Alder - one of the most common plants in temperate zones. It is used in construction and traditional medicine. But this tree can often be confused with a birch tree, which also has earrings. Therefore, it is important to understand what kind of alder tree it is and why it is given such a preference.
Botanical description
Alder is a bichromatic plant, a close relative of birch. This genus includes both shrubs and trees, so scientists have a large number of plant species and subspecies. Typical species is black alder (Alnus glutinosa).
Wilha, as the plant is also called, is a deciduous tree that can adapt to different habitats. The leaves of the alder are painted in many shades of green, cuttings and serrated at the edges, and their shape depends on the life form. 
An interesting feature is the cells of the epidermis, a slight pubescence, which is on the branches, leaves and buds. This feature helps in the life of the plant, but does not perform the function of protection against pests.
The plant is often described as a "tree with earrings." This is due to the fact that at the ends of the shoots spike inflorescence grows. It is in them that pollen is formed. The ovules are in small spikelets. The tree has a fruit - a small nutlet.
Habitat
The tree is distributed in areas that fall into a temperate zone. The habitat also depends on the life form of the plant. Therefore, it can be found even in the mountains of South America.
Most often, alder grows in swampy soils in forests. Its habitat extends to the tundra, which are located in the subarctic climate zone. 
Your site will also be decorated with such ornamental trees as: red oak, arbutus, holly, red maple, sea buckthorn.
Popular species
Any of us may have different views of how an alder looks. After all, its type depends on the place of growth. The genus has up to 40 species. The main difference between the trees is the growth and leaves, so let's take a closer look at the photos of the most popular representatives of the Alder genus.
Italian
In the wild, it grows in southern Italy and Albania. The tree is unpretentious to the soil, but the habitat is usually located near the water. "Italian" reaches 15-20 meters in height (less often 25-28 m), the trunk diameter is not more than 1 m.
This species is often confused with cardiac alder. But they are distinguished, firstly, by the name (Alnus cordata - Italian (heart-shaped), Alnus subcordata - heart-leaved); secondly, habitat. 
The leaves on the Italian alder are dense, smooth and can hold until December, have an oval shape and are up to 12 cm long, very similar to cherry leaves and apricots.
Solid
This shrub reaches 3 m in height. Habitat is an island in the Japanese archipelago - Kyushu. Wind resistant, serrated leaves, oblong to 12 cm in length. The branches are thin and flexible, sometimes with a gray coating.
Earrings often paired up to 7 cm. It blooms from March. The plant gets on well in a humid climate. Wood is tougher than other species. 
Black
Black is a type species of the genus. Also known as European due to habitat. Young leaves are sticky, so the name "sticky" is also found. The tree can have two trunks, reaches a height of 35 m.
The crown is not thick, but at the same time volumetric (12 m in diameter). The trunk is up to 1 m in diameter and has a black bark. Flowering occurs usually in April. A light tree, well tolerated by the absence of organs responsible for the consumption of moisture.
If black alder grows in lowland swamps, then alder swamps can form. 
Visloplenaya
In the wild, this type of tree grows in China. But now it can be found in many parks of England. This tree is distinguished by its height (up to 40 m) and lowered branches. The leaves are long and narrow, earrings are solitary and located in the axils of the leaves.
Each of the plant species can be affected by fungi, and the fruit and varicella - is no exception. The marsupial fungi infect female catkins and can cause their growth. Some species of the Tarfina genus form "witch brooms" - a cluster of crowns inside, usually similar to a nest.
Did you know? In ancient times in Scandinavia, they believed in such a legend: a woman was made of alder, and a man was made of ash.
Gray
Gray Alder is found throughout Europe, North America and Asia Minor. In the wild, it grows rapidly, bears fruit once a year, but abundantly, seeds are carried by wind or water. Often grows in pair with black alder near the water.
It is also common in Siberia, along with alder fluffy. Perennial plant is average in height (20 m) with a relatively thin stem (up to 50 cm in diameter). The tree grows in sunny areas, frost-resistant and withstands strong winds due to the flexibility of the branches.
The leaves are toothed, rough, oval and up to 10 cm long. Gray Alder tolerates stagnant water in the soil. On sandy and sandy soils not found due to low acidity and humidity. 
Japanese
The Japanese plant species lives on the entire east coast of Asia. Differs in its olive-colored branches. Height is standard (up to 25 m). Crohn thick, rounded. The leaves are rarely toothed, smooth and not more than 12 cm in length.
Female inflorescences - up to 8 pieces at the end of brushes. Due to the fact that the leaves are kept until the first frost is popular in landscape design. 
Seaside
One of the shrubs, but can reach the height of the tree. The description of this type does not differ from the typical one. However, the habitat includes only the states of North America. The crown is not thick, the trunk is thin and flexible, sometimes up to 10 m tall.
Important! If you want to plant this tree in your area, then remember that it needs more water and fertilizer than the rest of the trees.
Heartworm
Serdselistnuyu can be found in Iran and Azerbaijan. This species does not tolerate winter. There are no organs in the cardiovascular structure that limit the consumption of moisture. That is why the plant is found on wetlands.
The leaves are dense and slightly rounded. Only those forests where the heart-leaved alder grows can be located in the river valley. 
Green
This species is found in both temperate and subarctic climates. Shrub fast-growing with a dense crown. Easily adapts to any habitat conditions. It is distinguished by its frost resistance, because it grows even in the Arctic.
Green alder is often called the transitional stage between birch and alder. After all, this form also assumes the vital form of a tree (in the Far East). Stamens earrings often paired.
The leaves are toothed, slightly rough, dark green in color. In the tundra, green alder can bloom even in July and August.
Did you know? The bark and leaves of a perennial plant were used for dyeing animal skins.
Plant uses
The variety of Wilha species distributed throughout the Northern Hemisphere allows the plant to be used in many areas. After all, the tree is grown fairly quickly and even in the wild aggressively occupies large areas.
The alder includes tannins. Thanks to the flexibility of the trunk, the wood is soft and easy to process.
In folk medicine
The bark and leaves of the tree are endowed with astringents. Therefore, a moistened sheet of black alder can be applied to the wound so that it heals faster. Also, the wound can be disinfected with vodka infusion of cones or earrings.
Infusions of plant earrings help with constipation. Using infusions of flowers, plucked at the very beginning of flowering, you can get rid of the diathesis in children. A decoction of bark helps to cope with pain in the stomach.
To do this, brew 15 g of bark with one glass of boiling water. Then let cool and strain. Take for several days 3-4 times a day. It will be enough for 1 tablespoon at a time. 
But remember that treating the alder may not always help or will only eliminate the symptoms. Therefore, seek qualified medical assistance.
In landscape design
In landscape design it is customary to use shrubs at the expense of their decorativeness. Alder green - the most popular species that is found on sites. After all, it easily gets acclimatized to various conditions, especially overmoistened soils.
The difficulty of using in landscape design is only in the inability to buy seedlings or tree seeds. Therefore, the search for a suitable type of plant can take a long time.
Nevertheless, the alder fully justifies all the forces you have spent, not only with its decorative appearance, but also with unpretentious care. Perennial planted as plants, tapeworms or hedges.
For hedges are also excellent: forsythia, privet, yew, turnberry barberry, wild roseberry, thuja, turn, boxwood, hawthorn.
Important! Do not rush to completely remove the wilha leaves in autumn. After all, they are rich in nitrogen. It will be enough to scrape them around the tree and let it go.
In industry
Wood is considered soft and light for the manufacture of any items. It has a uniform structure and does not crack when screwing in the screws. It has high strength when interacting with water, therefore it used to be used in the manufacture of wells, but now barrels are made of alder.
But most often its wood is used in the furniture industry. Also, the bark of the tree is used to produce dye.
So, the alder is a useful tree. Planting in your plot, you only need to take care of the constant watering of the tree. Green is not afraid of low temperatures, which can not be said about sea alder. 
Therefore, carefully select the type of tree for your climatic conditions. Do not forget that at least twice a year it is necessary to carry out the prevention of plant diseases. Indeed, because of its natural habitat, the tree is prone to parasitic fungi.
