5 Native Black poplar

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					5. Native Black poplar




                   Photograph: Native Black Poplar, Islington


1. Aim

   •   To protect and enhance the existing native black poplar trees in the
       borough.

   •   To raise awareness and increase knowledge of the black poplar

2. Introduction
The native black poplar (Populus nigra ssp. betulifolia) is a huge tree. It can
be up to 30 metres high, with a 20 metre wide canopy, and has low sweeping
branches and a pronounced lean. The leaf is triangular shaped, longer than it
is wide, with blunt teeth.

The tree was a distinctive feature of lowland river valleys but for a variety of
reasons it is now scarce and the remaining populations are scattered. As a
result the black poplar is the most endangered native timber tree in Britain.

It is predominately a tree of open ground, not woodland, and will not tolerate
side shade. The favoured habitat of the black poplar is wet woodlands and it
is often found along riverbanks. Since 1850 virtually no native black poplars
have been planted (until quite recently), particularly as they have been
superseded by the faster growing hybrids. Consequently, most mature trees
are old and dying, and if nothing is done we will lose them altogether.

This is why the native black poplar is included in Biodiversity Action Plans for
many areas around the country. Black poplars have separate male and
female trees (dioecious), and a viable population needs trees of both sexes


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growing fairly close to each other. Historically, female black poplar trees have
been systematically removed as they produce large amounts of seed fluff in
the spring. Consequently the female tree is now very rare.

3. Current Status
There are an estimated 7,000 native black poplars in Britain. Many of these
are believed to be genetic clones so there are probably considerably less
distinct genotypes.

The tree has strongholds in Shropshire, Cheshire, the Vale of Aylesbury and
Suffolk. The vast majority of the trees have reached maturity and there has
been very little planting of new trees until quite recently. Female trees are
particularly rare, with an estimated 400 nationally. Suitable conditions for
germination of seed are no longer present in Britain.

4. Specific Factors Affecting the Species

•   Loss of both natural river systems and unstable floodplain sediments
    results in an absence of suitable habitat for natural regeneration.
•   The lack of native male trees in close proximity to native females means
    that there is very little opportunity for fertilisation.
•   The presence of large numbers of hybrid trees means that seed from
    female trees is very likely to be hybridised, resulting in seed of doubtful
    provenance.
•   As many trees are in poor condition, mortality rates are high due to natural
    factors such as old age, drought and windthrow, especially as trees are
    often large isolated specimens.
•   Removal of fallen trees which would otherwise survive in situ or
    regenerate from the stump.
•   The widely dispersed population makes site based conservation more
    difficult. Widely available and commercially preferable hybrids have been
    planted in preference to native stock for the last 150 years.
•   Low genetic variation. Most of the individuals remaining in the country
    have been propagated largely as cuttings from around 600 individuals.
•   Lack of female trees. The individuals selected for propagation were
    primarily male. The reason for this was merely for aesthetic purposes.
•   The decline in the demand for timber and wood products from the native
    Black Poplar.
•   The removal of hedgerows and the trees which grow in them.
•   Loss of appropriate habitat for germination as a result of drainage, river
    engineering schemes and agricultural improvement.
•   Possible damage to remaining trees through agricultural operations on
    adjacent land, e.g. ploughing close to the trees.
•   Building development, for example a tree at Quorn was felled in 1990 to
    make way for new housing.
•   Hybridisation with non-native poplars




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Without active conservation the black poplar will soon become extinct in the
country.

5. Current Action

5.1 Legal Status
Black poplars receive protection under the Countryside and Wildlife Act, 1981,
as other wild plants in the UK. Tree Preservation orders and the 1967
Forestry Act may prevent the felling of trees.

5.2 National Action
There is a London Species Action Plan for the Black Poplar, which was
produced by the London Biodiversity Partnership.

The UK Black Poplar Conservation Group (UKCG) exists to with the aim of
bringing practitioners to share ideas.

5.3 Local Action
Three native black poplars have been discovered in Islington and are the only
ones known about so far. The boroughs tree officers are now monitoring
them.

6. Objectives, Actions and Targets

Objective 1
To protect and retain all remaining native black poplar trees -Populous nigra
var. betulifolia in Islington.

Target
Safeguard all existing native black poplars in Islington

Action                                              Target               Other
                                                              Lead
                                                     Date               Partners

To create a register of all known black poplar
                                                     2010      LBI       UKCG
trees - Populous nigra var. betulifolia in
Islington.
To report locations of all known Black Poplar
trees -Populous nigra var. betulifolia in
Islington to the planning department, so that        2010      LBI       UKCG
they can create tree preservation orders.


To liaise with the London Tree Officer
                                                     2010      LBI       UKCG
Association with reference to any citywide or
nationwide black poplar tree -Populous nigra


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var. betulifolia database.


To investigate the possibilities of planting
more black poplar trees -Populous nigra var.
betulifolia in suitable locations. New trees       2010     LBI       UKCG
should be propagated from cuttings taken
from local stock.

Objective 2
Raise awareness of the native black poplar in Islington

Target
Provide information for landowners and general public

Action                                         Target              Other
                                                          Lead
                                                Date              Partners

To contact relevant landowners and inform
them of the value of native black poplar        2007      LBI      UKCG
trees, and the reasons for their retention.


To increase public awareness of the current
situation regarding black poplar trees -
                                                2007      LBI      UKCG
Populous nigra var. betulifolia and the
importance of retaining existing trees.


To investigate the possibility of creating a
leaflet to highlight the importance of the
species, techniques for conservation,           2007      LBI      UKCG
propagation and planting and to aid the
public, tree wardens, rangers etc. in
recognizing the species.


Links with relevant Habitat Action Plans

Habitats
Parks and Openspaces

Abbreviations
LBI           London Borough of Islington
UKCG          UK Black Poplar Conservation Group




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Description: 5 Native Black poplar