Eucalyptus robusta

Why is this Species Important?

• It provides a reliable winter flowering food source for native animals and threatened species such as the Squirrel Glider, Grey-headed Flying Fox, migratory birds such as Regent Honeyeater and Swift Parrot and many other bird and mammal species.
• It provides a tall canopy cover over shrub and groundcover species which combine to form a diverse flora community. Trees assist in stabilising soils in drainage areas where erosion could be a problem.
• Swamp Mahogany is not listed as a threatened species under the Threatened Species Conservation (TSC) Act, 1995 however, it is identified as being a regionally significant foraging species and occurs in several endangered ecological communities, including:
• Swamp Sclerophyll Forest on Coastal Floodplains, and
• River Flat Forest in Coastal Floodplains.

There is a high probability that if Swamp Mahogany trees are present within a vegetation community, that the community may be an endangered ecological community.

Description 

• Swamp Mahogany is a medium to tall eucalypt with large leathery leaves; and distinctive fruit capsules.¹
• The bark of Swamp Mahogany is soft and spongy to touch. The bark is continuous to the ends of branches, deeply furrowed and dark red-brown in colour.² In dry conditions the bark may be grey.
• Swamp Mahoganies have large bunches of cream flowers that occur regularly during the winter months.³

What other Species look like Swamp Mahogany?

• Bangalay (Eucalyptus botryoides); mostly found within 2km of the ocean, often near old sand dunes or in depressions between dunes.
• Red Mahogany (Eucalyptus resinifera), mostly found in tall moist forest (not swamps), has smaller, less leathery leaves and thick, rough, furrowed bark held in firm elongated slabs or plates.
• Hybrid species with characteristics of several species may also develop.

Where does Swamp Mahogany occur?

• Swamp Mahogany occurs in freshwater swamps, floodplains and poorly drained creeklines.^1&2
• Swamp Mahogany is usually the dominant eucalypt species growing in swamp forests and open forests along coastal lagoon edges or coastal creeks.

Some Places that Swamp Mahogany can be Found

Gosford:

• Lisarow Wetland; Kincumber Village Reserve, Carrack Road, Kincumber; and Cockle Bay Nature Reserve, Empire Bay.

Wyong:

• Wyrrabalong National Park - the Western end of Lilly Pilly Loop trail; Berkeley Creek; Glenning Valley.

Lake Macquarie:

• Along the edges of Lake Macquarie with large areas near the Myuna Bay recreation centre; North side of Soldiers Road, Pelican.

Threats to Survival 

• Alteration to natural hydrological regimes.
• Vegetation clearing and removal.
• Exposure to acid sulphate soils causing death by sulfuric acid uptake.
• Poisoning by humans.

Management Issues

• Plant Swamp Mahoganies in suitable locations.
• Weed understorey to enhance seed regeneration.
• Avoid soil compaction surrounding the root system.
• Reduce bushfire risk where possible.
• Build elevated bushwalking tracks to avoid soil compaction.
• Maintain surrounding canopy cover and soil cover to avoid evaporation by planting dense understorey species such as ferns and paperbarks.

Local Policies Protecting Swamp Mahogany

• Listed as a species in the Gosford Significant Tree register particularly in;
• Koolewong, East Gosford, Matcham, Umina Beach & Wyoming.
• Listed in Wyong Development Control Plan 14 - Tree management as;
• Protected native plant contained in Schedule 3 of the National Parks & Wildlife Act 1974.
• Keystone Species.
• Species of Local Conservation Significance.
• Tree of Cultural Significance.
• Listed in Lake Macquarie Tree preservation Guidelines as a:
• Regionally significant species

Useful Web Links

• Department of Environment and Climate Change - www.dec.nsw.gov.au

Further Reading

• Keith, D. (2004) Ocean Shores to Desert Dunes: The Native Vegetation of New South Wales and ACT. Dept of Environment and Conservation (NSW).

Bibliography

1. Brooker, I. and Kleinig, D. (1996) Eucalyptus: An illustrated Guide to Identification. Reed Books. ISBN 0 73010494 X.
2. Brooker, M.I.H. and Kleinig, D.A. (1999) Field Guide to Eucalypts: Vol. 1 South-eastern Australia. (2^nd ed.). ISBN1876473 03 7.
3. Cronin. L (1988) Key Guide to Australian Trees. Reed Books. ISBN 0 7301 0252 1.