It only needs one infected tree to escalate prevention into a full-scale control firefight that we are unlikely to win. Somewhat surprising then that a daily stream of lorries from continental Europe is delivering hundreds of trees directly into UK landscapes with no credible regulation against this lethal threat.
There is a ban on trees from known infected areas and obligatory plant passports as proof, but is that really enough against a pest that can persist in soil and on wood as invisible spores with a virulent capacity for infection?
This has parallels with oak processionary moth, which arrived on continental trees planted without adequate biosecurity scrutiny. The original Government strategy of eradication was a nonsense, leaving the last resort of control at huge cost.
All this could have been avoided had imported trees been quarantined for a year before planting out. Lord Framlingham recently raised this in a Lords debate, referencing Barcham’s biosecurity policy (www.barchampro.co.uk/barcham-trees-biosecurity) as good practice.
However, that is a unilateral initiative, and no other significant importers have followed suit, confirming that a voluntary scheme will not succeed.
Free trade has obvious benefits but when the price might be our capital city without plane trees for a generation perhaps that is a risk too far.
Fingers crossed and hoping for the best has worked up to now, but time is running out. If compulsory quarantine does not happen soon, then London could lose part of its iconic green character that no amount of mayoral election promises will replace.
Jeremy Barrell is managing director of Barrell Tree Consultancy