Northern cypress

Scientific name Callitris intratropica syn. C. columellaris var intratropica. Family name: Cupressaceae.
Local names

Cypress pine, blue cypress, northern Christmas tree, laguni (Waguni people), karntirrikani (Tiwi people).

Description and natural occurrence

Small to medium-sized, slow growing conifer, 20 to 30 m high. The foliage is blue-green to dark green.

Northern cypress occurs across northern Australia in a range of habitats with free draining (sandy) soils.

Plantation grown timber

Almost 3000 hectares of plantations were established in the Northern Territory mainland and several sourrounding islands during the 1960s and 1970s.

Wood appearance

Colour. The heartwood is pale yellow to streaky gold and brown. The sapwood is white-pale yellow. As with other cypress timbers, knots are a feature.

Grain. Generally fine and even, occasionally interlocked, producing an attractive figure.

Wood properties

Density. 675 kgm3 at 12% moisture content; approximately 1.5 m3 of seasoned sawn timber per tonne.

Strength groups. S4 unseasoned; SD5 seasoned.

Stress grades. F4, F5, F7 (seasoned and unseasoned), when visually stress graded in accordance with AS 2858-1986, Timber - softwood - visually graded for structural purposes.

Joint groups. J3 unseasoned; JD3 seasoned.

Shrinkage to 12% MC. 2.8% (tangential); 2.1% (radial).

Unit shrinkage. 0.22% (tangential); 0.18% (radial), low shrinkage, very stable timber.

Durability above-ground. Class 1 (provisionally) - life expectancy over 40 years.

Durability in-ground. Class 1 - life expectancy 15 to 25 years. Heartwood highly resistant to decay when fully exposed to the weather and/or used in the ground.

Lyctine susceptibility. Not susceptible.

Termite resistance. Resistant to subterranean termites.

Preservation. Negligible penetration of heatwood and sapwood using current commercial processes.

Seasoning. Can be satisfactorily dried using conventional air and kiln seasoning methods.

Hardness. Firm in relation to indentation and ease of working with hand tools.

Machining. Machines well.

Fixing. Pre-drilling recommended prior to hand nailing seasoned timber to prevent splitting.

Gluing. Roughing the surface may enhance the strength of the bond.

Finishing. Will readily accept paint, stain and polish.

Uses

Construction. Used as sawn timber in general house framing, internal and external flooring, linings, joinery fencing.

Decorative. Internal furniture, outdoor furniture, turnery.

Others. Beehives, oyster stakes, essential oil (Autralian blue cypress, blue cypress oil).

Further reading

Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, 'Forest trees of Australia', 5th edn, CSIRO Publishing, Collingwood Australia.

Bootle, K 2005, 'Wood in Australia: types, properties and uses', 2nd edn, McGraw-Hill, Sydney.

Hopewell, G (ed.) 2006, 'Construction timbers in Queensland: properties and specifications for satisfactory performance of construction timbers in Queensland, Class 1 and Class 10 buildings', books 1 and 2, Department of Primary Industries and Fisheries, Brisbane.

Ilic, J 1991, 'CSIRO atlas of hardwoods', Crawford House Press, Bathurst, Australia.

Standards Australia, 2000, 'AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes', Standards Australia.

Last updated 25 August 2010