Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what estimate she has made of the (a) geographical spread and (b) effect of ash dieback disease.

Surveillance and monitoring is carried out across the UK to provide intelligence on the rate of spread for Chalara and to help determine the extent of the disease. This work will continue on new infected sites and, in consultation with interested parties, the Government will consider what future surveillance work is needed.

Epidemiological modelling on the basis of current evidence suggests that the pathogen is likely to continue to spread in Great Britain, although there is likely to be noticeable regional variation, with areas in the south east, east and south west most affected. These predictions will need to be updated as additional information from ongoing research becomes available. The distribution of confirmed findings is published weekly by the Forestry Commission on its website and shows the precise coverage so far. I attach the latest map here but further updates can be found by using the following link.

http://www.forestry.gov.uk/chalara#Distribution

The impact of Chalara infection depends on tree age, provenance or genotype, location, weather and microclimate conditions, and presence of honey fungus (Armillaria) or opportunistic secondary pathogens. Trees in forests are likely to be more affected because of the greater prevalence of honey fungus and favourable microclimates for spore production and infection. Trees cannot recover from infection, but larger trees can survive infection for a considerable time and some might not die.