Mrs Josephine Robbins v London Borough of Bexley

Hearing dates: 8 & 9 February 2012

Introduction

This is a claim for damage to a suburban house by the roots from a nearby poplar tree, which is one of a line of Hybrid Black Poplars growing in a park owned by the Defendant ("the Council"). The nearest poplar was about 30 m away from the rear of the house.

The Claimant is the owner and occupier of 6 Radnor Avenue, Welling, Kent. It is one of a row of semi-detached houses on the east side of Radnor Avenue which back onto Danson Park. The poplars were planted along the boundary of Danson Park, in a line running parallel with the ends of the rear gardens of the houses in Radnor Avenue, that lies roughly north-south. Internal documents disclosed by the Defendant ("the Council") suggest that the trees were planted at some time between about 1935 and 1945: being poplars, they are therefore mature trees.

The house was built in about 1935 and the Claimant acquired it in 1969. It appears that in the early 1970s a two storey extension was added to the rear of the house, to which a further single storey extension was added a little later.

In September 2003 the Claimant first noticed damage to the property. She saw a crack in the wall of the downstairs single-storey back room and then, a week or so later, another crack in the wall of the rear bedroom on the first floor. She notified her insurers and shortly thereafter surveyors came to inspect the property: trial pits were dug and bore holes were drilled in the garden to investigate the soil conditions.

During the summer of 2005 the cracking became worse but further significant damage did not occur until the summer of 2006, when some of the original cracks became about 25 mm wide. Between May 2005 and May 2008 a programme of crack and level monitoring was undertaken.

During 2006 two other events occurred that have assumed considerable significance in this case. First, in April 2006 the Claimant removed a magnolia shrub (or tree), known as T4, that was about 2 m away from the left hand corner (viewed from the road) of the single-storey rear extension. Second, in September 2006 some of the poplars, including the nearest, known as T2, were very severely pruned.

During the following summer, 2007, the movement of the rear extension was very much reduced. It is the Claimant's case that this was the result of the severe pruning of the poplar T2.

All the experts, both engineering and arboricultural, are agreed that the cracking and movement to the rear of the Claimant's property was the result of seasonal volume changes in the subsoil caused by the extraction of moisture by vegetation. The principal issue in the case is: which vegetation?

The losses sustained by the Claimant, principally the cost of repairing the damage and underpinning, are claimed in the sum of £147,081.48. Subject to liability, the amount of these damages is now agreed. In addition, the Claimant seeks £3,000 by way of general damages for distress and inconvenience. I understand that this figure is also accepted on the same basis.

The Council denies that T2, or any of the poplars, caused the damage. Alternatively, if it did, it asserts that it was only under a duty to act reasonably in the light of a reasonably foreseeable risk. It submits that an unusual feature of this case is that only one poplar root has been positively identified in the garden of No 6 and, even more extraordinarily, no poplar roots were found under the foundations when the remedial work was carried out. It says that in the circumstances of this particular case it was not obliged to do anything.

The procedural history

This claim was brought in the County Court. It came on for trial on 4 October 2011 in the Croydon County Court. The judge heard three days of evidence and the case was then adjourned to 21 November 2011. On that occasion the judge directed the arboricultural experts to renew their meetings in order to attempt to agree the extent to which the poplar T2 had been pruned in September 2006. By the end of that day the experts finalised a further joint statement. This ran to over 40 pages.

On the following day, 22 November 2011, the hearing resumed, both sides expecting to call the arboricultural experts. However, the judge decided to terminate the hearing and to transfer the case to the Technology and Construction Court on the ground that the latest joint statement by the experts was unsatisfactory and that the case was, or had become, far from straightforward. The judge was right: the case is not straightforward, and this has certainly not been assisted by the best efforts of the two arboricultural experts. But whether or not that justified abandoning the hearing in mid-trial and transferring the case to another court is a different matter.

Be that as it may, Akenhead J, as Judge in Charge of the Technology and Construction Court, directed, very properly if I may say so, that the trial should be resumed and concluded before a judge of the Technology and Construction Court at the earliest possible opportunity. It was in these circumstances that the trial was resumed before me on 6 February 2012. It was agreed that the parties should obtain a transcript of the evidence given by the expert engineers so that I could have the benefit of reading this, even though I had not heard the evidence. Since I have reached the conclusion that little turns on any differences between the evidence of the two expert engineers, this is not a course that has disadvantaged either party.

At this point I must turn to the nature of the vegetation in the vicinity of the property and the history of the site investigations.

The surrounding vegetation

Attached to this judgment, marked Appendix B (there is no Appendix A), is a plan produced by Dr Frank Hope, the arboricultural expert retained by the Council, which was appended to the first joint statement by the experts as being agreed. In fact, as is now accepted, it contains two errors: T4 is shown on the wrong side of the garden of No 6, and T5 is in the garden of No 12 Radnor Avenue (not No 10, as shown).

In 2005 a vegetation survey was carried out by OCA, Consulting Arboriculturalists. They recommended the removal of magnolia T4 and poplar T2: they considered the latter to be the most likely main cause of the damage. They noted that pruning was generally damaging to tree health, longevity and amenity given the 70%-90% reduction required annually to make any difference to soil moisture content. 1

In the table below details of each tree are given. Tree heights are based on estimates carried out by OCA. The distances are from the NE (rear left) corner of the extension:

Distances in the column marked OCA were taken or estimated during the survey in 2005, but the distance to T2 is now agreed at 30.7 m (to centre of trunk). Distances in the column marked Hope were taken or estimated by the Council's expert, Dr Hope. Distances marked with * have been adjusted by me in those cases where Dr Hope appears to have measured the distance from the tree to the

SE (rear right) corner of the extension (this is not always clear because in various places Dr Hope has referred to the south-western, south-eastern and north-western corners of the extension: I have assumed that the first two are the same corner). In reaching my conclusions I have taken into account the comments made by the parties on a previous draft of this table.

# The distance from the building to oak T5 has been assessed by the Claimant's expert, Ms MacQueen, (from a 1:500 OS plan) as 27 m, not 22 or 24 m.

In the final column I have shown the height multiplied by 1.25. Where this is greater than the lowest estimated distance from the extension, it appears in bold. This is because there appears to be a rule of thumb that the zone of influence of high water demanding trees (such as poplars) is between 1.2 and 1.4 times the tree's mature height 2. It has to be the mature height because the rule has been developed for the purpose of providing guidance on the depth of foundations required in the vicinity of a tree. It therefore has to cater for the worst case of root influence, which is assumed to be when the tree is mature. However, it is not clear to what extent this rule can be relied on in the case of a tree that has not reached its full height. I shall consider this...