Black wattle
Black wattle (Acacia mearnsii) is a very fast-growing acacia species preferring high annual rainfall and clay loam soils. It is most often used as a nurse crop species. It has great potential as a fast-growing firewood option.
Table 1: General characteristics for black wattle
Characteristic | Description |
|---|---|
Botanical name | Acacia mearnsii |
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) | 1000+ |
Minimum rainfall (mm/yr) | 800 |
Preferred elevation (m) asl | 0–850 |
Preferred landscape position | Lower slope |
Preferred soil | Clay loam |
Prohibitive soil | Duplex and/or heavy clay |
Poor drainage tolerance | Moderate to high |
Dry site tolerance | Moderate |
Frost tolerance | Very high |
Pest and disease problems: | Fireblight larvae, Longicorn borers |
Table 2: Timber characteristics for black wattle
Characteristic | Description |
|---|---|
Strength: seasoned timber only | SD4: moderate |
Durability: in ground | above ground | 4 | 4 |
Drying: green to 12% moisture content | Shrinkage at about 4% radial and 6% tangential |
Main commercial products | Internal flooring, tanning bark, furniture, firewood |
Bushfire resistance: measured by bushfire atltack Level (BAL) | Not available. Given slightly higher wood density than silver wattle, it is expected to have a similar BAL. |
Least attractive features | Tendency to branch vigorously. Fire sensitive. Requires intensive silviculture to prevent suppression of slower growing species. |
Most attractive features | Fast growth, legume, tolerates poor drainage and good option for mixed species stands. Strong firewood potential. |
Status as a plantation species | Minor. Most often used as a nurse crop species. Has great potential as a fast-growing firewood option. |
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.