Ailanthus altissima
Tree of heaven ( Ailanthus altissima)
The tree of heaven ( Ailanthus altissima ) is a kind of deciduous tree of the genus Ailanthus from the family of bitter ash plants ( Simaroubaceae ).
- 3.1 Use in China
- 3.2 Use in Europe
- 3.3 Introduction to Europe and spread
- 3.4 The tree of heaven as a town green
Dissemination
Originally the gods tree is native to China and northern Vietnam. Since the mid-18th century, the species was later planted in other parts of Asia, Europe, America, Africa and Australia, where it is considered invasive species. As a result, the tree of heaven spread increasingly, now he is growing wild represented worldwide in all areas with a temperate or Mediterranean climate.
Botanical description
Habitus, age and height
The tree of heaven is a medium sized tree (life-form Phanerophyt ), which on good locations 27 to 30 m can be large in Central Europe. In the Mediterranean region, as well as on poor, dry sites he usually only reaches heights of 18-20 m.
As a pioneer tree he usually does not reach 100 years, however, significantly older trees are known. The oldest in Germany grew in a garden of Pharmacy Arminius in Bad Lippspringe in the Detmold Road 163 The tree reached a circumference of 1.40 m, a height of 35 m and an age of 150 years.
The tree of heaven is considered schnellstwüchsiger tree in Europe. The greatest height growth occurs at 5 to 10 year old trees. After 20 years, the height growth slows markedly. Seedlings can on favorable sites in their germination already be 1-2 meters high. On good sites 20 -year-old trees over 20 m can be high. Particularly strong is the height growth of sprouts which are vegetatively driven from the root ( root sprouts ) or trunk rash that forms numerous after a disturbance of the tribe, eg as a result of Bekämpfungen. Such shoots can be up to 3 m long in a year.
Branches, trunk and crown structure
Young shoots with leaves are hairy and greenish short. Older branches are reddish or brownish and glabrous. The trunk is smooth, has a gray- brown bark and has a diamond-shaped pattern on aged.
The growth of the shoots will not resume from the terminal bud, but of underlying lateral buds. This sympodial growth leads to an irregular crown structure. Typical of the Tree of Heaven is a change in the branching pattern after about 10-15 years. Then the further growth is taken over by one or two now leading side shoots ( monochasiales or dichasiales growth).
The large unpaired leaflets are often forty to ninety centimeters long. Especially in young root sprouts or root rashes they can be long and about one meter. The largest previously known sheet had a length of 1.67 m ( Kowarik & Säumel 2007). A pinnate leaf is formed of 20-30 (maximum 43) oblong- oval leaflets, the number of which varies greatly. At its base, the leaflets to 2-4 glands, which make the leaves of the tree gods unmistakable and have also led to its name " glandular tree of heaven ." These glands are nectaries that secrete sugar and are therefore attended by ants.
The leaves are dark red in bud and usually appear only in May. The leaf fall in autumn starts very late. An autumn color of the leaves does not occur.
Flowers
The species is dioecious getrenntgeschlechtig ( dioecious ), that is, the male and the female flowers are found on different trees. A flower has five petals. Male flowers contain 10 stamens. Although Female flowers can also contain stamens, but they do not contain pollen, so that there is no bi-sexual flowers. The yellowish- green flowers are rispenähnlich arranged, the inflorescence is the type of a double thyrsus. Male inflorescences are larger and have more flowers than female.
The flowers appear in Central Europe usually in July. The smell is strong and is even perceived smelly especially in male flowers as unpleasant. The flowers are visited by honeybees and other insects. The honey of the gods tree has a very tasty, muskatellerartiges flavor, even though he initially does not smell good. In the fresh state it is of a greenish to brownish in color and viscous consistency; it crystallized from fine and lard -like, in this case, the color of honey changed to dirty gray green. The pollen of the gods tree represent a new potential allergen
Fruits
After flowering until September on both sides winged and spirally twisted fruits develop in August with a central seed. The color of the fruit can vary between green, brown and red. The average length of the fruit is 47 mm, the average width of 9 mm. Even 3-5 year old trees can bloom and produce fruit. On a 8 m high tree 650 infructescences were counted with 325,000 individual fruits.
Use and introduction to Europe
Use in China
In China, the leaves to feed the silkworms which must be an Ailanthus or Tree of Heaven moth ( Samia cynthia ) are used that produce usable farms in silk ( " shantung "). In the forest -poor regions at the lower Yellow River, the species belongs to the main timbers. It is particularly suitable for the production of very important in Chinese cuisine steamer. Bark, z.T. also roots and leaves are used in traditional Chinese medicine, this is attested since the Tang Dynasty. The leaves, however, have thereby a weak toxic effect. The bark is attributed to a cooling and astringent effect. Especially frequently it is used in diarrhea. The tree also has a cultural significance. In northern China, the Yellow River it is called spring tree ( ch'un -shu ). The extremely late leaf shoots of the tree here was the sign that the famine of winter and early spring comes to an end.
Use in Europe
Where large stocks of tree gods exist, it is used for honey extraction. The very spicy tree of heaven Honey is a local specialty. A forest use has been proposed in Austria, but is so far not been performed. You would be possible due to the quality of wood.
Introduction to Europe and spread
The first plants arrived in 1740 by the Jesuit Pierre Nicolas d' Incarville to Paris. Both the use as an ornamental plant as well as the attempt to use the tree economically, contributed to its spread. In Vienna, an effort was made to introduce the silkworm as farm animals in Europe with the help of this tree, and thus contributed to a feral population in Vienna. In Berlin, he was already in 1780 cultivated as an ornamental plant. Wild growing trees gods are now common in the inner cities of the larger German cities; However, they appeared only after 1945 reinforced on rubble areas. The invasion biologist Ingo Kowarik attributes this to the fact that before 1945 open areas were relatively rare, and they were too intense maintained to allow the construction of a spontaneous population.
The tree of heaven as a town green
The tree of heaven is relatively resistant to salt, drought and herbicides and tolerated emanating from urban air pollution stress often better than many other city trees. Ailanthus require an annual average temperature of about 9 degrees Celsius and are sensitive to winter frosts. Given its status as an invasive species of tree of heaven should not be planted. About the use of existing populations is controversial, it appears necessary to prevent the further spread uncontrolled, as they threatened by displacement of native species biodiversity of habitats such as skim lawn.
The tree of heaven as a neophyte
The spent hemerochor to Europe ailanthus is the top one hundred most problematic invasive species in Europe expected ( " 100 of the worst" ) ( DAISIE ). Once established, the tree of heaven is only with great effort to remove it because it is unusually resistant to drought, cutting and herbicides. In some states, such as in Austria and Switzerland, the Tree of Heaven is already being actively prevented from spreading, as in Basel, where he is systematically eliminated along the banks of the Rhine. In Hungary, the tree is threatening the communities of the lean and rock turf due to the spread. The species is particularly problematical where the penetrating in poor grassland and open forests, since it provides for an increase in available nitrogen by easily degradable litter. The maquis can be displaced, as on the Italian island of Procida in the Gulf of Naples. The tree can cause considerable damage to infrastructure and increase the burden for the maintenance of the ancient sites and roads in the Mediterranean.
Despite its status among the top 100 of the invasive plant species in Europe, the tree of heaven in Germany has been considered relatively little since its holdings are still largely limited to urban heat islands, such as in Dresden and Berlin. Faced with increasing mean annual temperatures due to global warming generally spread into the surrounding countryside would be possible in the absence of countermeasures. This expansion is, for example, already observed on the outbound from Berlin highways. So far, the species is in Germany outside the cities rare and strikingly along railway lines and major roads such as Highways bound. Even in big cities like Berlin and Vienna is the very common kind in the city center to the outskirts towards increasingly rare (in Berlin from 92.2 % of occupied grids to 3.2 %). In northwestern Germany it is still quite rare, probably due to low heat sum during the vegetation period. This emerges in the Ruhr only occasionally. For North America hold Albright et al. a significant expansion of the distribution is very likely.
Combat the gods tree
Constan - Nava et al. report that the fight against the gods tree in the Mediterranean already high cost, as it rapidly expels after the cut again and forms dense stands. The most effective method is recommended after evaluation of a five -year study, to fell the trees and treat the shoots with glyphosate. In North America, specialized weevils Eucryptorrhynchus brandti been tested to fight the tree of heaven biologically.
Tree of Heaven as insect food
A Pfauenspinnerart whose cocoon is made of silk threads, the Ailanthus is Spinners ( Samia cynthia ). It feeds on the leaves and out of its cocoon can produce a silk that is more durable and less expensive than the usual silk. The Ailanthus - spinner was introduced in several urban areas of the eastern United States as well as in Vienna to establish a silk industry. Time of introduction was in Vienna in 1856; Since 1924, the Ailanthus - spinner in Austria is considered neozoon. However, in its distribution it is to the gods trees and thus bound to over -heated urban areas. Also in the Eastern U.S. will find this Spinner only to the city. The occurrence of Ailanthus - Spinners is an example that an established and widespread neophyte can also drag its insect pests by yourself. In the case of Ailanthus - Spinners man was very much involved in its spread, however.