Ash dieback: Killer tree disease set to cost UK £15bn

The issue of biosecurity is set to become increasingly important to prevent alien invasive pathogens entering the UK habitat

The outbreak of ash dieback disease is set to cost the UK in the region of £15bn, it has been estimated.

Scientists expressed shock at the "staggering" financial burden on taxpayers.

The authors warn that the cost of tackling the fallout from ash dieback far exceeds the income from importing nursery trees.

It was an imported nursery tree that initially brought the deadly disease to these shores.

They added that it was the first time the total cost of the outbreak had been estimated.

"We estimate that the total may be £15bn," explained lead author Dr Louise Hill, a researcher at Plant Sciences at the University of Oxford.

"That's a third more than the reported cost of the foot-and-mouth disease outbreak in 2001.

"The consequences of tree disease for people really haven't been fully appreciated before now."

Young and susceptible ash trees quickly succumb to the pathogen

The disease, also known as chalara dieback of ash, was first reported in the UK in a nursery in 2012, and was recorded in the wider environment for the first time in 2013.

Since then it has spread to most parts of the UK.

The Forestry Commission says it has the "potential to cause significant damage to the UK's ash population, with implications for woodland biodiversity and ecology, and for the hardwood industries".

In Europe, the pathogen has caused widespread damage and has killed and infected millions of ash trees.

'Huge impact'

As well as estimating the loss from losing an economically important species, the £15bn figure takes in account the loss of "ecosystem services", such as water purification and carbon sequestration.

Report co-author Dr Nick Atkinson, senior adviser at the Woodland Trust, said: "What we were drawing attention to is that there is this huge financial and economic impact of a tree disease epidemic."

The authors, writing in the Current Biology journal, estimated that the total cost of ash dieback would be 50 times greater than the annual value of trade in live plants to and from Britain.

"What you have to look at is, essentially, the risk we are taking by trading across borders against the benefits, which is the financial gains coming from that market," he told BBC News.

"The £15bn cost that we are now facing is the direct outcome of a trade that was worth a few million pounds."

The researchers said that the majority of the cost will be shouldered by local authorities.

"As we know, local authorities are not well funded and they are certainly not funded enough to deal with an epidemic of this magnitude," observed Dr Atkinson.

"There is this hole in the policy of responding to events like this."

And it is something that is very likely to happen again in the near future, they warn, as there are 47 other known tree pests and diseases that could arrive in Britain and cause more than a billion pounds (or more) worth of damage.