UK forests 'under unprecedented threat from disease'

John Vidal in the Guardian (UK): The UK's forests are under "unprecedented threat" from foreign pests and diseases, according to the government department responsible for the protection of forests and woodlands.

The ash dieback fungus found in East Anglia last week is just the latest invader to pose a serious threat to UK trees, and government ecologists say that more than 3m larch trees as well as thousands of mature oaks and chestnuts have been felled in the past three years to prevent similar fatal plant diseases from spreading out of control.

"We are under an unprecedented level of threat from a range of exotic pests and diseases, a lot associated with the international trade in live plants," said the Forestry Commission. "There are protections in place but the EU plant health regime is no longer fit for purpose. Too many pests and diseases are still getting through." More than 100,000 ash trees have already been felled to prevent the spread of ash dieback, or Chalara fraxinea, since the disease was identified in March.

..."We now have six to eight organisms in the British Isles that are a real concern. In the 1960s and 70s it was Dutch elm disease, which killed 30m trees; in the 1990s it was a new Phytophthora which devastated alders along riverbanks. But in the last 10 years we have had as many new diseases as we had in the previous 40 or 50 years," said Joan Webber, principal pathologist at Forest Research, the Forestry Commission's research arm....

An ash tree at the corner of Sod Wall Wood, East Riding, Yorkshire, shot by Keith Allison, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license