Tulip oak
Scientific name
Argyrodendron actinophyllum ssp. actinophyllum, A. trifoliolatum, A. peralatum. Family: Sterculiaceae
Other names
Blush tulip oak; booyong; crowsfoot elm; blackjack (A. actinophyllum ssp. actinophyllum); brown tulip oak; highroot; stavewood; brown crowsfoot elm; brown oak; hickory (A. trifoliolatum); red tulip oak; red crowsfoot; red crowsfoot elm (A. peralatum)
Other tulip oaks include A. polyandrum, A. sp. aff. A. trifoliolatum, A. actinophyllum ssp. diversifolium, and A. sp. aff. A. peralatum
Other tulip oaks include A. polyandrum, A. sp. aff. A. trifoliolatum, A. actinophyllum ssp. diversifolium, and A. sp. aff. A. peralatum
Description
- Grows to 50m high.
- Bases of large trees are usually prominently buttressed.
- Leaves have white or silver on underside.
Occurrence
- Actinophyllum ssp. actinophyllum and A. trifoliolatum occur in scrubs and rainforests along the east coast of Australia.
- A. peralatum is restricted to North Queensland between Tully and Cooktown.
Appearance
Colour
- Heartwood is pink-brown for A. actinophyllum ssp. Actinophyllum, and brown for A. trifoliolatum. Sapwood not always readily distinguished.
- Heartwood pink to red-brown for A. peralatum, with whitish sapwood.
Grain
- Grain is usually straight and open, sometimes interlocked or wavy and irregular producing some beautifully figured (patterned) wood.
- Attractive figure on tangential face and large ray fleck on radial face are prominent features of the tulip oaks.
Uses
- Construction: flooring, green framing and plywood.
- Decorative: panelling, furniture, bent work, joinery, ornamental boxes, turnery and boat building.
- Others: handles, fishing rods.
Properties
- Density: 800–925kg/m3 at 12% moisture content; about 1.1 to 1.3m3 of seasoned sawn timber per tonne.
- Strength groups:
- A. actinophyllum ssp. Actinophyllum—S3 unseasoned, SD3 seasoned
- A. trifoliolatum—S2 unseasoned, SD2 seasoned
- A. peralatum—S3 unseasoned, SD4 seasoned.
- Stress grades when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes:
- A. actinophyllum ssp. actinophyllum F8, F11, F14, F17 (unseasoned); F14, F17, F22, F27 (seasoned)
- A. trifoliolatum F11, F14, F17, F22 (unseasoned); F17, F22, F27, F34 (seasoned)
- A. peralatum F8, F11, F14, F17 (unseasoned); F11, F14, F17, F22 (seasoned).
- Joint groups: J2 unseasoned, JD2 seasoned.
- Shrinkage to 12% MC:
- A. actinophyllum ssp. Actinophyllum—8.6% (tangential), 3.6% (radial)
- A. trifoliolatum—9.0% (tangential), 3.3% (radial)
- A. peralatum—8.9% (tangential), 4.4% (radial).
- Unit shrinkage:
- A. actinophyllum ssp. Actinophyllum—0.37% (tangential), 0.24% (radial)
- A. trifoliolatum—0.44% (tangential), 0.27% (radial)
- A. peralatum—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: untreated sapwood susceptible to lyctid borer attack.
- Termite resistance: not resistant.
- Preservation: difficult to impregnate with preservatives.
- Seasoning: dry carefully under cover to minimise degrade; you should partially air-dry before kiln-drying at low temperatures; prone to collapse if you dry too rapidly.
- Hardness: hard (rated 2 on a 6-class scale) to indent and work with hand tools.
- Machining: not easy to work, but peels well; causes moderately severe blunting of cutters; reduce the cutting angle to 20° when planing or moulding to avoid tearing the grain on quartered material.
- Fixing: you may need to pre-bore before nailing.
- Gluing: glues satisfactorily.
- Finishing: readily accepts paint, stain and polish.
Identification features
General characteristics
- Sapwood: not always easy to distinguish from the heartwood.
- Heartwood: pale light brown to red-brown and dark brown.
- Texture: medium to coarse, grain is mostly straight, occasionally interlocking.
Wood structure
- Vessels: solitary, and short radial chains of up to 4 cells or more, medium size with uniform distribution; vessel lines visible.
- Parenchyma (soft tissue): some paratracheal but mostly irregularly spaced apotracheal bands.
- Rays: just visible to the naked eye; 2 sizes—distinct and small; larger rays are very visible on radial surfaces.
Other features
- Burning splinter test: match-size splinter will burn (with some exudation and smoke) to a full white ash.
- Ripple marks: distinct in some species on smooth tangential surfaces.
- Figure (pattern): attractive figure on tangential dressed surfaces due to bands of parenchyma.
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.
- Queensland Government, DAF 2018, Construction timbers in Queensland: Properties and specifications for satisfactory performance of construction timbers in Queensland. Class 1 and Class 10 buildings, Books 1 & 2, Department of Agriculture and Fisheries, Brisbane.
- Standards Australia, 2000, AS 2082-2000: Timber—Hardwood—Visually stress-graded for structural purposes, Standards Australia International, Strathfield, NSW.