Afzelia bipindensis
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Wood from Afzelia bipindensis from the collection of the Thünen Institute for Wood Research Hamburg |
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| Afzelia bipindensis | ||||||||||||
| Harms |
Afzelia bipindensis is a species of plant of the genus Afzelia in the subfamily Carob Family (Caesalpinioideae) within the legume family (Fabaceae). It comes from tropical Africa .
Trafficking and exposure
Afzelia bella is a synonym and is traded on the international market primarily under the name "Doussié", but also as Apa or Lingue . With the trade name Afzelia (Doussié) the woods of all botanical species of the genus Afzelia occurring in Africa are summarized.
The wood is characterized by the excellent mechanical and physical properties of an attractive import wood with a large value. This led to a strong deforestation and use, making this kind on the Red List of IUCN in the category VU (vulnerable), so as endangered, are listed.
description
Appearance and leaf
Afzelia bipindensis grows as a semi-evergreen, large tree that can reach heights of up to 40 meters. The trunk, which is cylindrical at chest height diameters of up to over 1.4 meters, can be knot-free up to heights of 25 meters. However, these values are highly dependent on the location. It can occasionally buttress roots occur up to a height of 1.5 meters or the trunk is corrugated. The bark is yellow to red-brown.
The alternate leaves are pinnate in pairs. There are 8–16 short-stalked, ovate or elliptical to elongated leaflets. They are entire, glabrous and about up to 10-16 inches long and up to 4-6 inches wide. The leaflet stalks are sometimes twisted and the tip is rounded to briefly pointed, rarely tailed. The overgrown stipules are permanent in the lower part, the upper part is sloping.
Inflorescence and flower
The terminal or lateral, up to 18 centimeters long paniculate inflorescences are hairy short. The flower stalk is 0.5 to 1 centimeter long. The small, sloping bracts are 0.5 to 1 cm long and about 0.5 cm wide. The hermaphroditic flowers with a double envelope are zygomorphic and give off a sweet smell and hardly differ in their shape and structure from the other species of the genus Afzelia . There is a 2–4 centimeter long and funnel-shaped flower cup . There are four unequal, green and externally hairy sepals and only one large, nailed petal . The petal has a long, creasingly folded nail and a two-lobed plate with frilly edges . The plate is white to pink and has a reddish-purple color in the center. There are seven very long and fertile stamens and two short staminodes. The medium-sized, pedunculated and elongated, slightly hairy ovary has a long stylus with smaller capitate scar .
Fruit and seeds
When ripe, the legumes, which are dark brown to black, lignified, flat and somewhat kidney-shaped, have a length of up to 11-19 centimeters and a width of up to 6-8 centimeters and contain up to 15 seeds. The 2.5–4 centimeters long, black and egg-shaped seeds have a bilobed and orange-reddish aril .
Occurrence
The area of origin extends from Central Africa, such as Angola , Uganda and Congo, to West Africa , for example Nigeria and Ghana . Most of the doussie is exported from Cameroon . In 2008, 6100 m³ of Doussié from Cameroon were sold. Afzelia bipindensis grows up to an altitude of 900 m in both primary and secondary forests .
Wood description
Macroscopically
The sapwood of the wood is yellowish-gray in color and, depending on the age, is between three and ten centimeters wide. The core, in turn, shows a reddish brown to light brown color when fresh and is thus strongly separated from the sapwood area. Over time, the heartwood darkens to a copper-brown to dark red-brown color. Due to natural, waxy ingredients, it can happen that small areas do not darken or not so much, which creates a blotchy appearance and thus deteriorates the visual quality. Otherwise the wood can be described as decorative.
The course of the wood fibers shows a pronounced alternating twist . The growth zones are partially clearly visible in the wood image or only separated from one another by a fine marginal axial parenchyma, which serves as storage tissue. The large vessels are scattered pore, in short rows, disordered in the wood. The vessels are surrounded by an aliform, i.e. diamond-shaped, axial parenchyma, which is clearly visible on the longitudinal surfaces of the wood.
Microscopic
The wood rays are very narrow and often less than 1 mm high and therefore rather inconspicuous on the three cut surfaces.
- Afzelia bipindensis - microscopic images
cross-section
Radial section
Tangential cut
use
The species Afzelia bipindensis has durability class 1 according to DIN EN 350-2 and is therefore considered to be very durable. It also shows a high resistance to wood-destroying fungi and insects, so that no protective measures have to be taken against them. This is due to the derivatives and kaempferol embedded in pores , which have an antibacterial and fungicidal effect. For example, pore grooves with a white to yellowish content are visible on the longitudinal surfaces of the wood.
Machining
Due to the great hardness, carbide-tipped tools must be used for processing the wood in order to achieve a longer service life. A pre-drilling is also necessary for the use of screws and nails. The dust generated during processing can irritate the skin and respiratory tract. Therefore, an exhaust system and the use of breathing masks are recommended.
The surface treatment of the wood serves only to maintain the color and to repel moisture, whereby the paint must be applied up to three times for a top layer. Due to the structure of the wood, it is difficult to soak or stain. The bondability is classified here as good to medium. The optimal wood moisture for gluing and painting is u = 14%.
Drying
The drying process is slow and should therefore be carried out gently. Thus drying does not lead to drying damage or cracking. This is especially true for woods with an irregular grain. The wood remains very dimensionally stable during the drying process.
use
The high durability makes Doussie particularly suitable for outdoor use with or without ground contact. Examples include windows, doors, garden furniture and winter gardens. Due to its good mechanical and physical properties, the wood is also used as construction wood or in interior work, especially where there are high frictional forces. So it is well suited for parquet floors, stairs and racing bike tracks. It is even possible to use it for containers for chemical substances. When wet, however, there is a risk of discoloration on, for example, textiles.
Physical Properties
The following values are taken from DIN standard 68364:
| Bulk density , ρ | 0.8 | g / cm³ |
| Young's modulus , E air-dry, parallel to the grain | 13500 | N / mm² |
| Flexural strength , air dry | 115 | N / mm² |
| Compressive strength , air dry | 70 | N / mm² |
| Tensile strength , air dry | 120 | N / mm² |
| Shear Strength , Air Dry | 12.5 | N / mm² |
Replacement woods
The remaining species of the genus Afzelia are to be mentioned as possible substitute woods, which are similar in color and properties , as they largely show an almost identical structure. Other replacement woods are, for example, Jatoba , Merbau or Iroko .
literature
- Klaus-Günther Dahms: Atlas of tropical woods: Africa. Volume 1, 1990, in Association Internationale Technique des Bois Tropicaux.
- Klaus-Günther Dahms: Small wood dictionary . 2nd Edition. Wegra-Verlagsgesellschaft, Stuttgart 1978, ISBN 3-921546-03-6 .
Individual evidence
- ↑ a b c d e Klaus-Günther Dahms: Small wood dictionary . 2nd Edition. Wegra-Verlagsgesellschaft, Stuttgart 1978, ISBN 3-921546-03-6 .
- ↑ Rudi Wagenführ: wooden atlas. 6th edition, Carl Hanser Verlag, 2006, ISBN 978-3-446-40649-0 .
- ↑ Klaus-Günther Dahms: Atlas of tropical woods. Volume 1, 1990, in Association Internationale Technique des Bois Tropicaux.
- ↑ DIN 68364: 2003-05
Web links
- Afzelia bipindensis at Useful Tropical Plants.
- Data sheet from Prota4u . Retrieved May 14, 2019.
- Data sheet made of GD wood . Retrieved May 14, 2019.
- Data sheet from material archive . Retrieved January 9, 2014.
- Afzelia bipindensis in the endangered Red List species the IUCN 2014 Posted by: African Regional Workshop (Conservation & Sustainable Management of Trees, Zimbabwe, July 1996), 1998. Accessed January 9, 2015.
- Data sheet from Global Plants . Retrieved January 15, 2015.