Diospyros crassiflora
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Diospyros crassiflora is a species of the genus Diospyros within the ebony family(Ebenaceae). In the countries of natural origin, the common names African ebony and Ébéne are also used. The designation according to the country of origin, such as Cameroon ebony, is also common.
description
Appearance and leaf
Diospyros crassiflora grows as a medium-sized tree and reaches heights of up to 25 meters. The trunk is cylindrical or grooved, free of knots and has a height of up to 15 meters with a diameter of up to 120 centimeters. Other sources give a height of 15 to 18 meters and a trunk diameter of 60 centimeters. No buttress roots are formed. The black-gray bark has fine longitudinal cracks that flake off in thick scales. The bark of the branches is reddish to gray-brown with longitudinal cracks and the bark of the young branches is bare.
The alternate arranged leaves are divided into petiole and leaf blade. The leaf stalk is up to 1.5 inches long, grooved at the top and almost bare. The simple, thin, leathery, almost bald leaf blade is 10 to 21 centimeters long and 4 to 10 centimeters wide and lanceolate-elliptical to oblong-elliptical with a wedge-shaped to rounded and somewhat asymmetrical blade base, an abruptly pointed upper end and a smooth leaf edge . The upper side of the leaf is dark green, the underside lighter. There is pinnate nerve with five to eight pairs of lateral nerves. Stipules are missing.
Inflorescence and flower
Diospyros crassiflora is dioecious separate sexes ( diocesan ). The lateral, bundled inflorescences are often found on older branches. The male inflorescences contain three to six, the female only one or two flowers.
The almost sessile, functionally unisexual flowers are radial symmetry . The fleshy, pink-red calyx is up to 1 centimeter long and consists of a calyx tube that is only slightly longer than the rarely four, usually five calyx lobes. The four to six pink-white petals are fused to form a 2.5 to 3 centimeter long, ellipsoidal corolla tube that ends in four to six short corolla lobes. The male flowers contain many stamens that are up to 1.5 inches long and have only short stamens; there are rudimentary ovaries. The female flowers include a top permanent, spherical with a diameter of about 5 millimeters, eight to zehnkammerigen ovary ; there are four to five styles and rudimentary stamens present.
Fruit and seeds
The berries are ellipsoidal to obovate and contain up to ten seeds , with a length of about 10 centimeters and a diameter of about 6.5 centimeters . The fruits are sparsely hairy to glabrous and yellowish in color when ripe. The durable calyx, enlarged to a diameter of up to 4 centimeters, envelops the base of the berry. The shiny brown to black seeds are elongated, 5 inches long, 2 inches wide and 1.5 inches thick.
Occurrence and endangerment
Diospyros crassiflora is found in Cameroon , Ghana , Nigeria , the Democratic Republic of the Congo, and the Republic of the Congo . Occurrences in Gabon and the Central African Republic are also described. In Nigeria, the cities of Benin City , Abeokuta and Onitsha are given as occurrences where Diospyros crassiflora is found "in groups or small stands, half a mile or less in extent". The banks of the Niger are also listed as a distribution area.
According to the IUCN Red List of Threatened Species in 1998, the threat to Diospyros crassiflora was given as "endangered"; a new data collection is required.
Taxonomy
The first description of Diospyros crassiflora was in 1873 by William Philip Hiern in A Monograph of the Ebenaceae . Synonyms here are Diospyros ampullacea Gürke , Diospyros evila Pierre ex A. Chev. and Diospyros incarnata Gürke ex De Wild.
use
Wood
Wood description
The heartwood is purple and is clearly different in color from the sapwood . Usually only short heartwood blanks from Diospyros crassiflora are sold on the market. Of the ebony species, Diospyros crassiflora has the blackest wood . It is very dense and hard, with a fine and even structure.
Technical data on wood
The average dry weight is 1030 kg / m³. The grain is predominantly straight to slightly twisted . Diospyros crassiflora shows great shrinkage behavior .
| Parameter | value | unit |
|---|---|---|
| Bulk density | 0.81-1.05 | g / cm³ |
| Compressive strength | 90 | N / mm² |
| tensile strenght | k. A. | N / mm² |
| Flexural strength | 181-200 | N / mm² |
Wood properties
The wood of Diospyros crassiflora is heavy and very impact-resistant. It shows a high compressive strength , whereby it is very rigid and only allows a low deformability. The suitability for steam bending is described as good. Because of the relatively high density, tools dull very quickly and machining is difficult. There is a risk of tearing out and splintering. Editing with the scraper is possible, however. Fine teeth should be preferred when sawing. Gluing is easy to carry out and drilling and nailing should be pre-drilled. It is possible to achieve very high surface qualities. The wood can be air-dried quickly, whereby only small surface cracks can occur as drying errors.
Shelf life and use
The wood of Diospyros crassiflora is very durable and cannot be treated with wood preservatives. Treatment is also not indicated for most uses. Diospyros crassiflora is used as wood for carving and turning, for cutlery handles, bagpipe tuning pipes, door handles and instrument keys. Traditionally, parallel rulers are made from Diospyros crassiflora . Diospyros crassiflora is partially attacked by bark beetles (Scolytinae). In Nigeria, Diospyros crassiflora is described as being termite-resistant .
Wood anatomy
The vessels are arranged with scattered pores and the vessels are without a specific arrangement. Growth zones are not recognizable. The vascular pits are alternate and have a vertical diameter of 3 to 5 µm. There are numerous, very thick-walled fibers with fiber pits. The rays are almost exclusively single-row, consisting of one or rarely two cell types. There are seldom double-row beams. Medullary rays are only visible in a radial longitudinal section. There are crystals in the axial parenchyma, with one crystal per cell.
Health risks
The wood dust from Diospyros crassiflora can cause dermatitis, conjunctivitis , skin irritation and sneezing . The possibility is mentioned that Diospyros crassiflora may act as a skin sensitizer.
swell
Individual evidence
- ↑ a b c d e f g h i Terry Porter: Recognizing and determining wood . 2nd Edition. HolzWerken, Hannover 2011, ISBN 978-3-86630-950-0 , p. 109 .
- ↑ a b c d e f Lemmens, RHMJ, Louppe, D. & Oteng-Amoako, AA: Diospyros crassiflora . (No longer available online.) In: PROTA (Plant Resources of Tropical Africa / Ressources végétales de l'Afrique tropicale), Wageningen, Netherlands. Obeng, EA, 2010, archived from the original on March 24, 2015 ; accessed on January 4, 2014 . 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 c Diospyros crassiflora in the IUCN Red List of Threatened Species 2014.3. Listed by: African Regional Workshop (Conservation & Sustainable Management of Trees, Zimbabwe, July 1996), 1998. Retrieved November 25, 2013.
- ↑ a b Johannes Bärner: Die Nutzholz der Welt 3rd volume . J. Neumann, Neudamm 1943, p. 527 .
- ^ Diospyros crassiflora in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved November 21, 2013.
- ^ Diospyros crassiflora at Tropicos.org. Missouri Botanical Garden, St. Louis. Retrieved November 21, 2013.
- ↑ a b c H. G. Richter & MJ Dallwitz: Diospyros spp. (Black ebony - Africa, Madagascar). In: Commercial Timbers. May 4, 2000, accessed November 14, 2013 .
- ↑ a b c d e f Michael Finger: Ebony, black (Diospyros crassiflora). In: Holzwurm-page, wood with know-how. Retrieved January 4, 2014 .
- ↑ a b c d e f Jaroslav Durst: Handbook of timber; Basics, names, occurrences, appearance, properties and use . Fachbuchverlag Leipzig, Leipzig 1959, p. 191-192 .
