Common Name: Grey Gum

General Information

Eucalyptus propinqua is an evergreen tree with an open, moderately small crown; it can grow 35 - 40 metres tall. The straight bole can be free of branches for 50 - 65% of the total tree height and up to 110cm in diameter[, , ].
The tree yields an important construction timber in Australia and so is commonly harvested from the wild. It has given good results after planting in Rwanda and Zimbabwe[].

Known Hazards

None known

Botanical References

,

Range

Australia - northern New South Wales, southern Queensland.

Habitat

Locally frequent, in wet coastal forest on soils of low to medium fertility; at elevations up to 350 metres[, ].

Properties

Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	35.00 m
Pollinators	Bees, Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Eucalyptus propinqua is native to the warm temperate and subtropical climate of eastern Australia, where it is found at elevations up to 350 metres. Rainfall occurs mainly in the summer, with a mean annual rainfall within the range 875 - 1,400mm and a dry season that is not severe of up to 4 months. The mean maximum temperature of the hottest month is 27 - 33°c; mean minimum temperature of the coldest month is 4 - 10°c, and there are generally around 1 - 10 frosts a year[]. When dormant, the plant can survive temperatures down to about -3°c, but young growth is more tender and can be severely damaged at 0°c[].
Requires a sunny position, succeeding in a range of well-drained soils of moderate fertility[]. Prefers a pH in the range 6 - 7, tolerating 5.5 - 7.5[].
The plant develops a lignotuber - this is a woody tuber that starts to develop near the base of seedlings and can become massive in the mature plants of some species. It possesses embedded vegetative buds, allowing the plant to regenerate following crown destruction, for example by fire[].
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[].
Eucalyptus species have not adopted a deciduous habit and continue to grow until it is too cold for them to do so. This makes them more susceptible to damage from sudden cold snaps. If temperature fluctuations are more gradual, as in a woodland for example, the plants have the opportunity to stop growing and become dormant, thus making them more cold resistant. A deep mulch around the roots to prevent the soil from freezing also helps the trees to survive cold conditions[]. Many members of this genus are remarkably adaptable however, and there can be a dramatic increase in the hardiness of subsequent generations from the seed of survivors growing in temperate zones[].

Edible Uses

None known

Medicinal

In traditional medicine in DR Congo Eucalyptus propinqua is one of a range of Eucalyptus species that are recorded to be used for treatment of respiratory problems, fever and skin diseases[].

Agroforestry Uses:

The flowers are a good source of nectar and pollen for bees[].

Other Uses

The fresh leaves contain 1 - 1.8% essential oil. The main components are alpha-pinene, 1,8-cineole, and monoterpene
alcohols[].

The heartwood is red to red-brown, the sapwood is pale red. The texture is coarse but uniform, the grain is interlocked. The wood is very heavy, hard, tough, stiff, very strong and very durable, though brittle. It is resistant to termites and is also fire-resistant. It is suitable for construction, flooring, interior trim, boat building, vehicle bodies, agricultural implements, mine props, railway sleepers, poles and piles[, , , , , ].
The wood is used for fuel[].

Propagation

Seed - surface sow late winter/early spring in a sunny position in a greenhouse[, , ]. Species that come from high altitudes appreciate 6 - 8 weeks cold stratification at 2°c[]. 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. Plant out into their permanent positions in early summer and give them some protection from the cold in their first winter. The seed can also be sown in early summer, the young trees being planted in their final positions in late spring of the following year. The seed has a long viability[].