New project to protect Westonbirt Arboretum’s ancient woodland

New project to protect Westonbirt Arboretum’s ancient woodland. 

Forestry England experts at Westonbirt, The National Arboretum have today announced a new project to help safeguard the ancient Silk Wood (which makes up around two-thirds of the Arboretum) from pests and diseases, most notably chalara ash dieback. Forestry England will be removing trees infected with chalara ash dieback, to make way for a wide variety of tree species that are more resilient to pests and diseases. 

Since first being discovered in the UK in 2012, chalara ash dieback has infected common ash trees (fraxinus excelsior) in every English county. Caused by the fungus Hymenoscyphus fraxineus, it thins the tree’s crown, and can ultimately lead to the death of the tree. There is no cure and it is exceptionally difficult to prevent the spread of the disease since it travels on windborne fungus spores. This project undertaken by the National Arboretum will help to keep the ancient woodland healthy in future years, and will help others manage the impact of chalara ash dieback in their woods and forests across the UK. 

Though the project will mean the ancient Silk Wood will look and feel very different, it will ultimately result in a healthier woodland that is more resilient to pests and diseases. Some older ash trees can live for a long time with the disease, but as the infection spreads through the tree, the wood becomes increasing brittle, making it more and more dangerous for staff to remove. Therefore, we must act now to safely make room for the new trees that are critical for the long-term health of the woodland.  

Mark Ballard, Forestry England’s Curator at Westonbirt Arboretum said: 

‘Chalara ash dieback is a relatively new disease to the UK and this project presents us with an important research opportunity to learn more about how best to manage woodlands infected with chalara and how to mitigate the loss of ash trees in our woodlands through replanting; the results of this project will be shared with woodland managers in the UK and abroad. In some areas of Silk Wood we will be retaining common ash (fraxinus excelsior) looking for natural tolerance and how the disease progresses, whilst in other areas we will be removing all infected ash to make way for new plantings of species that are more resilient to pests and diseases. Though we cannot say for certain what species we will be replanting, these are likely to be broadleaf natives from different provenances, and potentially some near natives. 

To start with we will remove around 200 ash trees from Silk Wood, but the majority of the removal work will start next year, and will continue in phases for a couple of years.  Replanting will begin next year, and we are hoping to involve the local community in this in some way.’  

To help inform the public about the project, Westonbirt have also launched a special trail for the autumn, where visitors can find out more about the impact chalara ash dieback is likely to have on the UK landscape and what they can do to help. 

Ben Oliver, Learning and Participation Manager at Westonbirt Arboretum, said:

‘A crucial part of our role here at Westonbirt is to help people understand how important trees are and the threats that they now face. This project is an ideal opportunity to do just this, and the trail also provides a chance for the public to tell us how these changes make them feel. Westonbirt Arboretum is a special place for many people and we are incredibly sad to be losing so many of our beautiful ash trees – we wanted to give people the chance to express their feelings at the threat that ash trees now face.’ 

Visitors can help limit the spread of this and other pests and diseases by: 
•    Cleaning mud and debris off shoes, pet’s paws and tyres after a walk in the forest, which prevents pests and diseases spreading. 
•    Not bringing plant or tree products back from trips abroad, because these can carry harmful non-native tree pests or pathogens.
•    Being vigilant! The public can report any trees that they suspect are in ill-health to Forestry Research using Tree Alert: 

Notes to Editor

1.    Westonbirt, The National Arboretum is managed by Forestry England and is renowned worldwide for its tree and shrub collection. Home to five national collections, the arboretum covers 243 hectares (600 acres) and contains nearly 15,000 labelled specimens. Visitor numbers are 500,000 a year, with a membership of over 32,000. Westonbirt Arboretum was established in the 1850s by wealthy landowner Robert Holford and later developed by his son George Holford. Unlike many arboretums, Westonbirt is laid out according to aesthetic appeal rather than scientific or geographical criteria. Visit 

2.    Forestry England manages and cares for the nation’s 1,500 woods and forests. As England’s largest land manager, we shape landscapes and are enhancing forests for people to enjoy, wildlife to flourish and businesses to grow. We have around 1,000 staff, 20,000 volunteers and 80,000 members. For more information visit Forestry England is an agency of the Forestry Commission. 

3.    Chalara ash dieback is a fungal disease affecting the common ash tree (Fraxinus excelsior) and other Fraxinus species. It is caused by a fungus called Hymenoscyphus fraxinus which is native to eastern Asia. The disease is now widespread in Europe, where it has been observed damaging ash trees since the 1990s. It was first observed in the UK in 2012, although subsequent research found sites where it has been present since at least 2005. Though a small percentage of ash trees will be tolerant to the disease, it is likely to cause significant damage to the UK’s ash population. 12% of broadleaf woodland in Great Britain is ash, there are a further 60 million (estimated) ash trees outside of woodlands in the UK, and 955 wildlife species are associated with ash. Defra have recently published a leaflet, summarising guidance for owners of ash trees and land managers on how to identify and mange infected ash trees: 

Media Contact: 
Rebecca Hare, Marketing and Communications Manager, Westonbirt, The National Arboretum 
t: 0300 067 4152