Ash Dieback Cannot Be Fully Eradicated
November 11, 2012

UK Environment Secretary: Ash Dieback Cannot Be Eradicated

April Flowers for — Your Universe Online

The UK has been invaded — by a deadly tree disease. Ash dieback, also known as Chalara fraxinea fungus, has been identified at some 129 sites across the nation so far. Environment Secretary Owen Patterson acknowledged Friday there is no chance of fully eradicating the disease.

Paterson announced government efforts would focus on slowing the spread through the countryside, instead, by removing and destroying diseased young trees. An action plan formulated at a meeting of the government's emergency response committee, Cobra, states there are no plans to remove mature trees, which are important for wildlife. That news was welcomed by conservation groups. Efforts will instead be focused on developing resistance to the disease in new growth. Cobra is usually only convened for terrorist or other national security emergencies, underlining how serious this problem is for the nation.

"The scientific advice is that it won't be possible to eradicate this disease now that we have discovered it in mature trees in Great Britain," Mr Paterson said.

"However, that does not necessarily mean the end of the British ash. If we can slow its spread and minimize its impact, we will gain time to find those trees with genetic resistance to the disease and to restructure our woodlands to make them more resilient. Wildlife and countryside groups will play a major role in minimizing the impact of the disease and so will the general public, especially when it comes to spotting other areas where the disease has taken hold."

Paterson said the arrival of ash dieback meant that the Department for Environment, Food & Rural Affairs (Defra) would have to reconsider its priorities.

"If we are going to really do something radical on the way we handle our forestry in the future and change the priorities, we are going to have to shift resources within Defra. There will be some things we do in Defra now that we are going to have to stop doing."

The government's action plan also calls for encouraging landowners to help monitor the trees for signs of ash dieback. Newly planted diseased trees and infected trees in nurseries will be traced and destroyed. More than 100,000 have already been destroyed. Mature trees take longer to die, giving scientists vital clues for genetic strains resistant to the disease.

Simon Pryor, natural environment director of the National Trust, said, "We welcome the action plan but we are surprised the government is saying that it will not be possible to eradicate the disease. Given our limited understanding of this disease in this country, we believe we should keep an open mind as to whether it may be possible to eradicate it, or at least contain it within the core area in the east."

Defra chief scientific adviser Professor Ian Boyd said, "By next season, we could potentially have resistant forms of ash growing in this country.

"We need to put in scientific research to try and get genetic markers for resistance so that we can go out into our current woodlands that have not been infected and identify trees that might survive relative to those who might not survive."

The disease doesn´t seem to spread from tree to tree, but rather through leaf litter.

The government enacted a ban on ash imports and the movement of trees from areas with confirmed cases on October 29 after scientists confirmed that ash dieback had reached natural environments at sites in East Anglia. They have come under fire for waiting so long, however. The Horticultural Trade Association asked for a ban on ash imports in 2009.

The first cases were confirmed at sites in Norfolk and Suffolk as a result of spores from the fungus being blown across from mainland Europe, according to scientists. Computer modeling showed there were days when meteorological conditions existed that would have seen a spore plume across the UK.

The action plan is a "vital part of stopping the spread of this disease," said RSPB conservation director Martin Harper. "However, it is essential we do not divert resources away from other vital environmental services. Money must be found from central government coffers or we will simply be robbing Peter to pay Paul."

"Upland ash woodland and ash in the UK's lowland woods and hedges are important habitats for a wide range of plants and animals," he said.

"We are pleased that protecting this wildlife has been enshrined in the Government's approach to tackling ash dieback." Harper added this infestation should be a "wake up call."

"It is essential that we change the way we move animals and plants around the country and across international borders," he warned. "Regulation must be put in place to ensure this does not happen again - our natural environment is too precious."

Woodland Trust chief executive Sue Holden supports the government's position of leaving mature growth trees in place.

"This underlines widespread concerns that rapid and ill-considered action in our mature and ancient woods could do more harm than good," she said. "We do not want to remove small populations of resistant ash that may hold the key to the survival of the species across the country."

Trees with Chalara ash dieback have bleeding sores and cankers on the bark, with a discoloration of the underlying sapwood. The sores most often surround infected branches of the tree, causing dieback of shoots, twigs, branches and smaller stems. There are also blemishes on the leaves.

Even with all of this, the disease is not easy to identify because other tree diseases display similar symptoms. The Forestry Commission issued guidance on how to identify the disease for landowners and others, estimating there are almost 20 tree diseases currently in the UK.

Paterson cautioned against false hope, but said, "The great thing is ash reproduces quite quickly. If we know a small number of trees survived the very intense epidemic in Denmark [where 90% were infected], there must be hope here. What is regrettable is that I don't have a pot of magic potion to go up in a helicopter and spray on infected trees. There is no chemical we know of that kills this fungus."

Paterson criticized current European Union trade rules, "At the moment forestry and plant products are treated by the European Union as freely tradable products — is that really appropriate? We need to have a radical rethink. There are a number of very dangerous diseases out there which pose a real threat. I am prepared to consider radical proposals to protect the woodland environment and look forward to seeing Boyd's interim proposals at the end of November."