Milk Tree - Antiaris toxicaria
Milk Tree is a magnificent deciduous tree of the forest canopy, often 20 to 40 metres tall with a dome shaped crown. The tree yields a lightweight hardwood with density of 380-420 kilograms per cubic metre. As the wood peels very easily and evenly, it is commonly used for veneer production.
- The timber has wide sapwood that is not clearly demarcated from heartwood which is usually white but may be brownish. There is a distinct ribbon figure on quarter-sawn faces. The grain may be straight to interlocked, but is typically moderately interlocked. Annual rings are usually not discernible since the tree is reported to grow evenly all year round.
- Trees must be converted rapidly after felling to avoid deterioration and must be protected against blue stain. It seasons readily and quickly. Kilning gives best results, with minimal warping and splitting. There is moderate shrinkage upon seasoning but it is very stable after seasoning.
- Can be worked fairly easily with hand and machine tools, but cutting edges must be very sharp to avoid tearing and crumbling. The dust from Milk Tree is toxic because of the latex that is present causing dermatitis and stomach pains.
- Milk Tree is used for high structural, boat building, cabinet & furniture, joinery, mouldings and paneling, fruit cases, light framing. It is also said to slice into attractive, quartered striped veneers for decorative applications.
Names
Family:
Moraceae
Species:
Antiaris toxicaria
Standard Trade Names:
Milk Tree
Other Names:
Melektri (Vanuatu) Bark Cloth Tree (U.K) upas (Philippines)
PROPERTIES
Density:
380-420 Kg/m3 @ 12% m.c
Colour:
White and sometimes can be brownish.
Texture:
Even medium to coarse.
Grain:
Interlocked and wavy.
Figure:
Lustrous, ribbon figure on quarter-sawn faces.
Durability:
Class 4: Non-durable
Permeability:
Class 1: Permeable to pressure impregnation
WORKABILITY
General:
Very soft and easy to work with if blades are kept sharp.
Sawing:
Saws easily but is slightly gummy because of latex.
Planing:
Planing requires a cutting angle of 20 degrees to prevent interlocked grain from tearing out.
Blunting:
Low
Boring:
The wood is fairly difficult to bore because of interlocked grain and soft fibrous tissue. Support is required to prevent break-out as tool exits.
Turning:
Nailing:
Nails satisfactorily.
Gluing:
Glues well.
Finishing:
Polishes well, accepts stain and paint satisfactorily.
MECHANICAL PROPERTIES
Strength:
SD8
Structural Grade:
F11 (select grade seasoned).
Hardness(Janka):
3.8kN (seasoned), 2.7kN (unseasoned).
Max. Crushing Strength:
46MPa (seasoned), 25Mpa (unseasoned).
Modulus of Elasticity:
12GPa (seasoned), 9.7GPa (unseasoned).
Modulus of Rupture:
85MPa (seasoned), 49MPa (unseasoned).
SEASONING
General:
Seasons rapidly.
Movement:
Very low
Shrinkage:
Low
