Is your expert really ‘the expert’? And why it matters

[ THE MATTER OF EXPERTS and their counsel has been in the headlines recently – including during the Brexit debate, as some questioned the calibre of opinions offered. My own profession, arboriculture, is largely unregulated, so when considering the ‘expert’ opinions of others, I need to consider the calibre of the expertise. When a party uses expert opinion that is limited there can be consequences, such as increased costs of resolving claims, as cases take longer to conclude.

Some time ago I was asked to assist in a case where a tree failure had caused a personal injury. The owner’s agent defended the situation: they had employed a specialist, the failure was not foreseeable and the tree had failed in a storm. When I looked more closely, the ‘specialist’ was a local contractor with no specialist skills, there hadn’t been a survey and there was no storm. Meanwhile, the costs of settling had increased.

Experts often cite their credentials, including degrees. That can seem impressive, and I recall reading the report of one expert on a case I was involved in. Their credentials were similar to mine, with a degree and professional memberships. However, as I dug a little deeper I realised that their degree was unrelated to the subject; and away from that their credentials were less substantial. In that case the claimant had been assured of the merits of their claim, which incurred costs and proved unsuccessful.

While the evidence of the expert witness is valued, sometimes others with expertise in a field, but perhaps lacking formal accreditation, can be as valuable. In another case, where a beech tree suffered root plate decay and blew over in a storm, the matter of foreseeability was raised. A boundary wall was damaged in the process and a loss adjustor, qualified as a chartered surveyor, was sent to visit the site.

The loss adjustor, familiar with the difficulties of using decay detecting equipment to assess root decay, but not trained in arboriculture, concluded that the failure was not foreseeable. A little knowledge, however, can be dangerous. An acquaintance of the claimant, an experienced ecologist with an understanding of decay strategies in trees and able to identify different fungi, observed a fungus on the tree which causes root plate decay.

A detailed decay assessment wasn’t needed: the presence of the fungus made failure foreseeable. For the owner of the tree, or their insurers, the claim process had become avoidably protracted and costs had increased.

As an expert, it is important that I keep to my specialist area. I can comment on matters outside of that, such as weather, and I can also offer opinion on aspects that are common sense. For example, I may be asked to comment on whether a tree has caused a wall to collapse. I don’t need to be a structural surveyor to observe the pile of bricks left! With every job I ask myself why I am instructed, to ensure that the issues are within my specialist area. It is important that experts truly have expertise in their area. If I am asked to review a case, it is one of the first elements I consider.

Sometimes, the absence of expertise is actually the issue. Following the storms of February 2022 I was asked to assess whether the failure of one tree, which had demolished a property, was foreseeable. Fungi were on the remains and had been present for several years, indicating the inevitable. However, the insurance company had not requested a tree report before issuing cover and the position of the fungi was not obvious to the lay person. q