Some of the plant biologists working on ash dieback believe that the same organism has now become pathogenic because of changing cultural conditions, atmospheric pollution, drought stress, nutrient overload, unseasonal rainfall, or absence of limiting factors such as frost.

One way we could try to protect our ash trees might be not to let this year’s leaves rot down, but to rake them up and burn them, keeping the ground under the trees clear. This might be a waste of time but it must be worth a try. We are more likely to be told to mulch the leaves, burning of woodland debris now being frowned upon, but burning is a surer way of eliminating a fungal pathogen.

Unaffected trees have been found growing alongside dead and dying trees. Some individuals, perhaps as many as 20 per cent of a population, are naturally resistant. What this suggests is that we should be selecting and breeding ash trees with this genetic trait to replace the ones we are certain to lose. the virulence of the disease may well decrease in time.

require both Railtrack and the Highways Agency to monitor the ash trees growing in their many miles of verges and embankments, and remove juvenile ashes in the understorey. Fungal spores are not just carried on the wind; they are also transported by vehicular traffic.