Disease-resilient trees improve butterfly habitats

White-letter Hairstreak butterflies are reliant on mature, flowering-age elms

An estate in Kent is planting young elm trees bred to be resilient to Dutch elm disease (DED) in a bid to help improve habitats for a rare species of butterfly.

The Hadlow Estate near Tonbridge planted the 30 young elm trees as part of the Elm Heritage Kent project, which planted more than 94,000 native-species trees in four years.

DED is a fungal infection spread by tiny bark beetles that can rapidly wither and kill healthy trees, which has an impact on rare species including the White-letter Hairstreak butterfly.

The species is reliant on mature, flowering-age elms for caterpillar food and breeding habitats.

Dr Roland Brown, chair of Butterfly Conservation's Kent and South East London branch, said White-letter Hairstreaks only had a dispersal range of about 1km (0.6 miles) to find new habitats.

"This makes them very vulnerable to becoming isolated and if their local elms are wiped out by disease, or growing climate pressures like drought, their chance of survival is very slim," he explained.

Kate Teacher works at The Hadlow Estate

In 2024, the project partnered with the Kent and South East London branch of Butterfly Conservation and Natural England's East Kent Downs Farmer Group to identify areas with existing records of White-letter Hairstreak butterflies and elm trees.

Project officer Katherine Meade said: "Using this data, we were able to strategically plant more DED-resistant cultivars, benefiting existing butterfly populations by creating corridors and stepping stones of elm habitat between existing mature tree locations."

Dutch elm disease first made its appearance in the UK in the 1920s, killing up to 40% of all elm trees.

A more aggressive strain later emerged in Britain and more than 25 million trees died or were felled during the 1960s and 1970s due to the disease.

Kate Teacher, from The Hadlow Estate, told BBC Radio Kent: "Elms were such a familiar and much loved sight across the Kent countryside so it's brilliant to be part of a initiative from KCC to try and re-establish these beautiful trees and support wildlife."