An inquest into the death of a young New Zealander killed by a falling branch at Kew Gardens in London has heard that a phenomenon called summer branch drop may be the cause.
The family of Erena Wilson, who died last September 23, aged 31, from injuries caused by a falling branch from a Lebanese cedar tree at Kew are calling for warning notices to be put in place and areas cordoned off if there is a chance of branches falling from trees that potentially have the problem.
The phenomenon occurs in mature broadleaf trees when a sudden downpour follows a long dry period and water being sucked through the tree causes the brittle branches to explode. It generally happens in afternoons in late summer.
Family solicitor John McLindon QC told the inquest at West London Coroner's Court: "Is this incident itself just a fluke that there was not more than one fatality or that other people did not suffer very serious injury?"
A report by tree expert Jeremy Barrell for the family that brought up summer branch failure and other issues with Kew's tree management including pruning regimes was rejected as evidence by assistant coroner Elizabeth Pygott.
She commissioned an independent tree report but said Kew arboretum head Tony Kirkham's report could be given as evidence when the inquest restarts, at a date to be set.
But Pygott said: "It is appropriate to look at issues of pruning and whether it was or wasn't pruned and would that have made any difference to the outcome."
McLindon said: "This is virtually a public place controlled by a public body that has visitor numbers exceeding 1m a year. If the cause of death on this case is caused by the phenomenon summer branch drop then, in a bad analogy, that brings about an avalanche, an accumulation of natural causes that bring about, at the time, possible danger to people in the vicinity.
"If this is the case and evidence produced by the parents through Barrell's report and other literature and should be accepted by the court this must trigger wider concern by the coroner that circumstances creating a risk of death will occur or are continuing to exist in the future."
McLindon linked the death to that of Sophie Howard, 13, who died after a tree branch hit her in a Peterborough park in 2011. The coroner found summer branch fall to be the cause.
McLindon said: "There are very serious questions of ongoing concern about safety in these type of conditions at Kew and what if anything needs to be done. That must be a part of your remit to the independent expert."
He added that warnings for the public and cordoning off areas had been in use 30 years ago but "these two steps seem to have fallen away for reasons the parents don't know".
Account manager Wilson, from Auckland, died when a branch fell in 30mph winds while she was walking with two friends.
Her uncle Pieter van Vliet, 49, said he had hoped the inquest would have been completed in a day but "Mr Mclindon is asking a set of valid questions. We're not experts but Kew gardens has a lot of trees so there is potentially a good reason for bringing this up. We'd never heard of summer branch drop before until very, very recently. A large element of this is to make sure it does not happen again and is understood.
Expat family and friends planted four magnolia trees at Kew in April next to a bench with a silver fern plaque in her memory.
Uncle Henry van Vliet said: "We miss her so much. But this has brought us together as a family."