Further cases of the tree disease Chalara, also known as ash dieback, have been confirmed in woodland in Sussex, Berkshire, Bedfordshire, Lincolnshire, Yorkshire and Northumberland after an unprecedented survey of Britain’s established woodlands.
These instances of Chalara are being discovered as a result of a rapid and intensive surveying operation carried out over the course of last weekend and the beginning of this week.
The discovery of the disease in these counties does not mean the disease is spreading rapidly. It is likely that the disease has been present in these areas for a number of years, originally caused by spores blown in from mainland Europe.
Plant health experts, in conjunction with volunteers from groups such as the National Trust and Woodland Trust have been examining around 2,500 blocks of land, each 10 kilometres square, where mature ash trees are known to be present in order to seek out traces of the disease in our established trees.
At the same time, plant health experts have been undertaking an urgent check of 220 prioritised sites which have had saplings from nurseries where Chalara was found to be present. Taken together, these surveys will give a much better picture of the extent of Chalara throughout the country, but will not have identified all cases of the disease; it is likely that more cases will emerge as checks continue.
Martin Ward, Chief Plant Health Officer said:
“We have thrown all possible resources at this surveying exercise which has given us a much clearer picture of the distribution of the disease to inform our evidence base.
“The science on Chalara is still emerging and the more evidence we have, the greater our knowledge and understanding of this disease and the better we are able to tackle it.
“I’d like to thank everyone involved in this survey. Together we’ve surveyed over 92 percent of England and all of Scotland and Wales so far -a tremendous achievement, especially in such a short time, which shows our combined determination to deal with Chalara.”
The ash tree is a native British species of tree, providing around five percent of all woodland cover. Chalara is a serious disease that has affected a high proportion of ash trees in northern Europe and it was confirmed as present in nursery stock in the UK in March.
A map showing all locations with confirmed cases of Chalara is available at www.forestry.gov.uk/chalara.