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NEWS RELEASE No: 1381916 JULY 2010

Forestry Commission leading fight against killer tree disease

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The Forestry Commission is continuing to lead the fight against the tree disease, Phytophthora ramorum, that has been infecting Japanese larch trees in forests across the South West.

Acting on the best available scientific advice, the Forestry Commission is carrying out a programme of felling infected trees on public and private land as the most effective means of controlling further spread of the disease.

A current large-scale example of such felling for disease control is now underway on land managed by the Forestry Commission in the Glyn Valley in Cornwall. Further felling operations are also in train in Plym Woods on the edge of Plymouth; Lydford on the edge of Dartmoor.  Felling will also soon start at Burrator Reservoir on Dartmoor, which is managed by South West Lakes Trust.

The Forestry Commission is repeating its earlier requests to landowners and woodland managers to remain vigilant and boost our efforts to contain the disease by reporting any suspected signs of infection in their woodland.

Chris Marrow, Forest Management Director from the Forestry Commission’s Peninsula district said:

“No one, least of all the Forestry Commission, wants to see trees and woodland cut down unnecessarily – ahead of their natural time for harvesting - and leaving exposed bare landscapes on a scale greater than through routine, planned rotations.  Unfortunately, our scientific advice is that felling infected trees is the best method for controlling this disease and so preventing further damage.

We are seeking to minimise the impacts of this highly infectious disease on landowners and the landscape as best we can – simply by seeking to contain it.  But also from the outset, we have been working closely with private landowners and their representative bodies to keep them informed about the disease, the symptoms to look out for, and to explain and agree the necessary control and biosecurity measures .  For owners who find they have infected trees we have  secured a limited fund and depending on the progression of the disease we may have to target support to sites that pose the greatest risk of spread to uninfected areas.
We have been greatly assisted by the vigilance and support of private woodland owners in helping us detect and seek to limit the spread of this disease.”

The Forestry Commission is acutely aware of the potential negative economic impacts this disease could have on the forest sector overall and individual woodland owners in particular. Hence our urgent and ongoing efforts to stop the disease spreading further.

In addition, working with colleagues in Defra and Fera, we have put together a support package with limited funds to help woodland owners having to contend with the disease and its impacts, including:

  • Setting up a network of agents who can provide professional advice and practical expertise for owners having to carry out felling for disease control
  • Providing financial support for the clearing of infected immature Japanese larch trees which are too small to have any commercial value for timber.
  • Getting agreement from saw mills to accept timber from infected mature trees felled for disease control – so enabling owners to achieve some income return on their costs. This has been done on the basis of scientific advice establishing that there is minimal risk of disease spread from transporting and processing logs from infected trees – as long as biosecurity measures have been followed.

Chris Marrow continued:

“In affected forests such as Plym Woods, visitors can help us with biosecurity by following some simple guidelines displayed on signs in the forest.  This includes keeping to the stone paths, keeping dogs on short leads and cleaning footwear and bikes before leaving the forest.  We want people to continue enjoying the woods but by taking these small steps they will help enormously in our fight the spread of the disease.  Of course, there will be some parts of the forest that will be out of bounds while we carry out felling but we will work hard to keep any disruption to the public to an absolute minimum.  People familiar with our woods will be used to this as all of our forests are working, sustainably managed forests, which means a regular cycle of felling and planting.

“Private landowners also have a big part to play.  We need them to remain extremely vigilant and regularly inspect their own woodlands where they have Japanese larch.  It is essential that any suspected P ramorum outbreak is reported to us.  There is a range of advice and help available to landowners on the Forestry Commission website  We are here to help and people with any concerns can contact us at any time to discuss any issues they are having.”



  1. The disease was first discovered by the Forestry Commission to have jumped from its previously known main host, Rhododendron, to Japanese larch in Autumn 2009. We immediately initiated a rapid survey across Forestry Commission woodland in the South West, which identified 14 additional infected sites.   In recent months, we have undertaken a detailed and extensive programme of aerial surveys covering the whole of the west of the country – running from the South West, through Wales and up into Western Scotland.  These surveys have identified 230 suspicious sites across England and Wales of which 36 have confirmed infections. 

  2. Suspected infections should be reported to:
    • in South West England - Forestry Commission England, Mamhead Castle, Mamhead, Nr Exeter, Devon EX6 8HD; tel: 01626 890666; email:;
    • in woodland elsewhere – the Forestry Commission’s Plant Health Service on; tel: 0131 314 6414;
    • in non-woodland trees such as those in gardens, parks, streets and farmland - Forest Research’s Disease Diagnostic Advisory Service; tel: 01420 23000.  Further enquiries can be made by emailing, for trees found south of the Humber-Mersey line, and for enquiries north of there.
  3. P. ramorum infection has been confirmed in Japanese larch trees (Larix kaempferi) in woodland managed by Forestry Commission Wales in the Afan Valley near Port Talbot, in Garw Valley near Bridgend, and the Vale of Glamorgan. In South West England it has been confirmed in a mix of Forestry Commission England and privately owned forests, including the Commission’s Largin Wood in Cornwall, Plym Woods east of Plymouth, and Canonteign Woods near Exeter.

  4. P. ramorum has not been found on any trees in Scotland.

  5. P. ramorum can be spread on footwear, vehicle wheels, tools and machinery, by the movement of infected plants, and in rain, mists and air currents.

  6. Infected plants such as rhododendron are usually destroyed by burning or deep burial. Infected trees are usually felled to kill the living plant tissue on which the pathogen depends.

  7. P. ramorum is a ‘quarantine’ organism under European Union law and its presence on trees or woodland plants must be notified to the relevant authorities (Forestry Commission, Fera, Scottish Government, and the Welsh Assembly Government).

  8. Infected Japanese larch trees produce particularly high numbers of the inoculum that spreads the disease – five times the level produced on rhododendron - meaning the disease can quickly affect a large number of trees and shrubs.

  9. P. ramorum has not been found infecting any European larch (Larix decidua) or hybrid larch (Larix x eurolepsis) trees, but these species are being kept under close surveillance.
    11. Complete figures are not available for Japanese larch alone, but all three larch species together cover an estimated 134,000 hectares in Britain, or about 5 per cent of total woodland. Individual country figures are:
    • Wales – 23,000ha / 8 per cent;
    • England – 47,000ha / 4.3 per cent;
    • Scotland – 65,000 ha / 5.1 per cent.
    (To convert hectares to acres, multiply by 2.47)

  10. Larch is a durable, versatile timber that tolerates changes between wet and dry conditions very well, and resists rotting when used in the ground. It is therefore in demand for outdoor uses such as fence posts, fence panels, exterior wall cladding, boats, sheds and furniture, as well as indoor uses such as flooring and chipboard. It is easily stained, worked and finished.

  11. P. ramorum causes the disease known as “sudden oak death” in the USA, where it has killed millions of American native oak and tanoak trees in California and Oregon. However, that populist term is not appropriate for Britain, as laboratory tests have shown that Britain’s two native species of oak, sessile and pedunculate (or ‘English’) oak, are much more resistant to it than their American cousins. Only one sessile oak has been confirmed with P. ramorum infection in Britain.

  12. P. ramorum should not be confused with acute oak decline (AOD), which is a separate disease affecting oak trees in the Midlands and parts of Wales and South East England, and in which a newly discovered bacterium species appears to be involved.

  13. For more detailed information please visit

  14. MEDIA CONTACTS:For pictures, and information about P. ramorum in:
  • Forestry Commission South West England – Kirstie Smith, 01392 834249
  • Forestry Commission England – Stuart Burgess, 0117 372 1073;
  • Forestry Commission Great Britain  (Plant Health matters in general) – Charlton Clark, 0131 314 6500;
  • Dartmoor National Park Authority – Mike Nendick, 01626 832093
  • South West Lakes Trust – recreation queries re Burrator – Tommy Haydu, 01566 771930
  • South West Water (water quality queries) – press office, 01392 443020