Closely related to Casuarina cunninghamiana and often hybridises in the wild with that species[].

Common Name: Swamp Oak

General Information

Casuarina glauca is a moderately fast-growing, evergreen tree that can reach a height of around 18 metres with a bole up to 60cm in diameter. The plant often suckers freely to form colonies[, ].
An excellent agroforestry tree, it is valued for its wood and its ability to stabilize and reclaim soil. The tree has been widely planted outside of its native country and has proved to be superior to many other species under Mediterranean type climates and in many difficult sites[, ]. However, it should be used with some care since it has the potential to become weedy[].

Known Hazards

There is a report that the pollen might be allergenic[].

Botanical References

, ,

Range

Australia - New South Wales, Queensland, Victoria

Habitat

Usually found in swampy localities[]. Near salt water estuaries, along sluggish creeks and occasionally on rising ground[]. Often forming pure stands as an open forest or woodland[].

Properties

Weed Potential	Yes
Edibility Rating
Other Uses Rating
Habit	Evergreen Tree
Height	18.00 m
Growth Rate	Fast
Pollinators	Wind
Cultivation Status	Cultivated, Wild

Cultivation Details

Casuarina glauca grows best at elevations lower than 900 metres[]. It is reported to tolerate an annual precipitation in the range of 500 to 4,000mm, estimated annual temperature range of 18 to 28°c, and a pH of 5 to 8[]. Plants have grown in Israel under a soil crust of salt (50,000 ppm)[]. The plant rarely tolerates temperatures lower than -3°c[]. Coastal plants do not experience frost, but inland there can be 1 - 5 frosts per year[].
Requires a well-drained moisture-retentive soil in full sun[]. Succeeds in most soils in Australian gardens, including saline ones, and is tolerant of salt spray[, , ]. Plants are reported to tolerate high pH, limestone soils, low pH, salt and sand dunes, sea spray, periodic water-logging, drought, weeds, and wind[, ]. In fine-textured clays, even in waterlogged soils, it can develop a deep root system[].
Plants coppice and produce root suckers vigorously[]. Spreading by means of root suckers, this species has become a pest in some parts of Florida[].
Closely related to Casuarina cunninghamiana, though somewhat less hardy[], it often hybridises in the wild with that species[].
In fine-textured clays, even in waterlogged soils, this species can develop a deep root system, whilst Casuarina cunninghamiana and Casuarina equisetifolia develop shallow roots and grow poorly[].
A dioecious species, both male and female plants need to be grown if seed is required[]. The male flowers are produced on terminal spikes, the females in cone-like structures[].
This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[]. Although Nitrogen nodulation is most successful at Ph 6 to 8, some natural stands are well nodulated in acid soils (Ph 4)[]. Inoculation of seedlings with pure culture of effective strains of Frankia rhizobia is recommended when introducing the species to new areas[].

Edible Uses

The needles are chewed to relieve thirst[]. We assume that this means the leaves[].

Medicinal

None known

Agroforestry Uses:

The plant suckers freely and forms a good windbreak[]. It has a rapid colonizing ability on disturbed soils, especially in coastal or salt affected situations[]. The low branching habit and extensive litter production help reduce soil erosion[]. It has been used to reclaim land, especially eroded mountainsides, to stabilize dunes and streambanks, and to provide shelterbelts[, ]. The plant can spread very freely by means of suckers and has become a noxious weed in some areas - its planting is banned in some parts of Florida[]. Ditches are sometimes dug on either side of the shelterbelt planting in order to control its spread[].

Other Uses

The heartwood is brownish with conspicuous rays, the narrow band of sapwood is paler coloured. The wood is very dense, hard, strong, tough and fissile. The sapwood is resistant to Lyctus borer. A nicely marked, attractive timber, it is used for turnery, tool handles, rafters, flooring, fencing rails, shingles, and salt-water pilings[, , , ]. It is said to be better than hickory (Carya spp) for making tool handles[].
The average fibre length for young trees is 0.97 mm; the fibre is used to make a particleboard of adequate strength and stability[].
An excellent fuel, the wood has a calorific value of 4,700 kcal/kg, it splits easily, and burns slowly with little smoke or ash. It can also be burned when green, an important advantage in fuel-short areas[, ]. It produces an excellent charcoal[]. After 4 years, trees begin to shed about 4 tonnes of cones/year. These, too, make good pellet-sized fuel[, ].

Propagation

Seed - the optimum temperature for germination is 30°c[]. Sow late winter to early summer in a greenhouse and only just cover the seed[]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in a greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. There are 440,000 - 550,000 seeds per kilo[].
Cuttings of half-ripe wood, mid summer in a frame[, ]. Treatment of terminal branchlets, heel cuttings or basal sprouts especially from juvenile plants with root-inducing hormone powder has proved successful[]. Cuttings should be maintained on a mist bench with bottom heat[].
Vegetative propagation by air layering has been attempted with limited success[].