The Black Poplar is native to softwood riparian forests and lowland river valleys with gravel banks. It grows quickly and robustly and normally has a broad crown with irregular branch patterns. In ideal sites, Populus nigra may reach heights of around 30m and trunk diameters of 2m. Life span is approximately 100, but occasionally up to 300 years.
As mature trees, Black Poplars exhibit a markedly strong, gnarly habit. They have ample growth in the form of root and stump suckers. Characteristic are the many swellings on the trunk and early thinning of the crown. The crown is generally spreading with a somewhat irregular branch structure. The trunk of mature trees is characterised by the preponderance of knotty burrs and bark which is dark grey to black, rough and fissured in "X" patterns. Heights of up to 35m and trunk diameters of up to 2m may be reached. The yellow to reddish-brown buds lie close to the twig, but often have an outwards-arching tip, are sticky, hairless or with only wispy hairs. Twigs are relatively thin, rounded and yellowish brown. The alternating leaves are 5-10cm long, round to triangular, rhombic, with long tips; young shoots are reddish-green, turning glossy dark green above and somewhat paler on the underside. Like all poplar types, the Black Poplar is dioecious, meaning there are both male and female sexes, and anemophilous, or pollinated by the wind. Flowering takes place in April-May before leaves emerge. The fruit, which ripens in May, consists of small capsules which open up to release light-brown seeds with wispy white hairs.
The range of the Black Poplar extends from Europe to Central Asia. As river companion it may often be found in the valleys of major rivers: in Europe, the Loire, Rhone, Danube but also the Rhine, Elbe, Oder and Vistula. However, its true natural range is now difficult to determine due to active planting.
Endangerment and Conservation Status
The Black Poplar is generally classified as vulnerable in Central Europe and is one of the tree species described as critically endangered on the IUCN Red List. Although the tree may be found in all provinces of Austria, it remains vulnerable; in certain areas such as in the Alps and the Danube region, the category of endangerment is even higher.
The Black Poplar naturally dominates on gravelly sites or on elevated sandy banks. Although it generally tolerates relative aridity in the top soil, it requires access to the groundwater table. It is one of the few woody plants which can thrive on gravelly soils. Black Poplar riparian forests were once widespread on the rivers of the foothills of the Alps and the upper reaches of the Danube. Yet measures to improve the navigability of rivers and provide better flood protection – straightening as well as the construction of dykes and canals – has had a negative impact on the Black Poplar. Ecological and landscape-related changes brought on by hydraulic engineering efforts and individual claims to use are responsible for the displacement of the Black Poplar, but the wide scale planting of more economically-viable commercial poplar species has also played a role in crowding out the Populus nigra. Today, a variety of pan-European efforts are being undertaken to preserve the last remaining natural occurrences in order to ensure the survival of this impressive tree for generations to come.
The sapwood of the Black Poplar is whitish while towards the core it becomes light brown and relatively rough. The timber is light, soft and abrasion-resistant. Although less attractive due to its susceptibility to ring shake, the Black Poplar remains the most valuable native poplar timber and is used in the manufacture of wood wool, crates, household appliances, carvings and is also used in furniture and house construction. The Black Poplar - including parts of the bark, buds and the timber itself – has long been utilized in naturopathy. Various components of this tree exhibit antiseptic and healing properties, and some also work to lower fever and aid digestion. The Black Poplar's bizarre yet powerful habit – nowadays a rare sight – has made it an easily recognizable species but also an important breeding site for large eyrie-builders (such as the Black Stork or the White-tailed Eagle).