Aspen (lat. Populus tremula L.) is a deciduous tree from the willow family (Salicaceae). It develops a tree of medium height, which can be 20 to 30 meters high on average. It has a shallow but well-branched root. The trunk of an aspen can be up to 1 m wide in diameter, and it is covered with bark about 2 cm thick. The bark of young trees is smooth and white to yellow-brown in color, and with age it becomes furrowed and fissured and takes on a dark gray color.
The crown of the aspen is airy and round in shape. Young shoots are shiny and covered with bright lenticels, they can be olive to dark red in color. The buds are also shiny, with a spherical shape and pointed tips and several bare and sticky light brown scales. They are 5 to 10 mm long.
The leaf buds are narrowly egg-shaped and pointed at the top, while the flower buds are spherical and somewhat larger. Aspen leaves are alternate, and grow on a thin and flat petiole 3 to 6 cm long. They are round in shape and have jagged edges, initially hairy and later bare. Their faces are dark green, while their reverses are slightly lighter. Leaves change color to yellow or red in autumn.
Aspen flowers are unisexual and dioecious, which means that male and female flowers grow on separate trees, and are located in the axils of the valves of last year’s shoots. The female flowers are hanging, dark brown fringes that can be 6 to 7 cm long, and consist of a green carpel and a pistil with two patchy, dark red snouts. The male flowers grow gathered in 7 to 10 cm long hanging fringes that turn red after flowering. The aspen blooms in March and April, before leafing, and is pollinated by the wind. The fruit is a narrow and naked quiver 7 to 9 mm long. It is gray-brown in color and contains several small yellow-brown seeds. It ripens during May and June.
Planting conditions: sunny places or places in partial shade
Soil: well-drained, neutral to acidic
Flowering time: March and April, before leafing
Canopy: airy and round
Tree height: from 20 to 30 m
Root: shallow, but well branched
Planting and propagation of aspen
In nature, aspen grows in light forests, along the banks of streams and rivers. It can grow in very wet, but also dry areas. Fertile, basic to acidic, sandy or clay soils suit it. It is fast-growing, and can be propagated by seeds and vegetatively, that is, by root shoots and semi-ripe cuttings in the summer and woody cuttings in the autumn months.
There are also aspen cultivars that are used for growing in large gardens and parks. One of them, a cultivar called ‘Erecta’, was awarded by the Royal Horticultural Society in England.
Cultivation and maintenance of aspen
Aspen is not often grown in our country, but if you do decide to grow it, choose a sunny place because aspen does not tolerate shade. In addition, it should have enough space in order for it to grow and develop the canopy without hindrance. Given that it has a well-branched root system, planting near sidewalks, concrete driveways, sewers, or any pipes should be avoided. It adapts to all types of soil, varying degrees of humidity and pH-value, but it will grow best in well-drained neutral to acidic soils.
In the first few years after planting, aspens require regular watering, which is done only when the surrounding soil becomes dry to the touch. Newly planted plants should be well watered, and the soil around them should be covered with a layer of organic mulch in order to better maintain soil moisture and prevent the spread of weeds.
Pruning the aspen crown itself is not necessary, but since it is an invasive species and young plants begin to develop from the roots approximately two years after planting, they must be pruned so that they do not spread and form a smaller bush around the tree. You can control the spread of aspen by removing all saplings as soon as you see them. You can prune the crown only if you notice that some branches are infected.
Diseases and pests
Fungal diseases caused by the pathogens Ciborinia spp. and Marssonina spp. can occur. Symptoms are discoloration and premature leaf fall. Brown spots appear on the leaves that are attacked by these diseases, which are bordered in yellow. Over time, the spots spread and merge, causing leaf tissue to die in those places. Since they do not cause much damage, fungicides are not used, but the spread of fungal infections is controlled by gathering fallen leaves and aspen twigs.
Application of aspen
Aspen has light, elastic wood and is extremely suitable for shaping, so it is used in carpentry, furniture production, matches and paper, and for firewood. Its soft wood is also used to make chipboard and veneer. From an ecological point of view, it is important because it is home to several different species of birds and mammals, and many species of insects and mushrooms like truffles benefit from it (it is important for the white truffle).
Buds and bark of aspen are used for medicinal purposes, which are used in folk medicine for the treatment of gout, sciatica, enlarged prostate and painful urination, as well as for inflammation of the respiratory tract. All parts of aspen contain essential oil, glycosides, organic acids and tannins, and the leaves also contain carotene and ascorbic acid or vitamin C.
History of aspen
Aspen is naturally distributed throughout Europe, and also grows in North Africa, Central Asia, and Eastern and Western Siberia. Genus name Populus was the name for poplar among the ancient Romans, and the name of the species trembling it was caused by the leaves fluttering in a gentle breeze. This is why aspen is also called aspen in the people. Once upon a time, it was believed that aspen absorbs negative energy and drives away evil spirits, so it was often planted near houses.
White-leaved trees
Aspen is one of the many types of coniferous trees. What all species have in common is that their leaves, which appear in the spring months, change color from green shades to warm red, yellow, orange or brown tones during autumn. Considering that the leaves fall from the trees before winter, we also call this type of trees deciduous trees.
Deciduous or deciduous trees differ in the height they can reach, the bark of the tree, the shape of the crown, the shape of the leaves, the type of roots, the appearance of fruits and flowers, etc. Most of these trees bloom in the spring with fragrant flowers that attract insects and thus pollinate. Fruits develop from the pollinated flowers, which are edible in some types of conifer trees, but not in others.
In addition to aspen, the most common species in our area are holm oak and cypress, elm, poplar, wild chestnut, hornbeam, ash, linden, elder, acacia, wild cherry, apple tree, sycamore, hazel, sweet chestnut, maple, alder, birch. , willow and trees of various fruit trees.
Photo: Hans/Pixabay