Kam v Hamilton

The tree and its location 7The tree is a mature Blackbutt. It is growing on the eastern side of the respondent's back garden at the end of a tennis court and close to the boundary between the parties' properties. The tree has a diameter at breast height of approximately 1.5 m. It is approximately 4 m from the corner of the applicant's dwelling.

Relevant background 8Ms Kam has owned her property since 2003. Over the past 5-6 years, Ms Kam contends that she has had cracks in the external wall and the pillar repaired on many occasions. Shortly after Ms Hamilton purchased her property in 2008, and again in 2009, Ms Kam raised the issue of cracking in the corner of her house adjacent to the Blackbutt. Ms Kam requested the removal of the tree. 9In 2011 Ms Kam carried out renovations that included replacing the first storey walls and a window in the wall adjacent to the boundary between the properties. 10In February 2011, Ms Hamilton engaged an arborist, Mr Bruce Macleod of Arborcraft, to undertake a visual inspection of the tree and Ms Kam's wall. The report notes that the tree appeared to be in good health with a good structure. 11Under Mr Macleod's instructions, trenches were hand dug along the wall on both the applicant's and the respondent's property. The report dated 10 May 2011 shows a large woody root measuring about 450 mm in diameter growing adjacent to and along the boundary wall footings on the respondent's side of the wall. 12The report notes that the trench established the footing of the boundary wall to be structurally connected to another wall that forms part of the applicant's courtyard, which in turn is connected to the footings of the house, including the supporting column. 13The report recommends removal of the tree on the basis that: the root is too large to cut without compromising the structural stability of the tree; rebuilding the footings and bridging the root would be an onerous obligation on the applicant; and the ongoing growth of the root would lead to further damage. 14In July/August 2011, Ms Hamilton wrote to Ku-ring-gai Council, presumably applying for permission to remove the tree on the basis of the damage to Ms Kam's property and the Arborcraft report. It seems that a joint application was made. From the incomplete set of correspondence in the respondent's bundle of evidence, it would appear that the council requested a 'Test of Significance' as the tree was deemed to be part of a threatened ecological community. In addition, the council requested further root mapping and reports from a structural engineer and licensed builder. A letter dated 7 October 2011 to council from the respondent and her husband questions the council's grounds for the additional ecological reporting. 15At approximately 11am on 13 December 2011, a large branch failed from the tree onto the respondent's tennis court. The respondent wrote to council on 14 December requesting consent for the immediate removal of the tree. There is no evidence of council's response. 16Ms Hamilton engaged Keith Crews, Professor of Structural Engineering, University of Technology, to inspect the fallen branch. He inspected the branch on 17 December. In his report dated 21 December 2011, he opines that the failure: ...occurred as a consequence of damage induced by wind loading and the self weight of the branch, combined with ineffective (discontinuous) fibre structure in the outer layers (sapwood) beneath the cambium layer and bark of the branch, particularly where it joined the main trunk of the tree... 17Professor Crews' report indicates other forks of the tree in which he says there are localised pockets of degradation.

The hearing 18The hearing was conducted on site. Before commencing the hearing I disclosed to the parties that I had worked for many years with Mr Macleod however I was unaware that he had written the report on the tree and we had certainly not discussed it. The parties did not ask that I recuse myself from the matter and, in the circumstances, I did not think it necessary to do so. 19The fallen branch was inspected and Professor Crews indicated the discontinuous structure of the wood fibres in the part of the branch at which the failure occurred. Some discussion of branch structure followed. 20It was noted that the failure occurred at approximately 500mm out from the junction with the trunk. Oral evidence from the respondent suggests that the failure occurred on a calm day. 21Using binoculars, I inspected the upper parts of the canopy - particularly the branch unions identified in Professor Crews' report. I noted darker coloured bark but no obvious defects. The branch attachments appeared normal and sound. 22Professor Crews was questioned as to the predictability of future failures, particularly when based on ground level assessment. He said that it would not be possible to predict such failures without more detailed aerial inspections and testing. 23The trench on the Hamilton was inspected and the size and location of the large woody root noted. A crack in the brick wall above the footing adjoining the root was noted. 24On the Kam property, the recently rendered wall around the courtyard was inspected. Mr Nigel Lane, a handyman employed by the Kams for the past five years, indicated areas of the wall and column that he had patched and repaired on a regular basis. 25As Professor Crews is a structural engineer, various engineering solutions were discussed including the installation of expansion joints and other means of avoiding future damage. On the basis of the exposed root, the observed continuous footing and the nature of the cracks, Professor Crews concurred with the parties that the damage to the Kam dwelling is most likely due to pressure exerted by the root onto the contiguous footing. Absolute proof would require more extensive and expensive investigations.

Jurisdiction 26Under s 10(2) of the Act, the Court must not make an order unless it is satisfied that the tree concerned has caused, is causing, or is likely in the near future to cause, damage to the applicant's property or is likely to cause injury to any person. 27The parties have agreed to consent orders however the Court must satisfy itself that it has the jurisdiction and that the consent orders are appropriate. 28The level to which the Court must be satisfied is discussed by Craig J in Smith & Hannaford v Zhang & Zhou [2011] NSWLEC 29. Section 10 mandates that the Court must be satisfied of the causal nexus between the tree the subject of an application and the damage claimed by an applicant. This requires an assessment of all the evidence before the Court. This evidence may be factors other than the tree and which may require the input of a range of expert witnesses. At [62] Craig J states in part that something more than a theoretical possibility is required in order to engage the power under [the Trees Act]. The nexus must be established on the "preponderance of probability".

Findings 29With the benefit of the site view and hearing from the parties and Professor Crews, I am satisfied to the requisite level, that the large woody root growing against the wall footings, is a cause of the damage to Ms Kam's property. There is no doubt that the root is a major structural root arising from the tree on the Hamilton property. I am also satisfied that the continued growth of the root will continue to cause damage to the applicant's property. 30With the expertise I bring to the matter, I agree with the findings in the Arborcraft report that severing the root is likely to compromise the stability of the tree. I note that the root is on the tension side of the tree and therefore of considerable importance to its stability. 31With respect to possible engineering solutions, I accept Professor Crews' qualifications in this area. It would seem to me to be an onerous and expensive undertaking to rebuild the affected portion of the Kam property to allow for future root expansion but maintain the structural integrity of the dwelling. 32With respect to the risk of future branch failures, I find Professor Crews' written opinion about further failures to be inconclusive although I am satisfied with his examination of the failed branch. His report identifies several branch junctions in which he says there is degradation that may lead to similar failure of wood fibres. However, on site he acknowledged that the branch failure did not occur at the junction and that predicting future failures would be difficult. 33The type of failure is commonly known as 'sudden limb failure' or 'summer branch drop'. The specific cause is unknown but the failures are unpredictable. One failure does not necessarily mean another will occur. 34However, as I am satisfied that the tree can be removed on the basis of the damage caused by the roots, any risk of future limb drop is negated.

Orders 35As a consequence of the forgoing, I make the following orders agreed by consent. (1)The application to remove the Blackbutt at the rear of 45 Fiddens Wharf Road Killara is upheld. (2)The application to remove the Blackbutt at the rear of 43 Fiddens Wharf Road at Killara is dismissed. (3)Within 30 days of the date of these orders, the respondent is to engage and pay for an AQF level 3 arborist to remove the tree to a depth of at least 200mm below ground. The root adjacent to the footings of the boundary wall is to be severed from the trunk. (4)The work is to be carried out in accordance with the WorkCover NSW Code of Practice for the Amenity Tree Industry.

J 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: 24 January 2012