Prota 7(1): Timbers/Bois d’œuvre 1
Fragm. 11: 44 (1878).
2n = 22
Gympie messmate, cloeziana gum (En).
Origin and geographic distribution
Eucalyptus cloeziana is native to Queensland (Australia). It is among the more important plantation species in Zimbabwe, where it is used for poles and pulping. Plantations have been established in Zambia to supply timber for industrial use. Eucalyptus cloeziana has also been planted in Nigeria, Congo, DR Congo, Kenya, Uganda, Malawi, Mozambique, Madagascar and South Africa.
Eucalyptus cloeziana produces very good poles, having few equals as telephone or transmission poles, due to their form, strength and durability. The wood is also used for construction, cladding, railway sleepers, bridge planking, piers, posts and mine props, and is suitable for flooring, joinery, ship building, vehicle bodies, handles, ladders, sporting goods, agricultural implements and turnery. It is used as fuelwood and it can be made into charcoal of good quality. The flowers provide bee forage.
The heartwood is yellow-brown; the up to 2.5 cm wide sapwood is paler. The grain is straight, texture fairly fine and uniform. The wood is heavy, with a density of 820–1000 kg/m³ at 12% moisture content. It dries fairly slowly, with a tendency to checking and warping, but with careful handling good results can be obtained. The rates of shrinkage from green to 12% moisture content are 2.0–6.6% radial and 4.6–12.5% tangential. The wood is strong and very tough. At 12% moisture content, the modulus of rupture is 106–175 N/mm², modulus of elasticity 11,800–18,100 N/mm² and compression parallel to grain 73–85 N/mm².
The wood saws and works remarkably well, which is probably due to the straight grain, but it splits readily. It holds nails and screws well, but pre-boring is necessary. It planes to an attractive finish and polishes well. The wood is very durable and highly resistant to termites. The sapwood is not susceptible to Lyctus borers. The heartwood is extremely resistant to impregnation with preservatives.
The leaves yield up to 1.9% essential oil, of which 2 forms have been distinguished: the pinene-rich form (containing 16–78% α-pinene) and the tasmanone-rich form (up to 96% tasmanone).
Evergreen, large tree up to 55 m tall; bole long, up to 150(–300) cm in diameter; bark surface brown, grey or grey-yellow, longitudinally fissured or with thick irregular scales; branchlets smooth. Leaves alternate, simple and entire; stipules absent; petiole 1–1.5 cm long, flattened; blade lanceolate, 8–13 cm × 1–3 cm, acuminate at apex, discolorous, pinnately veined. Inflorescence an axillary umbel-like dichasium, 4–7-flowered, often several together in a large panicle; peduncle rounded or angular, 5–10 mm long. Flowers bisexual, regular; pedicel 1–4 mm long; flower buds club-shaped to globular ovoid, divided into a hemispherical hypanthium (lower part) 2–4 mm × 3–4 mm and a hemispherical or conical operculum (upper part) 2–3 mm × 3–4 mm and shed at anthesis; stamens numerous; ovary inferior, 3–4-celled. Fruit a hemispherical or globular capsule enclosed in a woody hypanthium, 5–10 mm × 6–12 mm, opening with 3–4 level or exserted valves, many-seeded. Seeds cube-shaped or elongated, yellow-brown.
In the savanna zone of Nigeria a mean annual height growth of 1.8 m was achieved over the first 5 years after planting, with the tallest trees being 12.2–15.2 m high and 12–15 cm in bole diameter. In the southern savanna zone of Nigeria the annual height growth in the first 2 years was 2.1–2.4 m, and in the northern savanna zone the tallest 4.5-year-old trees were 14.6 m high with a bole diameter of 16.8 cm. In experiments with Eucalyptus cloeziana in Congo the average height of different provenances was 11.1–20.7 m after 5.5 years.
Eucalyptus comprises about 800 species, endemic to Australia, except for about 10 species in the eastern part of South-East Asia. The genus is divided into several subgenera (7–10, depending on the author), which are subdivided into many sections and series. The results of phylogenetic studies within Eucalyptus suggest that the genus is polyphyletic, hence not of a single evolutionary origin, and consequently it has been proposed to divide the genus into several distinct genera. This has not yet been done, mainly because of the nomenclatural whirlpool this would bring about. Eucalyptus species hybridize easily, which adds to the taxonomic complexity.
Many Eucalyptus species are cultivated outside their natural distribution area, in tropical, subtropical and temperate regions, because of their rapid growth and adaptation to a wide range of ecological conditions. In Africa Eucalyptus globulus Labill. has long been the most important Eucalyptus species, but its importance has declined, although it is still important in cooler climates. Nowadays the main commercial species in Africa are Eucalyptus grandis W.Hill ex Maiden in more fertile locations, Eucalyptus camaldulensis Dehnh. in drier regions, and Eucalyptus robusta Sm. in more tropical regions. Many other Eucalyptus species have been introduced into tropical Africa, of which the actual distribution and importance in tropical Africa are not exactly known, but which are surely less important. Less important Eucalyptus species that are planted in tropical Africa and that are not obviously less used for timber than for other purposes, such as fuelwood, pulping, erosion control or ornamental purposes, include the following:
Eucalyptus bosistoana F.Muell. (‘coast grey box’) is a medium-sized to fairly large tree up to 40(–60) m tall and up to 100(–200) cm in diameter, native to New South Wales and Victoria in Australia. It has been planted in Ethiopia, Kenya, Uganda, Zimbabwe and South Africa. The wood is used for heavy construction, piles, poles and railway sleepers. It is very heavy, with a density of 900–1200 kg/m³ at 12% moisture content, strong, hard and very durable.
Eucalyptus gummifera (Sol. ex Gaertn.) Hochr. (‘gummifera gum’, ‘bloodwood’) is a medium-sized tree up to 35 m tall, with bole up to 120 cm in diameter, native to coastal eastern Australia. It grows well in Madagascar, especially at low altitudes near the coast, and it has been planted in Kenya and Tanzania. The wood is strong and very durable, but frequent gum pockets and rings are a defect, resulting in the wood being used mainly for poles, piles, posts, railway sleepers, mining constructions and hardboard production. It is also used as fuelwood and for charcoal making. The wood has a density of 730–880 kg/m³ at 12% moisture content.
Eucalyptus microcorys F.Muell. (‘tallowwood’, ‘microcorys gum’) is a large tree up to 60 m tall, with bole up to 210 cm in diameter, native to eastern Australia. It has been planted in DR Congo, Rwanda, Ethiopia, Kenya, Uganda, Tanzania, Malawi, Zambia, Angola, Zimbabwe, Madagascar and South Africa. The wood is particularly valued for flooring (parquetry, dance floors), but also for construction, furniture, railway sleepers, poles, posts, vehicles, and wheelwork. It is also used as fuelwood. The wood is heavy, with a density of 730–1010 kg/m³ at 12% moisture content, strong, tough and hard. Eucalyptus microcorys is also used in windbreaks and as a shade tree, and the flowers provide bee forage.
Eucalyptus muelleriana A.W.Howitt (‘yellow stringybark’, ‘muelleriana gum’) is a medium-sized to fairly large tree up to 40(–55) m tall and up to 120 cm in diameter, native to south-eastern Australia. It has been planted in Kenya, Tanzania, Madagascar and South Africa. The wood is used for construction, poles, piles, posts and railway sleepers. At 12% moisture content, the density of the wood is 740–900 kg/m³.
Eucalyptus obliqua L’Hér. (‘messmate’, ‘messmate stringybark’, ‘Tasmanian oak’) is a very large tree up to 70(–90) m tall, with bole up to 210(–300) cm in diameter, native to south-eastern Australia. It has been planted in Nigeria, Ethiopia, Kenya, Tanzania, Zambia, Zimbabwe, Madagascar and South Africa. It is one of the most important hardwood species in Australia. The wood is used for construction, interior trim, furniture, boxes, poles, piles, posts, railway sleepers, veneer, plywood and woodwool. It is also used as fuelwood, for charcoal making and for pulping. The density of the wood is 700–785 kg/m³ at 12% moisture content.
Eucalyptus pilularis Sm. (‘blackbutt’, ‘pilularis gum’) is a very large tree up to 70 m tall, with bole up to 250 cm in diameter, native to eastern Australia. It has been planted in Nigeria, DR Congo, Kenya, Tanzania, Malawi, Zambia, Zimbabwe, Madagascar and South Africa, but nowhere on a large scale. It is one of the main hardwoods of Australia, used for construction, flooring, panelling, poles, posts, railway sleepers and veneer. The wood is moderately heavy, with a density of 740–960 kg/m³ at 12% moisture content, and strong, tough and moderately hard. It makes good charcoal.
Eucalyptus propinqua H.Deane & Maiden (‘propinqua gum’, ‘grey gum’) is a medium-sized to fairly large tree up to 40 m tall, with bole up to 110 cm in diameter. It is native to coastal eastern Australia, and has given good results after planting in Rwanda and Zimbabwe. It yields an important construction timber in Australia, and the wood is also suitable for flooring, interior trim, boat building, vehicle bodies, agricultural implements, mine props, railway sleepers, poles and piles. It is also used as fuelwood. The wood is very heavy, with a density of 1020–1060 kg/m³ at 12% moisture content. It is hard, tough, stiff and very strong. 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.
Eucalyptus resinifera Sm. (‘red mahogany’, ‘resinifera gum’) is a fairly large tree up to 45 m tall, with bole up to 150 cm in diameter. It is native to coastal eastern Australia, and it has been planted in DR Congo, Eritrea, Ethiopia, Uganda, Kenya, Tanzania, Zambia, Zimbabwe, Madagascar and South Africa. The wood is considered one of the best Australian hardwoods. It is used for construction, boat building and railway sleepers, and also used as fuelwood and for charcoal making. The wood has a density of 580–890(–1070) kg/m³ at 12% moisture content. It is stiff, strong, tough and hard.
Eucalyptus sideroxylon Woolls (‘red ironbark’, ‘ironbark’) is a medium-sized tree up to 35 m tall, with bole up to 120 cm in diameter, native to eastern Australia. It has been planted in DR Congo, Ethiopia, Kenya, Uganda, Tanzania, Zambia, Zimbabwe, Madagascar and South Africa. The wood is used for construction, railway sleepers and posts. It is also used as fuelwood and for making charcoal. The wood is very heavy, with a density of 1040–1105 kg/m³ at 12% moisture content. It is strong, stiff and hard. The leaf oil has been produced commercially in South Africa, where it was used as a flotation agent in the mining industry. Eucalyptus sideroxylon is also planted as a shade and ornamental tree, and the flowers provide bee forage.
Eucalyptus cloeziana is grown up to 2350 m altitude, in areas with a mean annual temperature of 16–27°C, a mean maximum temperature of the warmest month of 27–36°C, a mean minimum temperature of the coldest month of 6–17°C and an average annual rainfall of 700–2000 mm, with a dry season of up to 5 months. The tree is suitable for humid highland conditions, but it is sensitive to frost. It prefers well-drained, neutral to acidic, medium-textured soils.
Eucalyptus cloeziana is propagated by seed. Recorded 1000-seed weights range from 2.5–7(–30) g. The seed can be stored for several years under dry, cold and airtight conditions. Pre-treatment before sowing is not needed, but the germination rate is often poor. Seedlings are planted out in the field when they are 4–5 months old. Eucalyptus cloeziana coppices well. When grown for poles, coppice rotations of 6–12 years are employed. Eucalyptus cloeziana is resistant to the eucalyptus snout beetle (Gonipterus scutellatus), an important pest of many other Eucalyptus spp. Seedlings in the nursery are susceptible to damping off, and they may suffer from termite attacks. Annual volume increments are 15–34(–41) m³/ha. In an experiment in Zambia mean annual increments after 12 years were 26.5 m³/ha for a density of 2500 trees/ha, 25.6 m³/ha for 1250 trees/ha, 19.5 m³/ha for 833 trees/ha, 16.0 m³/ha for 357 trees/ha, 10.1 m³/ha for 250 trees/ha and 8.7 m³/ha for 156 trees/ha.
Genetic resources and breeding
Eucalyptus cloeziana shows a large genetic variability, indicating potential for selection of provenances with favourable characteristics.
Eucalyptus cloeziana combines favourable wood properties with good growth characteristics, abundant coppice regeneration and an attractive appearance. In tropical Africa it is especially recommended for regions with an average annual rainfall of 1000–1500 mm and a dry season of 4–5 months.
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Correct citation of this article:
Brink, M., 2008. Eucalyptus cloeziana F.Muell. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.
obtained from Carlton McLendon, Inc.
transverse surface of wood