Public urged to check a sweet chestnut tree to safeguard its future

The Royal Horticultural Society (RHS) is calling for members of the public to urgently monitor sweet chestnut trees during National Tree Week (26 November – 4 December 2023) to help safeguard it for future generations to enjoy.

Volunteers are being asked to look for signs of disease, the oriental chestnut gall wasp or if the tree is healthy and then report their observations.

Unfortunately, sweet chestnut trees (Castanea sativa) - one of the country’s most iconic trees, found alongside roads, in parks and woods - are facing a growing threat from two devastating problems: the oriental chestnut gall wasp (OCGW) and a fungus, chestnut blight. To help tackle their plight, the RHS, Defra, Animal and Plant Health Authority and Forest Research have joined together to call for the public to check a sweet chestnut tree where they live and to report any signs of disease or where the trees are healthy. 

As sweet chestnuts drop their leaves at this time of year it is a particularly good time to look for signs of disease. Getting involved in the project is easy and all records must be submitted by the end of National Tree Week (26 Nov – 4 Dec 2023). Using the information on the RHS website volunteers can simply identify a sweet chestnut tree; look for signs of sweet chestnut blight or oriental chestnut gall wasp; take photos of the tree and go to Tree Alert, the official government reporting tool for tree health, and fill in a report.  

Signs to look out for include distorted leaves or buds with swellings (galls), a sparse tree crown and sunken, cracking or discoloured bark. Please visit the RHS website for full details:

It is just as important to report healthy trees, showing no signs or symptoms of OCGW or chestnut blight. Together the reports will inform Forest Research scientists of where affected trees are, as well as the proportion being affected. The data will be used to create a national map of the health of sweet chestnut trees across Britain, which will help target future conservation efforts and help to protect the sweet chestnut tree.

The threats posed by chestnut gall wasp and chestnut blight are significant. The OCGW lays its eggs inside the tree’s buds, causing abnormal growths, known as galls, which can stunt the tree’s growth and reduce its ability to produce nuts. Chestnut blight is a fungal disease that causes cankers on the tree’s bark and can eventually kill the tree. Both diseases are spreading across Europe and pose a major threat to the health of sweet chestnut trees. 

Nicola Spence, UK Chief Plant Health Officer, said: “Sweet chestnut trees – like many other plant and tree species – are increasingly vulnerable to pests and diseases. Encouraging the public to be good plant health citizens and report disease sightings is absolutely crucial if we are to minimise the risk to our cherished treescapes.”

Ruth Chitty, RHS Plant Pathologist, added: “The Check a Sweet Chestnut project is a vital tool in the fight to protect tree health and empowers members of the public to get involved in conservation efforts. These pests and diseases pose a huge threat to Britain’s sweet chestnut trees, without which our landscapes would look very different, but by working together to record and monitor these trees we are helping safeguard them for future generations to enjoy.” 

The deadline to submit information for the project is during National Tree Week, which runs from 26 November – 4 December 2023.

Further actions you can take to improve plant heath are: 

  • Don’t bring plant material (plants, trees, fruit and seeds) into the UK from trips abroad. These might be carrying harmful pests and diseases 
  • Source plants from reputable nurseries and suppliers 
  • Clean boots, bikes and buggies before visiting woodlands and parks, to avoid spreading harmful organisms like fungi, bacteria and insects 

For more information and details of how to register your sweet chestnut tree please visit  


Notes to editors

For further information, images or interviews, contact Gina Miller [email protected] or the RHS Press Office at [email protected] / 0207 821 3080.

About the RHS

Since our formation in 1804, the RHS has grown into the UK’s leading gardening charity, touching the lives of millions of people. Perhaps the secret to our longevity is that we’ve never stood still. In the last decade alone we’ve taken on the largest hands-on project the RHS has ever tackled by opening the new RHS Garden Bridgewater in Salford, Greater Manchester, and invested in the science that underpins all our work by building RHS Hilltop – The Home of Gardening Science.

We have committed to being net positive for nature and people by 2030. We are also committed to being truly inclusive and to reflect all the communities of the UK.

Across our five RHS gardens we welcome more than three million visitors each year to enjoy over 34,000 different cultivated plants. Events such as the world famous RHS Chelsea Flower Show, other national shows, our schools and community work, and partnerships such as Britain in Bloom, all spread the shared joy of gardening to wide-reaching audiences.

Throughout it all we’ve held true to our charitable core – to encourage and improve the science, art and practice of horticulture –to share the love of gardening and the positive benefits it brings.

For more information visit

RHS Registered Charity No. 222879/SC038262

About Forest Research

Forest Research is Great Britain’s principal organisation for forestry and tree-related research and is internationally renowned for the provision of evidence and scientific services in support of sustainable forestry. @Forest_Research

Forest Research Tree Health Diagnostic and Advisory Service:

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The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.