Tuesday, 18 June 2013

Phytophthora hits north Wales

Forestry Commission Map
29th May 2013
Walking through Coed y Bleiddiau I got to the end to find my usual route to Llyn Mair closed. Phytophthora! Not a swear word but the 'sudden oak death' curse killing trees in south Wales and now about to cause havoc up north. It’s also been confirmed at Tanygrisiau. How many other sites have been discovered in the past few days?

Phytophthora ramorum has been found in the larch trees below and above the railway line between Tafarn Trip and Campbell's Platform.

Infected parts of the forest are to be felled and walkers were being requested not to walk in the Maentwrog nature reserve to reduce the risk of spreading the disease BUT it's now been decided that that would be like shutting the stable door after the horse has bolted. There is an exclusion order covering the forestry plantation managed by Tilhill.

The following is the text of a press release from Natural Resources Wales on 25th June:

Natural Resources Wales has committed more than £2 million into the fight to deal with a disease which is attacking Britain’s larch trees.The new body, which looks after the Welsh environment, is to invest £500,000 straight away to combat Phytophthora ramorum (P ramorum) by cutting down trees around the edges of infected areas to try to stop it from spreading further.

The urgent strategy also includes a groundbreaking trial to see if injecting trees with a common herbicide could be effective in slowing the spread of the disease.

Natural Resources Wales will spend a further £1.7 million to remove infected trees, replant those areas and to build forest roads so that new areas can be cleared.

Trefor Owen from Natural Resources Wales said: “This response shows how concerned we are about this disease because of its impact on timber markets, the landscape, woodland and other habitats.We understand the anxiety this is causing the private forestry sector and communities in the affected areas. We are liaising with the Welsh Government and affected forest owners to see how the economic and other impacts can be minimised.”

The disease, which spreads through airborne spores from tree to tree, is proving difficult to contain and has moved more quickly than experts expected despite a massive effort to stop it in its tracks.Hopes of containing the disease have also been hit by one of the wettest summers on record and autumn weather conditions, which have been at the optimum for the spread of the disease. 

The full scale of the spread beyond the South Wales valleys to new sites in West, Mid and North Wales emerged during aerial surveys last month, which provided the first opportunity to assess the trees as they come into leaf. They also showed a rapid spread of the disease in England, Scotland and Northern Ireland, with a particularly dramatic increase in South-West Scotland.

The surveys identified 2,500 hectares (more than 6,000 acres) of new infection in Wales – about 2.5 million trees – taking the total area of infection in Wales to more than 5,000 hectares (12,300 acres) containing about 5 million larch trees.

Some 1,200 hectares (almost 3,000 acres) of larch trees have already been felled in Wales since the fungus-like organism was first discovered here in June 2010 in Welsh Government woodlands in the Afan Valley. Early signs that this extensive felling had contained the disease proved misleading, however, and a Wales Disease Management Plan was endorsed in 2012 by the Wales Phytophthora Outbreak Response Team (PORT), which includes the Welsh Government and other stakeholders.

This recognised that the disease could no longer be fully contained. It sought to slow down the rate of infection and reduce the environmental impact and costs of disease control by selectively felling trees in areas of light infection, rather than felling all the trees in infected areas.

However, the sudden, unpredicted increase in new infections revealed by the latest surveys indicates that this approach could not keep up with the spread of the disease and the Wales Disease Management Plan was reviewed this month.

Trefor Owen added: “Regrettably, the disease has spread much quicker than anyone expected despite all our efforts, so we are urgently looking into new ways of eradicating infected trees by injecting a common herbicide into the stem. We need to do this to try and slow the spread of the disease. This would also have to be done without causing further damage to the environment.We empathise with the concerns of private woodland owners and managers and will also be adapting some of the regulatory controls as the disease is now becoming endemic on the western margin of the British Isles and we believe the current strategy of containment is no longer viable in Wales.”

He said the timber from infected trees could still be used to produce a wide range of timber products.

The countryside remains open and the disease poses no threat to human or animal health. However visitors to woodlands can help reduce the spread of the disease by taking some simple actions such as removing any mud, plant material or leaves from clothing, boots, dogs and car tyres.

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