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Blunting Effect Boring Carving Comments Common Names Common Uses Countries of Distribution Cutting Resistance Distribution Overview Drying Defects Ease of Drying Environmental Profile Family Name Gluing Grain Heartwood Color Kiln Drying Rate Kiln Schedules Light-Induced Color Change Luster Mortising Moulding Movement in Service Nailing Natural Durability Natural Growth Defects Numerical Data Odor Planing Polishing Product Sources References Regions of Distribution Resistance to Impregnation Resistance to Splitting Response to Hand Tools Routing & Recessing Sanding Sapwood Color Scientific Name Screwing Strength Properties Texture Trade Name Tree Identification Tree Size Turning Veneering Qualities		Scientific Name Khaya nyassica Trade Name African mahogany Family Name Meliaceae Common Names Acajou umbaua, African mahogany, Banket mahogany, East African mahogany, Iluli, Kaonde, M'bane, Mahogany, Mbamba, Mbaua, Mbawa, Mkangazi, Mozambique mahogany, Mtondoo, Mtondoro, Mubaba, Mubawa, Mululu, Mururu, Muvava, Muwawa, Myofu, Nyasaland mahogany, Red mahogany, Umbaba, Umbaua Regions of Distribution Africa Countries of Distribution  [VIEW MAP] Malawi, Mozambique, South Africa, Tanzania, Zaire, Zambia, Zimbabwe Common Uses Agricultural implements, Bedroom suites, Boat building (general), Boat building, Boat building: planking, Building materials, Cabinetmaking, Canoes, Carvings, Chairs, Chests, Clogs, Desks, Dining-room furniture, Drawer sides, Exterior trim & siding, Exterior uses, Fine furniture, Flooring, Furniture , Furniture, Interior construction, Interior trim, Joinery, Kitchen cabinets, Lifeboats, Light construction, Living-room suites, Mathematical instruments, Medicinal use, Moldings, Office furniture, Paneling, Particleboard, Pencil, Plywood corestock, Plywood, Pulp/Paper products, Radio - stereo - TV cabinets, Shakes, Sheathing, Shingles, Shipbuilding, Siding, Sporting Goods, Tables, Toys, Turnery, Veneer, Wardrobes, Windows Environmental Profile Status has not been officially assessed Distribution Overview East and Central Africa Heartwood Color Brown Red Purple Black Pink Pale red to pink Reddish brown Red Dark brown Bright red or pink when first cut, fading to an even, light pink-brown when dry. It eventually matures into a lustrous golden brown color Sapwood Color White Yellow Pink Paler than heartwood Well defined White to yellow Freshly-Cut sapwood is lighter in color than the heartwood, but it darkens to a similar color. Grain Figure Straight Interlocked Wavy Stripe (figure) Other (figure) Closed Even Irregular Rippled (figure) Fiddleback (figure) Straight Interlocked Wavy Striped figure Other figure Rippled figure May be wavy or curly Irregular Fiddleback figure Texture Coarse Medium Medium Fine to medium Uniform Luster Medium Low Lustrous Slightly lustrous Natural Growth Defects Whitish deposits in vessels Natural Durability Durable Resistant to termites Moderately durable Durable Susceptible to attack from powder post (Lyctid & Bostrychid) beetles Resistant to attack from termites (Isoptera) Non durable Resistant to attack from powder post (Lyctid & Bostrychid) beetles Heartwood moderately resistant to decay Weathers extremely well Odor No specific smell or taste Light-Induced Color Change Darker Kiln Schedules Drying (speed) is fast Kiln Drying Rate (in days) is rapid Drying Defects Splitting Slight twist/warp Slight end splitting Wild grain or tension wood may cause distortion because of excessive and uneven shrinkage. Ease of Drying Fairly Easy Easy The timber dries rapidly with little degrade, except in boards with wild grain or tension wood. Kiln Drying Rate Rapid (<10 days for boards < 32 mm, to <30 days for boards >= 63 mm) Tree Identification Bole/stem form is straight Bole/stem form is buttressed Bole/stem form is cylindrical Tree Size Bole length is 0-10 m Bole length is 10-20 m Tree height is 10-20 m Tree height is 20-30 m Trunk diameter is 100-150 cm Trunk diameter is 150-200 cm Trunk diameter is 200-250 cm Trunk diameter is 250-300 cm Develops boles that are usually straight, cylindrical and free of branches for 50 to 60 feet (15 to 18 m). Product Sources The timber is often marketed together with those of other Khaya species as African mahogany. Supplies in the lumber form are plentiful in a wide variety of sizes. The wood is also available in plywood form from many suppliers at a moderate price Comments Abnormal Wood Tissue Abnormal wood tissue in the form of tension wood may be present. General finishing qualities are rated as good The timber is generally similar in strength and other properties and is used for the same purposes as other African mahoganies, K. ivorensis and K. anthotheca . Blunting Effect Medium effect Boring Responds readily to boring operations Easy Carving Good carving properties Cutting Resistance Easy to saw Cutting Resistance with green wood is easy Cutting Resistance with dry wood is easy No difficulty has been encountered sawing smaller logs. However, some logs are so large that there is a problem with machinery breaking down. Saws may bind during rip-sawing, and may burn during cross-cutting. Correct saw maintenance techniques are necessary to prevent a woolly finish. Gluing Easy to glue Glues well Mortising Moderately easy to mortise Finishes satisfactorily Easy to mortise Material containing wild grain and tension wood may be difficult to mortise. Moulding Moulding ease is moderate Good moulding properties Easy to mould Movement in Service Medium The timber is dimensionally stable after seasoning to the appropriate moisture content. Nailing Nails hold poorly The nailing properties of this timber are variable, and are believed to be generally poor. Pre-boring is advised, especially when nailing areas close to the edge of backsawn boards. Planing Ease of planing is moderate Planes well, to a good finish Reduced cutting angles are recommended in planing quartersawn material, or pieces with interlocked grain. Resistance to Impregnation Heartwood is highly resistant Sapwood is moderately resistant Resistance to Splitting Poor Response to Hand Tools Easy to Work Easy to machine The wood responds well to hand tools Routing & Recessing Routing is easy Routing and recessing qualities are rated as good in straight grain material Sanding Good sanding qualities Screwing Pre-Boring suggested before screwing Turning Fairly Easy to Very Easy Finish is generally satisfactory Turns fairly well Good results Veneering Qualities Easy to cut There is slight to moderate drying degrade and the potential for buckles and splits Suitable for slicing Suitable for peeling No drying degrade. Dries flat without splitting Bolt preparation requires steaming Polishing Good results High polish Strength Properties Density (dry weight) = 38-45 lbs/cu. ft. Density (dry weight) = 31-37 lbs/cu. ft. Max. crushing strength = medium Bending strength (MOR) = low Shearing strength (parallel to grain) = very low Shrinkage, Radial = very small Modulus of Elasticity (stiffness) = low Hardness (side grain) = soft Shrinkage, Tangential = small Modulus of Elasticity (stiffness) = very low Density (dry weight) = 46-52 lbs/cu. ft. Shearing strength (parallel to grain) = medium Bending strength (MOR) = medium Shrinkage, Tangential = very small Density (dry weight) = 23-30 lbs/cu. ft. Shrinkage, Radial = small Shearing strength (parallel to grain) = low Max. crushing strength = low Bending strength (MOR) = very high Bending strength (MOR) = high Numerical Data Item Green Dry English Bending Strength 7429 11443 psi Density 39 lbs/ft3 Hardness 1075 lbs Maximum Crushing Strength 3482 6037 psi Shearing Strength 1437 psi Static Bending 7134 psi Stiffness 1190 1376 1000 psi Specific Gravity 0.52 Weight 36 29 lbs/ft3 Radial Shrinkage 2 % Tangential Shrinkage 5 % Item Green Dry Metric Bending Strength 522 804 kg/cm2 Density 624 kg/m3 Hardness 487 kg Maximum Crushing Strength 244 424 kg/cm2 Shearing Strength 101 kg/cm2 Static Bending 501 kg/cm2 Stiffness 83 96 1000 kg/cm2 Specific Gravity 0.52 Weight 576 464 kg/m3 Radial Shrinkage 2 % References Alan Schwartz. Rio Rivuma, Boston, MA. Personal Communication, 1993. Audas, J.W.,Native Trees of Australia,Whitcombe & Tombs PTY. Ltd Banks, C.H., Schoeman, J.P., Otto, K.P.,1977,The Mechanical Properties of Timbers with particular reference to South,Africa,South African Forestry Research Institute Bulletin,(Ed.,Schoeman, J.P. 1973 & Otto K.P. 1976,No.48 Banks, C.H.,1954,The Mechanical Properties of Timbers with Particular Reference to those,grown in the Union of South Africa,Journal of the South African Forestry Association,No. 24 pp.44-65,[South,African Forestry Journal] Bois, P.J.,1966,The Strength Properties of Tanzania Timbers,Tanzania Forest Div. Util. Sec. Moshi Tech. Note, No.35 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 Bryce, J.M., Norcross, H.,1961,The Resistance of Tanganyika Timbers to Impregnation,Tanzania Forest Dept. Util. Sec .Tech. Note,No.28 Erfurth, T., Rusche, H.,1976,The Marketing of Tropical Wood A. Wood Species from African Moist Forests,F.A.O. Forestry Department Fortin, Y., Poliquin, J.,1976,Natural Durability and Preservation of 100 Tropical African Woods,International Development Research Centre, Canada France - C.T.F.T./C.T.B.,1982,Guide pour le Choix des Essences Deroulables-pour la fabrication du,contreplaque,C.T.F.T./C.T.B. France Greenway, P.J.,1947,Mahogany in East Africa 1 The Khayas,East African Agricultural Journal,13,pp8-14,[East African Agricultural,and Forestry Journal] HMSO, 1981. Handbook of Hardwoods, 2nd Edition. Revised by R.H. Farmer. Department of the Environment, Building Research Establishment, Princes Risborough Laboratory, Princes Risborough, Aylesbury, Buckinghamshire. I.U.F.R.O.,1973,Veneer Species of the World,Assembled at F.P.L. Madison on behalf of I.U.F.R.O. Working Party on,Slicing and Veneer Cutting Kline, M. 1981. Khaya spp. - African mahogany. In A Guide to Useful Woods of the World. Flynn Jr., J.H., Editor. King Philip Publishing Co., Portland, Maine. Page 201-202. Lincoln, W.A. 1986. World Woods in Color. Linden Publishing Co. Inc., Fresno, California. McCoy-Hill, M.,1955,Timbers of Tanganyika - Afrormosia and East African Mahogany,Timber Technology,63(2196, pp538-9 Murira, K.,1984,Natural Durability Tests of Tanzanian Timbers 1955 - 1982,Tanzania Forestry Research Institute, Timber Utilisation Research Centre,,Moshi. Palgrave, K.C.,1977,Trees of Southern Africa,Cape Town South Africa Pardy, A.A.,1953,Notes on Indigenous Trees and Shrubs of S.Rhodesia - Khaya nyasica Stapf,ex Baker f.,Ministry of Agriculture and Lands S.Rhodesia Bulletin No.1712 Scott, M.H.,1950,Notes on the more Important African Timbers Imported into the Union with,Special Ref. to Port. E.A. Species,Journal of the South African Forestry Association,No.19,pp18-62,[South,African Forestry Journal] 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 Tanzania - Timber Marketing Co. Ltd.,1978,Timber from Tanzania Tanzania Forest Department,1961,The Movement of Timbers Technical Note No.29,Tanzania Forest Department, Utilisation Division Technical Note Tanzania Forest Division,1966,Kiln Drying Schedules for Tanzania Timbers Technical Note no.38,Tanzania Forest Div. Util. Sec. Moshi Tanzania Forestry Department,1961,Timbers of Tanganyika - Khaya nyasica,Tanzania Forestry Department, Utilisation Section, Moshi - Timbers of,Tanganyika Tanzania Forestry Department,1963,Timbers of Tanganyika - Syzygium guineense,Tanzania Forestry Department, Utilisation Section, Moshi - Timbers of,Tanganyika Timber Development Association,1948,Some New Timbers and Their Uses No. 34,Timber Development Association Limited, London [TRADA] Zambia Forest Department,1979,Timbers of Zambia Khaya nyasica and Kirkia acuminata,Zambia Forest Department, Division of Forest Products Research Technical,Note