The risk of trees injuring the public is an emotive subject, and the question of balancing that risk with the implications of inspection regimes remains a difficult one to answer.
There is no doubt that tree safety is headline-grabbing news - the issue was brought into focus earlier this year when 23-year-old Emily Diamond was killed when she was struck by a falling branch after an accident in which a bus had hit a tree, near London's Tower Bridge.
But a co-ordinated approach is being taken by the arboriculture industry, led by the National Tree Safety Group (NTSG), in response to guidelines from the British Standards Institute.
A draft British Standard on tree safety inspection was published in May - BS 8516 - but the recommendations, which include tree inspection frequencies of between one and five years as well as recommendations on tree work, have prompted a strong reaction from an industry concerned about the fundamental need for such guidelines.
Following unprecedented interest in the document, the British Standards Institute extended the deadline for consultation on the new recommendations to the end of August.
BS technical committee B/213 Trees chairman Mick Boddy says responses will be fully examined in the coming months, and the project reconsidered in the new year: "We received an extensive number of responses and we are in dialogue with the NTSG, as well."
But with the consultation period closed, industry leaders believe it will be impossible for the British Standard to get off the ground without support.
Arboricultural Association director Nick Eden says the widely held view at the moment is that the draft British Standard is not even worth thinking about until further research on tree risk had been done. "We have taken the stance that we are not even interested in the content of the standard because the timing is wrong. It may be that a British Standard is not necessary at all, but we don't know that yet."
Tim Moya Associates arboricultural consultant Tracy Clarke says: "The general feeling is that it needs to be more co-ordinated with the NTSG.
"It would be good to have an integrated approach, but whether that should be in a British Standard is questionable. There is a lot of experience in the industry and people are concerned about tree safety, but it has to be proportionate."
An inquest in June recorded a verdict of accidental death after an 11-year-old boy was killed by a falling tree while on a school trip at the National Trust's Felbrigg Hall in Norfolk - the tree involved had been inspected just a few months before the tragic event.
The debate was also examined this week at the Arboricultural Association's conference at the University of Kent in Canterbury, on 14-17 September.
Boddy was scheduled to speak on British Standards and arboriculture during the event, while US-registered consulting arborist Dr Nelda Matheny was also in the line-up.
Matheny's talk on the state of risk assessment in the US, how it has evolved and the UK's struggle to define a standard of care sought to bring further attention to the British Standard question.
Arboricultural Association technical officer Guy Watson explains: "The standard has started to feel quite prescriptive about when we should inspect trees.
"But we need to deal with the more fundamental issue of which trees need inspecting before we move into the detailed requirements of when and how we do it.
"The Health & Safety Executive says the risk is six deaths a year, which is one in 10 million."
The NTSG, which includes representatives from the Arboricultural Association, London Tree Officers' Association, Confor, English Heritage and the Forestry Commission, is now researching the need for a British Standard.
Hundreds of people involved with the sector came together at the end of May for a conference entitled Tree Management for Public Safety, which aimed to work towards formulating a unified industry position.
Since the conference, the NTSG has tasked Middlesex University's professor of risk management, David Ball, with assessing tree risk and the cost implications of BS 8516.
Professor Ball is analysing the risks posed by trees compared with the risks of man-made items, such as steps, and expects to circulate an interim report in the new year.
Eden adds: "This whole debate is about the risks and liabilities associated with owning trees, and how much resource should be expended on assessing tree safety compared with the level of risk to society as a whole."
NTSG group chairman Sir Harry Studholme explains that a cross-industry approach to developing policy is paramount and that one of its key aims is to develop guidance that will clarify how landowners can satisfy their duty-of-care obligations to the public.
"Those responsible for trees need clear, overarching, national guidance on how to reasonably meet their obligations in a manner that is proportionate to the risks and does not jeopardise the benefits enjoyed by society from trees," he says.
"The NTSG has written to the BSI to express the group's view that the draft BSI standard is not an appropriate approach at this time.
"Nonetheless, NTSG has asked BSI to be involved, as part of the industry consensus, taking the issue forward."
Arboriculture & Forestry Advisory Group (AFAG) board member John Price, who is countryside manager at Milton Keynes Council, said the idea of a British Standard was not a problem, but he was concerned about the implications on the ground.
"Will it drive people too far one way to just get rid of trees? That is a big debating point," said Price. "It is always a balancing act, but over-regulation can cause problems."
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