Britain’s rarest native tree takes root at Killerton

Efforts are being stepped up to save Britain’s rarest and most threatened native species of tree.

The National Trust is creating a “living library” gene bank of trees in east Devon to help protect the black poplar.

The black poplar was once as common as oak and beech, but the drainage of land and the demand for faster and straighter growing non-native timber trees has contributed to the gradual decline of the species.

Out of an estimated 7,000 black poplar trees left growing wild in Britain, only around 150 of those that have been tested are genetically unique.

Many are also male, as historically they were favoured aesthetically over the female trees which produce large amounts of white fluffy seed in spring.

Unable to reproduce alone, an urgent effort is needed to form a breeding population of male and female trees to maximise the gene pool and make the species resilient again.

The National Trust has now planted a total of 80 distinct clones at the Killerton estate, near Exeter, which makes it the most diverse population of the species in the country.

Fi Hailstone, National Trust ecologist at Killerton, said: “We want to establish a naturally reproducing population of black poplar on the stretch of river we have relinked to the floodplain, the tree’s favoured habitat.

“Black poplars need male and female trees within 200m of each other to pollinate each other.

“With numbers in huge decline this is not something likely to happen in the wild which is why we are stepping in to create a new breeding population.

“The trees can live for over 200 years and can grow to 30 metres in height.

Once established, cuttings can be taken from the trees and spread to planting projects elsewhere, acting as a living gene bank, bolstering the resilience of the declining species’ and boosting its chances of survival.”

Tom Shuttleworth, tree and woodland adviser for the National Trust, added: “The native black poplar is an iconic tree in the British landscape.

“It is arguably our tallest native broadleaf and it features famously in John Constable’s landscape The Hay Wain.

“Slower growing than hybrids and American poplars, it was a useful timber tree, its wood being strong under flex and temperature and used for cartwheels, brakes, and in mantle pieces.

“It has important biodiversity value to numerous species including the poplar hawk moth, hornets, figure of eight moths and aphids, which in turn support wood ant species.”