Black poplar (sedge). Why are poplars pushing? Does pyramidal poplar provide fluff?

Poplars are very fast growing, gaining height and leaf mass from the Willow family. Trees grow very quickly during the first 15-20 years of life, but quickly age and die. When the poplar blooms, some people enjoy the white poplar blizzard in the hot summer, while others suffer from allergies. All types of poplars purify city air. There are several dozen species of poplars on earth, many of them are hybrids, grown through the efforts of dendrologists.

Balsamic

The balsam poplar is native to Canada and North America. The usual height is 17-20 m; old fifty-year-old trees often reach a height of 30 m.

The diameter of the spreading poplar crown is 10-12 m; the thick trunk is difficult for two people to grasp, since its diameter can be up to two meters. At the base of the trunk, the bark of the plant is dark, uneven, with bursting, clumsy furrows; higher up the trunk, elastic, smooth skin of a white-gray hue begins.

The branches are covered with leaves 5-14 cm long and 4-7 cm wide. The shape of the leaves is round at the petiole and wedge-shaped, tapering to a sharp tip; the edges of the leaves are covered with finely toothed relief.

The leaf is smooth, with a cool leathery surface and a long dense petiole (2-2.5 cm), the upper part of the leaf is shiny, dark green, the color of the lower plate is gray-green, very light, the skeletal basis of the leaf structure is clearly visible from below.

The buds thrown out in the spring are large, elongated, up to 2 cm high. The buds and newly unfurled young leaves are sticky from a sticky resin coating covering them with a pleasant aroma.

A tree is considered mature only after 5 or 6 years. This poplar species is used to create living, windbreaks for fields and.

It is almost never used for landscaping cities and villages, although it looks very beautiful in group plantings consisting of a small group of trees.

Laurel leaf

Habitat: Western and Eastern Siberia, up to the Angara River. It grows in Altai, in the foothills of the Dzungarian Alatau. Distributed in river valleys on pebbles, on mountain slopes, and on crushed stone.

The height of the plant is from 10 to 20 m, the thickness of the trunk is up to 1 m in diameter. This type of poplar is not tall, the skeletal branches are spreading and few in number, and few new, young shoots grow on them per year. Therefore, the crown of the plant is not dense, slightly sparse.

Did you know? In total, there are 95 varieties of poplar trees growing on planet Earth.

The leathery cover of the trunk is gray with cracks. The tree is not very demanding in terms of lighting and lives on the poor. The roots of the laurel leaf are very deep; it can easily withstand the long, frost-rich Siberian winters.

The color of the bark of young shoots is light yellow, they are slightly pubescent. Escapes unusual looking, and with clearly visible ribs, as they mature, the shoots become round in diameter.
This ribbing of the shoots is due to longitudinal cork-like growths, which is hallmark this particular type of poplar. The buds are oval, sharp, brown-green, elongated, covered with a sticky and pleasantly smelling substance.

The foliage is large, leaf length 6-14 cm, width from 2 to 5 cm. The shape of the leaf is oval-elongated, narrowed towards the end, the leaf has a finely indented border, smooth to the touch, cool, leathery, with a two-color color (green-whitish). The blossoming foliage is sticky and light green.

Due to the frequent freezing of the branches, an abundant growth of young shoots occurs; this makes the crown of the tree seem extremely lush and very decorative.

Flowering in this variety occurs in May-June; the fringed earrings are whitish in color, loosely fluffy, and covered with yellow pollen.

The male form of catkins is cylindrical, from 3 to 8 cm long, they contain 20-25 stamens with filaments and anthers, the female form of flowering (catkins) has flowers sparsely located on them, a pistil with a two-lobed stigma. The blades on the pestle are located downwards.
After ripening (May-June), fruits in the form of quadrangular swollen balls are formed in place of the earring inflorescences. The finally ripened seeds scatter from the bursting testes. Poplars from the laurel family are used in plantings along highways.

Important! The poplar family is divided into male and female trees. But only females spread fluff around when flowering.

Pyramidal

Pyramidal poplar is a light-loving plant. Very tall, the species description indicates a maximum height of 35-40 m and a maximum lifespan of up to 300 years. Grows in Italy, the Caucasus, Ukraine, Central Asia, in Russia.

Loves neutral and slightly acidic, moderately saturated with moisture, but well lit by the sun. Grows quickly in the first 10 years. The head of the plant is narrow, clearly elongated upward, the branches are powerful, strong, growing at an angle of 90° relative to the trunk.
The cut diameter of the trunk can be up to one meter, has weakly defined annual rings, dark gray bark, cut with small cracks. It blooms with small flowers collected in long inflorescences in the form of earrings of male and female-looking, women's earrings are 5-7 cm longer than men's.

Flowering occurs immediately after buds break. The color of women's and men's earrings is also different, men's are burgundy, women's are light milky.

The young plant has smooth and elastic, light gray or light olive bark. The shape of the pyramidal poplar leaf is clearly triangular, with a wide, even base, sharply tapering towards the top of the leaf.

Like other species of representatives of Willows, the pyramidal one has shiny, dark green leaves with a white color along the lower plate, finely toothed along the edge. The leaves are attached to the branches with a short, strong petiole, slightly flattened lengthwise.

With the onset of autumn, the foliage turns yellow; in mid-October, the leaf cover crumbles to the foot of the trees.
The roots of this plant are located deep down and wide, some of the roots are usually located on the surface of the ground near the base of the tree. Grows well in urban environments, there is no negative reaction to emissions of automobile gases into the air.

Black (sedge)

Black poplar or Osokor - has become widespread in Russia and Ukraine, grows in parks and squares, in deciduous forests. It is used in city landscaping due to its exceptional ability to release oxygen.

One plant can produce as much oxygen as 10 and three large, old ones. In one summer season black poplar purifies city air from 20 kg of dust accumulations; its buds also have healing properties and are used in folk medicine.
During its life, the giant reaches a height of 35 meters, its lifespan is from 60 to 300 years. Old trees are spreading, stocky, with a powerful trunk, covered with skin growths, which over time hardened and became shapeless wood. The bark is rough, almost black.

The buds are tightly pressed to the branches, round, large, with light scales, covered with gluten. The leaves are hard and large, triangular or diamond-shaped, attached to the branches by flattened cuttings.

Flowering - long catkins, burgundy and yellow, male and female varieties. Male and female flowers differ in the color and length of the inflorescences; female inflorescences are usually twice as long and more magnificent.
Flowering occurs in late May or early June. After seed ripening, dispersal (reproduction) begins. The poplar family has earned recognition and love in different parts of the world globe its diversity, rapid growth and unpretentiousness.

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Poplar (Populus), has about 35 species, a genus of fast-growing, short-lived trees of the willow family (Salicaceae). Homeland - Northern Hemisphere, where poplars grow from the Arctic to the subtropics. Sizes vary from medium to large: in many species the maximum height is about 30 m, and the trunk diameter reaches 2.4 m. Poplar is characterized by the pale velvety bark of young shoots and the rough, deeply cracked bark of old trunks. All poplars are easily propagated vegetatively (by root suckers, cuttings, stakes), are widely used as soil- and water-protective trees, and some species are used as ornamental and landscaping trees.
Black poplar (sedge) Populus nigra L. - a tree 18-40 m high, of the willow family. Its name is given by the color of the bark, which is dark gray, almost black; the leaves are broadly ovoid in shape, with a serrated edge, glossy on top. The flowers look like long hanging earrings. Men's earrings are purple-red. Black poplar blooms before the leaves bloom. It is widespread in middle lane Russia. Prefers to grow along river banks and in low places.
One of greek legends talks about how poplars appeared on Earth. Phaeton (the son of the Sun god), in order to prove his divine origin, decided to ride across the sky in Helios’s chariot, but could not cope with the team, which, sweeping away everything in its path, rushed from the sky to Earth. Zeus struck the chariot with lightning and smashed it to prevent all life on Earth from dying. The phaeton died in the waves of the river. Phaethon's sisters mourned immensely, and the Sun did not shine that day. The gods took pity on the grief of the sisters and turned them into slender trees sacred to the Greeks - poplars. Poplar is used in forestry to obtain cheap wood (by the age of 20 per 1 hectare, poplars can give such an increase in wood as oak and pine plantations provide only by 100 years), in agroforestry for afforestation of steppe areas, strengthening ravines, banks, plantings along roads and reservoirs and for landscaping settlements.
At present, black poplar is widespread in almost all cities of the European part of Russia. Black poplar is the fastest growing tree species in the zone temperate climate. It is widely used in creating protective plantings around industrial zones, along transport and railway routes, along the banks of rivers and canals. Sticky poplar leaves are excellent orderlies. They clean the air of dust, soot, and various substances that pollute the atmosphere. The green crown of each tree traps tens of kilograms of dust. These trees enrich the city air with oxygen, releasing it in greater quantities than our other green friends. All this indisputably indicates that poplars should decorate the streets, squares and parks of our cities. However, there is also negative side- this is poplar fluff that annoys people, causing allergies and asmatic attacks.

Sometimes poplar fluff causes fires.

Poplar fluff

To prevent poplar fluff from causing harm, these trees must be planted skillfully. The fact is that black poplar is a wind-pollinated species and is strictly dioecious, that is, it has male and female specimens. Down producers are only female trees. After flowering and the release of pollen, which is hardly noticeable to the eye, the catkins on male trees soon fall off, and on the catkins of female trees, fruits begin to develop, which ripen a month or two after flowering. The capsule fruits contain many small seeds with tufts of white silky fine hairs, which are carried by the wind after the capsules open. This is poplar fluff. After the seeds fly out, many catkins also fall and litter the streets.

Therefore, for urban greening, only male specimens should be planted, and then there will be no poplar snowstorm. Now, unfortunately, in many cities female poplars predominate. This is a big mistake, which is sometimes made out of ignorance, and more often through negligence, by employees of landscaping trusts. It would be correct if nurseries involved in the propagation and cultivation of poplars for urban landscaping created mother plantations only from male poplars.

Determining the sex of a tree is not difficult. At the end of winter, they take a flower bud from a branch, break it in half or separate only the upper part of the bud and look at the break under a magnifying glass with tenfold magnification. In male trees, the perianths are filled, like caviar grains, with underdeveloped anthers, yellowish (in winter) or purple ( in early spring). Female flowers do not have such caviar grains. Under a magnifying glass, an ovary with a stigma primordium is visible on the perianth. U different types Poplars are whitish-yellow or greenish-yellow in color.

There is also a way to prevent the appearance of fluff on female poplars. At the end of winter or early spring, the branches need to be pruned, although this operation is very labor-intensive. It is imperative to remove last year's growth, on which the flower buds are formed.

The range of poplars used in urban landscaping is, unfortunately, too poor. It is usually limited to wild poplar species - balsam, Chinese, white, Canada and a few others. Meanwhile, forestry breeders, through hybridization, have obtained many new forms of beautiful and fast-growing poplars.

Everyone is familiar with the beautiful silvery pyramidal tree that decorates southern cities. This is a green Turkestan poplar, or Bolle poplar. It is represented in nature only by male plants, which means it does not produce fluff. However, this poplar is very thermophilic and grows poorly north of Kharkov. In the central regions, winter-hardy white poplar grows well, but it is less decorative. By crossing white poplar with Bolle poplar, breeders developed new poplar hybrids that inherited a beautiful pyramidal shape from Bolle poplar, and winter hardiness from white poplar.

Many other hybrids have been developed that are suitable for landscaping cities in various climatic zones: Sverdlovsk poplar - for the Urals, Kursk - for the forest-steppe regions of the country, Kamyshinsky - for the steppe. For landscaping cities located south of Orel, such very decorative hybrid varieties poplars like Robusta, Bachelieri, Vernirubens. All of them should rightfully take their rightful place in the green attire of the streets, squares and parks of our cities.

Poplar fluff - poplar seeds

The widely known “poplar fluff” is the seeds of poplars along with hairs, thanks to which the seeds are easily dispersed by the wind. You can collect poplar seeds from the ground (in those places where, thanks to the wind, noticeable lumps of poplar fluff collect), or you can directly from the trees - at a time when the seed boxes begin to open and the seeds begin to fly away.
Collected seeds remain viable for a very short time - from several days to several weeks. Therefore, it is best to sow them almost immediately. To do this, you need to prepare a small bed (preferably in an area that is most thoroughly cleared of weeds), level its surface with a rake, and then spread the collected lumps of fluff with seeds on the leveled surface (either evenly over the entire surface of the bed, or in rows). After this, pour water from a watering can onto the decomposed fluff - as a result, the hairs on the seeds will stick together and the seeds will end up directly on the ground. Do not cover the seeds with soil - let them remain right on the surface.

Water them regularly, so that the surface of the earth is moist all the time; You can also cover it with some kind of covering material (for example, polyethylene) for the first two or three days. In just a few days, shoots will appear. When the seedlings reach a height of 5-6 cm, they must be thinned out so that the distance between plants is 5-10 cm (otherwise the thickened seedlings will interfere with each other’s growth). By autumn you will receive poplar seedlings suitable for permanent planting.

Use of black poplar in medicine

Leaves and buds are used for medicinal purposes. The buds contain many essential oils, tannins, coloring and resinous substances, vitamin C. They are collected in early spring, at the beginning of the tree’s flowering, dried in a well-ventilated area, or in dryers at a temperature of 25-30°C.

Medicinal properties of black poplar

Poplar preparations have anti-inflammatory, analgesic, wound-healing, antiulcer, astringent, sedative, antipyretic, diaphoretic, antipruritic, antimicrobial and antiviral properties. The presence of essential oil is associated with such properties of the kidneys as expectorant and regulating the activity of the gastrointestinal tract.

poplar bark

A decoction of the bark is taken orally - as an antimalarial, hemostatic; for intermittent fever, gout, rheumatism and sciatica.

Poplar buds

Alcohol infusion and extract of honor poplar are taken orally - for malignant tumors (together with other plants), tuberculosis, rheumatism, gout, scurvy, sciatica, intermittent fever, cystitis and other diseases Bladder, spermatorrhea, dysmenorrhea, diarrhea, colds; as a hemostatic, sedative, expectorant. A resinous balm is extracted from the buds, and “poplar ointment” is prepared from the extracts for external use as a disinfectant, antipyretic, distracting, emollient for gout, rheumatism, joint diseases, trichomonas colpitis, staphylococcal and fungal skin diseases, boils, wounds, burns, ulcers , hemorrhoids, cracked nipples, alopecia.

poplar leaves

Juice fresh leaves Used for toothache and for soothing baths.

Healing recipes with poplar

A tincture (1:5) is prepared from the buds of black poplar. Take it orally 15-20 drops 3 times a day as an analgesic, astringent and disinfectant for burns, gout, rheumatism, cystitis, hemorrhoids, cancer and other diseases. To prepare the ointment, you need to take the powder from the kidneys and mix it with a fat base in a ratio of 1:4.

Poplar buds can be boiled in vegetable oil in a ratio (1:10) and the resulting oil can be used 1 teaspoon 3 times a day with meals as an analgesic and anti-inflammatory agent for urolithiasis.

To prepare the ointment, take 3 tbsp. spoons of kidneys, chop them well, gradually mix with three tbsp. tablespoons of fat base and use for joint diseases, gout, boils, purulent wounds, burns, staphylococcal and fungal skin diseases, cracked lips, nipples, trichomonas colpitis.

An infusion of buds and leaves is prepared at the rate of 2 tbsp. spoons per 250 ml of boiling water (they are poured into a thermos and left for 3-6 hours), drink it 1-2 tbsp. spoons 3-4 times a day with meals. The decoction is prepared in the same ratio. Boil the raw material for 10-12 minutes, leave for 1-2 hours and take 1-2 tbsp. spoons 3-4 times a day.

Young poplar leaves can be used to prepare baths.

Infusion of black poplar buds: 1 tablespoon of raw material is poured into 100 ml of boiling water and left in a closed container for 4-6 hours, then filtered. Take 1 tablespoon 3 times a day.

Ointment from black poplar buds: grind 1 tablespoon of dry crushed buds with 1 tablespoon of lanolin or 1 tablespoon of butter.

Poplar wood

Poplar wood is moderately soft, light, quite light, fragile (impact resistance is especially low). It is used mainly for the manufacture of boxes and packing cages, containers and cooperage products, interior parts of furniture, wooden utensils, troughs, tubs for packaging butter and other food products, stuffing shavings and matches; for the manufacture of sleepers, plywood, joinery and turning products. In addition, it is used to produce cellulose, paper and artificial silk (viscose). In ancient times, shields were made from it. Floats for fishing equipment are made from old trees. Barrel burls are a finishing material for furniture and crafts.

Bark and leaves are used for tanning leather, dyeing leather yellow, fabrics yellow, chestnut, chocolate and brown.

Application of poplar in other areas

Poplar essential oil(from the buds) is suitable for flavoring soap and as a fixative. The buds stain the tissues yellow. The hairs from the seeds are suitable as one of the components for making felt and for making paper. Apple and pear fruits treated with phytoncides from black poplar leaves are more resistant to diseases both during the growing season and during storage.

In the perfume industry they are used to flavor toilet soaps. Poplar buds are part of Riga balsam. Fresh and dried leaves are good feed for cows and horses.
Poplar is an excellent honey plant. Glue from bee buds is used in the production of propolis.

Most North American poplars were brought to us from Europe to XVIII-XIX centuries. Others are from India and China. Widest distribution in the area central Russia received poplar-sedge. In total, 110 species of poplars grow on Earth, as well as a large number of their varieties and hybrids. We have 30 species, 12 of them are cultivated.

Active implementation of the program for landscaping new neighborhoods under construction began immediately after the war. The task was simple: choose an unpretentious and fast-growing tree, and plant it in areas allocated for landscaping near houses, along the edges of roads, in park areas. Poplar turned out to be such a “universal” tree - one of the champions in terms of growth rate. Each year, each tree becomes closer to the sky by an average of 2-4 meters.

Soviet scientists emphasized: poplars in cities are a temporary “green injection”; in 15 years it is necessary to begin replacing “fast greeners” with other trees that cause less trouble. However, even after 50 years, they did not begin to implement the replacement program, but they successfully introduced more and more doses of “green injections” into the “body” of megacities, provincial cities and towns throughout Russia.

Error or natural selection?

The “victorious march” of poplars turned into almost a tragedy: people began to grumble louder and louder about the fluff that covered the streets with a “snowy” carpet, “sneaked” into houses, and made them sneeze.

Questions started pouring in. Couldn't they have chosen a different tree? How could such an unfortunate mistake be made?

In fact, Soviet scientists were not mistaken in their choice. The fact is that poplar has “male” and “female” trees. The former bloom and pollinate the latter, and it is on the “female” poplars that seeds with fluff that irritates everyone appear. For landscaping, “male” poplars were chosen, which “do not push.” However, over time, botanists, to their displeasure, began to notice the appearance of “female” earrings on “male” trees. By “changing sex,” poplars tried to resist the massive seasonal “haircut.”

However, there is another version of the appearance of “female” poplars on city streets. During the Soviet years, gardening programs were often implemented at community clean-up days, in which ordinary citizens took part. It was simply unrealistic to invite a professional dendrologist to every community cleanup, who would identify and approve “male” poplars suitable for planting.

Harm or benefit?

Poplar fluff is not an allergen. It only spreads pollen from plants, the flowering of which turns into trouble for people prone to allergies. However, poplar fluff, being a mechanical irritant, causes sneezing and coughing, and causes discomfort in many Russians.

In 2008, Eco-portal published research by American scientists who stated that poplars can eliminate the consequences negative influence on the environment, including absorbing and breaking down the carcinogenic industrial solvent trichlorethylene, as well as other pollutants environment: gasoline, chloroform, vinyl chloride and carbon tetrachloride.

Russian professor, head of the department of clinical immunology and allergology of NMAPE named after. P.L. Shupika Larisa Kuznetsova is convinced that poplar fluff, like an “air brush,” absorbs carcinogens and heavy metal salts that enter the air from cars and industrial emissions.

Experts note that one poplar produces as much oxygen as 10 birches, 7 spruce trees, 4 pine trees or 3 linden trees. Over the course of a season, a tree “takes” 20-30 kg of soot and dust from the air. Poplar is extremely frost-resistant and is ready to adapt to the worst ecology, so finding a worthy replacement for it, according to environmentalists, will not be easy.

The head of the forestry program of Greenpeace Russia, Alexey Yaroshenko, is confident that if all the poplars are removed in Moscow, the air quality will decrease so much that it will cover all the benefits of the lack of fluff. The ecologist is confident that large polluted cities do not provide an alternative: other trees, given the current air condition, will grow very poorly, if at all.

Fighting methods

Today, one of the most effective measures to combat poplar fluff is seasonal pruning. True, not in all Russian cities public utilities cope with the task at the proper level. While utility workers can still get to the central streets, they often don’t get to the courtyards and outskirts. So the janitors and volunteers are trying to collect and sweep away the poplar fluff to no avail.

Often children who like to set fire to “summer snow” come to their aid, which, understandably, does not cause delight among the authorities - citizens begin to be persistently reminded of the fire hazard of poplar fluff.

Pruning, by the way, has its downsides. Firstly, after being “cut”, the tree looks ugly for some time, which does not contribute to improving the urban appearance. Secondly, ideal pruning should be completed by applying a special healing composition to the wounds of the tree, which does not allow the tree to collapse. It is clear that landscapers have neither the energy nor the time to carry out such painstaking work. Trees rotted from the inside fall, destroying cars and injuring people. However, old trees also create emergency situations - average duration The life of a poplar is 100 years.

In Moscow and a number of Russian cities, for example, Samara and Tomsk, planting poplars is prohibited. At the same time, comprehensive programs, which involve crowning, the use of special reagents that do not allow the seeds to open, and the gradual replacement of poplars with other types of trees - linden, birch, chestnuts. Cutting down all the flowering poplars at once means “denuding” the city streets.

What do they have?

Even the ancient Greeks willingly used “male” poplars, planting them in squares and central streets. It was from the Greeks that plant science borrowed the word “populus” - “folk” - for the name of the poplar genus.

Napoleon was a passionate fan of poplars. According to legend, he ordered these trees to be planted throughout Europe along the route of his army. The great Corsican was sure that he would return triumphantly along the green alleys of fast-growing poplars.

IN modern Europe, according to the presenter research fellow Latvian Botanical Garden Inare Bondare, the express gardening program has been fully implemented. “Male” “non-dusting” poplars were planted and, over time, replaced.

Various types of poplar are widespread in Canada and the United States. In some American cities, planting “female” poplars is prohibited for the same reason - to avoid a “blizzard”. On special plantations, sterile hybrid varieties are grown, on which seeds do not develop; they are used primarily for the production of cellulose.

Americans use flexible poplar wood to make snowboards, boats, boxes, pallets and even electric guitars. University of Michigan biologist Curtis Wilkerson proposes using genetically modified poplars as an effective and cheap biofuel.

In Edmonton, Canada, starting in 1980, a program was implemented to replace poplars with other trees. It only affected urban areas, but wild trees continue to cause many problems for city residents. For residents who dream of planting a poplar near their home, as well as landscape designers who want to use this tree to decorate their gardens, Canadian authorities strongly recommend choosing only “male trees” or sterile varieties in special nurseries, and in addition, promptly replacing old trees.

Not every tree has the ability to secrete poplar fluff: male plants are harmless and do not cause trouble. Therefore, people who plant these plants do everything possible to prevent females from appearing on the city streets.

But everything is not so simple: poplars have one unpleasant feature. They are very fond of changing their gender when, for unknown reasons, female catkins suddenly form on a male plant. This mainly happens in major cities with unfavorable environmental conditions. For this reason, culling female trees does not particularly solve the problem of the presence of poplar fluff.

Poplar trees belong to the genus of deciduous trees from the Willow family. They are common in temperate latitudes Eurasia and North America, while capturing part of the subtropical regions of China and Mexico, and are found in East Africa.

In nature, they grow along rivers and on well-moistened slopes; some species can be found in the sand. At the same time, they need soil rich in micro- and macroelements and do not tolerate swampy areas. At the same time, cultivated plants take root perfectly on any land.

The poplar genus has more than a hundred species, which are divided into six main sections:

• Mexican - plants of this group have the smallest height. They are a cross between aspen and poplar, common in Mexico and the USA;
• Deltoid - triangular-shaped leaves are located on long petioles. These trees are characterized by a pyramidal crown;
• Leucoid - considered the most ancient group poplars. The leaves, catkins and buds of poplar of this species are characterized by large sizes;
• Popolus or folk - representatives of this group are distinguished by the fact that their buds and leaves do not secrete a sticky substance, and they are also characterized by the presence of long petioles, which is why the foliage begins to move at the slightest breath of wind. The leaves have a palmate lobe shape and are characterized by snow-white pubescence on the underside. The most famous representative of this group is the silver poplar;
• Balsamic - the leaves and buds of trees are characterized by the presence of a huge amount of fragrant resin;
• Turangi - from a distance very similar to aspen, but have a looser crown.

Description

The height of poplar trees ranges from 30 to 60 meters, the diameter of the trunk is about a meter. Poplars grow very quickly and already at the age of forty years they acquire their final height (if they grow, it is not much), for which at one time this plant was given preference when landscaping streets.

The plant does not live long, usually up to eighty years (old poplar is highly susceptible to fungal diseases), although some species live up to one hundred and fifty.

Poplar roots are thick, strong, and in many species they are located superficially, and therefore extend quite far away from the tree. At the same time, some species, for example, silver poplar, produce many offspring on their roots, from which new trees grow.

The wood of the tree is soft and very light, the trunk is straight, the crown can have the most various shapes: tent-shaped, ovoid, ovoid-pyramidal or Lombardy poplar. The gray bark of a tree becomes covered with small cracks with age, while a poplar branch, on the contrary, has a smooth bark.

Both the leaves and flowers of the plant develop from the poplar bud. Poplar leaves are petiolate, arranged in a spiral along the branch; in some species the poplar leaves are pubescent, in others they are bare. It is interesting that the shape of a poplar leaf largely depends on the shoot on which it grew and even its location on it. Therefore, the same poplar leaves can have a wide variety of leaves - narrow, medium, wide.

Reproduction

Poplars are dioecious trees: to prevent self-pollination, male and female flowers are located on different plants. The sex of a tree is fairly easy to determine before the plant flowers. To do this, remove the bud from which the flower will develop, break it and examine its upper part under a magnifying glass. If the tree is male, grain-like anthers will be visible on the cut, while female trees do not have grains: instead, they have an ovary with a stigma primordium.

The plant begins to bloom in the tenth year of life, like many trees, in the spring or before, or simultaneously with the appearance of leaves. At a certain moment, the sticky poplar buds swell very quickly and immediately bloom. When the flowers appear, the buds remain on the tree for some time, after which they fall off.

The flowers of the plant are collected in inflorescences, shaped like earrings (they may have different shape: cylindrical, straight or hanging). Catkins growing on male trees are characterized by a red color, while female inflorescences yellow color with green pistils.

Plants are pollinated in the spring with the help of the wind, which picks up pollen from male trees and transfers it to female plants. As a result, female flowers turn into Green colour boxes that turn black as they ripen.

The box contains black seeds (more than a thousand pieces in one gram). At the base they have a tuft of a huge number of thin hairs, known as “poplar fluff”.

One and a half to two months after pollination, the boxes open, as a result of which the poplar fluff scatters in all directions, and the trees are covered with a white fur coat. Despite the huge number of seeds, most of does not take root: they lose their germination very quickly, so if the poplar fluff does not have time to deliver them to suitable soil, they disappear. Since the seeds are very light, in order to gain a foothold, they need to cling to something (a pebble, a twig, a straw), otherwise the poplar fluff along with the seed will fly away further.

Harmful effects on human health

Doctors say that patients began to complain about poplar fluff only in the seventies of the last century, when the air in cities began to become more and more polluted every year. Poplar fluff itself can only cause irritation of the mucous membrane, but the fluffs are ideal carriers of pollen and dust, which cause allergies in many people (for example, ragweed blooms can cause such a severe allergy that an allergic person may end up in intensive care).

Another negative point is that poplar fluff has the ability to instantly flare up from any spark, causing numerous fires in the forest (people often make their contribution when they have fun setting fire to the snow-white fluffs).

It’s not just down that’s harmful: often the trees themselves are dangerous. For example, an old poplar tree not only has soft wood that can easily rot, but also weak roots, which makes it extremely unstable. This means that during a thunderstorm with strong gusts of wind, the old poplar can fall at any moment. In the best case, the poplar will fall on the road or buildings, in the worst - on vehicles or people, which can lead to human death.

The benefits of poplar

Doctors say that at one time these trees were planted on city streets for a reason: they absorb about 70% of street dust, dirt and smoke (one old poplar clears the air of forty kilograms of soot and dust), refresh and enrich the air with phytoncides, killing pathogenic microbes. Interestingly, poplars emit several times more oxygen than conifers.

Thanks to the unpretentiousness of these trees, as well as their rapid growth, after the war it was possible to create green spaces for various purposes quite soon. It turned out that an old poplar tree growing near the house, whose height is fifty to sixty meters, serves as an excellent lightning rod.

It turned out to be especially beneficial to plant it within the city, since it not only grows quickly, but is also decorative and has a high ability to reproduce. If previously landscapers tried to separate male individuals, now many species of trees have been discovered (for example, species such as laurel and pyramidal poplar) that do not have poplar fluff, and therefore are the best option for the city.

At the same time, the old poplar, despite numerous proposals, is not cut down, but they try to trim it in such a way that one can be spared the pleasure of contemplating poplar fluff for about five years.

The invention relates to the field of forestry and fruit growing. The method includes determining external signs during the growing season. When flower buds form, they are cut and under a magnifying glass with 10x magnification, the male gender is determined by the filled round yellowish perianths with anthers, and the female gender is determined by their absence. The method makes it possible to simplify the determination of poplar sex, increase forest productivity and prevent the appearance of fluff. 1 table

The invention relates to fruit growing and forestry and can find application in poplar cultivation in forested areas. There is a known method in which the main difference between male and female plants is that the flower buds of female plants at the base with a thickness of 7 mm and a height of 10 mm have a pointed apex, forming a projection isosceles triangle, while the flower buds of male plants with similar measurements have a clearly defined round shape (I.K. Trosko, Soviet Subtropics, No. 8, 1940).

However, this method is applicable for trees aged 18-20 years and does not determine the sex of plants at early age, which is important for removing female plants.

The purpose of the invention is to simplify the method of determining the sex of poplars and increase forest productivity.

This goal is achieved by determining the sex of trees by the presence of perianths filled with yellowish anthers in male trees, and the absence of them in female trees, and more male trees are planted.

The method is carried out as follows: given the wide competitiveness of poplars, plantings should be grown, as a rule, clean. However, to increase their productivity, it is advisable to introduce soil-improving tree species into poplar crops, primarily alder and shrubs - red and black elderberry, yellow acacia, as well as lupine, alfalfa, beans and other legumes.

Poplar is very rarely bred by seeding. When such a need arises, you should collect the seeds in May, as soon as they are ripe, and sow them immediately, since poplar seeds very soon lose their ability to germinate. All poplars have vegetative propagation stump shoots by stem cuttings, and white, gray and aspen by root shoots.

As planting material, it is recommended to use large-sized 1-2-year-old ordinary seedlings or barbatella seedlings (with a 2-year-old above-ground part - a stem and a 3-year-old root system). This does not exclude the possibility of creating crops and planting cuttings and seedlings.

In order to determine the sex of a poplar, at the end of winter, they take a flower bud from a branch, break it in half and look under a magnifying glass with tenfold magnification. In male trees, the perianths are filled with underdeveloped anthers similar to caviar grains, yellowish (in winter) or purple (early spring). Female flowers do not have such grains; under a magnifying glass, an ovary with a stigma rudiment of a whitish-yellow or greenish-yellow color is visible on the perianth, depending on the type of poplar.

Poplar is a wind-pollinated species and a dioecious plant, one way or another having male and female specimens. Female specimens produce more fluff. The fruits ripen in late spring. Mature capsules immediately open, small seeds fly out of them, equipped with silky hairs, which the wind carries to a long distance from the mother tree. Therefore, male specimens should be planted for urban greening.

According to the agricultural technology of cultivation, fast-growing poplar crops are considered plantation crops, the main differences of which from conventional plantings are intensive agricultural technology of cultivation, low density of use of fertilizers, and often irrigation, which reduces the logging turnover and provides large reserves of wood.

Example. The soil for forest crops was prepared by continuous plowing, planting was carried out as a monoculture, placement 4 × 1.5, with a calculation of 1666 pcs. for 1 hectare. The crops were intensively cared for, which included applying fertilizers, weeding between rows, sowing legumes, alfalfa and beans separately. During the year, watering was carried out five times, etc. For control, we left 2 hectares of black pyramidal poplar crop, where nothing was done other than weeding. Every 5 years, a census and detailed examination of the entire area of ​​crops was carried out, the results of which are reflected in Table 1.

It should be noted that poplars where alfalfa was sown between rows had relatively more growth, and the foliage was darker green than where beans were sown. Apparently, this is explained by the fact that alfalfa by nature vegetates much longer than beans. In addition, alfalfa has a more powerful root system and more specimens grow per unit area. The alfalfa phytomass remains in place, while the beans are completely removed.

The roots of most poplars have significant vitality. They are extremely capable of forming so-called adventitious buds, from which, under favorable conditions, very fast-growing root shoots develop.

Poplar is of great importance in sanitary, hygienic and balneological terms, because releases more oxygen and phytoncides among deciduous trees. The released phytoncides significantly weaken, and in some cases completely suppress, the effect of pathogenic principles in the environment.

Poplar plantations help clean the air from dust and prevent its further spread. Harmful gases are absorbed simultaneously with dust. The filtering role of plantings is explained by the fact that part of the gases is absorbed during the process of photosynthesis, while the air is enriched with oxygen in greater quantities than many tree species.

This is due to the fact that all poplars vegetate and grow in height during the growing season much longer than other tree species.

Thus, the proposed method makes it possible to determine the sex of trees and increase forest productivity.

Table 1
Productivity of 25-year-old black pyramidal poplar plantations in the Tskhinvali forestry enterprise
Taxation elements	Tree stand age (years)
5	10	15	20	25
1	2	3	4	5	6
Number of trunks per 1 ha	1110	895	643	5008	382
Control	1251	963	735	640	427
Average diameter, cm	8,0	17,2	29,0	37,1	44,4
Control	4,1	9,5	18,8	22,3	30,0
Average height	8,7	16,5	22,3	29,6	35,4
Control	6,0	10,4	15,7	18,5	22,0
Reserve per 1 ha, m 3	72,5	250	386	560	697
Control	40,3	105	186	263	341
Total average annual growth per 1 hectare, m 3	14,5	25	25,7	28	27,9
Control	8,1	10,5	12,4	13,5	13,6

A method for determining the sex of a poplar, including determining external signs during the growing season, characterized in that when flower buds form, they are cut and under a magnifying glass with 10x magnification, the male sex is determined by the filled round yellowish perianths with anthers, and the female sex by their absence.