By arboricultural consultant and accredited expert witness Mark Chester of Cedarwood Tree Care.

The role of the expert witness in advising on claims is a key element. Having an informed guide to give counsel on the merits of a case can ensure that wise decisions are taken either to pursue or defend a claim. What may surprise is that arboriculture, my own specialism, is unregulated. During my two decades as an Arboricultural Consultant, I have encountered evidence, sometimes quite limited being given undue merit, as those instructing are unaware of the limitations of the ‘expert’.

When I am instructed to review a case, a starting point is to explore existing evidence and its merit. I have found the term ‘expert’ being applied widely to individuals whose credentials are not thus. In one case, where a tree had broken and cased a road accident, the tree owner strongly defended their situation, and the condition of the tree, based on the opinion of their ‘tree expert’, who suggested inclement weather was the reason for the failure. It was when I explored further and found out the inclement weather was not in that locality, and the ‘expert’ was the individual who mowed the lawns and trimmed the trees, that the claim was recognised as having merit.

In another case, the claimant’s expert cited their degree as their most senior credential. It was, but the subject was not related to the tree-related claim, and thus not relevant. Earlier this year, I was asked to comment on the merits of a claim to replace a damaged conifer hedge. The insurance company was concerned about the value of the claim, which seemed high. When I explored, I was advised that part of the cost was due to the expense of importing the replacement conifers, Leyland Cypress, from the EU. This is often the case for plants not grown in the UK. However, the Leyland Cypress was first propagated on an estate in Powys, Wales, owned by the Leyland family. It is widely grown in the UK and does not carry a premium from being imported.

For one claim, the claimant cited the advice of their landscape specialist after trees had been excessively pruned during work for power line clearance. The proposed works included digging out stumps of damaged trees, planting substantial replacements and regrading the site. As I appraised the representations made by the claimant, it was soon evident that their specialist was a digger driver used to site clearance work and the methodology for reinstating the site was disproportionate to the damage.

In 2021, a case involving a neighbour dispute over a fruit tree resulted in one party having a bill for £250,000 in legal costs and compensation. I was asked at the time about this case, and how it could have happened (I appeared on the Jeremy Vine Show to share some thoughts). A reflection is that it is important to provide informed, impartial counsel to the party instructing, or to both parties. As an accredited expert witness, my duty is to the courts, and to provide the instructing party with clear advice. I often need to spend time with an instruction identifying what the key issues are, amongst what I call ‘the noise’. There is usually a degree of emotion involved; it is important to put this to one side, to remain calm.

I remember one expert witness, who has operated within arboriculture, sharing at a seminar that they had tried to persuade the jury on a case of the merits of their client’s claim. Whilst I understand this view, I recognise that this is the role of the client’s legal team. There are few feelings to compare with a judge dismissing the merits of one’s opinion when summing up. I have to remember that, whatever the outcome, my role is to ensure that the decision-makers are informed of my own observations. Whether they agree with my conclusions is not my responsibility.

There can also be a tendency by the expert to provide extensive commentary and pages of text detailing a case. When I was being trained by the Bond Solon team for the Cardiff University Expert Witness accreditation, which I gained in 2012, Nick Deal, one of the trainers, shared that, when writing the report, remember that the judge has to read it. A succinct account is often appreciated. Summing up at the conclusion of a recent hearing, the barrister for the party instructing me, observed to his client, ‘In Mr. Chester, you have a credible expert, and an excellent report. Mr. Chester has done a good job’. Regardless of the outcome, that for me is a job well done.

A loss adjustor commented, ‘exactly what I need’.

And I was able to reassure one client, seeking to resolve a neighbour dispute concerning a tree, that the CPR Part 35 expert witness report would be independent and impartial, and could be relied on by both parties. My role is to assess the evidence, without fear or favour.

My own credentials? A degree in Amenity Horticulture, Chartered Arboriculturist, Fellow of the Arboricultural Association and Cardiff University Expert Witness.
And a reflection from one instructing party, for whom I was, initially, simply the tree man, on seeing my report, ‘You know your stuff, don’t you?’

For further information visit treeconsultants.org.uk