Southern mahogany
Southern mahogany (Eucalyptus botryoides) is a fast-growing Eucalyptus preferring 1000 mm or more of rainfall annually and fertile clay loam/sand soils. A durable species that can establish quickly, dominating sites early.
Table 1: General characteristics for southern mahogany
Characteristic | Description |
|---|---|
Botanical name | Eucalyptus botryoides |
Growth rate in preferred conditions | Fast |
Estimated rotation length (yr) in preferred conditions to produce 60 cm diameter at breast height | 25+ |
Preferred annual rainfall (mm/yr) | 1000+ |
Minimum rainfall (mm/yr) | 800 |
Preferred elevation (m) ASL | 0–150 |
Preferred landscape position | Protected aspects. Lower slopes and flats. Keep away from exposed locations. |
Preferred Soil | Fertile clay loam/sand |
Prohibitive soil | Heavy clays. Duplex soils. |
Poor drainage tolerance | Low to moderate |
Dry site tolerance | Low |
Frost tolerance | Moderate |
Pest and disease problems: trees planted on unsuitable sites are more prone to insect and disease issues | Prone to insect damage in dry conditions (e.g. lerp psyllids, leaf blister sawfly, Christmas beetles, cerambycid/longicorn beetles, cossid moths). |
Table 2: Timber characteristics for southern mahogany
Characteristic | Description |
|---|---|
Strength: seasoned timber only | SD3: moderately high |
Durability: in ground | above ground | 3 | 2 |
Drying: green to 12% moisture content | Slow in drying. Susceptible to end splitting. Reconditioning needed to overcome collapse. Shrinkage about 5% radial and 10% tangential. |
Main commercial products | Interior joinery, panelling, veneers, posts and poles, sleepers, light and heavy construction, flooring, firewood |
Bushfire resistance: measured by bushfire attack level (BAL) | BAL 12.5 and 19 – all AS3959 required applications |
Least attractive features | Heavily branched and therefore susceptible to wind damage. Does not handle exposure. Very susceptible to insect attack. Late development of heartwood and high shrinkage in drying. |
Most attractive features | Can establish quickly, dominating sites early. Attractive red/pink timber. Sapwood resistant to lyctid borer. |
Status as a plantation species | Is being grown in plantations mainly in Gippsland on protected 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
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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
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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.