Ash dieback (Hymenoscyphus pseudoalbidus, commonly referred to as Chalara fraxinea)

Ash dieback is a serious disease that has affected a high proportion of ash trees in northern Europe. Its presence within the UK was detected in 2012 and since then a growing number of cases have been confirmed in nurseries, recent planting sites and the wider environment.


Anyone wishing for more information on identifying the disease, guidance on managing ash trees or the latest outbreak maps should go to the Forestry Commission website. Defra priorities for managing ash dieback are available within the Chalara Management Plan.


JNCC is supporting Defra and the Devolved Administrations in understanding how biodiversity is likely to be impacted by ash dieback, how important these impacts are, and the means for monitoring and mitigating any biodiversity changes.


JNCC has pooled resources with Natural Resources Wales (formerly Countryside Council for Wales), Defra, Department of the Environment Northern Ireland, Forestry Commission, Natural England and Scottish Natural Heritage to produce two new research reports:


A short overview of both of these reports, summarising the key findings, will be available in early February.


JNCC has produced an initial assessment of where there are important ash locations in Great Britain.  Important ash is defined as where it is a significant and hard to replace or re-create semi-natural feature with a strong role in ecosystem functioning.  This assessment will be updated in March 2014.


The picture of the total resource of ash in woodlands above 0.5 hectares is available from an analysis by the Forestry Commission of the National Forest Inventory


The picture of the total resource of ash in small habitat patches <0.5 ha and also trees outside woodland as individual trees or in hedgerows and woody linear features, is available from an analysis by the Centre for Ecology and Hydrology of the Countryside Survey:




Page updated  28/02/2014