Imagine heading out West with a pair of binoculars and unexpectedly coming across a pair of passenger pigeons, birds that have been extinct for decades? Or imagine driving into the South African Veldt and coming across a Quagga? Ludicrous thoughts I know, but still sometimes the thought occurs; how can the scientists be so sure a life form has become extinct, never to be seen again?

Ever since I was a young boy, I have had an abiding passion for trees. I can’t tell you quite what sparked this interest, although I remember being upset at plans to fell a large number of trees around my old school. So upset in fact that I went around with a friend scraping as many of the painted crosses from the trees which were doomed that we could find.  Remarkably, we did succeed in saving one tree, a graceful Cypress that to my knowledge stands to this day.

When I was growing up, the English Elm was coming down – in its millions. A dread disease had struck, a more virulent form of something that was called “Dutch Elm disease”, succeeded in killing almost 25 million Elm trees, the vast majority being English Elm. The disease is born by flying bark beetles, which carry with them deadly fungus spores. Once those spores have worked their way into the sap carrying vessels that keep the trees alive, they wither and die. This new virulent variety of the disease, so named because Dutch scientists conducted much of the early research, came via imported logs from North America.

A cordon sanitaire was established around the coastal town of Brighton, and to this day many fine Elm trees may still be found, including possibly the oldest English Elms in the World. But elsewhere in the country, the tree has disappeared. The young suckers it throws up tend to get diseased as soon as any sapling gets to fifteen foot or so.

So imagine my surprise and wonder, when I heard rumours of two English Elm survivors in a remote part of Gloucestershire. To begin with I didn’t believe them. How could there be any survivors – these must surely be one of the other varieties of Elm that have at least a degree of resistance to the disease? Intrigued though, I took myself off yesterday, driving with a friend through the stunning Cotswolds countryside, basking in the warm rays of mid August.

And there they were! Two English Elms, standing in all their glory, and at least a couple of hundred years old. Thick with foliage, their cracked bark and huge boughs intact, these giants had miraculously survived. Perhaps it is their isolation. Perhaps it is because this was never really Elm country and there were never that many around to contaminate them.

And then looking up into the crown of the younger tree, I noticed the tell tale sign of an early ‘aerial’ attack of Dutch Elm disease. The disease is still about, and has been especially bad this year because the hot summer has encouraged the beetles to breed.

There is time to act. If this diseased bough is removed speedily, the disease may be caught. If not, these last two veterans of an army once 25 million strong will soon resemble wintry skeletons in a green summer landscape. The picture here does not really do these trees justice – but in the coming weeks, now I have alerted both the local villagers and various conservation bodies, we may just save the Elms. Sadly it is too late to do the same for the passenger pigeon or the Quagga.