Common Name: Tatabu
Scientific Name: Diplotropis purpurea
Wood Appearance: Tatabu is a heartwood that is typically chocolate brown when freshly cut, transitioning to a lighter brown upon drying. It may occasionally exhibit a grayish-brown hue, often with distinctive dark gold-colored stripes or narrower stripes of a lighter brown. The heartwood is clearly demarcated from the narrow sapwood, which is grayish or pinkish gray. The wood’s texture is coarse to very coarse, with a grain that is usually straight to slightly interlocked or sometimes slightly wavy. Tatabu possesses a high and golden luster in proper light, often presenting a waxy appearance. It is without a distinctive odor or taste.
Physical Properties: Tatabu is a very heavy and hard timber. Its basic specific gravity (oven-dry weight/green volume) is 0.78, with an air-dry density of 58 pcf (approximately 929 kg/m³). Other reports indicate a density of 1.20 kg/m³ (dry) and 910 kg/m³ (12% MC), with a basic specific gravity range of 0.85-0.97. The Janka hardness is 2,140 lb at 12% MC, and 1,980 lb for green material. The Monnin hardness is 9.4. The average toughness is 201 in.-lb. Shrinkage from green to oven-dry is radial 4.6-4.9% and tangential 7.0%, with volumetric shrinkage around 11.8%. The wood’s stability is rated as moderately stable to poorly stable.
Mechanical Properties: Tatabu exhibits outstanding strength properties, being described as very hard, heavy, tough, and strong. Its bending strength (Modulus of Rupture, MOR) is 213 N/mm² at 12% MC, and static bending strength is 141 MPa (dry). The modulus of elasticity (MOE) is 23630 N/mm² at 12% MC 1, and 22300 MPa (dry). Crushing strength is 110 N/mm² at 12% MC, and ranges from 78-98 MPa (dry). These properties underscore its suitability for demanding applications.
Uses: Tatabu is highly suitable for heavy construction work, including piling, piers, lock gates, and dock and harbor works. It is also valuable for boatbuilding, house framing, and flooring. Its strength properties make it suitable for engineering applications, such as bearers for engines, and for chemical plants, including vats, filter press plates, and frames. Other uses include furniture, turnery, tool handles, agricultural tools, vehicles, and railroad crossties. It can also be used for sliced veneer, interior and exterior paneling, and bridges (parts not in contact with water or ground).