Deep in the forests of Poland, the tall trees suddenly vanish. A vast clearing opens up, a boggy landscape studded with the remains of dead ash trees. Half have been chopped to the stump, half are jagged like rotten teeth. The mystery fungus killed the leaves first, then moved into the stalk and down the trunk, cutting off the water supply and choking the tree. Then it rotted the roots.

By 2003, the fungus had moved into the older trees, some of which had been planted in the time of Stalin. Still the full horror of what was happening here was not revealed until one night in February 2007, when strong winds blew.

Prof Kowalski does not rule out the possibility that it was created by natural genetic mutation in the forests of Poland. However, a second theory is gaining more support in the scientific community.

“There are suggestions that Hymenoscyphus pseudoalbidus comes from Asia, where it lived on a different species of ash tree and caused no damage,” he says. “Then it came here, perhaps carried by the wind or by birds, or on clothes, and found the European ash more vulnerable.” Until the latest research is confirmed, he is not willing to say for sure. He does, though, think the row over imports in Britain is irrelevant now, or at least too late.

[He said] “Cooler temperatures in summer are better for some strains of the disease, so it is possible that the colder, wetter summer in Britain this year could have contributed to what is happening there. In most instances in Poland, we are finding that 15 to 20 per cent of trees do not die, and show no symptoms.”

“How many trees are at risk?” Eighty million. “Wow.” He looks shocked. “Has it been seen in the older trees?” It has. This experienced man of the forests puts his hand on his heart. “Then I am afraid it is over for you. It is too late. The game is over.”

http://www.telegraph.co.uk/news/worldnews/europe/poland/9669165/Ash-dieback-the-ruined-Polish-forest-where-deadly-fungus-began.html

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