall. 14In 2009, the respondent lodged a Development Application (DA) with Woollahra Council for the demolition of the existing retaining wall and construction of a new retaining wall. A number of (late) submissions sought the issuing of an emergency order from council for the removal of the tree. One of these submissions came from the applicant, based on a report prepared by Mr Katauskas, and another from one of the residents within the respondent's property. Apparently the main concerns were in regards to the stability of the tree, however, the Katauskas report of 2009 notes a horizontal crack in a wall [presumably the wall in question] above a [now removed] swimming pool on the applicant's property. 15Council deferred its determination of the development application pending further assessment from an independent external arborist [Tree Wise Men]. The Tree Wise Men reviewed a number of other arboricultural reports, as well as engineers' reports. The arborist also inspected the cracking of the applicant's wall and noted the repairs to a vertical crack near the gate. The independent arborist's report to council concluded that the wall was not providing support for the tree; pressure from root growth had most likely contributed to the failure of a structurally inadequate wall; there was no significant likelihood of whole tree failure; there was adequate soil volume to support the tree; there was no conclusive proof that the cracking of the [applicant's] wall was a direct result of the tree's roots; the tree was a prominent, significant specimen in good health that should be retained; and the retaining wall should be rebuilt in a structurally adequate way without the cutting of any roots in excess of 50mm in diameter. 16The DA was approved and the retaining wall subsequently rebuilt in 2011. The new wall comprises horizontal treated pine sleepers/'walers' held in place by galvanised steel 'soldiers'/posts, the bases of which are founded on the sandstone bedrock and grouted at their base. The soldiers are anchored into the bedrock with threaded high tensile steel bars placed through the top and bottom of each soldier. 17According to Mr Home, who was present during the installation, and confirmed by Mr Simpson, as specified in the conditions of consent, clearance was provided between the inside of the new retaining wall and the root ball to accommodate future growth.

The damage 18The applicant's case is based on a report prepared for them by Mr Don Katauskas, a Consulting Geotechnical Engineer, and dated 27 January 2014. 19The wall is part single, part double brick that forms the eastern boundary of the applicant's property. The fence comprises panels between brick columns. The inner side of the wall is faced with sandstone tiles. The Norfolk Island Pine is growing behind an engineered retaining wall to the east. Between the respondent's retaining wall and the applicant's wall is a concrete path. The original soil level at the base of the tree is about 1m above the path; due to fill associated with the construction of a pool on the respondent's property, the new soil level is about 1.5m above the path. The pathway is on the respondent's property however it provides a right of way for pedestrian access to a number of nearby properties. There are a number of services beneath the path including sewerage, drainage and communications. 20According to Mr Katauskas, the southern end of the most southern panel of the wall has rotated by approximately 5 degrees. There is a displacement and separation of about 30mm between the top of the panel and the adjoining column. There are a number of cracks in the mortar between the two lowest courses of sandstone tiles on the inside of the wall. In addition to the damaged wall, there is movement and cracking in the stairs that lead from a gate in the wall onto the applicant's property. The gate sticks and has been adjusted on several occasions. The damaged structures are within about 2m of the tree. 21Mr Katauskas is of the strongly held opinion that roots from the Norfolk Island Pine have caused the damage and he states: Because of the dynamic and increasing pressures exerted by the continuously growing tree, in my opinion there can be no effective permanent solution to restricting pressures on any structures within the zone of influence of the tree and its roots. The damage to the walls and walkway are continuing, and addressing this will ultimately require drastic and expensive remedial measures. The only long-term solution to this situation is to remove the tree. 22Mr Katauskas also raises concerns about the long-term adequacy of the new retaining wall as he states that the soldier piles are displaced from vertical and the timber infill is rigid and immovable. In his view, this indicates that the new retaining wall is under some stress. 23Both Mr MacLeod and Mr Katauskas have visited the site on several occasions and have prepared reports on the integrity of the original retaining wall. Mr Katauskas has inspected the site on a number of occasions, the first being 3 March 2009, then 22 February 2011, 6 December 2013 and then 10 January 2014. As part of his earlier investigations, Mr Katauskas made several bore holes into the pathway and near the tree to determine the nature of, and depth to, the underlying bedrock. 24Similarly Mr MacLeod inspected the site on 18 August 2008 and 13 January 2009. In January 2010 he reviewed a number of reports in response to the DA. On 27 February 2014, Mr MacLeod reinspected the retaining wall for the purpose of this hearing. He also reviewed Mr Katauskas' 27 January 2014 report. 25In response to Mr Katauskas' latest report, Mr Macleod states that Mr Katauskas has provided no evidence, for example by way of test pits in the pathway, to support his opinion that roots are impinging on the wall's footings, thus creating the rotation. In Mr MacLeod's opinion, the wall is constructed in un-reinforced brick masonry and is acting as a retaining wall, something it is not designed to be. In his view, normal soil pressures could cause such rotations without any roots. In regards to the new retaining wall, Mr MacLeod considers the slight displacement to be within normal tolerances and given the natures of construction, the slight displacement has no bearing on structural adequacy. In his opinion there is no need to remove the tree. 26Mr MacLeod's report also includes calculations on static loading of the tree in regards to its likely failure. As this element of the application is no longer pressed, expert evidence relating to this aspect is not considered in this judgment. 27In response to Mr MacLeod's opinion regarding soil pressure as a likely cause of rotation, Mr Katauskas [in Exhibit B] states that the applicant's wall is founded on sandstone bedrock at the foot of a sandstone ledge; the wall incorporates other garden beds and is effectively buttressed by the steps; and there is inadequate soil volume behind the wall to cause pressure. He reiterates his opinion that the damage can only be attributed to root expansion causing uplift and horizontal pressures against the wall. 28During the hearing, the location and extent of the damage was inspected and Mr Katauskas' summary of it confirmed. The pathway between the relevant walls was noted to be in relatively fair to poor condition. There were many patches of different materials, some much older than others. There was a drain inlet close to the rotated pillar. Some minor cracking of the path was noted between the corner of the retaining wall and the pillar/gate, but no lifting of any significance. 29The engineers' oral evidence supported their written opinions. Mr MacLeod stated that if roots were present he would expect to see an uplift of the paving. Mr Katauskas said that there is always a reason for a crack in a structure and in this case it is because of a root/s from the tree. 30When asked, the engineers agreed that the damage to date could be considered 'severe' in accordance with the relevant standard; that is, the crack is wide enough to be in that category. However, the damage is essentially cosmetic and not structurally significant. However, Mr Katauskas pressed his assertion that unless the tree is removed, the damage will worsen. The engineers also agreed that some additional movement of structures near gates was possible and that the loading on the wall created by the sandstone tiles could have an effect; in Mr Katauskas' view the effect would be negligible, Mr MacLeod considered the effect would be minor. 31Ms Hobley indicated a woody root at the base of the retaining wall, and based on photographs she had seen of the exposed roots when the old wall was removed, opined that this root was a likely cause of the damage given its direction of growth. Mr Home stated that the root had been dead for some time. This was confirmed on site. 32On the basis of Mr Katauskas' and Ms Hobley's assumptions that roots were the cause of the damage to the wall and stairs, the experts were asked to consider what, if any, alternatives to tree removal there might be. 33Mr MacLeod suggested that if roots were confirmed, a root barrier could be installed close to the applicant's wall in order to prevent future damage. The wall could then be repaired by retrofitting ties between the pillar/pier and the brick panel. 34The arborists agreed that a root barrier would be feasible but varied slightly in their opinion as to where it should be located. It was also agreed that any proposed root barrier would necessitate an exploratory trench to identify the size and location of any roots that may be present and then determine whether cutting the roots would have any unreasonable impact on tree health or stability.

The tree 35The Council's position, as represented by Mr Simpson, is that the tree is a structurally sound, healthy specimen of good form that is visually prominent and should be retained. Mr Simpson agreed that while there may be roots below the path that are affecting the wall, there is no evidence to prove their presence. He also stated that given the number of services in the path, any installation/ maintenance of them would normally involve the tradesperson severing any roots found. 36Ms Hobley states that the tree is a mature specimen that appears healthy and thriving. She said that it was not possible to investigate the base of the tree because of soil level changes however she saw no serious structural problems in the canopy, stem or branches and that the crown density was consistent with the age and species of the tree. In her opinion, lifting and cracking of the concrete in the path is consistent with root development and in her view, the damage to the pillar is likely to have been caused by a root from the tree. 37Ms Hobley disagrees with Mr Simpson as to the visual significance of the tree; indeed a considerable portion of the report deals with the tree's values. While the issue of whole tree failure was not pressed, Ms Hobley, both in her report and in oral evidence, noted the exposure of the tree to strong winds, the possibility of increased storm events with climate change, and future interactions with its environment that may compromise its stability. 38In her view, the public value of the tree is minor and could be eventually replaced by a more suitable replacement tree. 39In his report, Mr Home stated that in his opinion, the tree's health has improved since his last inspection. In order to determine why the top layer of sleepers was warped, he removed them and found no signs of root activity and opines that this may be normal because of moisture changes in the timber. He saw no obvious changes in the integrity or condition of the retaining wall. In his opinion the tree should not be removed.

Submissions 40Mr Rundle, for the respondent, contends that there is no dispute between the arborists, including those involved in earlier activities, that the tree is a healthy, thriving tree with no obvious defects. The majority of arborists who have inspected the tree agree that the tree is stable. In short, the tree is worthy of retention. He takes issue with Ms Hobley's appraisal of its significance given it can be seen from Elizabeth Bay as well as from elsewhere in Darling Point. 41Mr Rundle submits that the applicant has failed to take reasonable steps to reach agreement, a jurisdictional requirement imposed by s 10(1). For example, if a root barrier was a genuine issue, then there should have been some intention or notification given to his client. Although he cites Preston CJ in Robson v Leischke [2008] NSWLEC 152; (2008) LGERA 280 at [191]-[196] and the "less demanding" language of the requirement to reach an agreement, he considers that given the long history of issues around the tree, the applicant's effort has failed to meet the requisite standard. 42In regards to the jurisdictional test in s 10(2)(a), he refers to Smith & Hannaford v Zhang & Zhou [2011] NSWLEC 29. At [62] Craig J states in part "something more than a theoretical possibility is required in order to engage the power under [the Trees] Act...". Mr Rundle contends that there is no evidence supporting Mr Katauskas' hypothesis that roots are exerting pressure on the applicant's wall and that Mr MacLeod has put forward feasible alternative causes including the construction of the wall and soil pressure. Mr Rundle cites Dixon CJ in Holloway v McFeeters [1956] HCA 25, (1956) 94 CLR 470 at [10] in regards to competing hypotheses and that inferences may be drawn only where one hypothesis is more probable than another. In this respect he considers the applicant's case to be speculation and should be dismissed on the basis of absence of jurisdiction under s 10. 43Mr Clay, for the applicant, submits that the Court must balance the evidence of the damage caused by the tree against the value of retaining the tree. While he accepts that the tree makes a contribution to the landscape, he maintains that given the size of the tree and its continued expansion, further damage is inevitable unless some remedial action is taken. He argues that the "nettle should be grasped" sooner rather than later so that a more suitable replacement species can be planted that will provide benefits but avoid the problems associated with such a large tree as the Norfolk Island Pine. Deferring the action would only increase the expense of removal and rectification of damage. 44Mr Clay asserts that the test for the level of satisfaction of s 10(2)(a) is not high. Given the type of damage in the immediate proximity of the tree, he contends there is more than a theoretical possibility of the tree being at least a cause of the damage. 45With respect to Mr Rundle's contentions regarding s 10(1), Mr Clay maintains that there is evidence of correspondence between the parties and the wording of the Act does not require an attempt to be made on all issues and possibilities.

Findings 46I am satisfied that the applicant has made a reasonable attempt to reach an agreement, particularly given the long history of the tree and the retaining wall and the participation of the same experts over much of that time. In Robson at [194], Preston CJ states: 194 The Trees (Disputes Between Neighbours) Act 2006 does not specify any particular time at which the applicant must make a reasonable effort to reach agreement with the tree landowner, other than fixing the end point by requiring that the Court cannot make an order under the Act unless it is satisfied that the applicant has made a reasonable effort to reach agreement with the tree landowner. Hence, although it would be preferable for an applicant to make a reasonable effort to reach agreement with the tree landowner before making application to the Court, so as to avoid Court action, there is no requirement to do so and a reasonable effort to reach agreement can be made after making the application at any time up until the Court determines the application [emphasis added]. 47The next question is whether s 10(2)(a) is satisfied to the requisite standard. As discussed in Robson at [176] - [189], there must be a nexus between the tree, the subject of the application, and the damage to the applicant's property. At [179] Preston CJ notes that it is sufficient for the tree to be "a" cause. 48When asked, it was confirmed that no expert had undertaken any excavation to prove the presence of roots in the vicinity of the rotated wall and pillar. Although Direction 13 in the standard 'Directions of the Court' in Tree Dispute matters provides for access for inspections, other than visual inspections, no other investigations took place. 49It is agreed that the damage wall and gate are close to the tree however, as considered in many such cases, proximity does not necessarily mean causation. 50I note in Holloway, Dixon CJ in part at [10] states: In the present case the true cause of the accident is in truth unknown. The state of facts reached by inferences is itself compatible with a number of hypotheses, some of them implying fault on one side, some on the other, some on both sides. Hypotheses of this kind are not inferences....The inference may be made only as the most probable deduction from the established facts [emphasis added], but it must at least be a deduction which may reasonably be drawn from them.... 51In the present case before me, the actual cause of the damage to the wall is unknown. Mr Katauskas' hypothesis is that roots have caused the problem, Mr MacLeod says no evidence of root pressure has been produced and there are other potential causes - the footings of the wall and soil pressure, which in my view is a similar hypothesis. While both hypotheses are possible, none are proven. 52In matters such as these, it is relatively simple, although somewhat disruptive, to prove the presence or absence of roots, and therefore to establish the facts, by excavating beside the damaged structure. There have been many cases where this has been undertaken and appropriate orders made. 53In the matter before me, the nexus between the tree and the damaged wall remains a 'hypothetical possibility'. I am not sufficiently satisfied on the evidence before me that roots from the Norfolk Island Pine have caused the damage to the applicant's wall. While there is minor cracking in the concrete, there is no obvious lifting of the path near the wall and the only root that was seen is dead. There are other possible and unknown influences of the below ground infrastructure in the immediate vicinity of the pillar and gate. Therefore as s 10(2)(a) is not met, the Court has no jurisdiction to make any orders under Part 2 of the Act. 54However, if I am wrong in this, even if the roots are a contributing factor, I would not, as a matter of discretion, order the removal of the tree. The damage, i.e. the cracking, while classified as 'severe' does not constitute structural unsoundness. I agree with the council and the respondent's position that the tree is a healthy specimen that makes an important contribution to public amenity. 55Given the matters discussed at the hearing, the parties are also aware of an alternative process for mitigating any potential future impacts. 56As discussed in Hinde v Anderson & anor [2009] NSWLEC 1148, a fresh application can be made if the circumstances have changed since the Court determined an earlier application and there is fresh evidence. The judgments in McCallum v Riodan & anor [2011] NSWLEC 1009 and Zangari v Miller (No 2) [2010] NSWLEC 1093 give some indication as to what the Court considers to be 'changed circumstances' and fresh evidence.

Orders 57The Orders of the Court are: (1)The application to remove the Norfolk Island Pine is dismissed. (2)All exhibits except Exhibit A are returned.

Judy Fakes Commissioner of the Court DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated. Decision last updated: 02 May 2014