Silver wattle
Silver wattle (Acacia dealbata) is a very fast-growing acacia species that prefers high annual rainfall and deep clay loam soils. It is most often used as a nurse crop species.
Table 1: General characteristics for silver wattle
Characteristic | Description |
|---|---|
Botanical name | Acacia dealbata |
Growth rate in preferred conditions | Very fast |
Estimated rotation length (yr) in preferred conditions to produce 60cm diameter at breast height | 10–20 |
Preferred annual rainfall (mm/yr) | 1200+ |
Minimum rainfall (mm/yr) | 1000 |
Preferred elevation (m) ASL | 50–1000 |
Preferred landscape position | Valley, damp southern aspect |
Preferred soil | Deep clay loam |
Prohibitive soil | Deep sand or duplex |
Poor drainage tolerance | Low |
Dry site tolerance | Low |
Frost tolerance | Very high |
Pest and disease problems: | Fireblight larvae, longicorn borers |
Table 2: Timber characteristics for silver wattle
Characteristic | Description |
|---|---|
Strength: seasoned timber only | SD5: moderate/low |
Durability: in ground | above ground | 4 | 4 |
Drying: green to 12% moisture content | Shrinkage at about 2% radial and 5% tangential. Usually kiln dried after air drying. |
Main commercial products | Panelling, internal flooring, veneers, interior joinery, furniture, firewood and pulp. |
Bushfire resistance: measured by bushfire attack level (BAL) | BAL 12.5 and 19 - all AS3959 required applications |
Least attractive features | Poor drought tolerance. Thin bark makes this species fire-sensitive, sensitive to sunburn and easily ringbarked. |
Most attractive features | Fast growth, drought fodder, legume (nitrogen fixing), compatible with fast-growing eucalypts. Excellent timber to work. |
Status as a plantation species in Gippsland | Minor. Most often used as a nurse crop species. Has potential on high-rainfall clay loam sites. |
Note: Timber characteristics and durability are based on Australian Standard: Timber Natural durability ratings (AS 5604–2005). Refer to the Appendix for an explanatory table. Where (?) applied, rating is based on field experience.
Note: Bushfire resistance measurement is based on naturally bushfire resisting timbers, which are those with inherent bushfire-resisting properties. For more information refer to Australian Standard 3959:2018.
Assumptions and notes
- Sites considered for planting contain at least one metre of soil above an impeding layer (e.g., bedrock or layer impenetrable to roots).
- Please note that most (if not all) eucalypts in Gippsland grow best on sheltered sites.
- Overall slow drying time across air and kiln-dried schedules is recommended to minimise drying degrade. This is the best starting point for inexperienced operators.
References
Beadle CL and Brown AG (eds) 2007. Acacia utilisation and management: adding value. RIRDC Publication No. 07/095, Rural Industries Research and Development Corporation, Canberra.
Boland DJ et. al (1992). Forest trees of Australia. CSIRO Australia.
Bootle KR (1983). Wood in Australia – Types, properties and uses. McGraw Hill, Australia
Carnegie AJ (2002). Field guide to common pests and diseases in eucalypt plantations in NSW. Research and Development Division of State Forests, NSW.
Clarke B, McLeod I and Vercoe T (eds) 2009. Trees for farm forestry: 22 promising species. RIRDC Publication No. 09/015. Rural Industries Research and Development Corporation, Canberra.
Mortimer J (2003). A selection of alternative timbers. Taitua Books, NZ.
National Association of Forest Industries (2004). Timber species and properties, revised edition. Timber Manual Datafile P1
Nicholas ID, Gifford HH and Kimberely MO (1997). Siting black walnut. FRI Bulletin no. 188
Phillips C (1996). Insects, diseases and deficiencies associated with eucalypts in South Australia. Primary Industries SA Forests.
Poole B, Waugh G and Yang JL (2017). Potential for growing and processing durable eucalypts in New Zealand. Publication No. SWP-T036. Solid Wood Innovation. Specialty Wood Products Research Partnership.
Reid R (2017). Heartwood. The art and science of growing trees for conservation and profit. Melbourne Books.
Tepper CJ (2002). Plantation eucalypt species for solid wood products – a profile of Eucalyptus muelleriana. Gottstein Fellowship Report for the Gottstein Memorial Trust
Tepper CJ (2008). Site Matching and Establishing Eucalypt Sawlog Species in Southern Australia. In Beadle CL and Brown AG (eds) 2008. Plantation eucalypts for high value timber. RIRDC Publication No. 08/113, Rural Industries Research and Development Corporation, Canberra.