White cypress pine is a softwood widely distributed in inland areas of Australia with moderate rainfall. Today it forms extensive forests only in the Tambo-Dalby-Inglewood region of southern Queensland and the Baradine-Narrabri and Cobar districts of northern New South Wales. White cypress pine is a small to medium-sized tree, usually growing to about 18 m tall and 0.45 m in diameter at breast height, but occasionally reaching 30 m by 0.9 m.
Heartwood is light-yellow to dark-brown and has frequent dark-brown knots, and sapwood is pale yellow and wide. The texture is very fine and even and grain is straight. The wood has a characteristic resinous odour and has a slightly greasy feel.
Green density is the density of wood in the living tree, defined as green mass divided by green volume, and useful for estimating transport costs. It varies with season and growing conditions.
Air-dry density is the average mass divided by volume at 12 per cent moisture content (this is the average environmental condition in the coastal capital cities around Australia).
Basic density is oven-dry mass divided by green volume. This measure has the advantage that moisture content variations in the tree during the year are avoided.:
Green density is about 770 kg/m3, air-dry density about 680 kg/m3, and basic density about 580 kg/m3.
Tangential and radial shrinkage of mature wood before reconditioning are 2.8 % and 2.1 % respectively, and after reconditioning both are 2.1 %. For immature wood, tangential and radial shrinkage before reconditioning are 3.6 % and 2.9 % respectively, and after reconditioning 3.2 % and 2.9 % respectively.
With workability, the timber is brittle and care is needed when working. Knots and resin are common, which can affect workability. It is inadvisable to dress timber at low moisture contents because of its brittleness, and it tends to split when nailed and pre-drilling is recommended. Owing to its susceptibility to fine surface checking, white cypress pine is one timber which gives a better painting performance when coated in the unseasoned condition, and by slowing the initial drying rate the coating inhibits the formation of checks. The timber is unusual in that both sapwood and heartwood are very difficult to impregnate with preservatives, even when high pressures are applied.
The CSIRO Durability Classes are based on the performance in ground of outer heartwood when exposed to fungal and termite attack.
|1||More than 25|
|2||15 to 25|
|3||8 to 15|
|4||Less than 8|
The ratings are not relevant to above-ground use. In late 1996, CSIRO published revised ratings, which include termite susceptibility. Ratings are now available for about seventy species for decay, and for decay plus termites.:
Durability Class based on the CSIRO 1996 ratings is 2 for decay, and 2 for decay + termites combined. The sapwood is resistant to Lyctus borer attack because the insects do not attack softwoods, only pored species.
Minimum values (MPa) for strength groups for green and seasoned timber come from Australian Standard AS2878-1986 'Timber - Classification of strength groups'. In grading structural timber, each species is allocated a ranking for green timber of S1 (strongest) to S7, and for seasoned timber SD1 (strongest) to SD8.
MOR is modulus of rupture or bending strength, MOE is modulus of elasticity or 'stiffness', and MCS is maximum crushing strength or compression strength. Hardness refers to the Janka hardness test and is a measure of resistance to indentation.
Minimum values (Mpa) for green timber
Minimum values (Mpa) for green timber
Where test data were available, they are shown in bold print. Most values are from Bootle (1983), Wood in Australia. Types, properties and uses. (McGraw-Hill), or Julius (1906), 'Western Australian timber tests 1906: The physical characteristics of the woods of Western Australia'.
Where no strength data were available, air-dry density was used in accordance with the Australian Standard AS2878-1986 Timber - Classification of strength groups to predict the strength group. Consequently, the strength values quoted are from the above two tables.:
Green and seasoned strength groups are S5 and SD6 respectively. The more important strength properties are given in the table below.
|Modulus of Rupture||MPa||71||79|
|Modulus of Elasticity||MPa||7700||9000|
|Max Crushing Strength||MPa||40||53|
There is very limited availability in Western Australia, although other species are readily available in other States.
Uses are flooring and lining boards, building framework, posts and small poles. The wood is not favoured for paper manufacture owing to frequent knots and high extractives content.