A deadly fungus that is predicted to kill off virtually all of the country’s ash trees will leave the UK with a bill for around £15 billion, a new study has revealed.
Scientists at the University of Oxford came up with the figure after assessing the predicted impact of ash dieback disease, which originated in Asia and is lethal to Europe’s native ash trees.
First seen in Britain in 2012, the infection will cost a third more than the foot-and-mouth outbreak in 2001.
Much of the price tag will be in lost benefits to society provided by trees, such as water and air purification and locking up carbon, but the cost of felling sick specimens is also in the bill.
Nearly half of this – £7 billion – will need to be stumped up in the next ten years.
Experts are warning this outlay is just the tip of the iceberg, since many of the UK’s tree species are under threat from a raft of pests and diseases arriving here as a result of the warming climate and imports from other countries.
Study leader Dr Louise Hill, plant sciences researcher at the University of Oxford, said: “The numbers of invasive tree pests and diseases are increasing rapidly, and this is mostly driven by human activities such as trade in live plants and climate change.
“Nobody has estimated the total cost of a tree disease before and we were quite shocked at the magnitude of the cost to society.” She says the full implications of tree diseases had not previously been quantified.
The researchers believe the total bill could be reduced by replanting lost ash trees with other native species, but curing or halting ash dieback infection is not possible.
They are now calling on governments to focus on preventing introductions of other non-native diseases to protect our remaining tree species.
“It is clear that to avoid further economic and ecological impacts, we need to invest more in plant biosecurity measures,” said co-researcher Dr Nick Atkinson, senior conservation advisor for the Woodland Trust.
“We need to learn from past mistakes and make sure our countryside avoids yet another blow.” At least 20 introduced pests and infections are attacking the UK’s native trees, with six at epidemic levels.
Nearly 50 others could arrive here soon, which could cost a further £1bn or more.
More than 60 million trees have been wiped out by Dutch Elm disease.
Other dangers include red band needle blight, which kills conifers such as Scots pine, and the pathogen Phytophthora austrocedri, which affects rare juniper.