Silver ash

Scientific name

Flindersia bourjotiana, F. schottiana. Family: Rutaceae.

Local names

Queensland silver ash (F. bourjotiana only), northern silver ash, southern silver ash, cudgerie, bumpy ash

Description and natural occurrence

A medium-sized, slim boled tree attaining a height of 35 m and 1 m stem diameter. The trunk is usually well formed and circular in cross-section. The bark, which is approximately 15 mm thick, is fairly smooth or finely warted. The tree can usually be recognised by swellings on the tree bole covering overgrown circles of broken-off limbs, giving it the local name of 'bumpy ash'.

It is distributed mainly in the rainforest areas of northern New South Wales, and southern and northern Queensland.

F. bourjotiana - Mt Fox (south-west of Ingham) to Cooktown

F. schottiana - northern New South Wales to Gladstone; areas of the Atherton Tableland

Wood appearance

Colour
The heartwood ranges from silver-white to pale yellow shades. There is no noticeable colour difference between sapwood and heartwood.

Grain
Open and predominantly straight. Slight grain deviation may occur associated with bumps on the log surface. There is no pronounced figure but a characteristic of the species is its long straight vessel lines on longitudinal surfaces.

Wood properties

Density. 640-675 kg/m3 at 12 per cent moisture content; approximately 1.5 m3 of seasoned sawn timber per tonne

Strength groups. S4 unseasoned; SD5 seasoned

Stress grades. F7, F8, F11, F14 (unseasoned); F8, F11, F14, F17 (seasoned), when visually stress graded in accordance with AS 2082:2000, Timber - hardwood - visually stress-graded for structural purposes

Joint groups. J3 unseasoned; JD3 seasoned

Shrinkage to 12% MC. F. bourjotiana: 5.5% (tangential); 3.0% (radial). F. shottiana: 4.8% (tangential); 3.1% (radial)

Unit shrinkage. 0.29-0.31 per cent (tangential); 0.20-0.21 per cent (radial), respectively. These values apply to timber reconditioned after seasoning

Durability above-ground. Class 3 - life expectancy 7 to 15 years

Durability in-ground. Class 3 - life expectancy 5 to 15 years

Lyctine susceptibility. Untreated sapwood susceptible to lyctid borer attack

Termite resistance. Not resistant

Preservation. Sapwood readily accepts preservative impregnation but penetration of heartwood is negligible using currently available commercial processes.

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

Hardness. Firm (rated 4 on a 6-class scale) in relation to indentation and ease of working with hand tools

Machining. Machines and turns well to a smooth surface

Fixing. No difficulty has been experienced with the use of standard fittings and fastenings

Gluing. Can be satisfactorily bonded using standard procedures

Finishing. Will readily accept stain, polish and paint

Uses

Decorative. Furniture, plywood, laminated beams, laminated bench tops, shop and office fixtures, flooring, lining, joinery, mouldings, parquetry flooring, turnery, carving, picture frames

Others. Boat building, marine plywood, structural plywood, coach, vehicle and carriage building, aircraft construction. Has been used for tool handles (axe, adze, pick), scaffold planks, sporting goods (baseball bats, archery bows, billiard cues, cricket stumps, skis), bentwork, draughtsperson´s implements, gun stocks, drum sticks, dowelling, fishing rods, boat oars, walking sticks, brush stock, broom handles

Identification features

General characteristics

Sapwood. Creamy-white to pale yellow, indistinguishable from the heartwood.

Heartwood. Creamy-white to pale yellow.

Texture. Medium and uniform, without figure but possessing a sheen.

Wood structure

Growth rings. Absent.

Vessels. Medium to small in size, arranged in short radial multiples; sometimes containing yellowish deposits. Vessel lines visible on longitudinal surfaces.

Parenchyma. Mostly in irregularly spaced apotracheal bands.

Rays. Visible without a lens.

Other features

Burning splinter test. Match size splinter burns to a full white ash.

Further reading

Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD (2006). Forest trees of Australia. CSIRO, Australia.

Bootle, K (2005). Wood in Australia. Types, properties and uses, (2nd edition). The McGraw-Hill Companies.

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.

Standards Australia (2000). AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes. Australian Standard. Distributed by SAI Global Limited.

Last updated 30 July 2010