Common name: Grey teak

Grey teak is a timber and shade tree originating in Australia, its native range limited to areas of subtropical forest on the east coast of the continent, extending from southern New South Wales to south-east Queensland. 

It is a fast-growing tree, to heights of up to 40 m (130 ft) in closely spaced forests, with a straight, slim trunk and a small buttress at the base. On open sites, it is more typically 10 to 20 m (33 to 66 ft) tall, with wide-spreading branches forming a densely leafy, rounded crown. The bark is grey and smooth, becoming scaly as the tree ages.

The leaves come in juvenile and adult forms. The juvenile leaves are elliptical, up to 5 cm (2 in) long, dark dull green and serrated on the margins. In comparison, the adult leaves are 15 cm (6 in) long, heart-shaped, dark glossy green and smooth on the margins. Toward the end of the dry season, they fall off the tree to conserve water, leaving the branches partially bare until the rainy season, when the new leaves grow.

The flowers are white with a purple lip, around 2 cm (0.8 in) wide and long, and come into bloom from spring to summer in its native range, held in large, loose clusters at the ends of the branches. They are followed by small, round, purple-blue fruit, about 2.5 cm (1 in) in diameter, with fleshy pulp surrounding a single seed.

Use

Grey teak produces a light- to medium-weight wood in the 500 to 600 kg per cubic meter range. It is easy to work, has little to no shrinkage and has a good natural resistance to rot, decay and wood-boring insects. This puts it in the durable softwood class, suitable for both indoor and outdoor construction. The heartwood is pale grey-brown, somewhat resembling Teak's (Tectona grandis), being plain and not highly decorative.

Well-formed logs are sawn into boards and planks for interior joinery, millwork, pattern-making, indoor and outdoor furniture, cabinets, flooring, and decking. The small-diameter roundwood is primarily used for carvings and turnery. The low-shrinkage properties of the wood enable it to be carved or turned while still green (undried), with minimal-to-no visible splitting or cracking after it has dried. 

Grey teak is occasionally cultivated as an amenity tree or ornamental in parks and gardens for its shapely form, showy flowers and fruit, and shade.

Climate

Grows naturally in moderately humid subtropical and tropical mid-elevation climates, generally areas with annual lows of 12 to 19°C, annual highs of 21 to 29°C, annual rainfall of 1000 to 2200 mm and a dry season of 4 months or less.

Growing

New plants are usually started from seed. Performs best on deep, rich, free-draining clay, loam or sand soils of a moderately acid to neutral nature, generally with a pH of 5.5 to 7.5, and on sites with partial sun exposure.

Problem features

It is an introduced species in Kenya and South Africa. Still, there does not appear to be any records of it escaping cultivation and naturalising there or in any other country.

Books

• Boland, D. & Brooker, I. & McDonald, M. W. 2006, Forest trees of Australia, 5th ed., CSIRO Publishing (Ensis), Melbourne

• Floyd, A. G. 1979, N.S.W. rainforest trees, 2nd. ed., Forestry Commission of NSW, Sydney, Australia

• Holliday, I. 2002, A field guide to Australian trees, 3rd revised editon, New Holland Publishers, Frenchs Forest, New South Wales

• Lake, M. 2015, Australian rainforest woods : characteristics, uses and identification, CSIRO Publishing, Collingwood, Victoria

• ldfield, S. & International Union for Conservation of Nature and Natural Resources & IUCN Tropical Forest Programme 1988, Rare tropical timbers, International Union for Conservation of Nature and Natural Resources, Gland, Switzerland

• Roubik, David W. (David Ward), 1951- & Food and Agriculture Organization of the United Nations 1995, Pollination of cultivated plants in the tropics, Food and Agriculture Organization of the United Nations, Rome

• Streets, R. J. & Troup, R. S. 1962, Exotic forest trees in the British Commonwealth, Oxford University Press, Oxford, England