Populus nigra, the black poplar, is a species of cottonwood poplar, the type species of section Aigeiros of the genus Populus, native to Europe, southwest and central Asia, and northwest Africa.

Description

Black poplars are medium- to large-sized deciduous trees, reaching 20–30 m, and rarely 40 m tall. Their leaves are diamond-shaped to triangular, 5–8 cm long and 6–8 cm broad, and green on both surfaces. Normally, their trunks achieve up to 1.5 m in diameter, but some unusual individual trees in France have grown old enough to have much larger trunks – more than 3 metres DBH (Diameter at Breast Height).

The species is dioecious (male and female flowers are on different plants), with flowers in catkins and pollination achieved by the wind. The black poplar grows in low-lying areas of moist ground. Like most other pioneer species, the tree is characterized by rapid growth and is able to colonize open areas quickly. and as a distinct species P. afghanica by others; bark smooth, nearly white; leaves and shoots as subsp. caudina (see also cultivars, below).

The subspecies P. n. betulifolia is one of the rarest trees in Great Britain and Ireland, with only about 7,000 trees known, of which only about 600 have been confirmed as female.

Cultivars

Several cultivars have also been selected, these being propagated readily by cuttings:

  • 'Italica' was originally selected in Lombardy, northern Italy, in the 17th century. The growth is fastigiate (having the branches more or less parallel to the main stem), with a very narrow crown. Common in the Mediterranean region, it is adapted to hot, dry summers and grows poorly in humid conditions, being short-lived due to fungal diseases. It is a male clone. Around 40 to 50 years, this short-lived variety starts shedding branches and is very likely to be blown over in high winds, each successive tree lost exposing neighbouring trees, creating a domino effect.

thumb|A fastigiate black poplar cultivar of the Plantierensis group, in [[Hungary]]

  • Plantierensis group clones are derived by crossing 'Italica' with P. nigra ssp. betulifolia at the Plantières Nursery near Metz in France in 1884; they are similar to 'Italica' (and often mistaken for it), but with a slightly broader crown, and better adapted to the cool, humid climate of northwest Europe, where the true Lombardy poplar does not grow well. Both male and female clones are grown. This is the tree most commonly grown in Great Britain and Ireland as Lombardy poplar.
  • 'Gigantea' is another fastigiate clone, of unknown origin, with a rather broader, more vigorous crown than 'Italica'. It is a female clone.

See also

  • The Green Cathedral
  • Babisnau poplar

==References==<!-- BiolConserv137:248. -->

  • (French) Conservation of genetic resources of Populus nigra
  • Populus nigra - distribution map, genetic conservation units and related resources. European Forest Genetic Resources Programme (EUFORGEN)