Silver Ash (Flindersia schottiana): A Resilient Rainforest Tree with Exceptional Timber Qualities
Silver Ash (Flindersia schottiana), also known as Cudgerie, Bumpy Ash and Southern Silver Ash, is a rainforest tree native to eastern Australia and New Guinea. It produces a pale timber used in Australian woodworking and decorative design. [1][3]
What Is Silver Ash?
In the Australian timber trade, both F. schottiana and Flindersia bourjotiana are grouped under the commercial name Silver Ash, with F. bourjotiana also known as Queensland Silver Ash. This page refers specifically to Flindersia schottiana. [3]
Southern Silver Ash is another recognised common name for F. schottiana. [1]
Where Does Silver Ash Grow?
Flindersia schottiana is native to eastern Queensland, northeastern New South Wales and New Guinea. In New South Wales it occurs in lowland subtropical and littoral rainforest north from the Hastings River. [1][2]
The species has been recorded from near sea level to about 1,000 metres. In Cape York Peninsula and northeastern Queensland it also occurs in drier, more seasonal rainforest and can grow in association with Kauri Pine (Agathis robusta). [4]
Silver Ash is also a documented larval food plant of the Orchard Butterfly. [4]
How to Identify a Silver Ash Tree
Silver Ash can reach about 50 metres in height. The trunk often develops scattered bumps or burls, a characteristic reflected in the alternative common name Bumpy Ash. These swellings can form where broken branches have been overgrown. [1][3]
The compound leaves usually carry 7 to 19 leaflets. Their upper surfaces are shiny dark green, while the undersides are greyer, and numerous oil dots are visible in the leaves. [1]
White flowers appear from late spring into early summer. [1]
The flowers are followed by woody capsules about 8 to 13 centimetres long that split when mature, releasing seeds winged at both ends. [1]
What Does Silver Ash Timber Look Like?
Silver Ash heartwood ranges from silver-white to pale yellow, with little visible colour difference between the heartwood and sapwood. [3]
The grain is open and predominantly straight, although deviations can occur around the characteristic swellings in the trunk. The texture is generally medium and relatively uniform. [3]
Silver Ash Timber Properties
| Property | Silver Ash |
|---|---|
| Air-dry density | Approx. 690 kg/m³ at 12% moisture content |
| Natural durability | Class 3 above ground and in ground* |
| Termite resistance | Not resistant* |
| Machining | Machines and turns well* |
| Gluing | Bonds satisfactorily using standard procedures* |
| Seasoning | Dries satisfactorily using conventional air and kiln seasoning* |
Source note: The density figure is reported specifically for Flindersia schottiana. [5] The remaining technical properties come from the broader Australian commercial Silver Ash profile covering both species. The same profile records untreated sapwood as susceptible to lyctid borer attack. [3]
What Is Silver Ash Timber Used For?
Documented uses of Silver Ash include furniture, cabinetry, interior joinery, flooring, parquetry, mouldings, panelling, plywood, veneer, turning, carving, picture frames and boatbuilding applications. [3][5]
Flindersia schottiana has also been used historically for cooperage, cricket stumps, billiard cues and tool handles. The species has been described as producing a very pale cabinet timber capable of taking a high polish. [4]
Cudgerie in Australian Design
Cudgerie was among the Australian native timbers used in commissioned marquetry at Parliament House. Flindersia schottiana appears in works by Tony Bishop and Michael Retter in areas including the Marble Foyer and Cabinet Suite. [6]
Silver Ash at Australian Woodwork
The Tubb Cheeseboard is made from changing combinations of Australian timbers that may include Silver Ash. Because the timber selection varies between boards, Silver Ash is not present in every example. [10]
The Jarrah and Ash Deco Wall Clock uses a Silver Ash clock face surrounded by a contrasting Jarrah frame. [11]
Growth and Propagation
Fresh Flindersia schottiana seed has a recorded germination period of approximately 6 to 14 days. [4]
Australian rainforest reforestation research found that F. schottiana did not fruit every year and could produce relatively modest quantities of seed when fruiting occurred. In vegetative propagation trials involving five Flindersia species, F. schottiana produced the highest result but still achieved only 14% rootability from cuttings. [9]
Silver Ash in Plantation Research
Queensland plantation trials recorded a mean annual height increment of 1.41 metres per year for F. schottiana, with 93% survival among measured trees. Performance varied substantially between sites, with mean annual height increments ranging from 0.44 to 2.09 metres per year. [9]
A study of mixed-species cabinet timber plantations in northern New South Wales found F. schottiana and F. brayleyana among the more consistent species across sites, while also identifying strong interactions between species performance and individual site conditions. [8]
In a separate study comparing six Australian rainforest tree species under 10%, 30% and 60% of full sunlight, F. schottiana was among the secondary-stage species with higher relative growth rates than the mature-stage rainforest species included in the experiment. [7]
Is Silver Ash Endangered?
No. Kew Plants of the World Online reports Flindersia schottiana as Least Concern under the IUCN conservation assessment. [2]
References
- PlantNET, Royal Botanic Garden Sydney. Flindersia schottiana F.Muell., New South Wales Flora Online
- Royal Botanic Gardens, Kew. Flindersia schottiana F.Muell., Plants of the World Online
- Business Queensland. Silver ash: Flindersia bourjotiana, F. schottiana — timber properties and uses
- Australian Tropical Rainforest Plants, CSIRO. Flindersia schottiana F.Muell.
- International Tropical Timber Organization. Silver Ash — Flindersia schottiana
- Parliament of Australia. The natural materials of Parliament House
- Kelly, J., Jose, S., Nichols, J. D., & Bristow, M. (2009). Growth and physiological response of six Australian rainforest tree species to a light gradient. Forest Ecology and Management, 257(1), 287–293. https://doi.org/10.1016/j.foreco.2008.09.008
- Specht, A., & Turner, J. (2006). Foliar nutrient concentrations in mixed-species plantations of subtropical cabinet timber species and their potential as a management tool. Forest Ecology and Management, 233(2–3), 324–337. https://doi.org/10.1016/j.foreco.2006.05.029
- Rainforest CRC / Australian rainforest reforestation research. Reforestation in the Tropics and Subtropics of Australia Using Rainforest Tree Species
- Australian Woodwork. Tubb Cheeseboard
- Australian Woodwork. Jarrah and Ash Deco Wall Clock