ESSOMBO (Rauvolfia caffra)
Trade Name
Essombo
Scientific Name
Rauvolfia caffra Sord.
Family
APOCYNACEAE
Common Names
Esoma (Gabon); Sab (Congo); Ontsousouele (Congo); Essombo (Cameroon); Essomba (Cameroon); Essombo
Scientific Name Synonyms
Rauvolfia welwitschii Stapf; Rauvolfia natalensis Sond.; Rauvolfia macrophylla Stapf
Description Of The Tree
Botanical Description
The tree reaches a height of 32 m. The bole is cylindrical, usually straight and may be up to 20 m in length. The trunk diameter attains 70 to 100 cm.
Natural Habitat
Rauvolfia caffra is common along streams and in secondary formations.
Wood Identification
Anatomic Description Of Wood
Wood diffuse porous. Vessels exclusively solitary (over 90%). Tangential diameter of vessel lumina 100 to 150 micras (small). Vestured pits. Vessels per mm2 more than 20 (very abundant). Simple perforation plates. Vessel-ray pits similar to intervessel pits in Apotracheal axial parenchyma diffuse and/or diffuse in aggregates. Prismatic crystals in chambered axial parenchyma cells and/or in fibers. Prismatic crystals in short chains in chambered axial parenchyma cells. 5 to 8 cells per parenchyma strand. 4 to 10 rays per mm (medium). Rays non-storied. Rays 1 to 4 seriate. Prismatic crystals in radial alignment in procumbent ray cells (chambered cells). Oil and/or mucilage cells associated with the axial and/or ray parenchyma (idioblasts). Body ray cells procum Non-septate fibers. Fibers with distinctly bordered pits.
Availability
Cites Status
Unrestricted
General Wood Description
Color
The sapwood is pale yellow. The heartwood is beige to pale brown , it is not clearly demarcated.
Grain
Straight; grain has no particular influence on drying, machining and finishing qualities.
Texture
This species is usually reported to have a fine texture.
Natural Durability
Slightly durable to decay. This species needs preservative treatment for uses with risks of occasional re-humidification. It is not suited for uses with risks of permanent or long-lasting humidification. The heartwood is sensible to termites and Lyctus at
Natural durability index (1= Very high durability, 7=Vey low durability)
6
Resistance To Impregnation
Difficult to treat with only a low penetration of the preservative products.
Wood Physical Properties
Basic Density or Specific Gravity (O.D. weight/vol. green) (g/cm³)
0.49
Air-dry Density (Weight and volume at 12%MC) (g/cm³)
0.53
Total shrinkage Tangential (Saturated to 0%MC) (%)
8.2
Total shrinkage Radial (Saturated to 0%MC) (%)
4.2
Drying Defects
Ease of Drying: Drying is rather slow and sometimes difficult to perform. Drying Defects: Risks of distortions.
Dimensional stability ratio (Total Tangential Shrinkage %/Total Radial Shrinkage %)
2.0
Wood Chemical Properties
Wood Mechanical Properties
Bending Strength (MOR),12%MC (kgf/cm²)
706
Stiffness (MOE) 12%MC (kgf/cm²)
93006
Compression parallel to fiber 12%MC (kgf/cm²)
448
Compression perpendicular to fiber 12%MC (kgf/cm²)
53
Shear strength radial 12%MC (kgf/cm²)
78
Janka hardness (side) 12%MC (kgf)
344
Janka hardness (end grain) 12%MC (kgf)
448
Workability
Sawing
It is easy to saw.
Rotary Veneer Cutting
Not suitable for veneering.
Sliced Veneer
Not suitable for veneering.
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
Easy; no particular problems.
Boring
Easy; no particular problems.
Mortising
Easy; no particular problems.
Nailing
No particular problem.
Gluing
Glues well if basic gluing technical rules are followed.
Sanding
Easy to perform; it gives good results.
Polishing
Can be polished without surface preparation.
Response To Hand Tools
No particular problems.
REFERENCED USES
End Uses Summary
HOUSING GENERAL, boards, frames, FURNITURE AND CABINETS, common furniture, PACKING, light packing, OTHER AND MUSICAL INSTRUMENTS, 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
Furniture Cabinets
- 21 - Tropical timbers of the world. Part III-Southeast Asian and Oceanian Species.
Furniture, Common
- 23 - Handbook of Hardwoods
Packing
- 45 - Recopilación y Análisis de Estudios Tecnológicos de Maderas Peruanas
Light Packing
- 46 - ECUADOR, Inventario y Aprovechamiento de los Bosques del Sur Ecuatoriano
Molding
- 79 - Padronização da Nomenclatura Comercial Brasileira das Madeiras Tropicais Amazônicas, Sugestão
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