White cheesewood
Scientific name
Alstonia scholaris; A. actinophylla; Wrightia laevis ssp. Millgar. Family: Apocynaceae
Other names
Milky pine; milkwood
Description
- Medium to large tree, grows to 35m high.
- Stem grows to 1m diameter.
- Bark is light grey to grey, and when cut is yellowish brown and exudes a large quantity of milky sap.
Occurrence
- Widely distributed in Queensland from near Sarina to Thursday Island.
- Occurs in:
- New Guinea
- Southeast Asia
- India
- Sri Lanka.
Appearance
Colour
- Heartwood is white to cream.
- Very wide sapwood zone, which is visually indistinct from the heartwood.
Grain
- Medium to coarse texture.
- Straight grain.
Uses
- Construction: plywood centre veneers, mouldings, lining, treated fascia and barge boards.
- Decorative: carving, turnery.
- Others: previously used for pattern-making.
Properties
- Density: A. scholaris—400 kg/m3, A. actinophylla—385 kg/m3 and W. laevis ssp. millgar—335 kg/m3 at 12% moisture content; about 2.5m3 of seasoned sawn timber per tonne.
- Strength groups: A. scholaris—S7 unseasoned, SD8 seasoned; A. actinophylla—(S7) unseasoned, (SD8) seasoned; W. laevis ssp. Millgar—(S<7) unseasoned, (SD<8) seasoned (brackets indicate provisional value).
- Stress grades: F4, F5, F7, (unseasoned); F4, F5, F7, F8 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded hardwood for structural purposes.
- Joint groups: A. scholaris and A. actinophylla—J5 unseasoned, JD5 seasoned; W. laevis ssp. Millgar—JD6 seasoned.
- Shrinkage to 12% MC: 4.0% (tangential), 2.5% (radial).
- Unit shrinkage: not available.
- Durability above-ground: Class 4 (life expectancy less than 7 years).
- Durability in-ground: Class 4 (life expectancy less than 5 years).
- Lyctine susceptibility: susceptible.
- Termite resistance: not resistant.
- Preservation: sapwood readily impregnates with preservative, impregnation but penetration of heartwood is negligible using available commercial processes.
- Seasoning: can be satisfactorily dried using conventional air and kiln seasoning; very susceptible to blue stain.
- Hardness: very soft (rated 6 on a 6-class scale) to indent and work with hand tools.
- Machining: will dress and mould to a smooth finish with sharp blades and cutters.
- Fixing: no difficulty using standard fittings and fastenings.
- Gluing: satisfactorily bonds using standard procedures.
- Finishing: readily accepts paint, stain and polish, but you may need to fill the coarse texture before painting or polishing.
Identification features
General characteristics
- Sapwood: indistinguishable in colour from heartwood.
- Heartwood: cream to white.
- Texture: medium texture, uniform.
Wood structure
- Vessels: medium to large, elliptical, visible without a lens; mostly solitary but numerous radial pairs, may occur in multiples of 3 or more, or occasionally in clusters; obvious vessel lines on longitudinal surfaces.
- Parenchyma (soft tissue): visible as numerous fine, wavy apotracheal rows spaced about 2 per mm.
- Rays: fine to medium, readily visible with a lens.
Other features
- Burning splinter test: match-size splinter burns to a thin partial ash. Latex canals: may contain elongated radial pockets or latex canals as a feature; jelutong, a very similar imported species, can be distinguished by more closely packed parenchyma and radial canals within the rays.
Research and resources
- Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, Forest trees of Australia, 5th ed., CSIRO Publishing, Collingwood, Australia.
- Bootle, K 2005, Wood in Australia: Types, properties and uses, 2nd ed., McGraw-Hill, Sydney.
- Ilic, J 1991, CSIRO atlas of hardwoods, Crawford House Press, Bathurst, Australia.