Search for

Clicking any heading in the main data area (at right) will scroll the page back to this top position. Use the following links to jump to the associated section in the main data. Blunting Effect Boring Carving Common Names Common Uses Countries of Distribution Cutting Resistance Distribution Overview Drying Defects Ease of Drying Environmental Profile Family Name Grain Heartwood Color Luster Mortising Moulding Movement in Service Nailing Natural Durability Numerical Data Odor Planing Polishing References Regions of Distribution Resistance to Impregnation Resistance to Splitting Response to Hand Tools Routing & Recessing Sanding Sapwood Color Scientific Name Strength Properties Texture Trade Name Tree Identification Tree Size Turning Scientific Name Tetrapleura tetraptera Trade Name Akpa Family Name Leguminosae Common Names Akpa, Akposso, Angular pod, Apapa, Aprekese, Aridan, Arido, Bubao, Budjo, Buleu, Ebuk, Edeminang, Esem, Ighimiakia, Ighirehimi, Igmikkia, Ikhememi, Ikoho, Imiminje, Ka-loma, Ka-segbel, Kokondu, Kokundui, Kyeke, Ossgosha, Prekese Regions of Distribution Africa Countries of Distribution  [VIEW MAP] Cameroon, Congo, Ivory Coast, Liberia, Senegal, Sudan, Uganda Common Uses Agricultural implements, Barge fenders, Bedroom suites, Boat building (general), Building materials, Cabinetmaking, Chairs, Chests, Clogs, Concealed parts (Furniture), Core Stock, Desks, Dining-room furniture, Docks, Dockwork, Domestic flooring, Dowell pins, Dowells, Drawer sides, Excelsior, Fine furniture, Floor lamps, Flooring, Furniture , Furniture components, Furniture squares or stock, Harbor work, Hatracks, Heavy construction, Interior construction, Interior trim, Joinery, Kitchen cabinets, Light construction, Living-room suites, Marine construction, Medicinal use, Millwork, Moldings, Naval architecture, Office furniture, Plywood, Posts, Shipbuilding, Turnery, Wheelwright work, Windows Environmental Profile Status has not been officially assessed Distribution Overview The genus Tetrapleura consists of two species which occur in tropical Africa. T. tetraptera is widely distributed in tropical Africa, and is often found in secondary deciduous forests. Heartwood Color White Brown Reddish brown Pale red to pink Light red Darkens after prolonged exposure Sapwood Color White White to yellow Well defined Paler than heartwood Grey Clearly differentiated from the heartwood Grain Straight Even Interlocked Straight Interlocked Texture Medium Coarse Fine Medium coarse to coarse Luster High Natural Durability Perishable Non-resistant to pinhole borers Non-resistant to termites Susceptible to insect attack Durable Moderately durable Susceptible to attack from powder post (Lyctid & Bostrychid) beetles Non durable Moderately resistant to termite (Isoptera) attack Moderately resistant to attack by termites Odor No specific smell or taste Drying Defects May collapse and distort Ease of Drying Reconditioning Treatement Fairly difficult to dry Kiln-Drying should be preceded by air-seasoning to minimize degrade Tree Identification Bole/stem form is buttressed Tree Size It is often unbuttressed, but may occasionally develop small, sharp buttresses. Blunting Effect Moderate Boring Fairly easy to very easy Fair to good results Responds well to machine tools to produce clean bored surfaces Carving Fair to Good Results Fairly Easy to Very Easy Good results Cutting Resistance Easy to saw Saws fairly well Cutting Resistance with green wood is easy Cutting Resistance with dry wood is easy The timber saws fairly well but material with irregular grain may produce woolly surfaces Mortising Fairly Easy to Very Easy Easy to mortise Mortised surfaces are generally clean Moulding Fair to Good Results Fairly Easy to Very Easy Moulded surfaces tend to be clean Good moulding properties Movement in Service Stable when seasoned Holds shape well after manufacture Nailing Easy to nail Planing Fair to Good Results Fairly Easy to Very Easy Responds well to ordinary machine tools in all operations Resistance to Impregnation Permeable sapwood Resistant heartwood Resistant sapwood Sapwood is moderately resistant Heartwood is resistant Resistance to Splitting Poor Response to Hand Tools Responds Readily Easy to Work Easy to machine Responds well to ordinary hand tools in most operations Routing & Recessing Fairly Easy to Very Easy Fair to Good Results Good routing qualities Sanding Fair to Good Results Yields relatively smooth surfaces Good sanding properties Turning Fair to Good Results Fairly Easy to Very Easy Yields fairly smooth surfaces The timber responds readily to machine tools to yield fairly smooth surfaces in turning operations Polishing Satisfactory results Strength Properties Max. crushing strength = medium Bending strength (MOR) = medium Shrinkage, Radial = small Density (dry weight) = 38-45 lbs/cu. ft. Density (dry weight) = 31-37 lbs/cu. ft. Shrinkage, Tangential = small Shrinkage, Tangential = moderate Shrinkage, Tangential = fairly large Shrinkage, Radial = moderate Hardness (side grain) = soft Bending strength (MOR) = high Density and most strength properties of the wood are reported to vary considerably. Fruits and seeds from the tree are reported to contain tannin which are used for flavoring and also for medicinal purposes. Numerical Data Item Green Dry English Bending Strength 9794 15046 psi Density 36 lbs/ft3 Hardness 995 lbs Maximum Crushing Strength 4248 7139 psi Shearing Strength 1862 psi Stiffness 1519 1764 1000 psi Weight 35 28 lbs/ft3 Radial Shrinkage 3 % Tangential Shrinkage 7 % Item Green Dry Metric Bending Strength 688 1057 kg/cm2 Density 576 kg/m3 Hardness 451 kg Maximum Crushing Strength 298 501 kg/cm2 Shearing Strength 130 kg/cm2 Stiffness 106 124 1000 kg/cm2 Weight 560 448 kg/m3 Radial Shrinkage 3 % References Bolza, E., Keating, W.G.,1972,African Timbers - the Properties, Uses and Characteristics of 700 Species,C.S.I.R.O. Div. of Building Research Eggeling, W.J.,1940,Indigenous Trees of Uganda,Govt. Printer Entebbe Uganda Irvine, F.R.,1961,Woody Plants of Ghana,O.U.P. London Keay, R.W.J. 1989. Trees of Nigeria. Revised Version of Nigerian Trees. Clarendon Press, Oxford. Keay, R.W.J.,1964,Nigerian Trees Vol.2,Nigeria Federal Department of Forest Research, Ibadan Kryn, J.M., Forbes, E.W.,1959,The Woods of Liberia,U.S.A. Department of Agriculture,Forest Products Laboratory, Madison,,Report No. 2159 Lebacq, L., Dechamps, R.,1967,Contribution a un Inventaire de Forets du Nord-kasai,Musee Royal de L'Afrique Centrale Belgium Annals Series 8 No.5 Sallenave, P.,1955,Proprietes Phyiques et Mecaniques des Bois Tropicaux de l'Union Francaise,C.T.F.T Savill, P.S., Fox, J.E.D.,1967,Trees of Sierra Leone Takahashi, A.,1978,Compilation of Data on the Mechanical Properties of Foreign Woods (Part,III) Africa,Shimane University, Japan, Research Report on Foreign Wood No. 7 Unwin, A.H.,1920,West African Forests and Forestry,T. Fisher Unwin Ltd. London