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Blunting Effect Boring 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 Nailing Natural Durability Natural Growth Defects Numerical Data Odor Planing Polishing Product Sources References Regions of Distribution Resistance to Impregnation Response to Hand Tools Routing & Recessing Sanding Sapwood Color Scientific Name Screwing Staining Steam Bending Strength Properties Substitutes Synonyms Texture Toxicity Trade Name Tree Identification Tree Size Turning		Scientific Name Cylicodiscus gabunensis Trade Name Okan Family Name Leguminosae Synonyms Cyrtoxiphus staudtii, Erythrophleum gabunense, Erythrophleum l Common Names Adada, Adadua, Adoum, Adum, African greenheart, Aja-igi, Anyan, Bokoka, Boueman, Bouemon, Denya, Djom, Doum, Edoum, Edum, Ekam, Emang, Eyee, Imbeli-deli, Inbeli-deli, Kendum, Lisan, Mbeli-deli, Mobonran, Muduma, Nkassa, Ode owese, Odekowese, Odenya, Okain, Okan, Olisan, Olosan, Osung, Owese, Usi, Uzhi Regions of Distribution Africa Countries of Distribution  [VIEW MAP] Benin, Cameroon, Gabon, Ghana, Ivory Coast, Liberia, Nigeria, Sierra Leone, Togo Common Uses Agricultural implements, Boat building (general), Boat building: decking, Boat building: framing, Bridge construction, Carvings, Charcoal, Crossties, Decks, Dockwork, Factory flooring, Flooring, Flooring: commercial heavy traffic, Flooring: industrial heavy traffic, Fuelwood, Furniture, Heavy construction, Joinery, Ladders, Light construction, Marine construction, Millwork, Mine timbers, Piling, Poles, Posts, Railroad ties, Sporting Goods, Turnery, Vehicle parts, Veneer, Wharf construction Environmental Profile Secure within its range Data source is World Conservation Monitoring Center Distribution Overview Common in the rain forests of Sierra Leone to the Cameroons and Gabon. Heartwood Color Red Yellow Brown Green/grey Pink Orange Yellow to golden-yellow to orange Greenish to greyish Brown Reddish brown Pale brown Dark brown Dark brown Sapwood Color Pink/Red Clearly differentiated from the heartwood White to yellow Is 2 to 3 inches (5 to 7.5 cm) wide. Grain Interlocked Figure Closed Stripe (figure) Distinct (figure) Wavy Irregular Interlocked Striped figure Distinct figure Wavy Moderately to severely interlocked Irregular Grain is very irregular and closely interlocked, producing an attractive stripe or roey figure on quartered surfaces. Texture Medium Fine Coarse Coarse Medium to coarse Medium Has a waxy appearance and feel Luster Lustrous Pronounced Natural Growth Defects Yellowish deposits in vessels Natural Durability Susceptible to insect attack Durable Perishable Non-resistant to powder post beetles Resistant to termites Non-durable Non-resistant to termites Non-resistant to marine borers Resistant to powder post beetles Very durable Resistant to attack from termites (Isoptera) Susceptible to attack from powder post (Lyctid & Bostrychid) beetles Resistant to attack from marine borers Resistant to attack from powder post (Lyctid & Bostrychid) beetles Pinworms (ambrosia beetles) are commonly present Felled logs are not resistant to attack by Pinworm (ambrosia beetle) Durable The heartwood has high natural resistance to attack by decay fungi and termites. Sapwood is not durable and is readily attacked by powder-post beetle. The wood is reported to resist attack by marine-borers. The timber has excellent weathering qualities, and has high resistance to wear. Although the wood is considered to be highly suitable for flooring, it is very difficult to machine Odor May have a slightly disagreeable smell when green Seasoned wood has no discernible odor or taste Light-Induced Color Change Darker Toxicity Unspecified toxicity Respiratory effects Kiln Schedules Dry at a slow speed UK=B US=T2C2/T2C1 Fr=2 Kiln Drying Rate (in days) is rather slow T3-C2 (4/4); T2-C1 (8/4) US Schedule B (4/4) United Kingdom Drying (speed) is fast Dry at a moderate speed Drying Defects Moderate surface checking Moderate end spitting Slight surface checking Severe surface checking Severe end splitting No end splitting Moderate twist/warp End splitting Defects in the form of surface warping is slight Ease of Drying Moderately Difficult to Difficult Slowly Dries slowly Difficult Kiln Drying Rate Naturally dries slowly Very slow (>28 days for boards < 32 mm, to >84 days for boards >= 63 mm) Tree Identification Bole/stem form is buttressed Bole/stem form is straight Bole/stem form is cylindrical Bole/stem form is not buttressed Tree Size Trunk diameter is 150-200 cm Tree height is 20-30 m Bole length is 30-40 m Bole length is 20-30 m Sapwood width is 0-5 cm Sapwood width is 10-15 cm Tree height is 10-20 m Bole length is 10-20 m Tree height is 30-40 m Trunk diameter is 100-150 cm Bole length is 0-10 m Product Sources Exporting countries are reported to include Sierra Leone, Liberia, Ivory Coast, Ghana, Nigeria, and the Cameroons. Substitutes Timber hard and heavy Lignum-Vitae substitute Comments General finishing qualities are rated as good Strength properties are mid-way between those of European beech (Fagus ) and Greenheart (Ocotea ) Blunting Effect High to severe Blunting effect on machining is fairly severe Blunting effect on machining is moderate Boring Easy Fair results Cutting Resistance Fairly Difficult to Very Difficult to saw Cutting Resistance with dry wood is difficult Cutting Resistance with dry wood is easy Difficult to saw Responds satisfactorily to narrow bandsawing Gluing Fairly Easy to Very Easy Difficult to glue Easy to glue Very good properties Mortising Fairly Easy to Very Easy Difficult to mortise Moulding Fairly Easy to Very Easy Difficult to mould Interlocked grain produces distinct ribbon figure Nailing Fairly Easy to Very Easy Difficult to nail Pre-boring recommended Planing Fairly Easy to Very Easy Difficult to plane Planes well, to a good finish Interlocked grain produces distinct ribbon figure Interlocked grain tends to tear in planing and the wood works with difficulty. A reduced cutting angle of 10 degrees is suggested for planing quarter-sawn material. Resistance to Impregnation Resistant heartwood Resistant sapwood Heartwood is very resistant Sapwood is resistant Sapwood is moderately resistant Heartwood is resistant Response to Hand Tools Fairly Difficult to Difficult to Work Easy to Work Difficult to machine Easy to machine Routing & Recessing Routing yields good results Sanding Very Good to Excellent Results Fair to Good Results Good sanding finish Screwing Possible if prebored Difficult to screw Turning Easy to turn Good results Steam Bending Poor Buckling and fiber rupturing are very common Polishing Fair to Good Results Satisfactory results Grain filling required for satisfactory results Staining Finish is generally satisfactory Poor results Strength Properties Modulus of Elasticity (stiffness) = high Bending strength (MOR) = high Hardness (side grain) = very hard Shearing strength (parallel to grain) = high Max. crushing strength = high Density (dry weight) = 61-67 lbs/cu. ft Max. crushing strength = very high Shearing strength (paralell to grain) = very high Shrinkage, Tangential = fairly large Density (dry weight) = 53-60 lbs/cu.ft. Shrinkage, Radial = moderate Shrinkage, Volumetric = fairly large Shrinkage, Tangential = large Shrinkage, Radial = large Shrinkage, Radial = fairly large Bending strength (MOR) = very high Shrinkage, Volumetric = moderate Shrinkage, Tangential = small Shrinkage, Tangential = moderate Shrinkage, Volumetric = large Shrinkage, Radial = small Shearing strength (parallel to grain) = low Density (dry weight) = 67-75 lbs/cu. ft. Work to Maximum Load = low Shrinkage, Tangential = very small Shrinkage, Radial = very small Shearing strength (parallel to grain) = very low Shearing strength (parallel to grain) = medium Modulus of Elasticity (stiffness) = very high Modulus of Elasticity (stiffness) = medium Hardness (side grain) = medium Hardness (side grain) = hard Density (dry weight) = 75+ lbs/cu. ft. Density (dry weight) = 46-52 lbs/cu. ft. Bending strength (MOR) = medium Numerical Data Item Green Dry English Bending Strength 14400 20861 psi Density 59 lbs/ft3 Hardness 2843 lbs Maximum Crushing Strength 8203 11868 psi Shearing Strength 2798 psi Stiffness 2093 2518 1000 psi Work to Maximum Load 9 12 inch-lbs/in3 Specific Gravity 0.72 Weight 60 57 lbs/ft3 Radial Shrinkage 5 % Tangential Shrinkage 8 % Volumetric Shrinkage 12 % Item Green Dry Metric Bending Strength 1012 1466 kg/cm2 Density 945 kg/m3 Hardness 1289 kg Maximum Crushing Strength 576 834 kg/cm2 Shearing Strength 196 kg/cm2 Stiffness 147 177 1000 kg/cm2 Work to Maximum Load 0.63 0.84 cm-kg/cm3 Specific Gravity 0.72 Weight 961 913 kg/m3 Radial Shrinkage 5 % Tangential Shrinkage 8 % References Armstrong, F.H.,1960,The Strength Properties of Timber,Forest Products Research Laboratory, London Bulletin,No.45 Banks, C.H. and J.P. Schoeman. 1963. Railway Sleeper and Crossing Timbers. Bulletin No. 41, Republic of South Africa. The Government Printer, Pretoria, South Africa. 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] Bentum, A.L.K.,1970,Properties of Ghanaian Timbers - Denya (Okan,F.P.R.I. Ghana Technical Newsletter, 4(4,pp21-2 Bois et Forets des Tropiques,1955,Okan (Adoum) - Cylicodiscus gabonensis,Bois et Forets des Tropiques,No.43,pp11-14 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 Bolza, E.,1976,Timber and Health,Div. Building Res. C.S.I.R.O. Australia Bond, C.W.,1950,Colonial Timbers,Sir Issac Pitman & Sons Ltd. London Boone, R.S., C.J. Kozlik, P.J. Bois and E.M. Wengert. 1988. Dry Kiln Schedules for Commercial Woods: Temperate and Tropical. United States Department of Agriculture, Forest Service, General Technical Report FPL-GTR-57, Forest Products Laboratory, Madison, Wisconsin. Chudnoff, M.,1984,Tropical Timbers of the World,U.S.A. Department of Agriculture, Forest Service, Forest Products,Laboratory, Madison. Dalziel, J.M.,1937,The Useful Plants of West Tropical Africa,Crown Agents for the Colonies Erfurth, T., Rusche, H.,1976,The Marketing of Tropical Wood A. Wood Species from African Moist Forests,F.A.O. Forestry Department Farmer, R.H.,1972,Handbook of Hardwoods,HMSO Forests Products Research Laboratory, U.K.,1956,A Handbook of Hardwoods,Forest Products Research Laboratory, Princes Risborough, Department of,Science and Industrial Research, Building Research Establishment Fortin, Y., Poliquin, J.,1976,Natural Durability and Preservation of 100 Tropical African Woods,International Development Research Centre, Canada Ghana - Timber Marketing Board,1969,Ghana Hardwoods,Timber Marketing Board Hedin, L.,1930,Etude sur la Foret et les Bois du Cameroun,Haut-Commissaire de la Cameroun 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. Howard, A.L.,1948,A Manual of Timbers of the World.,Macmillan & Co. Ltd. London 3rd ed. Hughes, J.F.,1971,The Principal Timber Trees of Cameroon,Unpublished data Irvine, F.R.,1961,Woody Plants of Ghana,O.U.P. London Jay, B.A.,1968,Timbers of West Africa,TRADA, Red Booklet Series 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 Kennedy, J.D.,1936,Forest Flora of Southern Nigeria,Government Printer Lagos Kinloch, D., Miller, W.A.,1949,Gold Coast Timbers,Govt. Printer Gold Coast Kloot, N.H., Bolza, E.,1961,Properties of Timbers Imported into Australia,C.S.I.R.O. Forest Products Division Technological Paper,No.12 Kribbs, D.A. 1959. Commercial Foreign Woods on the American Market. Buckhout Lab., Dept. of Botany, The Pennsylvania State University, University Park, Pennsylvania. Kribs, D.A.,1950,Commercial and Foreign Woods on the American Market (a manual to their,structure, identification, uses and distribution,U.S.A. Penn. State College, Tropical Woods Laboratory Kryn, J.M., Forbes, E.W.,1959,The Woods of Liberia,U.S.A. Department of Agriculture,Forest Products Laboratory, Madison,,Report No. 2159 Lavers, G.M. 1967. The Strength Properties of Timbers. Forest Products Research Bulletin, No. 50 (Spersedes Bulletin No. 45). Ministry of Technology, Her Majesty's Stationery Office, London. Lavers, G.M.,1983,The Strength Properties of Timber (3rd ed. revised Moore G.L.,Forest Products Research Laboratory, Princes Risborough, Building Research,Establishment Report (formerly Bulletin No.50) Nairn, P.M., Editor. 1936. Wood Specimens - 100 Reproductions in Color - A Series of Selected Timbers Reproduced in Natural Color with Introduction and Annotations by H.A. Cox. The Nema Press, Proprietors of Wood, London. Organisation for European Economic Co-operation,1951,African Tropical Timber (Nomenclature, Description,OEEC Rendle, B.J.,1969,World Timbers (3 Vols.,Ernest Benn Ltd. London Sallenave, P.,1955,Proprietes Phyiques et Mecaniques des Bois Tropicaux de l'Union Francaise,C.T.F.T Sallenave, P.,1971,Proprietes Physiques et Mecaniques des Bois Tropicaux (Deuxieme,Supplement,C.T.F.T. Spalt, H.A., Stern, W.L.,1956,Survey of Africa Woods 2,Tropical Woods 16(106) pp65-97 Spalt, H.A., Stern, W.L.,1956,Survey of African woods 1,Tropical Woods,115(105,pp 13-38 Taylor, C.J.,1960,Synecology and Silviculture in Ghana,University College of Ghana Thomas Nelson and Sons Timber Development Association Ltd.,1955,World Timbers (3 Vols.,Timber Development Association Ltd. Timber Development Association,1948,Some New Timbers and Their Uses No. 34,Timber Development Association Limited, London [TRADA] U.A.C.O. Timber Review,1971,Some Straight forward information about a very strong and very durable,wood,U.A.C.O. Timber Review,20,pp12-3 Unwin, A.H.,1920,West African Forests and Forestry,T. Fisher Unwin Ltd. London