The White Poplar is a large, generously leafy tree easily recognized by its dark leaves which toss in the breeze to reveal silvery-white, hairy undersides. With a maximum life span ranging from 300 to 400 years and easy propagation thanks to its root suckers, the White Poplar is a characteristic and frequent sight in the Danube wetlands.
Description
The White Poplar is a large tree with a straight or slightly crooked trunk. It rejuvenates mainly by way of its robust root suckers; natural multiplication by way of seeds is rare. This fast-growing tree species may reach a maximum height of 40m. It has a loose crown which sometimes droops off to one side. Life span may be 300 to 400 years. The bark of young trees is still smooth, whitish-grey to greyish-green, and exhibits characteristic dark, diamond-shaped marks (lenticels). In old age, the bark becomes increasingly rough, turning dark grey and developing deep vertical furrows. The pointed oval buds develop into multiform leaves on alternate sides of the stem. Leaves are 10cm long and 3-6cm broad and have three to five lobes; they are glossy dark-green on the top and white with woolly hairs on the bottom. The White Poplar earned its name from the underside of its leaves, which flash white in the slightest breeze. This dioecious tree flowers with catkins before the leaves, usually in March and/or April. Ripening around the end of May, its fruit has small hairless capsules which contain the oblong, pear-shaped seeds which have cottony hairs. A characteristic tree of the Danube wetlands thanks to the powerful and sometimes bizarre habit, or growth, of older trees.
Distribution
The natural range of this Eurasian species includes Southern, Central and Eastern Europe and extends to western Siberia, western Asia and northern Africa. In Central Europe its distribution is sporadic but most often occurring on rivers, and in particular on the Danube, Upper Rhine and along the Oder. The species has been acclimatized in Western and Northern Europe as well as in parts of Central Europe.
Endangerment and Conservation Status
Is widespread in all provinces of Austria; is only considered vulnerable in the Alpine regions.
Common, not vulnerable, in the Danube wetlands.
Ecological Characteristics
The White Poplar germinates in soils not rich in humus and prefers old, loose soils. But it can also tolerate compact gley soils, which is why this tree may often be found on backwaters, bayous or sedimentation zones. It occurs in the Alps up to elevations of 1500m. As a fluvial woody plant it can also be found in areas which are not regularly flooded, e.g. the hardwood riparian forests of the Danube wetlands. But due to its attractiveness to forestry operations (rapid turnover, propagation through root suckers etc.) it makes up a significant portion of stands.
Special Characteristics
Timber features broad sapwood and a yellowish-brown core. It is used to make paper, wood wool and fibreboard. As a mature tree, its impressive appearance is characteristic for a wetlands tree species; for eyrie-builders, the White Poplar is an important site for nesting.