The hearing and findings on causation
18The stumps of the trees were inspected. Tree 2, was a small diameter tree of a size not requiring permission under council's Tree Preservation Order. No issues of current damage were pressed about this tree however, concerns were raised about future damage that may have occurred. From the evidence of the small size of the stump, it is highly unlikely that any orders would have been made for any interference with this tree as the Court has consistently upheld the guidance decision in Yang v Scerri [2007] NSWLEC 592, as a rule of thumb, the 'near future' is deemed to be a period of 12 months from the date of the determination.
19The damage alleged to have been caused by Tree 1, the larger of the two trees is: the displacement and cracking of a section of low brick wall between the properties (on top of which is a panel of timber lattice); the displacement of sections of a concrete path on the applicant's side immediately adjacent to the wall; the cracking and displacement of a brick retaining wall some distance below the tree; and the cracking and fretting of bricks on the top of the retaining wall that forms the top of several steps.
20The size of the stump as well as the evidence of the applicant and a nearby neighbour Mr Taylor, suggest that the tree was a mature specimen. Growth rings were evident and would suggest that annual incremental growth in more recent years has been no more than 10mm or so.
21Dr Barda was on site to provide assistance to the Court. The photographs he took in (presumably) late September 2011 were used to assess any subsequent movement that may have occurred in each of the elements in contention. The basis of Dr Barda's report is that the damage to the boundary wall, retaining wall and path is due to root growth and that the resulting damage to the path is a dangerous trip hazard. When questioned as to whether he carried out any excavations to confirm the presence of roots he said he did not as it would have been too difficult.
22With respect to the low brick boundary wall, Dr Barda contends the bowing and cracking has been caused by the tree. Whilst no roots were exposed, I am prepared to accept, on the bare preponderance of probability, that the tree has caused the displacement, and to that end, s 10(2) is satisfied for that element of the application. The question of how much damage has occurred in the eight-month period is unclear however, there do appear to be more cracks than shown in the photographs. Given the extent of the bowing of the wall, I am very surprised that it was only noticed by the applicant in March 2011 as it would appear to something that would occur gradually and not suddenly.
23The section of lattice on top of the wall did not appear to be damaged. There may be a slight displacement of one of the posts but Dr Barda's report made no mention of it and nothing was pressed at the hearing.
24In regards to the footpath, it is the second slab to the north of the retaining wall that is most in contention. It would appear that the bowing of the boundary wall has caused the minor sideways displacement of this section of concrete path. However, the slab appears to have subsided significantly on its eastern edge. This has resulted in exposed edges on the eastern sides of the adjoining sections of path, which to some extent, could be considered to be trip hazards. The subsidence on the south-eastern corner of the slab seems to have increased by 10-20mm since the photographs were taken. Again I am surprised that this was not noticed earlier than March 2011.
25The respondent contests the cause of the subsidence. Apart from no roots being observed, it was pointed out that the path is on a slope and is laid on the soil beneath which is sand. Apart from recent heavy rainfall, the applicant regularly hoses the area and workers relocating a gas service have also hosed the area. The suggestion being that the underlying sandy soil has been washed away from the edge of the slab leading to the subsidence. The applicant contends that during the time they have resided there, there has been a lot of rain and regular cleaning.
26On the evidence before me, I am not satisfied to the level required by the Act that the tree has caused anything other than the slight sideways displacement of the slab. It would appear from the gap beneath the slab that sand has been washed away. I am not satisfied that the increase in the level of subsidence and the resulting trip hazard since the respondent took ownership of her property, that the tree is the cause.
27With respect to the brick retaining wall, Dr Barda contends that the cracking is due to extra loading placed upon it by the roots of the tree. He considers there can be no other explanation. He says that the absence of weep holes in the wall is not an issue.
28Given the distance of the stump from the retaining wall and the absence of any proof of root growth behind the wall, I cannot be satisfied that the cracking of the wall is due to the tree and not some other cause including soil and water movement, adequacy of the structure and any damage that may have been occasioned to it by other activities. It is unsubstantiated speculation that the wall has been damaged by the tree and therefore s 10(2) is not satisfied with respect to this element of the application.
29Similarly, I am not satisfied that the fretting and cracking of several bricks on the top of the retaining wall that form the top of three brick steps is in any proven way caused by the roots of Tree 1. It would seem to be that a reasonable explanation could be that wear and tear associated with the normal use of the stairs over time has caused the degradation of the bricks. I note similar cracking of at least two bricks at the eastern end of the wall.
30Therefore in summary, I am prepared to accept that the tree has caused damage to the low brick boundary wall and the slight sideways displacement of one section of concrete path. Therefore s 10(2) is satisfied for these elements of the application, and the Court may consider what orders, if necessary should be made. I am not satisfied to the level required by the Act of the causal nexus between the tree and the subsidence of the path, the cracking and slight displacement of the brick retaining wall, the condition of the bricks along the top of the wall that form a step, and any alleged damage to the section of timber lattice fence. Therefore, the orders sought for compensation of these elements of the application are dismissed.