EMIEN (Alstonia boonei)
Trade Name
Emien
Scientific Name
Alstonia boonei De Wild.
Family
APOCYNACEAE
Common Names
alstonia (United Kingdom); Ekuk (Gabon); Ekouk (Equatorial Guinea); Ekuk (Cameroon); Kauwi (Sierra Leone); Kaiwi (Sierra Leone); Kanja (Cameroon); Bokuk (Cameroon); Awun (Nigeria); Ahun (Nigeria); Emien (Côte d`Ivoire); Mujua (Uganda); Stoolwood (United Kingdom); Patternwood (United Kingdom); Alstonia (Uganda); Mujwa (Uganda); Akuka (Zaire); Tsongati (Congo); Ekuk (Equatorial Guinea); Ekouk (Gabon); Ekouk (Cameroon); Sindru (Ghana)
Scientific Name Synonyms
Alstonia congensis Engl.; Alstonia congensis var. glabrata Hutch. & Dalziel
Description Of The Tree
Botanical Description
The tree reaches a height of 43 m. The bole is usually cylindrical and clear to 26 m in length. Trunk diameter attains 70 to 130 cm over a deeply fluted and buttressed base.
Natural Habitat
Alstonia boonei is reportedly abundant in the humid forests of Cameroon.
Natural Distribution
Widely distributed throughout West and Central Africa.
Wood Identification
Anatomic Description Of Wood
Wood diffuse porous. Vessels in radial multiples of 4 or more common. Tangential diameter of vessel lumina 150 to 200 micras (medium). Tyloses thin walled. Vessels per mm2 less than 6 (rare). Simple perforation plates. Vessel-ray pits similar to intervessel pit Axial parenchyma in continuous tangential lines or fine bands. Non-crystals in axial parenchyma cells. Prismatic crystals in short chains in chambered axial parenchyma cells. 5 to 8 cells per parenchyma strand. Axial parenchyma in narrow bands on lines up to 4 to 10 rays per mm (medium). Rays non-storied. Rays 1 to 4 seriate. Heterogeneous rays and/or multiseriate heterogeneous rays. Non-septate fibers. Fibers with distinctly bordered pits. Fibers with vestured pits.
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Wood Macro Photo Tangential Plane
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Wood Micro Photo Of Transversal Section
Availability
Cites Status
Unrestricted
General Wood Description
Color
The heartwood is white to yellowish white, it is not demarcated. The silver figure is fine (barely visible).
COLOR INDEX (1=Black, 7=Light yellow,white)
6
Grain
Straight; grain has no particular influence on drying, machining and finishing qualities.
Texture
Texture of this species is reported to vary from fine to medium.
Luster
The wood luster is reported to be rather low.
Natural Durability
Not durable; important risks of decay attacks at any processing step, from logs up to final products. It must receive preservative treatment. Sensible to termites attack. Heartwood is sensible to Lyctus attacks.
Natural durability index (1= Very high durability, 7=Vey low durability)
5
Internal Growth Stresses
Residual growth stresses are absent.
Resistance To Impregnation
Easy to treat with a full penetration of the preservative products using vacuum-pressure method.
Wood Physical Properties
Basic Density or Specific Gravity (O.D. weight/vol. green) (g/cm³)
0.34
Air-dry Density (Weight and volume at 12%MC) (g/cm³)
0.36
Total shrinkage Tangential (Saturated to 0%MC) (%)
5.2
Total shrinkage Radial (Saturated to 0%MC) (%)
3.8
Drying Defects
Ease of Drying: Drying is rapid. Drying Defects: It is prone to warping, some checking is also reported. Risk of collapse and caseharden.
Recommended Dry Kiln Schedule
FR-2
Dimensional stability ratio (Total Tangential Shrinkage %/Total Radial Shrinkage %)
1.4
Wood Chemical Properties
Wood Mechanical Properties
Bending Strength (MOR),12%MC (kgf/cm²)
434
Stiffness (MOE) 12%MC (kgf/cm²)
82458
Compression parallel to fiber 12%MC (kgf/cm²)
273
Compression perpendicular to fiber 12%MC (kgf/cm²)
28
Shear strength radial 12%MC (kgf/cm²)
49
Janka hardness (side) 12%MC (kgf)
153
Janka hardness (end grain) 12%MC (kgf)
235
Workability
Sawing
It is easy to saw.
Rotary Veneer Cutting
Suitable for peeling without treatment.
Sliced Veneer
Suitable for peeling without treatment.
Blunting Effect
Slight blunting effect; ordinary tools can be used for sawing and machining.
Machining
Machining of this species is reportedly easy.
Planing
Easy; no particular problems.
Moulding
Moderately easy; tools must be cautiously sharpened.
Boring
Moderately easy; tools must be cautiously sharpened.
Mortising
Moderately easy; tools must be cautiously sharpened.
Nailing
Easy to perform but low nails holding.
Gluing
Glues well if basic gluing technical rules are followed.
Sanding
Particular care is needed to avoid woolly aspect of the surface.
Polishing
Can be polished without surface preparation.
Steam Bending
Steam bending is difficult.
Response To Hand Tools
No particular problems.
REFERENCED USES
End Uses Summary
HOUSING GENERAL, boards, frames, panelling, fittings, FURNITURE AND CABINETS, common furniture, PLYWOOD AND VENEER, cores, PACKING, light packing, pallets, OTHER AND MUSICAL INSTRUMENTS, pencil, matches, door core, coffin, moldings
General Housing
- 10 - Silica in Timbers
Boards
- 13 - Dry kiln schedules for commercial woods. Temperate and tropical. Section III. Latin American (Mexico, Central, and South America) Woods–Conventional Temperatures
Frames
- 16 - Woods of the World
Paneling
- 18 - W3TROPICOS Missouri Botanical Garden
Fittings
- 19 - Silica in Timbers
Furniture Cabinets
- 21 - Tropical timbers of the world. Part III-Southeast Asian and Oceanian Species.
Furniture, Common
- 23 - Handbook of Hardwoods
Panels, Veneers
- 25 - Directory of Timber Trade Malaysia
Cores
- 27 - Embassy of Brazil in Japan
Packing
- 45 - Recopilación y Análisis de Estudios Tecnológicos de Maderas Peruanas
Light Packing
- 46 - ECUADOR, Inventario y Aprovechamiento de los Bosques del Sur Ecuatoriano
Pallets
- 48 - The strength properties of timbers
Pencils
- 67 - Maderas latinoamericanas. VIII, Calophyllum brasilense, Couratari panamensis, Dendropanax arboreum y Bombacopsis sessilis
Matches
- 71 - Proprietes physiques et mecaniques des bois tropicaux, premier supplement
Door Cores
- 76 - Descripción General y Anatómica de 105 Maderas del Grupo Andino.
Coffin
- 78 - Amazonian Timbers for the International Market
Molding
- 79 - Padronização da Nomenclatura Comercial Brasileira das Madeiras Tropicais Amazônicas, Sugestão
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