Yellow stringybark in its natural occurrence is commonly a tall tree 25-40 m in height and up to 1 m diameter ( dbh). On favourable sites, it may be 50 m in height and 3 m dbh. This species occurs on coastal plains and adjacent ranges in southeastern Australia from near Wollongong, New South Wales, in the north to Wilson's Promontory in Victoria. Yellow stringybark typically occurs in tall open-forest formation. Trial plantings have been established in south-west Western Australia for use as power poles.
Heartwood is a light yellowish brown with a pinkest tinge. Sapwood is very pale brown, to 2.5 cm thick, and the texture is medium and even with grain interlocked.
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 1100 kg/m3, air-dry density about 870 kg/m3, and basic density about 695 kg/m3.
Tangential and radial shrinkage before reconditioning are 7.5 and 4.3 per cent respectively, and after reconditioning 5.5 and 3.2 per cent respectively.
With workability, the timber needs care in drying to minimise checking and splitting. It is a hard and heavy timber to work.
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 1996 CSIRO assessment is 3 for decay, and 4 for decay + termites combined.
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 dry strength groups are S3 and SD3 respectively. The more important strength properties are given in the table below.
|Modulus of Rupture||MPa||90||132|
|Modulus of Elasticity||MPa||14000||17000|
|Max Crushing Strength||MPa||44||72|
The timber is not readily available in Western Australia, but is common on the south coast of New South Wales.
Use as power poles was the original objective of planting the species in Western Australia, but flooring has great potential. Previous uses in the eastern states include general construction, posts, poles, bridge timber, sleepers and cross arms.