Ash dieback... the truth!

It's all doom and gloom isn't it, with headlines such as "Infection sites have doubled within a month" (Guardian), "Ash dieback fungus could devastate endangered species" (Telegraph), or "Ash dieback beyond control" (Channel 4 News). But is it really all catastrophe? Not according to the informative, reliable, (and rather wonderful), BBC Radio 4 programme More or Less.

The truth is somewhat different from the disaster scenario painted in the news. Whilst there certainly is a problem, the tendency is to cite the worst case figures from Denmark, where the disease has been present for some time. There, 90% of ash trees are infected, with possibly as low as 2% being resistant.

In fact the range of infection throughout Europe is typically 70%, with up to 20% of ash trees being resistant. Serious enough, but not the wipe out presented to the public.

But what about all those new infection sightings within the UK? Actually, many of them are not new and might have been present for up to two years... it's just that scientists have started looking over the last few months and finding them. In fact ash dieback doesn't spread after October. The spores causing the problem migrate from fallen leaves and stems from June to October. Every new dot on the infection map from November onwards is probably an existing infection, and not new. The disease spreads at a rate of 10 to 20 miles a year, so hardly the sudden mass, country-wide infection imagined in the press.

No ancient British ash trees have been felled. Those removed to date have been young trees from nurseries and plantations. And what about the headline that 30% of British trees could be affected? Hard to understand, when only 5% of British trees are ash!

If you want to get to the truth of the figures, and just how wrong they can be, you couldn't do better than listen to More or Less.

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