Defra updates Chalara policies

With spring finally approaching, the threat of Chalara to ash across the UK is greater than ever. As mentioned in a previous post, the fungus that causes the disease lies dormant over winter, and sporulates in the spring. Increases in temperature are therefore likely to initiate further spread of the disease. Actions over the next few months will be vital, and different strategies could give very different outcomes for our woodlands and forests. An updated approach to management of ash dieback was published by Defra at the end of March, in a ‘Chalara Management Plan‘.

The plan provides an update to the interim control plan published by Defra last December. In finalising the document as a management plan, Defra have concluded that Chalara is no longer a disease that can be stopped or prevented, but one that needs to be managed and controlled carefully. Its timely publication before the potential start of Chalara spreading across the country shows that the true threat of the disease is recognised. Publishing the plan just before Parliamentary recess, however, does little to highlight the problem of tree disease to all in Parliament. This isn’t an isolated issue for Defra, and many constituency areas will be greatly affected by potential losses of trees.

The four key objectives outlined in the interim plan still remain:

• Reducing the rate of spread of the disease;
• Developing resistance to the disease in the native ash population;
• Encouraging landowner, citizen and industry engagement in surveillance, monitoring and action in tackling the problem;
• Building economic and environmental resilience in woodlands and in associated industries

Further means to achieving these have been presented, along with associated timelines. There is a focus on the implementation of resistance research through both lab and field work, and the removal and replacement of young diseased trees.

The announcement of financial assistance for landowners who will need to re-plant areas or move to different timber crops is a novel component of the plan. This type of support is rare for tree disease. In 2011, thousands of larch trees in south west England were felled, at the cost of the landowner, to try and prevent the spread of Phytophthora ramorum. Providing support for the removal and replacement of ash is one way in which to achieve both the latter objectives outlined above. This will engage landowners in the issue, and ensure that effective barriers to spread are present. This decision is especially relevant to this species, as 97% of ash woodland is in private ownership.

As of 8 April, there are over 400 cases of Chalara in the UK. 249 of these are in newly planted areas, and 19 are in nursery sites. The actions outlined in the Chalara Management Plan target these areas, rather than established sites. The plan emphasises that:

“There is currently no need to fell veteran, ancient, or mature ash trees as a result of them becoming infected with Chalara as they could take many years to die. Dead and decaying wood is also beneficial for some wildlife species that depend on ash. Veteran, ancient mature trees are also important components of a resilient woodland or landscape. They will also provide potential for resistant regeneration.”

The implementation measures in the plan relate to England only. Separate plans are being developed by each of the Devolved Administrations. Northern Ireland is working with the Republic of Ireland to give a coherent Ireland-wide plan. Both Scotland and Wales are developing plans that will complement measures taken in England.

A revised version of the management plan will be published by the end of March 2014. This will provide updates for non-woodland trees and give a longer-term view. Recommendations from the Plant and Tree Health Independent Task Force about how the threats to trees from pests and pathogens could be addressed will also be incorporated. These are due to be released next month.