Very interesting article. I copy pasted the pertinent points -
Black poplar is one of Britain and Ireland’s rarest trees.
The most recent survey (Cooper et al., 2002; Preston et
al., 2002) estimates that there are 7000 trees in England,
Wales and the Republic of Ireland of which 600 are
females. The majority of trees in England exist below the
line drawn from the Mersey to the Wash (Figure 3) and
there are areas, such as the Vale of Aylesbury, where the
tree is particularly frequent with 2400 specimens having
been recorded. The majority of pollarded trees are located
in the Welsh Borders and in East Anglia (Cooper et al.,
2002). Female trees occur throughout the distribution
range in England but are rare in Wales (Cooper et al., 2002).
There is considerable interest in the need to conserve the 7000 trees which are all that remain of the population of black
poplar growing in Britain. Recent work based on molecular techniques has provided markers which can unambiguously
distinguish first generation hybrids of P. x euramericana from P. nigra. This is an important tool as it enables non-hybrid
trees, which should be conserved, to be distinguished from exotic clones of hybrid poplars. Molecular markers have also
demonstrated that the British population of black poplar has low diversity, compared with that in other European
countries, and that there is a great deal of clonal duplication. Female clones are particularly rare. The ability to identify
clones offers the opportunity for conservation effort to be concentrated at the level of the clone rather than that of the
individual tree. Most of the British population is derived from ancestral material which colonised Britain after the last
glacial period from refugia in southeastern Europe.
Work aimed at understanding the physical processes which drive the ecology of floodplain forests may help to re-establish
populations of black poplar which have the capacity to reproduce and adapt to a changing environment.
Black poplar trees in Britain belong to the subspecies
betulifolia, otherwise known as the Atlantic race of
European black poplar. They differ from subspecies nigra
in that their young expanding leaves have hairy petioles.
Black poplar used to grow in the natural floodplain
forests which lined the banks of rivers in Europe,
however, much of this habitat has been lost since the 17th
century through such processes as urbanisation, land
drainage and canalisation of rivers. Recently there has
231 Corstorphine Road
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EH12 7AT
Forestry Commission GB
been interest in the re-establishment of floodplain
habitats, including the floodplain woodlands which
contain black poplar as a key species.
Due to Europe-wide concern over the increased frequency
of river flooding, consideration is now being given to the
development of natural flood defences. The Natura 2000
network of nature conservation sites across Europe
includes many which are located on floodplains. Although
there is very little floodplain woodland in the UK today,
this may begin to change with the increased recognition
that such woodlands:
• have a potentially high amenity value;
• can perform a commercial forestry function;
• have the potential to help in flood management;
• help the control of diffuse pollution of water.
A number of projects and initiatives across Europe are
looking at the value of floodplain forests. Of particular
interest, in relation to black poplar, are the EU funded
FLOBAR 1 & 2 projects that are investigating how to
restore the biological function of floodplain forests by
restoring the physical processes that drive them.