Bastard black poplar
|Bastard black poplar|
Bastard black poplar ( Populus × canadensis )
|Populus × canadensis|
The hybrid black poplar or Canadian poplar ( Populus × canadensis also Populus × euramericana ) is a hybrid of the Canadian black poplar ( Populus deltoides ) and the European black poplar ( Populus nigra ). Due to the ease of propagation and the possibility of exchanging the cuttings material, the first hybrids emerged at the end of the 17th century. Due to their rapid growth and advantageous wood properties, these have spread rapidly and displaced the black poplar native to Europe. The identification of species-only black poplars is difficult. The clear distinction between the species and the hybrids is not possible through morphological comparisons alone. However, the distinction is made through biochemical-genetic methods.
The bastard black poplar is a tree up to 30 meters high and forms a continuous trunk with a narrow to broad ovoid crown. The shoots are rounded to slightly angular, usually glabrous or rarely hairy. The buds are resinous. The leaves are alternate, more or less triangular in shape, long, pointed and 7 to 10 centimeters long. There may be one or two glands at the base of the petiole. The leaf edge is serrated and glabrous on both sides, the stem is reddish. Poplars are dioecious and wind-flowered and form pendulous catkins . The female flowers have two-leaved ovaries , the male flowers are about 7 centimeters long and form 15 to 25 stamens. The fruits are leathery capsules that open with two flaps, the seeds are 1 to 1.5 millimeters long and have a tuft of hair at the base.
The crossing of the primary species only succeeds with Populus deltoides as a female and Populus nigra as a male partner. The hybrids can be crossed fertile with the parent species, creating a hybrid swarm with intermediate characteristics between the two parent species in a stepless mixture. It is therefore questionable whether there is still any homozygous Populus nigra in Europe without genetic admixture of the American species.
The following distinguishing features between Populus nigra and typical Populus x canadensis are given:
- Cross-section of the young shoots angular (in nigra round), bark predominantly furrowed lengthways (in nigra, reticulated), freshly sprouting leaves reddish (in nigra light green), at the base of the petiole of the leaf blade always with glands (in nigra mostly absent), female flower with three up to four (rarely only two) scars, fruit capsule with three to four columns (rarely two columns) opening (with nigra always two).
In addition, canadensis is far more frequently attacked by mistletoe .
The bastard black poplar grows in floodplain and bank trees on nutrient-rich, sandy, gravelly and loamy, moderately dry to fresh soils that can be weakly acidic to strongly alkaline. It thrives at mean annual minimum temperatures of −30 to −35 ° C (winter hardiness zone 4).
There are several clones in culture that are of forestry importance. The exact determination is only possible on annual plants propagated by cuttings. A distinction is made between the following forms of culture (selection):
- 'Gelrica', a fast-growing cultivar with a long, almost white trunk. Budding occurs mid-early, red-brown shoots are formed. The leaves are more or less triangular and roughly toothed. The top is shiny, fresh green.
- 'Marilandica', with a broad and multi-branched crown and branches branching off at obtuse angles. The shoots are early, the shoots are brown and quickly turn green. The leaves are rhombic-ovate with a long tip and a wedge-shaped base. The leaf blades are strikingly light green.
- 'Regenerata', with a broad, conical habit and more or less lively branches. Young twigs are finely hairy. Budding occurs mid-early, the young shoots are brownish, but quickly turn green. The leaves are triangular, glossy green and often have slightly reddened stems.
- 'Robusta', with columnar growth and almost lively branches. Young twigs are slightly hairy and reddish. Shoots early, young shoots are red-brown. The leaves are 10 to 12 centimeters long, coarse, triangular and sawed almost to the tip. The leaf blade is glossy green, the stem is reddish.
The bastard black poplar is an often cultivated deciduous tree whose wood is used industrially.
- Andreas Roloff, Andreas Bärtels: Flora of the woods. Purpose, properties and use . 3rd, corrected edition. Eugen Ulmer, Stuttgart (Hohenheim) 2008, ISBN 978-3-8001-5614-6 , pp. 461, 463 .
- Peter Schütt, Horst Weisgerber, Hans J. Schuck, Ulla Lang, Bernd Stimm, Andreas Roloff: Encyclopedia of the deciduous trees . Nikol, Hamburg 2006, ISBN 3-937872-39-6 , pp. 391-392 .
- Roloff, Bärtels: Flora of the woods
- Randy L. Smith & Kenneth J. Sytsma (1990): Evolution of Populus nigra (Sect. Ageiros): Introgressive Hybridization and the Chloroplast Contribution of Populus alba (Sect. Populus). American Journal of Botany 77 (9): 1176-1187.
- Gregor Aas: The black poplar (Populus nigra) - on the biology of an endangered tree species. LWF-Wissen 52nd published by the Bavarian State Institute for Forests and Forestry. on-line
- Determination aid for native and cultivated poplar species and varieties in Central Europe , by Michael Koltzenburg. on open-naturfuehrer.de. Retrieved April 11, 2016