One of the UK’s most senior authorities on trees, Clive Brasier, said Britain’s trees were under relentless and systematic attack from a host of diseases.
Invasive organisms could adapt and strike chestnut, alder, larch, Corsican pine, beech and oak, the professor at Forest Research warned in the Daily Telegraph.
Pests ranging from bleeding canker, sudden oak death and red band needle blight were killing trees from woodlands, riverbanks and lowlands.
Brasier said international protocols governing the trade and movement of trees and root stock had not been properly revisited since the 1950s and were now inadequate.
"The trade in plants is now highly globalised and yet most European nurseries and plant-health organisations have little knowledge that they may be harbouring exotic Phytophthora pathogens," the article said.
Brasier called for international protocols on the trade in plants and trees to be overhauled "urgently and comprehensively" to control movement of material.
The RHS and journalists should educate people and the plant-nursery trade on the risks of imports, and lobby MPs on what they planned to do "to save our trees".
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