Science Fair Project Encyclopedia
The White Poplar (Populus alba) is an aberrant species of poplar, most closely related to the aspens (Populus sect. Populus). It is native from Spain and Morocco through central Europe to central Asia, growing to heights of up to 16-27 metres. It has a thick trunk topped with a broad rounded crown, and the bark is smooth and greyish, but blackish and fissured at the base. The annual shoots are covered with whitish-grey down, including the small buds. The leaves are 4-15 cm long, five-lobed, with a thick covering of white scurfy down on both sides but thicker underneath; this layer slowly wears off through the summer. Larger, deeply lobed leaves are produced on fast-growing young trees, and smaller, less deeply lobed leaves on older, slow-growing trees.
The dioecious flowers appear at the end of March and the seed capsules mature in May to July. The White Poplar also propagates by means of root suckers growing from the lateral roots, often as far as 20-30 metres from the trunk.
The White Poplar grows in moist sites, sometimes by watersides, in regions with hot summers and cold to mild winters. It requires abundant light and ample moisture, and stands up well to flood water and slightly acidic soils. It is very attractive as an open-grown tree in water meadows, and, because of its vast root system, is used also to strengthen sand dunes. In intensive forest management it is being replaced by various cottonwood hybrids. The wood is soft, and used to make cellulose and for cheap boxes. A conical cultivar from Turkestan, Populus alba 'Pyramidalis' (Bolle's Poplar) is sometimes planted in parks.
In the past, the White Poplar was occasionally also known by the name "Abele".
White Poplar hybridises readily with the closely related Common Aspen (Populus tremula); the resulting hybrid, known as Grey Poplar (Populus x canescens), is intermediate between its parents, with a thin grey downy coating on the leaves, which are also much less deeply lobed than White Poplar leaves. It is a very vigorous tree with marked hybrid vigour, reaching 40 m tall and over 1.5 m trunk diameter (much larger than either of its parents).
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