Populus x canadensis
Canadian poplar (Eng), chopo canadiense, chopo híbrido (Spa), pollancre del Canadà (Cat), makal kanadarra (Baq), choupo do Canadá (Glg), choupo-do-canadá (Por).
DID YOU KNOW...? Forestry protection services call this species Populus x euamericana, following the decision of the International Poplar Commission, due to its genetic complexity and the fact that its lineage cannot be accurately traced. However, botanists consider P. x canadensis to be a valid name.
This tree is an artificial cross, created in the 18th century, between the Black poplar (Populus nigra L.) and the Eastern cottonwood (Populus deltoides Bartram ex Marshall). The result is a hybrid, polymorphic species that varies according to the different strains or parental clones used. However, in general terms, the trunk is straight and often very tall, reaching heights of up to 40 m. The bark is grey or greyish-brown, smooth when young and cracked in adult specimens. It tends not to have bumps or lumps as seen in other species, and it appears generally more open. It is characterised by its leaves, which are not rhomboidal, or deltoidal and narrow, like in the parent trees, but are instead large, triangular, or deltoidal and wide, with a straight base that is either wide or truncated. The margin is serrated or scalloped (with small waves). The shoots often have cilia, and there are usually glands at the base of the blade. The leaf stalk is very long and laterally flattened. Male and female flowers grow in elongated, hanging groups known as catkins. The fruits are capsules that open when ripe. The cottony masses seen floating through the air are often associated with allergies, as people confuse them with pollen, but they are actually the seeds. These usually come from female clones that release them in late spring or early summer, wrapped in a cottony cover that helps them to be dispersed by the wind. The seeds of black poplars and willows are similar, but are released earlier, in the spring.
This species has been widely used as an ornamental, particularly in riverside plantations, which are abundant on the Iberian Peninsula and in the Balearic Islands. It has become established in the wild in places conducive to its ecological needs, i.e., moist areas such as river copses, lake and reservoir margins, in temperate-cold or temperate climates. It is also frequently seen next to roads and motorways, on abandoned land in more humid areas, or taking advantage of the accumulation of water on slopes. This species occurs on all soil types, but not if they are permanently waterlogged with no renewal of the water, nor in very warm climates with mild winters. It is found from sea level up to 1500 m, and grows very quickly. It is very easy to reproduce vegetatively, simply by rooting cuttings or young branches. Like all species in the willow family, it is not a very long-lived species, although the oldest specimens can reach great sizes, even though they become hollow and rotten, often due to severe pruning or the breaking off of dry branches.
The Canadian poplar ranges throughout the Iberian Peninsula. It is grown for timber production in meadows and on alluvial lowlands, which are very fertile, to promote the growth of the cultivars, i.e., plantations of clones of this hybrid. In general, there are three production areas, with different characteristics according to the climate, method of cultivation, and soil type: the Duero basin, the Ebro basin and Catalonia, and the meadows of the Darro and Genil rivers in Granada.