Lister v Fraser & anor

Relevant background

1. According to evidence given orally during the on-site hearing and as presented in the application claim form (Exhibit A), the applicant purchased his property about 22 years ago. In late 2013 he observed cracks in the south-eastern corner of his garage in the proximity of the respondents' tree and brought the matter to the respondents' attention.
2. In September 2013 the respondents lodged a 'Request for Tree Works' with Ku-ring-gai Council seeking to remove the tree citing the damage to the applicant's garage.
3. On 23 October 2013, council's Tree Management Officer (TMO) wrote to the respondents and advised that their request for removal needed to be supported with additional information. The letter clearly details the information to be provided and includes the need for a physical investigation, by way of a trench adjacent to the structure, in order to establish the presence of roots and the need for a detailed report from a practising structural engineer.
4. On 20 January 2014 the applicant wrote to the council and advised council of the branch that fell and his concerns over the potential for injury and the damage to his garage. Another council TMO responded and suggested the applicant discuss his concerns with the tree owner; the applicant was also directed to the Trees Act and the Land and Environment Court's website. The officer also notes the council's earlier request for a report from a structural engineer.
5. On 2 July 2015, the applicant's lawyers wrote to the council and attached an Arboricultural Assessment Report from Mr Sam Allouche. Council was invited to consider the report and advise as to what action council was prepared to take to approve the removal of the tree. [The Allouche report was not included in the application claim form.]
6. On 22 July 2015, council's TMO, who had dealt with the 2013 application from the respondents, wrote to the applicant's solicitors informing them that one of council's arborists had inspected the tree in October 2013 and determined that the condition of the tree at that time did not warrant removal and that while the damage to the garage was observed it was noted that the garage was quite old and housed two cars and heavy machinery. The letter states that given the type of damage, further information was requested. The TMO also comments on the arborist's findings and whether the arborist was qualified to opine on the structural aspects of the garage.
7. Although there is no documentation to confirm this, on p12 of the Application Claim form, the applicant states that in 2016 the respondents lodged another tree removal application with council and that the applicant provided council with a structural engineer's report in support of that application [presumably the first report prepared by Mr Michael Ell - see below].
8. In March 2016 Ku-ring-gai council issued a 'Neighbourhood Notification' regarding proposed tree works. Further correspondence between the applicant and the council identifies that in May 2016 the respondents withdrew their application to remove the tree. Council advised that it was unable to assist the applicant and, as the matter is a civil dispute, the applicant could consider the powers of the Land and Environment Court under the Trees Act.
9. The applicant filed the Class 2 application with the court on 15 August 2017.

The damage and structural engineers' reports

1. The applicant describes the damage allegedly caused by the tree to his garage as: extensive cracking of walls, parting in the joints of the floor slab, and heaving of the floor. Photographs included in Exhibit A taken on 25 July 2016 and 3 July 2017 show the damage. Other photographs show the location of large tree roots at the base of the garage.
2. The freestanding double garage is located at the rear of the applicant's property. The rear wall is close to the common boundary between the parties' properties. The exact date of construction is unknown but 1943 aerial photographs of the site indicate that there were no structures on either lot at that time, however, a number of trees were present; whether the tree the subject of the application was present is difficult to determine. It is assumed that the dwelling and garage were constructed in the late 1940s/early 1950s. Therefore, the garage is assumed to be at least 60 years old.
3. In early February 2015, the applicant engaged Mr Michael Ell, a structural engineer, to inspect the damaged garage and prepare a report. A further report was prepared in September 2016 (both reports are included in Exhibits A and B). Exhibit C includes comments made in response to a report prepared by the respondents' engineer, Mr Garcia.
4. As stated in his 2015 report, Mr Ell undertook a visual inspection of the areas of the applicant's garage that were visible at the time of inspection. The garage is described in his report as a single brick construction with a concrete floor. The proximity of the respondents' tree is noted. A series of photographs illustrates the cracking in the walls. Mr Ell notes the parting of a joint in the floor slab. He states that the foundation material is clay however it was not possible to see the footings. Based on these observations, Mr Ell concludes: It is our opinion that the cracking that has occurred in the garage and shown in the photos attached, is due to the root system of the large gum tree at the rear of [respondents' property]. This tree will need to be removed to avoid further damage to the garage. The portion of the garage that has been affected by root damage is now not structurally adequate. This will need to be demolished and rebuilt. The footings will need to comply with the residential footings code and should be supported on plain concrete piers to a minimum depth of 1500.
5. The report includes Appendix B, which, apart from an extract from AS2870-1996 "Residential Slabs & Footings", comprises general material of unknown provenance about roots and structures.
6. The photographs in Mr Ell's report show a number of horizontal cracks in various parts of the garage; the main crack is a large diagonal crack in the rear wall from the corner of a floor vent (opposite the tree) towards the top of the southern corner. The crack is wider at the top.
7. In September 2016 Mr Ell reinspected the applicant's property and prepared another report. Photographs were taken and included in the report. In Mr Ell's opinion: in the garage walls closest to the tree, further cracks had opened and the existing cracks had widened; the door to the garage no longer closed; and the floor in the vicinity of the tree had heaved and the part in the slab had widened. Mr Ell concludes: "that the damage to the garage due to the gum tree has deteriorated further". He maintains his opinion that the damage is due to the respondents' tree and that it should be removed as a matter of urgency.
8. Neither of Mr Ell's reports identifies any roots nor explains the mechanism by which the tree has caused the damage.
9. Exhibit C is a further report from Mr Ell dated 9 November 2017, prepared following an inspection of a trench that had been excavated along part of the rear wall of the garage in the vicinity of the tree. The trench, which was still open at the time of the hearing, exposed the tops of three large diameter woody roots and part of the footing. Mr Ell estimates the footing to be approximately 150mm thick and extending approximately from the face of the brickwork. He estimates the width of the footing to be about 600mm. Mr Ell considers that the footing is common in buildings constructed in the 1930s and 1940s, well before the first residential footings code was published in 1986.
10. Mr Ell states: "One root can be seen directly under the cracking in the wall and footing". He also notes a number of fine roots, which he assumes to be from the tree, near the corner that has subsided. The report also includes comments on Mr Garcia's report and on the likelihood of poor drainage being the cause of the subsidence. Having observed the slope of the surrounding land, Mr Ell does not consider that water will pond in the vicinity of the footings and cause foundation movements. He opines that the small 'retaining wall' [a row of vertically placed pavers - referred to in Mr Garcia's report] would have any significant effect on the moisture content of the foundation clays by causing swelling and thus footing movement. Mr Ell considers that the tree was planted after the construction of the garage and that the nearby clump of bamboo will not have a significant effect on the footings of the building. In regards to Mr Garcia's comments on the guttering and storm water, Mr Ell considers that water will move away from the garage and that the guttering is twisted due to the movement of the wall. He agrees with Mr Garcia that the corner of the garage has settled but this has occurred due to the fine roots under the corner of the building taking water from the reactive clay thus causing the foundation material to shrink and the footing to settle.
11. In response to the filing of the Class 2 application, the respondents engaged Mr Hugo Garcia to inspect and report on the damage. He inspected the damage in October 2017. In his report (Exhibit 2) Mr Garcia describes the construction of the garage and the proximity of the tree to the rear wall and the southern corner of the garage. In his opinion, All of this suggest[s] that the crack on the rear wall has been caused by differential footing settlement at the corner of the building. The section of the side wall that is close to this corner is out of plumb and leaning to the outside. The rear wall is on vertical plumb."
12. Mr Garcia lists a number of observations and opinions including: the garage is constructed in a natural water course or channel; the soil around and below the garage would be wet or moist during rainy periods; the north-western side of the roof was covered by leaves and other debris and thus rainwater would overflow onto the ground next to the garage walls; the guttering on the south-eastern side was bent and twisted suggesting that rainwater would flow onto the ground next to the garage; the south-eastern side wall was out of plumb; a 'retaining wall' close to the southern corner would lead to ponding of water close to the garage; three roots were visible in the area in front of the tree but no tree roots were seen between the tree and the [southern] corner; the strip footing is 150mm thick and probably about 450mm wide and thus non-compliant with current standards; no piers in the corner of the garage; strip footings not pier and beam; horizontal crack along the sliding joint [between the wall above the footing and the concrete slab floor]; the diagonal crack is wider at the top than the bottom; and roof trusses mean there are no horizontal forces pushing the side wall of the garage from the top of the wall.
13. Based on these observations, Mr Garcia makes a number of comments and draws his conclusions. He considers that the garage has not been built to take account of the presence of nearby trees and that guttering and other structures should be maintained to effectively manage water away from footings. Mr Garcia concludes that the cracking of the garage is only due to differential footing settlement which has been caused by one or a combination of the following factors: Differential footing settlement caused by the presence of water in the vicinity of footings. Inadequate footing size for the type of soil under the footings and/ or site conditions surrounding the garage structure. Lack of maintenance of the garage structure and / or inadequate management of the rainwater [captured] by the garage and / or the soil around the garage. Possible leakage from any underground line carrying water that is situated in the vicinity of the garage.
14. Mr Garcia states: There is no evidence that root growth is the only cause of the cracking wall. There are no other cracks in the rear wall of the building or in the other corner of the rear wall. There [are] no tree roots in the vicinity of the cracked rear corner of the garage. It is my opinion that differential footing settlement is the cause of the cracking in the rear wall, not root growth.
15. Mr Garcia's report includes a number of attachments including photographs of the damage, diagrams of footings from AS2870-2011, and an extract assumed to be from a 1984 National Trust bulletin illustrating 'common crack patterns and their causes'. One of those diagrams appears to illustrate the type of damage observed in the garage.
16. Exhibit 3 includes Mr Garcia's response to Mr Ell's reports and further elaboration of his opinion regarding the applicant's stormwater; he also includes aerial photographs from 1943 and opines that the tree was present prior to the construction of the garage, contrary to Mr Ell's opinion that the tree was planted after the construction of the garage. Amongst other things, Mr Garcia notes the lack of any further investigations to determine the type of footing system under the garage in order to establish whether the tree roots are the only cause of the damage and or to exclude other possible causes of the differential settlement.

The tree and arborists' reports

1. As stated above, the tree the subject of the application is a mature Eucalyptus pilularis (Blackbutt) growing at the rear of the respondents' garden. There is no dispute that the tree is wholly or principally located on the respondents' property. The Blackbutt is one of several large trees in the respondents' backyard. There are a number of other large Eucalypts growing at the rear of other adjoining and nearby properties.
2. Both parties engaged a consulting arborist to provide expert opinion evidence.
3. The applicant engaged Mr Kyle Hill to inspect the tree. According to Mr Hill's statements included in the claim form, he inspected the tree on 19 November 2016 and again in February 2017. The purpose of the inspections appears to be to establish a possible link between the tree and the damage to the applicant's garage. Mr Hill states in his 'Tree Root Investigation' report dated 9 February 2017 that the tree has "reasonable health & vigour". It also appears that on the first inspection in November 2016 Mr Hill considered "…whilst it was obvious there was likely a link between the tree root system & the noted damage to the free-standing concrete & masonry garage advice was given that should the matter go before the court additional conclusive evidence would be essential to confirm the link. The suggested to be excavated (manually dig) trench along the rear outside now completed confirms the link between the discussed tree trunk structural roots & the severely damaged free-standing concrete & masonry garage.
4. Mr Hill's report includes photographs showing the crack in the wall and the location of roots in the trench. Mr Hill does not discuss how the root/s may have damaged the garage. Mr Hill notes the difficulty and limitations of installing a root barrier and suggests that the best solution is to remove and replace both the tree and the garage or possibly the repair of the garage.
5. The respondents' consulting arborist, Mr Michael Sullings, inspected the tree and the garage on 10 October 2017. In his report (Exhibit 1), Mr Sullings found the tree to be of fair to good health and vigour with some major dead wood and some crossing branches. He notes the tree to be about 1.45m from the wall of the garage with a large root in contact with the footing. He also notes the presence of a clump of bamboo about 1m from the south-eastern corner of the garage.
6. Mr Sullings states: Given the proximity of Tree 1 [Blackbutt] to the garage at [applicant's address], and the fact that structural roots were observed in contact with the footing of the garage, it appears likely that the damage can be attributed (at least in part) to the root system of Tree 1.
7. Mr Sullings does not discuss how the tree root may be affecting the garage.
8. Mr Sullings goes on to opine that it is likely that the garage was constructed after the tree was established and its construction did not take into account the woody roots, described as 'the zone of rapid taper'. He also considers the possibility that the structural damage could be attributed to the roots of the clump of bamboo which is close to the south-eastern corner of the garage, however he states that he saw no roots from the bamboo during his site visit. Whilst Mr Sullings assumes that the garage would have to be rebuilt, he suggests that appropriate construction methods, such as pier and beam or cantilevered/ suspended slabs, could be used to construct the new garage and for the tree to remain.

Oral evidence

1. The hearing commenced on site with an inspection of the tree from the respondents' property. The parties' engineers and arborists were present, gave oral evidence and were cross-examined. The trench along part of the rear of the garage wall was inspected. The tops of three woody roots were observed. One root appeared to be deflected along the footing towards the west, one large root (with a rock incorporated in it) appeared to grow down and was in partial contact with the footing, the remaining root was smaller and its direction was unclear. A number of fine roots were exposed within the topsoil. The edge of the concrete footing was also exposed but not to its full depth. The trench was of insufficient depth and length to determine the extent and location of roots at depth and any interactions with the footings, particularly around the south-eastern corner.
2. The damage, both inside and out was inspected. The evidence observed on site is consistent with the photographs included in the various reports and in the application claim form. The engineers clarified the construction of the garage: the concrete strip footings support a double brick wall upon which sits a concrete slab floor; above the floor the walls are single brick; the roof structure comprises trusses and the roof is clad in corrugated metal sheeting. In their opinion the floor is unlikely to be supported by additional piers. Between the lower wall and the floor slab is likely to be a metal strip. The brick walls are rendered. The garage is accessed principally through the double doors on the north-eastern side. A side door has been inserted into the south-eastern side wall close to the south-eastern corner. Further to the north along that wall is a window. Apart from one or more floor vents, there are no openings in the rear wall.
3. As stated above, part of the concrete footing was exposed. The engineers agreed that the footings are probably about 150-200mm deep and between 450-600mm wide. Whilst no soil testing has been carried out by anyone, the engineers agreed that the reactivity of the underlying clay foundation material is probably 'M', that is, moderately reactive [pursuant to s 38(2) of the Land and Environment Court Act 1979 - moderately reactive clays have a surface movement of between 20-40mm].
4. Mr Garcia placed a spirit level against the rear wall of the garage in the vicinity of the root and across the crack. It demonstrated that the wall had not been displaced in any direction including vertically; that is, the wall has not been lifted. Mr Garcia stated that if the roots were lifting the footing the wall would be displaced. The side/ south-eastern wall is clearly displaced. Mr Garcia maintained his opinion that water pooling in that corner, particularly from the displaced guttering, has caused the shrinking and swelling of the soil and ultimately its subsidence. Under cross-examination he considered that at most the Blackbutt had contributed to about 10% of the damage but the damage was not because of the root lifting the footing. Mr Garcia did not expand on how the root/s had contributed to the damage.
5. Mr Ell considers that the Blackbutt is responsible for 90% of the damage. Mr Ell agreed that the root/s did not appear to be lifting the wall and agreed that the south-eastern corner has settled and rotated, in his opinion the main reason being the extraction of water from the reactive foundation clay by the roots of the Blackbutt the subject of the application. In his opinion the bamboo will have had little effect. Under cross-examination, Mr Ell agreed that he had no actual evidence to substantiate his opinion but he maintained his position that the roots of the tree, being from a larger plant, would be more 'powerful' [at suction] than those of the bamboo which is smaller than the tree. When asked, if the underlying soils are reactive and there are likely to be roots throughout the soil, why the displacement of only that corner and no cracking elsewhere, Mr Ell considered that the insertion of the door in the corner is an inherent weakness and therefore, in his opinion, root suction will have the greatest effect in the weakest part of the structure. Mr Ell opined that the root, while not lifting the footing, will be acting as a pier and supporting that section of the wall, as evidenced by the crack starting at the root, and the unsupported section to the east has settled, principally because of root suction. He disagreed with Mr Garcia's proposition that the garage is constructed in a watercourse or that water is pooling in that corner, rather, Mr Ell indicated the slope of the land generally away from the garage.
6. In regards to root suction in that corner, Mr Hill stated that he thought it unlikely to be from the closest tree (the Blackbutt) as the finest roots which extract water from soil are generally furthest away. The roots in the vicinity of the corner could be from the bamboo or could be from other trees in the vicinity. Mr Sullings agreed that it would be very hard to quantify the specific effect of the roots of the Blackbutt on extracting water from that corner and agreed with Mr Hill that there are other trees in the area that would have their roots throughout the soil.
7. Both Mr Hill and Mr Sullings stated that they believe the largest root observed growing against the footing and close to the start of the crack is a cause of the damage but neither arborist was able to explain precisely where the root went or how it might be contributing to the damage. Mr Hill suggested that the root may have grown down then under and then up the other side of the footing. Mr Sullings opined that it looked like the large root has dived down but he couldn't say whether the root has turned. He also stated that while woody roots will expand as they grow, research [presumably in the literature] is that roots cannot exert enough pressure to lift a building. Mr Sullings also stated that he thought the root would have been there when the footing was poured.
8. As to the condition of the guttering, Mr Garcia maintained that water would leak from it down the wall and onto the soil near the south-eastern corner. Mr Ell maintained his opinion that the displacement of the guttering was due to the movement of the wall. The applicant tendered Exhibit D, a statement from a builder who stated that he replaced what he describes as a "50 year old" cement tile roof with corrugated roofing about 10 years ago and the guttering and downpipes were replaced at the same time. Mr Bolger objected to the tendering of the document on the basis that the estimated age of the building was unsubstantiated. The Exhibit was allowed but its relevance, if any, would go to weight.
9. Once inside the garage, the floor was inspected. Apart from some slight separation between and lifting of two sections of slab up near the south-eastern corner, and a fine hairline crack near the side door, the slab appeared in good order.
10. Mr Garcia observed that the 45º angled crack in the rear wall arises from the corner of the air vent in the lower portion of the back wall, that is, from another weak point in the structure.
11. The engineers were asked to consider how the garage wall could be repaired. Mr Garcia suggested that the eastern end of the rear wall and the southern end of the side wall could be removed back to the nearest double brick pier in each wall. The new walls and floor slab would then be supported by hand dug piers to current standards. While there was some disagreement from Mr Ell as to whether the floor slab would have to be removed and replaced, the engineers agreed that the tree would not have to be removed as the new piers could be positioned away from the roots and the elevated floor was not at any risk of being lifted by roots. The arborists agreed that the tree need not be removed but that care must be taken to avoid damaging any woody roots. The engineers agreed on and prepared a diagram showing the dimensions of any necessary piers as well as a scope of works should orders be made for the rectification of the garage [I have marked this Exhibit E).

Branch failure

1. One of the elements of the applicant's claim is that a large live branch fell from a tree onto his property damaging the roof of his dwelling and a gazebo. Photographs of the fallen branch are included in the application claim form.
2. During the hearing the arborists determined, and I concur, that the branch did not fall from the Blackbutt, the tree the subject of these proceedings, but fell from another Eucalypt on the adjoining property to the east of both parties' properties and is thus beyond the Court's jurisdiction to consider.
3. However, both arborists noted dead wood in the Blackbutt which they considered to be of a size that when it falls could potentially cause damage or injury. They agreed that the dead wood should be removed.

Submissions

1. Mr Livingston, counsel for the applicant, submits that the Court should be satisfied that the relevant tests in s 10(2)(a) are met. He relies on Mr Sullings' report in which Mr Sullings considers that the tree has contributed, at least in part, to the damage, a view supported by Mr Ell in his written and oral evidence and by Mr Hill. While he notes that there is agreement on the differential settlement of the corner of the garage, Mr Livingston also notes the difference in opinion as to causation, which in his submission goes to the roots of the tree.
2. Mr Livingston contends that Mr Garcia's evidence regarding the influence of water should be rejected on the basis of site observations. He asserts that the guttering has been displaced by the movement of the building, and is not, as suggested by Mr Garcia, a result of inadequate maintenance. Photographs taken in 2014 showing leaves on the garage roof can be given no weight as these were taken after the failure of the large branch. Mr Livingston maintains that Mr Garcia's evidence goes no higher than espousing other alternative explanations for which he hasn't provided any proof. However, Mr Livingston notes that Mr Garcia stated in oral evidence that the tree is about 10% responsible for the damage, as opposed to his written statements that don't apportion any contribution of the tree to the damage.
3. Mr Livingston submits that on the balance of probabilities, and consistent with the findings in Robson v Leischke at [179] the Blackbutt is a cause of the damage and thus the jurisdiction is engaged.
4. In regards to the matters for consideration under s 12 of the Trees Act, Mr Livingston contends: if the tree were to be removed it is unlikely to be noticed given the presence of other tall trees in the vicinity; from the 1943 photograph, the tree appeared to have been planted after the construction of the garage and was planted too close to it; the footings, and while not up to current standards were appropriate at the time. Mr Livingston submits that while the tree makes some contribution to amenity, this is a clear case where removal is appropriate and compensation for the repair of the garage is the full responsibility of the respondents.
5. In reply, Mr Bolger, counsel for the respondents, contends that the applicant has failed to prove that the tree has caused the damage and as such has not met the jurisdictional tests in s 10(2). He asserts that at best, the evidence amounts to speculation about the cause of the obvious structural damage. Mr Bolger notes the agreement of the engineers that the root, while touching the footing, has not lifted the rear wall. He submits that the onus is not on the respondents to disprove, but on the applicant to prove his case on the balance of probability.
6. Mr Bolger notes that contrary to Mr Ell's written opinion, his oral evidence is that the differential settlement is not a consequence of the large woody roots but of the fine roots removing moisture from the soil. He also notes the evidence on site that the immediate vicinity of the subsided corner is level and does not slope away. Mr Bolger contends that Mr Garcia's opinion is valid as it goes to the localised moisture conditions. While the root may be under the footing, as suggested by Mr Hill, given the limit of the excavation this remains unknown.
7. Mr Bolger cites Fang v Li & anor [2017] NSWLEC 1503 in which Galwey AC sets out a frame work for investigating and demonstrating claims of structural damage allegedly caused by trees. In referring to the steps listed in [59] of that judgment, Mr Bolger asserts that such investigations would ordinarily be expected to be undertaken by an engineer engaged by the applicant in order to demonstrate the cause of the structural damage, rather than the engineer simply recording the locations of cracking and the proximity of nearby trees. In this regard, Mr Bolger contends that both Mr Ell and Mr Hill have in essence assumed that the roots of the Blackbutt are the cause of the damage but their reports do not demonstrate the roots are the cause of the damage.
8. In regards to other evidence, Mr Bolger presses the proximity of the clump of bamboo to the damaged corner and asserts that there is no evidence of any localised removal of moisture by the Blackbutt. As to whether the tree was present before or after the construction of the garage, he submits that the 1943 photographs are unclear however both arborists consider the garage could have been built after the tree had established. Mr Bolger also highlights the absence of damage elsewhere in the garage.
9. However, if the Court finds that the tree is a cause of the damage, Mr Bolger contends that at best it remains a theoretical possibility. He notes the agreement of all experts that the tree need not be removed and that the applicant could take action to prevent further damage and given the crack was first noticed four years ago, the applicant could have investigated the cause at that sstage and then taken appropriate action.

Findings

1. With the benefit of the site inspection I was able to observe one large woody root from the Blackbutt in contact with part of the concrete footing of the garage. There is a relatively small crack in the footing at that point; apart from the crack, the footing in the vicinity of the tree, to the extent that can be determined by the limited depth of excavation, is otherwise level and in reasonable order. Despite the crack in the footing being relatively minor, I am cautiously satisfied that the root is likely to be a cause of that crack, which is sufficient to satisfy the relevant tests in s 10(2)(a) and thus engage the Court's jurisdiction under s 9 of the Trees Act to consider what, if any, orders should be made.
2. Apart from numerous cracks in many directions in the render on the brickwork, there is a large diagonal crack in the single brick wall arising from the corner of a floor vent in proximity to the base of the tree. Thus, on the face of it, it could appear as though the root has caused the damage to the garage. However, while the large woody root may have caused the crack in the adjoining part of the footing, the limited extent of the excavation is insufficient to prove the nexus between the root and the larger crack in the wall.
3. As stated above, Galwey AC in his judgment Fang v Li & anor [2017] NSWLEC 1503, sets out a Tree Dispute Principle to assist in demonstrating the cause of structural damage to buildings. Paragraphs [58] - [60] of that judgment are reproduced below. 58 At this point, it may assist future parties applying to the Court pursuant to Part 2 of the Trees Act, where such applications include claims of structural damage to property, to provide some framework for inquiry that might assist an engaged expert to carry out the relevant investigations that would assist the Court to consider and determine the matter. This list of investigations is not exhaustive, but would assist in forming a sound chain of reasoning to demonstrate causation, and to eliminate other factors. Each site is unique, and each situation may require its own combination of investigations. 59 In cases where it is alleged that tree roots are causing structural damage to a building or other property, consideration of the following matters, via appropriate investigations, may provide useful information. (1) If roots are found near footings, especially in areas where footings have moved, it is necessary to identify the tree to which the roots belong. This may be possible by physically tracing a root's path, or may require microscopic or DNA analysis. An arborist can provide useful information regarding species and growth traits of any nearby trees. (2) It is important to collect information on the building's history and construction methods, as well as the history of the surrounding area, including any trees removed in recent years. (3) The age, depth and construction type of the footings, especially in areas where footing movement is identified, is relevant and should be investigated and reported. (4) Identifying the part of the building or structure that has moved, and in which way it has moved, is critical to determining causation. This might be done by undertaking a survey of the building or structure to identify and be able to demonstrate where and how it has moved and the nature of the movement (whether lateral, rotational or vertical). This is important as some movements of a building or structure may not, in the circumstances, be possible to attribute to a tree. (5) Knowledge of where the building is still actively moving, during which seasons, and in which directions, will further assist in identifying causation. Where time constraints allow, this might be done by repeating the level survey over time, as well as monitoring any cracking patterns. (6) Where footing movement is identified, it is important to know the ground conditions and soil moisture conditions in the vicinity of movement, as well as in other areas for comparative purposes. This can be done by undertaking routine soil investigation, such as boreholes for soil classification and soil moisture testing. If these conditions vary over time as a consequence of seasonal or other climatic conditions, more extensive testing to ascertain the impact of such variable conditions may be required. (7) Downpipes and other pipes near the building, especially those near any areas of relatively higher soil moisture levels, can contribute to movement of footings. Therefore, the condition of all downpipes and other pipes should be investigated and reported. 60 To the extent to which the Court must be satisfied of causation, the burden of proof lies with the applicant. Such investigations would ordinarily be expected of an engineer engaged by an applicant to demonstrate the cause of structural damage. It would be unusual for an engineer to be able to demonstrate cause by simply recording the locations of cracking and noting the proximity of trees and locations of tree roots. Reports that include consideration of the above matters, with photographs and plans that clearly show their findings, would greatly assist the Court.
4. By and large I find the expert evidence is based on unfounded assumptions and speculation; assumptions that could have been substantiated by a more thorough investigation, requiring more extensive excavation, to establish the depth and directions of the woody roots, the actual dimensions and conditions of the footing, particularly in the south-eastern corner of the garage or whether there may be a void beneath the footing as illustrated in the most relevant of the diagrams included in Mr Garcia's first report. There has been no soil testing or simple investigations of soil moisture levels around the building. I agree with Galwey AC, the onus is on an applicant to prove their case.
5. I note that both arborists believe the root has contributed to the crack but neither of them have offered any evidence to substantiate that opinion. Mr Hill speculates as to where the root may go, Mr Sullings mentioned research on root pressure but provides no literature to support that statement. Mr Garcia's checking of the levels of the rear wall during the hearing led Mr Ell to agree with Mr Garcia that the root appeared not to have lifted the wall. There is no evidence to substantiate Mr Ell's alternative theory that the root is acting as a pier, or pivot point, and has thus contributed to the differential settlement of the south-eastern corner. Mr Ell's revised opinion is that the roots of the Blackbutt are almost entirely responsible for extracting moisture from that part of the soil. This is contradicted by Mr Hill who considers that fine roots from the Blackbutt are unlikely to be so close and thus extract water from that particular part of the soil; Mr Sullings notes the presence of many other trees and plants in the vicinity. If roots are extracting moisture from (assumed to be) reactive clay soils, then why only that location? Mr Garcia remains of the opinion that localised soil moisture, as a consequence of the failed guttering and the soil levels in the vicinity of the footing in the corner have led to its differential settlement; this may be entirely possible as the soil is slightly depressed in the area below the disrupted guttering, but there is no evidence of relative moisture levels from other areas around the garage. Both engineers agree that the presence of the side door is an inherent weakness in a building at least 60 years old.
6. Overall, given the insufficient evidence and the speculative nature of the expert opinions, I cannot be satisfied to the extent required by s 10(2)(a) that the tree has caused the large crack in the corner of the garage and as a consequence, this element of the application is dismissed.
7. In regards to the risk of injury, the applicant is concerned about the integrity of the building and the risk it may pose to people should it fail. It would seem that the risk arises from the possible collapse of part of the building and not directly due to some impact of the tree; however, if I am wrong in that finding, having determined that there is insufficient evidence to prove the nexus between the damaged corner and the tree, and thus to engage the Court's jurisdiction, no similar connection can be made in regards to s 10(2)(b).
8. However, as stated elsewhere, the arborists identified dead wood in the Blackbutt of a size that when it falls could cause damage to the applicant's property or potentially cause injury. This satisfies s 10(2) and orders will be made for the removal of dead wood from the tree.
9. Returning to the slight crack in the footing, while I have found it is probably caused in part by the tree root, the damage is minor and on the engineers' evidence the footing in that section remains level and apparently functional. I am not satisfied on the evidence that any remediation of the small crack is required. On the advice of the engineers, should further work be required on other parts of the garage, the tree need not be removed. The small crack in the footing does not warrant the removal of a large and healthy tree, which apart from providing amenity to the respondents and neighbouring properties, is likely, as a locally indigenous species, to contribute to the local ecosystem and to biodiversity.

Orders

1. As a consequence of these findings, the Orders of the Court are: 1. The application to remove the Eucalyptus pilularis (Blackbutt) is dismissed. 2. The application for compensation is dismissed. 3. Within 60 days of the date of these orders the respondents are to engage and pay for an arborist with a minimum qualification in Arboriculture of AQF level 3 to remove all dead wood > 30mm in diameter at its base from the Blackbutt closest to the applicant's garage. 4. The work in Order (3) is to be carried out in accordance with AS4373:2007 Pruning of Amenity Trees and with the WorkCover NSW Code of Conduct for the Amenity Tree Industry or equivalent safety standard. 5. Should it be required, the applicant is to provide all reasonable access on reasonable notice for the purpose of quoting and for the safe and efficient carrying out of the work in Order (3). 6. All exhibits except A are returned.

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Judy Fakes Acting 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: 08 December 2017