Красная шелковица: описание, распространение и угрозы исчезновения.

Species of tree

Morus rubra, commonly known as the red mulberry, is a species of mulberry native to eastern and central North America. It is found from Ontario, Minnesota, and Vermont south to southern Florida, and west as far as southeastern South Dakota, Nebraska, Kansas, and central Texas. There have been reports of isolated populations (very likely naturalized) in New Mexico, Idaho, and British Columbia. Common in the United States, it is listed as an endangered species in Canada, and is susceptible to hybridization with the invasive white mulberry (M. alba), introduced from Asia.

Red mulberry is a small to medium sized deciduous tree, growing to tall, rarely , with a trunk up to in diameter. It can live up to 125 years. The leaves are alternate, long (rarely to ) and broad (about twice as big as the white mulberry's leaves), The leaf petiole exudes milky sap when severed. The leaves turn yellow in autumn. The flowers are relatively inconspicuous: small, yellowish green or reddish green and opening as leaves emerge. Male and female flowers are usually on separate trees although they may occur on the same tree. The fruit is a compound cluster of several small achenes surrounded by a fleshy calyx, similar in appearance to a blackberry, long. It is initially pale green, ripening to red or dark purple. Red mulberry is hardy to subzero temperatures, relatively hardy to drought, pollution, and poor soil, though the white mulberry is hardier. The berries are widely sought after by birds in spring and early summer in North America; as many as 31 species of birds have been recorded visiting a fruiting tree in Arkansas. The red mulberry is pollinated by the wind.

The red mulberry plant is native to the United States. M. rubra occurs from the Atlantic coast to the eastern edge of the Great Plains, south to southern Florida and north to southwestern Ontario in Canada. The native red mulberry can be mostly found in riparian areas, and is considered rare and threatened in many areas including northeastern United States and southeastern Canada. The morphologically similar M. alba is potentially posing a threat to the existence of M. rubra because of the rapid range expansion, aggressive growth patterns, and reproductive advantages over M. rubra. The red mulberry is currently considered endangered in Canada, and in the USA, the states of Connecticut and Massachusetts as well as threatened in Michigan and Vermont. The first English colonists to explore eastern Virginia in 1607 mentioned the abundance of both mulberry trees and their fruit, which was eaten (sometimes boiled) by the native Powhatan tribes. Today, mulberries are eaten raw, used in the fillings of pastries, and fermented into wine. They are also used for marmalades, liquors, natural dyes, and cosmetics. The berries are not commercially sold because they have very short “shelf lives” and pack/ship very poorly. The wood may be dried and used for smoking meats with a flavour that is mild and sweet. It is also used for fenceposts because the heartwood is relatively durable. Other uses of the wood include farm implements, cooperage, furniture, interior finish, and caskets.

Some Native American tribes used an infusion of the bark as a laxative or purgative. Infusions of the root were used to treat weakness and urinary ailments. The sap was applied to the skin to treat ringworm. Documentations of the use of red mulberry go back to 1500 by the De Soto expedition, which recorded the consumption of dried fruits by the indigenous Muskogee peoples. There were diverse uses of mulberry in different indigenous cultures. Among them, the Cherokee mixed cornmeal and sugar to the berries, to make sweet dumplings. Later on, European settlers also used the mulberry fruits to make pies or preserves. The trees were also important as a source of livestock feed and wood for furniture or boats.

In an early stage, pruning is necessary to make the red mulberry tree develop a sturdy framework. Afterwards, the pruning requirements of the red mulberry involve mainly removing dead or overcrowded wood. To keep the tree in a tidy form, it is suggested to choose a few main branches and cut the laterals to six leaves in July. This allows the spurs to develop near the main branches. However, the red mulberry tree tends to bleed after pruning, so pruning should be reduced to a minimum and should be conducted when the tree is dormant, as the bleeding is less severe then. Removing branches of more than 2 diameters should be absolutely avoided. In the first year of a red mulberry's lifetime, a sufficient water supply is critical for the development of the root system. Young mulberry trees should be watered thoroughly twice a week if growing on light soils and once a week if growing on clay soils. Later, the red mulberry is drought tolerant, although under water scarcity it may drop its fruits too early which results in berry yield losses. Thus, for berry production, irrigation is recommended under dry conditions. Mulberry trees thrive with little to no fertilizer. Fertilizing more than twice a year should be avoided and fertilizing later than July may lead to freeze damage. An NPK value of 10 10 10 is targeted and depending on the available nutrients in the soil, other nutrients like iron should be added. Usually, the red mulberry is free from pests and diseases but in some areas the “popcorn disease” may occur. In that case, infected fruits should be collected and burned, to prevent the pathogens population to reproduce and survive for the next season.

Mulberry grows in various climatic conditions and can be found in climates between temperate and tropical. Red mulberry plants require a total annual rainfall of and are adapted to altitudes of up to 800 msl. The native environment of red mulberry most often consists of moist forests, thickets on the floodplains, moist hillsides and river valleys. It can tolerate short periods of flooding and can tolerate temperatures as low as 36 °C ( 33 °F). Optimal growing temperatures are between At least 140 frost free days a year are required. Normally, the tree grows in full sun, but growth is also possible in partial shading. Red mulberry is also drought tolerant. The plants prefer deep, well drained soils that range from loamy to clayey and have a high moisture holding capacity. Mulberry wood has the same quality as oak, which can be sold for 90 150 euro per m3. Nevertheless, to achieve a quantity of 1m3, we should have to take down the whole tree, which can be counterproductive in the case of fruit production. Nevertheless, the wood from the trimming can still be used as firewood and the biggest parts for furniture or turned objects. An additional yield of 8–12 tons/acre/year (20–30 tons/hectare/year) can be achieved with the littler parts and the leaves which serve as forage. Only 2 to 3 years after whip cultivar plantation, the tree should already start to fruit. The yields of fruits should reach 3 to 5 kg (per tree per year) on the first years until 300 kg for a mature tree.

In 2015, almost 3.4 million pounds of frozen mulberries were imported to the US – a market value of 2.6 million US Dollars. The demand for the fruit is still rising and the prices are high. This constitutes a great opportunity for mulberry producers.

Fresh mulberries are mainly water. Per 100g, they provide 1.2g protein and 0.85g fat. Dried mulberries, which is the most consumed form, contain 70g carbs, 14g fibers, 12g proteins and 3g fats per 100g. Mulberries are rich in vitamin C, calcium, iron and potassium.