Eucalyptus

Eucalyptus trees becoming popular transplants around the globe

By Jo-Ann Kaiser

When it comes to eucalyptus trees, one naturally thinks of Australia, where the trees dominate the forests in sheer numbers and in size. There are more than 500 kinds of “eucalypts” in Australia. The fast growing and impressive eucalyptus trees routinely grow to 180 feet but can grow to 300 feet or more, making this species one of the tallest trees in the world.

The commercially prominent eucalypts include bluegum (Eucalyptus globulus), jarrah (Eucalyptus marginata), karri (Eucalyptus diversicolor), delgupta (Eucalyptus delgupta) and eucalyptus (Eucalyptus grandis).

Trees from Eucalyptus globulus are commonly found in Tasmania but also cultivated in plantation settings in subtropical climates, including California and Hawaii in the United States, and in Spain, South America and East Africa. Material from Chile is sometimes called Chilean oak.

Family Name

Eucalyptus globulus and related species of the Family Myrtaceae

Common Names

Blue gum eucalyptus, bluegum, Chilean oak, Tasmanian blue gum.

Height/Weight

Average height is 150 to 180 feet with trunk diameters of 3 to 5 feet. Specific gravity for the wood is 0.80 for forest-grown material, 0.67 for plantation-grown; average weight is 61 pounds per cubic foot for forest-grown, 51 pounds per cubic foot for plantation material.

Properties

  • Slightly difficult to season with some checking and tendency to warp and collapse.
  • Material saws well and generally works well.
  • Medium texture.

Looks

Bluegum’s heartwood is a pale yellow-brown; the sapwood is gray-white. Its grain is usually interlocked. Figures include plain eucalyptus and figures such as pommele. Uses for bluegum eucalyptus include pallets, fenceposts, general construction, veneer, veneer panels, flooring, railroad ties, tool handles, ship and vehicle construction, fuel, pulp and paper products. Bluegum is readily available in veneer and lumber. The essential oil from the tree is well known for its many medicinal uses, including cough drops and antiseptics. Eucalyptus oil, extracted from the leaves of the tree, another reason the tree is so widely planted as a plantation

Seasoning

Experts caution care in seasoning bluegum as it is “prone to checking with some tendency to warp and collapse,” according to the United States Department of the Agriculture’s Forest Service Handbook, Tropical Timbers of the World. They recommend a kiln schedule of T3-C2 for 4/4 stock “with a reconditioning treatment (steaming) at a moisture content of 20 percent to remove collapse.”

Related species

Eucalyptus grandis’ range is the east coast of Australia but has been successfully transplanted in South Africa, Brazil, Argentina, Puerto Rico, India, Uruguay, Zaire, Zambia, Zimbabwe and the United States, where it has been planted in South Florida, California, and Hawaii. The tree, known as rose gum, flooded gum and eucalyptus, is one of the most important of the commercial eucalypts. Uses for this wood pallets, veneer, poles, pulpwood and fuel. Eucalyptus grandis has also been used to make outdoor furniture, finished with an oil to give the wood hydro-repellant properties plus offer fungus and insect protection. Timber from this species is said to be as durable as teak and an average of 10 to 20 percent more dense. Wood from this species is described as honey-colored with rose highlights.

Karri, from the species Eucalyptus diversicolor, is native to southwestern Australia. It is one of the tallest of the eucalypts, capable of growing to 279 feet. Karri’s heartwood is a reddish-brown color, often with interlocked grain. It has many of the same utilitarian uses as eucalyptus bluegum, but selected pieces of karri are used for cabinetry, furniture and residential flooring and also sliced for decorative veneer and architectural paneling.

Jarrah (Eucalyptus marginata) is found on the coast of Perth in Western Australia. Slightly less tall than other eucalyptus trees, jarrah is usually 100 feet tall but can grow to 150 feet. Karri at 55 pounds per cubic foot is stronger than jarrah, which averages 51 pounds per cubic foot. Careful seasoning is important for both karri and jarrah. Jarrah is used in contruction and for marine work, including wharfs, bridge building, sea barriers, docks and harbor work. In addition to flooring, it is used for shingles, rafters, chemical vats and filter presses. Like karri, jarrah is used in furniture, paneling, and decorative veneers. It is also a great choice for turnery. Jarrah’s heartwood is a dark reddish brown, sometimes with gum veins or fleck marks caused by fungus. While karri is considered stronger than jarrah, it is not suitable for the uses where it comes in contact with water. It is also inferior to jarrah for use underground. The trees are similar in many respects, but the book Encyclopedia of Wood has a surefire method of telling the trees apart. “Jarrah and karri can be distinguished by a ‘splinter test’; a small burnt splinter of karri forms a thick white ash, while jarrah burns to a black, ashless coal.”

Eucalyptus trees, with fast-growing properties, height and strength properties plus suitability for plantation growth, are growing in popularity outside of Australia.

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