Britain’s rarest native tree takes root in Devon
The National Trust is creating a ‘living library’ of trees in East Devon in efforts to help save Britain’s rarest and most threatened native species: the black poplar.
The charity is even offering ‘adopt a plot’ schemes to help the conservation effort.
Building on existing efforts up and down the country and with thanks to support from HSBC UK, the conservation charity is forming a living gene bank of black poplar at Killerton, near Exeter, to help save the declining species.
Once as common as oak and beech, drainage of land and demand for faster and straighter growing non-native timber trees has contributed to the gradual decline of the species.
Experts say the population is now so fragmented that black poplar has effectively died out in the wild.
Out of an estimated 7,000 black poplar trees left growing wild in Britain, there are only around 150 that have been tested are genetically unique.
Many of the trees are male as their aesthetics meant they were historically favoured over the female trees. They cannot reproduce alone.
Experts say there’s an urgent need to form a breeding population of male and female trees to maximise the gene pool – and make the species resilient again.
Working in partnership with Forest Research and other community groups to locate and collect a diverse selection of cuttings, rangers at the conservation charity have now planted a total of 80 distinct clones at the Devon site.
Over the winter months, 27 rooted cuttings of the wetland-loving tree have been planted out.
They have been added to the growing collection already taking root along the nearly two mile stretch of newly restored floodplain at the River Culm floodplain.
‘The floodplain: the tree’s favoured habitat’
‘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,’ says Fi Hailstone, National Trust ecologist at Killerton.
‘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.’
Initially, Killerton received 43 trees from arborist Jamie Simpson, who works on a similar conservation project in the Borough of Richmond.
They were grown from cuttings from the last wild population of native black poplars situated near the Thames footpath in London.
Further cuttings were collected via the Black Poplar Group which includes the National Trust, Forest Research, The Otter Trust, The Tree Council, Chester Zoo, Suffolk Tree Wardens and groups in Herefordshire and Dorset.
‘An iconic tree in the British landscape’
‘The native black poplar is an iconic tree in the British landscape; arguably our tallest native broadleaf, it features famously in John Constable’s landscape The Hay Wain,’ says Tom Shuttleworth, Tree and Woodland Advisor for the National Trust.
‘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.’
At the National Trust’s Plant Conservation Centre in Devon propagation of new native black poplars is already underway and will be expanded using cuttings from the trees at Killerton once they have established.
The propagation of the under-threat trees was kickstarted by donated cuttings from Forest Research who carry out DNA fingerprinting of black poplar, checking to see if they’re native, which clone they originate from and if they can be used in the race to create the future generation of the species.
‘The DNA fingerprinting of black poplars has been very useful in identifying the large-scale clonal (clone) duplication that has taken place with some clones but also highlighting the rarer individuals still in existence,’ explains Stuart A’Hara at Forest Research.
‘The clonal collection at Killerton is a testament to all the good work carried out by the various conservation groups over the years with black poplar at the heart of their work. It will be a tremendous resource going forward.’
Further initiatives to halt the decline of the black poplar are happening across the National Trust including the establishment of 16 trees in restored wood pasture on the Oxburgh Estate in Norfolk.
The newly restored River Culm floodplain at Killerton, Devon, where a population of rare black poplar is being established. Image: © John Herbert / National Trust Images.
Killerton: one of six ‘nature super sites’
At Quarry Bank rangers have also been working in partnership with Chester Zoo, who run a breeding programme to produce new black poplar clones, to plant trees out on the Cheshire estate.
Killerton is one of six nature super sites identified by the National Trust for their potential to restore nature across whole landscapes through activities such as planting trees and restoring rivers.
