Survival of rare poplar hinges on tree 'zoo'

THE MOST endangered native British timber tree has been identified, writes David Nicholson-Lord. It is the black poplar, popular among wagon makers in the days of Constable but now neglected and misunderstood. Of the estimated two billion trees in Britain, there are probably only 1,000 left.

To preserve its genes for the future - the tree displays a resistance to bacterial canker which could prove valuable for cross- breeding - an arboreal 'zoo' is being established in Norfolk. Fifty saplings will be planted on an estate near Downham Market, grown from poplars at least 150 years old and forming the basis of a genetic bank for new planting.

John White, a research dendrologist at the Forestry Commission's Westonbirt arboretum, yesterday described the black poplar - Populus nigra betulifolia - as a 'forgotten tree'. In the 18th century, it was a familiar part of the lowland English landscape, favoured by wagoners - its soft wood helped absorb impact - and builders of maltings and oast houses.

Planting 'water poplars' for profit was recommended from ancient times. Medieval scaffolding poles were cut from pollards. Victorian clothes pegs came from poplar shoots. The wood has good fire resistance and was widely used for bowls.

Two centuries ago, the black poplar was 'as ubiquitous as the oak' in areas like East Anglia, Mr White said. It forms the backdrop to many Constable paintings, not least The Hay Wain - which was probably itself made of black poplar.

However, the tree has lost much of its wetland habitat. Its population has become sexually imbalanced: to avoid 'nuisance' from female seed fluff, mainly male trees have been planted. It has been confused with other poplars, repeatedly hybridised and even misidentified as an introduced species.

It was rescued by botanist Edgar Milne-Redhead, whose survey published in 1990 showed that little planting had taken place since 1850, when a foreign hybrid replaced it in popularity, and that most trees identified as black poplars were hybrids.

Mr White added: 'Without that work, we would have lost the tree by now. It would have gradually faded away - a case of extinction by default.'

(Photograph omitted)