Mukulungu

Mukulungu

Mukulungu

TRADE NAME : Mukulungu

SCIENTIFIC NAME : Autranella congolensis A.Chev. 
  • BOTANICAL DESCRIPTION :  The tree reaches a height of 40 and more. The bole is straight, cylindrical and clear to long lengths. The trunk diameter attains from 130 cm up to 200 cm and is sometimes buttressed.
  • NATURAL HABITAT : Autranella congolensis occurs in the dense equatorial forests of Africa.
  • NATURAL DISTRIBUTION : Widely distributed throughout the dense equatorial forests of Africa.

WOOD DESCRIPTION

  • Color : The sapwood is greyish, it has a thickness of 2 to 3 cm. The heartwood is red brown, with darker markings, it is clearly demarcated. The silver figure is fine (barely visible).
COLOR INDEX (1=BLACK, 7=LIGHT YELLOW,WHITE)4
  • GRAIN :  Straight or slightly interlocked, sometimes with an influence on further processing operations.
  • TEXTURE :Texture is usually fine to medium.

  • LUSTER : The wood is described as low in luster.

  • NATURAL DURABILITY : Very durable to decay; without preservative treatment. This species is especially suited for all the uses with risks of permanent or long-lasting humidification. Resistant to termites attack. Heartwood is resistant to Lyctus attacks.

  • NATURAL DURABILITY INDEX (1= VERY HIGH DURABILITY, 7=VEY LOW DURABILITY)1

  • INTERNAL GROWTH STRESSES : Residual stresses are reported to be absent.
  • RESISTANCE TO IMPREGNATION : Difficult to treat with only a low penetration of the preservative products.

WOOD PHYSICAL PROPERTIES

BASIC DENSITY OR SPECIFIC GRAVITY (O.D. WEIGHT/VOL. GREEN) (G/CM°) 0.82 AIR-DRY DENSITY (WEIGHT AND VOLUME AT 120/oM ) (G/CM°)0.94
TOTAL SHRINKAGE TANGENTIAL (SATURATED TO 00/oM ) (0/o)8.4 TOTAL SHRINKAGE RADIAL (SATURATED TO 00/oM ) (0/o)7. 4

DRYING DEFECTS : Ease of Drying: Drying is rather slow and sometimes difficult to perform. Drying Defects: Risks of checks and distortions. Kiln Schedules: Schedule proposed as a reference by comparison with well known species taking into account to the general technological behavior of this species.
RECOMMENDED DRY KILN SCHEDULE FR-9
DIMENSIONAL STABILITY RATIO (TOTAL TANGENTIAL SHRINKAGE 0/o/TOTAL RADIAL SHRINKAGE 0/o) 1.1

WOOD MECHANICAL PROPERTIES

BENDING STRENGTH (MOR),120/oM (KGF/CM 2) 1211 STIFFNESS (MOE) 120/oM (KGF/CM 2)173910 COMPRESSION PARALLEL TO FIBER 120/oM (KGF/CM 2)757
COMPRESSION PERPENDICULAR TO FIBER 120/oM (KGF/CM 2)108 SHEAR STRENGTH RADIAL 120/oM (KGF/CM 2)91 JANKAHARDNESS (SIDE) 120/oM (KGF)1111
JANKAHARDNESS (END GRAIN) 120/oM (KGF)1137

WORKABILITY

  • SAWING : Sawing of this species requires powerful equipment.
  • ROTARY VENEER CUTTING : Suitable for slicing
  • SLICED VENEER :Suitable for slicing
  • BLUNTING EFFECT :  Severe blunting effect; stellited blades for sawing and carbide tools for machining are recommended.
  • MACHINING:  It needs powerful tools for processing. Possible difficulties caused by interlocked grain are reported.
  • PLANING: Moderately easy; tools must be cautiously sharpened.
  • MOULDING: Easy; no particular problems.
  • TURNING 30
  • BORING: Easy; no particular problems.
  • MORTISING: Easy; no particular problems.
  • NAILING :Pre-boring is necessary.
  • GLUING : Difficult to glue because of high density.
  • SANDING: Easy to perform; it gives good results.
  • POLISHING : Can be polished without surface preparation.
  • RESPONSE TO HAND TOOLS:Working with hand tools is difficult.

END USES:

EXTERIOR GENERAL, bridges, poles, rails, crossarms, crossties, piers, HOUSING GENERAL, beams, joists, boards, flooring, parquet, frames, steps, panelling, fittings, PLYWOOD AND VENEER, Decorative veneer, CONTAINERS, cooperage, truck bodies, truck flooring