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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

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.