The sum brings together the cost of removing dead and dying trees and the value of the lost benefits provided by trees, including water and air purification and carbon sequestration.
The figures break down as:
- loss of ecosystem services: £9,407 million
- tree felling: £4,761m
- replanting: £560m
- loss of forestry and nursery profits: £80m
- research & surveys: £27m.
University of Oxford researcher and lead author of the study Dr Louise Hill said: "Nobody has estimated the total cost of a tree disease before, and we were quite shocked at the magnitude of the cost to society.
"We estimate the total may be £15 billion - that's a third more than the reported cost of the foot-and-mouth disease outbreak in 2001. The consequences of tree diseases for people really haven't been fully appreciated before now."
Woodland Trust senior conservation advisor and co-author of the paper Dr Nick Atkinson added: "To avoid further economic and ecological impacts, we need to invest more in plant biosecurity measures, including better detection, interception and prevention of other pests and diseases entering the country.
"We need to learn from past mistakes and make sure our countryside avoids yet another blow."
The authors recommend:
- a nationwide replanting scheme to replace lost ecosystem services, which would reduce the value of their loss by £2.5 billion;
- greater focus on, and investment in, biosecurity and sourcing of safe plant material to keep new diseases out;
- far tighter controls on imports of all live plants for planting.
The paper is published in the journal Current Biology.