Mansonia altissima
| Mansonia altissima | ||||||||||||
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| Scientific name | ||||||||||||
| Mansonia altissima | ||||||||||||
| ( A. Chev. ) A. Chev. |
Mansonia altissima is an African deciduous tree of the genus Mansonia in the mallow family (Malvaceae). In the western part of Central Africa , where Mansonia altissima is native, the common names Aprono ( Ghana ), Afon (Ofon), Odo and Urodo ( Nigeria ), and Koul ( Congo ) are also in use. In the German-speaking wood import market, the wood is offered both as Mansonia and Bété.
description
Vegetative characteristics
As a medium-sized, evergreen tree, Mansonia altissima reaches a height of up to 35, according to some information up to 45 m with a mean diameter of 50 to 80 cm. Compared to other Sterculiaceae , the cylindrical trunk grows straight and well-formed and is often knot-free up to a height of 20 m and suitable for timber. Occasionally, narrow buttress roots are formed up to a height of approx. 3.7 m. The relatively small crown consists of horizontally protruding branches. The bark is brown and smooth in young specimens, later pale brown-gray, yellow on the inside, and in older trees it is longitudinally fissured with rounded scales.
The alternate, egg-shaped to obovate or rounded, simple and papery leaves of Mansonia altissima can reach a length of 15–30 m and width of 7–23 cm. The base of the leaf blade is heart-shaped, the tip rounded to pointed or pointed, the edge can be slightly wavy, curved or, especially on young plants, toothed. At the base of the 2–5 cm long petiole sit two, not perennial, triangular stipules . The leaf stalks and the underside of the leaf blade are tomentose, with interspersed star hairs. The nerve is palmate.
The species sheds the foliage from February to early April.
Generative characteristics
The terminal ( zymous ) floriferous and conspicuous inflorescences reach 12 to 15 centimeters in length, they are short and densely hairy. The stalked, hermaphrodite and fragrant single flowers are up to one centimeter long and have a hairy calyx that is about one centimeter long, split open on one side. The five bare petals of the flower are obovate and about 12 millimeters long and 6 millimeters wide. They are colored white. The ten almost seated anthers in a circle and the scaly staminodes sit on an androgynophore about 18 millimeters long. The upper ovary consists of five free, velvety hairy carpels with threadlike styles .
The fruits consist of one to three egg-shaped nuts about 5 millimeters in diameter with a net-like structured surface on which a 5 to 6 centimeter long, paper wing sits on one side.
The flowering period begins in June and ends in August. The fruits are ripe from December to February. The wind-spread fruits are usually found quite close to the mother tree.
Wood
Mansonia altissima has a whitish sapwood approximately 4 cm wide . The color of the heartwood can vary from light to dark brown and purple-black, depending on its provenance and origin, although the differences fade with prolonged exposure to light. The heartwood is partly streaked with matt reddish, purple or gray-green stripes. Due to the violet-black color in places, the wood shows a considerable similarity to that of the North American black walnut tree ( Juglans nigra ) and is therefore erroneously traded in the veneer trade as "African walnut".
Wood anatomy
Mansonia altissima is a diffuse pore , which means that the vessels present are without a specific arrangement. The numerous vessels are in radial groups of mostly two or three pores. In the longitudinal section, these are visible as narrow pore grooves. The growth zones are made clear by the dark latewood zones. There are numerous (9 to 11 per mm), narrow and heterogeneous rays . The width of the wood rays is usually one to three cells, the height about ten to 15 cells. Crystalline deposits of calcium oxalate are found on ray and storage cells . It is a straight grain wood with dense and even growth.
Radial section of Mansonia altissima
Tangential section of Mansonia altissima
Cross section of Mansonia altissima
Occurrence and habitat
The entire Upper Guinea coast from Eastern Liberia to the Ivory Coast , Ghana and Nigeria to the southeast of Cameroon is named as the home regions of Masonia altissima . In places there are also deposits in the northeast of the Congo . The preferred area of Mansonia altissima is the lowlands of the rainforest zones with pronounced dry periods. The single, scattered tree can be found mainly in the transition areas between the evergreen wet forest and the deciduous dry forest.
The semi-evergreen forests that the species prefers grow in regions with around 1,600 millimeters of annual rainfall with a pronounced dry season. In the north it occurs in isolated forest islands within the savannah belt. In some regions, such as Ghana, the species is more common in thinned secondary forests than in undisturbed primary forests. Seeds do not grow on nutrient-rich, well-drained soils; if planted on soil-wet locations, they perish within a few years. The young plants are very needy of light.
Use and properties
Drying takes place quickly and easily. When processing the dry wood, suction devices should be provided, as the wood dust, due to its toxic ingredients, which makes the wood very durable, leads to irritation of the mucous membranes. In parts of the southwestern Ivory Coast, the bark is the main component of a very powerful arrow poison , which is also used in spear traps for large game.
Due to its similarity to the black walnut tree , the wood of Mansonia altissima is often used as a walnut substitute. The wood is also used for the manufacture of musical instruments, especially in piano manufacture. In addition, fittings and interior fittings, high-quality furniture, parquet and micro-veneers (very thin) are made from it. Other types of use are cabinet making and turning.
International trade
Mansonia altissima wood was first exported from Nigeria in the 1930s . Between 1959 and 1970 Nigeria exported around 15,500 m³ of round timber and 800 m³ of sawn timber . The Ivory Coast exported around 131,400 m³ of round timber and 2,700 m³ of sawn timber between 1967 and 1972. In 2000 and 2001, Ghana exported 2,700 m³ sawn timber and 300 m³ round timber. Europe and the United States are considered the main importers.
| Parameter | value | unit |
|---|---|---|
| Bulk density | 0.6-0.7 | g / cm³ |
| Compressive strength | 60 | N / mm² |
| modulus of elasticity | 13,000 | N / mm² |
| tensile strenght | 110-120 | N / mm² |
| Flexural strength | 125 | N / mm² |
| Shrinkage (radial) | 4.0 | % |
| Shrinkage (tangential) | 6.2 | % |
| Shrinkage (volume) | 11.9 | % |
| Cargo weight | 900-950 | kg / m³ |
Source:
Taxonomy
The species was by Auguste Chevalier in 1909 under the basionym Achantia altissima first described and later by himself in 1912 in the genus Mansonia transferred. The genus Mansonia comprises five tropical tree species with a disjoint distribution (consisting of several separate subareas) in West, Central and East Africa , eastern India and the border area between Myanmar and Thailand in Asia.
There are two varieties:
- Mansonia altissima var. Altissima
- Mansonia altissima var. Kamerunica Jacq.-Fél. This is distinguished by smooth young branches.
The demarcation of the second variety under the name Mansonia nymphaeifolia Mildbr. specimens described from Cameroon is unclear.
Individual evidence
- ↑ a b c d e f Klaus-Günther Dahms: African export woods . DRW-Verlags-GmbH, Stuttgart 1968, ISBN 3-87181-321-4 , p. 187-189 .
- ↑ a b Mansonia. Retrieved December 8, 2016 .
- ↑ a b Akindele Akinnagbe: Genetic Variation in Mansonia Altissima A. Chev. and Triplochiton Scleroxylon K. Schum Under Different Regimes of Human Impact in Akure Forest Reserve, Nigeria . Cuvillier Verlag, Göttingen 2008, ISBN 978-3-86727-751-8 .
- ↑ Helmut Gottwald: Handelshölzer: their naming, determination and description . Ferdinand Holzmann Verlag, Hamburg 1958, p. 189 .
- ↑ a b c Andrew Praciak (editor): The CABI Encyclopedia of Forest Trees. CABI Center for Agriculture and Biosciences International, 2013, ISBN 978-1-78064-236-9 , pp. 279-280.
- ↑ a b c d e f g D. Louppe, AA Oteng-Amoako, M.Brink (editors): Plant Resources of Tropical Africa (PROTA). 7 (1): Timbers 1 , PROTA Foundation, Wageningen, Netherlands 2008, pp. 356-360. online with the same text: Mansonia altissima. (No longer available online.) Archived from the original on December 23, 2016 ; Retrieved December 20, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b Terry Porter: Recognize and determine wood. The reference work for practice. (Over 200 types of wood and their use) (= HolzWerken ). 2nd Edition. Vincentz Network, Hannover 2011, ISBN 978-3-86630-950-0 , p. 236 .
- ↑ JPM Brenan: Some Aspects of the Phytogeography of Tropical Africa. In: Annals of the Missouri Botanical Garden. 65 (2), 1978, 437-478.
Web links
- Mansonia altissima at Useful Tropical Plants.