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Chalara comes to the North West

By Keith Jones,
North West & West Midlands Area Director, Forestry Commission England

As many readers will already know, the first cases of Chalara ash dieback in trees in the wider environment in North-west England have been confirmed.

Until this year, the region’s only cases of the disease, which is caused by the Chalara fraxinea fungus, had been found in young, recently planted ash trees. In all cases we worked with the Food & Environment Research Agency (Fera) and the owners to remove and destroy the plants involved before they could infect trees in the wider environment.

Sadly, however, more than 50 locations of infected trees in the wider environment were confirmed this year. Most of them are widely distributed across Lancashire, with the known extent of the cluster extending into southern Cumbria, greater Manchester and western North Yorkshire, including the Yorkshire Dales National Park. It is not clear how the infection came to the area, but the two main routes for spreading the disease are in the form of spores blown on the wind or on infected plants brought into the area for planting and which begin to produce spores.

Chalara - classic stem lesion on young tree

The first of these cases were spotted by chance by our regional Plant Health Officer, Barnaby Wylder, and many of the remainder were discovered during follow-up surveys by contractors trained to recognise the symptoms. In most of our cases in the region the infection is at a low level, and symptoms are still very subtle and can be easy to miss by an untrained person.

Chalara, as a wind-blown disease, was inevitably going to arrive in the region eventually, but it is nevertheless very disappointing that we have this number of cases already.

We will do all we can to support woodland owners with practical guidance and advice on topics such as how best to respond to the disease and what species of trees they can plant to replace lost ash trees.

I do want to clarify that owners of infected ash trees do not have to fell or destroy them unless they become unsafe. We cannot eradicate the disease once it gets into the wider environment, and dead and dying trees continue to make a contribution to wildlife habitat, biodiversity and a varied landscape.

In addition, keeping the trees standing can help us to spot any which might have some tolerance or resistance to the disease, which could help our scientists’ efforts to breed future generations of Chalara-resistant ash trees.

We welcome reports of suspected Chalara ash dieback in new areas via our Tree Alert on-line pest and disease reporting tool. Video and pictorial guides to the symptoms, access to Tree Alert, and maps of the current known distribution of the disease are available on our website. We recently added an interactive map of Chalara distribution to the website, so that users can bring up more information by zooming in and using toggle tools.

Meanwhile, responding to the growing need for well informed management of tree pests and diseases, local woodland and forestry stakeholders have formed a North West England Tree Health Group, building on the existing Cumbria Tree Health Group. The group brings together a wide range of organisations and individuals from the private, public and not-for–profit sectors with an interest in the region’s trees and woodland.

The new group has formed an Ash sub-group, which is co-ordinated by Cumbria Woodlands, and which is developing a regional action plan to develop and share best practice for managing Chalara in the region.

Anyone interested in hearing more on tree and woodland health and in contributing to a sustainable future for the region’s trees, woods and forests should register their interest.
On 10th December the North West Forest Forum is holding an event focusing on Tree Health – spaces are still available.

Meanwhile, we have not yet found any wider-environment cases in the West Midlands, although we did recently confirm a case in young, recently planted trees on a site managed by Birmingham City Council.

Last updated: 17th November 2017