RHS calls on public to help map sweet chestnut trees

The Royal Horticultural Society (RHS) and Coventry University are calling on the public to help spot sweet chestnuts on their daily stroll as they have launched a new citizen science project to help protect this at-risk tree.

The iconic sweet chestnut (Castanea sativa) is an important source of food for wildlife – including bees, pollinators and squirrels - and can live for up to 700 years when healthy.

Thought to have been originally introduced by the Romans, the trees are now under threat from the newly arrived oriental chestnut gall wasp (Dryocosmus kuriphilus) which disfigure and weaken the tree, with the RHS Science team eager to map the non-native insect and trees in varying states of health.

Facts from the RHS:

1. Most sweet chestnut trees can be found in the south of England, particularly in Kent and Surrey.
2. The oriental chestnut gall wasp was first discovered in the UK in 2015.
3. The wasp larvae cause abnormal growths, known as galls.
4. In high numbers galls can weaken the host tree, making it more vulnerable, in particular to sweet chestnut blight.

To take part in the Check-a-Sweet Chestnut Survey, members of the public can register on the RHS website and log their findings online via the TreeZilla and TreeAlert reporting tools.

RHS Plant Pathologist Jassy Drakulic says: “Organisms that arrive from abroad and attack trees are on the rise, with an average of six new species arriving in Europe each year. Citizens as a collective can gather huge amounts of data that would never be possible with official inspections and surveys.

We hope that by finding and measuring sweet chestnut trees this will breathe new life into the trails many people will have often walked in lockdown, and that the project will inspire people to appreciate and learn more about the trees in their area.”