Common Name: Flooded Gum

General Information

Eucalyptus grandis is an evergreen tree with a wide-spreading, rather thin crown; usually growing 40 - 55 metres tall but exceptionally to 75 metres[, ]. The bole is usually straight and cylindrical, unbranched for up to 50 - 75% of its height and 120 - 300cm in diameter[, ].
Flooded gum is one of the most important commercial eucalypts, with more than half a million hectares planted for wood in tropical and subtropical areas on four continents[]. The tree is also commonly grown as an ornamental in parks and larger gardens[].

Known Hazards

None known

Botanical References

Range

Australia - northern New South Wales, Queensland.

Habitat

Tall, open forest in sheltered valleys and on hill slopes, often in pure or almost pure stands, sometimes in mixed forests. In the south of its range, it is found on flats and lower slopes of deep, fertile valleys and at the edge of rainforests[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	50.00 m
Growth Rate	Fast
Pollinators	Bees, Insects
Self-fertile	Yes
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Eucalyptus grandis is a plant of the humid subtropical and tropical regions of eastern Australia, it grows in areas with mean minimum temperatures during the coldest month ranging from 2 - 10°c and mean maximums near 29°c during the hottest month[]. Rainfall averages 1,020 - 1,780mm, concentrated in the summer but with monthly precipitation during the dry season of at least 20mm[]. Plants can experience occasional frosts in the high parts of its range[]. So long as the temperature drops gradually over a period of days, the tree can tolerate frost of -3°c, but rapid falls to that temperature can cause severe damage[]. When dormant, the plant can survive temperatures down to about -8°c, but young growth is more tender and can be severely damaged at -1°c[].
Requires a sunny position and a deep, free-draining soil, growing best on fertile loam or clay-loam soils, but it will also perform well on lighter sandy soils, provided these are deep enough[, ]. Prefers a pH in the range 5.5 - 6.5, tolerating 5 - 7.5[].
Whilst most Eucalyptus species, grown in small numbers outside their native range, can be an attractive and useful addition to the landscape, certain species (including this one) are more problematic. When grown in monocultures, especially outside their native range, they can become an environmental disaster. They are voracious, especially in their use of water; they are allelopathic, inhibiting the growth of the native flora; they reduce habitats for native fauna; and encourage the worst possible attitudes to land use and conservation[].
A very fast-growing tree, height increase in young trees of 2 metres per year are common, with some trees averaging 4 metres for the first 10 years or more[, ].
Trees respond well to coppicing[].
When grown for pulpwood, fuel wood and timber for mining, a 6 - 10 year rotation is common. In most countries, no thinning is done on these short rotations[].
For saw logs, a rotation of 30 years is recommended with thinning at ages 7, 11 and 15 years, leaving a final stocking of 250 stems/ha[].
The use of boron to reduce die-back and improve the growth rate is essential[].
For most types of products, one seedling rotation, followed by at least two coppice rotations, is common practice[].
Trees normally produce a strong taproot, with few laterals[].
Trees can commence flowering when 4 - 5 years old[]. Under natural conditions, the tree bears heavy seed crops every 2 - 3 years[]. A fully mature tree can produce 2 kg of seed annually[].
This species often hybridizes with the closely related Eucalyptus saligna, from which it is distinguished most easily by the shape ofthe fruit valves[].

Edible Uses

None known

Medicinal

A decoction of ground branch tips is taken against constipation[].

Euglobals from the leaves have shown anti-carcinogenic activityand inhibitory effects on Epstein Barr virus activation[].

Agroforestry Uses:

The tree is planted in windbreaks[].
Soya beans (Glycine max), interplanted with this tree as part of an agroforestry research project in southeastern Brazil, suppressed weeds without adversely affecting tree survival and growth[]. Maize and sorghum have also been found compatible to grow with this plant[].
When planted adjacent to avocado orchards, it reduces the yields by shading and competing unfavourably with the avocados for light, nutrients and water[].
The flowers are a good source of nectar and pollen for bees[, ].

Other Uses

The leaves yield 0.3 - 4.7% essential oil, containing alpha-pinene (30.4 - 68.9%), beta-pinene (0.4 - 6.6%), p-cymene (up to 16.1%), terpinen-4-ol (up to 10.7%), 1,8-cineole (up to 4.8%), alpha-terpineol (0..5 - 8.0%), limonene (2.4 - 5.6%) and (E)-beta-ocimene (up to 9.4%). The essential oil has shown larvicidal activity against the mosquito Aedes aegypti, with alpha-pinene being the principal larvicidal component[].

The colour of the heartwood ranges from almost white to pink or dark red; it is clearly demarcated from the 2 - 5cm wide band of paler sapwood. The grain is straight or interlocked; the texture medium to coarse; gum veins are common. The wood is moderately strong, moderately heavy and soft, being softer and lighter than that of many other eucalypts. It is moderately durable at best, being resistant to dry wood borers, somewhat resistant to fungi and susceptible to termites - untreated wood is not suitable for use in contact with the ground. The sapwood is generally resistant to Lyctus borers. It is somewhat difficult to dry, but checking can be avoided by careful control of the conditions during the early stages of drying. The wood is usually not very stable in service. The wood works well with machine and hand tools, but the surface may be woolly and the wood has a tendency to splinter. It saws cleanly, planes excellently and takes all kinds of finish well. Nail and screw holding properties are good, but the wood tends to split on nailing unless pre-bored. The gluing properties are good. The wood has been used for fence posts, building, transmission and telephone poles, boxes and hooks. It is especially used for boat building, flooring, plywood, panelling and general construction. It can also be used for sawn timber but has tendency to split[, , , , ]. It has been used as a source of pulp for making paper[].
Large quantities of the wood are used for charcoal, for iron smelting, for example in Brazil. The firewood is used for domestic purposes and for curing tobacco[]. The wood has an energy value of 18,100 - 19,400 kJ/kg[].

Propagation

Seed - surface sow in a sunny position and make sure the compost is not allowed to dry out[, , ]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[]. Germination takes 7 - 14 days[]. Pot up the seedlings into individual pots as soon as the second set of seed leaves has developed, if left longer than this they might not move well. The seedlings are ready for planting in the field when they are 25 - 30 cm tall, usually after 3 - 5 months.
The seed has a long viability[].
Cuttings from tiny seedlings root readily, but rooting capability ceases before seedlings are 1 metre tall because of natural rooting inhibitors produced by adult leaves[]. However, even in adult trees, cuttings from epicormic shoots, induced at the base of the tree by felling or girdling, retain the ability to root[].
Coppice shoots from stumps have also been used for propagation[].

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