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Contact Details

• Parks & Open Spaces
  London Borough of Bexley
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  Bexleyheath
  Kent DA6 7LB
• 020 8303 7777

Biodiversity in Bexley

About Bexley's wildlife

Bexley's Biodiversity Action Plan

Species Action Plans

Black oplar - (Populus nigra)

Aims

• To protect existing trees and develop a diverse age structure through planned planting.
• To inform and educate landowners, managers and the public about black poplars.
• To ascertain, maintain and increase the genetic diversity.

Introduction

• A tree of up to 35m height, the black poplar has nearly black, deeply fissured bark and branches arching downwards and forming a wide crown. It is a plant of wet woodlands and stream-sides. Red male and green female catkins are borne on separate trees.
• The wood of the black poplar is naturally heat and fire resistant and was used for brake blocks on wagons in days of yore. The Atlantic form (subspecies betulifolia) is found in Britain, Ireland, Northern France and parts of Western Germany.

Artist: Barry Small; © London Borough of Bexley

1. Current Status

1.1 Status Nationally

• At the northern extreme of its range, most trees in Britain are found south of a line from the Mersey to the Humber estuaries. There are thought to be few individual clones. Caution is needed over determining what are native as opposed to planted trees and over the frequent hybridisation with other poplar species. The Black Italian Poplar, "Populus canadensis", is planted more commonly.
• The tree is nationally rare in its native habitat. Apart from recently planted cuttings, most black poplars are thought to be more than 100 years old.

1.2 Status in Bexley

• Numbers of the species in London are unknown and are to be the subject of further investigation. Twenty-one Boroughs have records of the Black Poplar, including Bexley, Greenwich, Bromley and Croydon, as well as Boroughs on the north bank of the River Thames to the north of London.
• In Bexley a female tree is flourishing in the vicinity of Foots Cray Meadows, of importance as female trees are thought to represent only some 5% of the known native population. Nearby, a clump of Black Poplars appears to be growing from a felled stump.

2. Current factors causing loss or decline

• Drainage and drier summers can cause stress to established trees and affect the ability of seeds and seedlings to survive.
• Unsympathetic river bank and ditch management can result in a lack of wet mud banks and possibilities for regeneration from fallen trees or branches and seed germination and growth are limited.
• Tidying up fallen trees and branches prevents regeneration.
• Cross-pollination means that it is unlikely that pure black poplar seed is produced under uncontrolled pollination in the wild.
• Planting from clones ensures purity if taken from properly accredited sources but leads to lack of genetic diversity.
• Pollarding or re-pollarding can damage or even kill trees over a period of several years after the action is taken.

3. Current action

3.1 Legal Status

• Black Poplars are protected by the Wildlife and Countryside Act 1981 and may not be uprooted without the permission of the landowner.
• Felling may be prevented by tree protection orders.

3.2 National Action

• A National Black Poplar Working Group was formed in the early 1990s with English Nature taking the lead on an Action Plan for the Black Poplar. The London Biodiversity Partnership has identified objectives, actions and targets in draft.

3.3 Local Action

• Propagate by cuttings from verified stock.
• Plant out in areas able to meet water requirements such as Foots Cray Meadows.

4. Advisory

• London Biodiversity Partnership objectives include location and safeguarding of London's Black Poplars and increasing their number and genetic variation.
• Bexley Action Plans and objectives should support the London-wide programme in pursuing these objectives.
• Clone banks have been established at various points in London and the Home Counties.
• Genetic research is currently being undertaken at the Universities of Nottingham and Edinburgh.
• Re-pollarding appears to be damaging or even killing a number of trees, often several years after it has taken place.

5. Links with other Bexley habitat and species Action Plans

• Wetlands
• Woodland
• Parks and open spaces
• Private gardens

6. Links with other local and national policies

• London Biodiversity Action Plan, Vol 2, Black Poplar Species Action Plan.

7. Table of objectives and actions

Objective 1: To ensure protection of existing stock of black poplars in the Borough through appropriate management prescriptions and tree preservation orders.

Target: Locate, monitor and have in place management prescriptions for all the Borough's black poplars by 2004.

Objective 2: To identify available sites for planting and increase the stock of poplars.

Target: Establish a population of 50 new black poplars within the Borough by 2005.

Public involvement for black poplar

• Black poplar should never be planted near houses, on golf courses, by bowling greens, or around fields on heavy land: its water demands may well cause shrinkage and searching rootlets will completely block drains.
• To find the height of a specimen all you need is a straight stick the same length as the distance from your eye to the tip of your outstretched arm. Hold the stick upright at arms length and move forwards or backwards until the stick coincides with the tree. The distance from you to the base of the tree is the same as the height of the tree.

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