Argan tree
| Argan tree | ||||||||||||
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Argan tree ( Argania spinosa ) |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Argania | ||||||||||||
| Rom. & Schult. | ||||||||||||
| Scientific name of the species | ||||||||||||
| Argania spinosa | ||||||||||||
| ( L. ) Skeels |
The argan tree or the argania ( Argania spinosa (L.) Skeels , Syn . : Sideroxylon spinosum L. , Argania sideroxylon Roem. & Schult. , Elaeodendron argan Retz. ) Is the only plant species of the monotypic genus Argania that belongs to the sapote family ( Sapotaceae) belongs.
origin
The argan tree is endemic in Morocco , Algeria , Western Sahara and Mauritania , and can thrive at altitudes of up to 1,300 meters. Even if the argan forests look wild and bushy, every tree has its owner to this day, who strictly ensures that no stranger picks up the fruits that are ready to be harvested.
The argan tree is also considered a tertiary relic . It is said to have been growing in Morocco for 80 million years; In the Tertiary it probably covered large areas in North Africa and southern Europe, in the Quaternary its range shrank to a few areas in southern Morocco, Algeria and northern Mauritania due to the climatic cooling . In the 1930s, the botanist Louis Emberger described several locations in the Fôret d'Arganie in Mauritania, where the plant was formative for the character of the landscape. Today it almost only grows on approx. 820,000 hectares in southwestern Morocco - an area that was declared a biosphere reserve by UNESCO in 1998 together with other areas ; The centuries-old knowledge and practices of using the tree and its fruits were recognized as Intangible Cultural Heritage of Humanity in November 2014 .
description
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The argan tree is a thorny , drought-resistant and woody, evergreen plant of medium size, with heights of up to 8-12 m, more rarely up to 20 m. For the relatively low trunk, the tree has a widely spreading, dense crown with a diameter of up to over 14 m and a circumference of sometimes more than 50 m, the branches of which partly lean down to the ground, where they are, however, quickly eaten by goats . The trunk diameter can be 1 m or more. The roots of the tree reach down to a depth of about 30 m. The argan tree is able to withstand extreme drought and high temperatures of over 50 ° C. In summer and in dry seasons it loses part of its leaves. It is also called "ironwood tree" (like many other tree species) because of its hard wood. The argan tree has a life expectancy of 150 to 400 years. It has a characteristic, rough, reticulate and cube-shaped "snake skin" bark.
It has narrow and elongated or elliptical to obovate, lanceolate and thick, waxy, simple leaves that appear mostly in groups. The small, leathery, mostly almost sessile to short stalked leaves are entire, hairless and about 2–4 cm long and 1 cm wide. They are usually rounded or, more rarely, pointed and appear axillary next to the pointed thorns.
The seated, small, hermaphrodite, fragrant flowers are five to six-fold and yellow-green with a double flower envelope . They appear axillary and individually or in small groups. There are two brownish wrapper sheets . The round sepals are finely haired and yellowish. The short petals are hood-shaped, the antipetal stamens are protruding, in between there are just as many reduced and pointed staminodes . The hairy and draft tube ovary is upper constant with a relatively short conical stylus .
The egg-shaped to ellipsoidal, partly pointed, about 2–4 cm long and 1.5–3 cm wide berries are hard with a leathery, rubbery, thick and bitter skin. When ripe they are yellowish to orange, reddish with a fragrant pericarp . The egg-shaped, smooth, light brownish and almond-sized, very hard, false stone core (nut) consists of a single seed or up to four seeds that have grown together. These each contain a whitish, flattened and elliptical seed core (platelets), which is about the size of a large sunflower seed. The oil is then extracted from these “seed platelets”.
The first fruits can be expected after five years, but the greatest yield is only achieved between the ages of 50 and 60 years. The fruits of the argan tree do not ripen until June or July of the next year in a so-called "annual cycle" and have bitter flesh. In good years, a tree can bear several generations of flowers and fruits at the same time. The fruits are about the size of dates and look similar to them when dry. When unripe, the argan fruit looks like a mixture of olive and yellow plum, but is morphologically a berry.
use
In Morocco, the argania has been cultivated for oil production for centuries, although in earlier times it was left to nature itself to provide for offspring; State-financed (re) afforestation programs have only been in place since the 1980s. The bush-like argan forests also help to halt desertification .
Lumber
Especially in the tree-poor regions of the western Anti-Atlas , the crooked but extremely durable branches of the argan tree were used in earlier times as timber in the storage castles ( agadirs ) or houses ( tighremts ) of the Berbers - placed next to each other or interlocked like wickerwork, they served above one supporting substructure made of palm trunks as an intermediate zone between the reed and tamped earth ceiling and the ramp-like staircase.
The argan wood is still used today in the restoration of the Agadire, which began tentatively.
Argan oil
The dried out fruits are traditionally picked from the ground by hand in summer (depending on the altitude and the resulting ripening time in July / August / September), as they cannot be knocked down from the tree because of the many thorns and dense branches. In plantations, however, there is also mechanical harvesting with the help of a vibrating shaker; the fruits then fall into a laid net and can easily be picked up and filled into sacks. These are stored in the houses or in the Agadirs until further processing.
Processing begins with the removal of the dry pulp; then the extremely hard kernels are cracked open by hand with the help of two stones in order to detach the seed flakes they contain. The dry pulp and the peel of the kernels are mostly used as fuel in the kitchen stove. The seed flakes are roasted over low heat and then ground in a stone or metal mill; the resulting pulp is kneaded with the addition of a little lukewarm water until the oil separates.
About 30 kg of fruit (about 4.5 kg of seeds) are needed to produce one liter of argan oil. It is usually not heated; H. used for frying, stewing or cooking, but traditionally serves as a side dish with all meals of the day; it has only recently been served as a salad oil.
literature
- Wolfgang Franke : crop science. Revised by Reinhard Lieberei and Christoph Reisdorff, 7th, completely revised and expanded edition, Thieme, Stuttgart a. a. 2007, ISBN 978-3-13-530407-6 .
- Marilena Idžojtić: Dendrology. Academic Press, 2019, ISBN 978-0-444-64175-5 , p. 82.
Web links
- Argan Tree - Information on seeds at Kew Seed Information Database.
- Argania spinosa . In: S. Dressler, M. Schmidt, G. Zizka (Eds.): African plants - A Photo Guide. Senckenberg, Frankfurt / Main 2014.
- Argania spinosa at plantsystematics.org.
- Argania spinosa at Useful Tropical Plants.
Individual evidence
- ↑ Rafaël Govaerts (Ed.): Sideroxylon spinosum. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved June 4, 2020.
- ↑ Recognition as a biosphere reserve (English) .
- ↑ Inclusion in the List of the Intangible Cultural Heritage of Humanity (English) .
- ^ A b Marie-Pierre Ruas, M. Tengberg, Ahmed S. Ettahiri et al .: Archaeobotanical research at the medieval fortified site of Îgîlîz (Anti-Atlas, Morocco) with particular reference to the exploitation of the argan tree. In: Vegetation History and Archaeobotany. 20 (5), 2011, pp. 419-433, doi : 10.1007 / s00334-011-0306-2 .
- ↑ Argania spinosa on plantsystematics.org, accessed February 22, 2018.
- ↑ Gerd Krüssmann : Manual of Cultivated Broad-leaved Trees & Shrubs. Vol. I: A-D , Timber Press, 1984, ISBN 978-0-917304-78-1 , p. 170.
- ↑ Argania spinosa in the Flora of Iberica (illustration).
- ^ Argan tree (Argania spinosa) in the Encyclopedia of Life . Retrieved February 22, 2018.
- ↑ Dieter Nill, Elke Böhnert: Value chains for maintaining biological diversity for agriculture and food - potatoes from the Andes, Ethiopian coffee, argan oil from Morocco and grasscutters in West Africa, p. 38, German Society for Technical Cooperation (GTZ), May 2006; accessed in February 2017