A Tree Manager’s Perspective by Jake Tibbetts

This is a very important and welcome decision regarding alleged subsidence claims involving trees. This case re-emphasises how the law should be applied, and sets a positive precedent for lower courts (who decide the majority of these claims). It also goes someway towards rebalancing the law’s view on trees and reasonableness between 'neighbours'. As the manager of Islington’s Tree Service, I thought it important to give my perspective on the outcome of this case.

I believe that this case could result in reducing significantly the numbers of subsidence claims and the value of those claims against councils who manage trees in a reasonable manner. Tree owners can now argue that they are not liable for damage that has occurred prior to them being made aware that damage has occurred, solely on the basis of a potential risk. In this case, it was only when the potential risk became a real risk that the liability for damage passed to the tree owners.

This judgement recognises the importance of urban trees and the social benefit that they bring. More importantly it clarifies what foreseeablity actually means. This decision moves the perception away from the position that a tree on clay soil near a building equals a “reasonably foreseeable” risk, as has previously been presumed.

In this case all of the damage (some £200,000) occurred prior to Islington Council being informed that there was damage or that the trees were implicated in that damage. Once Islington Council were presented with evidence, we felled two street trees and also allowed for a tree with a Tree Preservation Order (TPO) on the neighbouring property to be removed. Mature plane trees grow on clay soil in this part of the borough, but we do not have a local history of subsidence cases. The claimants argued that it was reasonably foreseeable that the damage would occur (because there were trees on clay soil near buildings) and therefore we should be found liable for all of the costs.

The trial court found that neither Islington Council nor Family Mosaic (who owned the neighbouring property) could reasonably be expected to foresee that their trees might pose 'a real risk' of causing damage to the property until they had been notified that the property had suffered damage, and reasonable evidence had been provided. Until that point we had satisfied our duty to eliminate or minimise potential nuisance and could therefore not be held liable for prior damage, as we had acted reasonably.

This case does not change the situation for damage that occurs after tree related subsidence has been identified as the cause, or in other words when a potential risk has become a real risk.

How we manage trees was also looked into. The argument that 'pruning does not work' damaged the claimants case as the judge was faced with an interesting dilemma – if pruning does not work, what can a reasonable owner do to manage their trees? This argument promotes the notion that the only way to remove the risk of subsidence is to fell all trees near a property on clay soil! This is a disproportionate and unreasonable response which would result in the “desertification” of the urban environment.

What do tree managers need to do in light of this case? I believe it remains critical that we assess our trees, our claims history, our soils, and from that knowledge identify areas which we consider present “real risk”.

Tree managers must identify areas where they have a number of claims, or “hotspots”, and adopt appropriate management regimes, based around this understanding.

Crucially, the judgment does not go as far as to say that tree owners can simply wait until damage occurs and then maintain implicated trees.

This approach would fail to take account of the real risk that a tree might pose. However, where you have determined that there is low risk, in some areas, it may be appropriate not to prune at all.

The other area that this judgment reinforces for me is that reasonableness between neighbours is a key factor.

At all stages of the claims process, and through the management regimes we set up, tree managers need to be able to demonstrate that they have been reasonable in their approach. If we can do this, as previously mentioned, we should be able to see the number of claims and the amount we pay out for subsidence cases reduce drastically.

Seeing the wood for the trees - Article by Clyde & Co

The Court of Appeal confirms that when assessing whether there is a ‘real risk’ of tree related subsidence damage, one must consider whether the relevant trees present a risk, the nature and extent of which imposed upon the owner a duty to take preventative or remedial action over and above any regime of tree management already in place.

The Court of Appeal on Friday 13 July 2012 handed down its judgment in the matter of Berent v Family Mosaic Housing and London Borough of Islington [2012] EWCA Civ 961, and dismissed the Claimant’s appeal.

The claim was advanced on the misapprehension that mere proximity of trees to a building equated to a reasonably foreseeable risk of damage. Both the trial judge and now the Court of Appeal found that there was no ‘real risk’ of reasonably foreseeable damage from the adjoining trees.

The Trial Judge, His Honour Judge Wilcox sitting at the Technology and Construction Court, dismissed the claim finding that prior to damage occurring to the Claimant’s property, neither Defendant could have appreciated that there was a ‘real risk’ that their trees would cause damage. The Claimant’s interpretation of the test of ‘reasonable foreseeability’ in that where a building is within influencing distance of a tree there was a risk of damage, lead the trial judge to say obiter that:

“[Islington] mindful of its obligation under Town and Country Planning Acts and the preservation of such amenities as a treed environment could not reasonably contemplate the desertification of such a neighbourhood by wholesale tree felling to avoid the risk of damage. Such an approach it seems commended by the Claimant almost gives rise to strict liability” [emphasis added].

The obstacles to the Claimant succeeding on her appeal, required her to show either (i) that the trial judge was wrong to find that Islington had in place a prudent regime of pruning or (ii) that Islington should have had a cyclical pruning policy thereby showing an alternative to wholesale removal or the ‘desertification’ the trial judge referred to. Had she overcome those hurdles, she would still have needed to persuade the Court of Appeal that the judge’s findings on causation were incorrect.

The Claimant had pleaded that the Defendants had failed to ‘pollard, crown or otherwise manage or control the growth’ of the implicated trees. However, the evidence of her arboricultural expert, Mr Kelly (the co-author of a paper entitled “Tree related subsidence: Pruning is not the Answer”), as found by Lord Justice Tomlimson, “did not support the Claimant’s pleaded case insofar as that alleged a failure properly to manage trees by pruning prior” [to the damage occurring]. The expert arboricultural evidence had not identified the implicated trees as posing a greater risk than others, or that they should have been subjected to a regime other than the one adopted, or indeed that pruning would have eliminated or minimised the risk in any event.

The Court of Appeal reiterated that a balance needed to be struck when assessing the reasonably foreseeable ‘real risk’ of damage and the inter- related enquiry of what it is reasonable to do in light of that risk. Ultimately, it may be reasonable to take no steps to eliminate an unlikely risk.

The Court of Appeal again highlighted that a further factor to be balanced in this process is the ‘social utility’ of the act which leads to the risk. Had the Claimant been correct, and that trees which were merely proximate rather than ‘a real risk’ needed to be felled, this would be to ignore the social and amenity value of trees.

What can be taken from this decision?
In this matter the Claimant’s property is situated on a road in which there are 276 trees and approximately 300 properties. The properties are of

a similar age and similar distance from the trees and given the age of the properties, it was likely that the properties had shallow foundations. The difficulty for Islington was to assess which of the properties was likely to be damaged and whether there was ‘a real risk’ of damage being causes to a particular property by a particular tree.

The decision is of considerable importance to local authorities and housing associations managing their tree stocks. It confirms that simple proximity of a tree to a building does not elevate the risk of damage from being a potential to ‘a real risk’ of damage. An assessment needs to be made as to whether there is a ‘real risk’. Factors that should be considered include whether there have been previous claims in the vicinity and any other factor that might mean that a tree poses ‘a real risk’. The importance of frequent and severe pruning of trees identified as ‘a real risk’, prior to damage occurring, is again highlighted. However, where the reasonably foreseeable risk of damage is small, it is reasonable to match a pruning regime to the risk, and in some possible scenarios, not to maintain at all. The social benefit of ‘a treed’ environment was highlighted, in that it would not be reasonable to fell all trees that pose a risk (but not ‘a real risk’) to eliminate or minimise that risk.

Tree owners are advised to assess their stock and focus works on the trees assessed as posing ‘a real risk’

Kal Sandhu of Clyde & Co acted on behalf of Islington in both the trial and the appeal. He was instructed by Zurich Municipal, who supported Islington’s stance that the risk of damage was not reasonably foreseeable.

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