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Government considers ban on ash tree movements

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  Chalara dieback of ash - browning of ash leaf tip caused by Chalara fraxinea fungus

Issued jointly with Fera

The United Kingdom Government is considering legislation to ban the movement of ash trees from areas where the destructive Chalara dieback disease of ash trees might be present, the Forestry Commission and the Food & Environment Research agency (Fera) announced today.

The announcement follows the discovery of ash trees infected by the Chalara fraxinea fungus in several nurseries and recent tree planting sites in England and Scotland. The infected plants had come from nurseries in continental Europe, or had been in contact with ash plants imported from the Continent. The Forestry Commission, Fera and the Scottish Government’s plant health team are requiring the destruction of all infected ash plants before the disease has a chance to become established in the UK. Plant health authorities in Wales and Northern Ireland are also on high alert for the disease, and Dr John Morgan, head of the Forestry Commission’s Plant Health Service said:

“The UK’s trees, woods and forests play a hugely important role in our environment, landscape, culture, industry and health and well-being, and we must do everything we can to protect them from threats such as Chalara dieback of ash.

“Chalara dieback is the single biggest threat to our native broadleaf trees since Dutch elm disease wiped out tens of millions of elm trees from the 1960s onwards. The Government is taking precautionary action now to prevent a recurrence of that situation and to protect our landscape, industry and wildlife.”

The Government, through Fera, is consulting on a pest risk analysis for Chalara fraxinea drafted by scientists at the Forestry Commission’s Forest Research agency. The consultation period closes on 26 October, and this process will produce recommendations to the Government about managing the threat to the UK’s ash trees. Dr Morgan explained:

“One option Ministers are considering is to legislate to restrict movement of ash plants so that they can only be moved from areas known to be free of the disease. In doing so the Government will take into account evidence received during the consultation process, but our aim is to prevent the establishment of this disease. In practice this will mean a suspension of imports into and movements within Great Britain until there is sufficient evidence that they can safely resume.

“We are making this announcement now to signal the Government’s intentions to businesses which grow or trade in ash plants.

“The international trade in live plants poses the risk of pests and diseases accidentally entering the UK from abroad. For that reason the UK is also fully engaging in the review of the European Union’s plant health regime to ensure that it is fit for purpose in the 21st-century global trading environment.”

Further information about Chalara dieback is available on the Forestry Commission’s website at The Pest Risk Analysis and details of the consultation are available in the consultations pages of the Fera website at


Notes to Editor:

  1. If legislation were introduced it would be in the form of a Statutory Instrument covering movements of ash planting material into and within Great Britain, with equivalent legislation in Northern Ireland. Defra news release

  2. The trade in ash plants between EU Member States is not subject to plant health controls because, until now, ash trees have not caused concern in terms of the pests and diseases they might carry. However, EU Member States, such as the UK, may pass national legislation to restrict imports of plants and plant material to prevent the accidental importation of tree and plant pests and diseases if they can demonstrate that they are free of the pest or disease concerned. They can seek approval for their territory, or parts of it, to be declared Protected Zones into which the relevant plants or plant materials are subject to additional requirements. The fact that no cases of Chalara dieback have yet been found in the wider natural environment in the UK outside nurseries and recent plantings of young ash trees, and the fact that the we are working to eradicate the disease from those sites, means that national legislation is justified. The UK Government would be the first government of an EU Member State to consider such legislation, although in many other Member States the fungus has spread so fast and so widely that national legislation to prevent its entry would be too late.

  3. The Horticultural Trade Association (HTA), the trade body for the garden industries, on September 18 called on its members to practise a voluntary moratorium on importing ash plants in a bid to reduce the risk of any further accidental introductions of the disease. The press release calling for the moratorium is available on the HTA website .

  4. The Institute of Chartered Foresters (ICF) on 2 October announced that a group of leading forestry companies and organisations were to work together to develop a voluntary ‘chain of custody’ scheme to provide reassurance to plant buyers that their plants are free of diseases. The press release announcing this is available on the ICF website.

  5. Plant health authorities are issuing statutory Plant Health Notices on the owners of infected trees requiring them to destroy the plants. Other plants from the same consignments are being traced forward to their eventual buyers, who are being required to destroy them.

  6. Ash trees with disease symptoms now believed to have been caused by C. fraxinea were first reported in Poland in 1992, followed by further reports from many other European countries in subsequent years. The causal agent of this disease is an ascomycete fungus which is characterised by two stages. The asexual stage, C. fraxinea, was first formally 'described' by scientists in 2006 and is not thought to be involved in its reproduction. The sexual stage, Hymenoscyphus pseudoalbidus (H. pseudoalbidus), was only described and confirmed as a new species in 2010. It is the spores from this stage which are thought to be responsible for its reproduction and dispersal.

  7. For a time, scientific evidence indicated that the sexual stage of the fungus was the native European species Hymenoscyphus albidus (H. albidus), and one suggested reason for the outbreak of disease in Europe was that environmental changes might have caused this previously benign organism to become damaging to its host plant, ash.  H. albidus is endemic and widespread throughout continental Europe and the British Isles and therefore, during the period when it was implicated as the pathogen associated with ash dieback, it was not feasible to tackle the disease by means of EU or national regulation. The origin of the new species H. pseudoalbidus, which is now recognised as the sexual stage of the C. fraxinea pathogen, is not yet known.

  8. Common ash (Fraxinus excelsior) is a deciduous species native to much of Europe, including the British Isles. After oak and birch, it is the third most common native broadleaf tree in Great Britain. Ash timber is a dense, strong but flexible, easily worked hardwood which was traditionally used for making tool handles and furniture. Usage has declined in these markets because of the advent of other materials, but the timber is still sought after for flooring and high-end, bespoke uses. It also makes excellent firewood, smoking wood and barbecue charcoal.

  9. Government departments and agencies from across the UK, working with partners in the private and third sectors, have drawn up a Tree Health and Plant Biosecurity Action Plan to ensure that the UK's defences against tree and plant pests and diseases are as robust as possible.

  10. Media contact: Stuart Burgess, 0117 372 1073,