Poplar (native black poplar)

Native black poplar
Populus nigra
var spp. betulifolia

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Native black poplar belongs to the genus Populus and is a member of the willow family (Salicaceae).

Native black poplar (Populus nigra var ssp. betulifolia) is a deciduous tree growing to 30m and flowering February to April.

Lifespan: can live over 200 years.

Characteristics

Bark is grey-brown, thick, rugged, deeply fissured and burred. Branches arch downwards. Twigs and buds are distinctly angular. Leaves are shiny, green, triangular, longer rather than wide and hairy when young. Leaf margins are finely toothed but not hooked. Leaves have long stalks.

Native black poplar is dioecious: male and female flowers are found on different individual trees. Male flowers hang together in pendulous catkins and each flower consists of a leafy bract fringed with hairs and a shallow, green cup holding many red stamens. Female flowers are also pendulous. Each tiny individual female flower has one bract scale and a four-styled carpel carried in a green cup. Poplars are wind pollinated.

Black poplar tree
Black poplar leaves

Distribution

Native in UK and across Europe.

Infrequent, with a patchy distribution in England, Wales and Ireland. Found mostly as isolated individuals on moist sites in wet woods or on the flood plains of lowland rivers and streams.

Populus species are known to hybridise with each other and there are a number of cultivated varieties of black poplar that are widely planted to provide fast growing shelter.

Native black poplar is declining due to low natural regeneration, and conservation efforts have begun in some areas to re-establish natural floodplain woodlands and revive the species. Although the native black poplar does not yet have a species action plan under the national UK Biodiversity Action Plan (BAP) it is included as a priority species in some local plans.

Human value

Native black poplar wood is light in colour, fine textured and soft. Its almost white colouring and lack of scent makes it valuable for use in contact with food (kitchen utensils). The wood can be used for joinery and veneers but it is not durable for use outside and the heartwood does not take preservative well.

Native black poplar has a long history of being used for timber. Valued for its shock-absorbing qualities is was used to make carts, floorboards and clogs. It was also used in the manufacture of matches.

Named ‘black poplar’ only by way of contrast to the grey and white poplars, it is also nicknamed ‘water poplar’ being a characteristic species of floodplain meadows.

John Constable immortalised the black poplar in many of his paintings of East Anglia; the most famous of which is The Hay Wain.

Black poplar flowers
Black poplar leaves

Wildlife value

Native black poplar is an important component of wet woodlands which are a priority habitat under the UK BAP. Wet woodland supports a wide range of charismatic floral species and the damp conditions found in these environments support specialist hoverfly, cranefly and a variety of mosses, lichens and fungi.

Native black poplar is a valuable wildlife tree having over 100 insects associated with it. Moth species include the hornet moth, wood leopard moth, poplar hawk moth and the figure of eighty.

Catkins provide an early source of nectar for bees and the seeds are enjoyed by finches.

The rare migrant butterflies the large tortoiseshell and the Camberwell beauty rely upon poplar and elm species for their food plants. A decline in both of these tree species has resulted in these butterflies becoming extinct in the UK.

Management

Native black poplars are light-demanding and need space around them to grow well and to exhibit their impressive arching form. They grow more slowly if competition is heavy, but are sometimes seen rising above or growing away from other trees in wet woodland habitats. They prefer well-drained to moist fertile soils such as alluvial soils or nutrient rich loams.

Propagation from seed is very rare in the UK. Seed may often not be viable (there is a shortage of female trees) or the exposed muddy conditions they favour may not be available. Root cuttings, root suckers or leafy softwood cuttings are usually used. It is advisable to consult an expert should you wish to grow a true native black poplar. For guidelines visit Forest Research.

Recent DNA analysis has shown that the majority of the national population has been planted by man. There are very few known examples of naturally seeded populations and little genetic diversity. This makes the species very susceptible to disease.

Poplar species can be prone to a variety of cankers and leaf rusts. A bacterial canker Xanthomonas populi can be serious and a rust Melampsora can cause leaf damage. Poplar scab can kill black poplar trees; the infection is caused by a fungal disease called Venturia populina. The aphid Pemphigus spyrothecae forms twisted galls in the petioles.

Black poplar tree

Illustrations © Reader’s Digest Association, Inc.
Photographs © Anne Westover