Scientific Name
Mitragyna rubrostipulacea
Trade Name
Abura
Family Name
Rubiaceae
Synonyms
Mitragyna rubrostipulata, Mitragyne rubrostipulacea, Mitragyne rubrostipulata, Adina rubrostipulata, Hallea rubrostipulata
Common Names
Abura, Mromberomba, Mromberombbe, Muho, Munyzmaizi, Mutoro, Mutororo, Muzingu, Nazingu, Ngomera, Nzin, Nzingu, Obul, Omuzito, Oo, Romberombe
Regions of Distribution
Africa
Countries of Distribution [VIEW MAP]
Tanzania, Uganda
Common Uses
Boxes and crates, Cabinetmaking, Carvings, Flooring, Furniture, Joinery, Light construction, Moldings, Plywood corestock, Plywood, Pulp/Paper products, Toys, Vats, Veneer, Veneer: decorative
Heartwood Color
| Yellow | ||||||||||||
| Brown | ||||||||||||
| Orange | ||||||||||||
| Red | ||||||||||||
| Pale red to pink | ||||||||||||
| Pale brown | ||||||||||||
| Brown | ||||||||||||
| White to cream |
Sapwood Color
| White | ||||||||||||
| Yellow |
Grain
| Straight | ||||||||||||
| Figure | ||||||||||||
| Weak (figure) | ||||||||||||
| Even | ||||||||||||
| Growth rings (figure) |
| Straight | ||||||||||||
| Weak figure | ||||||||||||
| Clear growth rings (figure) |
Texture
| Fine | ||||||||||||
| Medium | ||||||||||||
| Fine | ||||||||||||
| Fine to medium |
Luster
| Dull |
Natural Durability
| Durable | ||||||||||||
| Perishable | ||||||||||||
| Non-durable | ||||||||||||
| Susceptible to insect attack | ||||||||||||
| Non-resistant to powder post beetles | ||||||||||||
| Non-resistant to termites | ||||||||||||
| Non-resistant to marine borers | ||||||||||||
| Perishable | ||||||||||||
| Susceptible to attack from termites (Isoptera) | ||||||||||||
| Non durable | ||||||||||||
| Susceptible to attack from powder post (Lyctid & Bostrychid) beetles | ||||||||||||
| Pinworms (ambrosia beetles) are commonly present | ||||||||||||
| Moderately durable |
Toxicity
| Some toxic effects |
Kiln Schedules
| Dry at a slow speed | ||||||||||||
| Kiln Drying Rate (in days) is fairly rapid | ||||||||||||
| Drying (speed) is fast | ||||||||||||
| UK=K US=T13C4S/T11D3S | ||||||||||||
| UK=H US=T10D4S/T8D3S Fr=7 | ||||||||||||
| UK=C US=T3C2/T3C1 Fr=3 |
Drying Defects
| Splitting | ||||||||||||
| Moderate end spitting | ||||||||||||
| Slight end splitting | ||||||||||||
| Moderate cupping | ||||||||||||
| Slight twist/warp | ||||||||||||
| No twisting or warping | ||||||||||||
| No surface checking | ||||||||||||
| Slight surface checking | ||||||||||||
| Slight cupping |
Ease of Drying
| Fairly Easy | ||||||||||||
| Rapidly | ||||||||||||
| Easy |
Kiln Drying Rate
| Naturally dries quickly | ||||||||||||
| Rapid (<10 days for boards < 32 mm, to <30 days for boards >= 63 mm) |
Tree Identification
| Bole/stem form is buttressed | ||||||||||||
| Bole/stem form is not buttressed |
Tree Size
| Tree height is 20-30 m | ||||||||||||
| Bole length is 10-20 m | ||||||||||||
| Bole length is 0-10 m |
Blunting Effect
| Blunting effect on machining is slight |
Cutting Resistance
| Easy to saw | ||||||||||||
| Cutting Resistance with green wood is easy | ||||||||||||
| Cutting Resistance with dry wood is easy |
Gluing
| Fairly Easy to Very Easy | ||||||||||||
| Easy to glue |
Moulding
| Good finishing results |
Movement in Service
| Excellent Stability – Small Movement | ||||||||||||
| Medium | ||||||||||||
| Small |
Nailing
| Fairly Easy to Very Easy | ||||||||||||
| Easy to nail | ||||||||||||
| Holds satisfactorily |
Planing
| Good planing finish |
Resistance to Impregnation
| Resistant heartwood | ||||||||||||
| Resistant sapwood | ||||||||||||
| Heartwood is permeable | ||||||||||||
| Sapwood is permeable | ||||||||||||
| Heartwood is moderately resistant |
Response to Hand Tools
| Easy to Work | ||||||||||||
| Easy to machine |
Screwing
| Fairly Easy to Very Easy |
Turning
| Difficult to turn |
Veneering Qualities
| Veneers easily | ||||||||||||
| Veneers moderately easy | ||||||||||||
| Suitable for peeling | ||||||||||||
| Easy to cut |
Steam Bending
| Fair to Good Results | ||||||||||||
| Very Good to Excellent Results |
Painting
| Good results |
Polishing
| Very Good to Excellent Results | ||||||||||||
| Fair to Good Results | ||||||||||||
| Satisfactory results | ||||||||||||
| Good results |
Staining
| Finish is generally satisfactory | ||||||||||||
| Finish is generally good |
Strength Properties
| Density (dry weight) = 31-37 lbs/cu. ft. | ||||||||||||
| Shrinkage, Radial = small | ||||||||||||
| Shrinkage, Radial = fairly large | ||||||||||||
| Max. crushing strength = medium | ||||||||||||
| Bending strength (MOR) = low | ||||||||||||
| Toughness-Hammer drop (Impact Strength) = low | ||||||||||||
| Shrinkage, Radial = moderate | ||||||||||||
| Shearing strength (parallel to grain) = very low | ||||||||||||
| Modulus of Elasticity (stiffness) = low | ||||||||||||
| Hardness (side grain) = soft | ||||||||||||
| Shrinkage, Radial = very small | ||||||||||||
| Shrinkage, Radial = large | ||||||||||||
| Density (dry weight) = 38-45 lbs/cu. ft. | ||||||||||||
| Density (dry weight) = 23-30 lbs/cu. ft. | ||||||||||||
| Shrinkage, Tangential = moderate |
Numerical Data
| Item | Green | Dry | English |
| Bending Strength | 6111 | 9589 | psi |
| Density | 33 | lbs/ft3 | |
| Hardness | 995 | lbs | |
| Impact Strength | 28 | inches | |
| Maximum Crushing Strength | 3916 | 6397 | psi |
| Shearing Strength | 882 | psi | |
| Stiffness | 1358 | 1568 | 1000 psi |
| Weight | 32 | 25 | lbs/ft3 |
| Radial Shrinkage | 4 | % | |
| Tangential Shrinkage | 7 | % | |
| Item | Green | Dry | Metric |
| Bending Strength | 429 | 674 | kg/cm2 |
| Density | 528 | kg/m3 | |
| Hardness | 451 | kg | |
| Impact Strength | 71 | cm | |
| Maximum Crushing Strength | 275 | 449 | kg/cm2 |
| Shearing Strength | 62 | kg/cm2 | |
| Stiffness | 95 | 110 | 1000 kg/cm2 |
| Weight | 512 | 400 | kg/m3 |
| Radial Shrinkage | 4 | % |
References
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.,1967,Commercial Timbers of Tanzania,Tanzanian Forestry Division Util. Sec. Moshi
Eggeling, W.J.,1940,Indigenous Trees of Uganda,Govt. Printer Entebbe Uganda
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
Grant, D.K.S.,1934,Some Local Timbers,Tanzania Forest Department
Murira, K.,1984,Natural Durability Tests of Tanzanian Timbers 1955 – 1982,Tanzania Forestry Research Institute, Timber Utilisation Research Centre,,Moshi.
Tack, C.H.,1969,Uganda Timbers,Govt. Printer Uganda
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 Forest Division,1966,Kiln Drying Schedules for Tanzania Timbers Technical Note no.38,Tanzania Forest Div. Util. Sec. Moshi
Tanzania Forest Division,1966,Mitragyna rubrostipulata (nzingu/mromberombe,Tanzania Forest Div. Util. Sec. Moshi – Timbers of Tanganyika
Uganda Forest Department,1954,Abura (Mitragyna stipulosa and Mitragyna rubrostipulata,Uganda Forest Div. Util. Sec. Timber Leaflet,No.6