Priority Species: Black Poplar
1. Establish an understanding of the distribution and status of black poplar and raise awareness of its status
2. Maintain existing populations of black poplar by reducing fragmentation and loss of individuals
3. Increase numbers of black poplar through planting of native stock in suitable habitat, including through habitat creation schemes.
Vision Statement: For increased populations of native black poplar of both sexes in appropriate floodplain locations, sufficient to regenerate naturally.
|1. To expand the population of recorded native black poplar in the Durham BAP area.||individuals||individuals||50|
The black poplar is a tree of wet woodland and stream sides, particularly in the floodplains of lowland rivers. It is now the UK’s most endangered and rarest native timber tree and has declined close to extinction with less than 3000 individuals remaining. Most of these are nearing the end of their natural lifespan and will be lost in the next few years.
The native tree was widely cultivated for timber up until the mid 19th century, when new, more productive hybrid strains of poplar were introduced from abroad. Today the majority of planted poplars are of European P. nigra stock or are hybrid poplars with only some P. nigra ancestry, such as the popular Black Italian Poplar (Populus x euramericana Serotina).
Modern changes to the landscape, including drainage over the last forty years and the management of rivers and riverbanks has led to the disappearance of this tree’s natural habitat. Today only a few trees still occur alongside rivers or stream; most occur as planted trees by ditches and ponds or in hedgerows, and occasionally planted in urban areas.
The majority of surviving trees occur in lowlands to the south of the Humber and Mersey estuaries, particularly in the west Midlands, Welsh marches and East Anglia, with scattered individuals occurring as far north as the River Tees.
Durham has some of the northernmost records for the native black poplar, but only a small number of individuals are known to occur.
The current state of the black poplar in the Durham area is still not well known, and is based on a handful of records in the Durham Flora and reports made to Darlington Borough Council. Further work has been done in the Tees Valley and North Yorkshire and several trees have been recorded. The widespread black Italian poplar, a poplar that has been frequently planted in woodland, copses, shelter-belts and along roads and hedgerows in central and eastern Durham has often been recorded in error for the true black poplar as well as manchester poplar and hybrids of white poplar.
Records of black poplar dating over the last 20 years are almost entirely from the Darlington area. These include a tree in a hedgerow at Whessoe, a couple of single trees along the side of Baydale Beck and near Whessoe Holme and an avenue of trees at Middleton-St. George (these most certainly appear to have been planted as cuttings). There is also a record of a single tree at Craghead (Derwentside) in a garden.
- Black Poplar scab appears to be a serious threat to native black poplar, threatening to wipe out native populations in Cheshire. There has also been one report in Newton Aycliffe.
- The majority of trees are at the end of their life, since there has been no new planting of natives since the introduction of hybrid varieties in the 19th century.
- Genetic isolation. Genetic analysis of surviving trees suggests that the majority are extremely closely related, due to a long history of vegetative reproduction.
- Poor natural regeneration. Few remaining black poplars are in their ideal habitat and this makes it difficult for them to reproduce successfully. Regeneration from seed requires bare wet ground in June, and seedlings need moist ground through to autumn. Both flooding and drought are fatal to the seedlings and they are unable to develop in competition with other vegetation.
- Shortage of female trees. Male trees were preferentially planted over female trees, since the latter produce copious amounts of fluffy seed. This exacerbates problems of genetic isolation and regeneration.
- Loss of suitable habitat for the native black poplar through agricultural improvement, riverbank development and canalisation of rivers has resulted in fewer suitable places for successful natural regeneration of surviving poplars to occur.
- Difficulties in distinguishing native from introduced black poplars may lead to under or over recording of the native species. Reintroductions based on false identification will lead to non-native trees being propagated