Saving our native Black Poplars
With only 7,000 Black Poplars left in the UK, a pioneering tree planting project at Quarry Bank, will look to restore the fortunes of this important native tree. National specialist for plant conservation, Simon Toomer, looks at the history of this scruffy native tree.
The British Isles is not well furnished with native tree species. Periods of glaciation and the early formation of the English Channel around 10,000 years ago thwarted the northward migration of species from the ice-free refuges further south. Nevertheless, our 30 truly native trees have played an important part in our economic and cultural history with a wealth of associations and traditions.
Overtaken by the modern world
Most people can easily name the common and widespread species like oak, ash and beech but alongside these are more elusive or difficult to identify species with restricted distributions. One of the rarest of our trees is the black poplar (Populus nigra ssp. betulifolia), an inhabitant of floodplains and wet ditches and once a common sight in the countryside. John Constable’s familiar painting The Hay Wain of 1821 shows black poplar trees growing alongside a meandering river.
Drainage for agriculture certainly contributed to its gradual decline but, probably more significant, has been its loss of black poplar’s reputation as a versatile provider of timber for a wide range of construction, domestic and agricultural uses. Matches, floorboards, carts, and many other everyday objects were commonly made of black poplar wood and when the Mary Rose was raised in 1982 an arsenal of black poplar arrows was discovered onboard. Modern timber requirements favour faster- and straighter-growing species or hybrids selected for these qualities and there are now reckoned to be only around 7000 trees left in the UK.
A key for biodiversity
Despite its close relationship to its European cousins like the ornamentally-shaped Lombardy poplar (Populus nigra ‘Italica’), the black poplar has a more wild and unkempt profile more reminiscent of a bad hair day than a classical column. Its loss from our landscapes would also impoverish our landscape and arboricultural history. It would also represent a further depletion of our tree biodiversity and the creatures that rely on it for their survival.
Fortunately, new poplar trees can be propagated from long cuttings known as truncheons. This technique utilises the ability of most members of the willow family to sucker from roots or shoot from cut limbs to produce cloned offspring of the parents. This is a common strategy of trees growing in waterlogged areas where reproduction through seed may be less viable. Another distinctive family feature relates to sex: botanists describe poplars as dioecious meaning that individual trees (and their offspring) produce either male or female flowers – but not both. There are thought to be only about 700 females in the UK (10 per cent of the total Black Poplar population), perhaps a consequence of the tradition of propagating replacements from male trees.
Returning Black Poplars to Quarry Bank
Many initiatives have been launched by conservation bodies at national and county levels in response to the decline of black poplar and the National Trust is helping to give the species a secure future through distribution and planting more widely. A number of National Trust properties have trees growing in natural and cultivated settings. At Westbury Court in Gloucestershire, several mature black poplars can be seen adding to the atmosphere of the Dutch-style water garden.
At Quarry Bank in Cheshire Trust rangers have been working in partnership with Chester Zoo who run a breading programme to produce 100% genetic Black Poplar clones. Quarry Bank sits relatively in the middle of the River Bollin catchment which was once a strong hold for Black Poplars due to large areas of flood plains and wet woodland that dominated the catchment, intensive agriculture and development drained the land which lead to the decline of the species through the catchment. Quarry Bank is perfectly situated to start the spread of the Black Poplar back through the Bollin Catchment. The rangers have planted 24 (12 male and 12 female) of the pure Black Poplars across the estate in strategic locations, in pairs, to maximise chances of reproduction. We aim to plant over 100 Black Poplars across the estate over the next 2 to 3 years. The rangers have also been in talks with landowners up and down the River Bollin catchment about planting Black Poplars, all of which are really supportive and excited by the prospect of having Black Poplars on their land.