Common name: Red mahogany

Large-fruited red mahogany is a eucalyptus tree valued for its timber and originates in Australia and Papua New Guinea.

Under favourable conditions, it may attain heights of up to 30 m (100 ft) and grows fast, adding up to 2 m (6 ft) in height per year. It develops a straight, slender trunk, unbranched for more than half the tree height, supporting a densely leafy crown. However, on marginal sites, it is only around half the size. The bark on mature trees is red-brown, rough and stringy.

As with many eucalypts, the leaves change shape as the tree matures, with leaves on seedlings different from those on fully-grown trees. The mature leaves are dull green, lance-shaped, taper to a fine point and remain on the tree throughout the year.

The flowers are typical of eucalypts, being small with numerous creamy-white filaments. They bloom in the summer months in its native range and are followed by small, woody, bowl-shaped seed capsules becoming mature the following spring.

Use

Large-fruited red mahogany produces an attractive red to red-brown wood that is hard and heavy, averaging around 950 kilograms per cubic meter (59 lbs per cubic ft). It has good natural resistance to rot and decay, making it a durable hardwood suitable for indoor and outdoor construction. In particular, varieties from Papua New Guinea develop well-formed trunks for timber production.

The sawn timber is used in light and heavy construction, including boat building, joinery, cabinets, furniture and decorative veneer. Small diameter roundwood lengths are harvested for poles, posts, turnery, plywood, firewood, and charcoal.

The flowers supply only small amounts of nectar. Still, they are a significant pollen source for brood-rearing honeybees in tropical Australia.

The leaves contain Eucalyptus oil, but the reported yield is low, and the oil is of poor quality.

Climate

Grows naturally in moderately humid tropical lowland climates, generally areas with annual lows of 17 to 25°C, annual highs of 27 to 35°C, annual rainfall of 1200 to 4000 mm and a dry season of 6 months or less. 

Growing

New plants are usually started from seed that remain viable for several years, stored under cold, dry airtight conditions. Performs best on free-draining clay, loam and sand soils of a moderately acid to neutral nature, generally with a pH of 5.0 to 7.0, and on sites with full to partial sun exposure.

Problem features

Despite its widespread cultivation globally, there do not appear to be any records of escape and naturalisation anywhere. It is assessed as a low weed risk species for Hawaii by the Hawaii Pacific Weed Risk Assessment (HPWRA) project.

It has weak or brittle branches, a characteristic of Eucalyptus trees. This can result in large branches breaking off in strong winds and falling, with the potential to cause personal injury or damage to property.

Books

• Blake, S. T. & Roff, C. 1987, The honey flora of Queensland, 3rd ed., Queensland Department of Primary Industries (QLD DPI), Brisbane

• Boland D.J., Brophy J.J. & House A. P. N. 1991, Eucalyptus leaf oils, use, chemistry, distillation and marketing, Australian Centre for International Agricultural Research (ACIAR) & Commonwealth Scientific Industrial Research(CSIRO), Inkata Press, Melbourne

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

• Clarke, B. & McLeod, I. & Vercoe, T. 2009, Trees for farm Forestry : 22 Promising Species, Rural Industries Research and Development Corporation (RIRDC), Wagga Wagga, New South Wales

• Doran, J. C & Turnbull, J. W. 1997, Australian trees and shrubs : species for land rehabilitation and farm planting in the tropics, 2nd ed, Australian Centre for International Agricultural Research (ACIAR), Canberra, Australian Capital Territory

• Elevitch, C. R & Wilkinson, K. M. 2000, Agroforestry Guides for Pacific Islands, 1st ed., Permanent Agriculture Resources, Holualoa, Hawaii

• National Research Council (Board on Science and Technology for International Development) 1983, Firewood crops : shrub and tree species for energy production (Volume 2), The National Academies Press, Washington D. C.

• Webb, D. B. 1984, A Guide to species selection for tropical and sub-tropical plantations, 2nd ed., Unit of Tropical Silviculture, Commonwealth Forestry Institute, University of Oxford, Oxfordshire