Three sub-species with a broadly geographical as well as morphological basis are recognised in Europe, largely discriminated on the nature and extent of their hairiness, there is however considerable overlap. The western European subsp. betulifolia (Pursh.) W. Wettst. has somewhat pubescent twigs and young leaves, it is the native form found in the British Isles, although the extent to which its current distribution can be considered natural and its status in many areas is questionable (see distribution). Glabrous plants indistinguishable from the more Central and Eastern European subsp. nigra are also to be found in apparently natural situations in the British Isles. Subsp. caudina (Ten.) Bug. , with more hispid foliage and twigs, occurs in the Mediterranean region (North Africa, Spain, Southern Italy, the Balkans, eastwards to Iran).Numerous growth-forms have been selected and have been variously taxonomically treated, from species to cultivar level. Historically the most frequently planted is the fastigiate male clone Cv. ‘Italica’ – the Lombardy Poplar, introduced from N. Italy about 1758. A particular clone of subsp. betulifolia grown around Greater Manchester and widely distributed from there is known as the Manchester Poplar – while pollution tolerant it has recently proven to be highly susceptible to Poplar Scab (see Diseases). Recent plantings have tended to be of cultivars derived through hybridisation with North American species, such as P. deltoides and their backcrosses with different forms of the parental taxa. This has made identification and discrimination of “native” Black Poplars particularly challenging.

Genetics
Populus nigra is a diploid with 2n=38 chromosomes. As one of 3 species included within the European Forest Genetic Resources Programme (EUFORGEN) a considerable amount of data has accrued as to the levels and distribution of genetic diversity within this species across Europe (Cottrell et al., 2005), this has recently been supplemented by local initiatives driven by LBAP’s which hopefully will provide a detailed picture across the British Isles (Adams, 2009). The species shows rather low genetic diversity across its wide range but the greatest levels are present south of the Pyrenees, Alps and Balkans indicating that these were refugial areas during the last glaciation and recolonisation of Northern Europe has been accomplished by relatively few clones, naturally and later with human assistance. Probably less than 100 clones exist in the British Isles, within Greater London 6 of the previously identified clones are known to exist in multiple locations, the most extensive being the Manchester Poplar clone. New clones are still being discovered as more intensive sampling is being made; recent work has shown another 9 clones to be present in Greater London, generally as single individuals, on the Thames bank in Kew, Syon Park and at Barnes, where they are threatened by planned renovation work.

Populus nigra the black or water poplar is Britain’s rarest native timber tree found alongside waterways in the UK.The black poplar is also found in Southern, Central and East Europe, North Africa and eastwards to Central Asia the Black or Water Poplar is almost certainly native to lowland England.Black poplar trees can live for over 250 years and there are historical records of trees approaching 300 years of age (White, 1993). A virulent disease Poplar scab has hit Populus nigra and generally takes around 3 years to kill a tree. The infection is caused by a fungal disease called Venturia populina, or its asexual stage Pollaccia elegans. A shortage of male trees and a changes in conditions necessary for germination and early establishment have also made natural sexual regeneration is extremely uncommon.Nationally is no special legislation to protect this species. The concerns over increasing threats and ongoing decline mean however that many local Biodiversity Action Plans have now adopted this species for targeted conservation.

This deciduous tree produces catkins in March and April, before the first leaves appear, and is pollinated by the wind (1). The fruits are green capsules that open up to reveal the very small seeds that have wispy hairs attached (3), which aid their dispersal in the wind (6). In order for this tree to regenerate, male and female trees must be fairly close together, and fertilised seeds must fall on bare soil that is still moist in June (8). The timber, which is springy and light, is highly resistant to fire, and has been used for a variety of purposes, including floorboards, clogs and arrows that were found on the Elizabethan galleon, the Mary Rose (8).

Black poplar, thought to be Britain's most endangered native timber tree (2), has a wide, rounded crown and dark grey fissured bark, with many swellings ('bosses') on the trunk (1). The deep green leaves are roughly triangular or oval in shape and become yellow in autumn (3). The flowers occur on 3-5cm long catkins (1), and male and female flowers are produced on separate trees; male flowers have red anthers and female flowers have green stigmas (1). Old specimens often develop an obvious lean (8), and older branches are frequently pendulous (9).

Black poplar trees are robust dioecious tree to 35m tall (usually less) with a wide (c.20m diameter) rounded crown.

• Branches
  • stout
  • arching often down-curving
  • upswept at the tips
• Trunk
  • conspicuously bossed
  • often inclined
  • deeply furrowed dark-grey bark
  • diameter at breast height up to 250cm
• Twigs
  • glabrous to finely pubescent
  • terete, yellowish-brown at first, becoming grey-brown
  • sticky with resin
  • buds c.10mm, narrowly ovoid, acuminate, shiny, dark brown
• Leaves
  • 5 -10 x 4-8cm, rhombic-ovate to trullate
  • long acuminate
  • minutely crenate-serrate
  • with obvious translucent margin
  • broadly cuneate to truncate at base
  • larger on sucker and coppice shoots
  • on short shoots smaller, broader and more deltate,
  • dark green above, paler beneath,
  • initially bronze-tinted and
  • with a distinct aroma
  • becoming rather leathery in texture
  • without basal glands
  • petiole 3-7cm
  • pubescent when young, glabrous later
  • laterally compressed
  • often conspicuously galled

Flowers

• appearing before the leaves in March-April;
• catkins 3-5 x 0.6-0.7 cm
• female
  • grows to 15cm in fruit
  • pendent
  • each flower with a cup-like disc
  • subtended by oblong
  • deeply laciniate scales,
  • membranous,
  • greenish or brownish
  • soon deciduous
• male
  • 12-15(-20)cm stamens
  • purplish crimson anthers
• female
  • 2 deeply bifid greenish stigmas
  • ovary sub-globose, glabrous
• Capsule
  • 2-4 valved
  • seed minute
  • white-fluffy
  • numerous but rarely forming in the British Isles
  • usually then the result of pollination by other Populus taxa

Trees can live for over 250 years and there are historical records of extant trees approaching 300 years of age (White, 1993). Some trees are however certainly older, the original having fallen and a new trunk, or trunks developing from this. Outside of recent conservation programmes there have been few new plantings in the last 100 years and virtually no natural regeneration; the British Water Poplar population is thus aging and facing an uncertain future almost certainly dependant on conservation activities for its sustenance.

Reproduction
The species is dioecious and over much of the extant British range there is a considerable disparity between the numbers of male (frequent) and female (rare) trees, a consequence of the deliberate selection of male clones (they do not cause problems through the production of debris associated with flowering/fruiting); in some parts of lowland England (eg. Sussex) ratios approaching 1:1 are still found but tree numbers are low and the sexes are not intimately associated. Natural sexual regeneration is thus extremely uncommon, not least because the conditions necessary for germination and early establishment are rarely present. The seeds are short-lived and must fall on bare, moist competition-free surfaces that are neither dry, or become flooded. Where conditions do allow germination, seedlings are likely to be hybrids as pollen contamination from the more abundant cultivated varieties is probable. The estimated radius for pollen travel is about 16km (Jones, 2004).Although the tree doesn’t sucker readily, natural vegetative propagation from layering of fallen individuals, debris washed down rivers, etc. occurs, but is less likely to happen now that watercourses are so managed and river and floodplain systems have become less dynamic. Damage to root systems through agricultural and other activities may encourage suckering.Water Poplar can be propagated from hardwood or softwood cuttings, the latter more easily. Early advice suggested using lengths of 15-20cm, from new growth made in the proceeding summer, taken while the tree is dormant; vigorous epicormic shoots are particularly suited to this purpose. These cuttings were then planted such that at least half their length was underground. Recently the use of longer truncheons, 1-2m lengths of vigorous vertical terminal shoot growth, trimmed at the base and rapidly planted to at least a depth of 30cm is recommended. Past bunch planting of cut shoots has given rise to dense clonal stands in some localities.

Populus nigra var. italica Du Roi:
Bolivia (South America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Populus nigra var. italica Koehne:
Bolivia (South America)
China (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Populus italica Moench:
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

Populus nigra L.:
Canada (North America)
Pakistan (Asia)
United States (North America)
China (Asia)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

A widespread species; distribution includes Europe and Central Asia. The list of countries of occurrence is incomplete.

Canada

Origin: Exotic

Regularity: Regularly occurring

Currently: Unknown/Undetermined

Confidence: Confident

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

The native subspecies of black poplar, Populus nigra betnifolia, is locally frequent in parts of lowland England and Wales, rarer in the north of England and Scotland, and rare in Ireland (9)(10), and also occurs in western Europe. At present the British population numbers just 2000 to 3000 trees (2). Elsewhere, black poplar is widely distributed but increasingly scarce throughout much of Europe reaching into central Asia and North Africa. It is generally absent from the far north of Europe (4).

Tree, up to 35 m tall,bark dull gray. Buds sticky. Young shoot terete, glabrous. Leaves on long shoots larger, broadly deltoid to deltoid, usually broader than long, truncate or rounded at the base, crenate, acute to acuminate. Leaves on short shoot smaller, rhombic ovate, longer than broad, cuneate at base, crenate-serrate, acuminate. Peiole 2.5-6 cm long, glabrous, lamina 5-10 (-12) x 4-8 (-15) cm. Male catkin 5-7.5 cm long; bracts brownish, 3-4 mm. Stamens (6)-15-30, anthers purple. Female catkin 5-10.5 cm. Ovary glabrous, stigmas 2, sessile, broad, obcordate. Fruiting catkin (5)-10-16 cm long. Capsule shortly stipitate, 2-valved, 5-7 x 3-4 mm.

Trees to 30 m tall; bark dull gray, furrowed when older; crown broadly ovoid. Branchlets yellowish, terete, glabrous. Buds russet, ovoid, very viscid. Petiole ca. as long as or longer than leaf blade, laterally flattened, glabrous; leaf blade rhombic, rhombic-ovoid, or deltoid, 5-10 × 4-8 cm, thinly leathery, abaxially greenish, adaxially green, base cuneate or broadly cuneate, rarely truncate, margin crenate-serrate, ciliate, apex long acuminate. Flower buds outwardly curved at apex. Male catkin 5-6 cm; rachis glabrous; bracts brownish, 3-4 mm, membranous, laciniate. Male flower: stamens 15-30; anthers purplish red. Fruiting catkin 5-10 cm. Female flower: ovary ovoid, glabrous, stipitate; stigmas 2. Capsule ovoid, 5-7 × 3-4 mm, 2-valved, stipitate. Fl. Apr-May, fr. Jun. 2n = ?19*, 38*, 57.

Systems

• Terrestrial

Typically inhabits lowland floodplains (4) in river valleys (3) and needs open areas to allow germination (4). It also occurs in hedges and roadsides, and by ponds. Furthermore, it is sometimes planted in urban areas (9).

Along rivers. Native in Xinjiang; cultivated in Fujian, Hebei, Jiangsu, Liaoning, Nei Mongol, Shaanxi, Sichuan, Yunnan [N Africa, WC Asia, Europe].

Foodplant / internal feeder
larva of Dorytomus filirostris feeds within catkin of Populus nigra sens.lat.

In Great Britain and/or Ireland:
Foodplant / internal feeder
larva of Dorytomus ictor feeds within catkin of Populus nigra sens.lat.
Other: sole host/prey

Foodplant / internal feeder
larva of Dorytomus longimanus feeds within catkin of Populus nigra sens.lat.

Foodplant / pathogen
acervulus of Marssonina coelomycetous anamorph of Drepanopeziza punctiformis infects and damages live leaf of Populus nigra sens.lat.
Remarks: season: 7-9

In Great Britain and/or Ireland:
Foodplant / parasite
fruitbody of Agrocybe cylindracea parasitises branch of Populus nigra 'Italica'
Other: minor host/prey

Foodplant / spot causer
acervulus of Marssonina coelomycetous anamorph of Drepanopeziza populorum causes spots on live leaf of Populus nigra 'Italica'
Remarks: season: late summer
Other: major host/prey

Foodplant / gall
Pemphigus bursarius causes gall of leaf (petiole) of Populus nigra 'Italica'
Remarks: season: 5-7

Foodplant / gall
Pemphigus spirothecae causes gall of spiral-shaped gall leaf (petiole) of Populus nigra 'Italica'
Remarks: season: spring

Foodplant / gall
fundatrigenia of Thecabius affinis causes gall of live, down-folded leaf of Populus nigra 'Italica'

In Great Britain and/or Ireland:
Foodplant / parasite
fruitbody of Agrocybe cylindracea parasitises branch of Populus nigra
Other: major host/prey

Plant / resting place / within
puparium of Aulagromyza populi may be found in leaf-mine of Populus nigra
Other: sole host/prey

Plant / resting place / on
puparium of Aulagromyza populicola may be found on leaf of Populus nigra
Other: sole host/prey

Foodplant / saprobe
often long-stalked apothecium of Ciboria caucus is saprobic on overwintered, fallen catkin (male) of Populus nigra
Remarks: season: 3-4

Foodplant / saprobe
scattered to loosely gregarious, deeply immersed, then splitting epidermis, irregularly plurilocular stroma of Cytospora coelomycetous anamorph of Cytospora harioti is saprobic on dead twig (small) of Populus nigra
Remarks: season: 1

Foodplant / feeds on
Dorytomus affinis feeds on Populus nigra
Other: minor host/prey

Foodplant / feeds on
Dorytomus dejeani feeds on Populus nigra

Foodplant / feeds on
Dorytomus tremulae feeds on Populus nigra

Foodplant / pathogen
acervulus of Marssonina coelomycetous anamorph of Drepanopeziza populorum infects and damages live leaf of Populus nigra

Foodplant / parasite
fruitbody of Fomes fomentarius parasitises live, standing trunk of Populus nigra

Foodplant / gall
single or communal larva of Hexomyza schineri causes gall of twig (current year) of Populus nigra

Foodplant / saprobe
fruitbody of Hypsizygus ulmarius is saprobic on dead, standing trunk (large) of Populus nigra

Foodplant / saprobe
gregarious, immersed then erumpent, plurilocular stroma of Cytospora coelomycetous anamorph of Leucostoma niveum is saprobic on dead twig (bark) of Populus nigra
Remarks: season: 2-3

Foodplant / parasite
hypophyllous, subepidermal, scattered or in groups telium of Melampsora allii-populina parasitises live leaf of Populus nigra

Plant / resting place / within
epiphyllous, subepidermal, grouped, confluent telium of Melampsora laricis-populina may be found in dead, fallen leaf of Populus nigra

Foodplant / saprobe
fruitbody of Meripilus giganteus is saprobic on dead trunk (large) of Populus nigra

Foodplant / miner
larva of Messa glaucopis mines leaf of Populus nigra

Foodplant / miner
larva of Messa hortulana mines leaf of Populus nigra
Other: sole host/prey

Foodplant / saprobe
fruitbody of Ossicaulis lignatilis is saprobic on dead, decayed, fallen wood of Populus nigra
Other: minor host/prey

Foodplant / feeds on
pycnidium of Phomopsis coelomycetous anamorph of Phomopsis pallida feeds on branch of Populus nigra

Foodplant / spot causer
loosely gregarious pycnidium of Phyllosticta coelomycetous anamorph of Phyllosticta populi-nigrae causes spots on live leaf of Populus nigra

Foodplant / spot causer
epiphyllous pycnidium of Phyllosticta coelomycetous anamorph of Phyllosticta populina causes spots on fallen leaf of Populus nigra

Foodplant / saprobe
fruitbody of Rigidoporus ulmarius is saprobic on dead, white-rotted stump (large) of Populus nigra

Foodplant / saprobe
fruitbody of Schizophyllum amplum is saprobic on dying branch of Populus nigra
Other: major host/prey

Foodplant / feeds on
mainly epiphyllous, few, pallid pycnidium of Septoria coelomycetous anamorph of Septoria populi feeds on leaf of Populus nigra
Other: major host/prey

Foodplant / spot causer
Taphrina populina causes spots on live leaf of Populus nigra
Remarks: season: 7-9

Foodplant / parasite
Uncinula adunca var. adunca parasitises Populus nigra

Foodplant / saprobe
Phaeostromella anamorph of Valsa ambiens is saprobic on dead twig of Populus nigra
Remarks: season: 10-5

Foodplant / saprobe
somewhat scattered, covered, then erumpent, plurilocular stroma of Cytospora coelomycetous anamorph of Valsa sordida is saprobic on dead branch of Populus nigra
Remarks: season: 5-9,12-1

Foodplant / miner
larva of Zeugophora flavicollis mines leaf of tree (at least 8m in height) of Populus nigra

Foodplant / open feeder
adult of Zeugophora subspinosa grazes on leaf of sapling of Populus nigra
Remarks: season: mid 8-9,5-12

Poplar Scab (Venturia populina/Pollaccia elegans)
Since around the summer of 2000 a virulent disease has hit Populus nigra and in particular the selected male clone known as the Manchester Poplar; this in most cases leads to death over a three year period. The infection is caused by a fungal disease called Venturia populina, or its asexual stage Pollaccia elegans . A number of Venturia species cause diseases on other species of trees, the most common being apple scab. Known here as Poplar Scab, the Italians have termed it 'Summer Leaf Drop'. Abroad it is principally infecting varieties and hybrids of black poplar all of which occur in Greater Manchester but there remain unaffected. It is suspected that a new strain of Venturia has either developed, or arrived from abroad. Why it suddenly appeared in Greater Manchester with such virulence remains a mystery. There is a strong suspicion that climate change is playing a role. It is known that 2 weeks of wet weather in spring are needed for infection and if then followed by a hot summer, conditions are perfect. Once infected the tree remains infected. The infection is often coupled with the presence of other pathogens such as the Poplar Leaf Spot (Marssonina brunnea). Because of its possible devastating consequences for the native Water Poplar populations the spread of the disease is being closely monitored. Initial symptoms are hard to detect; it is more readily detectable in groups or rows of poplars where some will appear to have a slight browning of the leaves compared to surrounding individuals and canopy leafing is reduced. In the following spring, trees infected the previous season leaf-out but they do not produce the normal very dense canopy. By late June to mid July, they can lose up to 90% of their leaves. Re-foliation is attempted but leaves continue to drop until by early October the infected trees have no leaves left. New leaves initially show black lesions followed by a light brown shrivelled appearance similar to brown paper. Leaf fall in the autumn is an active process with the tree forming an abscission layer at the base of the petiole (leaf stalk). Because infected leaves are killed, they cannot form an abscission layer and so hang brown on the tree for some time.
As the leading new shoots are also killed back, new growth must arise from a point lower down the twig. Infected trees begin to develop a dishevelled appearance, obvious even to casual observers. The blackened drooping leading tip is a good indicator.
At some point before the actual death of the tree, it has been observed that the thick bark becomes detached from the underlying wood of the stem. Following wet weather, damp patches appear on the stem giving the appearance of a weeping canker. This is probably caused by rainwater gaining access higher up the stem and lodging in the space between the wood (the xylem) and the loose but intact bark. When pierced with a sharp implement, the rainwater flows out with a rusty red appearance. The bark is easily removed at this point and the inner bark (the phloem) presents a curious dark red stringy appearance. Once the trees die, the loose bark dries, cracks, and can be easily pulled off the tree in large sheets.
Trees that have been pollarded over the last few years succumb very quickly presumably due to their already being under stress and the new young leaves are more susceptible to infection.[www.aie.org.uk/trunkline/pests/aie_pd_popscab.html]Many other fungal pathogens of Poplar species are reported, some with a preference, or strict specificity for P. nigra and its close relatives.Other parasitesMistletoe (Viscum album). This well known stem-parasitic flowering plant frequently attacks Populus species and is often found on Hybrid Black Poplars but, interestingly, is very rarely found on pure P. nigra.

Widely distributed throughout Southern, Central and East Europe, North Africa and eastwards to Central Asia the Black or Water Poplar is almost certainly native to lowland England but as with many of our tree species its present distribution is largely artificial, the result of widespread planting. Nationally sources cite figures of c.7,500 trees, of which c. 600 are female (Jones, 2004)- these numbers are regarded by many experts to be inaccurate but the relative proportion of the sexes is unlikely to change greatly. The great disparity in the distribution and abundance of the sexes would be difficult to account for as a natural phenomenon. The distribution of diversity is being elucidated by DNA sequencing techniques; these have identified the wide distribution of particular vegetatively propagated and hence planted clones.Most trees are to be found south of a line from the Mersey to the Humber estuaries, with scattered occurrences northwards. Genetically distinct populations occur in the central plain of Ireland. The greatest concentrations in Great Britain occur in the Aylesbury Vale, but significant populations also occur in Wiltshire, along the River Severn and in Somerset, Suffolk and Shropshire. We currently know of about 300 trees in Greater London, a significant proportion of which are female.Past confusion with hybrids and their backcrosses and the mapping also of cultivars such as the Lombardy Poplar and recent conservation/amenity plantings mean that this map should be viewed with some caution. Careful search is still however revealing previously overlooked veteran trees throughout the British range.

Ecology
A species naturally occurring in open wet woodland and on forested floodplains, clearance and drainage since the Neolithic period have restricted the species to riverbanks, hedgerows and field margins. It does not tolerate dense shade well. In cultivation it is remarkably tolerant of a range of soil conditions and of atmospheric pollutants and has been widely planted in much drier localities than it would naturally occupy.

Fl. Per.: April-May.

The species is dioecious and over much of the extant British range there is a considerable disparity between the numbers of male (frequent) and female (rare) trees, a consequence of the deliberate selection of male clones (they do not cause problems through the production of debris associated with flowering/fruiting); in some parts of lowland England (eg. Sussex) ratios approaching 1:1 are still found but tree numbers are low and the sexes are not intimately associated. Natural sexual regeneration is thus extremely uncommon, not least because the conditions necessary for germination and early establishment are rarely present. The seeds are short-lived and must fall on bare, moist competition-free surfaces that are neither dry, or become flooded. Where conditions do allow germination, seedlings are likely to be hybrids as pollen contamination from the more abundant cultivated varieties is probable. The estimated radius for pollen travel is about 16km (Jones, 2004).Although the tree doesn’t sucker readily, natural vegetative propagation from layering of fallen individuals, debris washed down rivers, etc. occurs, but is less likely to happen now that watercourses are so managed and river and floodplain systems have become less dynamic. Damage to root systems through agricultural and other activities may encourage suckering.Water Poplar can be propagated from hardwood or softwood cuttings, the latter more easily. Early advice suggested using lengths of 15-20cm, from new growth made in the proceeding summer, taken while the tree is dormant; vigorous epicormic shoots are particularly suited to this purpose. These cuttings were then planted such that at least half their length was underground. Recently the use of longer truncheons, 1-2m lengths of vigorous vertical terminal shoot growth, trimmed at the base and rapidly planted to at least a depth of 30cm is recommended. Past bunch planting of cut shoots has given rise to dense clonal stands in some localities.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 8
Specimens with Barcodes: 20
Species With Barcodes: 1

Canada

Rounded National Status Rank: NNA - Not Applicable

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G5 - Secure

Although now acknowledged to be Britain’s rarest native timber tree, nationally there exists no special legislation to protect this species and for a long time it was overlooked (Mabey, 1996). Its cultural significance and the concerns over increasing threats and ongoing decline mean however that many local Biodiversity Action Plans have now adopted this species for targeted conservation action.The NHM acts as contact point for the Greater London LBAP on this species [www.lbp.org.uk/londonhabspp.html ] and within London many of the constituent Boroughs also have plans for its protection. Elsewhere the species is included in the following LBAP’s: [see http://www.ukbap-reporting.org.uk/]

• Cheshire
• Cotswold’s Water Park
• Durham
• Essex
• Greater Manchester
• Norfolk
• Northamptonshire
• Shropshire
• Staffordshire
• Suffolk
• Warwickshire
• Worcestershire

Management
Guidelines to the successful management of existing trees and the propagation and planting of new material have been produced by various local groups for distribution as leaflets eg. Noakes, 1999 and are also summarised in Jones, 2004.Many extant trees have had some history of pollarding, particularly in the Aylesbury Vale. This technique, best maintained on a 10-15 year cycle, can prolong the life of the tree but if done inappropriately can be fatal. Management work is best avoided following drought years, or where the tree may become drought stressed. Rather than removing the whole crown at once, a lop, or reduction, done over a 3 year period, initially leaving 2/3rds of the tree’s growth, will prevent damage. Cutting should be above the previous pollard line, the branches cut to leave a face sloping away from the crown of the tree. This work should be carried out between November and February.It is important that the age and condition of a tree are considered prior to any major works. Re-pollarding is not always the best option; older trees and those which have not been pollarded for decades may struggle to recover. Where management work on such trees becomes necessary it is recommended that cuttings are also taken.

Not listed under any major conservation designations.

The preferred habitat of this species has become very rare across Europe as floodplains have been modified and drained for agricultural purposes or succumbed to development pressures (5). Other threats include hybridisation with introduced poplars, which degrades the gene pool, competition with hybrids, and reductions in the groundwater table, which results in trees drying out and dying (4).

These species are introduced in Switzerland.

Plans to try to recreate the flood plain forest habitat favoured by black poplar, a habitat that is largely extinct in the UK, have been put forward (8).

It is the chief source of timber in the dry inner valleys were it is irrigated up to c. 4000 m (R. R. Stewart, l.c.). 

 Three varieties are recognized. Our material is in conformity with var. italica (Moench) Koehne, Deut. Dendrol. 81. 1893. (Populus italica Moench, Verz. Ausländ Bäume 79. 1785).

Comments: The naturalized North American material of Populus nigra, the European black poplar, is often called Populus nigra var. italica but is perhaps better treated taxonomically as a cultivar [Populus nigra 'Italica'], since it represents a one-time variant (with columnar growth form) of the species, found as a single tree in the Lombardy region of Italy several centuries ago, and propagated as cuttings.